Title of Invention

"DAMPING FORCE GENERATING MECHANISM FOR ABSORBING VIBRATION AND AXLE SUSPENSION IN A SMALL SIZED VEHICLE"

Abstract [Subject] To provide an inexpensive damping force generating mechanism capable of generating both a compression side damping force and a tensile side damping force with a simple, lightweight structure, and also provide an inexpensive axle suspension capable of simplifying the structure, reducing the weight, and effectively utilizing the space. [Solving Means] A damping force generating mechanism includes a support; a link turnably supported on the support; a lever integrated with the link; and an elastic body having one side portion locked on the lever and having the other side portion locked on the support; wherein the elastic body generates both a compression side damping force and a tensile side damping force accompanied by turning of the lever integrated with the link. An axle suspension for a small-sized vehicle, includes: a swing arm, on the rear portion of which a rear wheel is rotatably supported, the swing arm being rockably supported at the vicinity of the front end thereof by the body of the vehicle through a pivot; and an elastic member, fixed on the body, for surrounding the front end portion of the
Full Text The present invention relates to a damping force
generating mechanism for absorbing vibration and an axle suspension for a small-sized vehicle.
[Prior Art]
A damping force generating mechanism is used for various portions required for absorbing vibration, for example, used for a so-called bottom link type suspension of a motorcycle in which a front wheel is suspended from
lower end portions of a front fork through links. Here, there is shown a general example of such a bottom link type suspension in Fig. 16 (see Japanese Patent Laid-open No. Sho 62-187608) .
Referring to Fig. 16, there is shown a scooter type motorcycle 01. A steering shaft 03 is turnably fitted in a head pipe 02. A pair of right and left front forked portions 04 are integrally mounted on the lower end of the steering shaft 03. A front wheel 06 is suspended from the lower ends of the front forked portions 04 through rocking arms 05 as link members.
With respect to the rocking arm 05, the base end thereof is pivotably supported on the lower end portion of the front forked portion 04, and the free end portion thereof rotatably supports the front wheel 06. A suspension spring 07 is interposed between the upper portion of the front forked portion 04 and an approximately central portion of the rocking arm 05.
A shock load applied to the front wheel from irregularities on the ground is damped by the suspension
springs 07; however, when being applied with an abrupt shock load due to jump of the body or the like, the suspension springs are very largely rebounded after being contracted once.
In an example described in Japanese Patent Publication No. Sho 57-49432, as shown in Fig. 17, a front end of a link 012 is pivotably supported on the lower end portion of a front forked portion 011 containing a hydraulic damping mechanism; a front wheel 013 is rotatably supported on a central portion of the link 012; and a sub-cushion unit 14 is interposed between the rear end of the link 012 and the central portion of the front forked portion 011.
The sub-cushion unit 014 includes a cylindrical main body 015 pivotably mounted on the front forked portion 01l. A piston 016 is slidably inserted in the cylindrical main body 015 and is connected to a leading end of a rod
pivotably mounted on the link 012. A cushion rubber
as a damping member on the bound side of the front
wheel 013, is inserted in the cylindrical main body 015 in
such a manner as to be mounted on the upper surface of the
piston 016. A stopper rubber 019 as a stopper member on the rebound side, is inserted in the cylindrical main body 015 in such a manner as to be mounted on the lower surface of the piston 016.
The sub-cushion unit 014 thus generates a compression side damping force by the cushion rubber 018, and also generates a tensile side damping force by the stopper rubber 019, and consequently it can suppress both the bound and rebound of the front wheel 013.
The above sub-cushion unit 014 as a damping force generating mechanism, however, has a (disadvantage. Since the piston 016 is slid in the cylindrical main body 015 and the cushion rubber 018 and the stopper rubber 019 are separately provided on the upper and lower surfaces of the piston 016, the mechanism is complicated in structure, being heavy, and is expensive.
In view of the foregoing, the present invention has been made, and an object of the present invention is to provide an inexpensive damping force generating mechanism capable of generating both a compression side damping force
and a tensile side damping force with a simple, lightweight structure.
On the other hand, a motorcycle is generally configured that a rear wheel is vertically rockably supported on rear end portions of rear forked portions which are pivotably supported at front ends thereof by a body frame.
In general, a damper is interposed between the rear portion of the rear forked pottion and the body frame positioned over the rear forked portion. And, there is known an example in which an elastic member such as a spring is further provided in the vicinity of a pivotably supporting portion at the front end of the rear forked portion (see Japanese Patent Laid-open No. Sho 58-97578).
The above example is shown in Fig. 18. The front ends of rear forked portions 023 are pivotably supported by means of a supporting shaft 024 on a bracket 022 fixed on a body frame 021, so that a rear wheel 025 can be vertically
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rockably supported on the rear ends of the rear forked portions 023 extending rearward. A damper 026 is
interposed between the rear portion of the rear forked portion 023 and the body frame 021 over the rear forked portion 023.
A lower receiving portion 027 is provided in the vicinity of the pivotably supporting portion at the front end of the rear forked portion 023; an upper receiving portion 028 is provided on a portion of the body frame 021 slightly separated from the lower receiving portion 027; and a metal spring 029 is interposed between the upper and lower receiving portions 028 and 027. The use of the metal spring 029 in combination with the damper 026 makes it possible to reduce the size and weight of the damper 026.
[Problem to be Solved by the Invention]
In the above example, since both the damper 026 and the metal spring 029 are provided and also the upper and lower receiving portions 028 and 027 must be provided for the metal spring 029, the number of parts is large, the structure is complicated and heavy, and the space cannot be effectively utilized, resulting in the increased cost.
In view of the foregoing, the present invention has been made, and an object of the present invention is to provide an inexpensive axle suspension capable of simplifying the structure, reducing the weight, and effectively utilizing the space.
[Means for Solving the Problem, Function and Effect] To achieve the above object, according to an invention described in claim 1, there is provided a damping force generating mechanism including: a support; a link turnably supported on the support; a lever integrated with the link; and an elastic body having one side portion locked on the lever and having the other side portion locked on the support; wherein the elastic body generates both a compression side damping force and a tensile side damping force accompanied by turning of the lever integrated with the link.
The above mechanism has a simple structure capable of generating both a compression side damping force and a tensile side damping force by locking one side portion of the elastic body on the lever and the other side portion
thereof locked on the support. As a result, it is possible to easily reduce the weight and to reduce the cost.
According to an invention described in claim 2, in the damping force generating mechanism according to claim 1, a tensile side stopper portion is formed on a portion of the elastic body on the lever side. With this configuration, it is possible to assist generation of the tensile side damping force.
According to an invention described in claim 3, in the damping force generating mechanism according to claim 1 or 2, the elastic body has a hollow portion. With this configuration, a desirable damping characteristic can be easily obtained.
According to an invention described in claim 4, in the damping force generating mechanism according to any one of claims 1 to 3, the damping force generated by the elastic body has a progressive characteristic. With this configuration, there can be obtain/a damping characteristic in which a load is largely increased in a large displacement region as compared with a small displacement
region.
According to an invention described in claim 5, in the damping force generating mechanism according to claim 1, a restricting means for restricting the sliding motion of the electric body relative to the lever is provided at a locking portion of the lever with the elastic body. With this configuration, since the sliding motion of the elastic body relative to the lever is restricted, the damping force of the elastic body can be effectively generated.
According to an invention described in claim 6, in the damping force generating mechanism according to claim 5, the restricting means has a structure that the sliding motion of the elastic body is restricted by holding the elastic body between a flange portion formed at the leading end of the lever and a stepped portion formed on the base end of the lever. With this configuration, the sliding motion of the elastic body can be restricted with a simple structure.
According to an invention described in claim 7, in the damping force generating mechanism according to claim
5, the restricting means has a structure that the sliding motion of the elastic body is restricted by inserting a fitting pin into a fitting hole formed in both the lever and the elastic body in the direction perpendicular to the sliding surface of the locking portion. With this configuration, the sliding motion of the elastic body can be restricted with a simple structure which is also excellent in assembling performance of the elastic body.
According to an invention described in claim 8, in the damping force generating mechanism according to claim 1, the support is a forked portion and the link is a rocking arm; and a wheel is rotatably supported on the free end portions of the rocking arms pivotably supported on the lower end portions of the forked portions; the lever is integrally formed on the base end portion of the rocking arm; and the elastic body is interposed between the lower portion of the forked portion and the lever. With this configuration, the damping force generating mechanism capable of generating both a compression side damping force and a tensile side damping force with a simple structure can be provided in a wheel suspension of a vehicle.
According to an invention described in claim 9, in the damping force generating mechanism according to claim
8, the lever is formed on the rocking arm at a position
between the rocking arm and the forked portion in such a
manner as to project in the centrifugal direction from the
rocking center of the rocking arm. With this
configuration, it is possible to reduce the size and weight
of the elastic body interposed between the lower portion of
a forked portion and the lever.
According to an invention described in claim 10, in the damping force generating mechanism according to claim
9, wherein the lever is rocked in a case fixed on the lower
portion of the forked portion, and the elastic body is
provided in the case. With this configuration, the elastic
body can be easily held with a simple structure without
external exposure of the elastic body.
According to an invention described in claim 11, there is provided a damping force generating mechanism including: an elastic body which generates a damping force when being pressed; and an internal pressure generating member made repulsive against the pressing force is
inserted in the elastic body.
With this configuration, the mechanism enables a large displacement due to bending” deformation of the elastic body and thereby it enables absorption of a sufficient energy. The creep generated upon bending deformation of the elastic body can be reduced by repulsion of the internal pressure generating member inserted in the elastic body accompanied by compressed deformation of the internal pressure generating member. Accordingly, there can be obtained the damping force generating mechanism capable of reducing the characteristic change due to permanent set. The restoring ability after release of a load is also excellent due to repulsion of the internal pressure generating member.
According to an invention described in claim 12, in the damping force generating mechanism according to claim 11, the internal pressure generating member is a spring member. With this configuration, the creep of the elastic body is reduced by repulsion of the spring member
t
accompanied by the compression thereof. Accordingly, it is possible to make smaller the characteristic change due to
permanent set and to enhance the restoring ability.
According to an invention described in claim 13, in the damping force generating mechanism according to claim 11, the internal pressure generating member is a partitioned chamber containing a compressive gas or liquid. With this configuration, the creep of the elastic member is reduced by repulsion of a compressive gas or liquid compressed and deformed together with the partitioned chamber. Accordingly, it is possible to make smaller the characteristic change due to permanent set and to enhance the restoring ability.
According to an invention described in claim 14, in the damping force generating mechanism according to claim 11, the internal pressure generating member is an organic material having an elasticity. The internal pressure generating member, which is made from the organic material, can be easily molded in a shape most suitable for the application use.
According to an invention described in claim 15, in the damping force generating mechanism according to claim
14, the organic material has a hollow portion. With this configuration, when the organic material is compressed, a specific repulsive force can be obtained by the presence of the hollow portion.
According to an invention described in claim 16, in the damping force generating mechanism according to claim 14 or 15, the organic material is a polyester-urethane based material. With this configuration, it is possible to obtain a specific repulsive force by a large elasticity of a polyester-urethane based material.
According to an invention described in claim 17, there is provided a damping force generating mechanism including: an elastic body which generates a damping force when being pressed; and a restricting wall for suppressing expansion of the elastic body generated in the direction perpendicular to the pressing direction of the elastic body.
When the elastic body is pressed, the expansion of the elastic body in the direction perpendicular to the pressing direction is restricted by the restricting wall,
so that the force of the elastic body applied to the restricting wall becomes larger and the sliding resistance of the elastic body is increased. As a result, a desirable relationship of a load to a displacement can be easily obtained by the action of the sliding resistance of the elastic body in addition to the elastic characteristic of the elastic body.
According to an invention described in claim 18, in the damping force generating mechanism according to claim 17, the elastic body is separated from the restricting wall with a gap put there between at the beginning of pressing of the elastic body, and is brought in contact with the restricting wall with progress of pressing of the elastic body.
At the beginning of the pressing, since the elastic body is not brought in contact with the restricting wall with a gap put therebetween, the load is gradually increased with an increase in displacement only by the elastic characteristic of the elastic body. However, as the elastic body is pressed in a state being in contact with the restricting wall, the load is rapidly increased
with an increase in displacement by combination of the elastic characteristic and the sliding resistance of the elastic body. As a result, a desirable relationship of the load to the displacement can be obtained.
According to an invention described in claim 19, in the damping force generating mechanism according to claim 18, the contact area of the elastic body with the restricting wall is enlarged with progress of pressing of the elastic body. With this configuration, after the pressed elastic body is brought in contact with the restricting wall, the contact area of the elastic body with the restricting wall is enlarged and thereby the sliding resistance of the elastic body is increased. As a result, a desirable smooth relationship of the increased load to the increased displacement can be obtained.
According to an invention described in claim 20, in the damping force generating mechanism according to any one of claims 17 to 19, the elastic body has a hollow portion opened to the restricting wall side, and an intermediate elastic body is inserted in the hollow portion, whereby when the elastic body is pressed, the intermediate elastic
body is compressed, being swelled out of the opening of the hollow portion, and is brought in press-contact with the restricting wall.
When the elastic body is pressed, there are generated the sliding resistance due to the contact of the elastic body with the restricting wall in addition to the elastic characteristic of the elastic body, and also the sliding resistance of the intermediate elastic body due to the press-contact of the restricting wall with the intermediate elastic body compressed and swelled from the opening of the hollow portion. As a result, a desirable relationship of the load to the displacement of the elastic body can be easily obtained.
According to an invention described in claim 21, there is provided a damping force generating mechanism including: an elastic body which generates a damping force when being pressed; a hollow portion opened in the elastic body in the direction perpendicular to the pressing direction; an intermediate elastic body inserted in the
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hollow portion; and a restricting wall provided opposite to the opening of the hollow portion; wherein when the elastic
body is pressed, the intermediate elastic body is compressed, being swelled out of the opening of the hollow portion, and is brought in press-contact with the restricting wall.
At the beginning of the pressing of the elastic body, there are generated elastic characteristics of the elastic body and the intermediate elastic body. However, as the pressing of the elastic body proceeds, the intermediate elastic body is compressed, being swelled out of the hollow portion of the elastic body, and is brought in contact with the restricting wall. Thus, there is generated the sliding resistance of the intermediate elastic body. As a result, a desirable relationship of the load to the displacement of the elastic body can be easily obtained.
According to an invention described in claim 22, there is provided an axle suspension for a small-sized vehicle, including: a swing arm, on the rear portion of which a rear wheel is rotatably supported, the swing arm being rockably supported at the vicinity of the front end thereof by the body of the vehicle through a pivot; and an
elastic member, fixed on the body, for surrounding the front end portion of the swing arm positioned in front of the pivot.
The axle suspension has a simple structure in which the front end portion of the swing arm supported by the pivot is surrounded by the elastic member fixed on the body without provision of any damper, and thereby it is advantageous in reducing the number of parts, effectively utilizing the space, reducing the weight, and lowering the cost.
According to an invention described in claim 23, in the axle suspension for a small-sized vehicle according to claim 22, the elastic member is fixedly inserted in a housing integrally provided on the body. With this configuration, it is possible to facilitate the assembling work for the elastic body.
Therefore, the present invention relates to a damping
force generating mechanism for absosbing vibration in a small signed vechicle
comprising:
a support;
a link turnably supported on said support;
a lever integrated with said link; and
an elastic body having one side portion locked on said lever
and having the other side portion locked on said support;
wherein said elastic body generates both a compression side
damping force and a tensile side damping force accompanied by
turning of said lever integrated with said link.
The present invention also relates to an axle suspension for a
small-sized vehicle, comprising:
a swing arm, on the rear portion of which a rear wheel is
rotatably supported, said swing arm being rockably supported
at the vicinity of the front end thereof by the body of said
vehicle through a pivot; and
an elastic member, fixed on the body, for surrounding the
front end portion of said swing arm positioned in front of
said pivot.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[Fig. 1]
A side view of a scooter-type motorcycle including a wheel suspension to which a damping force generating mechanism according to a first embodiment is applied, with parts partially omitted.
[Fig. 2]
A side view of a front forked portion and the

vicinity thereof. [Fig. 3]
A sectional view of essential portions of the front fork portion. [Fig. 4]
A sectional view taken on line IV-IV of Fig. 3. [Fig. 5]
An exploded view in perspective of a case, lid member and locking piece. [Fig. 6]
A sectional view of an elastic rubber body. [Fig. 7]
A view seen from in the direction shown by arrow
VII of Fig. 6.
[Fig. 8]
A view seen from in the direction shown by arrow
VIII of Fig. 6.
[Fig. 9]
A view seen from in the direction shown by arrow IX of Fig. 6. [Fig. 10]
A graph showing an elastic characteristic of the elastic rubber body.
(Fig. 11]
A sectional view of essential portions of a front forked portion according to a modification. [Fig. 12]
A view seen from in the direction shown by arrow XII of Fig. 11, showing a locking portion of a lever with an elastic rubber body. [Fig. 13]
A view showing another example of the locking portion of the lever with the elastic rubber body shown in Fig. 12. [Fig. 14]
A sectional view of essential portions of a front forked portion according to another modification. [Fig. 15]
A view seen from in the direction shown by arrow XV of Fig. 14, showing a locking portion of a lever with an elastic rubber body. [Fig. 16]
A view showing a motorcycle including a prior art front wheel suspension. [Fig. 17]
A sectional view showing another prior art front
wheel suspension. [Fig. 18]
A side view of essential portions of a prior art motorcycle. [Fig. 19]
A side view of an elastic body containing a spring member according to a second embodiment. [Fig. 20]
A top view of the elastic body shown in Fig. 19. [Fig. 21]
A sectional view showing a damping force generating mechanism of a wheel suspension. [Fig. 22]
A sectional view showing the damping force generating mechanism of Fig. 21, which is in a state different from that in Fig. 21. [Fig. 23]
A graph showing an elastic characteristic of the damping force generating mechanism shown in Fig. 21. [Fig. 24]
A graph showing a change in creep amount with an elapsed time for the damping force generating mechanism shown in Fig. 21.
A sectional view of essential portions of a wheel suspension using a damping force generating mechanism according to a modification. (Fig. 33]
A transverse sectional view taken on line X-X of Fig. 32. [Fig. 34]
A sectional view of the damping force generating mechanism of Fig. 32, which is in a state different from that in Fig. 32. [Fig. 35]
A sectional view of essential portions of a wheel suspension using a damping force generating mechanism according to another modification. [Fig. 36]
A sectional view of the damping force generating mechanism of Fig. 35, which is in a state different from that in Fig. 35. [Fig. 37]
A side view of the entire configuration of a motor tricycle with a roof according to a fourth embodiment. [Fig. 38]
A perspective view showing an assembling state of a
fixed frame and a swing arm. (Fig. 39]
A side view of essential portions of a swing arm supporting structure, with parts partially omitted. [Fig. 40]
A sectional view taken on line IV-IV of Fig. 39. [Fig. 41]
A perspective view showing another example of the frame structure.
[Preferred Embodiments of the Invention]
Here after, a first embodimentent of the present inventic conficuraion scribed with reference to Figs. 1 to
10. Fig. 1 is a side view of a scooter-type motorcycle 1 including a wheel suspension to which a damping force generating mechanism in the embodiment is applied, with parts partially omitted.
A low level floor 4 is formed between a front portion 2 and a rear portion 3 of the body. A down frame 6 extends downward from a head pipe 5 provided on the front portion 2 of the body, being curved rearward from the lower end portion, and is integrated with the floor 4.
A steering shaft 7 is tunably fitted to the head pipe 5. A pair of right and left front forked portions 8 are integrally mounted on the lower end of the steering shaft 7, and they extend downward therefrom. A rocking arm 9 as a link member is rockably supported, by means of a pivot arm bolt 11, at the lower end of each front forked portion 8. A front wheel 13 is rotatably supported by the free ends of the rocking arms 9 through a front axle 12.
The front forked portion 8 is U-shaped in cross section with a front wall and both side walls. The right and left side walls at the lower end portion of the front
forked portion 8 has bolt holes. A bush 14 provided in a base end pivot portion 9a of the rocking arm 9 is fitted between both the side walls of the front forked portion 8 at a position corresponding to the bolt holes, and the bush 14 is rotatably supported by a pivot arm bolt 11 passing through the bush 14 and the bolt holes of the side walls of the front forked portion 8. Each side of the base end pivot portion 9a of the rocking arm 9 is formed in a cylindrical shape having an enlarged diameter. A plate-like lever 10 is integrated with the outer peripheral surface of the cylindrical side portion of the base end pivot portion 9a and extends therefrom in the centrifugal direction.
In a state in which the rocking arm 9 extends rearward from the base end pivot portion 9a, the lever 10 extends obliquely, upward at an angle of about 60° relative to the rocking arm 9, that is, it extends between the front forked portion 8 and the rocking arm 9.
A fan-shaped case 15 is fixedly inserted in the
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front fork portion 8 at a position adjacent to the upper portion of the base end pivot portion 9a of the rocking arm
9 rotatably supported at the lower end of the front forked portion 8.
As shown in Fig. 5, the case 15 is formed into a box-like shape having a fan-shaped side wall 15a, an outer peripheral wall 15b, and a front wall 15c and a rear wall 15d radially extending. A slot 15e is formed in the side wall 15a along the front edge, and three pieces of circular holes 15f are formed in upper and lower ends of the front wall 15c and in the upper end of the rear wall 15d in such a manner as to pass therethrough in the right and left direction, that is, in the width direction.
As shown in Fig. 5, there is provided a plate-like lid member 16 for blocking the opening, opposed to the side wall 15a, of the case 15. The lid member 16, which is formed into the same fan-shape as that of the side wall 15a, has a slot 16e corresponding to the slot 15e, and three pieces of circular holes 16f corresponding to the circular holes 15f.
A locking piece 17 is locked in the slots 15e and 16e opposed to each other. In a state in which the lid

member 16 is fitted to the case 15, only the lower side of the case 15 is opened.
An elastic rubber body 20 is contained in a case 15 covered with the lid member 16. The elastic rubber body 20 is formed into a shape shown in Figs, 6 to 9. That is, the elastic rubber body 20 has a fan-shaped cross section similar to but smaller than that of the inner space of the case 15, and also has a large projection 20a projecting from the rear surface of the fan-shaped cross section. In addition, corners at upper and lower ends of the front side of the fan-shaped cross section are slightly cut off.
A circular hole 20b and a large-sized irregular rectangular hole 20c are formed fore and aft in the elastic rubber body 20 having the above contour in such a manner as to pass through the elastic rubber body 20 in the width direction. In the elastic rubber body 20, are also formed slots 20e and 20f. The slot 20e (corresponding to the slot 15e of the above case 15} is disposed between the circular hole 2Ob and the front surface of the elastic rubber body
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20 in such a manner as to extend in parallel to the front surface. The slot 20f passes through a base portion of the
projection 20a in parallel to the rear surface of the elastic rubber body 20.
The elastic rubber body 20 exhibits a hysteresis characteristic of compression and tensile actions, and it has both elastic and damper functions.
The elastic rubber body 20, case 15, and the like are assembled as follows. The lever 10 integrated with the rocking arm 9 is made to pass through the slot 20f formed in the base portion of the projection 20a of the elastic rubber body 20, to be thus mounted in the elastic rubber body 20. The case 15 covers the elastic rubber body 20 from the left side, and the lid member 16 closes the case 15 from the right side. Thus, the lever 10 is in a state being inserted in the case 15 through the lower opening of the case 15.
The locking piece 17 is made to pass through the slot 15e of the case 15, the slot 20e of the elastic rubber body 20, and the slot I6e of the lid member 16, and hence to be fitted in the slots 15e, 20e and 16e. Then, a screw 25 is screwed in the circular hole 15f formed in the upper end portion of the rear wall 15d of the case 15 and in the
circular hole 16f of the lid member 16 corresponding to the circular hole 15f, to thus integrally fix the case 15 to the lid member 16.
The case 15 covered with the lid member 20, which is mounted to the lever 10 through the elastic rubber body 20, is inserted in the recess on the back side of the front forked portion 8 to the extent that the front wall 15c of the case 15 is brought in contact with the bottom of the recess.
Each of the right and left side walls of the front fork portion 8 has circular holes at specific upper and lower positions along the bottom. The circular holes 15f and 16f of the case 15 and the lid member 16 are aligned with the above circular holes, and bolts 26 are made to pass through these circular holes and are screwed with nuts. Accordingly, the case 15 and the lid member 16 are co-fastened to the front forked portion 8 with the bolts 26, to be thus fixed thereto.
In the assembled state, the elastic rubber body 20 is disposed in the case 15 as shown in Figs. 3 and 4. That
is, with respect to the elastic rubber body 20, the front end portion is positioned in a state being locked by the locking piece 17; the rear portion is held by the lever 10 inserted in the slot 20f; and the"projection 20a projecting rearward is allowed to be brought in contact with the rear wall 15d of the case 15.
In this way, the front wheel suspension in this embodiment has a very simple structure that the elastic rubber 20 is interposed between the front forked portion 8 and the lever 10 in a state in which the front portion thereof is locked by the locking piece 17 and the rear portion thereof is locked by the lever 10.
When the front wheel 13 is applied with a shock generated by irregularities of the ground and the rocking arm 9 is rocked, the positional states of the rocking arm 9 and the lever 10 integrated with the rocking arm 9 are changed from states indicated by a solid line of Fig. 3 to states indicated by a two-dot chain line. As a result, the lever 10 compresses the elastic rubber body 20 in the forward direction, that is, on the front forked portion 8 side, and elastically deforms it, to thereby generates a
compression side damping force.
In this case, the elastic rubber body 20 has a progressive elastic characteristic shown in Fig. 10 in which the increasing ratio of a load to a displacement is large in a large displacement region as compared with a small displacement region. Specifically, in a small displacement region that only the irregular rectangular hole 20c of the elastic rubber body 20 is deformed, a compressive stress is moderately generated to the displacement, but in a large displacement region that not only the irregular rectangular hole 20c but also the circular hole 20b are deformed, the compressive stress is rapidly increased to the displacement.
On the other hand, when the rocking arm 9 and the lever 10 are reversely rocked, the main body of the elastic rubber body 20 generates a tensile damping force, and simultaneously the projection 20a is pressed and compressed by the rear wall 15d of the case 15, thus acting as a rebound stopper.
Accordingly, while the front wheel suspension in
this embodiment has the simple structure in which the elastic rubber body 20 is interposed between the front fork portion 8 and the lever 10, it exhibits a desirable damping effect due to the function of the' elastic rubber body 20 generating both a compression side damping force and a tensile side damping force thereby effectively absorbing shock applied from the ground to the front wheel 13.
In this way, the front wheel suspension in this embodiment does not require a pivot for supporting the elastic rubber body 20 as the damping means, and has not any sliding portion for a piston or the like, so that it can obtain a stable damping characteristic without occurrence of any sliding friction and enhance the durability with a simple, lightweight, and inexpensive structure.
It is to be noted that it becomes possible to various other elastic characteristics of the elastic rubber body 20 by changing the shapes of the circular hole 20b and the irregular rectangular hole 20c of the elastic rubber body 20, and hence to easily provide an elastic body most suitable for each kind of the vehicle.
Next, the structure of a front wheel suspension disposed at the lower end portion of a front forked portion
according to a modification of the first embodiment will
be described with reference to Figs. 11 and 12. This
modification has the same basic structure as that of the
first embodiment, except for slightly changed shapes of the
parts. A base end pivot portion 4la of a rocking arm 41 is
rockably supported, by means of a pivot arm bolt 42, at the
lower end of the front forked portion 40. The rocking arm
has a plate-like lever 43 extending from the base end
pivot arm portion 4la in the centrifugal direction. A fan-
shaped case 44 adjacent to the upper side of the base end
pivot portion 4la of the rocking arm 41 is fixedly fitted
in the front forked portion 40.
An elastic rubber body 45, which has through-holes 45b and 45c passing through the elastic rubber body 45 in the width direction, is fitted in the case 44. A locking piece 46 passes through the front portion of the elastic rubber body 45 and locks it. A lever 43 is inserted in a slot 45d formed in the rear portion of the elastic rubber body 45, and a projection 45a projecting rearward from the

rear portion is allowed to be brought in contact with the rear wall of the case 44.
The lever 43 has a swelled portion 43b, a stepped portion 43c, and a flange portion 43d. As shown in Fig. 12, the swelled portion 43b is swelled right and left, that is, in the width direction on the base end side from a locking portion 43a to be locked with the elastic rubber body 45, and the stepped portion 43c is formed at the boundary between the locking portion 43a and swelled portion 43b. The flange portion 43d projects upward from the leading end of the lever 43, as shown in Fig. 11.
The lever 43 passes through the slot 45d of the elastic rubber body 45, and the elastic rubber body 45 is locked with the locking piece 43a. At the same time, the elastic rubber body 45 is held between the stepped portion 43c and the flange portion 43d of the lever 43. The sliding motion of the elastic rubber body 45 relative to the lever 43 is thus restricted by the stepped portion 43c and the flange portion 43d of the lever 43. This allows the elastic rubber body 45 to effectively generate a damping force.
Fig. 13 shows another example of the lever. A lever 50 has a fitting portion 50c on the base end side of a locking portion 50a at the boundary between the locking portion 50a and a swelled portion 50b, and also has on the leading end side a flange portion 50d projecting in the right and left direction. An elastic rubber body 51 is held between the fitting portion 50c and the flange portion 50d of the lever 50, so that the sliding motion of the elastic rubber body 45 relative to the lever 43 is restricted.
Next, another modification of the first embodiment will be described with reference to Figs. 14 and 15. The modification, which also concerns a front wheel suspension provided on the lower end portion of a front forked portion 60, is substantially similar to the above modification shown in Figs. 11 and 12 in terms of shapes of a rocking arm 61, a lever 63, a case 64, and an elastic rubber body 65, but is different therefrom in terms of the structure of restricting the sliding motion of the elastic rubber body 65 relative to the lever 63.
A circular hole 63b is formed in a plate-like locking portion 63a of the lever 63, and a circular hole 65e corresponding to the circular hole 63b is formed in the elastic rubber body 65. The circular hole 65e is continuous to a slot 65d formed in a rear projection 65a, and further to a recess formed in the opposed portion, to the slot 65d, of the rear portion of the elastic rubber body 65. A knock pin 66 is inserted in the circular hole 63b of the lever 63 and the circular hole 65e of the elastic rubber body 65.
Accordingly, the sliding motion of the elastic rubber body 65 relative to the lever 63 is restricted by the knock pin 66, so that the elastic rubber body 65 is allowed to effectively generate a damping force. The lever 63, which has not a flange portion at the leading end thereof, is easily inserted in the slot 65d of the elastic rubber body 65 upon assembly.
Although description has been made by example of the front wheel suspension for a motorcycle in the above first embodiment and modifications thereof, the present invention can be applied to a rear wheel suspension, and
used as a damper mechanism for a power transmission of an engine and a damper mechanism for a cam chain tensioner.
Hereinafter, a second embodiment of the present invention will be described with reference to Figs. 19 to 24. In the second embodiment also concerning a front suspension mechanism as in the first embodiment, parts corresponding to those in the first embodiment are indicated by the same characters. Figs, 19 and 20 shows the second embodiment, in which four holes having different shapes and passing through an elastic rubber body 120 in the width direction are formed in the elastic rubber body 120. The four holes, an elliptic hole 120b (corresponding to the slot 15e of the case 15 in the previous embodiment), an irregularly elliptic hole 120c, an developed fan-shaped hole 120d, and a contracted fan-shaped hole 120e are arranged from the front side in this order. Further, a through-slot 120f is formed in the base portion of a projection 120a along the rear surface of the elastic rubber body 120.
A metal spring member 121 as an internal pressure
generating member is inserted in the developed fan-shaped hole 120d. The spring member 121 is composed of radially extending plate springs arranged in a fan-shape corresponding to the internal space of the developed fan-shaped hole 120d. The spring member 121 is made repulsive against a compression side pressing force while generating an internal pressure.
The elastic rubber body 120 is contained in a case 15 in a state shown in Fig. 21. That is, with respect to the elastic rubber body 120, the front end portion is locked and positioned by a locking piece 17 passing through the front portion; a lever 10 is inserted in the slot 120f; and a projection 120a projecting rearward is allowed to be brought in contact with a rear wall 15d of the case 15.
As described above, the front wheel suspension in this embodiment has a simple structure in which the elastic rubber body 120 containing the spring member 121 is interposed between a front forked portion 8 and the lever 10 in the state that the front portion of the elastic rubber body 120 is locked with the locking piece 17 and the rear portion of the elastic rubber body 120 is locked with
the lever 10.
When a front wheel 13 is applied with shock generated by irregularities of the ground or a load upon braking and thereby a rocking arm 9 is rocked, the rocking arm 9 and the lever 10 integrated with the rocking arm 9 are rocked from a state shown in Fig. 21 to a state shown in Fig. 22. The lever 10 thus presses the elastic rubber body 120 forward onto the front forked portion 8, and it elastically deforms the elastic rubber body 120. As a result, the spring member 121 inserted in the elastic rubber body 120 is compressed and is made repulsive while generating an internal pressure.
In this case, the elastic rubber body 120 has an elastic characteristic shown in Fig. 23, in which the displacement of the elastic rubber body 120 is increased from the initial state having an initial strain p0 to a sufficiently large value by increasing the applied load, and then the displacement is decreased along the hysteresis curve by decreasing the load and finally it becomes zero when the load reaches zero. Accordingly, the elastic rubber body 120 can ensure a large displacement and obtain
a sufficient energy absorption, and further it improves the initial strain.
The result of an experiment of examining the generation amount of creep of the elastic rubber body 120 containing the spring member 121 is shown in Fig. 24. In Fig. 24, an example of using the prior art elastic body not containing the spring member is shown by a broken line, and the example using the elastic rubber body 120 containing the spring member 121 is shown by a solid line. As is apparent from this figure, the creep amount of the elastic rubber body 120 is significantly reduced as compared with the prior art elastic body.
The characteristic change of the elastic rubber body 120 due to fatigue is thus small. Further, the elastic rubber body 120 is excellent in restoring ability after release of load. That is, while the prior art elastic body causes approximately 100% of the permanent strain, the elastic rubber body 120 only causes approximately 40% of the permanent strain.
A modification of the second embodiment will be
described with reference to Figs. 25 and 26. The modification is the same as the second embodiment, except for an elastic body 130 and an internal pressure generating member 131 inserted in the elastic body 130. In this modification, parts corresponding to those in the second embodiment are indicated by the same characters.
The elastic body 130 is made from polyester elastomer and has an outer shape being substantially the same as that of the elastic body 120 in the second embodiment. Further, an elliptic hole 130b, and an irregularly elliptic hole 130c formed in the elastic body 130, and a slot 130f passing through the elastic body 130 along the base portion of a rear projection 130a are formed in the same shapes as those of the corresponding ones in the second embodiment. In this modification, however, the developed fan-shaped hole 120d and the contracted fan-shaped hole 120e are omitted, and instead, an irregularly circular hole 130d is formed and an internal pressure generating member 131 is inserted in the irregularly circular hole 130d.
The internal pressure generating member 131 is made
from polyester-urethane being softer and more elastic than the elastic body 130 and is formed in a cylindrical shape having a specific wall thickness. When the elastic body 130 is applied with a load and a rocking arm 9 is rocked, the rocking arm 9 and a lever 10 integrated with the rocking arm 9 are rocked from a state shown in Fig. 25 to a state shown in Fig. 26, so that the lever 10 presses the elastic body 130 forward to a front forked portion 8 and thereby it elastically deforms the elastic body 130. In such a state, the internal pressure generating member 131 inserted in the elastic body 130 is compressed and is made repulsive while generating an internal pressure.
The elastic body 130 can ensure a large
displacement and obtain a sufficient energy absorption, and it is significantly reduced in creep by the effect of the internal pressure generating member 131 and thereby it is small in characteristic change due to fatigue. Further, the elastic body 130 is excellent in restoring ability after release of a load.
In addition, the elastic body may be made from rubber in place of polyester-urethane. Also, with respect
to the internal pressure generating member 131 made from polyester-urethane, the cylindrical hollow type may be replaced with a solid type. And, a different elastic substance may be inserted in the hollow portion of the elastic body.
The internal pressure generating member may be made from an organic material having a specific elasticity, in place of polyester-urethane. In this case, the organic material can be easily molded into a shape most effective to the application use of the elastic body.
Additionally, it may be considered to form an enclosed partition chamber containing a compressive gas or liquid in the elastic body. When the elastic body is pressed and deformed, the gas or liquid contained in the partition chamber is compressed to generate an internal pressure. Such an elastic body is allowed to be significantly reduced in creep and hence to be reduced in characteristic change, and also to enhance the restoring ability after release of a load.
A third embodiment of the present invention will be described with reference to Figs. 27 to 31. In the third embodiment also concerning a front wheel suspension as in the previous embodiments, parts corresponding to those in the previous embodiments are indicated by the same characters. Fig. 28 shows the third embodiment using an elastic body 220 made from polyester elastomer. The elastic body 220 is formed in a shape being substantially similar to but smaller than that of the inner space of the case 15. The elastic body 220 has right and left side surfaces 220R and 220L which are substantially parallel to each other and are slightly curved in such a manner as to be gradually close to each other in the direction from the front side to the rear side, and it has a large projection 220a projecting from the rear portion thereof.
Three holes of different shapes are formed in the elastic rubber body 220 having such a contour. These holes, an elliptic hole 220b (corresponding to the elliptic hole 15e of the case 15 in the previous embodiment), an irregularly elliptic hole 220c, and an irregularly elliptic hole 220d are arranged from the front side in this order. Further, there is formed a slot hole 220e which passes
through the base portion of the projection 220a along the rear surface of the elastic rubber body 220.
As shown in Fig. 28, the right and left side surfaces 220R and 220L of the elastic body 220 contained in the case 15 are respectively brought in contact with a side wall 15a of the case 15 and a lid member 16 on the front side of the elastic body 220, that is, on the side locked with a locking piece 17, and they are gradually separated from the side wall 15a of the case 15 and the lid member 16 with the increased gap as nearing the rear side. In this way, the front wheel suspension in this embodiment has a simple structure in which the elastic body 220 is interposed between a front forked portion 8 and a lever 10 in such a manner that the front portion thereof is locked with the locking piece 17 and the rear portion thereof is locked with the lever 10.
When a front wheel 13 is applied with a shock generated by irregularities on the ground or a load upon braking and thereby a rocking arm 9 is rocked, the rocking arm 9 and the lever 10 integrated with the rocking arm 9 are rocked as shown in Figs. 29 and 30, so that the lever
10 presses the elastic body 220 forward to the front forked portion 8 and thereby it elastically deforms the elastic body 220.
When being pressed, the elastic body 220 is expanded in the direction perpendicular to the pressing direction, that is, in the vertical direction and also in the right and left direction. The expansion of the elastic body 220 in the right and left direction causes the right and left side surfaces 220R and 220L to be swelled and to be respectively brought in contact with the side wall 15a of the case 15 and the lid member 16. Consequently, the expansion of the elastic body 220 is suppressed by the above contact, and as the pressing of the elastic body 220 proceeds, the contact area thereof is increased, so that the sliding resistance of the elastic body 220 at the contact surface of the right and left side surfaces 220R and 220L with the side wall 15a of the case 15 and the lid member 16 is increased. Thus, as the displacement (stroke) of the elastic body 220 is increased, the sliding resistance as well as the elastic force of the elastic body
»
220 is progressively increased.
The stroke-load characteristic in this embodiment is shown by a solid line of Fig. 31. The stroke-load characteristic forms a hysteresis curve. At the beginning of the motion of the elastic body 220, that is, when the stroke is small, the sliding resistance of the elastic body 220 is small and thereby the gradient of the curve of the load to the stroke is moderate. When the stroke becomes relatively large, the sliding resistance is added to the elastic force, and thereby the gradient of the curve is increased. When the stroke becomes very large, the gradient is further increased by the action of the progressively increased sliding resistance. In this way, the front wheel suspension in this embodiment exhibits the desirable damping effect.
The action of the sliding resistance can be easily adjusted by changing the shapes of the right and left side surfaces 220R and 220L of the elastic body 220, to thereby easily obtain a specific stroke-load characteristic.
A modification of the third embodiment will be described with reference to Figs. 32 to 34. In the modification also concerning a front wheel suspension as in
the third embodiment, parts corresponding to those in the third embodiment are indicated by the same characters. An elastic body 230 is formed into the same shape as that of the elastic body 220 in the third "embodiment; however, in the elastic body 230, an intermediate elastic body 235 is inserted in an irregularly elliptic hole 230C as one of hollow portions. The intermediate elastic body 235 is made from a material smaller in elastic modulus than the elastic body 230, that is, deformable easier than the elastic body 230.
In a state before the rocking arm 9 is rocked (see Figs. 32 and 33), as shown in Fig. 33, the intermediate elastic body 235 is fitted in the irregularly elliptic hole 230c, that is, not swelled from the right and left openings of the irregularly elliptic hole 230c.
When the front wheel 13 is applied to shock generated by irregularities on the ground and the rocking arm 9 is rocked, the elastic body 230 is pressed and elastically deformed, so that the irregularly elliptic hole

230c is also compressed in the pressing direction and it compresses the intermediate elastic body 235 contained in
the hole 230c. At this time, the intermediate elastic body 235 made from a soft material is easily deformed, being expanded in the direction perpendicular to the compression direction, and is swelled from the right and left openings of the irregularly elliptic hole 230c to be brought in contact with the side wall 15a of the case 15 and the lid member 16. The expansion of the intermediate elastic body 235 is thus suppressed by the above contact, and consequently the sliding resistance thereof at the contact surface is increased.
As described above, right and left side surfaces 230R and 230L of the elastic body 230 itself are brought in contact with the side wall 15a of the case 15 and the lid member 16 respectively, so that the sliding resistance of the elastic body 230 is increased. As a result, the elastic forces of the elastic body 230 and the intermediate elastic body 235 and the sliding resistance of the elastic body 230 are further added with the sliding resistance of the intermediate elastic body 235. The stroke-load characteristic of the front wheel suspension having the above configuration is shown by a broken line of Fig. 31.

In the stroke-load characteristic of this modification, the gradient of the curve is rapidly raised in a early region with a small stroke, as compared with the characteristic of the third embodiment shown by the solid line. In this way, the front wheel suspension in this modification is allowed to change the stroke-load characteristic with a simple structure in which the intermediate elastic body 235 is inserted and hence to easily obtain a specific characteristic.
Another modification will be described with reference to Figs. 35 and 36. This modification has the same basic structure as that of the previous modification shown in Figs. 32 to 34, except that the shape of an elastic body 240 is slightly different from that of the above-described elastic body 230. In this modification, parts corresponding to those in the previous modification are indicated by the same characters.
The elastic body 240 having right and left side surfaces 24OR and 240L parallel to each other is contained in the case 15 between the side wall 15a and the lid member 16 with gaps put therebetween. As shown in Fig. 36, even
when the elastic body 240 is pressed, the right and left side surfaces 240R and 240L are not brought in contact with the side wall 15a and the lid member 16 with gaps kept therebetween. Accordingly, upon pressing of the elastic body 240, the expansion thereof is not restricted, differently from the elastic body 230 in the previous modification.
An intermediate elastic body 245 is inserted in an irregularly elliptic hole 240c of the elastic body 240, and as shown in Fig. 35, before the elastic body 240 is pressed, the intermediate elastic body 245 is contained in the irregularly elliptic hole 240c. However, as shown in Fig. 36, when the elastic body 240 is pressed, the intermediate elastic body 245 is compressed and expanded in the direction perpendicular to the compression direction, being swelled from the right and left openings of the irregularly elliptic hole 240c, and is brought in contact with the side wall 15a of the case 15 and the lid member 16. The expansion of the intermediate elastic body 245 is thus suppressed by the above contact, and thereby the sliding resistance thereof at the contact surface is increased.
Accordingly, when the elastic body 240 is pressed, the elastic force of the elastic body 240 is added with the sliding resistance of the intermediate elastic body 245, so that there can be obtained a stroke-load characteristic different from that in the previous modification.
A fourth embodiment of the present invention will be described with reference to Figs. 37 to 41. Fig. 37 is a side view showing the entire configuration of a motor tricycle 301 with a roof according to the fourth embodiment. The motor tricycle 301 is divided into a front portion 302 and a rear portion 303, which are connected to each other by a connecting portion 304. The front portion 302 has a steering system, a front wheel and a driver seat, and the rear portion 303 has a drive system, a rear wheel, and a carrier.
In the front portion 302, a handlebar 312 extending right and left is provided on the upper portion of a steering shaft 311 rotatably supported on a head pipe 310, and a front fork 313 is connected to the lower portion of
the steering shaft 311. A front wheel 314 is rotatably supported by lower ends of the front fork 313.
A down tube 315 extends rearward, obliquely downward from the head pipe 310, and the lower end of the down tube 315 is branched right and left to form a pair of main pipes 316. The main pipes 316 are curved rearward to form horizontal portions, being tilted, and are raised upright to be connected to a pair of right and left poles 319. The rear portion of a roof 320 is supported on the poles 319, and a window screen 322 extending obliquely upward from a front cover 312 covering the front portion of the head pipe 310 is connected to the front end portion of the roof 320.
A supporting shaft 304a of the connecting portion 304 rotatably supported by a bearing bracket 323 provided on the horizontal portions of the main pipes 316 projects rearward, slightly obliquely downward, and the front ends of fixed frames 331 of the rear portions 303 are connected to the rear end of the supporting shaft 304a through a bracket 329.
In the rear portion 303, as shown in Fig. 38, a pair of the fixed frames 331 extend obliquely upward, and upper portions of tilting portions 331a of the fixed frames 331 are curved in the horizontal direction to be continuous to a pair of horizontal portions 331b. The carrier 332 is provided on these horizontal portions 331b.
A bracket 330 projecting rearward is provided on the lower portion of the tilting portion 33la of each fixed frame 331. The vicinity of the front end of each of a pair of swing arms 335 is pivotably supported on the bracket 330 through a pivot 333.
A rectangular supporting housing 340 is fixed on a side surface of the tilting portion 331a at a position on the front side of the bracket 330. The front end portion of the swing arm 335 is inserted in and supported by the supporting housing 340. The pair of the right and left swing arms 335 are connected to each other by a cross-member 335b. Bearing members 336 are fixed on the rear ends of the swing arms 335, and rear wheels 337 are rotatably supported by the bearing members 336.
An internal combustion engine 338 and auxiliary equipment such as an air cleaner 339 are mounted on the swing arms 335. The supporting housing 340 is formed into an approximately rectangular parallelopiped shape in which upper and lower walls 340b and 340c and front and rear walls 340d and 340e are erected on four sides of a bottom wall 340a extending upright. The bottom wall 340a is mounted on the left side surface of the tilting portion 331a of the fixed frame 331. In such a state, the supporting housing 340 has a rectangular opening on the left side. A large cutout 340f is formed in the rear wall 340e. The rectangular opening is closed by a rectangular-plate like lid member 345.
Fig. 39 shows a state in which the lid member 345 is removed from the supporting housing 340. The supporting housing 340 contains an elastic member 350. in the supporting housing 340, projecting rods 341, each having a bolt hole, are formed at inner corners between the upper wall 340b and the front wall 340d and between the upper wall 340b and the rear wall 340e; and also projection rods,

each having a bolt hole, are formed on portions slightly apart from inner corners between the front wall 340d and
the lower wall 340c and between the rear wall 340e and the lower wall 340c. Recesses are formed between the projection rods 342 and the lower wall 340c.
The elastic member 50 includes a columnar main body 350a which has the upper end portion formed into a spherical surface and has the lower end portion extending in a square shape taken as a flange 350b. A rectangular through-hole 350c is formed in the columnar main body 350a in such a manner as to pass through the main body 350a fore and aft, and an elliptic through-hole 350d is formed in the columnar main body 350a at a position lower than the rectangular through-hole 350c in such a manner as to pass through the main body right and left.
The front end portion of the swing arm 335 formed of a square pipe is inserted in the rectangular through-hole 350c of the elastic member 350, and then the elastic member 350 surrounding the front end portion of the swing arm 335 is contained in the supporting housing 340 through the rectangular opening.
The flange 350b formed at the lower end of the
elastic member 350 is fitted in the recesses between the projection rods 342 and the lower wall 340c, and a front side arm portion 335a of the swing arm 335 is loosely fitted in the cutout 340f formed in the rear wall 340e of the supporting housing 340. A specific support portion of the front side arm portion 335a is pivotably supported on the bracket 330 by the pivot 333.
Fig. 39 shows the above state, in which the elastic member 350 is held between the upper and lower walls 340b and 340c, and the lower end flange 350b is fixedly fitted in the recesses.
The opening of the supporting housing 340 is closed with the lid member 345 in such a manner that bolt holes formed in four corner portions of the lid member 345 are matched with the bolt holes of the projecting rods 341 and 342 of the supporting housing 340. Then, the lid member 345 is fixed to the supporting housing 340 by fastening bolts 355 passing through the above bolt holes. The elastic member 350 used in this embodiment is made from a polyester elastomer having a large elastic modulus.
As described above, the swing arm 335 is supported in such a manner that the front side arm portion 335a is pivotably supported by the pivot 333, and the front end portion of the swing arm 335 is ihserted in the elastic member 350 fixedly contained in the supporting housing 340 fixed on the fixed frame 331 of the body.
In summary, the swing arm 335 is fixed on the fixed frame 331 with the front side arm portion 335a supported at two points, that is, the pivot 333 and the elastic member 350. Accordingly, the swing arm supporting structure in this embodiment has a simple structure without provision of any additional member such as a damper.
The swing arm 335 is vertically rocked around the pivot 333; however, since the elastic member 350, having the large elastic modulus, supporting the front end portion of the swing arm 335 is contained in the supporting housing 340 with the upper and lower portions thereof being held therein, the swing arm 335 is not allowed to be largely rocked in the vertical direction relative to the fixed frame 331. As a result, the swing arm 335 absorbs vibration having a small amplitude transmitted from the
rear wheel 337 as shown by a two-dot chain line of Fig. 39 and thereby it prevents such vibration from being transmitted to the fixed frame 331 and the carrier 332.
Since the swing arm 335 is collectively supported at its front side arm portion 335a by the pivot 333 and the elastic member 350 without provision of any additional damper, the swing arm supporting structure in this embodiment can effectively makes use of the space. Such a simple structure is also advantageous in reducing the number of parts, the weight, and the cost. In addition, since the elastic member 50 is contained in the supporting housing 340, the assembling work for the elastic member 350 is made simple.
The structure of supporting the swing arm 335 can elastically support the swing arm 335 applied with a load in the torsional direction, as shown by a broken line of Fig. 40. That is, the swing arm 335 is supported by the pivot 333 being not only rockable in the vertical direction but also turnable in the torsional direction. Thus, the structure in this embodiment can support the swing arm 335 applied with loads both in the vertical direction and
torsional direction.
Another example of the frame structure of the motor tricycle is shown in Fig. 41. In"this example, a fixed frame 361 has one tilting portion 361a extending obliquely upward. The upper portion of the tilting portion 361a is curved in the horizontal direction, and is branched right and left to form a pair of horizontal portions 361b extending rearward.
A bracket 360 is provided at a lower portion of the tilting portion 36la of the fixed frame 361 in such a manner as to project rearward therefrom. The vicinity of the front end of a swing arm 365 is pivotably supported on the bracket 360 by a pivot 363.
The swing arm 365 is composed of one front side arm portion 365a pivotably supported on the bracket 360, and a pair of right and left branched arm portions 365b branched right and left from the rear portion of the front side arm portion 365a and curvedly extending rearward. Rear wheels 367 are rotatably supported on the rear ends of the branched arm portions 365b through bearing members 366.
A supporting housing 370 is fixed on a side surface of the tilting portion 361a of the fixed frame 361. The front end portion of the front side arm portion 365a of the swing arm 365 is inserted in the supporting housing 370, and is supported in an elastic member contained in the supporting housing 370 as in the previous embodiment.
As described above, according to the present invention, there can be provided the frame structure in which the swing arm 365 supporting the two rear wheels 367 is supported at only one front side arm portion 365a by the fixed frame 361. Such a frame structure is advantageous in reducing the number of parts.

[Reference numerals]
1: scooter-type motorcycle, 2: body front portion, 3: body rear portion, 4: floor, 5: head pipe, 6: down frame, 7: steering shaft, 8: front forked portion, 9: rocking arm, 10: lever, 11: pivot arm bolt, 12: front axle, 13: front wheel, 14: bush, 15: case, 16: lid member, 17: locking piece, 20: elastic rubber body, 25: screw, 26: bolt, 40: front forked portion, 41: rocking arm, 42: pivot arm bolt, 43: lever, 44: case, 45: elastic body, 46: locking piece, 50: lever, 51: elastic rubber body, 60: front forked portion, 61: rocking arm, 63: lever, 64: case, 65: elastic rubber body, 66: knock pin, 220: elastic body, 221: spring member, 230:
elastic body, 231: internal pressure generating member, 320: elastic body, 330: elastic body, 335: intermediate elastic body, 340: elastic body, 345: intermediate elastic body, 301: motor tricycle, 302: vehicle front portion, 303: vehicle rear portion, 304: connecting portion, 310: head pipe, 311: steering shaft, 312: handlebar, 313: front fork, 314: front wheel, 315: down pipe, 316: main pipe, 319: pole, 320: roof, 321: front cover, 322: wind screen, 323: bearing bracket, 329: bracket, 331: fixed frame, 332: carrier, 333: pivot, 335: swing arm, 336: bearing member, 337: rear wheel, 338: internal combustion engine, 339: air cleaner, 340: supporting housing, 341, 342: projection rod, 345: lid member, 350: elastic member, 360: bracket, 361: fixed frame, 363: pivot, 365: swing arm, 366: bearing member, 367: rear wheel, 370: supporting housing





CLAIM:
1. A damping force generating mechanism for absorbing vibration in a
small-sized vehicle comprising:
a support;
a link turnably supported on said support;
a lever integrated with said link; and
an elastic body having one side portion locked on said lever and
having the other side portion locked on said support;
wherein said elastic body generates both a compression side damping
force and a tensile side damping force accompanied by turning of said
lever integrated with said link.
2. The mechanism as claimed in claim 1, wherein a tensile side stopper
portion is formed on a portion of said elastic body on said lever side.
3. The mechanism as claimed in claim 1 or 2, wherein said elastic body
has a hollow portion.
4. The mechanism as claimed in any one of claims 1 to 3, wherein in the
damping force generated by said elastic body, a load is largely
increased in a large displacement regions as compared with a small
displacement region.
5. The mechanism as claimed in claim 1, wherein a restricting means for
restricting the sliding motion of said electric body relative to said lever
is provided at a locking portion of said lever with said elastic body.
6. The mechanism as claimed in claim 5, wherein said restricting means
has a structure that the sliding motion of said elastic body is
restricted by holding said elastic body between a flange portion at the
leading end of said lever and a stepped portion formed on the base
end of said lever.
7. The mechanism as claimed in claim 5, wherein said restricting means
has a structure that the sliding motion of said elastic body is
restricted by inserting a fitting pin into a fitting hole formed in both
said lever and said elastic body in the direction perpendicular to the
sliding surface of said locking portion.
8. The mechanism as claimed in claim 1, wherein said support
comprises a forked portion and said link comprises a rocking arm;
and a wheel is rotatably supported on the free end portions of said
rocking arms pivotably supported on the lower end portions of said
forked portions; said lever is integrally formed on the base end portion
of said rocking arm; and said elastic body is interposed between the
lower portion of said forked portion and said lever.
9. The mechanism as claimed in claim 8, wherein said lever is formed on
said rocking arm at a position between said rocking arm and said
forked portion in such a mariner as to project in the centrifugal
direction from the rocking center of said rocking arm.
10. The mechanism as claimed in claim 9, wherein said lever is rocked in
a case fixed on the lower portion of said forked portion, and said
elastic body is provided in said case.
11. The mechanism as claimed in claim 1, having:
an elastic body which generates a damping force when being pressed;
and
an internal pressure generating member made repulsive against the
pressing force is inserted in said elastic body.
12. The mechanism as claimed in claim 11, wherein said internal
pressure generating member comprises a spring member.
13. The mechanism as claimed in claim 11, wherein said internal
pressure generating member has a partitioned chamber containing a
compressive gas or liquid.
14. The mechanism as claimed in claim 11, wherein said internal
pressure generating member comprises an organic material having an
elasticity.
15. The mechanism as claimed in claim 14, wherein said organic material
has a hollow portion.
16. The mechanism as claimed in claim 14 or 15, wherein said organic
material comprises a polyester-urethane based material.
17. The mechanism as claimed in claim 1, having:
an elastic body which generates a damping force when being pressed;
and
a restricting wall for suppressing expansion of said elastic body
generated in the direction perpendicular to the pressing direction of
said elastic body.
18. The mechanism as claimed in claim 17, wherein said elastic body is
separated from said restricting wall with a gap put therebetween at
the beginning of pressing of said elastic body, and is brought in
contact with said restricting wall with progress of pressing of said
elastic body.
19. The mechanism as claimed in claim 18, wherein the contact area of
said elastic body with said restricting wall is enlarged with progress
of pressing of said elastic body.
20. The mechanism as claimed in any one of claims 17 to 19, wherein
said plastic body has a hollow portion opened to said restricting wall
side, and an intermediate elastic body is inserted in said hollow
portion, whereby when said elastic body is pressed, said intermediate
elastic body is compressed, being swelled out of the opening of said hollow portion, and is brought in press-contact with said restricting wall.
21. The mechanism as claimed in claim 1, having:
an elastic body which generates a damping force when being pressed;
a hollow portion opened in said elastic body in the direction
perpendicular to the pressing direction;
an intermediate elastic body inserted in said hollow portion; and
a restricting wall provided opposite to the opening of said hollow
portion;
wherein when said elastic body is pressed, said intermediate elastic
body is compressed, being swelled out of the opening of said hollow
portion, and is brought in press-contact with said restricting wall.
22. An axle suspension using the damping force generating mechanism
as claimed in claim 1, comprising:
a swing arm, on the rear portion of which a rear wheel is rotatably supported, said swing arm being rockably supported at the vicinity of the front end thereof by the body of said vehicle through a pivot; and an elastic member, fixed on the body, for surrounding the front end portion of said swing arm positioned in front of said pivot.
23. The axle suspension as claimed in claim 22, wherein said elastic
member is fixedly inserted in a housing integrally provided on the
body.
24. A damping force generating mechanism for absorbing vibration in a
small-sized vehicle substantially as herein described with reference to
the accompanying drawings.
25. An axle suspension for a small-sized vehicle substantially as herein
described with reference to the accompanying drawings.

Documents:

2661-del-1997-abstract.pdf

2661-del-1997-claims.pdf

2661-del-1997-correspondence-others.pdf

2661-del-1997-correspondence-po.pdf

2661-del-1997-description (complete).pdf

2661-del-1997-drawings.pdf

2661-del-1997-form-1.pdf

2661-del-1997-form-13.pdf

2661-del-1997-form-19.pdf

2661-del-1997-form-2.pdf

2661-del-1997-form-3.pdf

2661-del-1997-form-4.pdf

2661-del-1997-form-6.pdf

2661-del-1997-gpa.pdf

2661-del-1997-petition-137.pdf

2661-del-1997-petition-138.pdf


Patent Number 215195
Indian Patent Application Number 2661/DEL/1997
PG Journal Number 10/2008
Publication Date 07-Mar-2008
Grant Date 21-Feb-2008
Date of Filing 19-Sep-1997
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA
Applicant Address 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 HIROKI MAKINO 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
2 TSUTOMU TOMIZAWA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
PCT International Classification Number B60G 15/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 HEI-9-064714 1997-03-18 Japan
2 HEI-8-302006 1996-11-13 Japan
3 HEI-9-064715 1997-03-18 Japan