Title of Invention

THROTTLE VALVE DEVICE

Abstract A valve main body 10 includes an enlarged drum portion 13 formed on one end of a shaft portion 12, the drum portion 13 transmitting a throttle adjustment operating force from an outside to the shaft portion. A torsion spring 27 is interposed between a cover 2 8 covering the valve main body 10 and a throttle body 8 from the side of the drum portion 13 and the drum portion 13. The torsion spring 27 is a compression coil spring type that urges the drum portion 13 in a valve closing direction. The torsion spring 27 is disposed concentrically with the valve main body 10. The torsion spring 27 includes both ends 272, 271 bent diametrically inwardly a coil portion of the torsion spring 27. The two ends 272, 271 are engaged with slits 284, 131 formed in the cover 28 and the drum portion 13, respectively. The torsion spring is thereby locked in position, being prevented from turning. (Figure 1)
Full Text THROTTLE VALVE DEVICE
BACKGROUND OF THE INVENTION
The present invention relates generally to a throttle valve device and, more particularly, to a throttle valve device, in which a torsion spring for urging a valve in a throttle closing direction is set so as to act also to press a throttle valve main body up against a throttle body along a direction of extension of a shaft portion of the throttle valve main body. The throttle body includes an electronic control unit (ECU), a throttle sensor and a dust seal.
A throttle valve device is incorporated in a carburetor or an electronic control fuel injection system in order to control an output of an internal combustion engine by adjusting an amount of air-fuel mixture drawn into a combustion chamber of the internal combustion engine. A known throttle valve device includes a throttle sensor, an idle control valve (IACV), and other elements relating to electric operations, in addition to a throttle valve main body. Japanese Patent Laid-open No. HEI 9-303164 discloses a throttle valve device, in which a housing for accommodating a throttle sensor, a pressure sensor, or the like is molded separately from a throttle body and mounted on an outer wall of the throttle body, and a case for accommodating other elements relating to electric operations is integrally molded with the throttle body.

Japanese Patent Laid-open No. HEI 4-66738 discloses a system, in which a printed wiring board constituting an ECU is disposed in a throttle body.
Conventionally, the throttle valve device includes a torsion spring provided for twisting a shaft portion of the throttle valve main body in a throttle closing direction. In addition to twisting the throttle valve main body, the torsion spring also acts to urge the shaft portion in a direction of extension of the shaft portion inside a throttle body. The torsion spring disposed concentrically with and around the shaft portion of the throttle valve main body is, however, secured in position with an end portion of the torsion spring elongated to a position offset from the shaft portion. Because of this arrangement, a force of the torsion spring to urge the shaft portion in the direction of extension of the shaft portion acts also in a direction of inclining the shaft portion. As a result, an air leak can at times occur in a clearance produced between the throttle valve main body and the throttle body.
Conventionally, screwing the ECU, the IACV, the throttle sensor, and the like to the throttle body has assembled the throttle valve device. Accordingly, there is a problem in that the number of man-hours required for assembly increases.
The conventional throttle valve device includes a dust seal disposed between a throttle shaft and a throttle body so as to prevent dust from entering a space between

these two parts. The dust seal, however, serves as resistance when a shaft portion is rotated for throttle operations. It is accordingly likely that a smooth feel in throttle operations will be impaired.
Accordingly, an object of the present invention is to provide a throttle valve device having a structure that can prevent the torsion spring from acting to incline the throttle valve main body.
Another object of the present invention is to provide a throttle valve device that can reduce the number of man-hours required for assembly.
Still another object of the present invention is to provide a throttle valve device having a dust seal structure not impairing a smooth feel in throttle operations.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
SUMMARY OF THE INVENTION
To achieve the foregoing objects, the present invention is directed to a throttle valve device for an internal combustion engine that includes: a throttle valve main body having a butterfly valve portion, a shaft portion protruding to both sides from the butterfly valve portion, and an enlarged drum portion formed on one end of the shaft portion for transmitting a throttle adjustment operating force from an outside to the shaft portion; and

a throttle body for accommodating the throttle valve main body so that the shaft portion is rotatably supported. In a first aspect of the present invention, the throttle valve device comprises a cover for covering the throttle valve main body and the throttle body from the side of the drum portion, and a torsion spring of a compression coil type interposed between the drum portion and the cover for urging the drum portion in a direction of closing the butterfly valve portion. A coil portion of the torsion spring is disposed concentrically with the throttle valve main body. The torsion spring is locked in position by both ends thereof that are bent diametrically inwardly from the coil portion and that are engaged with the cover and the drum portion, respectively.
In a second aspect of the present invention, the cover and the drum portion include slits formed diametrically in the drum portion, in which the both ends of the torsion spring are fitted.
In a third aspect of the present invention, the throttle valve main body includes an annular groove formed concentrically with the shaft portion and extending from the drum portion to a shaft portion adjacent to the drum portion. The throttle valve main body further includes a slit formed diametrically the drum portion and the shaft portion in a portion inside the annular groove. The throttle body includes a spring holding portion disposed so as to surround the drum portion in the throttle body and including grooves that are open in a throttle closing

direction and closed in a throttle opening direction. The throttle valve device further comprises a torsion spring of a compression coil type including a coil portion. One end portion is bent diametrically inwardly the coil portion while the other end portion is bent to form a plurality of overhangs overhanging diametrically outwardly the coil portion. The one end portion of the torsion spring is inserted in the slit. The coil portion is inserted in the annular groove. The overhangs on the other end portion are inserted in the grooves in the spring holding portion in a condition of exerting a twisting force on the throttle valve main body in the throttle closing direction.
In a fourth aspect of the present invention, the throttle valve device further comprises a cylindrical wall portion protruding in a longitudinal direction of the throttle valve main body from the throttle body and surrounding concentrically the drum portion and a bearing of the shaft portion, and an annular dust seal disposed between the cylindrical wall portion and the drum portion. The dust seal includes an elastic body having a peripheral edge formed into a corrugated configuration.
In a fifth aspect of the present invention, the throttle valve device further comprises a coating member formed from an elastic polymer covering an area from the butterfly valve portion to a boundary between the butterfly valve portion and the shaft portion. The coating member seals air-tightly a part between the

throttle valve main body and the throttle body. The dust seal includes an elastic polymer integrally molded with the coating member.
In a sixth aspect of the present invention, the throttle valve main body includes a plastic molding and that the dust seal and the coating member are added to the throttle valve main body through dual molding.
In the other aspects of the present invention, the throttle valve device further comprises a control unit including a housing for accommodating at least a throttle sensor connected to the throttle valve main body and a control circuit for processing an output detected by the throttle sensor. The control unit is connected to the throttle body through a protruded portion disposed on the side of either the housing or the throttle body and a hooked tab portion that is disposed on the other side of either the housing or the throttle body and to be engaged with the protruded portion.
The throttle body and the housing are formed from a resin material.
The throttle valve device further comprises a cylindrical wall portion protruding in a longitudinal direction of the throttle valve main body from the throttle body and surrounding concentrically the drum portion and a bearing of the shaft portion, a cover placed to cover an end portion of the cylindrical wall portion, a torsion spring interposed between the drum portion and the cover, the torsion spring urging the drum portion in a

direction of closing the butterfly valve portion, and a dust seal interposed between the end portion of the cylindrical wall portion and the cover.
The dust seal includes an O-ring or an annular body including an elastic polymer integrally molded relative to the cover that is a plastic molding.
A protruded portion is formed on an outer peripheral surface of the cylindrical wall portion and a hook portion to be engaged with the protruded portion is formed on the cover and that the hook portion is formed into a bend so as to be engaged with the protruded portion by being pushed axially along the cylindrical wall portion by counteracting elasticity of the dust seal and by thereafter being rotated along an outer periphery of the cylindrical wall portion.
The cylindrical wall portion is formed into a step having a narrower outside diameter on a base portion of the cylindrical wall portion and the cover includes a hook portion to be caught by the step formed in the cylindrical wall portion.
According to the first aspect of the present invention, the torsion spring is supported on the cover and the drum portion through both ends thereof bent diametrically inwardly the coil portion. Accordingly, a force that acts when the torsion spring extends acts inside the coil portion of the torsion spring. At the same time, this force acts on a center of rotation of the throttle valve main body, thereby pushing the throttle

valve main body in a longitudinal direction of the throttle valve main body. That is, a force of pressing the throttle valve main body against the throttle body is not deviated from the center. This eliminates a problem in that the throttle valve main body tilts to produce a clearance from the throttle body.
According to the second aspect of the present invention, the torsion spring bent diametrically inwardly the coil portion fits in the slit formed diametrically in the drum portion. This allows the force of the torsion spring to act correctly on the center of rotation of the throttle valve main body.
According to the third aspect of the present invention, the torsion spring is supported on the drum portion via one end portion thereof bent inwardly the coil portion. Further, the torsion spring is supported by the spring holding portion disposed so as to surround the drum portion via the plurality of overhangs overhanging from the coil on the other end of the torsion spring. The two end portions allow a repulsive force of the torsion spring to act in the direction of a central axis of rotation of the throttle valve main body.
Further, according to the third aspect of the present invention, the spring holding portion supports the torsion spring with the grooves that are open in the throttle closing direction and closed in the throttle opening direction. This allows the torsion spring to be supported by fitting the overhangs of the torsion spring

from the open side with the repulsive force of the torsion spring in the twisting direction of the torsion spring built up in advance by twisting the torsion spring.
According to the fifth aspect of the present invention, the dust seal is disposed on the end surface of the cylindrical wall portion of the throttle body and there is only a small area of contact between the dust seal and the throttle body. This prevents friction from becoming large. In addition, the corrugated peripheral edge of the dust seal helps make a friction adjustment margin large. Accordingly, the smooth operating feel during operations of throttle adjustments is not easily impaired.
According to the sixth aspect of the present invention, molding the elastic polymer integrally with the throttle valve main body helps reduce the number of parts used and the number of man-hours required for assembly.
According to the other aspects of the present invention, when the control unit is pressed against the throttle body, the tab portion is pushed and widened by the housing if the throttle body includes the tab portion. Similarly, when the control unit is pressed against the throttle body, the tab portion is pushed and widened by the throttle if the housing includes the tab portion. When the control unit is further pushed from the condition, in which the tab portion is deformed as described above, the tab portion is restored to an original state, in which the tab portion is not deformed, being caught by the

protruded portion. As such, the control unit can be connected to the throttle body through a single action procedure to pressing the control unit up against the throttle body.
The tab portion and the protruded portion are formed from a resin material (exhibiting high elasticity) that can be restored to the original shape from a relatively largely deformed state. Even with the hook of the tab portion made largely or the protruded portion protruded largely, the tab portion can climb over the protruded portion and the tab portion and the protruded portion can be restored to the original shape. Accordingly, even a more solid connection state can be achieved.
Both the throttle body and the housing are made of a resin material. This minimizes a difference in thermal deformation, thus enhancing sealing performance at mutual faying portions.
The dust seal is disposed between the cover and the throttle cover, the mutual positional relation of which does not change. Even if the throttle valve main body is rotated for throttle adjustment, therefore, there is no chance that friction will occur between the dust seal and the throttle valve main body. Accordingly, a smooth operating feel can be achieved during operations of throttle adjustments.
A good sealing performance can be derived from elasticity of the O-ring and the elastic polymer. Molding the elastic polymer integrally with the cover, in

particular, helps reduce the number of parts used and the number of man-hours required for assembly.
The cover is pushed to bring the hook portion into engagement with the protruded portion. This pushing operation temporarily compresses the dust seal, allowing the dust seal to provide a good seal as the dust seal is restored to its original shape.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention believed to be novel and the elements characteristic of the present invention are set forth with particularity in the appended claims. The Figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:
Figure 1 is a cross section view showing a throttle valve device according to a first preferred embodiment of the present invention;
Figure 2 is a cross section view showing an intake system including the throttle valve device according to the first preferred embodiment of the present invention;
Figure 3 is a front view showing the throttle valve device according to the first preferred embodiment of the present invention;
Figure 4 is a top view showing a throttle valve main

body;
Figure 5 is a cross section view showing a cover for accommodating a torsion spring;
Figure 6 is a side elevation view showing the torsion spring;
Figure 7 is an external view showing an engagement portion between an external cover and a throttle body;
Figure 8 is an exploded perspective view showing a throttle valve device according to a second preferred embodiment of the present invention;
Figure 9 is a cross section view showing the throttle valve device according to the second preferred embodiment of the present invention;
Figure 10 is a side elevation view showing the throttle valve device according to the second preferred embodiment of the present invention;
Figure 11 is a cross section view showing a throttle body;
Figure 12 is a side elevation view showing the throttle body;
Figure 13 is a plan view showing a housing of a control unit;
Figure 14 is a cross section view taken along line A-A in Figure 13;
Figure 15 is a cross section view showing a principal part of a throttle valve device according to a third preferred embodiment of the present invention;
Figure 16 is a cross section view showing a

principal part of a throttle valve device according to a fourth preferred embodiment of the present invention;
Figure 17 is a cross section view showing a principal part of a throttle valve device according to a fifth preferred embodiment of the present invention; and
Figure 18 is a perspective view showing an elastic polymer molding including a dust seal.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In describing the preferred embodiment of the present invention, reference will be made herein to Figures 1 to 18 of the drawings in which like numerals refer to like features of the invention. Features of the invention are not necessarily shown to scale in the drawings.
A specific embodiment to which the present invention is applied will be described below with reference to the accompanying drawings. Figure 2 is a cross section view showing a principal portion of an internal combustion engine including a throttle valve device according to a preferred embodiment of the present invention. Referring to Figure 2, an intake valve 3 is disposed in an intake port 2 formed in a cylinder head 1 of the internal combustion engine. An intake pipe 4 for introducing the air-fuel mixture to the intake port 2 includes a connector 5, a heat insulator 6, an air cleaner case 7, and a throttle body 8. The connector 5 is joined to the cylinder head 1. The heat insulator 6 is formed from a

heat insulating material. A fuel injection valve 9 is disposed at a portion of the intake pipe 4 formed by a lower portion of the air cleaner case 7. The fuel injection valve 9 is disposed such that an injection orifice thereof is oriented toward an inside of the intake pipe 4. The heat insulator 6 prevents heat from being directly conducted from the engine to the air cleaner case 7 and the throttle body 8. The heat insulator 6 thereby allows the air cleaner case 7 and the throttle body 8 to be formed from a resin material having relatively low heat resistance.
The throttle body 8 is built into an inside of the air cleaner case 7. An intake port 81 protrudes into the air cleaner case 7. Air cleaned by an air cleaner main body (an air filter) not shown is introduced into the intake pipe 4 through the enlarged intake port 81 disposed at an upper portion of the throttle body 8 during an intake stroke of the internal combustion engine. A throttle valve main body 10 is rotatably supported on the throttle body 8. The throttle valve main body 10 includes a butterfly valve portion (hereinafter referred to "valve portion") 11 and a shaft portion 12 supporting the valve portion 11 on the throttle body 8.
Figure 1 is a cross section view showing the throttle valve device. Figure 3 is a front view showing the throttle valve device. Figure 11 is a cross section view showing a throttle body. Figure 12 is a side elevation view showing the throttle body. Referring to

Figures 1, 2, 3, 11 and 12, the throttle valve main body 10 incorporated in the throttle body 8 includes the valve portion 11, the shaft portion 12, and a drum portion 13. The shaft portion 12 supports the valve portion 11 on the throttle body 8 by way of both ends thereof. A throttle cable (not shown) is connected to the drum portion 13. The throttle cable rotates the valve portion 11 externally for throttle opening adjustments. The valve portion 11, the shaft portion 12, and the drum portion 13 are integrally molded from resin.
The valve portion 11, and the intake pipe 4 at least at a position at which the valve portion 11 is disposed, have a generally square cross section (see Figure 3). The valve portion 11 abuts on a surface of a step formed inside the throttle body 8 in a throttle valve closed condition. This step is formed by shifting an axis of the intake pipe 4 between upstream and downstream sides with respect to the valve portion 11 (see the cross section view of the throttle body 8 shown in Figure 2).
The throttle body 8 includes a wall portion 16 and a sleeve 17. The wall portion 16 protrudes toward the side of the drum portion 13. The sleeve 17 is of a cylindrical shape formed on the side of an inner periphery of the wall portion 16. The throttle body 8 further includes a wall portion 18 and a sleeve 19. The wall portion 18 protrudes toward a side opposite to the drum portion 13. The sleeve 19 is formed on the side of an inner periphery of the wall portion 18.

The shaft portion 12 includes a shaft part 14 disposed upward of the valve portion 11 and a shaft part 15 disposed downward of the valve portion 11 in Figure 1. A bushing 20 divided into two by a plane that runs along an axis of the shaft portion 12 is disposed on an outer periphery of the shaft part 14. The shaft part 14, together with the bushing 20, is inserted into the sleeve 17 of the throttle body 8. The bushing 20 surrounding the shaft part 14 has a diameter larger than the dimension of the valve portion 11 (the length of one side of the substantially square shape) . The shaft part 15 has a diameter smaller than the dimension of the valve portion 11.
The shaft part 15 disposed downwardly in Figure 1 is inserted in the sleeve 19. An end portion of the shaft part 15 protrudes from the sleeve 19. A washer 21 is passed over the protruded portion and a stop ring 22 is fitted thereto. The washer 21 and the stop ring 22 lock the throttle valve main body 10 in position, preventing the throttle valve main body 10 from coming off the throttle body 8.
The valve portion 11 is covered with an elastic portion 23. The elastic portion 23 not only covers the valve portion 11, but also serves as a sealing member for maintaining air-tightness between the shaft portion 12 and the throttle body 8. The elastic portion 23 includes annular portions 24, 25 that extend to the shaft part 14 and the shaft part 15, respectively, from the valve

portion 11. A peripheral edge of the annular portions 24, 2 5 is corrugated such that a portion thereof in abutment with the throttle body 8 flexes easily to provide a good adhesion with the throttle body 8. It is preferable that the elastic portion 23 be formed from an elastic polymer. The elastic polymer offers superior chemical resistance. The elastic portion 2 3 is added through molding to the plastic-molded throttle valve main body 10. Specifically, the elastic portion 23 is integrated with the throttle valve main body 10 through dual molding. Dual molding proceeds as follows. Specifically, the throttle valve main body 10 is first formed through injection molding of plastic. A mold having therein secured a space, in which the elastic polymer for forming the elastic portion 23 is to be injected, is disposed around the injection-molded throttle valve main body 10. The elastic polymer is then injected into the mold. The elastic portion 23 is thereby affixed to the throttle valve main body 10.
The elastic portion 23 serves the following purposes. Specifically, the annular portions 24, 25 having corrugated peripheral edge portions seat against the steps in the throttle body 8 to provide a good seal between the shaft portion 12 and the throttle body 8 when the shaft portion 12 is urged longitudinally along the shaft portion 12 by a torsion spring 27. In addition, the elastic portion 23 covering the valve portion 11 provides a good seal between the valve portion 11 and the throttle body 8 when the valve portion 11 abuts on the steps in the

throttle body 8.
A recessed portion 26 is formed upward of the drum portion 13, that is, on a side distal from the valve portion 11. The recessed portion 26 supports one end of a coil of the torsion spring 27 acting to twist the shaft portion 12 in one direction. An external cover 28 placed on an upper portion of the wall portion 16 receives the other end of the coil of the torsion spring 27. An end portion 271 of the torsion spring 27 is locked to the shaft portion 12, while an end portion 272 is locked to the external cover 2 8. The external cover 2 8 includes a cylindrical portion 2 81 serving as a guide for preventing the torsion spring 27 from buckling. The drum portion 13 includes a groove 29 formed along an outer periphery thereof. The throttle cable (not shown) is mounted as guided by this groove 29.
Figure 4 is a top view showing the throttle valve main body 10 (as viewed from the side of the drum portion 13) . Figure 5 is a cross section view showing an external cover 28. Figure 6 is a side elevation view showing a torsion spring 27. Reference is now made to Figures 4, 5, and 6, together with Figure 1. The torsion spring 27 is a compression coil spring. Both end portions 271, 272 of the torsion spring 27 are bent inwardly of a coil diameter D of the torsion spring 27 as shown in Figure. 6. The end portions 271, 272 are preferably bent so as to be oriented toward a center of the coil diameter D. The torsion spring 27 is inserted between the drum portion 13 and the

external cover 28 covering the cylindrical wall portion 16 of the throttle body 8. A recessed portion 26 is formed upward of the drum portion 13, that is, on a side distal from the valve portion 11. The recessed portion 26 supports one end of the coil of the torsion spring 27 acting to twist the shaft portion 12 in one direction. The drum portion 13 includes a slit 131. The end portion 271 of the torsion spring 27 is fitted in this slit 131 so that the torsion spring 27 is restrained from rotating. The drum portion 13 of the throttle valve main body 10 also includes a groove 29 formed along an outer periphery thereof. The throttle cable (not shown) is mounted as guided by this groove 29.
The other end of the coil of the torsion spring 27 is received by the external cover 28 serving as a spring holder placed on an upper portion of the wall portion 16. The external cover 28 includes a cylindrical portion 281 serving as a guide for preventing the torsion spring 27 from buckling. The cylindrical portion 281 includes a slit 284. The end portion 272 of the torsion spring 27 is fitted in this slit 284 so that the torsion spring 27 is restrained from rotating.
The torsion spring 27 is set so as to urge the valve portion 11 in a throttle fully closed direction. When the throttle cable not shown is pulled, the shaft portion 12 is rotated in a direction opposite to the urging direction by the torsion spring 27, thus opening the throttle.
The external cover 28 includes an annular groove 31

disposed on a lower surface thereof. An O-ring 30 serving as a sealing member for dust seal is to be fitted into this annular groove 31. The O-ring 30 seals between the external cover 28 fitted on top of the wall portion 16 and an upper end portion of the wall portion 16.
A torsion spring 27 is inserted between an external cover 28 covering the wall portion 16 of the throttle body 8 and the drum portion 13. The torsion spring 27 allows the throttle valve main body 10 to be rotatably urged about the shaft portion 12. A recessed portion 26 is formed upward of the drum portion 13, that is, on a side distal from the valve portion 11. The recessed portion 26 supports one end of a coil of the torsion spring 27 acting to twist the shaft portion 12 in one direction. The external cover 28 placed on an upper portion of the wall portion 16 receives the other end of the coil of the torsion spring 27. The shaft portion 12 latches an end portion 271 of the torsion spring 27 and the external cover 28 latches an end portion 272. The external cover 28 includes a cylindrical portion 281 serving as a guide for preventing the torsion spring 27 from buckling. The drum portion 13 includes a groove 2 9 formed along an outer periphery thereof. The throttle cable (not shown) is mounted as guided by this groove 29.
When the torsion spring 27 urges the throttle valve main body 10 downwardly in Figure 1, the annular portions 24, 25 are seated on the throttle body 8 to provide a good seal between a fluid path inside the throttle body 8 and

an external portion.
Figure 7 is a view showing an engagement portion between the external cover and the throttle body. Referring to Figure 7, there are protruded portions 32 disposed at two places on an outer peripheral surface of the wall portion 16. The external cover 28, on the other hand, includes hook portions 33 that are engaged with corresponding ones of the protruded portions 32. Each of the hook portions 33 is a bend including a drooping portion 331 and a horizontal portion 332. The horizontal portion 332 extends horizontally from the drooping portion 331 to run beneath the protruded portion 32.
The external cover 28 is secured to the wall portion 16 as detailed in the following. Specifically, the external cover 28 is placed from an upward direction to the wall portion 16 with the hook portions 33 located at positions, at which the hook portions 33 do not interfere with the protruded portions 32. The O-ring 30 is disposed in the annular groove 31 in advance. When the external cover 28 is placed over the wall portion 16, the external cover 28 is rotated in an extended direction R of the horizontal portion 332 so that the horizontal portion 332 is engaged with a lower surface of the protruded portion 32. Turning operation of the external cover 28 relative to the wall portion 16 is performed with the external cover 28 pressed up against an end surface of the wall portion 16 so as to compress the O-ring 30. The hook portions 33 are thus hooked onto the protruded portions 32

through the foregoing operation. An elastic force for restoring the O-ring 30 to an original shape thereof acts when a pressing force against the external cover 28 is then released. As a result, the hook portions 33 and the protruded portions 32 are engaged with each other with a sealing condition between the external cover 28 and the wall portion 16 secured.
The wall portion 18 is mounted with a control unit 34 formed from a plastic material. The control unit 34 includes a throttle sensor 35, a coupling shaft 3 6, a control board 37, and a block or a housing having a built-in IACV mechanism not shown. Figure 13 is a plan view showing a housing of a control unit. Figure 14 is a cross section view taken along line A-A in Figure 13. The control board 37 includes a circuit (that may be configured using a microprocessor) having at least a function of controlling the IACV mechanism by processing an output detected by the throttle sensor 35. The housing of the control unit 34 includes a first portion 341 and a second portion 342. The first portion 341 supports the coupling shaft 36 connecting the shaft portion 12 of the throttle valve main body 10 and the throttle sensor 35. The first portion 341 includes duct lines 40, 41 connecting idle ports 38, 39 disposed in the wall portion 18 with the IACV mechanism, or an auto throttle valve mechanism. The second portion 342 is joined to the first portion 341 using a plurality of setscrews 42. The throttle sensor 35, the control board 37, and the IACV

mechanism not shown are accommodated in the second portion 342.
A cap 43 is fitted over the second portion 342. The cap 43 is fitted onto an annular portion 343 protruding from the second portion 342. A tab 344 formed in part of the annular portion 343 is then engaged with a hole 431 on the side of the cap 43, thus securing the cap 43 in position.
The wall portion 18 includes a flange 181 on an end portion thereof. The first portion 341 includes a plurality of tabs 345 that are hooked onto the flange 181. The tabs 345 are shaped to follow a profile of an end surface of the flange 181. A jaw 182 of the flange 181 catches the tabs 345 and the control unit 34 is thereby connected to the throttle body 8. The housing of the control unit 34 and the throttle body 8 are made of a plastic material. When the control unit 34 is pressed against the flange 181, therefore, the tabs 345 are pushed and widened. When the control unit 34 is further pressed, the jaw 182 of the flange 181 catches leading end hook portions of the tabs 345. Elasticity of the tabs 345 maintains the engagement condition.
The throttle valve main body 10 is assembled to the throttle body 8 as detailed in the following. Specifically, the throttle valve main body 10 is inserted into the throttle body 8 from the side of the shaft part 15 relative to the sleeve 17. Let the shaft part 15 passes through the sleeve 19 and allow an end portion of

the shaft part 15 to protrude from the sleeve 19. Then, fit the washer 21 and the stop ring 22 to an outer periphery of the end portion of the shaft part 15. The throttle valve main body 10 has the following arrangements so as to allow the throttle valve main body 10 to be assembled relative to the throttle body 8 from one direction. Specifically, the bushing 20 has a diameter larger than the dimension of the valve portion 11 and the shaft part 15 has a diameter smaller than the dimension of the valve portion 11. Nonetheless, the shape of the shaft portion 12 is not limited to this shape. Specifically, the diameter of the shaft part 14 may be enlarged like the bushing 20, thereby eliminating the need for the separate type bushing 20. This arrangement also allows the throttle valve main body 10 to be assembled to the throttle body 8 from one direction.
The throttle valve main body 10 is given a positive sealing performance when a repulsive force of the torsion spring 27 presses the peripheral edge portion of the elastic portion 23 up against the throttle body 8. Furthermore, if the stop ring 22 is fitted to the shaft portion 12 with a thrust load being applied in a direction oriented from the side of the shaft part 14 toward the side of the shaft part 15, even a greater sealing performance can be achieved.
Figure 8 is an exploded perspective view showing a throttle valve device according to a second preferred embodiment of the present invention. Figure 9 is a cross

section view showing the throttle valve device according to the second preferred embodiment of the present invention. Figure 10 is a side elevation view showing the throttle valve device according to the second preferred embodiment of the present invention. Referring to Figures 8 through 10, the throttle valve device includes a throttle body 8, a throttle valve main body 10, and a torsion spring 27. The throttle valve main body 10 is inserted in the throttle body 8. The torsion spring 27 urges the throttle valve main body 10 in the direction of an arrow Rl, that is, in the direction of closing the throttle valve. In addition, the torsion spring 27 urges the throttle valve main body 10 in the direction of an arrow T, that is, in the direction of pushing the throttle valve main body 10 into the throttle body 8. The torsion spring 27 includes a coil portion 27 5 and an overhang portion 276 formed by subjecting one end of the coil portion 275 to a bending operation. A locking portion 277 is formed on the other end of the coil portion 275. Bending the other end of the coil portion 27 5 inwardly toward a center of a coil diameter forms the locking portion 277.
When disassembled, the torsion spring 27 is in a freely extended state as shown by reference numeral 27a in Figure 9. When completely assembled, the torsion spring 27 is in a compressed state as shown by reference numeral 27 in Figure 9. Specifically, the coil portion 275 of the torsion spring 27 is pushed and accommodated in the

throttle valve main body 10 when completely assembled. The overhang portion 276 of the torsion spring 27 is protruded from the throttle valve main body 10. Both ends 276a, 276b of the overhang portion 276 are engaged with grooves 84, 85 in stays 82, 83 that serve as spring holding portions provided in the throttle body 8.
The throttle valve main body 10 also includes an annular groove 121 that extends from a drum portion 13 to a shaft part 14. The coil portion 275 of the torsion spring 27 is housed in this annular groove 121. The bent locking portion 277 of the coil portion 275 fits into a slit formed so as to be slotted diametrically the drum portion 13 and the shaft part 14 of the throttle valve main body 10.
Referring to Figure 10, a throttle cable 50 is mounted on the drum portion 13. One end of the throttle cable 50 is secured to the drum portion 13 with a pin 51 fitted in a pin aperture 133 in the drum portion 13. The throttle cable 50 is wound around an outer periphery of the drum portion 13 along a groove 29 and extended into a guide tube 52.
The torsion spring 27 is assembled to the throttle valve main body 10 as detailed in the following. Specifically, the locking portion 277 on the end of the coil portion 275 is first fitted in the slit 122. The coil portion 275 is then compressed. When the torsion spring 27 is compressed until the overhang portion 276 is close to the same level as the grooves 84, 85, the torsion

spring 27 is twisted in the direction of the arrow Rl until the ends 276a, 27 6b of the overhang portion 27 6 move part the grooves 84, 85 in the stays 82, 83. Then, at that position, the overhang portion 27 6 is backed off in the direction opposite to the arrow Rl to be fitted in the grooves 84, 85.
According to the second preferred embodiment of the present invention, the spring holding portions (stays) 82, 83 to be engaged with the ends 276a, 276b of the overhang portion 276 of the torsion spring 27 are integrally formed with the throttle body, there is no need to provide a spring receiver as a separate member. In addition, one end of the torsion spring 27 is supported on the throttle body 8 evenly through both ends of the overhang portion 276, while the other end of the torsion spring 27 is supported at the center of a shaft portion 12 of the throttle valve main body 10. This means that there is no eccentric load applied in an extension direction of the shaft portion 12 of the throttle valve main body 10.
Figure 15 is a cross section view showing a principal part of a throttle valve device according to a third preferred embodiment of the present invention. The same reference numerals as those used in Figures 1 through 3 and 7 indicate like or identical parts. In the throttle valve device described with reference to Figures 1 and 3, the first portion 341 of the control unit 34 is provided with the tabs 345 that are caught by the flange 181 of the wall portion 18 included in the throttle body 8. In the

throttle valve device according to the second preferred embodiment of the present invention shown in Figure 15, on the other hand, a tab 183 is formed on a flange 181 of a wall portion 18 of a throttle body 8. The tab 183 is engaged with a flange 346 of a control unit 34. In the throttle valve device according to the second preferred embodiment of the present invention, too, a housing of the control unit 34 and the throttle body 8 are formed of a plastic material. When the control unit 34 is pressed against the wall portion 18, the tab 183 is pushed and widened. When the control unit 34 is further pushed, a jaw 347 of the flange 34 6 catches a leading end hook portion of the tab 183. Elasticity of the tab 183 maintains the engagement condition.
Figure 16 is a cross section view showing a principal part of a throttle valve device according to a fourth preferred embodiment of the present invention. The same reference numerals as those used in Figures 1 and 3 indicate like or identical parts. In the throttle valve device described with reference to Figures 1 and 3, the external cover 28 is secured in position by being rotated such that the protruded portions 32 of the throttle body 8 catch the L-shaped hook portions 33. In the throttle valve device shown in Figure 16, on the other hand, an external cover 28 is made to be deeper so as to form a cylindrical portion 282 that extends up to a lower portion of a wall portion 16. In addition, an end portion 283 of the cylindrical portion 282 is formed into a hook shape so

as to be hooked onto a lower surface 161 of the wall portion 16. Further, an annular dust seal 44 having a rectangular cross section is disposed at a portion of the external cover 28, on which an end surface of the wall portion 16 of the throttle body 8 abuts.
When this external cover 28 is pressed from the side of the end portion of the wall portion 16 (from the upper side in Figure 16), the end portion 283 is expanded. The external cover 28 is then further pressed downwardly along the wall portion 16. When the external cover 28 is pressed to the extent that the end portion 2 83 reaches the lower surface 161 of the wall portion 16, the hook on the end portion 283 is hooked onto the lower surface 161 of the wall portion 16. This results in the external cover 28 being secured to the throttle body 8.
Like an elastic portion 23, the annular dust seal 44 can be formed from an elastic polymer. The annular dust seal 44 may be formed separately from the external cover 28, or integrally with the external cover 28 through dual molding. More specifically, the external cover 2 8 is first molded from a plastic. The external cover 28 is then surrounded by a mold having a dimension including the annular dust seal 44. The elastic polymer is finally injected into a space between the mold and the external cover 28.
In the throttle valve device configured as shown in Figure 1, the annular dust seal 44 shown in Figure 16 may be used instead of the O-ring 30.

A throttle valve device according to a fifth preferred embodiment of the present invention will be described. Figure 17 is a cross section view showing a principal part of a throttle valve device according to a fifth preferred embodiment of the present invention. The same reference numerals as those used in Figures 1 and 16 indicate like or identical parts. Referring to Figure 17, a shaft part 14 of a throttle valve main body 10 has a dimension larger than a valve portion 11. This larger shaft part 14 is inserted in, and supported by, a wall portion 16 of a throttle body 8 via a bushing 45 having a wall thickness smaller than the aforementioned bushing 20. One end of a torsion spring 27 is fixed to, and supported on, the shaft part 14. The other end of the torsion spring 27 is secured to the throttle body 8.
A dust seal 46 is disposed in a boundary portion (a step portion) between a drum portion 13 and the shaft part 14. The dust seal 46 has a corrugated peripheral edge 47. One side surface (an upper surface in Figure 17) of the peripheral edge 47 abuts on a lower surface of the drum portion 13. The other side surface (a lower surface in Figure 17) of the peripheral edge 47 abuts on an upper surface of the wall portion 16. The dust seal 46 thereby prevents entry of dust into a space between the shaft part 14 and the wall portion 16. Because of the corrugated peripheral edge 47 of the dust seal 46, the dust seal 46 can reduce friction between the wall portion 16 and the drum portion 13, while preventing entry of dust.

The dust seal 46 can be formed integrally with, and as part of, the aforementioned elastic portion 23 as a coating member. Specifically, an elastic polymer can be added together with the elastic portion 23 to the throttle valve main body 10 through injection molding.
Figure 18 is a perspective view showing the elastic portion 23 including the dust seal 46 integrally molded in the throttle valve main body 10. An annular portion 24 of the elastic portion 23 is connected to the dust seal 46 by a coupling portion 48. A relief (a recessed portion) is formed in the shaft part 14 at a portion corresponding to the coupling portion 48.
The entire disclosures of Japanese Patent Application Nos. 2004-277762, 2004-277761 and 2004-277763 filed on September 24, 2004 including the specifications, claims, drawings and summaries are incorporated herein by reference in its entirety.
While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications, and variations as falling within the true scope and spirit of the present invention.
Thus, having described the invention, what is claimed is:






/I.) In a throttle valve device for an internal
combustion engine that includes: a throttle valve main body having a butterfly valve portion, a shaft portion protruding to both sides from the butterfly valve portion, and an enlarged drum portion formed on one end of the shaft portion for transmitting a throttle adjustment operating force from an outside to the shaft portion; and a throttle body for accommodating the throttle valve main body so that the shaft portion is rotatably supported;
the throttle valve device for an internal combustion engine being characterized in that: /
the throttle valve device comprises a cover for covering the throttle valve main body and the throttle body from the side of the drum portion, and a torsion spring of a compression coil type interposed between the drum portion and the cover for urging the drum portion in a direction of closing the butterfly valve portion; and
a coil portion of the torsion spring is disposed concentrically with the throttle valve main body, and the torsion spring is locked in position by both ends thereof that are bent diametrically inwardly from the coil portion and that are engaged with the cover and the drum portion, respectively.
(2A The throttle valve device according to claim 1, wherein the cover and the drum portion comprise slits

formed diametrically in the drum portion, in which the both ends of the torsion spring are fitted.
^3^ In a throttle valve device for an internal combustion engine that includes: a throttle valve main . body having a butterfly valve portion, a shaft portion protruding to both sides from the butterfly valve portion, and an enlarged drum portion formed on one end of the shaft portion for transmitting a throttle adjustment operating force from an outside to the shaft portion; and a throttle body for accommodating the throttle valve main body so that the shaft portion is rotatably supported;
the throttle valve device for an internal combustion engine being characterized in that: /
the throttle valve device comprises an annular groove formed concentrically with the shaft portion and extending from the drum portion to a shaft portion adjacent to the drum portion, a slit formed diametrically in the drum portion and the shaft portion inside the annular groove, a spring holding portion disposed so as to surround the drum portion in the throttle body and including grooves that are open in a throttle closing direction and closed in a throttle opening direction, and a torsion spring of a compression coil type including a coil portion, one end portion being bent diametrically inwardly from the coil portion while the other end portion being bent to form an overhang portion extending diametrically outwardly from the coil portion; and

the one end portion of the torsion spring is inserted in the slit, the coil portion is inserted in the annular groove, and the overhang portion on the other end portion is inserted in the grooves in the spring holding portion with a twisting force being applied to the throttle valve main body in the throttle closing direction.
(4/ In a throttle valve device for an internal combustion engine that includes: a throttle valve main body having a butterfly valve portion, a shaft portion protruding to both sides from the butterfly valve portion, and an enlarged drum portion formed on one end of the shaft portion for transmitting a throttle adjustment operating force from an outside to the shaft portion; and a throttle body for accommodating the throttle valve main body so that the shaft portion is rotatably supported;
the throttle valve device for an internal combustion engine being characterized in that:
the throttle valve device comprises a cylindrical wall portion protruding in a longitudinal direction of the throttle valve main body from the throttle body and surrounding concentrically the drum portion and a bearing of the shaft portion, and an annular dust seal disposed between the cylindrical wall portion and the drum portion; and
the dust seal includes^an gX^sjtic^body having a peripheral edge formed into a corrugated conFigureuratipn.

/T} The throttle valve device according to claim 4, further comprising a coating member formed from an elastic polymer^^covgrijig an area from the butterfly valve portion to a boundary between the butterfly valve portion and the shaft portion, the coating member sealing air-tightly a part between the throttle valve main body and the throttle body, wherein the dust seal includes an elastic polymer , jtHrbegrally-molded wi~th—the coating member. /
6. The throttle valve device according to claim 4, wherein the throttle valve main body includes a plastic molding, and the dust seal and the coating member are added to the throttle valve main body through dual molding.

Documents:

1319-CHE-2005 AMENDED PAGES OF SPECIFICATION 27-04-2011.pdf

1319-CHE-2005 AMENDED CLAIMS 27-04-2011.pdf

1319-che-2005 form-3 27-04-2011.pdf

1319-CHE-2005 OTHER PATENT DOCUMENT 27-04-2011.pdf

1319-CHE-2005 POWER OF ATTORNEY 27-04-2011.pdf

1319-CHE-2005 EXAMINATION REPORT REPLY RECIEVED 27-04-2011.pdf

1319-CHE-2005 CORRESPONDENCE OTHERS.pdf

1319-CHE-2005 CORRESPONDENCE PO.pdf

1319-CHE-2005 FORM 18.pdf

1319-che-2005-abstract.pdf

1319-che-2005-claims.pdf

1319-che-2005-correspondnece-others.pdf

1319-che-2005-description(complete).pdf

1319-che-2005-drawings.pdf

1319-che-2005-form 1.pdf

1319-che-2005-form 3.pdf

1319-che-2005-form 5.pdf

1319-che-2005-other-documents.pdf


Patent Number 248665
Indian Patent Application Number 1319/CHE/2005
PG Journal Number 31/2011
Publication Date 05-Aug-2011
Grant Date 02-Aug-2011
Date of Filing 19-Sep-2005
Name of Patentee HONDA MOTOR CO., LTD.
Applicant Address 1-1 MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO,
Inventors:
# Inventor's Name Inventor's Address
1 YAMAMOTO, TOSHIO C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1 CHUO 1-CHOME WAKO-SHI, SAITAMA
2 IIMURO, AKIHIRO C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1 CHUO 1-CHOME WAKO-SHI, SAITAMA JAPAN
3 HIKICHI, TOICHIRO C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1 CHUO 1-CHOME WAKO-SHI, SAITAMA JAPAN
4 SHIMIZU, MASAHIRO C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1 CHUO 1-CHOME WAKO-SHI, SAITAMA JAPAN
PCT International Classification Number F02D 9/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2004-277762 2004-09-24 Japan
2 2004-277763 2004-09-24 Japan
3 2004-277761 2004-09-24 Japan