Title of Invention

A FUEL COCK-MOUNTING STRUCTURE IN A MOTORCYCLE

Abstract "A FUEL COCK-MOUNTING STRUCTURE IN A MOTORCYCLE" A fuel cock-mounting structure in a motorcycle, the motorcycle comprising an engine suspended on a vehicle body frame assembly comprising a main frame extending in a rearward declined manner from a head pipe, the engine being disposed below said main frame; an air cleaner and a carburetor disposed above said engine; and a fuel cock of a negative pressure operated type operated by an intake negative pressure in the engine, the fuel cock being incorporated in an intermediate portion of a fuel supply line which connects a fuel tank disposed below a riding seat supported at a rear portion of the vehicle body frame assembly and said carburetor to each other, the fuel cock-mounting structure being characterized in mat said fuel cock incorporated in an intermediate portion of said fuel supply line extending in a forward declined manner from said fuel tank and connected to said carburetor is mounted to an intake pipe which connects said carburetor and the engine to each other.
Full Text The present invention relates to a motorcycle in which an engine is suspended on a vehicle body frame assembly including a main frame extending in a rearward declined manner from a head pipe and is disposed below the main frame; an air cleaner and a carburetor are disposed above the engine; and a fuel cock of a negative pressure operated type operated by an exhaust negative pressure in the engine is incorporated in an intermediate portion ?f a fuel supply line which connects a fuel tank disposed below i riding seat supported at a rear portion of the vehicle body frame assembly and the carburetor to each other, and particularly, the present invention relates an improvement in a fuel cock-mounting structure. (ACKGROUND ART
Such a motorcycle is conventionally known, for example, from Japanese Patent Publication No.7-106711. In this lotorcycle, a fuel cock of a negative pressure operated type, hich is mounted between a fuel tank disposed below a riding eat and a carburetor disposed in front of and below the fuel ank, is disposed below the fuel tank and mounted to the fuel ank.
In the conventional known motorcycle, however, the fuel ock is disposed at a location spaced apart from the carburetor

and hence, a negative pressure take-off line for taking off a negative pressure from an intake device including the carburetor and conducting it to the fuel cock is prolonged, and moreover, the length of a line section of the fuel supply line, which connects the carburetor and the fuel cock to each other, is also increased. Therefore, when air enters the fuel supply line with the stoppage of the supplying of fuel from the fuel tank, a lot of time is taken to exchange the air and the fuel in the fuel supply line during subsequent supplying of the fuel, and a relief valve or the like for withdrawal of the air is required.
The present invention has been accomplished with such sircumstanceslnview, and it is an object of the present invention to provide a fuel cock-mounting structure in a motorcycle, therein the negative pressure take-off line between the intake levice and the fuel cock can be shortened and moreover, an sxclusive part for withdrawing the air from the fuel supply line .s not required to enable a reduction in number of parts. 1ISCL0SURE OF THE INVENTION
To achieve the above object, according to a first aspect tnd feature of the present invention, there is provided a fuel :ock-mountlng structure In a motorcycle, the motorcycle lomprising an engine suspended on a vehicle body frame assembly ncluding a main frame extending in a rearward declined manner rom a head pipe, the engine being disposed below the main frame; n air cleaner and a carburetor disposed above the engine; and fuel cock of a negative pressure operated type operated by

an intake negative pressure in the engine, the fuel cock being incorporated in an intermediate portion of a fuel supply line which connects a fuel tank disposed below a riding seat supported at a rear portion of the vehicle body frame assembly and the carburetor to each other, the fuel cock-mounting structure feeing characterized in that the fuel cock incorporated in an Intermediate portion of the fuel supply line extending in a forward declined manner from the fuel tank and connected to the carburetor is mounted to an intake pipe which connects the carburetor and the engine to each other.
With such arrangement of the first feature, the fuel cock can be mounted in proximity to the carburetor and hence, the negative pressure take-off line for conducting the negative pressure from the Intake device to the fuel cock can be shortened, and a line section of the fuel supply line which connects the carburetor and the fuel cock to each other can be shortened. Moreover, the fuel supply line connecting the fuel tank and the carburetor to each other is arranged in the forward inclined manner. Therefore, even if air enters the line section with the stoppage of the supplying of fuel from the fuel tank, the fuel can be filled quickly in the entire fuel supply line during subsequent supplying of the fuel, even if an air-withdrawing operation is omitted. Thus, it is possible to quickly supply the fuel to the carburetor, while eliminating the need for a part such as a relief valve for withdrawing the air to enable a reduction in number of parts.

According to a second aspect and feature of the present invention, in addition to the arrangement of the first feature, the fuel cock is mounted to a mounting stay integrally provided on the intake pipe. With such arrangement, the fuel cock is mounted to the intake pipe of the intake device and hence, the degree of freedom for disposition of the fuel cock can be increased, as compared with a case where a fuel cock is mounted to a fuel tank.
According to a third aspect and feature of the present invention, in addition to the arrangement of the first feature, the fuel cock is disposed on a side opposite from the carburetor with respect to the main frame. With such arrangement, it is possible to easily arrange the fuel supply line and the negative pressure take-off line. BRIEF DESCRIPTION OF THE DRAWINGS
Figs.l to 6 show an embodiment of the present invention. Fig.l is a side view of a motorcycle; Fig.2 is a left side view of a section of the motorcycle in the vicinity of an engine; Fig.3 is a right side view of a section of the motorcycle in the vicinity of the engine; Fig. 4 is a view taken in the direction of an arrow 4 in Fig.2 with a main frame omitted; Fig.5 is an enlarged sectional view taken along a line 5-5 in Fig.3; and Fig.6 Is an enlarged sectional view taken along a line 6-6 in Fig.2. BEST MODE FOR CARRYING OUT THE INVENTION
Referring first to Fig.l, a vehicle body frame assembly

P of a motorcycle includes a head pipe 12 for carrying a front fork 11 steerably, a main frame 13 extending rearwards and downwards from the head pipe 12, and a pair of left and right rear frames 14 connected to a rear portion of the main frame 13 and extending rearwards and upwards. A front wheel WF is rotatably carried at a lower end of the front fork 11, and a steering handlebar 15 is connected to an upper end of the front fork 11.
Referring also to Figs. 2 and 3, hanger plates 16 are secured to opposite sides of an intermediate portion of the main frame 13, respectively, and pivot plates 17 are secured to opposite sides of a rear portion of the main frame 13.
An engine E having a cylinder axis CI inclined forwards is disposed below the main frame 13 and suspended on the vehicle body frame assembly F, so that it is supported on the hanger plates 16 and the pivot plates 17. Foot steps 18, on which an occupant puts his feet, are mounted on opposite sides of the engine E.
A cylindrical support shaft 20 is provided on the pivot plate 17. A pair of left and right rear forks 21 are vertically oscillatably carried at their front ends on opposite ends of the support shaft 20, and a rear wheel WR is pivotally carried between rear ends of the rear forks 21.
An upper portion of the rear wheel WR is covered with a rear fender 24 mounted on the rear frames 14, and a fuel tank 25 is disposed above the rear fender 24 and supported on the

rearrrames 14. A tandem seat 26 which is a riding seat is disposed to cover the fuel tank 25, and rear cushion units 27 are mounted between the rear frames 14 and the rear forks 21, respectively. The vehicle body frame assembly F is covered with a vehicle body cover 30 made of a synthetic resin. The vehicle body cover
30 includes a pair of left and right main frame side cover elements
31 for covering opposite sides of the main frame 13, a pair of
left and right leg shields 32 fastened to front portions of the
main frame side cover elements 31 so as to cover an occupant's
legs from the front, a front top cover element 33 leading to
the leg shields 32 to cover the head pipe 12 from the front,
an upper cover element 34 leading to the front top cover element
33 to cover the head pipe 12 from the rear and to cover the main
frame 13 from above, an under cover element 35 leading to lower
portions of the main frame side cover elements 31, and a pair
of left and right rear side cover elements 36 for covering a
rear portion of the vehicle body frame assembly F along with
most of the fuel tank 25 from opposite sides.
Referring also to Fig.4, an intake device 40 including an air cleaner 37, a carburetor 38 and an Intake pipe 39 is disposed above the engine E.
A pair of mounting plate sections 37a, 37a are integrally provided at an upper portion of the air cleaner 37 to sandwich the main frame 13 from opposite sides and are fastened to opposite sides of the main frame 13 by bolts 41, 41. Namely, the air cleaner 37 is fixed to the main frame 13.

The carburetor 38 disposed above a cylinder head 42 of the engine E is connected at its upstream end directly to the air cleaner 37, and the intake pipe 39 connected at its upstream end to a downstream end of the carburetor 38 is formed curved Into a substantially C-shape and connected at its downstream end to a sldewall of an upper portion of the cylinder head 42, so that it is connected to an intake port 43 disposed in the upper portion of the cylinder head 42.
An exhaust pipe 45 is connected at its upstream end to a sidewall of a lower portion of the cylinder head 42, so that it is connected to an exhaust port 44 disposed in the lower portion of the cylinder head 42. The exhaust pipe 45 is extended rearwards from the cylinder head 42 and connected to an exhaust muffler 46 (see Fig.l) disposed on the right of the rear wheel WR.
Exhaust secondary air is supplied to the exhaust port 44 in the cylinder head 42 of the engine E, and a secondary air control valve 48 for controlling the supplying of the secondary air to the exhaust port 44 is disposed between a cell motor 50 mounted to an upper portion of a crankcase 49 in the engine E and the carburetor 38 and between the engine E and the main frame 13.
Referring to Fig.5, the secondary air control valve 48 is comprised of a diaphragm actuator 52, an on-of f valve 53 driven to be closed by the diaphragm actuator 52, and a reed valve 54 for permitting only the flowing of air toward the exhaust port

44 in tne engine E.
The diaphragm actuator 52 includes a casing 55, a diaphragm
56 having a peripheral edge clamped by the casing 55, and a rod
57 made of a metal and connected at one end to a central portion of the diaphragm 56.
The casing 55 comprises a body 58, and a cover 59 fastened to the body 58 with the peripheral edge of the diaphragm 56 air-tightly clamped therebetween. A negative pressure chamber 60 is defined between the cover 59 and the diaphragm 56, so that one surface of the diaphragm 56 faces into the negative pressure chamber 60, and an atmospheric pressure chamber 61 is defined between the body 58 and the diaphragm 56. A connecting tube 63 having a throttle bore 62 at its tip end is connected to a central portion of the cover 59, and a negative pressure take-off line 64 leading to the inside of the negative pressure chamber 60 through the throttle bore 62 is connected to the connecting tube 63. The negative pressure take-off line 64 is connected to the intake pipe 39 of the intake device 40, as shown in Fig.3. Thus, a negative pressure in the intake pipe 39 is applied to the negative pressure chamber 60.
The rod 57 is axially movably supported by the body 58 and connected at one end directly to a central portion of the diaphragm 56 on the side of the atmospheric pressure chamber
61.
In such diaphragm actuator 52, when the negative pressure in the Intake pipe 39 is raised, the diaphragm 56 is flexed in

a direction to decrease the volume of the negative pressure chamber 60, and the rod 57 Is operated upwards in Fig.5.
The on-off valve 53 includes a valve housing 67, a valve member 68 secured to the other end of the rod 57, and a return spring 69 mounted between the valve housing 67 and the valve member 68.
The valve housing 67 is comprised of the body 58, and a suction cover 70 air-tightly fastened to the body 58. The body 58 Includes an air flow passage 71, a communication bore 72 for permitting the air flow passage 71 to communicate with the atmospheric pressure chamber 61, a valve bore 73 disposed coaxially with the rod 57 and leading to an upstream end of the air flow passage 71, a valve seat 74, into a central portion of which the valve bore 73 opens on the side opposite from the air flow passage 71, and a support tube portion 75 inserted partially and coaxially into the valve bore 73. The rod 57 passing coaxially through the valve bore 73 is axlally slldably fitted into the support tube portion 75.
A valve chest 76 is defined between the body 58 and the suction cover 70. The suction cover 70 is integrally provided with a connecting tube portion 77 leading to the valve chest 76, and the line 78 is connected at its downstream end to the connecting tube portion 77. The line 78 is connected at its upstream end to the secondary air cleaner 79 and further, an air-introducing line 80 leading to an upstream end of the secondary air cleaner 79 is extended forwards along the main

frame 13 up to a point closer to the head pipe 12. Moreover, the secondary air cleaner 79 is disposed on the side opposite from the carburetor 38 with respect to a centerllne C2 passing through a wldthwlse center of the main frame 13.
The valve seat 74 is formed on the body 58 to face Into the valve chest 76, and the valve member 68 is fixedly mounted at the other end of the rod 57 and accommodated in the valve chest 76, so that it can be seated on the valve seat 74.
The return spring 69 Is in the form of a coil surrounding the support tube portion 75 and is mounted between the body 58 and the valve member 68 to exhibit a spring force In a direction to move the valve member 68 away from the valve seat 74, i.e. , in a direction to flex the diaphragm 56 of the diaphragm actuator 52 toward the atmospheric pressure chamber 61.
The reed valve 54 is supported on a valve support plate 82 formed into a disk shape and having a valve bore 81 at its central portion, so that it can open and close the valve bore 81. The valve support plate 82 is air-tightly clamped between the body 58 and a third cover 83 fastened to the body 58 to permit the valve bore 81 to communicate with the downstream of the air flow passage. A valve chest 84 is defined between the third cover 83 and the valve support plate 82, and the reed valve 54 is accommodated in the valve chest 84. A secondary air supply line 86 is connected at its upstream end to a connecting tube portion 85 which is integrally provided on the third cover 83 to lead to the valve chest 84. The secondary air supply line

86 is connected at its downstream end to a lower portion of the cylinder head 42 to lead to the exhaust port 44 in the cylinder head 42 of the engine E.
Moreover, most of the secondary air supply line 86 is disposed on the side opposite from the carburetor 38 with respect to the centerline C2 passing through the wldthwise center of the main frame 13.
Such secondary air control valve 48 is fixed to the main frame 13 of the vehicle body frame assembly F. More specifically, a stay 87 is fastened to a side of the main frame 13, and a support flange 58a integrally provided on the body 58 to abut against the stay 87 from below is fastened to the stay 87.
The fuel tank 25 disposed below the tandem seat 26 and the carburetor 38 disposed in front of and below the fuel tank 25 are connected to each other by a fuel supply line 88 extending forwards and downwards from the fuel tank 25, and a fuel cock 90 of a negative pressure operated type, which is operated by an intake negative pressure in the engine E, is incorporated in an intermediate portion of the fuel supply line 88.
Referring to Fig.6, the fuel cock 90 includes a casing 91, a diaphragm 92 having a peripheral edge clamped by the casing
91, a valve member 93 fixed to a central portion of the diaphragm
92, and a return spring 94 mounted between the casing 91 and the diaphragm 92.
The casing 91 comprises a body 95, and a cover 96 caulked to the body 95 with the peripheral edge of the diaphragm 92

air-tightly clamped therebetween. A negative pressure chamber 97 is defined between the cover 96 and the diaphragm 92, so that one surface of the diaphragm 92 faces into the negative pressure chamber 97. Moreover, a spring-receiving plate 98 is mounted in the negative pressure chamber 97 to abut against an inner surface of the cover 96, and the return spring 94 is mounted under compression between the diaphragm 92 and the spring-receiving plate 98 to exhibit a spring force in a direction of flexing the diaphragm 92 in a direction of Increasing the volume of the negative pressure chamber 97.
The cover 96 is integrally provided with a connecting tube portion 99 leading to the negative pressure chamber 97. The connecting tube portion 99 and the Intake pipe 39 of the intake device 40 are connected to each other by a negative pressure take-off line 100. Thus, a negative pressure in the intake pipe 39 is introduced into the negative pressure chamber 97.
A valve chest 101 is defined between the diaphragm 92 and the body 95. The body 95 is provided with a valve seat 102 on which a valve member 93 secured to a central portion of the diaphragm 92 is seated, and a valve bore 103 which opens at its downstream end into a central portion of the valve seat 102. Moreover, a line section 88a of the fuel supply line 88, which connects the fuel tank 25 and the fuel cock 90 to each other, is connected to the body 95 to lead to the valve bore 103, and a line section 88b of the fuel supply line 88, which connects the carburetor 38 and the fuel cock 90 to each other, is connected

to the body 95 to lead to the valve chest 101.
The intake pipe 39 is integrally provided with a mounting stay 39a overhanging toward the fuel cock 90, and a flange 95a integrally provided on the body 95 of the fuel cock 90 is fastened to a support plate 104 fastened to the mounting stay 39a. In other words, the fuel cock 90 is mounted to the intake pipe 39. In a state in which the fuel cock 90 has been mounted to the intake pipe 39 in this manner, the fuel cock 90 is disposed sideways of the secondary air control valve 48 below the main frame 13 and on the side opposite from the carburetor 38 with respect to the main frame 13.
A bleed air supply line 105 for conducting bleed air to the carburetor 38 is mounted between the air cleaner 37 and the carburetor 38, and a bleed air cleaner 106 is mounted in an Intermediate portion of the bleed air supply line 105, so that it is disposed above the secondary air cleaner 79.
The operation of the present embodiment will be described below. The secondary air control valve 48 for controlling the supplying of the exhaust secondary air to the exhaust port 44 in the engine E disposed below the main frame 13 with the cylinder axis CI inclined forwards is disposed the carburetor 38 of the intake device 40 disposed above the engine E and the cell motor 50 mounted to the upper portion of the engine E and between the engine E and the main frame 13.
Therefore, the secondary air control valve 48 can be disposed effectively in a space created between the engine E

having the cylinder axis CI Inclined forwards and the main frame 13 and between the carburetor 38 and the cell motor 50, respectively. Moreover, the secondary air control valve 48 is disposed in the vicinity of the engine E and hence, the secondary air supply line 86 connecting the secondary air control valve 48 and the exhaust port 44 in the engine E to each other can be shortened.
The secondary air cleaner 79 connected to the secondary air control valve 48 at a location upstream of the secondary air control valve 48 is disposed on the side opposite from the carburetor 38 with respect to the centerline C2 passing through the wldthwlse center of the main frame 13, and the carburetor 38 and the secondary air cleaner 79 can be disposed effectively in the narrow space between the engine E and the main frame 13, so that they are disposed at locations displaced in a widthwise direction of the vehicle body frame assembly F.
Further, since most of the secondary air supply line 86 is disposed on the side opposite from the carburetor 38 with respect to the centerline C2 passing through the widthwise center of the main frame 13, the carburetor 38 and the secondary air supply line 86 can be disposed compactly at locations closer to the main frame 13.
Yet further, the fuel cock 90 of the negative pressure operated type incorporated in an intermediate portion of the fuel supply line 88 for supplying fuel to the carburetor 48 is disposed sideways of the secondary air control valve 48 below

the main frame 13 and disposed sideways of the secondary air control valve 48 disposed between the carburetor 38 and the cell motor 50. Therefore, the fuel cock 90 can be disposed In proximity to the carburetor 38, and the negative pressure take-off line 100 for conducting the negative pressure from the intake device 40 to the fuel cock 90 can be shortened.
Since the fuel cock 90 Is disposed on the side opposite from the carburetor 38 with respect to the main frame 13, it is possible to facilitate the arrangement of the fuel supply line 88 and the negative pressure take-off line 100.
Moreover, since the fuel cock 90 is incorporated in an intermediate portion of the fuel supply line 88 extending forwards and downwards from the fuel tank 25 and connected to the carburetor 38, even if the air enters the line section 88b of the fuel supply line 88 connecting the carburetor 38 and the fuel cock 90 to each other with the stoppage of the supplying of the fuel from the fuel tank 25, the fuel can be filled quickly into the line section 88b during subsequent supplying of the fuel, even if an operation for withdrawing the air from the line section 88b is omitted. Thus, it is possible to quickly supply the fuel to the carburetor 38, while eliminating the need for a part such as a relief valve for withdrawing the air to enable a reduction in number of parts.
Further, since the fuel cock 90 is mounted to the intake pipe 39 of the intake device 40, the degree of freedom for the disposition of the fuel cock 90 can be increased, as compared

with a system in which a fuel cock 90 is mounted to a fuel tank 25.
Although the embodiment of the present invention has been described in detail, it will be understood that the present invention is not limited to the above-described embodiment, and various modifications in design may be made without departing from the spirit and scope of the invention defined In claims.
1


WE CLAIM:
1. A fuel cock-mounting structure in a motorcycle, the motorcycle comprising
an engine (E) suspended on a vehicle body frame assembly (F) comprising a main
frame (13) extending in a rearward declined manner from a head pipe (12), the engine
being disposed below said main frame (13); an air cleaner (37) and a carburetor (38)
disposed above said engine (E); and a fuel cock (90) of a negative pressure operated
type operated by an intake negative pressure in the engine (E), the fuel cock being
incorporated in an intermediate portion of a fuel supply line (88) which connects a
fuel tank (25) disposed below a riding seat (26) supported at a rear portion of the
vehicle body frame assembly (F) and said carburetor (38) to each other, the fuel cock-
mounting structure being characterized in that said fuel cock (90) incorporated in an
intermediate portion of said fuel supply line (88) extending in a forward declined
manner from said fuel tank (25) and connected to said carburetor (38) is mounted to
an intake pipe (39) which connects said carburetor (38) and the engine (E) to each
other.
2. The fuel cock-mounting structure in a motorcycle as claimed in claim 1,
wherein said fuel cock (90) is mounted to a mounting stay (39a) integrally provided
on said intake pipe (39).
3. The fuel cock-mounting structure in a motorcycle as claimed in claim 1,
wherein said fuel cock (90) is disposed on a side opposite from said carburetor (38)


Documents:

1106-chenp-2004 abstract-duplicate.pdf

1106-chenp-2004 abstract.pdf

1106-chenp-2004 claims-duplicate.pdf

1106-chenp-2004 claims.pdf

1106-chenp-2004 correspondence-others.pdf

1106-chenp-2004 correspondence-po.pdf

1106-chenp-2004 description (complete)-duplicate.pdf

1106-chenp-2004 description (complete).pdf

1106-chenp-2004 drawings-duplicate.pdf

1106-chenp-2004 drawings.pdf

1106-chenp-2004 form-1.pdf

1106-chenp-2004 form-19.pdf

1106-chenp-2004 form-26.pdf

1106-chenp-2004 form-3.pdf

1106-chenp-2004 form-4.pdf

1106-chenp-2004 form-5.pdf

1106-chenp-2004 pct search report.pdf

1106-chenp-2004 pct.pdf

1106-chenp-2004 petition.pdf


Patent Number 202060
Indian Patent Application Number 1106/CHENP/2004
PG Journal Number 05/2007
Publication Date 02-Feb-2007
Grant Date 11-Sep-2006
Date of Filing 18-May-2004
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA
Applicant Address 1-1, MINAMI-AOYAMA 2-CHOME, MINATO-KU, TOKYO 107-8556,
Inventors:
# Inventor's Name Inventor's Address
1 HIWATASHI, DAI C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1, CHOU 1-CHOME, WAKO-SHI, SAITAMA 351-0193
PCT International Classification Number F02M37/00
PCT International Application Number PCT/JP01/09213
PCT International Filing date 2001-10-19
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 PCT/JP01/09213 2001-10-19 PCT