JPH0781655A - Rear wheel suspension device for motorcycle - Google Patents

Abstract

PURPOSE:To improve the degree of freedom in layout of parts without deteriorating air intake efficiency or without enlarging a car width. CONSTITUTION:A shock absorbing spring to relieve a shock applied to a rear wheel 26 from a road surface is arranged in the longitudinal direction of a vehicle under an engine 12 as a belt-like leaf spring 31, and a cylinder piston type cylindrical damper 30 to restrain vertical vibration of the rear wheel 26 is arranged in the vertical direction in a central part of a car body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel suspension system for a motorcycle, and more particularly, to an improvement in the disposition structure of the suspension system including a tubular damper.

[0002]

2. Description of the Related Art In a motorcycle, a rear wheel suspension provided between a rear arm and a vehicle body arm is provided with a buffer spring for absorbing a shock applied to the rear wheel from a road surface and a damper for suppressing irregular vertical vibration of the rear wheel. The device is installed. As this rear wheel suspension device, it is general that an integrated shock absorber in which a coil spring and a telescopic tubular damper are coaxially arranged is arranged vertically.

[0003]

However, in the above-mentioned conventional apparatus, as a result of integrally disposing the coil spring and the tubular damper, there is a problem that the exclusive space of the entire shock absorber in the central portion of the vehicle body becomes large. Especially, when a large-diameter coil spring is used to secure a large allowable load, a larger occupied space is required. As a result, it becomes difficult to arrange the intake duct (air cleaner joint) that connects the carburetor and the air cleaner in a straight line, which may cause a problem that the intake efficiency decreases. On the other hand, if the intake duct is forced to be linear, the vehicle width near the thigh of the occupant becomes wider. Thus, in the above conventional device,
Low degree of freedom in component layout.

The present invention has been made in view of the above circumstances, and a rear wheel suspension system for a motorcycle capable of improving the degree of freedom in component layout without lowering intake efficiency or increasing vehicle width. Is intended to provide.

[0005]

In the rear wheel suspension system for a motorcycle according to the present invention, a buffer spring for cushioning a shock applied to the rear wheel from the road surface is directed to the lower side of the engine in the vehicle front-rear direction as a strip-shaped plate spring. It is characterized in that a cylinder-piston type cylindrical damper that suppresses vertical vibration of the rear wheel is arranged vertically in the center of the vehicle body.

[0006]

In the present invention, since the buffer spring is a strip-shaped plate spring and is arranged below the engine in the front-rear direction of the vehicle, the rear wheel suspension arranged at the center of the vehicle body is only the cylindrical damper. . As a result, the space occupied by the rear wheel suspension device in the center of the vehicle body can be reduced. As a result, the intake duct that connects the carburetor and the air cleaner can be arranged in a straight line, and the intake efficiency can be improved. Further, the width of the vehicle can be reduced, and thus the degree of freedom in component layout can be improved.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 11 are views for explaining a rear wheel suspension system of a motorcycle according to an embodiment of the present invention,
1 is a left side view of a motorcycle, FIG. 2 is an enlarged partial view of a cylindrical cylinder of a rear wheel suspension device and its peripheral portion, FIG. 3 is a sectional plan view of a link mechanism of the rear wheel suspension device, and FIG. IV of 1
-IV line arrow view, FIGS. 5 to 9 are views for explaining the pillow of the leaf spring and the mounting portion thereof constituting the above-mentioned rear wheel suspension device, and FIGS. 10 and 11 are initial load adjusting mechanism of the leaf spring. It is a figure for explaining.

In these drawings, reference numeral 1 denotes a motorcycle equipped with the device of this embodiment. The motorcycle 1 has a front fork (not shown) formed by a head pipe 3 of a body frame 2.
A rear arm 21 that rotatably supports the left and right and that supports the rear wheel 26 by the left and right rear arm brackets 5 and 5 '.
And an engine 12 mounted in a cradle of the vehicle body frame 2. A fuel tank 10 is provided above the engine 12 and a seat 11 is provided behind the tank 10.
It has a structure in which each is mounted. In addition, 14a,
14b and 14c are a vaporizer, an ecliner,
And an air cleaner joint (intake duct) connecting them, and 73 is a radiator.

The body frame 2 is of a so-called semi-double cradle type, and is connected to the head pipe 3, a tank rail 4 extending obliquely rearward and downward from the head pipe 3, and a rear end portion of the tank rail 4. It is composed of left and right rear arm brackets 5, 5 ', and a down tube 6 for connecting the lower ends of the rear arm brackets 5, 5'to the head pipe 3. In addition, 8, 9
Is a seat rail and a back stay which are integrated with each other, and these are detachably bolted to the tank rail 4 and the rear arm brackets 5 and 5 '.

Each of the rear arm brackets 5 and 5'has a rectangular cross section in which the left and right halves made of sheet metal are butted against each other and welded. The left and right rear arm brackets 5, 5'are welded to each other by a lower cross pipe 5c made of a round pipe.

The down tube 6 comprises a single center tube 6b made of a rectangular pipe, and a left end at the lower end thereof.
It is composed of two side tubes 6a made of rectangular pipes connected so as to branch to the right. The upper end of the center tube 6b is welded to the head pipe 3, and the rear end of each side tube 6a is welded to the lower cross pipe 5c.

The engine 12 is of a water-cooled, two-cycle, single-cylinder type, and has a cylinder block 14 and a cylinder head 15 laminated and fastened in a forwardly inclined state on a front portion of a crankcase 13 integrated with a transmission case. It has a structure. The engine 12 is mounted on the single frame 2 with the following structure. The front portion and the bottom boss portions 13a and 13b of the crankcase 13 are bolted to the support brackets 61 and 6c fixed to the rising portion and the bottom portion of the side tube 6a, respectively. Further, the rear boss portion 13c of the crankcase 13 is supported by the pivot shaft 27 of the rear arm 21. Further, the suspension boss portion 15a of the cylinder head 15 is fixed to the tank rail 4 side via the suspension bracket 15b.

A rear wheel suspension device 29 is arranged from the rear side of the tank rail 4 to the lower side of the engine 12.
The rear wheel suspension device 29 is arranged between the tank rail 4 and the rear arm 21, and is a cylinder / piston type tubular damper 30 that suppresses irregular vertical vibration of the rear wheel 26.
And a leaf spring 31 made of, for example, glass fiber, which is disposed between the rear arm 21 and the Dunun tube 6 of the vehicle body frame 2 and reduces the shock applied to the rear wheel 26 from the road surface. The link mechanism 56 connects the damper 30 and the rear arm 21. The damper 3 is provided on the right side of the damper 30.
A reservoir tank 40 for absorbing an expansion amount due to a temperature rise of the hydraulic oil housed in 0 is arranged.

An upper end portion of the cylinder body 32 of the damper 30 is rotatably connected to a bracket 78 which is welded and fixed to a substantially central portion of the tank rail 4 and a lower end of a piston rod 36 of the damper 30. Is connected to a connecting rod 37. On the other hand, the left and right arm bodies of the rear arm 21 are fixed to each other by a rectangular frame 33 extending in the vehicle width direction, and upper and lower brackets 34 and 35 are welded and fixed to the upper and lower end surfaces of the rectangular frame 33, respectively. Has been done.

In FIG. 4, reference numeral 32 denotes the cylinder body of the damper 30, and the chain double-dashed line 39 is the outline of the coil spring on the assumption that the coil spring is mounted around the damper 30. Shows. In addition, the two-dot chain line 14
Reference character c'denotes an air cleaner joint when the coil spring is mounted. In this way, when the coil spring 39 is integrally mounted around the damper 30, the space occupied by the entire damper 30 in the central portion of the vehicle body becomes large. Then, when a large-diameter coil spring is used to secure a large allowable load, or when the reservoir tank 40 as described above is used.
In the case of arranging, a larger occupied space is required. As a result, the air cleaner joint 14c 'is bent, and it becomes difficult to arrange the air cleaner joint 14c' in a straight line, which may cause a problem that the intake efficiency is reduced. On the other hand, if the air cleaner joint 14c 'is forced to be straightened, the damper has to be displaced to the right side, resulting in a wider vehicle width near the thighs of the occupant. As described above, when the coil spring 39 is mounted around the damper 30, restrictions on the component layout are large.

On the other hand, in this embodiment, since the rear wheel suspension device 29 arranged in the central portion of the vehicle body is only the cylindrical damper 30, the space occupied by the rear wheel suspension device 29 in the central portion of the vehicle body can be reduced. . As a result, the vaporizer 14a
The air cleaner joint 14c for connecting the air cleaner 14b and the air cleaner 14b can be arranged linearly, and the intake efficiency can be improved. Also, the width of the car can be reduced,
In this way, the degree of freedom in component layout can be improved. Further, since the leaf spring 31 is arranged below the engine and most of the load applied to the rear wheel 26 is received by the leaf spring 31, the load applied to the damper 30 itself is not so large. Therefore, it is possible to offset the damper 30 from the center of the vehicle body to the right side (upward in FIG. 4), which can further improve the degree of freedom in component layout.

Plates 42 and 43 are bolted to the upper and lower surfaces of the rear end portion 31a of the leaf spring 31, respectively. The lower plate 43 extends further rearward than the rear end portion 31a of the leaf spring 31, and a bracket 43a is provided on the extended portion. As shown in FIG. 3, bolts 45 are inserted into the brackets 43a and fixed by tightening nuts.
A bolt 46 is inserted into and fixed with a nut. A connecting collar 6 is attached to each of the bolts 45 and 46.
4, 65 are fitted. Also, each bracket 43
A spring link 50 is arranged between a and 35, and each end of the spring link 50 is rotatably connected to the connecting collars 64 and 65 via bearings 66 and 67. That is, upper and lower pivot parts of the spring link 50 are formed by the mounting portions of the bolts 46 and 45.

Further, the end portion of the leaf spring 31 is located above the mounting portion of the bolt 45 which constitutes the lower end pivot portion of the spring link 50 (see FIG. 2), which increases the ground height of the vehicle body. Can be maintained. Conversely speaking, since the lower end pivot portion is arranged below the end portion of the leaf spring 31, the total length (link length) of the spring link 50 can be made longer, whereby the leaf spring 31 Rear end 31a
The change in the direction of the force acting on can be reduced.

A pillow 80, which serves as a fulcrum for the deformation of the leaf spring 31 as the rear arm 21 moves up and down, is disposed above the leaf spring 31 in the longitudinal center thereof. The pillow 8
Reference numeral 0 denotes an elastic body such as hard rubber, and as shown in FIGS. 5 to 9, a contact portion 81 (see FIG. 9) with which the leaf spring 31 (see the chain double-dashed line in FIG. 9) at the time of deformation contacts from below. And a protruding portion 82 which is formed on the left and right sides of the corresponding contact portion 81 so as to project downward and sideways and covers both side portions of the leaf spring 31.
(See FIGS. 5 and 6).

The abutting portion 81 is bolted and fixed to a bracket 84 that is installed between the left and right side tubes 6a, 6a, and the abutting surface 81a of the abutting portion 81 that abuts the leaf spring 31 is fixed. For example, it has an arc shape that is bent in the front-rear direction of the vehicle body with a curvature R. The contact surface 81a
Is not limited to one curvature, and may be configured with two or more curvatures. By configuring the corresponding contact surface 81a with a plurality of curvatures in this way, it is possible to change the spring characteristics when the leaf spring 31 is deformed so-called progressively.
On the other hand, the central portion in the longitudinal direction of the lower cross pipe 5c is formed in a semicircular cross section (see FIGS. 5 and 9), and the rear edge of the contact portion 81 is the lower surface of the semicircular portion 5c '. Is in contact with. Further, the overhanging portion 82 is in contact with each of the side tubes 6a from below.

Here, the damper 30, the link mechanism 56,
When disposing the leaf spring 31 and the pillow 80, when one occupant is on board, that is, when 1G,
The action direction of the load acting on the rear end portion 31a of the leaf spring 31 (link pulling direction) is set to be substantially perpendicular to the axis of the leaf spring 31. As a result, the above 1G
It is possible to make the ride comfort at that time soft.

The leaf spring 31 is fitted with a box-shaped lower cover 86 that covers the bottom and both sides of the leaf spring 31, so that the leaf spring 31 can be protected from the splashing of small stones during traveling. The lower cover 86 is made of, for example, an elastic member made of resin. Also, the lower cover 86
Slits 88 are formed at the rear end sides of both side portions 87 of the two side portions 87, whereby a part of the rear end sides of the both side portions 87 is formed into a bifurcated upper portion 8.
9 and the lower part 90. The upper portions 89 are connected to each other by a connecting portion 89b arranged on the upper surface of the leaf spring 31. In addition, the front end side 8 of the both side portions 87
Similarly, 7a are connected to each other by a connecting portion 87b arranged on the upper surface of the leaf spring 31. Further, a part of the upper portion 89 is extended upward and forward of the vehicle body (leftward in FIG. 9) in an arc shape, and the pillow 8 is extended by the extension portion 89a.
The opening of the wedge-shaped space A between the contact portion 81 of 0 and the leaf spring 31 is covered. With this configuration, the leaf spring 31
When is deformed in the vertical direction, the upper portion 89 is opened and closed in accordance with this deformation, and the wedge-shaped space A is always covered by the extension portion 89a.

On the front end 31b of the leaf spring 31,
A bracket 95 and a plate 96 are respectively arranged on the lower surface, and the bracket 95 and the plate 96 are attached to the front end portion 31b by bolts 97 that pass through them. The bracket 95 is formed with a pair of elongated holes 95a extending substantially vertically. On the other hand, between the left and right side tubes 6a, bolts 98 that pass through the elongated holes 95a are arranged and fixed to the side tubes 6a. A collar 99 is fitted in a substantially central portion of the bolt 98, and a boss portion 100a of an adjusting bolt 100 is fitted in the collar 99. This adjustment bolt 10
An adjusting nut 101 is screwed on the end portion of 0. By appropriately adjusting the tightening amount of the adjusting nut 101, the leaf spring 31 is inserted through the bracket 95 and the plate 96.
The front end portion 31b of the leaf spring 31b rises, which causes the leaf spring 31
The initial load of can be adjusted. Here, the disposing direction of the adjusting bolt 100, that is, the adjusting direction of the initial load of the leaf spring 31 (direction of arrow a) is with respect to the line f connecting the center of the bolt 98 and the leaf spring supporting point 102 of the pillow 80. It is set in a substantially right angle direction. This allows
It is possible to avoid applying a longitudinal force to the leaf spring 31 when adjusting the initial load.

Next, the operation of the rear wheel suspension device 29 will be briefly described. When the rear wheel 26 rides on a convex portion of the road surface, for example, the rear arm 21 rises due to the impact force,
Along with this, the rear end portion 31a of the leaf spring 31 has the spring link 5
Pulled up through 0. As a result, the leaf spring 31 bends around the pillow 80 as a fulcrum, and the impact force is alleviated according to the spring constant of the leaf spring 31 in the bending direction.

Further, as the rear arm 21 is raised and lowered, the connecting rod 37 is rotated and moved up and down via the upper end pivot portion of the upper bracket 34. This makes damper 3
The piston rod 36 of 0 moves up and down to generate a damping force, and the irregular vertical vibration of the rear wheel 26 is suppressed.

As described above, according to this embodiment, the strip plate-shaped leaf spring 31 is used as a buffer spring for cushioning the shock applied to the rear wheels from the road surface, and the leaf spring 31 is directed downward in the engine in the longitudinal direction of the vehicle. Since the cylinder-piston-type tubular damper 30 for suppressing the vertical vibration of the rear wheels is arranged in the central portion of the vehicle body in the vertical direction, it is arranged in the central portion of the vehicle body of the rear wheel suspension device 29. Is a cylindrical damper 30
Will only be. As a result, the space occupied by the rear wheel suspension device 29 in the central portion of the vehicle body can be reduced, and as a result, the intake duct 14c connecting the carburetor 14a and the air cleaner 14b is made linear as compared with the case where a coil spring damper is adopted. It is possible to arrange them and improve the intake efficiency. Further, the width of the vehicle can be reduced, and thus the degree of freedom in component layout can be improved.

In the above embodiment, the end portion of the connecting rod 37 connected to the piston rod 36 of the damper 30 is
Although the bracket 34 is connected to the upper portion of the rectangular frame 33, the application of the present invention is not limited to this. For example, as shown in FIG. 12, the rear end portion 3 of the leaf spring 31 is
The bracket 110 may be formed on the plate 42 on the la 1a, and the end portion of the connecting rod 37 may be connected to the bracket 110. In FIG. 12, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts. In this case,
When the leaf spring 31 is fully extended, the rear end portion of the leaf spring 31 is supported via the damper 30, and the impact force can be relieved by the elastic force of the leaf spring 31. Further, since the mounting position of the damper 30 can be lowered, a space can be generated below the seat, and the seat height can be lowered by utilizing the space.

In the above embodiment, the lower cover 86 covers the opening of the wedge-shaped space A between the contact portion 81 of the pillow 80 and the leaf spring 31. Instead of FIGS.
You may adopt what is shown in. In these figures, the same reference numerals as those in the above-mentioned embodiment indicate the same or corresponding parts. In the structure shown in FIG. 13, the lower cover 86 is simplified to leave only the connecting portion 89 corresponding portion 89b ′ and the extending portion 89a corresponding portion 89a ′, and the connecting portion corresponding portion 89b ′ of the leaf spring 31. It is attached to the top surface. Also in this case, similarly to the above-mentioned embodiment, the extension-corresponding portion 89a 'moves in the vertical direction as the leaf spring 31 deforms, whereby the wedge-shaped space A is always covered. In this case, a member for covering the side and the lower side of the leaf spring 31 may be separately attached to the leaf spring 31.

Further, in the structure shown in FIG. 14, a bag-shaped member 110 made of an elastic member such as rubber is disposed at the rear end side of the pillow 80, and the end portion of the bag-shaped member tool 110 has the pillow. It is fixed to the end face of the overhanging portion 82 of 80. Further, a pressing plate 112 for pressing the bag-shaped member fixing portion from below is attached to the lower surface of the plate spring 31. An opening 111 is formed in a substantially central portion of the bag-shaped member 110.
The leaf spring 31 is inserted through the inside of the shaft 11.

Further, in FIGS. 15 and 16, a tubular member 122 having a shape surrounding the deformation area of the leaf spring 31 is provided, and a rear end opening 122a of the tubular member 122 is provided with a bellows-like member 120 such as rubber. It is covered by. An opening 121 is formed in the bellows member 120, and the leaf spring 31 is inserted through the opening 121.

[0031]

As described above, according to the rear wheel suspension system for a motorcycle according to the present invention, a buffer spring for cushioning a shock applied from the road surface to the rear wheel is used as a strip-shaped plate spring in the vehicle longitudinal direction below the engine. The cylinder-piston type tubular damper that suppresses vertical vibration of the rear wheels is arranged vertically in the center of the vehicle body, so the air cleaner joint can be made linear and the intake efficiency can be improved. Further, there is an effect that the vehicle width can be reduced, and thereby the degree of freedom in component layout can be improved.

[Brief description of drawings]

FIG. 1 is a left side view of a motorcycle including a rear wheel suspension system according to an embodiment of the present invention.

FIG. 2 is an enlarged partial view of a cylindrical cylinder of the rear wheel suspension device and its peripheral portion.

FIG. 3 is a sectional view of a link mechanism of the rear wheel suspension device.

FIG. 4 is a view taken along the line IV-IV of FIG.

FIG. 5 is a diagram for explaining a pillow of a leaf spring and its mounting portion which constitute the rear wheel suspension device.

6 is a view taken along the line VI-VI of FIG.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a plan view of a lower case that protects the leaf spring.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is a side view of the initial load adjusting mechanism of the leaf spring.

11 is a partial cross-sectional view taken along the line XI-XI of FIG.

FIG. 12 is a diagram showing a modified example of FIG.

FIG. 13 is a diagram showing a first modification example of FIG. 9.

FIG. 14 is a diagram showing a second modification of FIG. 9.

FIG. 15 is a diagram showing a third modification example of FIG. 9;

16 is a view taken along the line XVI-XVI in FIG.

[Explanation of symbols]

 1 Motorcycle 12 Engine 26 Rear Wheel 29 Rear Wheel Suspension 30 Damper 31 Leaf Spring

Claims (1)

[Claims] 1. A cylinder-piston type, in which a buffer spring for reducing a shock applied to a rear wheel from a road surface is arranged as a strip plate-shaped leaf spring in a vehicle front-rear direction below an engine and a vertical vibration of a rear wheel is suppressed. A rear-wheel suspension system for a motorcycle, wherein the cylindrical damper is disposed in the center of the vehicle body in the vertical direction.