JPH05178264A - Rear wheel suspension device for motorcycle - Google Patents

Abstract

PURPOSE:To improve the space efficiency, adjust the initial load of a leaf spring by the simple operation, and prevent an unreasonable load from being applied on the leaf spring. CONSTITUTION:The rear wheel suspension device for a motorcycle is equipped with a buffer spring for softening the shock applied to a rear wheel from a road surface and a damper for suppressing the irregular vertical vibration of the rear wheel and is interposed between a rear arm and a car body fixing part. In this case, the buffer spring is formed of a strip plate shaped leaf spring 31 and arranged under the engine, and the front edge part 31b of the leaf spring 31 is supported by a body frame 6 through a pivotal supporting mechanism 47, and the rear edge part 31a is supported by a rear arm 20 through a link mechanism 56. Pillows 63 and 63 for bending the leaf spring 31, accompanied with the rise of the rear arm 20 are arranged at the near center in the longitudinal direction of the leaf spring 31. Further, an initial load adjusting mechanism 37 for adjusting the interval between the leaf spring 31 and the body frame 6 is installed on the pivotal supporting mechanism 47.

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, when a leaf spring is used as a buffer spring, the arrangement position and structure of a mechanism for applying an initial load to the leaf spring. Regarding the improvement of.

[0002]

2. Description of the Related Art Conventionally, a rear wheel suspension system for a motorcycle has a structure in which a shock absorber composed of a coil spring and a telescopic tubular damper is interposed between a rear arm and a vehicle body frame. And recently, with one shock absorber,
It is general to employ a structure in which this is arranged directly or through a link mechanism between a portion near the pivot portion of the rear arm and a lower portion of the fuel tank of the vehicle body frame or a lower portion of the seat ( For example, JP-A-59-120
585).

However, in the above conventional device, the shock absorber occupies the space for arranging the parts located in the center of the vehicle, which makes it difficult to secure a space for arranging other on-vehicle parts such as the air cleaner and the battery. There is a problem of poor space efficiency.

[0004]

On the other hand, the present inventors are currently studying to employ a leaf spring instead of the coil spring. In this structure, it is desirable to provide a mechanism capable of adjusting the initial load of the leaf spring to a desired value. However, depending on the arrangement position of this adjusting mechanism or the structure, the adjustment work is troublesome, or the leaf spring is further added. There is a concern that an unreasonable load will act on it.

The present invention has been made in view of the above-mentioned conventional problems and problems when a leaf spring is adopted, and it is possible to improve space efficiency and adjust the initial load of the leaf spring by a simple operation. Moreover, it is an object of the present invention to provide a rear wheel suspension device for a motorcycle in which an unreasonable load does not act on the leaf spring.

[0006]

SUMMARY OF THE INVENTION The present invention is provided with a buffer spring for reducing a shock applied to a rear wheel from a road surface, and a damper for suppressing irregular vertical vibration of the rear wheel, and is provided between a rear arm and a vehicle body fixing portion. In the rear wheel suspension system of a motorcycle provided in the above, the buffer spring is arranged below the engine as a strip plate-shaped leaf spring, and the front end portion of the leaf spring is supported by a vehicle body fixing portion via a pivotal support mechanism. The rear end is supported by the rear arm via a link mechanism, and a fulcrum that bends the leaf spring as the rear arm rises is disposed substantially in the center of the leaf spring in the longitudinal direction. At least one of the link mechanisms is provided with an initial load adjusting mechanism capable of adjusting the distance between the leaf spring and the vehicle body fixing portion or the rear arm.

[0007]

According to the rear wheel suspension system of the present invention, the initial load capable of adjusting the distance between the front end of the leaf spring and the vehicle body frame or the engine (vehicle body fixing portion) or the distance between the rear end and the rear arm. Since the adjusting mechanism is provided, the initial load of the leaf spring can be set to a desired value by a simple operation of adjusting the interval. In this case, since the leaf spring faces the outside of the vehicle body and the initial load adjusting mechanism is arranged at the front end portion or the rear end portion of the leaf spring, the adjusting mechanism can be easily operated from the outside. From the point of view, adjustment work is easy.

Further, since the front end portion and the rear end portion of the leaf spring are supported through the pivotal support mechanism or the link mechanism, the leaf spring is bent and deformed as the rear arm is raised, and the front and rear end portions thereof are bent. When the angle of changes, the corresponding pivot mechanism,
The link mechanism swings back and forth to absorb the angle change.
As a result, it is possible to prevent an unfavorable bending force from acting on the front end portion and the rear end portion of the leaf spring, reduce the tension force in the length direction of the leaf spring, and prevent an unreasonable load from acting on the leaf spring. It can be suppressed and the durability of the leaf spring can be secured.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 are views for explaining a rear wheel suspension system of a motorcycle according to an embodiment of the present invention. FIG. 1 is a side view, FIG. 2 is a plan view, and FIGS. III-III line sectional view, IV-IV line sectional view, FIGS. 5 and 6 are a side view and a sectional front view of the initial load adjusting mechanism of the leaf spring, and FIG. 7 is a left side surface of a motorcycle equipped with the embodiment apparatus. It is a figure.

In the drawing, reference numeral 1 is a motorcycle to which the suspension system of the embodiment is adopted. The vehicle body frame 2 of the motorcycle 1 is of a so-called semi-double cradle type and has the following structure. The front end of the front half portion 4a of the tank rail 4 is connected to the head pipe 3, and the rear arm bracket 5 is connected to each rear end of the rear half portion 4b. Also, at the lower end of the rear arm bracket 5, the left side of the down tube 6,
The rear end of the right branch portion 6a is connected, and the front half portion 6b of the down tube 6 formed of one square pipe is connected to the head pipe 3. Further, it has a structure in which the vicinity of the branch point of the tank rail 4 and the front half portion 6b of the down tube 6 are connected by a reinforcing tension pipe 7 made of one round pipe. The tank rail 4 is 2
The first half of the rectangular pipe of the book is overlapped and joined in the vehicle width direction, and the second half is separated. The left and right rear arm brackets 5 are connected by an upper cross pipe 5b and a lower cross pipe 5c. Further, 8 is a seat rail, and 9 is a back stay that supports a rear end portion of the seat rail 8.

A fuel tank 10 is provided on the tank rail 4 of the vehicle body frame 2, and a seat 11 is provided on the seat rail 8.
However, an engine 12 is mounted in each cradle composed of the tank rail 4, the rear arm bracket 5, and the down tube 6.

The engine 12 is a water-cooled two-cycle single-cylinder type engine, and a cylinder block 14 and a cylinder head 15 are laminated and fastened to the front of a crankcase 13 integrated with a transmission case in a forwardly inclined state. It has a structure. The engine 12 is mounted on the vehicle body frame 2 with the following structure. The front and bottom bosses 13a and 13b of the crankcase 13 are bolted to the support bracket 61 that is bolted to the rising portions of the left and right branch portions 6a of the down tube 6 and the bracket 6c that is welded and fixed to the bottom. Fix it. The rear boss portion 13c of the crankcase 13 is supported by a pivot shaft 27 described later. Further, the suspension boss portion 15a of the cylinder head 15 is bolted and fixed to the tank rail 4 via the suspension bracket 15b.

The support bracket 61 is shown in FIG.
As shown in FIG. 6, left and right flange portions 61a having a substantially triangular shape in a side view are integrally connected to each other by upper and lower connecting portions 61b and 61c.
On the left side of the down tube 6 with a pair of upper and lower bolts 61d,
It is fixed to the right branch portion 6a.

A rear arm 21 is pivotally supported by the rear arm bracket 5 so as to be vertically swingable. The rear arm 21 has a pivot part 23 formed at the front ends of a pair of left and right prismatic arm bodies 22a and 22b, and the rear parts of the pivot parts 23 of the arm bodies 22a and 22b are formed into a prismatic cross member. A rear wheel 26 is pivotally supported by an axle 25 that is fixedly inserted and fixed between the rear ends of the left and right arm bodies 22a and 22b. The pivot portion 23 is axially supported by a pivot shaft 27 inserted through the bearing through a bearing, and the pivot shaft 27 is fixed to the left and right rear arm brackets 5 with a nut 27a. The rear boss portion 13c of the crankcase 13 is located between the left and right pivot portions 23, 23.

A rear wheel suspension device 29 is arranged from the front part of the rear arm 21 to the lower part of the engine 12. The rear wheel suspension device 29 is disposed between the rear arm 21 and the rear arm bracket 5, and is provided with a rotary damper 30 for suppressing irregular vertical vibration of the rear wheel 26, the rear arm 21 and the body frame 2. A leaf spring 31 that is arranged between the Dunun tube 6 and reduces the shock applied to the rear wheel 26 from the road surface, and a link mechanism 56 that connects the leaf spring 31, the damper 30 and the rear arm 21.
It consists of and.

The rotary damper 30 includes a case body 32.
A substantially plate-shaped wing-shaped piston 33 that defines two chambers in the case is housed and arranged in a damper case 32 that is substantially fan-shaped in a side view and is composed of a and a lid 32b.
The rotary shaft 34 is inserted into the shaft a and is spline-fitted, and the rotary shaft 34 is rotatably supported by the damper case 32. Although not shown, the lid 32b is formed with a plurality of oil passages that communicate the two chambers defined by the piston 33, and a throttle mechanism is arranged in the passages. When the piston 33 is rotated around the rotary shaft 34, the hydraulic oil moves from one chamber through the throttle mechanism to the other chamber, and this damper 30 generates a damping force.

The damper case 32 has upper and lower boss portions 3
2d and 32e are integrally formed, and both boss portions 32 are formed.
d and 32e are fixed to the support brackets 36a and 36b with fixing bolts 35a and 35b. The support brackets 36a and 36b are respectively attached to the upper cross pipe 5
b, fixed to the lower cross pipe 5c by welding.

The link mechanism 56 includes a pair of left and right damper arms 37 that rotationally drive the piston 33 of the damper 30, and a pair of left and right intermediate links 38 that connects the arm 37 and the rear arm 21. A pair of left and right spring links 3 connecting the intermediate link 38 and the leaf spring 31.
9 and 9.

The left and right intermediate links 38 are plate-shaped bodies having a substantially triangular shape in a side view, and have first and second connecting holes 38a,
38b, the first and second connecting bolts 38c, 38
d and a nut 38e are integrally connected. Note that 38f and 38g are first and second connecting collars that regulate the dimension between the intermediate links 38 and 38.

A support bracket 24a fixed to the lower surface of the cross member 24 is connected to the first connecting collar 38f via a bearing 24b, so that the intermediate link 38 can be vertically swung by the rear arm 21. It is supported.

The lower ends 37a of the pair of left and right damper arms 37 are rotatably connected to the second connecting collar 38g via bearings. Incidentally, 37b, 37c
Are bolts and nuts for fastening the left and right damper arms 37 together. Upper end 3 of the damper arm 37
7d is spline-fitted to the outward protruding end of the rotary shaft 34 of the damper 30 and is fixed by tightening the nut. This causes the damper arm 37 to rotate the piston 33 of the damper 30 as the rear arm 21 swings. Further, the presence of the damper arm 37 causes the intermediate link 38 to rotate around the first connecting bolt 38c.

Further, connecting pins 38h are provided on the outer surface of the intermediate link 38 in a protruding manner, and the upper ends 39a of the left and right spring links 39 are connected to the respective pins 38h via bearings. The lower ends 39 of the left and right spring links 39
The left and right support pins 43a of the rear spring bracket 43 are inserted in b through bearings.
The rear end portion 31a of the leaf spring 31 is bolted and fixed to the support portion 43b of No. 3.

Further, above the leaf spring 31 substantially in the center in the longitudinal direction, the leaf spring 31 accompanying the vertical movement of the rear arm 21 is provided.
Front and rear pillows 62 and 63, which serve as fulcrums for the deformation, are arranged so that their longitudinal positions can be adjusted.

The front pillow 62 connects a pair of left and right side plates 62a, each of which has a large number of mounting screw holes 62c arranged in a row in the front-rear direction, with a base plate 62b, and a lower surface of the base plate 62b. A block 62d made of an elastic material such as relatively hard rubber or foamed urethane is attached to the. The side plate 62a is fixed by fixing bolts 62e near the connecting portion of the left and right branch portions 6a with the bracket body 5a by selecting the front-rear direction position. The size and mounting position of the block 62d of the front pillow 62 are set so as to contact the upper surface of the leaf spring 31 even at the rear arm lowermost position shown in FIG.

The rear pillow 63 has a block 6 made of the same material as the front block 62d on the lower surface of the base plate 63a.
3b is attached. And the base plate 6
3a is fixed by screwing the fixing bolt 63c into one of the mounting screw holes 63e of the mounting plate 63d fixed to the connection point between the branch portion 6a and the lower cross pipe 5c, by selecting its longitudinal position. ing. This rear pillow 6
3, the respective dimensions and mounting positions are set so that the leaf spring 31 contacts the rubber block 63b from the time when the rear arm 21 is lifted by a predetermined amount.

The front end portion 31b of the leaf spring 31 is connected to the vehicle body frame 2 via a pivot support mechanism 47 including a front spring bracket 47a and a support bolt 59 and an initial load adjusting mechanism 57.
Supported by. The front end 31b includes a support plate 47b and a fixing bolt 47 on the front spring bracket 47a.
It is fastened and fixed at c. Rubber sheets 47e are respectively inserted between the front end portion 31b and the bracket 47a and the support plate 47c. This sheet 4
7e is for alleviating the stress when the resin is sandwiched by the metal.

The initial load adjusting mechanism 57 has the following structure. Left and right branch portions 6a of the down tube 6
The left and right guide brackets 58 are fixed to each other, the supporting bolts 59 are bridged and inserted between the vertically extending elongated holes 58a of the brackets 58, and fixed by nuts 59a. A connecting hole 60a formed at the lower end of the adjusting bolt 60 is fitted and connected to the central portion of the support bolt 59, and the adjusting bolt 60 is
The threaded portion 60b of the support bracket 61 is inserted into the lower connection portion 61c of the support bracket 61, and the threaded portion 60b is fitted with the adjusting nut 60c.
It has a screwed structure.

The connecting portion 47d of the front spring bracket 47 is attached to the support bolt 59 and the adjusting bolt 60 is attached.
It is rotatably connected via a collar 59b that restricts lateral movement and a bearing 59c. As a result, the front spring bracket 47a, and thus the front end portion 31 of the leaf spring 31 are
b is pivotally supported in the front-back direction with respect to the vehicle body frame 2 and its vertical position is adjustable.

Next, the function and effect of this embodiment will be described. In the device of this embodiment, when the rear wheel 26 rides on, for example, a convex portion of the road surface, the rear arm 21 is lifted by the impact force, and the rear end portion 31a of the leaf spring 31 is accordingly moved to the intermediate link 38,
The leaf spring 31 is pulled up via the spring link 39, and the leaf spring 31 bends around the front pillow 62 as a fulcrum to alleviate the impact force. When the rear arm 31 further rises, the leaf spring 31 is further bent around the rear pillow 63 as a fulcrum, the spring characteristic is further raised, and the impact force is further alleviated (see the chain double-dashed line in FIG. 1).

The piston 33 in the damper 30 rotates as the rear arm 21 moves up and down, and the working oil in one chamber flows into the other chamber through the throttle mechanism of the oil passage to reduce the damping force. Occurs, and the irregular vertical vibration of the rear wheel 26 is suppressed.

The initial load of the leaf spring 31 can be adjusted by loosening the nut 59a and rotating the adjusting nut 60c of the initial load adjusting mechanism 57. For example, if the adjustment nut 60c is rotated clockwise, the adjustment bolt 60
Rises, the front end 31b of the leaf spring 31 is pulled up,
The leaf spring 31 bends around the front pillow 62 as a fulcrum, the initial load increases, and the leaf spring 31 has a stiffer spring characteristic. In this case, the vehicle height on the rear wheel 26 side becomes high.

When the leaf spring 31 is bent and deformed by the rise of the rear arm 21, the angle of the front end portion 31b of the leaf spring 31 changes (see the chain double-dashed line in FIG. 1). In this case, the front spring bracket 47a swings around the support bolt 59, thereby absorbing the angle change.

As described above, in this embodiment, the initial load of the leaf spring 31 can be adjusted by simply rotating the adjusting nut 60c of the adjusting mechanism 57, which facilitates the adjusting work. Further, this adjusting mechanism 57 can be easily operated from between the front wheels, and the adjustment work is easy from this point as well.

The front end portion 3 due to the bending deformation of the leaf spring 31
The change in angle of 1b can be easily absorbed because the front spring bracket 47a is rotatable around the support bolt 59. Therefore, it is possible to prevent an unfavorable bending force or a pulling force from acting on the front end portion 31b of the leaf spring 31 and prevent an unreasonable load from acting on the leaf spring 31, so that the durability of the leaf spring 31 can be improved.

8 to 10 are views showing a second embodiment of the present invention, which is an example in which the initial load adjusting mechanism is arranged at the rear end portion of the leaf spring. In the figure, the same reference numerals as those in FIGS. 1 to 7 indicate the same or corresponding parts.

In the second embodiment, the rotary shaft 6 of the damper 30 is
7 is arranged coaxially with the pivot shaft 27 of the rear arm 21, and the upper and lower boss portions 32d and 32e of the damper case 32 are arranged.
Is a boss portion 36a formed integrally with the crankcase 13,
It is bolted and fixed to 13b. In addition, the rotary shaft 6
A rear end portion 67a of the damper arm 67b fixed to 7 is bolted to a support bracket 24b fixed to the cross pipe 24.

The front end portion 31b of the leaf spring 31 is pivotally supported by a support boss portion 13c formed on the bottom surface of the crankcase 13 via a pivot support mechanism 47 including a front spring bracket 47a and a support bolt 49a. ..

A fulcrum plate 50 serving as a fulcrum at the time of bending is arranged at the center of the leaf spring 31, and the boss portion 50a of the fulcrum plate 50 is a support boss portion 28a formed integrally with the oil pan 28. It is pivotally supported by a support pin 52. A block 62 made of an elastic material such as rubber is in contact with the upper surface of the fulcrum plate 50, and the block 62 is arranged and fixed in a holding recess 28c of the oil pan 28. The block 62 is for absorbing vibration due to small unevenness on the road surface.

The rear end portion 31a of the leaf spring 31 is pressed onto the support portion 43b of the rear spring bracket 43 by a pressing plate 43c.
And a fixing bolt 45. A link mechanism 67 is arranged between the rear spring bracket 43 and the cross pipe 24. The link mechanism 67 is
Connect the upper and lower brackets 64 and 66 with the adjusting bolt 65, and then use the right and left screw upper and lower lock nuts 65a and 65
It has a structure locked by b and also functions as an initial load adjusting mechanism.

The upper bracket 64 of the link mechanism 67 is axially supported by a support bracket 24a fixed to the lower surface of the cross pipe 24 with support bolts 41a and nuts 41b. The lower bracket 66 is made of rubber bush 42.
It is pivotally supported by the connecting portion 43a of the rear spring bracket 43 via. The rubber bush 42 has a rubber body 4 between the outer pipe 42a and the inner pipe 42b.
2c is baked and fitted.

In the second embodiment, the initial load of the leaf spring 31 can be adjusted simply by loosening the lock nuts 65a and 65b and rotating the adjustment bolt 65, which facilitates the adjustment work.

The rear end portion 31a due to the bending of the leaf spring 31
The change in the angle is absorbed by the link mechanism 67 swinging around the support bolt 44a, and it is possible to prevent an unreasonable load from acting on the leaf spring 31.

[0043]

As described above, according to the rear wheel suspension system for a motorcycle according to the present invention, the distance between the front end or the rear end of the leaf spring and the vehicle body fixing part or the rear arm can be adjusted. Since the load can be adjusted by simple operation and the leaf spring is supported via the pivotal support mechanism and the link mechanism, it is possible to prevent the leaf spring from being subjected to an unreasonable load and improve the durability of the leaf spring. is there.

[Brief description of drawings]

FIG. 1 is a side view of a rear wheel suspension system for a motorcycle according to a first embodiment of the present invention.

FIG. 2 is a plan view of the device of the first embodiment.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a side view of the initial load adjusting mechanism portion of the first embodiment.

FIG. 6 is a sectional front view of the initial load adjusting mechanism portion.

FIG. 7 is a left side view of a motorcycle equipped with the device of the first embodiment.

FIG. 8 is a side view of a rear wheel suspension system for a motorcycle according to a second embodiment of the present invention.

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

10 is a sectional view taken along line XX of FIG.

[Explanation of symbols]

 1 Motorcycle 6 Down Tube (Vehicle Frame) 12 Engine 21 Rear Arm 26 Rear Wheel 29 Rear Wheel Suspension 30 Damper 31 Leaf Spring 31a Front End 31b Rear End 47 Pivot Mechanism 57 Initial Load Adjustment Mechanism 62, 63 Front, Rear Pillow (fulcrum) 67 Link mechanism

Claims (1)

[Claims] 1. A rear arm, a body frame or an engine (hereinafter, referred to as a vehicle body fixing portion), which includes a buffer spring for reducing a shock applied to a rear wheel from a road surface, and a damper for suppressing an irregular vertical vibration of the rear wheel. In a suspension system for a rear wheel of a motorcycle interposed between the vehicle body and the vehicle body fixing portion, the buffer spring is arranged below the engine as a strip plate-shaped plate spring, and a front end portion of the plate spring is connected via a pivot mechanism. And the rear end is supported by the rear arm via a link mechanism, and a fulcrum for bending the leaf spring as the rear arm rises is disposed substantially in the center in the length direction of the leaf spring. A rear wheel suspension system for a motorcycle, wherein at least one of a pivot mechanism and a link mechanism is provided with an initial load adjusting mechanism capable of adjusting a distance between the leaf spring and a vehicle body fixing portion or a rear arm.