JPH05178263A - Damper arrangement structure for rear wheel suspension for motorcycle - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a damper arrangement structure for a rear wheel suspension system for a motorcycle, which can improve space efficiency and sufficiently secure the rigidity of a rear arm. [Composition] A rear wheel for a motorcycle, which is provided between a rear arm and a vehicle body fixing portion, and which is provided with a buffer spring for cushioning a shock applied to a rear wheel from a road surface and a damper for suppressing an irregular vertical vibration of the rear wheel. The arrangement structure of the dampers of the suspension device 29 is configured. In this case, the buffer spring is replaced by a plate-shaped plate spring 3
It is placed below the engine as 1. In addition, the damper
A damper case 32 having a substantially box shape and having a rotary shaft 34 inserted at one end, and a plate shape having one end fixed to the rotary shaft 34 and housed and arranged in the damper case 32 to define two chambers in the case. And a wing-shaped piston 33. The damper 30 is arranged such that the rotary shaft 34 faces the vehicle width direction and the damper case 32 is vertically long, and the rotary shaft 34 is connected to the rear arm 21 while the damper case 32 is connected to the vehicle body frame. Fixed to.

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 arrangement structure of the damper when a rotary type is used as the damper.

[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 generally arranged between the portion near the pivot portion of the rear arm and the lower portion of the fuel tank of the vehicle body frame or the lower portion of the seat directly or through a link mechanism (for example, Japanese Patent Laid-Open No. 59-59). -120585).

However, in the above-mentioned conventional apparatus, 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 that the space efficiency is poor in the arrangement of parts, such as the fact that it cannot be formed in a straight line.

[0004]

On the other hand, the present inventors are currently studying to adopt a leaf spring in place of the coil spring and a rotary damper in place of the telescopic damper. .. When the suspension system including the leaf spring and the rotary damper is adopted, the space efficiency can be improved, but the shape of the rear arm is restricted depending on the structure of the rotary damper itself and the arrangement structure thereof. In particular, there is a concern that the cross-sectional area of the cross member that connects the left and right arm bodies cannot be sufficiently secured, and the rigidity of the rear arm decreases.

The present invention has been made in view of the problems of the above-mentioned conventional structure and the problems when the rotary damper is adopted. The motorcycle can improve space efficiency and sufficiently secure the rigidity of the rear arm. It is an object of the present invention to provide a damper arrangement structure for a rear wheel suspension system for use.

[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 arrangement structure of the damper of the rear wheel suspension system for a motorcycle interposed in the above, the buffer spring is arranged below the engine as a strip plate-shaped plate spring, and the damper is substantially box-shaped and has a rotary shaft at one end. A rotary damper comprising a damper case inserted through and a plate-shaped wing-shaped piston, one end of which is fixed to the rotary shaft and is housed in the damper case and defines two chambers in the case, Damper
The rotary shaft is oriented in the vehicle width direction, and the damper case is arranged to be vertically long. The rotary shaft is connected to the rear arm, while the damper case is fixed to a vehicle body frame or an engine.

[0007]

According to the damper arranging structure of the rear wheel suspension system according to the present invention, the damper case has a shape in which the rotary shaft is inserted through one end of the box body. Therefore, the damper case extends in one direction from the rotary shaft. Is playing. Since the tamper case is arranged vertically, the space required for arranging the damper case in the cross member direction is small, and therefore, the cross sectional area of the cross member can be sufficiently secured, which is advantageous in securing the rigidity of the rear arm.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 are views for explaining a damper arrangement structure of a rear wheel suspension system for a motorcycle according to a first embodiment of the present invention, FIG. 1 is a side view, FIG. 2 is a plan view, and FIG. One
III-III sectional view, FIG. 4 is a left side view of a motorcycle equipped with the device.

In the figure, 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 brackets 5 are connected to the rear ends of the rear half portion 4b branched to the left and right of the tank rail 4. Further, the rear ends of the left and right branch portions 6a of the down tube 6 are connected to the lower ends of the rear arm brackets 5 and 5 and the down tube 6 is
The front half portion 6b consisting of one square pipe is connected to the head pipe 3. Further, 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 has a structure in which the front half portions 4a of two square pipes are overlapped with each other in the vehicle width direction and welded together, and the rear half portion 4b is separated left and right. The left and right rear arm brackets 5 and 5 are connected by an upper cross pipe 5b and a lower cross pipe 5c. Reference numeral 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 in a forwardly inclined state on a front portion of a crankcase 13 integrated with a transmission case. It has a structure. This engine 12 has the above crankcase 13
The front and bottom bosses 13a and 13b of the down tube 6
Of the left and right branch portions 6a are bolted and fixed to the support bracket 61 fixed to the rising portions of the left and right branch portions 6a, and the bracket 6c welded and fixed to the bottom portion of the crankcase 13.
The rear boss portion 13c is supported by a pivot shaft 27 described later,
Further, the suspension boss portion 15a of the cylinder head 15 is mounted on the vehicle body frame 2 by bolting and fixing it to the tank rail 4 via the suspension bracket 15b.

A rear arm 21 is pivotally supported by the rear arm bracket 5 so as to be vertically swingable. The rear arm 21 includes a pair of left and right rectangular tube-shaped arm bodies 22.
A pivot portion 23 is formed at the front end of each of a and 22b, and the rear portions of the pivot portions 23 of the arm bodies 22a and 22b are connected and fixed by a square tubular cross member 24. A rear wheel 26 is pivotally supported by an axle 25 that is inserted and fixed between the rear ends of the 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 provided 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 movement 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 5 that connects the leaf spring 31 and the damper 30 to the rear arm 21.
6 and 6.

The leaf spring 31 is made of resin in the form of a strip plate extending in the vehicle front-rear direction below the crankcase 13, and is gradually thinned from the central portion toward the front and rear end portions.

The front end portion 31b of the leaf spring 31 is fixed to the support portion 47a of the front spring bracket 47 by a support plate 48a and a fixing bolt 48b, and the front spring bracket 47 is connected via an initial load adjusting mechanism 57. It is supported by the bracket 61. In addition, the rear end portion 3 of the leaf spring 31
1a is supported by the rear arm 21 via the link mechanism 56.

The leaf spring 31 is provided above the leaf spring 31 substantially in the longitudinal center thereof as the rear arm 21 moves up and down.
The front and rear pillows 62 and 63 for deforming are arranged so that their front and rear positions can be adjusted. Front pillow 6 above
Reference numeral 2 denotes a pair of left and right side plates 62a, each having a plurality of mounting screw holes 62c formed in a row in the front-rear direction, connected by a base plate 62b, and a relatively hard rubber on the lower surface of the base plate 62b. A block 62d made of an elastic material such as urethane foam is attached, and the side plate 62a is fastened and fixed to the left and right branch portions 6a of the down tube 6 with bolts 62e. Further, the rear pillow 63 is
On the lower surface of the base plate 63a, the block 6 made of the elastic body is formed.
The base plate 63a is fixed to the bottom plate 63d welded and fixed to the branch portion 6a and the lower cross pipe 5c with bolts 63c.

The link mechanism 56 includes a pair of left and right spring links 3 connected to the rear end portion 31a of the leaf spring 31.
9, 39, a pair of left and right damper arms 37, 37 for rotating a piston of a damper, which will be described later, the damper arm 37, and the spring link 39, and the rear arm 21.
It is composed of a pair of left and right intermediate links 38 that connect and.

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 connection 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.

Further, connecting pins 38h are provided on the outer surface of each of the intermediate links 38, 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 shown in b.
Is inserted through a bearing, and the rear end portion 31a of the leaf spring 31 is bolted and fixed to the support portion 43b of the rear spring bracket 43. As a result, the leaf spring 31
The rear end portion 31a is supported by the rear arm 21 via a spring link 39 and an intermediate link 38.

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 a box-shaped body in a side view that is substantially fan-shaped and includes a and a lid 32b. The rotary shaft 34 is inserted into the lower end portion 33a and spline-fitted, and the rotary shaft 34 is attached to the damper case 32.
The structure is rotatably supported by. 32f
Is a support bracket for supporting the bump stopper 54 made of an elastic body, and 24c is a stopper member.

The damper 30 has the rotating shaft 34.
Is oriented rearward of the pivot shaft 27 in the vehicle width direction, and the damper case 32 is arranged so as to stand upright with the rotation shaft 34 at the lower end, that is, to be vertically long. The upper and lower boss portions 3 formed integrally with the damper case 32
2d and 32e are fixed to the support brackets 36a and 36b with fixing bolts 35a and 35b. The support brackets 36a and 36b are welded and fixed to the upper cross pipe 5b and the lower cross pipe 5c, respectively.

The upper end 37d of the damper arm 37 is spline-fitted to both ends of the rotary shaft 34, which project outward from the damper case 32, and is fixed by tightening a nut. Although not shown, the lid 32b has an oil passage formed therein for communicating the two chambers defined by the piston valve 33, and a throttle mechanism is arranged in the passage. When the piston valve 33 is rotated around the rotation shaft 34, the hydraulic oil moves from one chamber of the damper case 32 to the other chamber through the throttle mechanism, and thereby a damping force is generated.

Next, the function and effect of this embodiment will be described. In the device of the present embodiment, 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, and the rear end portion 31a of the leaf spring 31 passes through the intermediate link 38 and the spring link 39 accordingly. The leaf spring 31 is bent by using the front pillow 62 as a fulcrum, and the spring force at this time relaxes the impact force. Then, when the rear arm 21 further rises, the leaf spring 31 also comes into contact with the rear pillow 63 and bends with this portion as a fulcrum.
Impact force is alleviated. Note that the raised position of the rear arm 21 is restricted by the bump stopper 54.

Further, as the rear arm 21 is raised and lowered, the damper arm 37 is vertically swung via the intermediate link 38, whereby the piston 33 is rotated around the rotary shaft 34 in the front-rear direction, and one of the chambers in one of the chambers is rotated. The hydraulic oil passes through the throttle mechanism and flows into the other chamber, so that a damping force is generated and irregular vertical vibration of the rear wheel 26 is suppressed.

In the rear wheel suspension device 29 performing such an operation, the damper case 32 is fan-shaped with the rotating shaft 34 as the center, and the rotating shaft 34 is positioned at the lower end and erected upward. The space required for disposing the damper case 32 in the direction of the cross member 24 is small. Therefore, a sufficient cross-sectional area of the cross member 24 can be secured,
The rigidity of the rear arm 21 can be sufficiently ensured.

In mounting the damper 30, the relatively lightweight piston 33 is connected to the rear arm 21 and the relatively heavy damper case 32 is fixedly supported by the rear arm bracket 5, so that the portion of the portion that swings together with the rear arm 21 is fixed. Weight, that is, unsprung weight, can be reduced.

Further, compared with the case where the coil spring and the cylindrical damper described above are adopted, there are fewer obstacles on the intake path of the engine, the path can be linearized, and the intake resistance can be reduced. Easy to put on and take off.

Although the damper 30 is arranged upward in the first embodiment, the direction of the damper is not limited to upward. FIG. 5 is a view showing a second embodiment in which the damper is arranged downward, and in the figure, the same reference numerals as those in FIGS. 1 to 4 indicate the same or corresponding parts.

The rotary damper 30 is arranged downward with the rotary shaft 34 located at the upper end, and its upper and lower boss portions 32d and 32e are bolted to the upper piece 36a and the lower piece 36b of the support bracket 36. The support bracket 36 is fixed to the engine suspension pipe 5d and the lower cross pipe 5c by welding. Further, in this embodiment, the bump stopper 54 is integrally formed on the lower surface of the damper case 32, and the support bracket 3 is integrally formed.
It is supported by 2f. A heat insulating film 46 is formed on the side surface and the upper surface of the leaf spring 31. This is for cutting off heat from the exhaust pipes 18a, 18b passing laterally.

In the second embodiment, only one damper arm 37 for driving the piston 33 of the damper 30 is arranged on the right side, and the damper arm 37 is connected to the intermediate link 38 together with the upper end of the spring arm 39. They are connected by a connecting bolt 40a. The intermediate link 38 is connected to the support bracket 24a with a connecting bolt 41b.

The lower end of the spring arm 39 is connected to the rear spring bracket 43 via a rubber bush 43a, and the rear end 31a of the leaf spring 31 is connected to the support plate 43b of the spring bracket 43 by a pressing plate 43c ,. It is fixed with a fixing bolt 45. The front end portion 31b of the leaf spring 31
Is fixed to a support portion 47b of the front spring bracket 47 with a support plate 48a and a fixing bolt 48b. The connecting portion 47a of the front spring bracket 47 is a support pin 49a.
Is pivotally supported by the support boss portion 13c of the crankcase 13.

An adjusting plate 50 capable of adjusting an initial load is arranged above the central portion of the leaf spring 31.
The plate 50 is a plate-shaped body having a rubber sheet 51 attached to an arc-shaped pressing surface.
a is pivotally supported by a support boss portion 28a formed in the oil pan 28 via a support pin 52. An adjusting bolt 53 is screwed into the adjusting plate 50, and the head of the bolt is adjusted by the adjusting seat surface 2 formed on the oil pan 28.
It is in contact with 8b. Incidentally, 53a is a lock nut.

In the second embodiment, when the damper 30 is arranged, the head of the damper case 32 is located between the pivot portion 23 and the cross pipe 24, and the damper case 32 is arranged downward. It is possible to avoid the interference between the cross pipe 24 and the damper case 23 due to the vertical swing of 21. Therefore, the cross sectional area of the cross member 24 can be set large, and the rigidity of the rear arm 21 can be improved accordingly.

Further, in the second embodiment, since the damper 30 having a relatively large weight is arranged downward, the center of gravity can be lowered by that much. Furthermore, since the rotary shaft 34 is offset from the pivot shaft 27 to the rear wheel 26 side,
The swing angle θ2 of the damper arm 37 and the swing angle of the airfoil piston 33 are larger than the swing angle θ1 of the rear arm 21, and the degree of freedom in setting the damper characteristics can be expanded.

Although the rotary shaft 34 of the damper 30 is offset behind the pivot shaft 27 in the first and second embodiments, the position of the rotary shaft is not limited to the offset. FIG. 6 is a view showing a third embodiment in which the rotary shaft is coaxial with the pivot shaft, and the same reference numerals as those in FIGS. 1 to 5 show the same or corresponding portions in the drawing.

In the third embodiment, the rotary shaft 6 of the damper 30 is used.
7 is formed in a tubular shape and is arranged so as to surround the pivot shaft 27. The rear end portion 67a of the damper arm 67b fixed to the rotating shaft 67 is bolted to a fixed flange 24b fixed to the cross member 24. Also, the upper and lower boss portions 32d of the damper case 32,
32e is bolted and fixed to upper and lower support boss portions 36a and 13b integrally formed with the crankcase 13. As a result, the piston 33 of this embodiment is rotated by the same angle as the rear arm 21.

The rear end portion 31a of the leaf spring 31 is connected to the support bracket 24a of the cross member 24 via the rear spring bracket 43 and the initial load adjusting mechanism 63. The adjusting mechanism 63 includes upper and lower brackets 64,
It has a structure in which 66 is connected by an adjusting bolt 65. Note that reference numerals 65a and 65b are lock nuts having right-hand and left-hand threads.

At the center of the leaf spring 31, a support plate 50 serving as a fulcrum when the leaf spring 31 is bent is vertically swingably arranged. The plate 50 is a plate-shaped body having an arcuate pressing surface, and an elastic block 62 housed and fixed in the supporting recess 28c of the oil pan 28 is in contact with the upper surface of the plate 50.

In the third embodiment, since the rotary shaft 67 is arranged coaxially with the pivot shaft 27 and the damper case 32 is arranged downward, the damper 30 can be brought closer to the engine side and the cross member. A sufficient cross-sectional area of 24 can be secured and so-called mass concentration can be achieved.

As described above, according to the damper arranging structure of the rear wheel suspension system for a motorcycle according to the present invention, the damper is a rotary type in which the rotating shaft is offset to one end of the damper case. Since the damper case is arranged vertically,
The arrangement space required in the direction of the cross member of the damper is small, and therefore, the cross-sectional area of the cross member can be increased accordingly, and the rigidity of the rear arm can be sufficiently secured.

[Brief description of drawings]

FIG. 1 is a side view showing a damper arrangement structure 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 first embodiment.

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

FIG. 4 is a left side view of a motorcycle that employs the device of the first embodiment.

FIG. 5 is a side view showing a bumper arrangement structure according to a second embodiment of the present invention.

FIG. 6 is a side view showing a damper arrangement structure according to a third embodiment of the present invention.

[Explanation of symbols]

 1 Motorcycle 12 Engine 21 Rear Arm 26 Rear Wheel 29 Rear Wheel Suspension 30 Damper 31 Leaf Spring 32 Damper Case 33 Airfoil Piston 34, 67 Rotating Shaft

Claims (1)

[Claims] 1. A motorcycle 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, the motorcycle being interposed between a rear arm and a vehicle body fixing portion. In the arrangement structure of the damper of the rear wheel suspension device, the buffer spring is arranged below the engine as a strip plate-shaped plate spring, and the damper case is a substantially box-shaped damper case having a rotary shaft inserted at one end thereof, A rotary damper, one end of which is fixed to a rotary shaft, is housed and arranged in the damper case, and includes a plate-shaped wing-shaped piston that defines two chambers in the case, and the damper has the rotary shaft. A motorcycle characterized by being oriented in the width direction and arranged so that the damper case is vertically long, connecting the rotary shaft to the rear arm, and fixing the damper case to a vehicle body frame or an engine. Rear wheel suspension damper arrangement.