JPH06298149A - Rear arm for motorcycle - Google Patents

Abstract

PURPOSE:To prevent vibration and noise by pivotally fitting front end head parts to a body frame, and providing vibrationproof members in right and left a pair of arm parts extending rearward or a cross member mounted between the arm parts. CONSTITUTION:Front end heads 2 are pivotally fitted to a body frame rotationally movably, and right and left a pair of arm parts 3 are rearward extendingly provided, so as to constitute a rear arm 1. Vibrationproof members 6-8 consisting of rubber dampers are internally mounted in the respective arm parts. A cross member 4 is provided between the arm parts 3, and the vibrationproof member can be mounted therein. These vibrationproof members 6 8 are constituted for example so that each one is formed into a square pillar shape and provided with large and small each two lightening holes. By this constitution, vibration propagated to the rear arm 1 is absorbed in the vibrationproof members 6-8. Further, by the vibrationproof members 6-8, rigidity of the rear arm 1 is improved so as to raise the natural frequency, and hence resonance is restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear arm of a motorcycle.

[0002]

2. Description of the Related Art Generally, in a motorcycle, a rear wheel is rotatably supported by a rear end portion of a rear arm that swings up and down, and the front end head portion of the rear arm is pivoted on a body frame by a pivot shaft. A rear wheel is rotatably supported at the rear ends of a pair of left and right arms that are pivotally mounted freely and extend rearward from the front head.

[0003]

By the way, engine vibration inevitably propagates to the rear arm, but particularly when the natural frequency of the rear arm matches the frequency of the engine, the rear arm resonates and generates noise. is there.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a rear arm for a motorcycle capable of suppressing the generation of vibration and noise.

[0005]

In order to achieve the above object, the present invention provides a pair of left and right arms in which a front end head portion is pivotally attached to a vehicle body frame and extends rearward from the front end head portion. In a rear arm for a motorcycle in which a rear wheel is rotatably supported at a rear end portion of the arm portion, a vibration isolating member is provided on each of the arm portions or a cross member bridged between the both arm portions. .

[0006]

According to the present invention, the engine vibration propagated to the rear arm is effectively absorbed by the vibration isolating member provided on the rear arm, so that the vibration and noise of the rear arm are suppressed.

Further, since the rigidity of the entire rear arm is increased by the vibration isolating member, the natural frequency of the rear arm is increased and resonance is suppressed, which also suppresses vibration and noise of the rear arm.

If an elastic body having a high sound absorbing effect is used as the vibration isolating member, the sound insulating effect of the rear arm can be further enhanced.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. <First Embodiment> FIG. 1 is a side view of a rear arm for a motorcycle according to a first embodiment of the present invention, FIG. 2 is a plan view of the rear arm, and FIG. 3 is an enlarged sectional view taken along line AA of FIG. .

In the rear arm 1 for a motorcycle shown in FIGS. 1 and 2, reference numeral 2 denotes a pair of left and right head pipes which form a front end head portion, and each head pipe 2 is integrally formed by casting, and a front portion thereof is formed. Is the vehicle width direction (vertical direction in Fig. 2)
A pipe portion 2a penetrating to is integrally formed.

At the rear end of each head pipe 2,
A front end portion of an arm portion 3 having a rectangular pipe-shaped cross section (see FIG. 3) extending rearward of the vehicle body (rightward in FIG. 1) is inserted and welded. A cross member 4 is installed between the front end portions of the pair of left and right arm portions 3, and an end piece 5 which is an extrusion molded product is provided at the rear end portion of each arm portion 3.
Is inserted and welded.

By the way, in the rear arm 1 according to this embodiment, a vibration-proof member 2 is provided at the front end of each arm 3.
The rubber dampers 6 and 7 are continuously inserted,
One damper 8 is inserted behind them.
For example, the damper 6 is formed in a prismatic shape, and as shown in FIG. 3, the damper 6 is formed with four lightening holes 6a and 6b of two large and small holes in total. The other dampers 7 and 8 are also constructed in the same manner as the damper 6.

The front end of the rear arm 1 is rotatably attached to a body frame (not shown) by a pivot shaft (not shown) which is inserted through the pipe portions 2a of the pair of left and right head pipes 2, and the rear end thereof is pivoted. A rear wheel (not shown) is rotatably supported on the portion by a rear axle (not shown) which is horizontally inserted through the pair of left and right end pieces 5. Therefore, the rear arm 1
Is swingable up and down together with the rear wheel about a pivot shaft, which is suspended on the vehicle body side via a rear suspension (not shown).

In a motorcycle, engine vibration inevitably propagates to the rear arm 1 via the vehicle body frame. In this embodiment, however, the dampers 6, 7, 8 are provided in the respective arm portions 3 of the rear arm 1. Since it is inserted, the engine vibration propagating to the rear arm 1 is dampened by the dampers 6, 7, 8
It is effectively absorbed by the vibration absorbing effect of. Further, the rigidity of the rear arm 1 is increased by the dampers 6, 7, 8 and the natural frequency thereof is also increased, so that resonance due to engine vibration is suppressed.

Therefore, the vibration of the rear arm 1 is suppressed to a small level, and the generation of noise due to the vibration can be effectively prevented. <Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. Incidentally, FIG. 4 is a broken side view of the arm portion of the rear arm according to the second embodiment, and FIG. 5 is a plan view of the same.

In this embodiment, a rubber prismatic damper 9 is press-fitted into each arm portion 3 of the rear arm 1 as a vibration isolating member.

That is, a rectangular cutout piece 3a is formed on the upper and lower surfaces of each arm portion 3 by being bent inwardly of the arm portion 3, and an upper and lower surface of the damper 9 is engaged with the cutout piece 3a. A concave groove 9a to be fitted is formed.

Before the arm portion 3 is welded to the head pipe (not shown), the damper 9 is press-fitted into the arm portion 3 through the front end opening portion of the arm portion 3 and formed on the upper and lower surfaces thereof. The positioning is performed by engaging the cutout piece 3a of the arm portion 3 with the groove 9a.

Therefore, also in this embodiment, the vibration and noise of the rear arm 1 are effectively suppressed by the vibration absorbing effect of the damper 9 as in the first embodiment.

Here, various aspects of the positioning method of the damper 9 are shown in FIGS. 6 to 9, respectively.

FIG. 6 is a cutaway side view of the arm portion 3 of the rear arm 1. As shown in FIG. 6, a part of the upper and lower surfaces of the arm portion 3 is deformed into a concave shape so that the portion is inwardly directed to the arm portion 3. The damper 9 may be positioned by providing protrusions 3b projecting toward each other and engaging these protrusions 3b with the recessed grooves 9b formed in the upper and lower surfaces of the damper 9.

FIG. 7 is a plan sectional view of the arm portion 3 of the rear arm 1. In the example shown in this figure, the inner surface of the damper 9 is provided so as to project toward the inside of the vehicle body (upward in FIG. 7). Protrusion 9
The damper 9 is positioned by engaging c with the hole 3c formed in the inner wall of the arm portion 3. still,
A concave groove 9d is formed on the inner surface of the damper 9 to allow the deformation of the protrusion 9c when the damper 9 is press-fitted into the arm portion 3.
Are formed.

Further, FIG. 8 is a plan sectional view of the arm portion 3 of the rear arm 1. In the example shown in this figure, after the damper 9 is press-fitted into the arm portion 3 at a predetermined position, it is attached to the inner wall of the arm portion 3. The blind rivet 10 is inserted through the bored hole 3d, the tip of the blind rivet 10 is engaged with the recess 9e of the damper 9, and the blind rivet 10 is deformed as shown in the drawing to position the damper 9. Although not shown, the damper 9 may be positioned by screwing it with a bolt or the like that is screwed onto the arm 3.

As shown in the plan sectional view of FIG. 9, an opening 3e is formed inside the arm portion 3 of the rear arm 1 (inside the vehicle body), and the damper 9 is inserted into the arm portion 3 through the opening 3e. After that, the screw 11 is tightened and the plate-like lid member 12
The damper 9 may be positioned at a predetermined position in the arm portion 3 by covering the opening 3e with. <Third Embodiment> Next, as a third embodiment of the present invention, various modes of a method of inserting and fixing a vibration-proof member into an arm portion will be described with reference to FIG.
It will be described with reference to FIG.

In the method shown in FIGS. 10 to 12,
As shown in FIG. 10, a vibration damping member 1 formed by baking a rubber damper 14 on a leaf spring 13 that opens in a free state.
Prepare 5. Then, as shown in FIG. 11, the anti-vibration member 15 is moved in a state where the open end of the leaf spring 13 of the anti-vibration member 15 is sandwiched by a tool 16 such as pliers to narrow the width of the anti-vibration member 15.
As shown in FIG. 3, the rear arm 1 is inserted into the arm portion 3 through a hole 3f opened on the lower surface of the arm portion 3, and then the tool 16
When released, the leaf spring 13 of the vibration isolating member 15 tries to return to the original free state, so that the left and right dampers 14 are pressed against the inner side wall of the arm portion 3 and come into close contact with each other, as shown in FIG.
The anti-vibration member 15 is inserted and fixed at a predetermined position in each arm portion 3.

As shown in FIG. 13, the open end of the leaf spring 13 of the vibration isolating member 15 is closed by a mounting clip 17, and after the vibration isolating member 15 is mounted in the arm portion 3 in this state, When the mounting clip 17 is removed, the leaf spring 13 expands due to its elastic force as described above, so that the vibration damping member 1
5 is fixed at a predetermined position in each arm portion 3.

The method shown in FIGS. 14 and 15 is the same as that shown in FIG.
As shown in FIG. 4, a vibration damping member 21 (screw type) is prepared by screwing hexagon socket head bolts 20 into a flexible leaf spring 19 formed by baking rubber dampers 18 left and right. The anti-vibration member 21 is inserted into the arm portion 3 through the hole 3g (see FIG. 15) opened on the lower surface of the arm portion 3 of the rear arm 1 in a state where the width thereof is narrowed, and then the hexagon socket head cap bolt 20
If you use a hexagon wrench (not shown) to turn the
Since the leaf spring 19 of the vibration isolating member 21 spreads in the arm portion 3, the damper 18 burned on the leaf spring 19 is pressed against the inner side wall of the arm portion 3 and is brought into close contact therewith, so that the vibration isolating member 21 is attached to each arm portion 3 It is inserted and fixed at a predetermined position inside and used for absorbing engine vibration.

Further, in the method shown in FIG. 16, the central curved portion is made of rubber above and below one surface of the leaf spring 22 which can be deformed in a diaphragm manner to any state shown by the chain line and the solid line in FIG. A vibration-damping member 25 (diaphragm type) is prepared by baking the damper 23 of FIG. 2 and baking the same rubber damper 24 on the center portion of the other surface. And
After the leaf spring 22 is deformed as shown by the solid line in FIG. 16 and is inserted into the arm portion 3 from the rear end side thereof, the vibration isolator 25 is not opened from the hole 3h opened in the side wall of the arm portion 3. When the bar-shaped tool shown in the figure is inserted and the central portion of the leaf spring 22 is pressed by the tip of the tool, the leaf spring 22 is deformed as shown by the chain line in FIG. Since it comes into close contact with the wall, the vibration isolator 25 is fixedly supported by the three dampers 23, 24 in the arm portion 3, and is used for vibration isolation of the rear arm 1. <Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIGS. 17 is a partial side sectional view of the arm portion of the rear arm according to the fourth embodiment, and FIG. 18 is a cutaway plan view of the same.

In this embodiment, a rectangular elongated hole 3i elongated in the vehicle front-rear direction (left and right direction in FIG. 17) is formed on the lower surface of the arm portion 3 of the rear arm 1, and the vibration-proof member 2 is formed from the elongated hole 3i.
6 is inserted into the arm portion 3 and fixed.

The vibration isolating member 26 is a rectangular flat plate-like lid member 27 which is larger than the elongated hole 3i formed in the arm portion 3.
A disk-shaped plate member 28 having a diameter smaller than the short side length of the same long hole 3i is adhered to the inner side of the cover member 27 and the plate member 2
8, rubber damper 29, bolt 30 and nut 31
It is configured by tightening and integrating.

By the way, the damper 29 is formed in a prismatic shape having a high height, a long side having a length of about the inner width of the arm portion 3 and a short side having a shorter length, which is U. It is held by a character-shaped support fitting 32, and the support fitting 3
The nut 31 is welded to the top of No.2.

Thus, when mounting the anti-vibration member 26 in the arm portion 3, the damper 29 is made long in the front-rear direction of the vehicle body (left-right direction in FIG. 18) as shown by the chain line in FIG. The damper 29 is attached to the long hole 3i of the arm 3.
From the above, it is inserted into the arm portion 3, and then the entire vibration isolator 26 is rotated by an angle of 90 ° in the arrow direction of FIG. Then, as shown by the solid line in FIG. 18, the damper 29 has its end face on the short side closely attached to the inner wall of the arm portion 3, and
The lid member 27 closes the long hole 3i formed in the arm portion 3. Then, when the bolt 30 is tightened thereafter, the damper 29 is compressed and deformed to bulge in the long side direction, and the damper 29 is tightly fitted in the arm portion 3, whereby the vibration-proof member 26 is moved to the arm portion 3. It is fixed in place inside. <Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIG. Note that FIG. 19 is a partial plan sectional view of the arm portion of the rear arm according to the fifth embodiment.

In this embodiment, the arm portion 3 of the rear arm 1
The dynamic damper 33 is incorporated into the arm portion 3 through the opening 3j formed in the inner wall of the plate, which is a lid member.
A weight 36 is supported via a rubber damper 35, and the damper 35 is baked on the plate 34 and the weight 36.

Then, as described above, the dynamic damper 33 is inserted into the arm portion 3 through the opening portion 3j that opens in the arm portion 3, and the plate 34 is screwed into the arm portion 3.
When the dynamic damper 33 is fastened to the inner wall of the rear arm 1, the dynamic damper 33 is mounted at a predetermined position in the arm portion 3, and the vibration and noise of the rear arm 1 are suppressed to a low level by the vibration damping effect of the dynamic damper 33. <Sixth Embodiment> Next, a sixth embodiment of the present invention will be described with reference to FIGS. 20 is a partially cutaway plan view of the arm portion of the rear arm according to the sixth embodiment, and FIG. 21 is a view in the direction of arrow B in FIG.

In the present embodiment, a vibration damping member 40 is formed by integrally baking a cylindrical rubber damper 39 on a substantially disk-shaped lid member 38, and four engaging members are provided on the outer periphery of the lid member 38. Pieces 38a are projected at an equal angle pitch (90 ° pitch), and a handle 38b is fixed to the central portion.

On the other hand, a circular hole 41 is formed in the inner side wall of the arm portion 3 of the rear arm 1, and four engaging members 38a formed on the lid member are to pass around the circular hole 41. The mating grooves 41a are formed at an equal angular pitch (90 ° pitch).

In order to mount the vibration isolating member 40 on the arm portion 3 of the rear arm 1, the engaging piece 38a of the lid member 38 of the vibration isolating member 40 is attached to the arm portion 3 as shown by the chain line in FIG.
The lid member 38 is pushed inward while being aligned with the engaging groove 41a on the side. Then, the damper 39 is compressed and deformed,
The engagement piece 38a of the lid member 38 is engaged with the engagement groove 41 on the arm portion 3 side.
Pass a. Then, while the lid member 38 is being pressed, it is rotated by a predetermined angle (45 °) in the direction of the arrow in FIG. 21, and when the hand is released from the lid member 38, the engaging piece 38a is moved by the restoring force of the damper 39. 3 is pressed against the inner surface of the side wall of the rear arm 3, and thereby the vibration isolator 40 is inserted and fixed at a predetermined position in the arm portion 3 of the rear arm 1 to reduce vibration and noise of the rear arm 1. <Seventh Embodiment> Next, a seventh embodiment of the present invention will be described with reference to FIGS. 22 is a partial side view of the arm portion of the rear arm according to the seventh embodiment, and FIG. 23 is FIG.
2 is a sectional view taken along line CC of FIG.

In this embodiment, as shown in FIG. 23, a part (upper surface and outer surface) of the arm portion 3 of the rear arm 1 is covered with a vibration isolating member 42 having a U-shaped cross section. The vibration member 42 is covered with a protective member 43 made of resin. And
The anti-vibration member 42 and the protection member 43 are connected and integrated with the arm portion 3 by stepped bolts 44 and grommets 45. If an elastic body or the like having a high sound absorbing effect is used as the vibration isolating member 42, the sound insulating effect of the rear arm 1 can be further enhanced.
Further, in the figure, 46 is a brake hose.

By the way, as shown in FIG. 24, a rubber band-shaped elastic member 46 is embedded in the upper surface of the protection member 43 to prevent the rear arm 1 from being struck by a chain (not shown) and vibrating. May be. Incidentally, in FIG. 24, reference numeral 42 is a vibration isolating member. <Eighth Embodiment> In the above-described embodiments, the vibration isolator is incorporated in the arm portion, but in the present embodiment, the vibration isolator is incorporated in the cross member erected on the left and right arm portions.

That is, FIG. 25 is a vertical cross-sectional view of the cross member portion of the rear arm. In this embodiment, the vibration isolator 47 is a prismatic rubber damper, and the vibration isolator 4 is a vibration damper.
7, four lightening holes 47a are formed in the vehicle body front-rear direction (perpendicular to the paper surface of FIG. 25).

By the way, a rectangular opening 4a is formed in the center of the upper wall of the cross member 4 in the vehicle width direction, and the vibration isolator 47 is inserted into the cross member 4 through the opening 4a. The anti-vibration member 47 is pressed and fixed to a bracket 49 which is fastened to the cross member 4 with bolts 48.

Thus, also in this embodiment, the first to the seventh
Similar to the embodiment, the vibration absorbing effect of the vibration isolating member 47 brings about an effect of suppressing the vibration and noise of the rear arm 1 to be low.

[0043]

As is apparent from the above description, according to the present invention, the front end head portion is pivotally attached to the vehicle body frame, and the pair of left and right arms extends rearward from the front end head portion. In a rear arm for a motorcycle in which a rear wheel is rotatably rotatably supported at a rear end portion of the portion, since a vibration damping member is provided on each of the arm portions or a cross member bridged between the both arm portions, Due to the vibration absorbing effect, it is possible to obtain the effect of suppressing the vibration and noise of the rear arm.

[Brief description of drawings]

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

FIG. 2 is a plan view of a rear arm for a motorcycle according to the first embodiment of the present invention.

3 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 4 is a partially cutaway side view of an arm portion of a motorcycle rear arm according to a second embodiment of the present invention.

FIG. 5 is a partial plan view of an arm portion of the motorcycle rear arm according to the first embodiment of the present invention.

FIG. 6 is a partially cutaway side view of an arm portion of a motorcycle rear arm showing a method of positioning a damper.

FIG. 7 is a partial plan cross-sectional view of an arm portion of a motorcycle rear arm showing a method for positioning a damper.

FIG. 8 is a partial plan cross-sectional view of an arm portion of a motorcycle rear arm showing a method for positioning a damper.

FIG. 9 is a partial plan cross-sectional view of an arm portion of a motorcycle rear arm showing a method for positioning a damper.

FIG. 10 is a side view of a vibration isolating member according to a third embodiment of the present invention in a free state.

FIG. 11 is a view showing a state in which the vibration isolating member according to the third embodiment of the present invention is sandwiched by tools.

FIG. 12 is a vertical sectional view of an arm portion of a rear arm for a motorcycle showing a mounted state of a vibration damping member according to a third embodiment of the present invention.

FIG. 13 is a view showing a state in which the vibration isolating member according to the third exemplary embodiment of the present invention is sandwiched by mounting clips.

FIG. 14 is a side view of a vibration isolator (screw opening / closing type) according to a third embodiment of the present invention.

FIG. 15 is a vertical cross-sectional view of an arm portion of a rear arm for a motorcycle showing a mounted state of a vibration damping member (screw opening / closing type) according to a third embodiment of the present invention.

FIG. 16 is a longitudinal sectional view of an arm portion of a rear arm for a motorcycle showing a mounted state of a vibration damping member (diaphragm type) according to a third embodiment of the present invention.

FIG. 17 is a partial side sectional view of an arm portion of a rear arm for a motorcycle according to a fourth embodiment of the present invention.

FIG. 18 is a partially cutaway plan view of an arm portion of a motorcycle rear arm according to a fourth embodiment of the present invention.

FIG. 19 is a partial plan sectional view of an arm portion of a rear arm for a motorcycle according to a fifth embodiment of the present invention.

FIG. 20 is a partially cutaway plan view of an arm portion of a motorcycle rear arm according to a sixth embodiment of the present invention.

21 is a view in the direction of arrow B in FIG.

FIG. 22 is a partial side view of an arm portion of a rear arm for a motorcycle according to a seventh embodiment of the present invention.

23 is a cross-sectional view taken along the line CC of FIG.

FIG. 24 is a view similar to FIG. 23, showing a modification of the seventh embodiment of the present invention.

FIG. 25 is a vertical cross-sectional view of a cross member portion of a motorcycle rear arm according to an eighth embodiment of the present invention.

[Explanation of symbols]

 1 Rear Arm for Motorcycle 2 Head Pipe (Front End Head) 3 Arm 4 Cross Member 6,7,8 Damper (Vibration Isolation Member) 9 Square Column Damper (Vibration Isolation Member) 15 Vibration Isolation Member 21 Vibration Isolation Member 25, 26 Anti-vibration member 33 Dynamic damper (anti-vibration member) 40, 42 Anti-vibration member 47 Damper (anti-vibration member)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Maruyama Yoshihiro, Yamaha Motor Co., Ltd. 2500 Shinkai, Iwata, Shizuoka Prefecture

Claims (1)

[Claims] 1. A front end head portion is rotatably pivotally attached to a vehicle body frame, and a rear wheel is rotatably supported by a rear end portion of a pair of left and right arm portions extending rearward from the front end head portion. A rear arm for a motorcycle as described above, wherein a vibration isolating member is provided on each of the arm portions or a cross member provided between the arm portions.