JP2003072664A - Vehicular rear arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular rear arm capable of preventing fretting without increasing weight. SOLUTION: The vehicular rear frame is attached to a body frame so as to vertically swing and it supports a rear wheel so that the rear wheel can vertically move. The vehicular rear arm has a connecting body swingably attached to the body frame, a pair of right and left arm parts extended rearward with front end parts fixed to the connecting body, and an end member 25 arranged on rear end parts of the arm parts and pierced by a rear wheel shaft rotatably supporting the rear wheel. In the end member 25, a thick part 25d is formed in a range of an inner face part of a rear wheel side making surface contact with other parts, and a planar contact face 25e making surface contact with the other parts is provided on the thick part 25d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle rear arm for connecting a rear wheel to a vehicle body frame in a vertically swingable manner.

[0002]

2. Description of the Related Art Conventionally, in a motorcycle, an engine is supported on a vehicle body frame, a front wheel is arranged on a front head pipe of the vehicle body frame via a front fork, and a rear arm is provided on a rear side of the vehicle body frame. The rear wheel is arranged so as to be swingable in the vertical direction via the. And
The driving force of the engine is transmitted to the rear wheels via the chain.

This rear arm has a right arm portion arranged on the right side of the rear wheel and a left arm portion arranged on the left side of the rear wheel. Front end portions of these right arm portion and left arm portion Is connected to a connecting body located on the front side of the rear wheel, and end members are fixed to the rear end portions of the arm right part and the arm left part.

The front end of the connecting body is rotatably connected to the vehicle body frame, and the rear wheel is rotatably supported by the end member.

The lower end of the rear cushion is connected to the connecting body, and the upper end of the rear cushion is connected to the vehicle body frame.

The right arm portion and the left arm portion are formed in a cylindrical shape by so-called swaging. In the swaging, a mold having a predetermined shape is set in a pipe that is made larger in advance, and a force is applied from the outside to form a predetermined shape along the outer shape of the mold.

[0007]

However, in such a conventional device, the rear wheel shaft is inserted through both end members and screwed into the nuts so that the washer, Bearings, collars, etc. are clamped, and the inner contact surfaces of these end members are in surface contact with the washers, so the contact surfaces are deformed due to engine vibration, etc. Then,
So-called fretting may occur with the washer.

As a countermeasure against this, if the rigidity of the end member is to be improved, there is a problem that the weight increases due to an increase in the overall thickness and an increase in the length of the rear wheel shaft.

Therefore, an object of the present invention is to provide a vehicle rear arm which can prevent fretting without increasing the weight.

Another object is to prevent scratches on the surface of the arm portion of the rear arm.

[0011]

In order to achieve the above object, the invention according to claim 1 is for a vehicle which is mounted on a body frame so as to be vertically swingable and which supports a rear wheel so as to be vertically movable. In the rear arm, a connecting body swingably attached to the vehicle body frame, a front end portion fixed to the connecting body, a pair of left and right arm portions extended rearward, and arranged at rear end portions of the arm portions, A rear wheel shaft that rotatably supports the rear wheel, and an end portion through which the rear portion is formed, and the end portion forms a thick portion in a range in which the inner surface portion of the rear wheel is in surface contact with another component, It is characterized in that a rear arm for a vehicle is provided with a planar contact surface that comes into surface contact with the other component in the thick portion.

According to a second aspect of the present invention, in a vehicle rear arm that is swingably attached to a body frame in a vertical direction and supports a rear wheel so as to be vertically movable, a coupling that is swingably attached to the body frame. Body, a pair of left and right arm portions having a front end portion fixed to the connecting body and extended rearward, and rear wheel shafts rotatably supporting the rear wheel, which are arranged at rear end portions of the arm portions. The end portion is a vehicle rear arm having a coating applied to a contact surface of the inner surface portion on the rear wheel side that comes into surface contact with another component.

According to a third aspect of the present invention, in addition to the structure of the first aspect, a coating film is applied to the contact surface of the thick portion.

The invention according to claim 4 is the invention according to claim 2 or 3.
In addition to the configuration described in 1 above, a coating film is applied to the contact surface, and the other portion is anodized.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

[First Embodiment of the Invention] FIGS. 1 to 12
FIG. 3 is a diagram showing Embodiment 1 of the present invention.

First, the structure will be explained. In FIG.
2 is mounted and the front pipe 1 is attached to the head pipe 13 at the front of the vehicle body frame 11 via the front fork 14.
5, a rear wheel 17 is supported on the rear side of the vehicle body frame 11 via an aluminum rear arm 16 so as to be vertically swingable. The driving force of the engine 12 is transmitted to the rear wheel 17 side via the chain 18, and a rear cushion 19 is arranged between the rear arm 16 and the body frame 11. .

The rear arm 16 is provided on the right side of the rear wheel 17 as an "arm" when viewed from the rear side of the vehicle, and on the left side of the rear wheel 17 when viewed from the rear side of the vehicle. It has an arm left part 22 as an “arm part”,
The front end portion 2 of both the arm right portion 21 and the arm left portion 22
1a and 22a are fixed to a connecting body 23 located on the front side of the rear wheel 17.

The front end portion 23a of the connecting body 23 is
Is rotatably connected to the body frame 11, and the arm right part 21 and the arm left part 22 have rear end parts 21b,
End members 24 and 25 as "end portions" are fixed to 22b, and the rear wheel 17 is supported by these end members 24 and 25.

The right arm 21 of the connecting body 23
The lower end 19a of the rear cushion 19 is connected to the connecting body 23 at the portion between the front end 21a of the rear arm 22 and the front end 22a of the left arm 22.
9b is connected to the body frame 11.

The arm right part 21 and the arm left part 22
Is integrally formed in a tubular shape having a quadrangular cross section by bulging (hydroforming) as shown in FIG.
Here, "integrally molded in a tubular shape" means that the cut portion is not welded after cutting and thinning in order to change the cross-sectional shape in the longitudinal direction.

In this molding, an aluminum pipe having an elliptical cross section is inserted into a die provided on the outside, and pressure is applied to the pipe from the inside by a liquid to obtain a shape suitable for the inner surface of the die. This is completed by molding, then draining the liquid, and disassembling the mold to take out the molded arm right part 21 and molded arm left part 22. Note that FIG. 6 shows a split surface A of the mold in the case of the arm left portion 22.

As shown in FIG. 2, the right arm portion 21 and the left arm portion 22 extend along the vehicle width direction of the rear-side portions 21c, 22c near the rear side of the portion fixed to the connecting body 23. The lateral width W1 is formed to be wider than the lateral width W2 of the front end portions 21a and 22a and the lateral width W3 of the rear end portions 21b and 22b, and the rear closest portions 21c and 22c and the front end portion 21.
The width gradually changes between a, 22a and the rear end portions 21b, 22b.

As shown in FIG. 2, the right arm portion 21 and the left arm portion 22 are bent in a plan view so that the distance between the front end portions 21a and 22a is narrower than that at the rear side. As shown in FIG. 6, the vertical wall portion 22d on the inner side of the bent portion is not recessed inward, but is formed substantially along the vertical direction. Note that FIG. 6 shows the arm left portion 22.
About the vertical wall portion 21 of the arm right portion 21.
Similarly, d is also formed along the substantially vertical direction. Since a bent shape is also formed by hydroforming, there is no dent in the vertical wall portion caused by bending after swaging or spinning.

Further, as shown in FIGS. 3 and 4, the right arm portion 21 and the left arm portion 22 have a vertical width from H1 to H2 in a side view as they move rearward from the rear closest portions 21c and 22c. It is formed so as to become gradually narrower. As shown in FIG. 4, the right arm portion 21 has the maximum vertical width at the penetrating portion of the tubular body 26, and the vertical width decreases in front of this.

Furthermore, the front end portions 21a and 22a of the arm right portion 21 and the arm left portion 22 are fixed to a fixed portion 23b on the rear end side of the connecting body 23 by welding.

The connecting body 23 is formed of a cast metal into a hollow structure, and is welded in a state where the front ends 21a and 22a of the right arm 21 and the left arm 22 are in contact with each other, as shown in FIG. There is.

The tubular body 26 is passed through the arm right front end portion 21a and the connecting body 23, and the tubular body 27 is passed through the arm left front end portion 22a and the connecting body 23. The shaft 28 is attached to the coupling body 23 by being inserted through the shaft 28 and screwed into the nut 29 inserted from the other cylinder body 26 side. Further, the head portion 28a of the shaft 28 has a shape in which a part of a circular shape is cut out, and is designed to be prevented from rotating. As shown in FIG. 5, an arm relay 30 is rotatably attached to the shaft 28, and the lower end portion 19 a of the rear cushion 19 is attached to the arm relay 30.
Is rotatably attached. The arm relay 30 is rotatably connected to the vehicle body frame 11 via a rod connecting 31 (see FIG. 7). A cover member 32 is fitted into the cylindrical bodies 26 and 27 so that water or the like does not enter the inside of the coupling body 23.

The rear cushion 1 is attached to the connecting body 23.
A pair of left and right front end portions 23a is extended on both sides of the front end portion 2a so as to secure a space for arranging the front end portion 2a.
3a is provided with a through hole 23c extending in the vehicle width direction.
The rear arm 16 is swingably provided in the vertical direction by inserting the pivot shaft 34 along the vehicle width direction in the horizontal direction into the through hole 23c (see FIG. 8).

On the other hand, the arm right part 21 and the arm left part 22
At the rear end portions 21b and 22b of the open end, the end member 2
By inserting and welding the front end portions 24a and 25a of the end portions 4 and 25, the end members 24 and 25 are moved to the arm right portion 21.
It is also fixed to the rear ends 21b and 22b of the left arm portion 22.

The end members 24 and 25 are formed by forging, and as shown in FIGS. 3, 4 and 11, elongated holes 24b and 25b are formed along the vehicle front-rear direction and project sideward. Walls 24c and 25c are formed.

Further, the end members 24 and 25 have
As shown in FIG. 9, the long hole 24 is formed in the inner surface portion on the rear wheel 17 side.
Thickened portions 24d and 25d are formed in an annular shape around b and 25b, and these thickened portions 24d and 25d have contact surfaces 24e and 25e.
25e is formed in a planar shape. This thick part 24
d and 25d are formed in a range where they are in surface contact with other components (washers 42 and 43). In FIG. 11, the thick portion 25d of the end member 25 and the like are shown by diagonal lines, but the same applies to the end member 24.

Further, by coating the entire rear arm 16, the contact surface 2 of the thickened portions 24d, 25d is formed.
4e and 25e, as shown in FIG.
25f is formed, and the coating films 24f and 25f are attached to the contact surfaces 24e and 25e of the end members 24 and 25 and the washer 4 respectively.
It is arranged to intervene between 2 and 43.

Then, as shown in FIG.
The rear wheel shaft 37 is inserted through 4b and 25b and screwed into a nut 38, and the hub 40 of the rear wheel 17 is rotatably supported by the rear wheel shaft 37 via a bearing 41.

Further, the contact surface 24e of the thick portion 24d of the one end member 24 is brought into contact with the washer 42 via the coating film 24f, and this washer 42 is brought into contact with the disc brake device 44, and further, The disc brake device 44 is in contact with the bearing 41 via the spacer 48.

Further, the contact portion 25e of the thick portion 25d of the end member 25 on the opposite side is brought into surface contact with the washer 43 through the coating film 25f, and this washer 43 comes into contact with the bearing 41 through the spacer 49. There is.

In the figure, reference numeral 45 is a disk and reference numeral 46.
Is a color and reference numeral 47 is a sprocket.

In such a case, the right arm 2
As shown in FIG. 2, the first arm 1 and the arm left portion 22 have the horizontal width W1 of the rear closest portions 21c and 22c in the plan view as the horizontal width W2 of the front end portions 21a and 22a and the rear end portions 21b and 22c.
By forming the width b to be wider than the width W3, it is possible to set an optimum shape, wall thickness and the like, and it is possible to satisfy the rigidity and strength without increasing the weight. That is, since the front end portion 21a side is fixed to the connecting body 23 by welding, there is no problem in strength even if the lateral width W2 is short,
Further, since the bending moment acting on the right arm 21 and the left arm 22 becomes smaller as it goes rearward from the rear closest portions 21c and 22c, the rear end portions 21b and 22b.
The lateral width W3 on the side can be shortened. Then, the lateral widths W1, W2, W3 of the arm right part 21 and the arm left part 22 can be set according to the magnitude of the force, so that the rigidity and strength can be increased without increasing the weight. Can be satisfied.

Further, as shown in FIGS. 3 and 4, the right arm portion 21 and the left arm portion 22 have a vertical width from H1 to H2 in a side view as they go rearward from the rear closest portions 21c and 22c. Since it is gradually decreased, the heights of the right arm part 21 and the left arm part 22 can be set in accordance with the magnitude of the force, even in this point, without increasing the weight. The rigidity and strength can be satisfied.

Further, the arm right part 21 and the arm left part 2
Since 2 is bent in a plan view to narrow the distance between the front end portions 21a and 22a on the front side of the rear wheel 17,
The installation space S can be expanded, and this space S
It is possible to arrange other parts and the like and to secure foot contact. Moreover, the arm right part 21 and the arm left part 2
Since the vertical wall portions 21d and 22d on the inner side of the bent portion of 2 are along the vertical direction, the strength is secured by bending the square bar as compared with the vertical wall portions 21d and 22d which are recessed inward. it can.

By the way, as described above, the lateral width W2 of the rear closest portions 21c, 22c in plan view is set to the front end portion 21a,
22a and the rear end portions 21b and 22b can be formed wider than the lateral widths W1 and W2 and cannot be bent by the conventional methods such as spinning and swaging, but they can be formed by hydroforming as in the present invention. If
Since it is not necessary to remove the molds in the right arm part 21 and the left arm part 22, molding is possible.

Moreover, since it is not necessary to apply force by hitting or squeezing from the outside as in the conventional case, the right arm 2
1 and the surface of the left part 22 of the arm are not damaged,
No scratching process is required and the molding process can be reduced.

The thick members 24 are formed on the end members 24 and 25.
d and 25d are formed to improve the strength, and the contact surface 24e,
By making 25e a planar shape, the occurrence of fretting can be prevented. Moreover, the thick portions 24d and 25d
Is formed only in the portions that come into contact with the washers 42 and 43, so that the overall weight does not increase.

Further, since the contact surfaces 24e, 25e of the end members 24, 25 are coated with the coating films 24f, 25f, the film thickness is thicker and more flexible than the alumite. The relative movement between the contact surfaces 24e and 25e can be absorbed, and the metal contact between the two can be prevented, and in this respect also, the occurrence of fretting can be prevented.

Although the entire rear arm 16 may be painted as described above, the contact surface 2 of the end members 25 and 24 may be painted.
It is also possible to apply the coatings 24f and 25f only to 4e and 25e, and to anodize the other parts of the rear arm 16. In this way, the coating films 24f and 25f cannot be seen from the outside, and it can be recognized that the outer appearance of the rear arm 16 is made of aluminum, and the appearance quality can be improved.

Further, since the left arm portion 22 is set on the mold splitting surface A as shown in FIG. 6, it has the following advantages. That is, the inner lower corner portion a has the highest stress in the cross section, and if a step or the like is generated at this position due to the die splitting, it causes stress concentration.
The strength is secured by not setting. Also, since the outer upper corner b is the most conspicuous part,
The molding surface A is not set also in this corner portion B to ensure the appearance quality.

In the above embodiment, the end member 2
Although the reference numerals 4 and 25 are separate from the arm right part 21 and the arm left part 22, the end members 24 and 25 and the arm right part 21 are separated.
Alternatively, the left arm portion 22 may be integrated.

[Second Embodiment of the Invention] FIGS. 13 to 19
FIG. 7 is a diagram showing Embodiment 2 of the present invention.

In the second embodiment, as shown in FIG. 13, an end member 24 fixed to the arm right part 21 by welding and an end member 25 fixed to the arm left part 22 by welding on the rear wheel 17 side. Long holes 24b, 25b on the inner surface
Patches 50 and 51 formed in an annular shape are screwed and fixed to the peripheral edge of with a flat head screw 52. These patch 5
0 and 51 correspond to the washers 42 and 43 of the first embodiment.

As shown in FIGS. 14 to 17, the end members 24 and 25 have a planar inner surface on the rear wheel 17 side and are formed with elongated holes 24b and 25b along the vehicle front-rear direction. Two screw holes 24g and 25g into which the flat head screw 52 can be screwed are threaded on the periphery of the elongated holes 24b and 25b on the vehicle rear side.

The patches 50 and 51 provided on the end members 24 and 25 surround the peripheral edges of the long holes 24b and 25b of the end members 24 and 25, respectively, as shown in FIGS. The contact surfaces 50a and 51a that contact the end members 24 and 25 and the contact surfaces 50b and 51b that contact other components are formed in a plane shape in a ring shape in the area of surface contact. Further, two counterbored holes 50c, 51c are formed so that the screw heads of the countersunk screws 52 do not protrude from the contact surfaces 50a, 51a when the patches 50, 51 are attached to the end members 24, 25 with the countersunk screws 52. .

Further, the patches 50 and 51 are provided with coating films 50d and 51d as a surface treatment.
For 51d, for example, a solid lubricant such as a molybdenum disulfide-based fluororesin having an anti-fretting action is used. The thickness of the coating films 50d and 51d is 35 ± 5 μm on the contact surfaces 50a and 51a, and the thickness of the other portions is 15 μm.

In such a case, the end member 2
By fixing the patches 50, 51 to 4, 25 to improve the strength and making the contact surfaces 50b, 51b flat, it is possible to prevent the occurrence of fretting.

Further, since the patches 50 and 51 are provided with the coating films 50d and 51d having the function of suppressing fretting, the occurrence of fretting can be prevented in this respect as well.

The other structure and operation are the same as those of the first embodiment of the invention, and the duplicated description will be omitted.

[0056]

As described above, according to the invention described in claim 1, there is an end portion arranged at the rear end portion of the arm portion, and the end portion is an inner surface on the rear wheel side. Since a thick part is formed in the range where the part comes into surface contact with other parts, and a flat contact surface that comes into surface contact with other parts is provided in this thick part, strength can be improved by the thick part. The contact surface can be maintained in a flat shape, and fretting can be prevented from occurring. Moreover, since the thick portion is formed only in the portion that comes into contact with other components, the weight of the entire portion does not increase.

According to the second aspect of the present invention, the end portion arranged at the rear end portion of the arm portion is the inner surface portion on the rear wheel side,
Since the coating film is applied to the contact surface that comes into surface contact with other components, this coating film has elasticity, and thus fretting can be prevented from occurring.

According to the invention of claim 4, claim 2
Alternatively, in addition to the constitution described in 3, a coating film is applied to the contact surface,
Since the other part is anodized, its coating film is provided only on the contact surface of the end member, and the other part of the rear arm is anodized, so the coating film cannot be seen from the outside and the appearance of the rear arm It can be recognized that is made of aluminum, and the appearance quality can be improved.

[Brief description of drawings]

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

FIG. 2 is a plan view of the rear arm according to the first embodiment.

FIG. 3 is a side view seen from the direction of arrow A in FIG. 2 according to the first embodiment.

FIG. 4 is a side view seen from the direction of arrow B in FIG. 2 according to the first embodiment.

FIG. 5 is a cross-sectional view taken along line CC of FIG. 2 according to the first exemplary embodiment.

FIG. 6 is a sectional view taken along line DD of FIG. 2 according to the first embodiment.

FIG. 7 is a side view showing a front end side and a rear cushion of the rear arm according to the first embodiment.

FIG. 8 is a sectional view taken along the line DD of FIG. 7 according to the first embodiment.

FIG. 9 is an enlarged cross-sectional view taken along the line EE of FIG. 1 according to the first embodiment.

FIG. 10 is a plan view of an end member of the rear arm according to the first embodiment.

FIG. 11 is a side view showing the end member of the rear arm according to the first embodiment, as seen from the direction of arrow F in FIG. 10.

FIG. 12 is an enlarged view of an X portion of FIG. 9 according to the first embodiment.

FIG. 13 is a plan view of a rear arm according to the second embodiment of the present invention.

FIG. 14 is a plan view of an arm right end member of the rear arm according to the second embodiment.

FIG. 15 is a side view showing the arm right end member of the rear arm according to the second embodiment, as viewed from the direction of arrow G in FIG.

FIG. 16 is a plan view of an end member on the left side of the arm of the rear arm according to the second embodiment.

FIG. 17 is a side view showing the end member on the left side of the arm of the rear arm according to the second embodiment of the present invention as viewed in the direction of arrow H in FIG. 16;

FIG. 18 is a plan view of the patch according to the second embodiment.

FIG. 19 is an enlarged sectional view taken along the line JJ of FIG. 16 according to the second embodiment.

[Explanation of symbols]

11 Body frame 16 Rear arm 17 rear wheel 21 Arm right part (arm part) 22 Arm left part (arm part) 21a, 22a Front end 21b, 22b rear end 21c, 22c posterior site 23 Connected body 24,25 End member (end part) 24d, 25d thick part 24e, 25e, 50b, 51b Contact surface 24f, 25f, 50d, 51d coating film 37 rear axle 42,43 Washers (other parts)

Claims (4)

[Claims] 1. A rear arm for a vehicle, which is swingably attached to a body frame in a vertical direction and supports a rear wheel so as to be vertically movable, and a connecting body which is swingably attached to the body frame, and the connecting body. It has a pair of left and right arm portions whose front end portions are fixed and extended rearward, and end portions which are arranged at the rear end portions of the arm portions and through which rear wheel shafts for rotatably supporting the rear wheels are inserted. The end portion has a thick-walled portion formed on the inner surface portion on the rear wheel side in a range in which it comes into surface contact with another component, and the thick-walled portion is provided with a planar contact surface that makes surface-contact with the other component. Rear arm for vehicles characterized by. 2. A rear arm for a vehicle, which is swingably attached to a body frame in a vertical direction and supports a rear wheel so as to be vertically movable, and a connecting body swingably attached to the body frame, and the connecting body. It has a pair of left and right arm portions having a front end portion fixed and extended rearward, and an end portion which is arranged at the rear end portions of the arm portions and through which a rear wheel shaft for rotatably supporting the rear wheel is inserted. The rear arm for a vehicle, wherein the end portion has a coating film applied to a contact surface of the inner surface portion on the rear wheel side that comes into surface contact with another component. 3. The vehicle rear arm according to claim 1, wherein a coating film is applied to a contact surface of the thick portion. 4. The rear arm for a vehicle according to claim 2, wherein a coating film is applied to the contact surface and the other portion is anodized.