JPH03136993A - Swing arm of motorcycle - Google Patents

Abstract

PURPOSE:To obtain a swing arm which can be manufactured easily and at a low cost by providing two connecting members to a body part at positions with different heights, incorporating them by casting, and forming the arms almost linearly by a plastic process and connecting their front ends by welding to the connecting members. CONSTITUTION:A swing arm 15 is manufactured by forming a complicated shape of a body part 51 having arm connections 55L and 55R in a casting process which has a large degree of freedom, arms 52L and 52R in a simple drawing process, and holding pieces 58L and 58R in a forging, and fixing the front ends of the arms 52L and 52R to the body part 51 by welding, welding the holding pieces 58L and 58R to the rear ends of the arms 52L and 52R, and furthermore, extending a subarm 61 between the body part 51 and the holding pieces 58L. In such a way, a complicated shape of swing arm 15, that is, a swing arm 15 in which the heights of the arms 52L and 52R from the ground are made different at some parts, can be manufactured easily and at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a swing arm used in a rear wheel suspension system of a motorcycle.

(Prior Art) In general, motorcycles have a swing arm that supports the rear wheel, an engine that is mounted approximately at the center of the vehicle body frame in the vehicle width direction, and an exhaust pipe that is passed through the lower part of the swing arm to the rear and rearward. The swing arm extends outward on one side in the vehicle width direction. However, in such a motorcycle, the exhaust pipe is located below the swing arm, and the height of the exhaust pipe from the ground is low, which may cause the exhaust pipe to limit the bank angle (camber angle).

Therefore, Japanese Patent Laid-Open No. 1-141188 has proposed a motorcycle whose purpose is to increase the height of the exhaust pipe above the ground. In the motorcycle disclosed in Japanese Unexamined Patent Application Publication No. 1-141188, the arm portion of the swing arm is formed into a substantially V-shape when viewed from the side, and an exhaust pipe is passed below the V-shape bent portion.

(Problem to be Solved by the Invention) However, in the swing arm described in the above-mentioned publication, the entire swing arm is integrally molded together with the bent arm portion, which makes molding difficult and costly. There is a problem in that it leads to an increase in

This invention was made in view of the above-mentioned problems, and aims to provide a swing arm that can be manufactured easily and at low cost.

(Means for Solving the Problems) A first invention includes a body part attached to a vehicle body and a pair of left and right arm parts extending rearward from the body part and supporting a rear wheel between rear ends, and one of the left and right arm parts. In a swing arm for a motorcycle in which the ground height of one arm part is larger than the other arm part, two connecting parts are provided in the body part at different height positions, and the body part is cast together with the connecting parts. The gist is characterized in that each of the arm parts is formed substantially straight by plastic working, and the front end is welded to the connecting part. A motorcycle comprising a body part and a pair of left and right arm parts extending rearward from the body part and supporting a rear wheel between the rear ends, the ground height of one arm being partially higher than the other arm part. In the swing arm, a first divided body having a part of the body portion and one arm portion and a second divided body having the remainder of the body portion and the other arm portion are each integrally formed by casting, and these are integrally formed by casting. The gist is that it is characterized by being formed by welding the divided bodies together.

(Function) In the swing arm according to the first invention, in order to make the height above the ground at the point where one arm portion is connected to the body portion larger than the point where the other arm portion is connected, a corresponding portion is placed below the arm portion. A space is secured and the exhaust pipe can be passed through the space, and the height of the exhaust pipe above the ground can be increased to increase the bank angle. Then, the body part, which has an asymmetrical shape on the left and right sides, is formed by casting, which has a high degree of freedom in shaping, and the arm parts are formed into a nearly straight shape by plastic processing such as drawing, and these arm parts are simply welded to the connecting part of the body part. To complete the swing arm,
Its manufacture is cheap and easy.

In addition, since the swing arm of the second invention is molded by casting into divided bodies each having an arm part, there is a large degree of freedom in shaping, and the height above the ground of one arm part can be made larger than the other arm part. The bank angle can be increased similarly to the first invention described above. Further, since it can be completed by simply welding the cast-formed divided bodies together, it can be manufactured easily and at low cost.

(Implementation) Hereinafter, embodiments of this invention will be described with reference to the drawings.

1 to 9 show a swing arm of a motorcycle according to a first embodiment of the first invention, in which FIG. 1 is a left side view of the motorcycle, FIG. 2 is a right side view thereof, and FIG. 3 is a swing arm of a motorcycle according to a first embodiment of the first invention. is an enlarged plan view of the same part, Fig. 4 is an enlarged side view of the same part, Fig. 5 is an enlarged side view of a part of the holding part, Fig. 6 a, b, and c are detailed views of the swing arm, and Fig. 7 is a partially cutaway cross-sectional view of the air cleaner.
Figure 8 a, b, c are detailed views of the rear cowl, Figure 9 a, b
, c are detailed views of the pillion seat.

In FIGS. 1 and 2, 11 is a twin tube type main frame made of cast aluminum alloy, etc.
A head tube 12 is fixed to the front end of the main frame 11, and a front wheel 14F is supported by a front fork 13 so that it can be steered.A rear wheel 14R is supported by a swing arm 15 at the lower part of the rear end so that it can move up and down. A seat frame 18 made up of pipe-shaped members is fixed to the upper end. The swing arm 15 will be described in detail later, but this swing arm 15 includes a main frame 1.
A well-known cushion unit 17 is interposed between the upper rear end of the cushion unit 1 and the upper rear end of the cushion unit 1 via a progressive link mechanism 16.

A rear fender 19 and a rear cowl 20 made of synthetic resin are fixed to the seat frame 18, and the rear cowl 20 covers the upper part of the rear fender 19. rear cowl 20
As shown in detail in FIG. 5, the upper panel 21 is formed by joining an upper panel 21 which is generally in the shape of a mouth when viewed from the side, and a pair of left and right side panels 22L and 22R, and a bulge portion 20a that projects upward is formed at the rear. There is. In this rear cowl 20, a driver seat 23 is mounted on the front part, a pillion seat 24 is mounted on the upper panel 21 on the rear bulge 20a, and the upper panel 2
A seat back 25 is fixed to the front of the seat 1. The pillion root 24 has PvC as shown in FIG.
Belt insertion holes 26L, 26R are formed on both sides of the front part, and a bracket 2 with a nut 27 welded to it is embedded in the lower center of the rear part. This pillion seat 24 has belt insertion holes 26L and 26R at the front.
It is fixed to the rear cowl 20 with a belt 29 that passes through it, and the rear part is fixed to the rear fender 19 with a bolt 30 that is screwed into a nut 27, as shown in FIG. In addition, in FIG. 9C, 99 is a tool box supported by the seat frame 18, and the upper panel 21 is installed on the tool box 99 via a rubber cushion 98 made of rubber or the like.

As shown in detail in FIGS. 8a, b, and c, the upper panel 21 has concave portions 32L formed by inclined walls that slope outward in the vehicle width direction on both left and right sides of the front portion of the upper surface.

32R is formed, and the ventilation holes 31 are formed in the recesses 32L and 32R.
L, 31R are formed, and a recess 33 is formed at the center of the upper surface by an inclined wall that slopes toward the rear.
An exhaust hole 34 is formed in 3. This upper panel 2
1, as shown in FIG. 5, a belt 29 is inserted through each of the exhaust holes 31L and 31R, and a bolt 30 for attaching the pillion seat 24 described above is inserted through the exhaust hole 34.

As shown in FIG. 9C, the belt 29 is inserted through the belt insertion holes 26L and 26R of the pillion seat 24, and both ends thereof are fixed to both sides of the rear cowl 20.

Further, a fuel tank 35 is mounted on the main frame 11 at approximately the upper center, and a V-type two-cylinder two-stroke engine 36 is suspended at the approximately lower center. Carburetor 38, control valve 39 and air cleaner 40 are shown above.
is installed. The engine 36 is assembled integrally with a transmission, and the output shaft of the transmission protrudes to the left. As shown in FIGS. 3 and 4, a driving sprocket 41 is fixed to this output shaft, and the output shaft is connected to the rear wheel 14R by a chain 42 that is hooked around the driving sprocket 41 so as to be capable of transmitting power. In this engine 36, one row of cylinders protrudes upward and the other row of cylinders protrudes forward, and exhaust pipes 43L and 43R extend rearward from these cylinder rows through below the engine 36, respectively. As shown in detail in FIGS. 3 and 4, these exhaust pipes 43L and 43R each have a diff user part 44L and 44R at a position a predetermined distance mm away from the cylinder row, and the exhaust pipes 43L and 43R have diff user portions 44L and 44R, respectively, at positions separated from the cylinder row by a predetermined distance, and the exhaust pipes 43L and 43R have diff user portions 44L and 44R, respectively, at positions separated from the cylinder row by a predetermined distance. The pipe 43L positions the differential user part 44L below the engine 36 and extends rearward on the left side of the rear wheel 14R, and the exhaust pipe 43R of the cylinder row that projects forward is connected to the front end of the arm part of the swing arm 15, which will be described later. It is located below and extends rearward on the right side of the rear wheel 14H. 60L and 60R are mufflers provided in the exhaust pipes 43L and 43H.

The carburetor 38 consists of a well-known venturi type carburetor provided with an air jet opening into an intake passage.The intake passage is connected to an air cleaner 4o, and the air jet is connected to an air cleaner 40 via a control valve 39. The air cleaner 4° is connected to the upper body 4 as shown in Fig. 7.
5 and a lower body 46 are assembled via an element 47, and an intake side chamber 48 opened to the atmosphere is provided between the element 47 and the upper body 45, and a carburetor is inserted between the element 47 and the lower body 46. A supply side chamber 49 in communication with 38 is defined. The upper half body 45 and the lower body 46 each have a partition wall 45a on their inner surfaces.

46a are integrally provided to protrude, and these partition walls 45a.

46a is in contact with the element 47, and between the element 47 and the small chambers 48a and 49, the chambers 48a and 49 are separated from each other.
, 49a. A small chamber 49a defined between the partition wall 46a of the lower body 46 and the element 47 is connected to the control valve 39 via a hose connected to the nipple 50. This air cleaner 40 has a chamber 4.
Clean air is passed through element 47 from room 49 to room 49.
from the chamber 49 to the intake passage of the carburetor 38, and from the small chamber 49a to the air jet of the carburetor 38 via the control valve 39. Therefore, the carburetor 38 is not affected by pulsations in the air ejected from the air jet.

The swing arm 15 is a so-called double-supported swing arm, as shown in detail in FIGS. arm part 52L.

52R. The body part 51 is integrally formed by casting, and has a hole 5 for arranging a cushion unit in the center in plan view.
3, a support hole 54 penetrating left and right in the front part, arm coupling parts 55L and 55R on both left and right sides, a bracket part 56 projecting upward behind the hole 53 at the top, and a progressive link connection at the bottom. A boss portion 57 is formed. The right arm portion 55R has a substantially curved shape when viewed from the side, and the left arm portion 55L
has a substantially straight shape, and these arm connecting portions 55L, 55
R has a different ground height at the rear end and is the right arm joint 55R.
is formed at a higher position than the left arm coupling portion 55L. This body portion 51 has a support shaft (not shown) inserted through a support hole 54, and the main frame 11 is supported by the support shaft.
A hole 57a is formed in the boss portion 57, and the aforementioned progressive link mechanism 16 is connected to a bottle (not shown) inserted into the hole 57a, and the progressive link mechanism 16 is connected to the hole 53. A cushion unit 1f is arranged, and the front ends of arm parts 52L and 52R are welded to the rear ends of arm joint parts 55L and 55R, respectively.

The arm parts 52L, 52R are formed substantially straight by plastic processing such as extrusion or drawing, and as described above, the front ends are connected to the arm connecting parts 55L, 5 at different heights above the ground of the body part 51.
Support pieces 58L and 58R are welded and connected to the rear end of 5R, and support pieces 58L and 58R are fixed by welding at a ground height equal to the rear end.
In between, the rear wheel 14R and a driven sprocket 59 are supported by an axle. As shown in FIG. 6, the left arm portion 52L extends linearly between the support hole 54 and the support piece 58L, that is, between the rotation centers of the sprocket 41.59,
As shown in FIG. 6C, the right arm portion 52R extends rearward and downward and has a space below its front end. As shown in FIGS. 2 and 3, the differential user section 44R of the exhaust pipe 43R is located below the front end of the right arm section 52R.

The swing arm 15 also includes a bracket portion 56 of the body portion 51 and a support piece 58L above the left arm portion 52L.
A substantially rod-shaped sub-arm 61 is installed between the two. This sub-arm 61 has a front end curved inward and fixed by welding to the upper left side of the bracket part 56, and a rear end inclined backward and fixed by welding to the upper part of the support piece 58L. This sub-arm 61 has a considerable space 62 (
4), and the aforementioned chain 42 is hung through this space 62.

In the motorcycle of this embodiment, the swing arm 1
5, the height above the ground near the front end of the right arm portion 52R is greater than that of the left arm portion 52L;
Diff user part 4 of exhaust pipe 43R is located downward near the front end of R.
Position 4R.

Therefore, the minimum ground height differential user portion 44R1 of the exhaust pipe 43R, that is, the height above the ground of the differential user portion 44H is large, and the puncture angle can be increased. In addition, the left arm portion 52L of the swing arm 15 has a sprocket 41.59.
The left arm portion 52L extends linearly between the rotation centers of the
Since the sub-arm 61 is arranged in parallel with the sub-arm 61 and the arm portion 52L is reinforced by the sub-arm 61, great rigidity against the churn 42 can be obtained.

On the other hand, this swing arm 15 has an arm coupling portion 55L.
, 55R is formed by casting, which allows a large degree of freedom in shaping, the arm parts 52L, 52R are formed by simple drawing, and the support pieces 58L, 58R are formed by forging. The front ends of 52L and 52R are fixed by welding, and a support piece 58L is attached to the rear end of arm parts 52L and 52R.

58R is welded, and the sub-arm 61 is attached to the body part 5.
1 and the support piece 58L. Therefore, a swing arm 15 having a complex shape as in this embodiment, that is, a swing arm 15 in which the arm portions 52L and 52R have partially different ground heights, can be easily and inexpensively manufactured.

Figures 10 to 14 show a second embodiment of the first invention, with Figure 10 being a left side view of the motorcycle, Figure 11 being a right side view of the same, and Figure 12 being a partially enlarged left side view. , FIG. 13 is a partially enlarged plan view.

In addition, in this second embodiment and the embodiments to be described later, the same parts as in the above-mentioned embodiment are given the same reference numerals, and the explanation will be simplified.

In the figure, 11 is the main frame, 12 is the Herad tube,
13 is the front fork, 14F is the front wheel, 18 is the seat frame, 19 is the rear fender, 20 is the rear cowl, 2
3 is a driver seat, 24 is a pillion seat, 35 is a fuel tank, 64 is a 4-stroke 4-cylinder engine, 37 is a radiator, 38 is a carburetor, 40 is an air cleaner, 15 is a swing arm, 14R is a rear wheel, 16 is a progressive brake The link mechanism 17 is a cushion unit.

The engine 64 is assembled to the transmission and the body, and the transmission is attached to the right chain 4 located on the left side.
2 is connected to the rear wheel 14R. An intake manifold 65 connects each cylinder of the engine 64 to the engine 6.
4, these intake manifolds 65
is connected to a collecting pipe 66 located below the engine 64. The exhaust pipe 6 has a muffler 67 in the collecting pipe 66.
8 is connected, and an exhaust pipe 68 extends rearward on the right side of the rear wheel 14R through the lower front end of the arm portion of the swing arm 15.

The swing arm 15 has a front end swingably attached to the main frame 11, a rear end supporting the rear wheel 14R, and a cushion unit connected to the upper rear end of the main frame 11 via a progressive link mechanism 16. 1F is provided. This swing arm 15 is also shown in FIGS.
As shown in detail in c, a body part 51 formed by casting,
It has a pair of left and right arm portions 52L, 52R formed substantially straight by extrusion or drawing, and support pieces 58L, 58R formed by forging. The body part 51 has a support hole 54 at the edge through which a mounting shaft is inserted, a boss part 57 for coupling with the progressive link mechanism 16 at the rear of the hole 53 at the upper part, and a boss part 57 at the upper part at the rear of the hole 53. The boss portion 57 for coupling with the productive link mechanism 16 is located at this position.
A bracket part 56 is formed at the rear position of 7, and arm parts 52L and 52R are formed on both rear sides. Similar to the embodiment described above, the right arm portion 52R has a higher height above the ground than the left arm portion 52L.

The front ends of the arm portions 52L and 52R are the arm portion 5.
It is welded to the rear ends of 2L and 52R, and a support piece 58 is attached to the rear end.
L and 58R are welded together, and the rear wheel 14R is supported between the support pieces 58L and 58R. As is clear from Figure 14,
The right arm portion 52R has a front end higher in height from the ground than the left arm portion 52L, and its cross-sectional dimension (vertical).

(lateral) is larger than the left arm portion 52L and has greater rigidity than the left arm portion 52L. This right arm part 5
The rigidity or dimension of 2R is determined to be approximately equal to the rigidity of the left arm portion 52L reinforced by the sub-arm 61.

The sub-arm 61 is formed by integrally molding a substantially triangular plate part 7o that is arranged upright along the arm part 52L and an arm part 71 that protrudes from the upper front end of the plate part 70 and curves inward. ing. The tip of the arm portion 71 is welded to the upper end of the bracket portion 56 of the body portion 51, and the lower edge of the plate portion 7o is welded to the upper portion of the arm portion 52L, and the rear end is welded to the upper portion of the support piece 58L. . This sub-arm 61 has a space 62 between the lower part of the arm part 1 and the upper part of the body part 51, and the aforementioned chain 42 is hung through this space 62.

In this motorcycle, the front end of the right arm portion 52R of the swing arm 15 has a large height above the ground, and the collecting pipe 6
Since the exhaust pipe 68 extending from the swing arm 68 is arranged below the substantially front end position of the right arm part 52R of the swing arm 15, the height of the exhaust pipe 68 from the ground can be increased, and the bank angle is not limited by the exhaust pipe 68. I won't even receive it. Further, in the swing arm 15, a left arm portion 52L is disposed on the same side as the chain 42 and extends linearly between the rotation centers of the sprockets 41 and 59, and this arm portion 52L is connected to the sub arm 61.
, the rigidity of the chain 42 can be increased. The swing arm 15 is also easy to manufacture because the body portion 51 is formed by forging, the arm portions 52L and 52R are formed by drawing, and these are joined together by welding. Furthermore, since the arm parts 52L and 52R of this swing arm 15 are formed by drawing,
It is also easy to change its dimensions (rigidity), and even if the sub-arm 61 is provided, the left and right rigidities can be easily balanced.

15 to 19 show an embodiment of the second invention,
Fig. 15 is a left side view of the motorcycle, Fig. 16 is a right side view thereof, Fig. 17 is an enlarged side view of the same part, Fig. 18 is an enlarged plan view of the same part, and Fig. 19a.

b, c, d, e are detailed views of the swing arm.

In the figure, 11 is the main frame, 12 is the Herad tube,
13 is the front fork, 14F is the front wheel, 18 is the seat frame, 20 is the rear cowl, 23 is the driver seat,
24 is a pillion seat, 35 is a fuel tank, 64 is a 4-cycle 4-cylinder engine, 37 is a radiator, 38 is a carburetor, 40 is an air cleaner, 15 is a swing arm, 14R is a rear wheel, 16 is a progressive link mechanism, 1
7 is a cushion unit. As described in each of the above embodiments, the engine 64 is assembled integrally with the transmission and connected to the rear wheel 14R by the chain 42 disposed on the left side, and also has intake manifolds extending from each cylinder of the engine 64. 65 is connected to the collecting pipe 66. A collecting pipe 66 is located below the engine 64 , and an exhaust pipe 68 having a muffler 67 is connected to the right arm portion 52 of the swing arm 15 from the collecting pipe 66 .
It extends rearward on the right side of the rear wheel 14R via the lower front end of the rear wheel 14R.

The swing arm 15 is shown in FIGS. 19a, b, and c.

As shown in detail in d and e, it has a body part 51 and a pair of left and right arm parts 52L, 52R, and the body part 51 is divided at the center as a dividing plane to form arm parts 52L, 5, respectively.
It is constructed by welding together two divided bodies 73L and 73R having 2R.

These divided bodies 73L, 73R have a support hole 54L at the front end,
54R is formed to form a support hole 54L.

A vibrator member 74 whose end portion is fitted to the support hole 54R is installed between the front ends, and a large diameter cylindrical portion 75L, ? 5R and small diameter cylindrical part 76
L, 76R are formed, and these cylindrical parts 75L, 75R
, 76L, and 76R are fitted and welded together, and the body portion 51 is constituted by the pipe member 74 and the cylindrical portions 75L, 75R, 76L, and 76R. Further, these divided bodies 73L, 73R constitute arm portions 52L, 52R at the rear portions of the cylindrical portions 75L, 75R, and elongated holes 78L, 78R are formed at the rear ends, and the axle shafts are inserted into the elongated holes 78L, 78R. The right divided body 73ft is bent upward in a substantially rectangular shape when viewed from the side, with the top near the portion where the cylindrical portion 76R is formed, and below this bent portion. A collecting pipe 66 is disposed at. The left divided body 73L is the sprocket 41 of the chain 42.
It extends substantially linearly between 59 and 59.

Furthermore, the left divided body 73L has cylindrical portions 75R and 78R.
An insertion hole 79L is formed therebetween, and a sub-arm portion 80 is integrally formed therebetween, and a screw hole 79R is formed in the right divided body 73R. Screw hole 79R of divided body 73R and divided body 73
The L insertion hole 79L is located coaxially with the L insertion hole 79L as shown in FIG. 19(d), and is connected to the progressive link mechanism 16 by a bolt shaft that passes through the insertion hole 79L and is screwed into the screw hole 79R. The sub-arm part 80 is formed integrally with the divided body 73L, and has a substantially triangular plate-shaped main body 81 erected on the upper part of the divided body 73L, and between the front end upper part of the main body 81 and the upper part of the cylindrical part 76L of the divided body 73L. It has a bridged arm portion 82. A space is provided between the arm portion 82 and the body portion 62 below, and the chain 42 is hung through the space 62.

Even in such a swing arm 15, the right divided body 73R, that is, the arm portion 52R is bent in a substantially rectangular shape, and the exhaust pipe 68 extending from the exhaust manifold pipe 66 is provided below the bent portion. Because of this, the height of the exhaust pipe 68 above the ground can be increased, and the bank angle can be increased. The left divided body 73L, that is, the arm portion 52L has a sprocket 41.5.
Since the chain 4 is arranged linearly between the rotation centers of the chain 4
The rigidity can be increased compared to 2.

Moreover, this swing arm 15 is composed of two divided bodies 73L.
, 73R are molded by casting, which has a high degree of freedom in shaping, and these divided bodies 73L and 73R are welded together to complete the manufacturing process, which facilitates manufacturing and reduces manufacturing costs.

(Effects of the Invention) As explained above, according to the swing arms of the first and second inventions of the present application, the height of the exhaust pipe above the ground can be increased, the rigidity of the wrapped transmission element can be increased, and , it can be manufactured easily and inexpensively.

[Brief explanation of the drawing]

1 to 9 show a first embodiment of the first invention, in which FIG. 1 is a left side view of the motorcycle, FIG. 2 is a right side view of the same, FIG. 3 is an enlarged plan view of the same part, Figure 4 is an enlarged side view of the same part.
Figure 5 is an enlarged side view of a part of the air cleaner, Figure 6a is a plan view of the swing arm, Figure 6 is a left side view of the same, Figure 6C is a right side view of the same, Figure 7 is a part of the air cleaner. Fig. 8A is a plan view of the upper plate of the rear cowl, Fig. 8 is a side view with the same part cut away, Fig. 8C
is a sectional view taken along the arrow ■-■ of Fig. 8a, Fig. 9a is a side sectional view of the pillion seat, Fig. 9 is a plan view of the same, and Fig. 9C is a sectional view of the pillion seat.
Fig. alX-■ is a sectional view taken along the arrow. 10 to 14 show a second embodiment of the first invention, in which FIG. 10 is a left side view of the motorcycle, FIG. 11 is a right side view of the same, FIG. 12 is a partially enlarged side view of the same, Fig. 13 is an enlarged plan view of the same part, Fig. 14a is a plan view of the swing arm, Fig. 14 is a left side view of the same, and Fig. 14C is a right side view of the same. 15 to 19 show an embodiment of the second invention,
Fig. 15 is a left side view of the motorcycle, Fig. 16 is a right side view, Fig. 17 is an enlarged side view of the same part, Fig. 18 is an enlarged plan view of the same part, and Fig. 19a is a plan view of the swing arm. , 1st
Figure 9 is the same left side view, Figure 19C is the same right side view, and Figure 19 is the same left side view.
Figure d is a cross-sectional view of Figure 19 b (7) IXXd-IXXd, and Figure 19 e is a cross-sectional view of Figure 19 IXX e-IX
It is a sectional view taken along the arrow e. 5... Swing arm 6... Engine 3L, 43R... Exhaust pipe 4L, 44R... Differential user part 1... Body part 2L, 52R... Arm part 5L, 55R... Arm coupling part 1...Sub arm 4...Engine 8...Exhaust pipe 3L, 73R...Split body patent

Claims (2)

[Claims] (1) A body part that is attached to the vehicle body and a pair of left and right arm parts that extend rearward from the body part and support the rear wheels between the rear ends. In a swing arm for a motorcycle that is larger than an arm portion, two connecting portions are provided at different heights on the body portion, and the body portion and the connecting portion are integrally formed by casting,
A swing arm for a motorcycle, characterized in that each of the arm parts is formed substantially straight by plastic working, and a front end is welded to the connecting part. (2) A body part that is attached to the vehicle body and a pair of left and right arm parts that extend rearward from the body part and support the rear wheels between the rear ends. In the swing arm of a motorcycle that is higher than the body part, the first swing arm has a part of the body part and one arm part.
A swing arm for a two-wheeled motor vehicle, characterized in that the divided body and a second divided body having the remainder of the body portion and the other arm are integrally formed by casting, and these divided bodies are joined by welding.