JPH06316Y2 - Swing arm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a swing arm for a vehicle having two rear wheels. More specifically, the front ends of a pair of arm members are pivotally attached to a body frame while The present invention relates to a swing arm in which a cross member is bridged between end portions, and a support portion which supports a rear wheel axle is joined to the cross member via a projecting piece.

[Background of the Invention] In a small vehicle such as a motorcycle, a rear wheel is supported by a swing arm pivotally mounted on a body frame.
A front end of this swing arm is pivotally attached to a vehicle body frame, and a rear wheel axle is supported at a rear end of the swing arm. In addition,
A suspension is interposed between the swing arm and the body frame, and vibrations of the vehicle during traveling are effectively damped by the elastic force of the suspension and the swing of the swing arm.

By the way, in the case of a vehicle having two rear wheels, a considerable torsional load is applied to the swing arm during traveling on a curve or the like. Therefore, in such a vehicle, the swing arm has a structure with higher rigidity than the motorcycle (see No. 61-191987).

Therefore, FIG. 1 shows the configuration of a swing arm for a vehicle having two rear wheels according to the prior art. In the figure, reference numeral 2 indicates a swing arm, and the swing arm 2 has a pair of arm members 4 and 6, and the front ends of these arm members 4 and 6 are pivotally attached to a body frame (not shown). In this case, cross members 8 and 10 for reinforcement are bridged between the front end portions of the arm members 4 and 6 and the intermediate portion near the rear end portion, and are joined by welding or the like, respectively. A cylindrical bearing 12 is joined to the rear ends of the arm members 4 and 6, and the axle insertion hole of this bearing 12 is joined.
A rear wheel axle (not shown) is supported at 14. Further, the arm members 4 and 6 and the support portion 12 are provided with a reinforcing plate 16a.
Through 16d.

The swing arm 2 configured as described above is provided with the arm member 4
And cross members 8 and 10 bridged between and
The reinforcing members 16a to 16d for connecting the arm members 4 and 6 and the support portion 12 ensure rigidity against a torsional load and the like. However, this swing arm 2 requires a large number of constituent members including the reinforcing plates 16a to 16d, and has a drawback that it takes a long time for the assembling work. Therefore, it is expensive and becomes a cause of hindering the improvement of the yield.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned inconvenience, and bridges a cross member between the rear ends of a pair of arm members whose front ends are pivotally attached to the vehicle body frame. Long welding parts provided on both sides of the cross member are joined along the respective arm members, and a pair of projecting pieces are provided along the shaft of the support part for supporting the axle of the rear wheel. By sandwiching and joining the rear end portions of the pair of arm members and the cross member by the projecting pieces, the number of constituent members is reduced, assembly work time is shortened, cost is reduced, and sufficient force against external force is exerted. An object of the present invention is to provide a swing arm capable of obtaining rigidity.

[Means for Achieving the Object] In order to achieve the above object, the present invention provides a swing arm for supporting a rear wheel of a vehicle having two rear wheels, the front end of which is pivotally attached to a vehicle body frame and is swingable. A pair of arm members, and a cross member that extends along the arm member, has welded portions welded to the arm member on both sides, and bridges between rear end portions of the arm members; A bearing that extends in the vehicle width direction of the vehicle, has a pair of projecting pieces that are welded while sandwiching both the rear ends of the pair of arm members and the cross member, and supports the axle of the rear wheel. And a section.

[Embodiments] Next, preferred embodiments of the swing arm according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 2, reference numeral 20 denotes a small four-wheel vehicle to which the swing arm according to the present embodiment is attached. The small four-wheel vehicle 20 has a body frame 22 as a skeleton and front wheels 24a, 24b and rear wheels 26a, 26b. Supported by. In this case, the rear wheels in the lower frames 28a, 28b that form the vehicle body frame 22
Pivot brackets 30a, 30b on the ends on the 26a, 26b side
Is installed. And these pivot brackets 30
Swing arms 34, which support the rear wheels 26a and 26b via axles 32, are mounted on the a and 30b shafts.

The swing arm 34 is constructed as shown in FIGS. 3 and 4. That is, the swing arm 34 includes a pair of arm members 36 and 38, two cross members 40 and 42,
It is basically composed of a support portion 44. Arm member 36, 38
Has a prismatic shape, and both ends thereof are tapered welded portions 46a,
46b and 48a, 48b. Further, the ends of the arm members 36 and 38 on the side of the welded portions 46b and 48b are welded portions 46c and 48c cut out in an arc shape.

Both ends of the cross member 40 are pivot brackets 30a, 30
This has a cross pipe 54 that is pivotally attached to b.
At both ends of 54, welded portions 56a and 56b joined to the welded portions 46a and 48a of the arm members 36 and 38 are formed to project.
The cross member 42 has a housing portion 58, and both side portions of the housing portion 58 are welded portions 60a and 60b extending to the cross member 40 side and joined to the welded portions 46b and 48b of the arm members 36 and 38. . Further, in the cross member 42, upper and lower end surfaces on the side of the support portion 44 are welded portions 62a and 62b joined to the support portion 44.

The support portion 44 has an axle insertion hole 64 and is formed in a substantially cylindrical shape. In this case, the axle insertion hole 64 is configured to have a variable diameter by a notch portion 66 that is notched along the axial direction. It should be noted that the notch 66 has a protrusion to which a bolt (not shown) is screwed.
68a to 68d are formed facing each other. Further, plate-shaped projecting pieces 70a and 70b are integrally formed on the outer peripheral portion of the support portion 44 so as to project toward the welded portions 62a and 62b of the cross member 42 and the ends of the arm members 36 and 38. .

The swing arm according to the present embodiment is basically configured as described above, and its operation and effect will be described next.

First, the case of assembling the swing arm 34 will be described.

Therefore, the welded portion 46, which is the front end portion of the arm members 36 and 38, is
The welded portions 56a and 56b of the cross member 40 are joined to a and 48a, respectively, and welded along the welding lines A and B shown in FIG. Next, the cross member 42 is fitted between the rear ends of the arm members 36 and 38, and the welded portions 46b and 48b of the arm members 36 and 38 are joined.
And the welded portions 60a and 60b of the cross member 42 are joined together and welded along weld lines C and D.

After the welding work of the arm members 36, 38 and the cross members 40, 42 is completed, the both ends of the support portion 44 are engaged with the arc-shaped welded portions 46c, 48c formed at the rear ends of the arm members 36, 38. To combine. In this case, the end portion of the cross member 42 on the bearing portion 44 side is fitted between the projecting pieces 70a, 70b protruding from the outer peripheral portion of the bearing portion 44 to the cross member 42 side. Further, the ends of the arm members 36 and 38 are also fitted between the projecting pieces 70a and 70b. Therefore, both ends of the bearing portion 44 and the welded portions 46c and 48c of the arm members 36 and 38 are welded along the welding lines E and F, and the bearing portion 44 is
Welding portions 62a, 62b of the projecting pieces 70a, 70b and the cross member 42
And are welded along welding lines G and H.

As described above, the assembly work of the swing arm 34 is completed. In this case, the swing arm 34 includes the arm members 36, 38,
The cross members 40, 42 and the bearing portion 44 are main constituent members, and the projecting pieces 70a, 70b as reinforcing members are formed integrally with the bearing portion 44. Therefore, unlike the prior art shown in FIG. 1, it is not necessary to separately provide the reinforcing plates 16a to 16d, and the assembling work is greatly simplified. Moreover, since the protrusions 70a and 70b are integrally formed,
The rigidity of the swing arm 34 will be further improved. Further, there is an advantage that the number of constituent members is reduced and the cost is reduced.

Next, the swing arm 34 for which the assembling work is completed is assembled to the vehicle body frame 22 shown in FIG. That is, both ends of the cross pipe 54 that constitutes the cross member 40 are pivot brackets 30a of the lower frames 28a, 28b,
The axle 32 is attached to the shaft 30b, and the axle 32 is inserted into the axle insertion hole 64 of the support portion 44 through a bearing or the like. The rear wheels 26a and 26b are attached to both ends of the axle 32. In this case, when the small four-wheeled vehicle 20 travels, the swing arm 34 swings around the cross pipe 54 to appropriately dampen vibrations received from the road surface.

[Advantages of the Invention] As described above, according to the present invention, a cross member is bridged between the rear ends of a pair of arm members whose front ends are pivotally attached to the vehicle body frame, and the cross members are provided on both sides of the cross member. While joining the long welded part along each arm member,
A pair of projecting pieces is provided along the axis of a support portion that supports the axle of the rear wheel, and the rear end portions of the pair of arm members and the cross member are sandwiched and joined by the pair of projecting pieces.

In this case, since the projecting piece is formed integrally with the support portion, the number of members forming the swing arm is reduced.
Also, by integrally forming the support portion and the protrusion,
Work such as positioning of the projecting pieces at the time of assembling the swing arm is also unnecessary. Therefore, the time required for assembling the swing arm can be shortened, so that the inexpensive swing arm can be provided. Further, the arm member and the cross member are joined together via a welding portion extending along the arm member, and the end portion of the arm member and the cross member are sandwiched by a pair of projecting pieces of the support portion. Since the members are joined in a closed state, the respective members that form the swing arm are firmly connected, and as a result, sufficient rigidity against external force can be obtained.

Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to this embodiment.
It goes without saying that various improvements and design changes can be made without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a perspective view of the structure of a swing arm according to the prior art, FIG. 2 is a structure explanatory view of a small four-wheeled vehicle equipped with a swing arm according to the present invention, and FIG. 3 is an exploded view of a swing arm according to the present invention. FIG. 4 is a structural perspective view showing an assembled state of the swing arm according to the present invention. 20 ... Small four-wheel vehicle 22 ... Body frame 24a, 24b ... Front wheels 26a, 26b ... Rear wheels 30a, 30b ... Pivot bracket 34 ... Swing arm 36, 38 ... Arm members 40, 42 ... Cross member 44 ... Bearings 70a, 70b … Protrusions

Claims (1)

[Scope of utility model registration request] 1. A swing arm for supporting a rear wheel of a vehicle having two rear wheels, a front end of which is pivotally attached to a body frame, and a pair of arm members which are swingable, and which extend along the arm member. A cross member bridged between the rear ends of the arm members and welded to the arm members on both sides, extending in the vehicle width direction of the vehicle, A swing arm, comprising: a pair of projecting pieces that are welded while sandwiching both the end portion and the cross member, and a supporting portion that supports the axle of the rear wheel.