JPH0115437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rear wheel support device suitable for use in a vehicle equipped with two rear wheels, such as a tricycle that travels on rough terrain.

A three-wheeled vehicle equipped with balloon tires for traveling on rough terrain has been proposed and put into practical use, and since the tires themselves have a large cushioning performance, this type of vehicle generally uses a rigid suspension system.

However, in view of requirements such as ride comfort and running performance, it is preferable that the suspension system be of a shock-absorbing type. It is conceivable to construct a suspension system by interposing a unit, but when the rear wheel receives an impact from uneven ground, this impact acts as a force that twists the swing arm via the rear axle.
The strength of the swing arm, especially against the above-mentioned torsion,
Stiffness needs to be considered.

In addition, for vehicles with two rear wheels of this type, the width between the two rear wheels is limited because it constitutes the actual width of the vehicle body, and since the two rear wheels are equipped with balloon tires, the tires are large, so the width between the two rear wheels is limited. When driving two wheels, it is necessary to rationally arrange the driving force transmission means such as a sprocket and a brake device to transmit the driving force from the engine within the limited space between the rear two wheels. In addition to installing the cushion unit, it is desirable to make the shock absorbing suspension structure for the rear two wheels simple and rational while effectively arranging these devices.

The present inventors have devised the present invention in order to solve the above-mentioned problems in vehicles having two rear wheels such as this type of tricycle.

An object of the present invention is to improve the torsional strength and rigidity of the swing arm in a vehicle equipped with two rear wheels as described above, and to employ a shock absorbing suspension structure for the two rear wheels. To provide a rear wheel support device for a vehicle that rationally arranges a driving force transmission means and a brake device in a limited space and realizes simple and rational support for the rear two wheels that is favorable in terms of strength and rigidity. It's there.

In order to solve the above problems and achieve the object, the present invention has a front end of a swing arm pivoted to the rear part of the frame where the engine is disposed so as to be able to swing vertically, and a rear action unit installed between the frame and the swing arm. In a vehicle in which a single rear axle is rotatably supported at the rear end of the swing arm, and two rear wheels are attached to both left and right ends of the rear axle, the swing arm has a front end at the rear of the frame. A cylindrical axle support member is horizontally joined between the rear ends of a pair of left and right members spaced apart on both sides, and the rear axle is rotatable through bearings at both left and right ends within the axle support member. At the same time, the left and right members of the swing arm are formed in a symmetrical shape in which the gap between the front ends is gradually wider than the gap between the rear ends, and the frame of the swing arm is wider than the axial length of the axle support member. It is characterized by a large attachment interval between the left and right front end portions of the members relative to the rear portion.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. This will reveal further objects and advantages of the invention.

FIG. 1 is a schematic external perspective view of the tricycle, FIG. 2 is a perspective external view of the frame, and FIG. 3 is a perspective external view showing only the frame.

Figures 2 and 3 are diagrams that allow the frame 1 to be clearly understood.The frame 1 has a vertical head tube 2 at its front end, and a main frame member made of pipe material extending rearward from the upper rear surface of the head tube 2. 3. That is, a so-called backbone pipe is extended. A cross member 4 is suspended horizontally at the rear end of this member 3, and the cross member 4 is joined to the rear end of the member 3 at the center. Head tube 2
In the illustrated example, two down tubes 5, 5 extend diagonally downward and rearward, and diagonally upward and rearward in the illustrated example. The illustrated example shows a double cradle type frame. A sub-cross member 6 is installed between the front parts of the down tubes 5, 5, a similar member 7 is installed between the lower rear parts, and a reinforcing member 8 is installed between the front parts of the members 6 and 3.
5 is attached with an engine support bracket 9.

Head tube 2 has upper and lower bridges 19, 2.
The steering shaft 21a supported at Lower members 22b, such as bottom cases fitted to 22a, 22a, Axle 23 of a single front wheel 23 with a balloon tire mounted between the lower ends of 22b
I support a.

Therefore, the front wheels 23 are supported by a shock absorbing suspension, and the reaction force exerted on the front wheels 23 from the road surface is buffered in the same manner as in a two-wheeled vehicle, and the load thereof is transmitted to the main frame member 3 via the head tube 2.

On the other hand, an engine 29 is mounted between the down tubes 5, 5 and the main frame member 3, a handle 33 is mounted on the top bridge 19, a headlight 34 is mounted in front of the handle 33, and a headlight 34 is mounted on the front of the main frame member 3. A fuel tank 35 is disposed behind the fuel tank 35, and a seat 36 is disposed behind the fuel tank 35. Reference numeral 27 indicates a front fender, and numeral 28 indicates a rear fender.

Brackets 10, 10 are attached to the rear lower portions of the down tubes 5, 5 which are bent into an L shape, and the front ends of the left and right members 12, 12 constituting the swing arm 11 are connected to the shaft 12a and the collar. 12b, members 12, 12
An axle support member 13 for the rear axle is horizontally joined and integrated between the rear ends.

FIG. 4 is a plan view of the rear wheel suspension support section, in which one axle 18 is inserted through the axle support member 13,
The axle 18 is rotatably supported via bearings (not shown) interposed on both sides of the inner diameter part of the axle support member 13, and supports rear wheels 17, 17 equipped with balloon tires at both ends of the axle 18. As shown in the figure, the swing arm 11 has left and right members 12,
12 is formed in a bilaterally symmetrical shape in which the distance between the front ends is gradually wider than the distance between the rear ends, and a transverse joint is formed between the narrowest rear ends of both members 12, 12. cylindrical axle support member 13
is formed such that its axial length l is smaller than the mounting interval L between the front end portions of the left and right members 12, 12 of the swing arm 11 relative to the rear portion of the frame 1.
That is, the relationship l<L is satisfied.

On the other hand, a bifurcated bracket 14 is fixed at the center of the cross member 4 at the rear end of the main frame member 3, that is, at the rear of the member 3, and the members 12, 12 of the axle support member 13 at the rear end of the swing arm 11 are fixed. A bifurcated bracket 15 is fixedly installed in front of the central part between the two, and as shown in FIG. Each is pivotally connected, and the suspension is supported by a rear action unit 16. Thus, the swing arm 1 is moved at the rear of the main frame member 3 by the single rear action unit 16.
The center of one axle support member 13 is suspended and supported.

A sprocket 24 as a driving force transmitting means is fixedly installed in a portion of one of the left and right extending portions 18a and 18b of the axle support member 13 of the axle 18 near the axle support member 13, and the sprocket 24 is connected to the engine 29 side. is connected to the drive sprocket of 18b via a chain, and the axle support member 1 of the other
3 is a brake device, in this embodiment a disc brake device is adopted, so the brake disk 25 that is a rotating member of this is fixedly installed, and the brake disk 25 is a caliper that is a fixed member that is fixedly installed on the axle support member 13. 26, which allows for a rational arrangement of drive and braking mechanisms.

In the above, the reaction force from the road surface to the rear wheel 17 is transmitted to the axle support member 13 and the swing arm 11, the swing arm 11 swings about the front end as a fulcrum, and is transmitted to the rear action unit 16.
This vibration is absorbed and buffered by the unit 16.
In the embodiment, the load on the unit 16 is transmitted to the main frame member 3 via the member 4, and since one end of the unit 16 is connected to the center of the member 4, the load on the unit 16 is transmitted in the axial direction of the main frame member 3. That is, this load is transmitted in the axial direction of the back ball type, and this load is received by the frame member 3, which is the thickest, base body, and has high strength and rigidity, and is also transmitted to the front wheel 23, which is transmitted to this frame member 3 as described above. The load due to the reaction force from the road surface interferes with and cancels out each other on member 3, and the effect on other members is suppressed as much as possible, and the diameters of other members can be reduced accordingly. .
Since it is supported on the axis of the main frame member 3 and the rear action unit is supported at the center of the axle support member 13 of the swing arm, load support is also reasonable, and only one rear action unit is required. That is, the number of parts can be kept to a minimum, and the number of unit support brackets can also be kept to a minimum.

The swing arm 11 includes left and right members 12, 12 formed in a symmetrical shape in which the distance between the front ends is gradually wider than the distance between the rear ends;
It is composed of a cylindrical axle support member 13 that is horizontally joined between the narrowest rear ends of both members 12, 12, thereby forming a flat concave closed structure with the rear end closed. Moreover, as is clear from the relationship l<L, the swing is longer than the axial length l of the axle support member 13, which has bearings interposed at both left and right ends to rotatably support the axle 18 of the two rear wheels. Since the attachment interval L between the front ends of the left and right members 12, 12 to the rear of the frame 1 of the arm 11 is larger, twisting of the swing arm due to reaction force from the road surface to the rear wheels 17, 17 is possible. Therefore, the strength and rigidity of the swing arm 11 that supports the rear two wheels is obtained, and the reaction force from the road surface is prevented.
It is possible to sufficiently support the reaction force of the reaction unit, and to maintain sufficient strength and rigidity for practical use while reducing the material thickness and weight of the swing arm 11. In addition, the axle support member 13 is installed between the rear ends of the left and right members 12, 12, and the rear action unit is connected to this, and it is possible to connect and support the unit at the center of the vehicle body. A rational shock absorbing suspension system can be realized using the cushion unit.

In addition, since the axial length l of the axle support member 13 is made smaller than the mounting interval L of the swing arm 11 at the rear of the frame 1, the left and right rear wheels 17,1
A large space can be ensured between 7 and the axle support member 13. Therefore, by effectively utilizing the space on both sides of the axle support member 13, as in the embodiment, a brake disc of a brake device is mounted on one shaft portion 18b of the rear axle 18 that protrudes from the axle support member 13 on both the left and right sides. 25, the sprocket 24 of the driving force transmission means from the engine 29 can be rationally arranged on the other shaft portion 18a, and the tread of the left and right rear wheels 17, 17 can be reduced while reducing the It becomes possible to easily mount wide tires such as balloon tires for terrain driving.

By the way, in the embodiment, the reaction unit 1
6 is supported in front of the axle support member 13, that is, in front of the rear axle. According to this, the stroke of the unit 16 consisting of a hydraulic shock absorber when the shock absorber is activated is smaller than the stroke of the axle.
The sliding amount of the piston, cylinder, etc. inside the unit is small, suppressing heat generation, etc., and therefore there is little change in damping force characteristics even when driving on rough roads for a long time.
Riding comfort etc. can be made constant and stable. Further, since the rear action unit 16 is arranged on the center line of the vehicle body, twisting thereof can be suppressed as much as possible, and reliable, stable and durable operation can be improved.

In the above embodiment, the front ends of the left and right members 12, 12 forming the swing arm 11 are coaxially supported by individual shafts, but it is possible to horizontally extend a common shaft between the rear parts of the frame and thereby support the front ends of the members. This allows the swing arm to have a mouth-shaped closed structure with the front end and rear end closed.

FIG. 5 shows a specific example of the swing arm portion, showing the left and right members 11 of the swing arm 111.
Collars 112b, 112b are provided at the front ends of the collars 2, 112, and are pivotally connected to brackets 110, 110 on the vehicle body frame side via a support shaft 112a. member 11
A cross member 111a made of a press-formed steel plate or the like is horizontally joined between the members 112, 112, and the cross member 111a is provided from the front to the rear of the members 112, 112. left and right members 112,
An axle support member 113 made of a pipe material is horizontally joined to the rear end of the axle support member 112, and brackets 115, 115 are attached so as to extend over a part of the front outer periphery of the member 113 and a part of the inner rear parts of the left and right members 112, 112. is fixedly installed, one end of the above-mentioned rear action unit is exposed between them, and the swing arm 111 and one end of the unit are connected via brackets 115, 115.

The swing arm 111 has a mounting interval L to the vehicle body frame set to be larger than the axial length l of the axle support member 113 forming the rear part of the swing arm 111. An axle 118 is inserted through the axle 118, and the axle 118 has bearings 113a, which are interposed on both sides of the inner diameter part of the axle support member 113.
The swing arm 111 is rotatably supported via the bearing 113a, so that the mounting distance L between the swing arm 111 and the vehicle body frame is larger than the distance L' between the two bearings 113a, 113a.

The aforementioned rear wheels are supported at both ends of the portions 118a and 118b extending from the axle support member 113 of the axle 118, and a sprocket 124 serving as a driving force transmitting means is mounted on one of the extending portions 118a in the circumferential direction. The sprocket 124 was fixed to the axle supporting member 113, and the sprocket 124 was placed close to one end of the axle support member 113 in order to cope with the bending caused by the chain drive to the axle 118.

On the other extending portion 118b of the axle 118, a brake device, in the illustrated example, a drum type brake device 127, is attached close to the end of the axle support member 113, and a brake drum 12, which is a rotating member, is attached to the axle 118 side.
5, the side wall 128 of the housing, which is a fixed member, is attached to the axle support member 11 so that the axle 118 can rotate freely.
A brake shoe 126 is fixed to the housing 128a, and a lever 126b is fixed to the extending portion of the pin 126a, and is connected to a brake cable (not shown) or the like.

In the above, the reaction force from the road surface to the rear wheels is transmitted to the swing arm 111 via the axle 118, the bearings 113a, 113a, and the axle support member 113, but as described above, the swing arm 111 swings more than the distance l' between the bearings 113a, 113a. Since the attachment interval L of the arm 111 to the vehicle body frame is increased, twisting of the swing arm 111 due to the load accompanying the reaction force can be prevented as much as possible, and the length l of the axle support member 113 is Since the mounting interval L to the vehicle body frame can be shortened, the space between the axle support member 113 and the rear wheel can be effectively secured, and this space can be used to transmit driving force to both sides of the axle support member 113. The sprocket 124 and the brake device as means can be arranged rationally.

In the example shown above, the frame is of a double cradle type, but the cross member between the front and rear parts of the down tubes 5, 5 described above is removed, the engine is interposed between them, and the engine is integrated into the frame. Of course, a diamond-shaped frame can also be used as a part, and although the frame and swing arm are made of pipe material in the illustrated example, a steel plate-shaped frame can also be adopted.

As described above, according to the present invention, a rear axle having two rear wheels attached to both left and right ends is provided between the rear ends of the left and right members that are spaced apart on both sides of the pair of left and right members that constitute the swing arm. By horizontally joining the cylindrical axle support member that is rotatably supported through the bearing, the swing arm has a closed structure at the rear end due to the cylindrical axle support member, and the left and right members of the swing arm are It is formed in a symmetrical shape in which the distance between the front ends is gradually wider than the distance between the rear ends, and the mounting distance between the front ends of the left and right members relative to the rear of the swing arm frame is larger than the axial length of the axle support member. As a result, the strength and rigidity of the swing arm can be increased, and in particular, twisting of the swing arm due to reaction force from the road surface to the left and right rear wheels can be prevented as much as possible.

In addition, the axial length of the axle support member is smaller than the mounting interval of the swing arm at the rear of the frame, and a large space is secured between the left and right rear wheels and the axle support member, so that The brake system and drive force transmission means can be separated and rationally placed on the left and right sides of the rear wheels by making effective use of the space, and the tread of the left and right rear wheels can be reduced while providing balloon tires for running on rough terrain. This makes it possible to easily install wide tires such as .

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a schematic perspective view of the external appearance of a tricycle, Fig. 2 is a perspective view of the frame, Fig. 3 is a detailed perspective view of the frame, and Fig. 4 is a perspective view of the tricycle.
The figure is a plan view of the rear wheel suspension support section, and FIG. 5 is a cutaway plan view of a specific embodiment. In the drawing, 1 is a vehicle body frame, 11, 111 is a swing arm, 13, 113 is an axle support member, 1
6 is the rear action unit, 17 is the rear wheel, 1
8, 118 are axles, 24, 124 are sprockets, 25, 26 and 127 are brake devices, 11
3a is a bearing.

Claims (1)

[Scope of Claims] 1. A swing arm is pivotally connected at its front end to the rear of the frame where the engine is disposed, so that it can swing vertically, a rear action unit is interposed between the frame and the swing arm, and the rear end of the swing arm is In a vehicle that has one rear axle rotatably supported on the rear axle, and two rear wheels attached to both left and right ends of the rear axle, the swing arm is attached to the left and right sides of the pair with the front end pivoted to the rear of the frame. A cylindrical axle support member is horizontally joined between the rear ends of the separated members, and the rear axle is rotatably supported within the axle support member via bearings at both left and right ends, and the left and right sides of the swing arm are The front ends of the left and right members are formed in a symmetrical shape in which the distance between the front ends is gradually wider than the distance between the rear ends, and the front ends of the left and right members are attached to the rear of the swing arm frame longer than the axial length of the axle support member. A rear wheel support device for a vehicle characterized by a large gap. 2. In claim 1, a brake device is provided on one shaft portion of the rear axle that protrudes from the axle support member to both left and right sides, and a means for transmitting driving force from the engine is provided on the other shaft portion. A rear wheel support device for a vehicle, characterized in that: 3. In claim 2, the braking device includes a fixed member supported at one end of the axle support member and a rotating member attached to the rear axle, and the driving force transmission member is a sprocket. A rear wheel support device for a vehicle, characterized by: