JPH0742952Y2 - Rear cushion unit mounting structure for rear two-wheel vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial field of application) The present invention relates to a rear two-wheel vehicle such as a straddle-type four-wheel vehicle, and particularly to a weight reduction of a vehicle body frame at a rear cushion unit mounting portion, After increasing rigidity and increasing economic efficiency, 2
The present invention relates to a rear cushion unit mounting structure for a wheeled vehicle.

(Prior Art) Generally, a straddle-type four-wheel vehicle has a pair of left and right front wheels steered by a bar handle and a pair of left and right rear wheels driven by an engine mounted in the lower center of the vehicle body, A rider straddling the seat on the rear upper part operates by manipulating a rod handle.

In a straddle-type four-wheel vehicle, as shown in FIGS. 4 and 5, a pair of left and right seat rails 1 are arranged in the vehicle front-rear direction, and seats (not shown) are attached above these seat rails 1. Both seat rails 1 are connected and coupled by a bridge tube 2. In the bridge tube 2, two pressed parts are welded together to form a middle-fitting structure. Reinforcement 3 reinforces each connecting portion between bridge tube 2 and seat rail 1. The rear cushion mounting bracket 4 is fixed to the rear side of the bridge tube 2. Further, each of the seat rails 1 is supported by a pair of left and right seat pillars 5 extending from below.

(Problems to be solved by the invention) Such a conventional rear cushion unit mounting structure has the following problems. That is, the bridge tube 2
Since the two pressed parts are combined to form a middle-matching structure by welding, the number of welded parts increases, the processing cost of the bridge tube 2 increases, and the production cost increases.

Further, since there is one bridge tube 2 and the rear cushion mounting bracket 4 is fixed to one side (rear side) of this bridge tube 2, the load from the rear wheel (not shown) is applied to the bridge tube 2 by a torsion load and a bending load. This load acts locally on the joint between the bridge tube 2 and the seat rail 1.

For this reason, it has been necessary to increase the pipe size at the joint between the seat rail 1 and the bridge tube 2 to increase the strength, and to attach a reinforcement member such as the reinforcement 3 near the joint. Therefore, the weight of the entire body frame is increased, and the workability in the production process is not preferable.

Further, as shown in FIG. 4, the left and right seat pillars 5 are curved upward in the middle, and the bridge tube 2 is provided at the connecting portion between the rear end portion of the seat pillar 5 and the seat rail 1 so that The load applied can be released to the seat pillar 5 to reduce the load on the seat rail 1. In this case, however, the latter half of the seat rail 1 is not supported by the seat pillar 5 and extends rearward in a cantilevered manner. The rear portion of the seat rail 1 may lack rigidity with respect to the weight of the rider and the weight of luggage loaded on the rear carrier.

The present invention has been made in consideration of the above circumstances, and it is possible to reduce the production cost as well as to reduce the weight of the vehicle body frame while ensuring the rigidity around the rear cushion unit mounting portion and the rear portion of the vehicle body frame. It is another object of the present invention to provide a rear cushion unit mounting structure for a rear two-wheel vehicle that can further improve workability.

[Constitution of device]

(Means for Solving the Problem) In order to achieve the above object, a rear cushion unit mounting structure for a rear two-wheel vehicle according to the present invention has a pair of left and right seats extending from an upper portion of a body tube connected to a main tube to a rear side of a vehicle body. While extending the rail, extend a pair of left and right seat pillars diagonally upward and rearward from the bottom of the body tube,
The rear end of this seat pillar is connected to the rear end of the seat rail, and the middle part of the left and right seat rails and the middle part of the left and right seat pillars are connected by a pair of left and right connecting tubes. The front and rear bridge tubes are connected to each other with a pair of front and rear bridge tubes extending in the left-right direction, and the strength of the front bridge tube is higher than that of the rear bridge tube. The rear cushion mounting bracket is fixed between both bridge tubes while adjusting to the position.

(Operation) In this way, when the left and right seat rails are connected by a pair of front and rear bridge tubes and the rear cushion mounting bracket is fixed between the front and rear bridge tubes, the rear wheel load from the rear cushion unit is Is evenly distributed to the left and right seat rails via the bridge tube, and the load is prevented from locally concentrating on the seat rail. Further, the torsion load does not act on the bridge tube.

Therefore, it is not necessary to increase the pipe size or to provide a reinforcement such as a reinforcement in the joint portion of the seat rail and the bridge tube, and it is possible to reduce the weight of the vehicle body frame while ensuring the rigidity, and to weld the welded portion. It is possible to reduce costs and improve workability by reducing

The load acting from the rear cushion unit is directed obliquely upward and upward, and more acts on the bridge tube on the front side. Since the strength of the front side bridge tube is higher than that of the rear side bridge tube, the rigidity of the front side bridge tube is sufficiently secured against such many loads. On the other hand, excessive strength of the rear bridge tube is removed, which leads to weight reduction of the vehicle body frame.

In addition, since the position of the front bridge tube where a large amount of load acts in this way is aligned with the connecting position of the seat rail and the connecting tube, the load acting on the front bridge tube passes through the connecting tube and the seat pillar. Is directly escaped to. Therefore, the load concentration on the seat rail is prevented more effectively. Since the rear end of the seat pillar is connected to the rear end of the seat rail, the rear end of the seat rail does not have a cantilever shape, and the rigidity of the rear portion of the vehicle body frame is ensured.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a side view showing a straddle-type four-wheel vehicle having an embodiment of a rear cushion unit mounting structure for a rear two-wheel vehicle according to the present invention. In FIG. 2, reference numeral 11 indicates a vehicle body frame, front wheels 12 are attached to the front of the vehicle body frame 11, and the front wheels 12 are steered by a rod handle 13. Rear wheels 14 are provided at the rear of the vehicle body frame 11, and the rear wheels 14 are rotationally driven by an engine 15 mounted in the center of the vehicle body. A seat 16 is attached to the upper rear of the body frame 11.

FIG. 1 is a perspective view showing a vehicle body frame having an embodiment of a rear cushion unit mounting structure for a rear two-wheel vehicle according to the present invention. The vehicle body frame 11 is formed by forming metal tubes into a desired shape for each part and connecting the metal tubes. Welding means are mainly used for the connection.

In FIG. 1, a main pipe 18 is provided in the upper center of the vehicle body, and a pair of left and right front tubes 19 extending obliquely forward and downward are connected to the front portion of the main pipe 18. A pair of left and right body tubes 20 extending downward are connected to the rear portion of the main pipe 18. The body tube 20 is curved below the vehicle body to form a pair of left and right lower tubes 21 extending forward of the vehicle body and connected to the front tube 19.

The front wheel 12 is supported by the front tube 19 and the lower tube 21 in front of the vehicle body frame 11. A steering plate 23 is fixed to the front tube 19 and the main tube 18, a head pipe (not shown) is attached to the steering plate 23, and a steering shaft (not shown) is fitted into the head pipe. A bar handle 13 is attached to the upper end of the steering shaft, and a front wheel 12 is connected to the lower end. An engine 15 is mounted in a space surrounded by the body tube 20 and the lower tube 21.

From the top of the body tube 20 a pair of left and right seat rails
24 extends backwards. On the other hand, a pair of left and right seat pillars 25 extend obliquely rearward and upward from the lower portion of the body tube 20, and the rear end portion of the seat pillar 25 is the seat rail.
It is connected to 24.

Further, the middle portion of the left and right seat rails 24 and the middle portion of the left and right seat pillars 25 are connected and reinforced by a pair of left and right connecting tubes 26. The rear end of the seat rail 24 is connected and coupled by the guide plate 27.

The left and right seat rails 24 are connected and fixed by a pair of front and rear bridge tubes 28A, 28B extending in the left-right direction. The position of the bridge tube 28A on the front side of the vehicle body is aligned with the connecting position of the seat rail 24 and the connecting tube 26. As the front and rear bridge tubes 28A and 28B, for example, circular pipes made of extruded material are used, but drawn materials may be used for the bridge tubes 28A and 28B, and the shapes thereof such as square pipes and plates are not limited.

A rear cushion mounting bracket 29 is fixed between the bridge tubes 28A and 28B. That is, the front end portion of the rear cushion mounting bracket 29 is fixed to the bridge tube 28A, the rear end portion is fixed to the bridge tube 28B, the load transmitted from the rear wheel 14 to the rear cushion mounting bracket 29 by these both bridge tubes 28A, 28B. Supported.

The mounting position of the rear cushion mounting bracket 29 may be the A position, the B position, or the C position shown in FIG. Reference numeral D indicates a hip point. In this case, a load acts on each of the mounting positions A, B, and C from the swing arm 30 via the rear cushion unit 31.

FIG. 3 is a diagram showing a relationship between loads acting on the respective mounting positions A, B, and C. The rider weight F ₁ acts from the hip point D of the seat 16, while the loads F ₂ , F ₃ , F ₄ from the rear cushion unit 31 act on the respective mounting positions A, B, C. In this case, the B position and the C position respectively include the B position and the C position.
The moments of F ₁ · l ₁ and F ₁ · l ₂ act around the position, which is disadvantageous in terms of strength of the seat rail 24. On the other hand, at the position A, since it is almost directly below the hip point D, no moment is generated, which is advantageous in terms of strength of the seat rail 24. Therefore, the rear cushion mounting bracket 29
Is attached to the A position substantially below the hip point D.

In this case, the direction of the load from the rear cushion unit 31 on the rear cushion mounting bracket 29 is directed diagonally upward and forward. Therefore, the loads acting on the pair of front and rear bridge tubes 28A and 28B supporting the rear cushion mounting bracket 29 are not equal, and the bridge tubes on the rear side of the vehicle body
A larger load is applied to the bridge tube 28A on the front side of the vehicle body than the 28B.

In this way, the bridge tube 28A on the front side of the vehicle body on which a large load acts is compared with the bridge tube 28B on the rear side.
For example, the strength is increased by forming a large diameter or a thick wall.

Thus, according to the above embodiment, the left and right seat rails 24
Connect between the front and rear with a pair of front and rear bridge tubes 28A, 28B,
Since the rear cushion mounting bracket 29 is fixed between the front and rear bridge tubes 28A and 28B, the load from the rear cushion unit 31 is applied to the front and rear bridge tubes 28A and 28B.
The load is evenly distributed to the left and right seat rails 24 via B, and the load is prevented from locally concentrating on the seat rails 24. Further, the torsion load does not act on the bridge tubes 28A and 28B.

Therefore, the seat rail 24 and the bridge tube 28A, 28
It is not necessary to increase the pipe size or to provide reinforcements such as lean reinforcement at the joint of B, so that it is possible to reduce the weight of the body frame 11 while ensuring rigidity and reduce the cost by reducing the welded portion. And workability can be improved.

The load acting from the rear cushion unit 31 is more exerted on the front side bridge tube 28A, and the front side bridge tube 28A is connected to the rear side bridge tube 28B.
In contrast, since the strength is increased, the rigidity of the bridge tube 28A on the front side is sufficiently secured. On the other hand, on the other hand, since the excessive strength of the rear bridge tube 28B is removed, it contributes to the weight reduction of the vehicle body frame 11.

Further, since the position of the front bridge tube 28A on which a large amount of load acts in this way is aligned with the connecting position between the seat rail 24 and the connecting tube 26, the load acting on the front bridge tube 28A is Connection tube 26
It is escaped directly to the seat pillar 25 via the. Therefore, the concentration of the load on the seat rail 24 is more effectively prevented. The rear end of the seat pillar 25 is the seat rail 24.
Since the rear end of the seat rail 24 is connected to the rear end of the vehicle body 11, the rear end of the seat rail 24 does not have a cantilever shape, which ensures the rear rigidity of the vehicle body frame 11.

Further, in this embodiment, since the mounting position of the rear cushion mounting bracket 29 is substantially right below the hip point D, an unnecessary moment does not act on the seat rail 24, and the strength of the seat rail 24 is kept sound. Can be improved.

Although a saddle-ride type four-wheel vehicle has been described in the above embodiment, the present invention is not limited to this, and the invention can be similarly applied to a saddle-ride type three-wheel vehicle.

[Effect of device]

A rear cushion unit mounting structure for a rear two-wheel vehicle according to the present invention extends a pair of left and right seat rails from an upper portion of a body tube connected to a main tube to a rear portion of a vehicle body, and extends diagonally rearward and upward from a lower portion of the body tube. Extend a pair of seat pillars, connect the rear end of this seat pillar to the rear end of the seat rail, and connect the middle part of the left and right seat rails and the middle part of the left and right seat pillars with a pair of left and right connecting tubes. In addition, the left and right seat rails are connected by a pair of front and rear bridge tubes that extend in the left-right direction, the strength of the front bridge tube is higher than that of the rear bridge tube, and the position of this front bridge tube is increased. Align it with the connecting position of the seat rail and connecting tube, and place the rear cushion between both bridge tubes. It is obtained by fixing the mounting bracket.

By doing this, the rear wheel load from the rear cushion unit is evenly distributed to the left and right seat rails via the front and rear bridge tubes, and it is possible to prevent the load from being locally concentrated on the seat rail, and at the same time, Since the torsion load does not act on the bridge tube, it is not necessary to increase the pipe size at the joint between the seat rail and the bridge tube, or to provide reinforcement materials such as lean reinforcement, thus ensuring rigidity while reducing the weight of the body frame. It is possible to reduce the number of welded portions and reduce costs and improve workability.

In addition, the strength of the front bridge tube where the load from the rear wheel acts more is higher than that of the rear bridge tube, so the rigidity of the front bridge tube is sufficiently secured, and the rear bridge tube is also secured. Excessive strength is eliminated, leading to a lighter body frame.

Further, since the position of the front bridge tube on which a large amount of load acts is aligned with the connecting position of the seat rail and the connecting tube, the load acting on the front bridge tube passes through the connecting tube and the seat pillar. Is directly escaped to. Therefore, the load concentration on the seat rail is prevented more effectively. Since the rear end of the seat pillar is connected to the rear end of the seat rail, the rear end of the seat rail does not have a cantilever shape, and the rigidity of the rear portion of the vehicle body frame is ensured.

[Brief description of drawings]

FIG. 1 is a perspective view showing a vehicle body frame having an embodiment of a rear cushion unit mounting structure for a rear two-wheel vehicle according to the present invention, and FIG. 2 is a saddle-ride type four-wheel vehicle having the above embodiment. 3 is a side view, FIG. 3 is a view showing a relationship of loads acting on the seat rail in the above-described embodiment, FIG. 4 is a perspective view showing a conventional rear cushion unit mounting structure, and FIG. 5 is VV in FIG. It is sectional drawing cut | disconnected and shown by a line. 18 …… Main tube, 20 …… Body tube, 24 ……
Seat rail, 25 …… Seat pillar, 26 …… Connecting tube, 28A, 28B …… Bridge tube, 29 …… Rear cushion mounting bracket.

Claims (1)

[Scope of utility model registration request] 1. A pair of left and right seat rails extends from the upper part of a body tube connected to a main tube to the rear of the vehicle body, and a pair of left and right seat pillars extends obliquely rearward and upward from the lower part of the body tube. While connecting the rear end to the rear end of the seat rail,
The middle part of the left and right seat rails and the middle part of the left and right seat pillars are connected by a pair of left and right connecting tubes, and the left and right seat rails are connected by a pair of front and rear bridge tubes extending in the left and right direction. Make the strength of the bridge tube stronger than that of the rear bridge tube, align the position of this front bridge tube with the connecting position of the seat rail and connecting tube, and fix the rear cushion mounting bracket between both bridge tubes. Rear cushion unit mounting structure for rear two-wheel vehicles.