JPH0240555B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frame structure for a straddle-type four-wheeled vehicle.

The frame has the role of holding the engine, power transmission device, passengers, luggage equipment, equipment, etc., and is the core structure of the vehicle that connects the front and rear wheels via the steering and suspension mechanism. be. Therefore, the frame must have sufficient strength and rigidity, be as compact as possible, and have a structure suitable for mass production. For this reason, a double cradle type frame or a semi-double cradle type frame is widely used as a basic frame structure in two-wheeled vehicles.

By the way, tricycles are used for traveling on rough terrain because they are more stable than two-wheeled vehicles when a driver rides on the vehicle. However, when making a sharp turn, the stability of the vehicle body deteriorates as the driver's weight shifts.

Therefore, we developed a prior art technology (Japanese Utility Model Application Publication No. 73694/1983) that converts the front wheels of a tricycle into two wheels to create a four-wheeled vehicle. However, in such prior art, only four wheels are provided on the frame of the two-wheeled vehicle, so the width of the front wheel is insufficient and the space for mounting the engine is narrow, resulting in the steps protruding outside the wheels. I was getting used to it. Therefore, there is a risk that stones, bushes, etc. may come into contact with the feet when driving on rough terrain. Further, since a large load is applied to the steering head portion, a strong material must be used for the head pipe portion, which inevitably results in a large weight.

The present invention was made in view of the above circumstances, and
The purpose of the present invention is to provide a frame structure for a straddle-type four-wheeled vehicle that is compact and has excellent strength, allowing easy inspection of the engine and other equipment.

Its features include: the front and rear of the frame;
It has two front wheels and two rear wheels each equipped with balloon tires, and a seat is placed toward the rear of the vehicle from the rear of the steering head, which rotatably supports the steering shaft relative to the frame, and is mounted on the upper end of the steering shaft. In addition to steering the front two wheels with a supported bar handle, steps are placed on the left and right sides of the vehicle between the front and rear wheels, allowing the vehicle to drive over rough terrain by steering the bar handle and driving the wheels with the engine mounted between the front and rear wheels. A straddle-type four-wheeled vehicle, in which the frames each include a pair of upper frames and a lower frame, and a plurality of spacer frames connecting the upper frame and the lower frame, and connecting the upper frame and the lower frame. The engine mounting part and the fuel tank mounting part are provided in a space that constitutes a framework and is surrounded by the upper frame, the lower frame, and the spacer frame, and a front cover is attached to the front side of the upper frame, and a rear cover is attached to the rear side of the upper frame. With,
In order to arrange a sheet on the top surface of the rear cover,
This is because mounting parts corresponding to the mounting parts of the front cover, rear cover, and seat are provided on the frame side.

Hereinafter, the present invention will be explained in detail with reference to embodiments of the drawings.

FIG. 1 is a perspective view showing a straddle-type four-wheel vehicle to which the frame structure of the present invention is applied, FIGS. 2 to 4 show the frame structure of the present invention, FIG. 2 is a perspective view, and FIG. The plan view and FIG. 4 are side views.

Fig. 1 shows a straddle-type four-wheeled vehicle 1, which has two front wheels 3 and two rear wheels 4 each mounted on a frame 2 shown in Fig. 2. Tires with a wide contact surface, so-called balloon tires 5, are installed. A bar handle 6 is used as the handle for operating the steering mechanism (described later) for the front wheels 3, and a bar step 7 is used as the step on which the driver's feet are placed. Reference numerals 8 and 9 denote a front cover and a rear cover that are placed over the frame 2, and a seat 10 is placed on the rear cover 9.

The structure of the frame 2 will be explained with reference to FIGS. 2 to 4. The frame 2 includes a pair of upper frames 11 ₁ , 11 ₂ and lower frames 12 ₁ , 12 ₂ , and a pair of upper frames 11 ₁ , 1 .
1 ₂ and a plurality of spacer frames 13 that keep the lower frames 12 ₁ and 12 ₂ at a predetermined distance. The upper frames 11 ₁ , 11 ₂ have tip portions 111 of a certain length bent forward, diagonally downward, and at angles away from each other, and the bent portions 112
A sloped portion 11 that slopes downward at a gentle angle toward the rear.
3 is formed to a certain length, and the rear end portion 114 behind the inclined portion 113 is bent horizontally or slightly upward. The tips of the upper frames 11 ₁ and 11 ₂ are connected by welding or the like to the axle 14 that supports the front wheels 3, and the spacer frame 131 and the front cover 8 are screwed between the tips 111. A U-shaped fixing frame 15 having screw holes 15a for this purpose is attached. The bent portion 112 is provided with a steering head 17 that supports the steering shaft 16 of the bar handle 6. The inclined part 113
is provided with a protruding piece 18 having a screw hole 18a for screwing the front cover 8, and a protruding piece 19 having a screw hole 19a for fixing the engine. Further, the rear end portion 114 is provided with a spacer frame 132 for keeping the upper frames 11 ₁ and 11 ₂ at a constant distance, and a projecting piece 21 having a screw hole 21a for fixing the handle 20.

On the other hand, the lower frames 12 ₁ and 12 ₂ are arranged approximately horizontally at equal intervals, and their tips are connected to the axle 14, and the rear end 1
21, stand it up, and attach the upper frame 11 ₁ ,
11 ₂ is connected to the rear end 114 of the rear end. In the middle of the horizontal part 122 of the lower frames 12 ₁ and 12 ₂ ,
Step bar 22 supporting the bar step 7
is mounted, and spacer frames 133 and 134 are provided at the rear thereof. A support portion 24 that supports the drive shaft 23 of the rear wheel 4 is provided at the bent portion 123 of the lower frames 12 ₁ , 12 ₂ . The tip portions 111 of the upper frames 11 ₁ and 11 ₂ and the horizontal portions 1 of the lower frames 12 ₁ and 12 ₂
22 and between the spacer frames 132 and 133, a reinforcing frame 27 is provided with protruding pieces 25 and 26 having screw holes 25a and 26a.
1,272 are provided. As a result, the upper frames 11 ₁ , 11 ₂ and the lower frame 12
₁ and 12 ₂ , a space A is formed in which an engine 28, a fuel tank 29, and other equipment are mounted. The engine 28 has the protruding pieces 19, 2
5 and 26 with screws 30.

The lower end of the steering shaft 16 is rotatably supported by a support part 31 provided at the center of the axle 14, and is supported by an arm 32 provided at the lower end of the wheel 14 and an arm 32 provided at the front wheel side. The front wheels 3 are steered by linking them to an arm 33 via a link mechanism 34. The front wheels 3 are mounted on U-shaped frames 35 provided at both ends of the axle 14 via king pins 36 so as to be steerable.

The front cover 8 has a front fender 801 integrally molded therein, and an air intake port 802 on the front surface of the cover between the front fenders 801.
and a screw hole 8a. Further, the rear surface of the front cover 8 is open, and protruding molds 803 having screw holes 8b are provided on both side edges thereof. On the other hand, the rear cover 9 has a rear fender 901 integrally molded therein, and has an open top surface so that the engine 28 and other equipment can be inspected. This rear cover 9 is provided with a plurality of screw holes (not shown) for screwing to the spacer frames 132 of the upper frames 11 ₁ and 11 ₂ . The upper surface openings of the front cover 8 and the rear cover 9 are blocked from placing the seat 10 thereon.

The arrangement of each main equipment with respect to the frame 2 is as follows.

A steering shaft 16 to which a bar handle 6 is attached is rotatably supported by a steering head 17 and a support portion 31 of an axle 14. and,
Upper frames 11 ₁ , 11 ₂ and lower frames 12 ₁ ,
An engine 28 is mounted in the space A of 12 ₂ , a fuel tank 29 is mounted at the rear of the engine 28, and an oil tank (not shown) is mounted at the side thereof. Next, the front wheel 3 is attached to the frame 35 at both ends of the axle 14 via a king pin 36, and the front wheel 3 and the steering shaft 16 are connected via a link mechanism 34. At the same time, a drive shaft 23 is attached to the support portion 24 on the rear wheel side, and the rear wheels 4 are attached to both sides of this drive shaft 23. And the upper frame 11 ₁ ,1
1 ₂ from the front, the rear cover 9 from the rear of the upper frames 11 ₁ , 11 ₂ , and the front cover 8 is attached to the fixing frame 15 and the protruding piece 1
8, and attach the rear cover 9 to the upper frame 1.
Screw it to the spacer frame 132 of 1 ₁ and 11 ₂ . Then, the seat 10 is placed on top of the rear cover 9.

As a result, a straddle-type four-wheel vehicle can be assembled with a lightweight and compact frame structure.

As described above, according to the frame structure of the straddle-type four-wheeled vehicle of the present invention, since the upper frame, the lower frame, and the spacer frame form a space, it is possible to accommodate heavy engines or large tanks. type can be easily installed by placing it in the space inside the frame from the side. Furthermore, although the front cover and rear cover are large, they are light and can be assembled by covering the frame from above. Furthermore, since the seat is disposed on the top surface of the rear cover, by fixing the seat, the center portion of the rear cover can be fixed, and by removing the seat, the engine and other components can be inspected from above.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a straddle-type four-wheel vehicle to which the frame structure of the present invention is applied, FIGS. 2 to 4 show the frame structure of the present invention, and FIG. 2 is a perspective view,
FIG. 3 is a plan view, and FIG. 4 is a side view. DESCRIPTION OF SYMBOLS 1...Saddle-type four-wheel vehicle, 2...Frame, 3...Front wheel, 4...Rear wheel, 5...Balloon tire, 6...Bar handle, 7...Bar step, 8...Front cover, 9...Rear cover, 10...Seat, 11 ₁ ,1
1 ₂ ... Upper frame, 12 ₁ , 12 ₂ ... Lower frame, 13, 131, 132, 133, 134 ... Spacer frame, 14 ... Axle, 16 ... Steering shaft, 17 ... Steering head, 23
... Drive shaft, 24 ... Support part, 28 ... Engine, 29
...Fuel tank, 34...Link mechanism.

Claims (1)

[Scope of Claims] 1. Two front wheels and two rear wheels each equipped with balloon tires are provided at the front and rear of the frame, and from the rear of the steering head part, which rotatably supports the steering shaft to the frame, to the rear of the vehicle body. Place the seat facing toward It is a straddle-type four-wheeled vehicle that uses a mounted engine to drive the wheels to travel on rough terrain, and the above-mentioned frames are each made up of a pair of upper and lower frames, a space between these upper and lower frames, and an upper frame. and a plurality of spacer frames that connect the lower frames, and the engine mounting part and the fuel tank mounting part are provided in a space surrounded by the upper frame, the lower frame, and the spacer frame, and A front cover is attached to the front side of the upper frame, a rear cover is attached to the rear side of the upper frame, and a seat is arranged on the upper surface of the rear cover.
A frame structure for a straddle-type four-wheeled vehicle, characterized in that mounting parts corresponding to the mounting parts of a rear cover and a seat are configured on the frame side. 2 Attach a U-shaped fixing frame for supporting the front cover to the tip of the upper frame, and attach a mounting part for attaching the front cover that covers the front of the vehicle to the tip of the fixing frame and the upper frame. and a mounting part for mounting a rear cover covering the rear of the vehicle body on the rear end of the upper frame or the spacer frame, and a mounting part for mounting a seat on the upper surface of the center part of the rear cover. A frame structure for a straddle-type four-wheeled vehicle according to claim 1.