JPH0240556B2 - - 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 two front wheels and two rear wheels each equipped with balloon tires at the front and rear of the frame, and from the rear of the steering head, which rotatably supports the steering shaft relative to the frame, towards the rear of the vehicle. A seat is placed on the vehicle, and the front two wheels are steered using a bar handle supported at the upper end of the steering shaft. Steps are placed on the left and right sides of the vehicle body between the front and rear wheels, and the wheels are driven by an engine mounted between the front and rear wheels. A straddle-type four-wheeled vehicle designed to travel on rough terrain, in which each of the frames is connected to a pair of upper and lower frames, between the upper and lower frames, and between the upper and lower frames. Consisting of a plurality of spacer frames, the upper frame is bent forward and diagonally downward, and the tip thereof is connected to the axle, and the upper frame is connected to the rear of the bent part and continues downward at a gentle angle for a predetermined length. The lower frame is comprised of a horizontal part whose tip is connected to the axle, and a rear end of the horizontal part. and a rear end part continuous to the bent part and connected to the rear end of the upper frame, and between the tip of the upper frame and the horizontal part of the lower frame. A reinforcing frame is provided diagonally across the spacer frame, and the middle part of the spacer frame is connected between the rear ends of the upper frame, and the middle part of the spacer frame is connected between the rear ends of the horizontal parts of the lower frame. A reinforcing frame is vertically connected between them, and an engine mounting part is provided on each of the inclined part of the upper frame and the reinforcing frame, and the inclined part of the upper frame and the lower part are connected through these mounting parts. An engine is mounted in a space surrounded by a horizontal part of the frame and a reinforcing frame, and a step bar supporting the steps at both ends is mounted on the horizontal part of the lower frame, facing the bottom surface of the engine.
This is because the left and right steps are arranged so that they do not extend beyond the balloon tires of the front wheels.

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

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.

The straddle-type four-wheeled vehicle 1 shown in FIG. 1 has two front wheels 3 and two rear wheels 4 each mounted on a frame 2 shown in FIG. Tires with a wide 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 upper 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
_A space A is formed between the engine ₂₈ , the fuel tank 29, and other equipment. 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 axle 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 pieces 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 rear cover 9 are closed by placing the seat 10 thereon.

The role of each main equipment for 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.
It is screwed 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-wheel vehicle of the present invention, an engine attachment portion is provided on each of the inclined portion of the upper frame and the reinforcing frame, and the upper frame is attached to the upper frame via these attachment portions. The engine is mounted in a space surrounded by the inclined part, the horizontal part of the lower frame, and the reinforcing frame, and a step bar supporting the steps at both ends is attached to the horizontal part of the lower frame, facing the lower surface of the engine. The engine can be protected from obstacles, and other equipment can also be placed in the space. Furthermore, since the step bar is disposed between the lower frames directly below the engine, the rigidity of the central portion of the lower frame, which bears the heaviest load, can be maintained. Furthermore, since the bar steps do not protrude from the outside of the balloon tires of the front wheels, accumulated snow, snow adhering to other objects, or plants do not come into direct contact with the feet while the vehicle is running.

[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)

[Claims] 1 The front and rear wheels of the frame are equipped with two front wheels and two rear wheels each equipped with balloon tires, and the seat is mounted from the rear of the steering head, which rotatably supports the steering shaft to the frame, toward the rear of the vehicle body. The front two wheels are steered by a bar handle supported at the upper end of the steering shaft, and steps are placed on the left and right sides of the vehicle body between the front and rear wheels, and an engine mounted between the front and rear wheels drives the wheels. A straddle-type four-wheeled vehicle configured to travel, wherein the frames are each connected to a pair of upper and lower frames, and a plurality of spacers that connect the upper and lower frames to each other and the upper and lower frames to each other. The upper frame is bent forward diagonally downward and the tip is connected to the axle, and the bent part continues behind the bent part and slopes downward at a gentle angle for a predetermined length. The lower frame is composed of an inclined part and an extended rear end continuous to the rear of the inclined part, and the lower frame is continuous with a horizontal part whose tip is connected to the axle and the rear end of the horizontal part. It consists of a bent part and a rear end part that is continuous with the bent part and connected to the rear end part of the upper frame, and a reinforcing part is provided between the tip part of the upper frame and the horizontal part of the lower frame. The frames are provided diagonally across, and between the middle part of the spacer frame that connects the rear ends of the upper frame and the middle part of the spacer frame that connects the rear ends of the horizontal parts of the lower frame. One reinforcing frame is connected in the vertical direction, and an engine mounting part is provided on the inclined part of the upper frame and the reinforcing frame, and the inclined part of the upper frame and the horizontal part of the lower frame are connected through these mounting parts. The engine is mounted in a space surrounded by a reinforcing frame, and a step bar supporting the above-mentioned steps at both ends is attached to the horizontal part of the lower frame, facing the bottom of the engine, and the left and right steps are connected to the front wheels. A frame structure for a straddle-type four-wheel vehicle characterized by a structure in which the balloon tires are arranged so that they do not protrude outside.