JPS6033180A - Car for travelling on wasteland - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small vehicle for running on rough terrain, which is provided with two mechanical drum brakes on a pair of left and right steering front wheels equipped with small-diameter wide tires.

In this type of small vehicle, if the drum brake is installed deep inside the wheel, the brake wire (Bowden wire) extending from the brake shoe plate will be forced to bend.
Sufficient braking force may not be obtained - for this reason, it is desirable to provide the brake shoe plate as far away from the wheel center plane as possible toward the center of the vehicle body. In addition, the kingpin or ball joint (hereinafter referred to as the kingpin), which supports the front wheel so that it can swing from side to side, should be placed appropriately close to the center plane of the tire, and the kingpin offset (the point where the kingpin extension intersects with the road surface and the tire It is required to reduce the distance (distance from the center of ground contact) to an appropriate level and reduce the steering force of the steering wheel.

That is, it is desirable that the brake shoe plate be provided far from the wheel center plane, and that the king pin be provided close to the wheel center plane. However, the front wheel, which is equipped with a small-diameter, wide, ultra-low-pressure tire, has a small rim diameter and a small brake drum diameter.

It is not possible to provide a concave portion in the brake shoe plate that recesses toward the outside of the vehicle body (toward the brake drum side) and to allow the lower part of the king pin to enter the concave portion, as in the case of a conventional large-diameter rim and brake. As a result, the brake shoe plate tends to go deep into the wheel and interfere with the brake wire or the wheel or tire, and the king pin offset and king pin inclination angle become large, resulting in an increase in non-driving steering force.

The present invention was made in view of these circumstances.

Despite having a pair of left and right front wheels equipped with small diameter wide tires, each of these front wheels was equipped with a mechanical drum brake operated by a Bowden wire.
By arranging the brake shoe plate far from the wheel center plane and the king pin close to the wheel center plane, the curvature of the brake wire is made gentler so that sufficient braking force can be obtained. The purpose is to provide a small-sized vehicle for running on rough terrain that can reduce the power required.

In order to accomplish this internally, the present invention connects a cylindrical part fixed to the front wheel axle that supports the front wheel with a king pin to a knuckle fixed to the front axle to form a so-called Eliot type front wheel support structure, and the brake A shoe plate is disposed close to the connecting portion between the front wheel axle and the cylindrical portion.

The present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a partially enlarged view of FIG. 2.

In these figures, reference numeral 10 denotes a frame (c) A pair of left and right front tubes 12 (12A, 12B) extend diagonally downward and forward from a steering shaft cylinder (not shown) at the front of the frame.

A single rear tube 14 is fixed diagonally downward and rearward. A lower tube 16 extending in the longitudinal direction is fixed to the lower end of the rear tube 14, and a front axle 18 is fixed laterally to the front end of the lower tube 16 and the lower end of the front tube 12. A pair of left and right rear wheels 2 are located at the rear of the frame 1°.
0 (only one of which is shown in FIG. 1) is stored. This rear wheel 20 is equipped with a wide ultra-low pressure tire (a so-called balloon tire with an air pressure of about 0.15 to 0.2 K9/crl in gauge pressure). 22 is the engine mounted near the center of the vehicle, and 24 is the straddle-type driver's seat.

26 is a fuel tank. A steering shaft 28 is rotatably held in the steering shaft/tube of the frame 10, and its lower end is supported by a bracket provided on the front axle 18. 30 is a steering handle attached to the upper end of the steering shaft 28.

32 (32A, 32B) are a pair of left and right front steering axles, which are equipped with wheels 34 and wide ultra-low pressure tires 36.

The rim 38 of the wheel 34 has left and right rim halves 38a, 38.
This is a so-called two-piece structure formed by overlapping the flange portions of b. This rim 38 has a large rim width and a small rim inner diameter.

A substantially U-shaped knuckle 4o that opens toward the side of the vehicle body is fixed to both ends of the front axle 18 of the frame 10. 42
2 is a front wheel axle, and 44 is a cylindrical portion, both of which are made integrally. The cylindrical portion 44 is connected by a king pin 46 in a U-shaped opening at 4 degrees of the knuckle, forming a so-called elliptical front wheel support mechanism.

A hub 48 is rotatably held on the front wheel axle 42.

This hub 48 has a mechanical drum brake 50 (50 people 5
0B) drum 50a is fixed. This hub 48
The flange of the rim 38 is fixed to the flange member 50b fixed to the flange member 50b, and as a result, the brake 50
It will be located on the central plane A of 4. A brake shoe plate 50C that supports the brake shoe 52 is fixed near the connection portion of the front wheel shaft 42 to the cylindrical portion 44. The main wheel shaft 42 is fixed to the upper part of the cylindrical part 44, and as a result, the lower part of the cylindrical part 44 extends downward from the cylindrical part 50c. The king pin 46 is tilted as shown in FIG.

The amount of deviation (kingpin offset) e of the intersection B between the extension line and the ground from the tire ground contact center C is determined. Therefore, the vicinity of the lower part of the king pin 46, that is, the lower part of the knuckle 40 protrudes below the shoe plate) 50C, and when viewed from the front (Fig. 3), the lower part of the knuckle 40 is the shoe plate) 5
It overlaps with the surface on the cylindrical portion 44 side of 0C. Third
In the figure, X indicates the amount of overlap.

A cam lever 58 is attached to a cam shaft 54 that pushes the brake shoe 52 open and presses the brake shoe 52 against the inner surface of the brake drum 50a.

This cam lever 58 is connected to the shoe plate 50C and the cylindrical portion 44.
It extends forward through the space.

60 is a front fender, and an equalizer 62 is attached to the front tube 12 with a bracket 64 on the lower side of this fender 60.
Fixed. The operating force of the pusher 66 provided on the nondle 30 is transmitted to the equalizer 62 via a brake wire 68 using a Bowden wire consisting of an outer tube and an inner wire, and the two equal operating forces distributed by the equalizer 62 are transmitted to the equalizer 62. It is transmitted to the left and right cam levers 58 (only one is shown) via brake wires 70A and 70B made of wires.

The wire 70 connects to the guide 7 that is missing from the shoe plate 50C.
2 (72A, 72B) and rises upward from the cam lever 58 side, and curves around the upper part of the wheel 34 and tire 36 with a gentle curvature.

This embodiment operates as follows. Said Nondol 30
, the rotation causes the pitman arm 72 . fixed to the lower end of the steering shaft 28 to rotate. Tie rod.

The front wheel 32 is rotated left and right via a tie rod arm (both not shown). Since the knuckle 40 is on the side of the front axle 18, the cylindrical part 44 can be brought very close to the shoe plate 50C without making the kingpin inclination angle θ (see Section 3) excessive. It becomes possible to appropriately reduce the king pin offset e. For this reason, this type of tire normally makes steering difficult3
6, the steering becomes appropriately light. knuckle 4
The lower part of the wheel 34 extends below the brake 50, but since the rim width of the wheel 34 is large, the vicinity of the knuckle 40 is located within the wheel 34, and road protrusions do not hit them. Further, since the shoe plate 50C can be arranged close to the king pin 46, that is, with a sufficiently large deviation toward the center of the vehicle body from the wheel center plane A, this shoe plate 50C
The brake wire 70 connected to 0C can be arranged with a gentle curvature without interfering with the wheel 34 or the tire 36, and an increase in resistance due to bending of the wire 70 can be suppressed.

Note that when a ball joint is used instead of a kingpin, the lower ball joint corresponds to the lower part of the knuckle.

In the present invention, as described above, the front wheel support structure is of the elite type, and the brake shoe plate of the brake is disposed close to the joint between the front wheel shaft and the cylindrical portion.

The king pin can be placed close enough to the wheel center plane, and the shoe plate can be placed far enough from the wheel center plane to reduce steering force, while the brake wires are made loose without curvature to reduce wire resistance and provide a sufficiently large control force. The effect of being able to generate power is obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a partially sectional front view thereof, and FIG. 3 is a partially enlarged view of FIG. 2. 18...front axle, 32...front wheel, 36...tire. 40...Knuckle, 42...Front wheel axle, 44...Cylinder part. 50...Drum brake. 50C...brake shoe plate. 68.70...Brake wire. Patent applicant Yamaha Motor Co., Ltd. Agent Patent attorney Yama 1) Yu Moon

Claims (1)

[Claims] A rough terrain vehicle is equipped with a pair of left and right steering front wheels equipped with small-diameter wide tires, and each of these front wheels is equipped with a mechanical drum brake operated by a Bowden wire. The installed cylinder part is connected to the knuckle fixed to the front axle with a king pin,
A vehicle for running on rough terrain, characterized in that a brake shoe plate of the brake is disposed close to a connecting portion between the front wheel shaft and the cylindrical portion.