JPH0692234B2 - Frame structure of saddle type four-wheeled vehicle for traveling on rough terrain - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame structure for a saddle type four-wheeled vehicle for traveling on uneven terrain.

[0002]

2. Description of the Related Art Vehicles used for running on rough terrain are
It is required that the driver easily balances when riding and traveling, and that the maneuverability is good. Therefore, conventionally, a three-wheeled vehicle, which is an improved two-wheeled vehicle, has been widely used. However, structurally, the frame of the two-wheeled vehicle is provided with two rear wheels, which is within the range of the two-wheeled vehicle. Therefore, we have developed the prior art in which a steering shaft of a three-wheeled vehicle is provided with two front wheels to make it a four-wheeled vehicle (actual development 55-
(No. 135686, No. 56-73694)
.

In the four-wheeled vehicle described in this prior art, a fork having a bifurcated lower end of a shaft is used to support the front wheel, and the front wheel is provided outside each of the branched forks. Moreover, tires having the same width as the rear wheels are mounted on the front wheels, and the front fenders and the rear fenders that cover the upper portions of these tires are integrally formed with the cover part that covers the center of the frame. Therefore, even though the front wheels are two wheels, such a prior art one has only the same function as one wheel because it is directly connected to the fork. Especially, since two tires having the same width as the rear wheels are mounted, Was extremely heavy, and the maneuvering performance had deteriorated.

Therefore, a shaft extending in the front-rear direction of the vehicle body is provided at the lower end of the steering shaft, and front wheel support members that rotate independently about the shaft center are attached to the shaft.
A front two-wheel suspension system for a four-wheeled vehicle has been developed in which left and right front wheels are mounted on the front wheel support member (Japanese Patent Laid-Open No. 55-1027).
14 publication).

In this four-wheeled vehicle, in order to reduce the load applied to the steering shaft, the width of the balloon tire of the front wheel is made narrower than the width of the balloon tire of the rear wheel, and the coil spring device is provided on the front wheel support member to enhance the cushioning property. I was taking measures such as.

[0006]

A saddle-ride type four-wheeled vehicle for traveling on uneven terrain is a four-wheeled vehicle in which a bar handle is steered over snowy, muddy land, forest roads, and other uneven terrain, and front and rear wheels are provided with balloon tires. Since the car runs on the road, it requires a light steering force that will not get tired. Also, because it is traveling on uneven terrain, impact on the driver,
It is necessary to effectively absorb the vibration.

However, in the above-described saddle-ride type four-wheel vehicle of the prior art, since the left and right front wheels are supported directly on the lower end of the steering shaft or via the front wheel support members, the load applied to the front wheels during traveling is directly , Will be transmitted to the steering shaft. Therefore, the steering wheel operation for operating the steering shaft becomes heavy, and the steering performance cannot be improved even if the width of the balloon tire is narrowed. Further, since the load is received by the steering shaft of the coil spring device provided on the front wheel support member, the impact applied to the front wheels during traveling is transmitted to the steering shaft as it is, which affects the steering performance. Further, since the front wheel support member is supported by the steering shaft, the length of the front wheel support member is limited, and in the end, the width between the front wheels cannot be set to a width sufficient to obtain running stability.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, reduces the operation of the steering shaft, improves the steering performance, and improves the frame rigidity of a saddle-ride type four-wheel vehicle for traveling on uneven terrain. It is intended to provide a frame structure.

[0009]

In order to solve the above-mentioned problems, the present invention comprises a saddle-type upper frame and a lower frame which constitute a frame, and a balloon tire is attached to the front left and right and the rear left and right of the frame. A front seat and a rear wheel are provided for each of the two wheels, and a seat is vertically placed in the center of the frame from the rear of the shaft supporting portion that rotatably supports the steering shaft with respect to the frame toward the rear of the frame. The front two wheels are steered via the knuckle arm on the front wheel side linked to the lower end of the steering shaft with the bar handle provided on the upper end, and steps are arranged between the front and rear wheels on the left and right of the frame below the seat,
A straddle-type four-wheeled vehicle that drives a wheel by an engine mounted between front and rear wheels and travels on rough terrain, wherein an extension part extending downward is provided at the front part of the upper frame. The lower end of the portion is connected to the lower frame, the upper end of the suspension unit that suspends the front wheels is supported in the middle of the extending portion, and a lateral direction is provided between the extending portions on the upper side of the suspension unit. The bridge members are connected.

Further, according to the present invention, a frame is constructed by an upper frame and a lower frame which are constructed in a saddle type, and two front wheels and two rear wheels equipped with balloon tires are provided on the front left and right sides and the rear left and right sides of the frame. , A vertically long seat is placed in the center of the frame from the rear of the shaft support that rotatably supports the steering shaft to the frame toward the rear of the frame, and the bar handle provided on the upper end of the steering shaft lowers the steering shaft. The front two wheels are steered via the knuckle arm on the front wheel side that is linked with the wheel, and the steps are arranged between the front and rear wheels on the left and right of the frame below the seat, and the wheels are driven by the engine mounted between the front and rear wheels. A saddle-ride type four-wheeled vehicle that travels on level ground, wherein an extension part extending downward is provided at the front part of the upper frame, and the extension part is provided. The lower end connected to the lower frame,
In the middle of the extension part, a vertical bridge member that supports the upper end of the suspension unit that suspends the front wheels and connects the extension part side of the upper frame above the suspension unit and the lower frame side is connected. It is provided.

[0011]

[Operation] The saddle type four-wheeled vehicle for traveling on an uneven terrain according to the present invention,
Straddle the seat, put your foot on the step, grasp the bar handle, and board. The riding attitude is similar to that of a motorcycle.
Then, the engine is operated to start traveling.

Since the balloon tire is a low-pressure wide tire, when it comes into contact with an obstacle such as a stone or rides on it, it deforms freely and absorbs shock to some extent. In particular, since the front wheel is supported by the frame by the support arm and the suspension unit, the vibration due to the unevenness of the road surface is efficiently absorbed. When the bar handle is operated during a curve, the front left and right wheels roll from the steering shaft via the link mechanism and the knuckle arm. At this time, the driver stiffens his / her feet in steps to assist in steering in a curve by moving the weight.

The suspension unit for suspending the front wheels absorbs an impact caused by traveling on rough terrain and transmits the impact to the extending portion of the upper frame. Since the extending portions of the left and right upper frames are connected by the bridge tube, bending stress transmitted to the frame can be prevented.

On the other hand, since the extension portion side and the lower frame side of the upper frame are connected by the longitudinal bridge tube, the extension portion of the upper frame, the lower frame and the bridge tube form a triangle, so that the frame rigidity is increased. Can be improved.

[0015]

The present invention will be described in detail below with reference to the illustrated embodiments.

FIG. 1 is a perspective view showing a saddle riding type four-wheeled vehicle for traveling on uneven terrain according to the present invention, and FIG. 2 is an exploded view of a front wheel suspension system for a saddle riding type four-wheeled vehicle for traveling on an uneven terrain. FIG. 3 is a perspective view, FIG. 3 is a plan view of FIG. 2, and FIG. 4 is an exploded perspective view of a front wheel suspension system for a saddle-ride type four-wheeled vehicle for traveling on rough terrain having a front suspension and a rear suspension according to another embodiment of the present invention. Is.

In FIGS. 1 and 2, reference numeral 1 denotes a saddle-riding type body, in which a front frame 3 and a rear wheel 4 are provided on a narrow frame 2 constructed as shown in FIG. These wheels 3 and 4 are provided with so-called balloon tires 5, which are tires having a low internal pressure and a wide contact surface with the ground. The steering mechanism for steering the wheels 3 and 4 includes:
As the link mechanism 6 as shown in FIG. 3 and a handle for operating the link mechanism 6, a bar handle 7 having grips 701 at both ends is used.

The structure of the frame 2 will be described with reference to FIG. The frame 2 includes a pair of upper frames 8
_1, 8 ₂ and lower frames 9 _1, 9 _2, and a plurality of spacer frames 10 for keeping a predetermined space between the upper frames 8 _1, 8 ₂ and between the lower frames 9 _1, 9 ₂ Has been done.

The upper frame 8 _1, 8 ₂ has a tip portion 80.
1 is bent forward and obliquely downward to form an extending portion extending downward, and a rear end of the bending portion 802 is formed with a predetermined length of an inclined portion 803 inclined downward at a gentle angle. The rear end portion 804 behind the inclined portion 803 is horizontally or slightly bent upward. The tip of the upper frame _81, 82 are connected by spacer frame 11, and the distal end portion 8
A U-shaped fixing frame 13 for fixing the front cover 12 with a screw is mounted between the parts 01. The upper frame _81, 82 of the bent portion 802, a steering head 15 as shaft support for rotatably supporting the steering shaft 14 of the bar handle 7 is provided.

On the other hand, the lower frames 9 _1, 9 ₂ are connected at their tips by a spacer frame 11, and the rear ends 901 are bent to stand up, and the rear ends of the upper frames 8 _1, 8 ₂ are raised. Each of them is connected to the section 804.

Between the front wheel 3 and the rear wheel 4, under the seat
The lower frame 9_1,9₂In the middle of the
A bar step 16 is attached as a step. this
Width l between bar steps 16₁The left and right front wheels 3,
Width l between 3₂Against l ₁<L₂Set to
And the width l between the front wheels 3 and 3₂Between the rear wheels 4 and 4
Width of₃For l₂<L₃Is set to be
There is.

The diameter d ₁ of the front wheels 3, 3 and the tire width W ₁ are d with respect to the diameter D and the tire width W of the rear wheels 4, 4.
_By setting ₁ <D, W ₁ <W, the front wheels 3 and 3 are easily steered. The lower frame 9 _1, 9 ₂ of the bent portion 902, support portion 903 which supports the drive shaft 17 of the rear wheel 4 through bearings (not shown) is provided.

The engine 18 is placed in the space A formed by the upper frames 8 _1, 8 ₂ and the lower frames 9 _1, 9 _2.
A fuel tank 19 and the like are mounted.

Next, a steering mechanism for steering the front wheels 3 will be described with reference to FIGS. 2 and 3. The front wheel 3 is steerably attached to a U-shaped wheel support frame 20 supported by the spacer frame 11 and the lower frames 9 ₁ , 9 ₂ .

The frame 20 includes a spacer frame 11 and lower frames 9 ₁ and 9 ₂ to which a ball joint 2 is attached.
1, a front support arm 22 ₁ and a rear support arm 22 ₂ whose _one ends are swingably supported, and an upper frame 8 _1,
It is supported by a front suspension composed of a suspension unit 23 whose upper end is supported in the middle of the front end portion 801 of 8 ₂ .

The suspension unit 23 has its upper end supported by a bracket 23a in the middle of the front end 801 of the upper frames 8 _1, 8 ₂ and its lower end supported by the upper surface of the front wheel support frame 20 via a bracket 23b. Has been done. The suspension unit 23 is disposed obliquely forward from the upper frames 8 _1, 8 _{2 when} viewed from the front, and is tilted so as to spread downward on both sides.

The upper frame 8 _1, 8 ₂ tip portion 801 on the upper side of the bracket 23 a of the suspension unit 23
A bridge tube 111 for reinforcement is connected to each other.

A longitudinal reinforcing bridge tube 112 is provided between the front end portion 801 of the upper frame 8 _1, 8 ₂ provided with the reinforcing bridge tube 111 and the lower frame 9 _1, 9 ₂ . .

The front wheel 3 is a support pipe integrally provided on a wheel support shaft (not shown), and is provided with a kingpin by a frame 2
It is performed by pivoting to 0.

The upper end of the steering shaft 14 is rotatably supported by the pivotal support of the steering head 15, and the lower end of the steering shaft 14 is rotatably supported by a support 24 provided at an intermediate position of the spacer frame 11. It is supported. An arm 25 is attached to a lower end portion of the steering shaft 14, and one end portions of left and right tie rods 26 are rotatably supported by the arm 25 via a pin 27. A ball joint 28 is inserted in the middle of the tie rod 26, and the other end of the tie rod 26 is rotatably supported by a knuckle arm 29 mounted on a support pipe via a pin 30. As a result, the steering shaft 14 and the front wheel 3 are connected by the link mechanism 6, and the front wheel 3 is operated by operating the bar handle 7.
Is steered.

Next, returning to FIGS. 1 and 2, the body 1
The cover disposed as the exterior of the vehicle is divided into two parts, the front cover 12 and a rear cover 31 combined with the front cover 12, and the front cover 12 and the rear cover 31 respectively include the front fender 121 and the rear fender 311. It is formed integrally. Reference numeral 32 denotes a seat, which is placed vertically in a substantially central portion of the frame 2 from a rear portion of a shaft supporting portion that rotatably supports the steering shaft 14 toward the rear of the frame 2.

When driving the saddle-ride type four-wheeled vehicle for traveling on rough terrain according to the present invention, the driver puts his / her foot on the step 32 while straddling the seat 32 and grips 7 of the bar handle 7.
Hold 01 with both hands and drive. Then, in order to make a left turn, a right turn, a turn, etc., the bar handle 7 is rotated in a desired traveling direction like an ordinary motorcycle. In response to this, the steering shaft 14 rotates by a predetermined angle, and the link mechanism 6 is operated in accordance with the rotation of the arm 25.
As a result, the front wheel 3 having a width smaller than that of the rear wheel 4 can be easily steered by a necessary angle and the traveling direction of the vehicle body can be changed despite the balloon tire having a larger tire contact area than the normal tire. When making a sharp turn, when the weight of the front suspension unit 2 is changed while the direction of the bar handle 7 is changed.
With the compression of 3, the inner tire balloon tire 5 is dented, which fulfills the same function as the differential gear of a normal four-wheeled vehicle.
A sharp turn is made.

At this time, since the impact is absorbed by the action of the balloon tire 5 and the front suspension unit 23, the driver can drive stably.

The suspension unit 23 is viewed from the front,
Since it is arranged at an angle that spreads diagonally forward, a sufficient stroke can be secured. Further, bending stress acts on the tip portions 801 of the upper frames 8 _{1 and} 8 _{2 due to} the expansion and contraction in the oblique direction, but the bridge tubes 111 and 112 can ensure rigidity.

Next, FIG. 4 shows another embodiment of the present invention in which a front suspension and a rear suspension are provided. The same parts as those in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted. Show.

The frame structure includes a lower frame 9 ₁ of FIG. _2,
The middle of 9 ₂ is cut at the rear side of step 16, and the frame 9 ′ is cut between the cut portions of the lower frames 9 ′ ₁ and 9 ′ _2.
1, 9 'are connected by longer joint pipe 33 ₂ width. Then, the joint pipe 33 and the upper frame 8
_1, 8 ₂ rear ends are connected by side frames 34,
Joint pipe 3 in these side frames 34
The connecting portion with 3 is set to be larger than the interval between the lower frames 9 ′ ₁ and 9 ′ ₂ .

On the other hand, the upper frames 8 _1, 8 ₂ and the joint pipe 33 are connected by two main frames 35, and a swing arm 36 for supporting the drive shaft 17 is attached to the main frames 35. There is. In this swing arm 36, one ends of two arms 361 are connected by a support shaft 362, and the support shaft 362 is swingably supported by the main frame 35. A mounting hole 363 is provided at the other end of each arm 361 of the swing arm 36.
Is provided, and the drive shaft 17 is supported in the mounting hole 363 via a bearing (not shown).

A single rear suspension unit 37 is provided between the other end of the swing arm 36 and the upper frames 8 _1, 8 ₂ . The rear suspension unit 37 includes a spacer frame 10 whose one end is connected between the rear ends 804 of the upper frames 8 _1, 8 _2.
To the swing arm 36 at the other end.
The frames are connected to one another by a frame 365.

The front suspension is the same as in FIG.
The upper frame _81, 82 of the distal portion 801 therebetween, the lateral reinforcing bridge tube 111a, 111b are provided, stretch acting on accompanying the upper frame _81, 82 tip portion 801 of the suspension units 23 Bending stress is prevented. The spacer frame 101 hung between the bridge tube 111a and the lower frames 9 ′ ₁ and 9 ′ ₂ has one vertical bridge tube 112.
a is connected.

According to the straddle-type four-wheeled vehicle for traveling on rough terrain, the suspensions 23 and 37 are provided on both the front wheels 3 and the rear wheels 4, so that comfortable riding is possible when traveling on rough terrain. Obtainable. The frame has an upper frame _81, 82 of the distal portion 801 bridge tube 111a therebetween, 111b are provided, and the upper frame _81, 82 of the distal end portion 801 and the lower frame 9 '
_1, 9 'so between _two mutually linked by a bridge tube 112a, from bending stress exerted on the upper frame _81, 82 tip portion 801 due to the expansion and contraction of the suspension unit 23, it is possible to protect the frame.

The rear suspension unit 37
Is two provided even better between the arms 361 of the upper frame _81, 82 and the swing arm 36, The arm 36
1 may be independently supported, and the rear suspension unit 37 may be separately provided between each arm 361 and the upper frames 8 _1, 8 ₂ .

[0042]

As described above, according to the frame structure of the saddle-ride type four-wheel vehicle for traveling on rough terrain according to the present invention, the following effects can be obtained.

A suspension unit is provided at the front portion of the upper frame, which has a downwardly extending extension portion, whose lower end is connected to the lower frame, and which suspends the front wheel in the middle of the extension portion. Since the upper end of the suspension unit is supported and a lateral bridge member is connected between the extending portions on the upper side of the suspension unit, frame rigidity can be improved. Therefore, it is possible to sufficiently cope with the bending stress of the tip portion of the upper frame due to the expansion and contraction of the suspension unit due to traveling on an uneven terrain.

Further, since a vertical bridge member for connecting the extension portion side of the upper frame on the upper side of the suspension unit and the lower frame side is provided, a triangle is formed between the tip portion of the upper frame, the lower frame and the bridge member. Since it is formed, the frame rigidity can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a saddle riding type four-wheeled vehicle for traveling on an uneven terrain according to the present invention.

FIG. 2 is an exploded perspective view showing an embodiment of a frame structure of a saddle-ride type four-wheeled vehicle for traveling on rough terrain according to the present invention.

FIG. 3 is a plan view of FIG.

FIG. 4 is an exploded perspective view showing another embodiment of the present invention.

[Explanation of symbols]

1 Body 2 Frame 3 Front Wheel 4 Rear Wheel 5 Balloon Tire 6 Link Mechanism 7 Bar Handle 8 _1, 8 ₂ Upper Frame 9 _1, 9 ₂ Lower Frame 11 Spacer Frame 14 Steering Shaft 17 Drive Shaft 20 Wheel Support Frame 22 ₁ Front Side Support arm 22 ₂ Rear support arm 23 Front suspension unit 32 Seat 111 Bridge tube 111a, 111b Bridge tube 112 Bridge tube 112a Bridge tube

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiki Shinohara 1299-54 Tomitsuka-cho, Hamamatsu City, Shizuoka Prefecture

Claims (2)

[Claims] 1. A frame is composed of an upper frame and a lower frame, which are straddle-type, and two front wheels and two rear wheels equipped with balloon tires are provided on each of the front left and right sides and the rear left and right sides of the frame. On the other hand, a vertically long seat is placed approximately in the center of the frame from the rear of the shaft support that rotatably supports the steering shaft toward the rear of the frame, and the bar handle provided on the upper end of the steering shaft links with the lower end of the steering shaft. The front two wheels are steered via the knuckle arms on the front wheels, and the steps are arranged between the front and rear wheels on the left and right of the frame below the seat, and the engine mounted between the front and rear wheels drives the wheels to drive on rough terrain. In the saddle-ride type four-wheeled vehicle, a downwardly extending extension portion is provided at the front portion of the upper frame, and a lower end of the extension portion is provided at the lower portion. The suspension unit for suspending the front wheels in the middle of the extending portion, and a lateral bridge member is connected between the extending portions on the upper side of the suspension unit. A frame structure for a saddle-ride type four-wheeled vehicle for traveling on rough terrain. 2. A frame is composed of a saddle-type upper frame and a lower frame, and two front wheels and two rear wheels equipped with balloon tires are provided on each of the front left and right sides and the rear left and right sides of the frame. On the other hand, a vertically long seat is placed approximately in the center of the frame from the rear of the shaft support that rotatably supports the steering shaft toward the rear of the frame, and the bar handle provided on the upper end of the steering shaft links with the lower end of the steering shaft. The front two wheels are steered via the knuckle arms on the front wheels, and the steps are arranged between the front and rear wheels on the left and right of the frame below the seat, and the engine mounted between the front and rear wheels drives the wheels to drive on rough terrain. In the saddle-ride type four-wheeled vehicle, a downwardly extending extension portion is provided at the front portion of the upper frame, and a lower end of the extension portion is provided at the lower portion. A vertical frame connecting the extension part side and the lower frame side of the upper frame above the suspension unit while supporting the upper end of the suspension unit suspending the front wheels in the middle of the extension part. A frame structure for a saddle-ride type four-wheel vehicle for traveling on uneven terrain, characterized in that a bridge member for the direction is provided.