JPH06179389A - Suspension structure for vehicle with crawler - Google Patents

Abstract

PURPOSE:To allow a lean angle to be made large with a step shifted afterward without widening the width of the step even if the width of a crawler is wide as well as to enhance run-over performance over a field covered with fresh snow. CONSTITUTION:The pivot axis 30 of a swing arm 36 is located behind a step P2 while being located roughly above the crawler ground plane in the flat ground surface, a suspension 25 for a crawler frame is disposed ahead of the pivot axis 30, and concurrently an upper eye at the upper installation end of the suspension 25 is fixed onto any lower section frame other than the swing arm 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension structure for a vehicle with a crawler which runs on snow by driving a rear crawler supported by a rear end of a rear swing arm, and more particularly to a suspension structure for smoothing a suspension stroke.

[0002]

2. Description of the Related Art Conventionally, there is a small snow vehicle in which a front wheel or a sled is attached to a front hawk, a crawler (crawler track) is attached to a rear portion, and the crawler is driven by an engine so that the vehicle can travel on snow (Japanese Patent Laid-Open No. 2-262488). (See the official gazette). However, there has been no conventional small snow vehicle capable of handling various road surfaces such as a soft snow surface with fresh snow, a hard snow surface that has been compacted, or a snow-free road surface. On the other hand, the applicant has already filed a Japanese patent application No. 3-15 for a small snow vehicle capable of handling various road surfaces and improving running performance on snow.
2329 (unknown).

FIG. 5 shows the structure of this small snow vehicle. In FIG. 5, the engine a drives the rear chain d via the continuously variable belt transmission b and the gear reducer c, and further drives the drive sprocket e. The crawler f is driven by the driving force of the drive sprocket e, pushes the snow surface backward, and advances the small snow vehicle. The crawler f is wound around the drive sprocket e and the free sprocket g. Further, the crawler f is inflated downward and expanded on the idlers h1 to h4 provided on the crawler frame h together with the sprockets e and g, and extends long in the front-rear direction of the vehicle body to near the rear side of the front fork i. It has been overrun. The crawler frame h includes a swing arm j
Has one end thereof coaxially supported by the drive sprocket e.
The other end of the swing arm j is pivotally supported on a pivot shaft j1 near the output sprocket of the gear reducer c behind the vehicle lower frame k. Also, the swing arm j
One end side of each of the upper and lower suspensions 1 and m is connected to. The other end (upper eye) of the upper suspension 1 is pivotally supported on the lower part of the frame (rear frame) k, and the other end (under eye) of the lower suspension m is pivotally supported on the upper side of the crawler frame h. Note that the other configurations are described in the above-mentioned application, and therefore the description thereof is omitted.

The present inventor has carried out various runs on this small snow vehicle. At this time, in the small snow vehicle, the front wheel shared load is 40 to 45% of the normal motorcycle shared load.
It was found that if the weight is not lightened, the front wheels will easily sink into the snow, and sometimes the running performance and handling performance will not be what you expect. In order to eliminate such inconvenience, as shown in FIG. 5, the position of the step should be set slightly from the center position p1 of the lower frame conforming to a general motorcycle to a position slightly smaller than the center position where the crawler f comes in contact with the ground on a hard road surface. It has been found that it is optimal to set the position p2 in front of and slightly behind the pivot axis j1 of the swing arm j.

[0005]

However, in the small snow vehicle (vehicle with crawlers), the chain (rear chain) has to be arranged outside the crawlers, and the front end of the chain is forward of the step. Since it extends to, the width between both steps becomes too wide. This has the problems that the driver's legs become too wide and the bank angle tends to decrease.

The present invention has been made to solve the above-mentioned conventional problems, and even if the width of the crawler is wide, the step with the crawler can be shifted rearward and positioned without widening the step width. It is an object to provide a suspension structure of.

[0007]

SUMMARY OF THE INVENTION The present invention drives a rear crawler supported by the rear end of a rear swing arm, and a predetermined portion of the lower portion of the rear crawler is provided on a crawler frame. In a suspension structure for a vehicle with a crawler that is curved downward by means of a vehicle, the pivot axis of the rear swing arm is located behind the step and almost above the crawler ground contact surface on a flat surface, and the suspension for the crawler frame is However, the above problem is solved by the fact that the upper mounting end of the suspension is fixed to the vehicle body frame other than the rear swing arm while being arranged in front of the pivot shaft.

Further, in the present invention, the crawler frame suspension may be arranged in front of the step. Further, in the present invention, the tangent angle of the rear end shaft of the swing arm and the tangent angle of the lower portion of the rear crawler frame suspension to which the suspension is attached are positive and negative between the states in which the suspension of the rear swing arm is extended to compressed. Can remain the same, and the magnitude relationship of the values can be prevented from being reversed.

[0009]

In the present invention, the pivot shaft of the rear swing arm is located behind the step and substantially above the crawler ground contact surface on the flat surface, and the crawler frame suspension is arranged in front of the pivot shaft. In addition, since the upper mounting end of the suspension is fixed to the body frame other than the rear swing arm, even if the crawler width is wide, the step can be shifted backward without widening the step width, so that a large lean angle can be obtained and fresh snow can be taken. The running performance in is improved.

Further, in the present invention, if the suspension for the crawler frame is arranged in front of the step, the ground contact surface of the crawler makes a stroke according to the change of the road surface terrain, for example, along the change of the terrain, so that the riding comfort and running performance can be improved. The property is improved. In addition, the tangent angle of the rear end shaft of the swing arm and the tangent angle of the lower portion of the rear crawler frame suspension to which the frame is attached remain the same in positive and negative between the states where the suspension of the rear swing arm is extended and compressed. In addition, if the magnitude relationship of the values is not reversed, a dead point cannot be reached in the load change of the suspension, so that a smooth stroke change occurs and the riding comfort is improved.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a block diagram of a small snow vehicle according to a first embodiment of a vehicle with a crawler of the present invention. FIG. 2 shows the pivot shaft 30 of the rear swing arm 18 of this small snow vehicle.
FIG. 3 and 4 show the cushion 2
It is explanatory drawing of the buffering operation by 5,26. In the configuration of FIG. 1, the seat 2 is provided on the upper portion of the vehicle body 1,
A bar handle 4 is connected to the upper end of the front fork 3. The front fork 3 is a bottom link type, and the suspension 5 is expanded and contracted to swing the link 6 to form a cushion for the front wheel 7.

The engine 8 drives a front chain 11 via a continuously variable transmission 9 and a gear reducer 10 to drive a constant velocity universal joint 12. And, furthermore, a constant velocity universal joint 12
From primary chain 13, idler 14, secondary chain 15
The front wheels 7 are driven via. On the other hand, the engine 8 includes the transmission chain 18, the first drive sprocket 31, and the first drive sprocket 31, via the continuously variable belt transmission 16 and the gear reducer 17.
The drive chain 32 is driven to drive the crawler drive sprocket 19. Crawler 20 on this sprocket 19
, The crawler 20 is
Driven by.

The engine 8 is surrounded and supported by a lower frame 33, and an arm frame 35 for rotatably supporting the drive sprocket 31 is provided behind the lower frame 33 and below the rear frame 34. It is fixedly provided on the frames 33 and 34. As shown in FIG. 2, the arm frame 35 is narrower in width than the lower frame 33. The step p2 is provided slightly below the mounting position of the arm frame 35 on the lower rear side of the lower frame 33. A pivot shaft 30 on the front end side of a swing arm 36 is provided coaxially with the rear end of the arm frame 35, that is, the drive sprocket 31, and the rear end of the swing arm 36 pivotally supports the drive sprocket 19. . The swing arm 36 moves up and down with the pivot shaft 30 as a fulcrum according to the up and down movement of the crawler 20.

As shown in FIG. 2, a second drive sprocket 17a is fixed to the output shaft of the gear reducer 17 in the rotational direction. A driven gear 31a fixed to the first drive sprocket 31 in the rotation direction and a rotation side of the brake unit 37 are rotatably supported by the pivot shaft 30. In this case, the fixed side of the brake unit 37 is fixed to the arm frame 35 in the axial direction. The arm frame 35 extends rearward from the lower frame 33, being narrower than its width, narrower than the width of the rear swing arm 36, and extending between the arm 36 and the brake unit 37 to support the pivot shaft 30. ing. Further, the transmission chain 18 is arranged inside the lower frame 33 and bridges the second drive sprocket 17a and the driven gear 31a. Drive sprocket 31 and drive sprocket 1
The drive chain 32 is placed inside the swing arm 36 and bridged over it. Therefore, the driving force of the engine 8 is transmitted in the order of the second drive sprocket 17a → driven gear 31a → drive sprocket 31 → drive sprocket 19 → crawler 20.

The crawler 20 is a crawler belt provided so as to correspond to the rear wheel portion, and is wound between the free sprocket 22 and the drive sprocket 19 to be engaged with each other. Crawler 20
Is a free sprocket 22, a drive sprocket 19, and an idler 2 mounted on a crawler frame 24.
7a to 27d, and extends long in the front-rear direction of the vehicle body 1 to near the rear side of the front hawk 3.

The crawler 20 is rotationally driven by a drive sprocket 19 arranged at the rear end of the crawler 20 and a free sprocket 22 arranged at the front end of the crawler 20. The idlers 27a to 27d are of a so-called central guiding type, for example, guiding a protrusion provided on the inner peripheral side of the crawler 20.

Of the idlers 27a to 27d, the idler 2
Reference numerals 7c and 27d denote rollers that are flat and hard, for example, rollers that come into contact with the ground via the crawler 20 when traveling on a paved road.
This is the roller that receives the impact load first. Further, among the idlers 27a to 27d, the idlers 27a and 27b are rollers that are not grounded via the crawler 20 when traveling on the paved road. Therefore, since the idlers 27c and 27d are the lowest, the crawler 20 is inflated in a state of being inflated downward and curved so that the central rear side is the lowest.

The crawler 20 is formed by laterally burying a core metal (not shown) at predetermined intervals, and is made of rubber. On the inner peripheral side of the crawler 20, a row of engaging holes for engaging the teeth formed on the free sprocket 22 and the drive sprocket 19 to rotate the crawler 20 is provided at the center in the width direction.

Suspensions 25 and 26 are provided between the crawler frame 24 and the vehicle body 1 for cushioning impact. That is, in the crawler frame 24,
The under eye side of one end of the suspension 25 is connected, and the upper eye side of the other end of the suspension 25 is attached to the lower end of the lower frame 33. Further, an under eye side of the suspension 26 is attached to an upper side of the swing arm 36 via an attaching member 36a, and an upper eye side of the other end of the suspension 26 is attached to a lower portion of a rear portion of the rear frame 34. . Therefore, the impact load applied from the crawler 20 is applied to the crawler frame 24, and is transmitted to the vehicle body 1 side via the suspension 25 at the front part of the crawler frame 24. At the rear part, the power is transmitted to the vehicle body 1 side via the swing arm 36 and the suspension 26. In this way, the suspension 25, 26
The above-mentioned impact load is relieved by the expansion and contraction of.

In the present embodiment, as shown in FIGS. 1 to 3, the drive sprocket 31 of the chain 32 for driving the crawler 20 is displaced rearward of step p2, and
Since the transmission chain 18 is arranged inside the lower frame 33, the width between the steps p2 on both sides of the vehicle body is set to the width of the crawler 20 (the drive chain 32 passing outside the crawler 20).
It can be set regardless of the width). Therefore, it is possible to prevent the legs of the driver stepping on this step p2 from becoming wider at the end, and it is easy to lean the vehicle when traveling to increase the bank angle of the vehicle body. Further, if the pivot axis of the swing arm is provided at the position indicated by reference numeral j in the figure, the step width becomes wider in accordance with the spread of the crawler width like step p2a, but in the present embodiment, step p2 is Since it is provided like a solid line, such a thing does not occur. Further, if the suspension of the crawler frame is provided as indicated by symbol m in the figure, the suspension may be a hindrance when riding, but in this embodiment, the suspension is provided earlier, so Nothing happens.

Now, the location where the pivot shaft 31 and the lower suspension 25 are arranged and attached will be described. As shown in FIG. 3, when the pivot shaft 31 is provided in the rear portion of the lower frame 33, the pivot shaft is located near the ground contact surface of the crawler 20 on a hard road surface. Therefore, if the lower suspension 25 is arranged between the crawler frame 24 and the swing arm 36 as indicated by the reference numeral 25a in FIG. 3 (according to the small snow vehicle of FIG. 5), the upper suspension 26 has a stroke. The swing arm 36 may not perform its function (function of making the crawler frame 24 stroke parallel to the road surface). Therefore, the suspension 25 is arranged at the front of step p2, not at the rear of step p2. In the embodiment, the position shown by reference numeral 25 is set instead of the position shown by reference numeral 25a in the drawing. As a result, the ground contact surface of the crawler 20 is
For example, since a stroke is made along the terrain, riding comfort and running performance are improved.

In addition, in the crawler frame suspension 25, the tangent angle β of the lower mounting portion (under eye) of the suspension 25 from the maximum extension to the maximum compression.
a to βb, and the tangent angles αa to αb of the swing arm 36 from the maximum extension to the maximum compression of the suspension 26.
Think about. In the process of changing from the tangent angle βa to βb and from αa to αb, the positive and negative of these angles are reversed, and the magnitude relationship between one value and the other value is changed on the way (the magnitude relationship is reversed). And the cushion stroke of the suspension 25 has a dead point. For example,
When the suspension 25 is set to the alignment shown in 25b of FIG. 3, a dead point is formed in the cushion stroke of the suspension 25 as shown by a broken line in FIG. 4, and the stroke may be difficult. Therefore, in order to prevent such a situation from occurring, the tangent angle αa to α
b and the tangent angle βa to βb have opposite signs,
By setting the suspension 25 in an alignment that does not reverse the magnitude relationship of these values, there is no dead point in the stroke change of the suspension 25 as shown by the solid line in FIG. 4, so the buffering operation of the crawler 20 is smooth. Become.

The present invention is not limited to the structure of the above-mentioned embodiment, and various modes can be adopted within the scope of the present invention. For example, in the above-described embodiment, the upper suspension 26 is disposed on the lower frame 33 and the rear frame 34 via the arm frame, but this arm frame can be integrated with the vehicle body frame. .

[0024]

EFFECTS OF THE INVENTION According to the present invention, even if the crawler has a wide width, the step is shifted rearward without widening the field, so that a large lean angle can be obtained and the running performance in fresh snow is improved. The effect is obtained. Further, in the present invention, if the suspension for the crawler frame is arranged in front of the step, the ground contact surface of the crawler strokes along the terrain according to the change of the road terrain, so that the riding comfort and the running performance are improved. Further, the positive and negative values of the tangent angle of the rear end shaft of the swing arm and the tangent angle of the lower portion of the rear crawler frame suspension attached to the frame remain the same between the states where the suspension of the rear swing arm is extended to the most compressed state. And, and
Since the magnitude relationship of the values is not reversed, there is no dead point in the load change of the suspension, so a smooth stroke change occurs and the ride comfort is good.

[Brief description of drawings]

FIG. 1 is an overall schematic side view showing a small snow vehicle according to an embodiment of the present invention.

FIG. 2 is a detailed configuration diagram showing the vicinity of the pivot axis of the rear swing arm of the embodiment.

FIG. 3 is a partially enlarged view for explaining the operation of the suspension of the small snow vehicle of the embodiment.

FIG. 4 is an operation explanatory view of the suspension of the small snow vehicle of the embodiment.

FIG. 5 is an explanatory diagram of a configuration of a small snow vehicle in the prior application.

[Explanation of symbols]

 18 Transmission Chain 19 Crawler Drive Sprocket 20 Crawler 25 Lower Suspension 26 Upper Suspension 30 Pivot Shaft 32 Drive Chain 35 Arm Frame 36 Rear Swing Arm p2 Step

Claims (3)

[Claims] 1. A rear crawler supported by a rear end of a rear swing arm is driven, and a predetermined portion of a lower portion of the rear crawler is curved downward by a lower roller provided on a crawler frame. In the suspension structure for vehicles with crawlers, the pivot axis of the rear swing arm is located behind the step and almost above the crawler ground contact surface on a flat surface, and the suspension for the crawler frame is located in front of the pivot axis. A suspension structure for a vehicle with a crawler, wherein the suspension is disposed and an upper mounting end of the suspension is fixed to a vehicle body frame other than a rear swing arm. 2. The suspension structure for a vehicle with crawlers according to claim 1, wherein the crawler frame suspension is arranged in front of the step. 3. The frame mounting lower portion of the rear crawler frame suspension and the tangent angle of the swing arm rear end shaft between the states in which the suspension of the rear swing arm is in the most extended state to the most compressed state according to claim 1 or 2. A suspension structure for a vehicle with a crawler characterized in that the positive and negative values of the tangent angle of are kept the same, and the magnitude relationship of the values is not reversed.