JP2002068070A - Overload preventing device for off road traveling vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overload preventing device for an off road traveling vehicle capable of preventing the fracture of a driving system, simplifying a structure, and reducing the number of components, the cost and a weight. SOLUTION: In the vehicle where the motive power is transmitted to an output shaft 8 from an engine through a start clutch, a V belt continuously variable transmission and a sub-gear transmission, a shaft hole 15 of a driven gear 7 engaged with a driving gear 6 of a counter shaft of the sub-gear transmission is press-fitted to the output shaft 8, and a press fit margin is determined to produce the slipping between the driven gear 7 and the output shaft 8 with more than predetermined torque.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to use on uneven terrain in which a rider straddles a saddle-type seat, steers a front wheel with a bar handle, and drives two front wheels and two rear wheels with an engine to travel. The present invention relates to a suitable overload prevention device for an off-road vehicle.

[0002]

2. Description of the Related Art As shown in FIG. 4, in a saddle riding type vehicle on an uneven terrain, a front end portion and a rear end portion are arranged such that a front two wheels A and a rear two wheels B are suspended at right and left intervals. The body C and the like are configured wide, and the wheels A and B are covered by mudguard fenders C1 and C2 from above. Body center C3
The saddle-shaped seat E is provided above the fuel tank D at the front position of the body center C3. The driver F rides on the seat E and places his / her feet on the footrests G that protrude in the body width direction to stabilize the riding posture. The front two wheels A are steered by a handle H standing upright at the front of the fuel tank D, and the front wheels A
The vehicle travels by driving the four rear wheels B. In addition, in order to be suitable for rough terrain traveling, the transmission mechanism has a sub transmission in addition to the main transmission so that the gear ratio is high and wide, and each part is robust and the suspension is set for irregular terrain. is there.

[0003] The above-mentioned vehicle often jumps when traveling on uneven terrain. If the difference between the rotation of the engine and the rotation of the wheels is large at the time of landing, the power transmission system is overloaded due to a shock. There are cases. In this type of vehicle power transmission system, the strength of each part is set in response to the assumed overload. However, if an overload occurs more than expected in actual traveling, the power transmission system must be implemented without any overload prevention mechanism. In some cases, problems such as damage may occur.

Conventionally, as an overload damage preventing device in the power transmission system, there is a device using a mechanical damper as shown in FIG. That is, as shown in the figure, a drive gear K at the end of a counter shaft J of a sub-gear transmission I, which is a sub-transmission provided at the rear of the drive system of the engine, is provided, and a driven gear meshed with the drive gear K is provided. L is rotatably supported on the output shaft M. From this output shaft M to bevel gear Q
Power is transmitted to the propeller shaft R via the. Also,
The cam cylinder N, which is slidably inserted in the output shaft M in the axial direction, is pressed against the driven gear L by the spring O, and the opposing portions of the driven gear L and the cam cylinder N that contact each other are shown in FIG. ), As shown in FIG.
Let me. During normal operation, a rotational torque is transmitted from the driven gear L to the cam cylinder N via the cam mesh P to rotate the output shaft M. When an overload is applied, the cam cylinder N In reverse, the cam mesh P is disengaged, the driven gear L and the output shaft M
This prevents overload from occurring due to slippage between them, thereby preventing the power drive system from being damaged.

[0005]

However, in the above-described overload damage prevention device, the number of processing steps for mounting the cam cylinder N and the spring O and processing the cam meshing P for preventing the damage are increased, and the mounting space is reduced. This has led to an increase in the number of parts, an increase in processing costs, an increase in weight, etc., such as an increase in the size of the engine case. Further, the setting of the transmission torque requires replacement of springs and cams, and it is necessary to prepare parts for each vehicle. Therefore, the parts cannot be shared, which hinders the reduction in the number of parts.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide an overload prevention device for an uneven terrain vehicle that can prevent damage to a drive system, is simple in structure, has few components, is inexpensive and is lightweight. .

[0007]

In order to achieve the above object, the present invention has the following arrangement. The present invention transmits power from the engine to the output shaft from the main transmission via the auxiliary gear transmission, and press-fits the shaft hole of the driven gear meshing with the drive gear of the counter shaft of the auxiliary gear transmission into the output shaft. An overload prevention device for an uneven terrain vehicle, wherein the press fit is set so that a slippage occurs between the driven gear and the output shaft at a predetermined torque or more. In the present invention, it is preferable that the main transmission mechanism is a V-belt type continuously variable transmission provided with a start clutch on the input side. It is also preferable that four wheels be driven from the output shaft via the propeller shaft and the front and rear axles.

Normally, each part of the power drive system of an all-terrain vehicle is set to have a strength that can withstand the maximum output of the engine. If more strength is given to each part, disadvantages such as an increase in weight occur. On the other hand, the vehicle running on rough terrain often jumps while traveling, and when the vehicle lands, the engine rotation does not match the wheel rotation. At this time, a shock exceeding the maximum output of the engine may be applied to the power drive system.

According to the present invention, the driven gear and the out-push shaft of the sub-gear transmission of the drive system are press-fitted so as to slip at a predetermined torque or more, so that they function as a torque limiter. Therefore, when the torque is lower than the maximum output of the engine, the power is transmitted without slipping.However, when a shock exceeding the maximum output of the engine is received, the press-fitted portion slips to prevent damage to the power drive system. Can be. Thus, the drive system can be protected. In addition, compared with the spring damper, the number of parts of the drive system does not increase, the structure is simple, the number of parts and weight do not increase, the mounting space does not increase, and the engine case does not become large.

When the main transmission mechanism is a V-belt type continuously variable transmission provided with a starting clutch on the input side, V
The inertia of the belt transmission is large, and when the vehicle jumps and lands, it changes from no load to a large load, and the load fluctuates easily.The output shaft load tends to be excessive, but in such a case, the output shaft torque It is preferable because overload can be escaped by a limiter. Also,
Even when the four wheels are driven from the output shaft via the propeller shaft and the front, rear, left and right axles, the inertia of each axle is applied to the output shaft, so that the overload can be released by the torque limiter of the output shaft.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The embodiment is an overload prevention device for an uneven terrain traveling vehicle. The overall structure of the all-terrain vehicle is shown in FIG. 4 and will not be described.
FIG. 1 is an explanatory view of an overload prevention device in which a driven gear 7 is press-fitted on an output shaft 8 of an engine unit, FIG. 2 is a detailed explanatory view of a power transmission mechanism of an all-terrain vehicle according to the embodiment, and FIG. FIG.

The engine unit 20 is shown in FIG.
It is provided at the center of the body, and is disposed at a position where the occupant rides over the engine unit. In order to obtain sufficient torque for traveling on uneven terrain, a V-belt type continuously variable transmission 3 is mounted as a main transmission, and a sub gear transmission 4 is mounted as an auxiliary transmission. As shown in FIG. 2, in the engine unit 20, the rotation of the crankshaft 1 facing the vehicle width direction of the forward-tilting cylinder engine is performed by starting the centrifugal clutch type start clutch 2 (one-way clutch 2 a) arranged on the right side of the crankshaft 1. Input pulley 3a of the V-belt continuously variable transmission 3 on the right outside through the
Conveyed to. At the left end of the crankshaft 1, a magnet 31 and a recoil starter 32, which are covered with a cover, are provided.

In the V-belt type continuously variable transmission 3, an output pulley 3b provided rearward is provided at a right end of a drive shaft 21 disposed rearward in parallel with the crankshaft 1, and the input pulley 3b is provided. The V-belt 3c is wound between the output pulley 3a and the output pulley 3b along a circulation path extending in the front-rear direction. The V-belt type continuously variable transmission is housed in a main transmission room 24 separately from the crankcase 22 and the sub gear transmission 4 housing room 23. The main transmission room 24 is provided with the engine cover 2 from the outside.
5, the mating surface substantially coincides with the center of the V-belt.

A sub-gear transmission 4 is provided at a position substantially in the center of the vehicle body on a drive shaft 21 disposed rearward in parallel with the crankshaft 1. 22 and is located behind and adjacent thereto. In the sub gear transmission 4, the drive shaft 2
1 and the countershaft 5 are positioned in parallel, and the gears provided on the respective gears are selected by the shift lever 26 to set the shift speed. An output shaft 8 is provided parallel to and behind the counter shaft 5 of the sub-gear transmission 4. A drive gear 6 is provided at one end (left end) of the counter shaft 5, and the output shaft 8 is connected to the output shaft 8. Driven gear 7
Is press-fitted and fixed. And drive gear 6
The driving force transmitted through the sub-gear transmission 4 is transmitted to the output shaft 8 by meshing with the driven gear 7 at one end of the output shaft 8. The output shaft 8 is supported on both sides by bearings 27 across the driven gear 7 press-fitting position. A speedometer gear 30 is provided outside the left bearing 27, and an end of the right bearing 27 is provided in the accommodation chamber 23. And the bevel gear 9 is fixed in the rotation direction.

Further, as shown in FIGS. 2 and 3, the right end of the output shaft 8 and the end of the propeller shaft 11 are located in the accommodation chamber 23, and the bevel gears 9, 10 are provided from the output shaft 8 through the bevel gears 9, 10. The rotation shaft is converted from the left-right direction to the front-rear direction, and transmitted to the propeller shaft 11 extending back and forth. In the propeller shaft 11, power is transmitted to a front axle 13 and a rear axle 13 (not shown) via differential gears (differential gears) 12 provided at front and rear ends, respectively. In FIG. 3, the front propeller shaft 11
, The front side is omitted, and the rear wheel 14 shows only the right side, and the left side is also symmetric with the right side. Further, the output side portion of the engine unit 20 of the propeller shaft 11 is connected by a universal joint.

As shown in FIG. 1, the central shaft hole 15 of the middle hub 7a of the driven gear 7 in the sub-gear transmission 4 is press-fitted to the outer peripheral surface of the output shaft 8. In the output shaft 8, a flange-shaped step 8a is formed on the right side of the hub 7a in FIG. 1 to prevent further press-fitting, and the driven gear 7 is fixed within a certain range on the outer peripheral surface of the output shaft 8. Can be pressed into any position. 1, a spacer 29 or another member is interposed between the hub 27 and the bearing 27 on the left side of the hub 7a.
In conjunction with a, the driven gear 7 is positioned on the output shaft. When a predetermined torque equal to or higher than the maximum output of the engine is applied to the press-fit margin indicated by reference numeral 28, slippage occurs in the press-fit portion, and when the torque is equal to or lower than the predetermined torque, the power is fitted without slipping so that power can be transmitted.

The portion where the shaft hole 15 of the driven gear 7 is press-fitted into the output shaft 8 transmits power normally within the output range of the engine. On the other hand, when a torque greater than the engine output is received due to a shock or the like, slippage occurs in the press-fitted portion, preventing overload and preventing damage to the power drive system.

[0018]

As described above, according to the present invention, since the shaft hole of the driven gear of the sub-gear transmission is press-fitted to the output shaft so as to slide with a predetermined torque or more, the engine output is reduced. Normally, when a shock exceeding the engine output is received, slippage occurs in the press-fitted portion, preventing overload, and preventing the power drive system from being damaged.

The entire engine case can be reduced in size and weight without increasing the number of parts in the drive system, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of an overload prevention device for an off-road vehicle according to an embodiment of the present invention.

FIG. 2 is a partially longitudinal plan view showing a portion from a crankshaft to a propeller shaft of the engine according to the embodiment.

FIG. 3 is a vertical cross-sectional view showing from the output shaft to the rear wheel of the engine according to the embodiment.

FIG. 4 is a reference side view showing an off-road vehicle.

FIG. 5 is a vertical cross-sectional view showing a conventional overload prevention device for an all-terrain vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crankshaft 2 Starting clutch 3 V-belt continuously variable transmission 4 Sub gear transmission 5 Counter shaft 6 Drive gear 7 Driven gear 8 Output shaft 11 Propeller shaft 13 Axle 15 Shaft hole 28 Press-fit allowance

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F16D 7/02 F16D 43/286 43/286 F16H 3/08 Z F16H 3/08 9/18 A 9/18 35/10 H35 / 10 F16D 1/06 CF term (reference) 3D039 AA02 AA04 AB21 AC34 AD23 3D043 AA06 AA07 AB17 EA03 EA14 EA36 EA42 EC03 EF19 3J028 EA30 EB33 EB35 EB44 EB62 FA21 FB06 FC32 FC38 FC02 FC07 AB02

Claims (3)

[Claims] A power transmission from an engine to an output shaft from a main transmission via a sub-gear transmission, wherein a shaft hole of a driven gear meshing with a drive gear of a counter shaft of the sub-gear transmission is formed on the output shaft. An overload prevention device for an uneven terrain traveling vehicle, wherein a press fit is set, and the press fit is set so that a slippage occurs between the driven gear and the output shaft at a predetermined torque or more. 2. The overload prevention device for an uneven terrain traveling vehicle according to claim 1, wherein the main transmission mechanism is a V-belt type continuously variable transmission provided with a starting clutch on an input side. 3. The overload prevention device for an uneven terrain vehicle according to claim 1, wherein four wheels are driven from an output shaft via a propeller shaft and front and rear axles.