JPS6229255B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to a sport or recreational vehicle that can be driven off-road, and more specifically to a vehicle that is equipped with a differential limiting device and has excellent maneuverability, including starting and stopping, when traveling on rough terrain. Regarding vehicles.

Over the past 10 years, cars that can drive not only on asphalt roads but also on rough terrain, ice and snow have become very popular. A typical example of such a vehicle to which the present invention is applied is the Tri-Moto (trademark) tricycle manufactured and sold by Yamaha Motor Co., Ltd. in Japan. The tricycle has a frame with a front fork that has a relatively large diameter inflatable balloon.
Supports tires (low pressure tires). This balloon tire can be steered by a handlebar. The two rear wheels are supported on a common axle, to which is attached a sprocket, which is also chain-driven by a prime mover mounted on the frame.

The above-mentioned conventional tricycle has a problem when turning. In other words, balloon tires have a very high slip resistance with the road surface, making it difficult to turn, especially when driving at low speeds, and drivers must learn to properly lean the vehicle toward the outer wheels when attempting to turn. I have to stay there. Inexperienced drivers tend to lean toward the inside wheels, but leaning inward has no effect and actually makes turning more difficult. As a result, there was a problem that the tires wore out faster and the road surface was damaged.

One solution to these problems is to replace the fixed single axle configuration with a two axle configuration and connect the two axles with a known differential. When turning using this known differential device, the inner and outer wheels can rotate at different speeds, making the turning operation easier. However, another problem arises in such off-road vehicles that conventional differentials make their use impractical. That is, as is well known in this technical field, when two axles are connected using a conventional differential, when one wheel spins, as occurs when driving in icy, snowy or sandy areas, the other wheel Lose indexing power. As a result, the vehicle was prone to getting stuck in mud.

Therefore, there is a vehicle in which the two axles are connected using a dual mode differential device. In this case, when driving on dry or hard surfaces, the device functions as a normal differential and facilitates steering and turning movements. When this tricycle gets stuck in mud or snow, the driver turns off the engine, gets out of the vehicle, uses a special wrench for this differential, and locks the two axles, which causes only one differential to lock. It functions as an axle for the vehicle and provides the desired torque to the wheels to help the vehicle get out of the mud. However, it was troublesome to have to get out of the car and do this work each time.

The present invention was made in view of these circumstances, and despite using balloon tires with high slip resistance for the pair of left and right rear driving wheels,
Reliably transmits driving force to the rear wheels under various road conditions,
An object of the present invention is to provide a vehicle for running on rough terrain that can secure traction force and improve turning maneuverability.

To achieve this objective, the present invention uses a differential device that automatically cuts off the transmission of driving force to the high-speed rear wheel of a pair of rear wheels. That is, the present invention comprises a pair of left and right driving rear wheels equipped with balloon tires, a longitudinally long driver's seat disposed between the two rear wheels, and a prime mover disposed below the driver's seat. In a rough terrain vehicle that transmits the driving force of the prime mover to the rear wheels via a differential device, the differential device includes:
a housing rotatably held on the vehicle body frame and rotated by the prime mover; a pair of slide gears held slidably in the axial direction on each rear axle and transmitting rotation of the housing to each rear axle; and a pair of sliding gears between each rear axle. and a cam ring that slides the slide gear at a certain level due to a difference in rotational speed. When a difference in rotational speed occurs between the two rear axles, the slide gear on the high-speed side rear axle is pushed by the cam ring and released from the housing, and the high speed is removed from the prime mover. It is configured to cut off the transmission of driving force to the side rear axle.

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

FIG. 1 is a side view of a typical three-wheel vehicle for traveling on rough terrain according to the present invention, FIG. 2 is a rear view, and FIG. 3 is a sectional view of the differential gear according to the present embodiment.

First, in FIG. 1, reference numeral 10 indicates a tricycle for traveling on rough terrain to which the present invention is applied. The tricycle has relatively large diameter, wide, low pressure balloon tires on each of its three wheels. The front wheel 12 is rotatably attached to a front fork 14, and the front fork 14 is held by a neck 16 of the frame so as to be rotatable left and right. The handlebar 18 is fixed to the front fork 14, so that the front wheel 12 can rotate about a substantially vertical axis.

As will be described in detail later when explaining Figure 3,
The two rear wheels 20, 20' are bolted or fixed to mutually independent rear axles 22, 22', and these rear axles 22, 22' are mounted on a frame-mounted torque transfer type differential. They are connected to each other via a moving device 24.

The frame also holds a prime mover (not shown). This prime mover is usually an internal combustion engine. This engine is usually arranged under a driver's seat 26 which is long in the longitudinal direction and is arranged between both rear wheels. The front fender 28 covers the front wheel 12, and the rear fenders 30, 30' cover the rear wheels 20, 20', respectively. Usually, a chain drive mechanism is used to connect the prime mover to the rear wheels via a differential, the details of which will be described later.

Since the present invention mainly relates to a differential device used to connect a prime mover to a rear wheel,
It is not deemed necessary to describe the general structural features of the rough terrain tricycle of FIG. 1 in further detail.

A cross-sectional view of a torque transfer type differential designed for use with the rough terrain tricycle of FIG. 1 is shown in FIG. This differential is designated generally at 24. The device 24 is generally symmetrical about a central plane indicated by a vertical line 26. Therefore, in the following description, descriptions of one of the symmetrical elements also apply as far as possible to the other element. The device 24 includes a first (left) housing 28 and a second (right) housing 28'. One end of these two housings 28, 28' becomes an annular flange part 30, 30', and these flange parts 30, 30' form a center unit (spider) of the torque transfer differential 24.
It is fastened to two opposing surfaces of 32 with bolts 34. That is, this bolt 34 passes through a bolt hole located on a straight line in the flange portions 30, 30' and the center unit (spider) 32.

A left rear axle 22 is disposed within the first (left) housing 28 . That is, a predetermined portion of the entire length of the first housing 28 is formed into a substantially cylindrical shape, and the rear axle 22 is coaxially disposed in this substantially cylindrical portion. A suitable bushing 3 is provided between the outer circumferential surface of the left rear axle 22 and the inner circumferential surface of the housing 28.
5, 36 are provided, and the rear axle 22 is rotatably supported within this housing 28. Lubricating oil is applied to the bushes 35 and 36, and an end seal 38 is installed between the housing 28 and the rear axle 22 to prevent dust and foreign matter from being applied to these bushes 3.
It prevents damage to 5 and 36.

The first and second housings 28, 28' are suspended from the vehicle body frame 42 and configured to be rotationally driven by a prime mover. That is, an annular bearing housing 40 is fixed to a vehicle body frame 42 by bolts 44. First housing 2
8 passes through the center hole of the bearing housing 40, and an axle support bearing 45 is disposed between the two. The seal members 46 and 48 are the bearing 4
5 lubricating oil is held in place.

Splined to the outer periphery of the first housing 28 is a sprocket support member 50;
Sprocket 5 is bolted to this
It is 2. A plurality of teeth are formed at predetermined intervals on the outer periphery of the sprocket 52, and these teeth engage with a drive chain (not shown) that connects the prime mover and the differential.

It will be appreciated from the above that as sprocket 52 rotates, first and second housings 28, 28' also rotate relative to body frame 42, with bearing 45 providing smooth rolling contact therebetween.

Since a spline connection is also used to attach the braking device, in this embodiment a disc brake, to the second housing 28', the disc plate 54 also rotates together with the second housing 28'. As in the case of known disc brakes,
Caliper-shaped friction means (not shown) are arranged to clamp the disk plate 54. Instead of this disc brake, it is also possible to use a drum brake. In any case, the differential device 24 shown in FIG. 3 requires only one brake device, which can apply braking force to both rear wheels when in use. As is well known, conventional differentially connected axles require one brake device per axle.

Next, the differential device 24 will be explained. FIG. 4 shows the internal mechanism with the housings 28, 29' removed, and FIG. 5 shows the spider 32, slide gear 56,
6 is a diagram showing the operation of the cam ring 62 and the clutch rings 60, 60', and FIG. 7 is an explanatory diagram showing the relative positions of each part.

As shown in FIGS. 3, 4, and 5, the torque transfer type differential device 24 has left and right slide gears 5.
6,56'. The sliding gears 56, 56' are formed with splines 58, 58', and these sliding gears 56, 56' are connected to the rear axle 2 with respect to cooperating driven clutch rings 60, 60'.
2, 22' can be displaced by a predetermined amount in the axial direction. The spider 32 has tooth-like protrusions 61, 61' formed uniformly and radially on both sides thereof, and these are recessed parts 61a, 6 formed oppositely on the sides of the slide gears 56, 56'.
It meshes with 1a'. As is clear from FIGS. 4 and 5, the tooth-like protrusions 61 and 61' are formed in a rectangular plane shape, while the recesses 61a and 61a' are shaped like the tooth-like protrusions 6.
Wider than the tooth width of 1,61'.

62 is a cam ring. The cam ring 62 is disposed in the central hole of the spider 32 and includes a plurality of index pins 64 that engage with the inner peripheral surface of the spider 32. The index pin 64 has a slight play in the rotational direction (x in Fig. 7) in the cam ring 62.
) is transmitted to the cam ring 62 while allowing the rotation of the spider 32 to be transmitted to the cam ring 62. As shown in FIG. 6, cams 62a and 62a' each having a substantially trapezoidal shape in plan are formed on both left and right side surfaces of the cam ring 62. As shown in FIG. On the other hand, driven clutch ring 60,6
0' are formed with approximately trapezoidal cam grooves 60a, 60a' that engage with the cams 62a, 62a'.
The clutch rings 60, 60' are fixed to the sliding gears 56, 56'.

The slide gears 56, 56' are pressed toward the spider 32 by lock mechanism return springs 66, 66'. the clutch ring 60;
60' is fixed to the slide gears 56, 56', and the cam grooves 60a, 60a' are pressed against the cams 62a, 62a' by the spring force of the springs 66, 66', and when these are engaged, the slide gears The tooth-like protrusions 61, 61' of the spider 32 engage with the recesses 61a, 61a' of the spiders 56, 56' (see the right side portions of FIGS. 5 and 6).

2 arranged at the ends of the two rear axles 22, 22'
The snap rings 70, 70' have the function of preventing the slide gears 56, 56' from falling off due to the spring force of the return springs 66, 66', and facilitating assembly. Furthermore, the axle support bearing 7
2, 72', the rear axle 22, 22' is the bush 35,
The axle thrust pin 73, which is properly supported for free rotation within the housing 28, 36 and is centrally located between the bearings 72, 72',
The amount of movement of the axles 22, 22' is limited within the limits of 28'.

Next, the operation of this differential device 24 will be explained. First, during power running, the rotation of the prime mover is transmitted to the sprocket 52 by the drive chain, causing the housings 28, 28' to rotate. Housing 28,2
The spider 32 also rotates together with 8'. The cam ring 62 attached to the center hole of this spider 32 also rotates in the same manner. On the other hand, slide gears 56, 56'
is pressed toward the spider 32 by springs 66, 66'. When the car is stopped, the left and right rear wheels 2
When 0 and 20' rotate at a constant speed, the cam groove 60
The cams 62a, 62a' engage in the recesses 61a, 60a', and the toothed protrusions 61, 61' engage in the recesses 61a, 61a.
It is involved in a′. As a result, the rotation of the spider 32 is caused by the engagement of the toothed protrusions 61, 61' and the recesses 61a, 61a', causing the rear axles 22, 22' and the rear wheels to rotate.
0,20'.

When turning, etc., a difference in rotational speed occurs between the rear wheels 20 and 20'. For example, when turning right, the left rear wheel 20 rotates faster than the other wheel 20'. Therefore, the recess 61 of the left slide gear 56
a moves forward relative to the protrusion 61 of the spider 32, and at this time, the slope of the groove 60a of the clutch ring 60 rides on the cam 62a of the cam ring 62. Therefore, the clutch ring 60 and the slide gear 56 resist the spring force of the spring 66 to
7. Move to the left in Figure 7, and remove the groove 61a and the tooth-like protrusion 6.
1 is disengaged. That is, the driving force of the prime mover is transmitted to the low-speed right rear wheel 20', and the high-speed left rear wheel 20 spins idly.

FIG. 7a shows the relative positions of the various parts during the above-mentioned power running, and F in the figure shows the rotational speed and direction of the spider 32 and the cam ring 62.

During braking, the cam ring 62 rotates together with the spider 32 with a slight phase shift relative to the spider 32 due to the action of the index pin 64. That is, FIG. 7b shows the relative positions of each part during braking, in which B indicates the direction of the braking force, and X indicates the amount of phase change between the cam ring 62 and the spider 32. The braking force is transmitted from the toothed projections 61, 61' of the spider 32 to the recesses 61a, 61a' of the slide gears 56, 56'. The right part of FIG. 7b shows this state. When lightly braking when turning to the left, the left rear wheel 2
0 is delayed compared to the right rear wheel 20'. Therefore, the slope of the cam groove 60a of the left clutch ring 60 rides on the cam 62a of the cam ring 62, and the engagement between the toothed projection 61 and the recess 61a is released. Therefore, the braking force is not transmitted to the left rear wheel 20, but the braking force is reliably generated to the right rear wheel 20'. This phenomenon is the same even when light braking is applied before turning. Note that when braking is applied strongly, no rotational speed difference occurs between the two wheels, and therefore braking force is reliably generated on both wheels regardless of whether or not the vehicle is turning.

According to the differential device described above, driving force can be transmitted to both rear wheels while generating a difference in rotational speed between the two rear wheels when turning or when road conditions require it. Further, according to this differential device, when one rear wheel completely loses traction force, most of the drive torque is transmitted to the other rear wheel. When turning, the outside rear wheel must rotate faster than the inside rear wheel.
Otherwise, the tires will wear out severely. During such a turn, the sliding gear on the outer rear wheel side, which rotates at high speed, is disengaged from the spider 32 by the cam ring and clutch ring against the return spring. As a result, the outside rear wheel spins until the end of the turn. When the turning is completed, the return spring forcibly engages the slide gear with the spider 32 again, and the driving force is again transmitted to the outer rear wheels.

When driving this vehicle on rough terrain where one wheel is lifted off the ground, or on snow or ice where one wheel loses traction or spins faster than the other,
All torque is transferred to the wheels rotating at low speed. Furthermore, under such conditions, when braking is performed by applying frictional force to the single brake disc 54, 100% of the braking force is applied to the wheel on the high speed side, and both wheels are rotating at the same speed. Sometimes the braking force is evenly distributed to both wheels.

Note that the effects of the present invention will be even more remarkable when considering the fact that in a tricycle, one rear wheel is particularly likely to lift off the road surface when turning or the like.

As described above, the present invention provides a braking device between the prime mover and the differential, and includes a mechanism in the differential that cuts off the transmission of driving force to the high-speed rear axle when a rotational speed difference occurs between the rear axles. It was established. Therefore, using this differential to connect the two rear axles allows more torque or drive power to be transmitted to the wheel that is rotating at a lower rotational speed. As a result, when turning, most of the drive torque is transmitted to the inner wheel, and the outer wheel is free to rotate at a speed determined by the vehicle speed and at the corresponding turning radius. If the vehicle encounters soft or icy ground,
When a torque transfer differential is used, if one wheel begins to spin, all of the drive torque is automatically transferred to the wheel rotating at a lower angular velocity. In this way, the driving force is automatically transmitted to one wheel, the other wheel, or both, depending on whether the two wheels are rotating at different speeds or at the same speed. Since this torque transfer type differential is associated with the braking system of a vehicle, the use of this device is indeed advantageous. If a conventional differential is used, drum brakes or disc brakes must be installed on both axles to stop the vehicle without being pulled to one side. However, when the torque transfer type differential device of the present invention is used, a single braking device is sufficient, which is suitable for simplifying the structure and reducing the number of parts. When a braking device is installed, braking force is applied uniformly to both wheels if they are rotating at the same speed, and to the wheel on the faster rotating side if they are rotating at different speeds. In this way, when the rotational speeds of both wheels are balanced, the braking force is evenly distributed between the two wheels.

[Brief explanation of the drawing]

Figure 1 is a side view showing one embodiment of the present invention, Figure 2 is a side view showing one embodiment of the present invention;
The figure is a rear view, FIG. 3 is a sectional view of the differential limiting device, FIG. 4 is a diagram showing the internal mechanism of the differential control device with the housing removed, and FIG. 5 is a diagram showing the operation of the spider and slide gear. FIG. 6 is a diagram showing the operation of the cam ring and clutch ring, and FIG. 7 is a diagram showing the relative positions of each part. 10... Vehicle, 20, 20'... Rear wheel, 22,
22'... Rear axle, 24... Differential gear, 28,2
8'...Housing, 32...Spider, 42...
...Body frame, 54...Brake disc, 5
6, 56'...Slide gear, 60, 60'...Driven clutch ring, 62...Cam ring.

Claims (1)

[Scope of Claims] 1. A pair of left and right driving rear wheels equipped with balloon tires, a longitudinally long driver's seat disposed between the two rear wheels, and a prime mover disposed below the driver's seat. A vehicle for driving on rough terrain that transmits the driving force of a prime mover to the rear wheels via a differential device, wherein the differential device includes a housing rotatably held on a vehicle body frame and rotated by the prime mover; a pair of slide gears that are held slidably in the axial direction on the axle and transmit the rotation of the housing to each rear axle; and a cam ring that slides one of the slide gears based on the difference in rotational speed between the rear axles. When a rotational speed difference occurs between the axles, the slide gear of the high-speed rear axle is pushed by the cam ring and released from the housing, cutting off the transmission of driving force from the prime mover to the high-speed rear axle. A vehicle for traveling on rough terrain.