JPS61285134A - Power transmission gear for vehicle - Google Patents

Abstract

PURPOSE:To reduce a turning radius by providing a primary differential gear between front and rear wheel differential gears so as to transmit power to said front and rear wheel differential gears, and providing a differential lock means which locks and releases said primary differential gear in accordance with the steering angle of a steering wheel. CONSTITUTION:A front wheel driving system 11 for driving front wheels 3, 4 has a front wheel differential gear 12 and final reduction gears 13, 14 provided on both right and left sides of the gear 12. A rear wheel driving system 15 for driving rear wheels 5, 6 has a rear wheel differential gear 16, final reduction gears 17, 18 provided on both sides of the gear 16, and brakes 19, 20. In this construction, a primary differential gear 21 is provided between the front and rear wheel differential gears 12, 16, to transmit power to the front and rear wheel differential gears 12, 16 via a pair of output shafts 22, 23 of the gear 21. A differential lock means 28 having a lock pin 26 which can be engaged and disengaged with a side gear 25 via a differential case 24, and a shifter 27 which supports the pin 26, is provided on the primary differential gear 21. And, the primary differential gear 21 is locked when the steered angle of front wheels is less than a set value.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a power transmission device for a vehicle.

(Prior Art) In a vehicle such as a four-wheel drive tractor, a differential is incorporated into each of the front wheel drive system and the rear wheel drive system, so that left and right differential functions can be obtained for both the front and rear wheels when turning.

(Problem to be solved by the invention) When considering the turning performance of a vehicle, it is better to increase the circumferential speed of the front wheels to about 2 degrees relative to the circumferential speed of the rear wheels to correspond to the difference in turning radius between the front and rear wheels. known to be desirable.

However, in the past, it was not possible to obtain a differential function between the front and rear wheels, so it was not possible to double the circumferential speed of the front wheels, and the current situation is that the circumferential speed of the front wheels is only increased by 1.03 to 1.04 times. It is.

Therefore, sufficient turning performance could not be obtained.

The present invention was provided for the purpose of solving such conventional problems.

(Means for Solving the Problems) In the present invention, as specific means for solving the above problems, the front wheel drive system 11 is provided with a front wheel differential 12, and the rear wheel drive system 15 is provided with a rear wheel differential 16. In the power transmission system of a vehicle, each of these differentials 12, 16 is connected between the front and rear wheel differentials 12, 16.
A driving differential 21 is provided to transmit power to the engine, and the driving differential 21 is locked and the steering handle 7 is rotated beyond a predetermined angle.
A differential lock means 28 is provided so as to be released when the lever is operated to the L position.

(Function) When the front wheel turning angle is within 10°, such as when traveling straight, the lock bin 26 of the differential lock means 28 engages the size 1 gear 25 via the differential case 24, and locks the driving differential 2I. Therefore, the drive differential 21 does not perform a differential function, and the front and rear wheel differentials 12. Transmits power evenly to +6. In other words, the output shafts 22 and 23 are directly connected, and the operation is the same as in the conventional case.

When the steering handle 7 is turned to a front wheel turning angle of 10 degrees or more, the valve 30 moves in the unlocking direction in conjunction with the operation, the cylinder 29 contracts, the lock pin 26 is pulled out from the side gear 25, and the drive differential is released. Unlock 21. Therefore, the driving differential 21 performs its original differential function and transmits power to the front wheel differential 12 and the rear wheel differential 16 according to their load conditions, so that the rotational speed of the front wheel differential 12 changes to the rear wheel differential. Because it is larger compared to the differential 16 side, it is a minor problem.
You can turn quickly and easily.

For example, when turning around point P as shown in FIG. The rear wheel differential 1 is set so that the left and right rear wheels 5 and 6 rotate at a circumferential speed ratio corresponding to
6 works, and on the front wheel 3.4 side, the front wheel differential 12 is set so that the left and right front wheels 3.4 rotate at a peripheral speed ratio corresponding to the turning radius R3 and R4 of the people from each front wheel 3.4 to the turning center P. ist
fh<. On the other hand, since the turning radii of the front wheels 3, 4 and the rear wheels 5.6 are also different, the driving differential 21 operates accordingly, causing the front wheels 3.4 to rotate faster than the rear wheels 5.6. Therefore, it is possible to turn with a small radius without difficulty.

(Example) Hereinafter, the present invention will be described in detail with reference to the illustrated example.
The figure illustrates a four-wheel drive tractor, in which 1 is a tractor body, an engine 2, and a pair of left and right front wheels 3.4 and rear wheels 5.
6. 7 is the steering handle, and tractor body 1.
The front wheels 3.4 are supported via a handle post 9 and the like to a steering box 8 attached to the steering wheel 2, and the front wheels 3.4 can be steered via a pitman arm 10.

No. 1M does not show a power transmission device to the front and rear wheels. The front wheel drive system 11 that drives the front wheels 3.4 includes a front wheel differential 12 and final reduction gears 13.14 provided on both left and right sides thereof. The rear wheel drive system 15 that drives the rear wheels 5 and 6 also has a rear wheel differential 1.
6 and a final reduction gear 17.18 provided on both sides thereof, and a brake 19 for braking each rear wheel 5.6.
．． 20 are provided. A driving differential 21 is provided between the front and rear wheel differentials 12.16, and transmits power to each of the front and rear wheel differentials 12.16 via its pair of output shafts 22.23. The drive differential 21 has a differential lock means 28 that includes a lock bin 26 that can be freely engaged with and detached from the side gear 25 via the differential case 24, and a shifter 27 that supports the lock bin 26. The shifter 27 is, for example, a cylinder 2
9, and its cylinder 29 is controlled by a valve 30. The valve 30 is interlocked with the handle 7, and when the front wheel turning angle is within 10 degrees, the driving differential 21 is activated.
When the differential is 10 degrees or more, it operates to unlock the driving differential 22. power differential 2
1 is driven by power transmitted from the engine 2 through a transmission ff 31 and a drive shaft 32.

Note that the differential lock means 28 may be of a disc type or the like instead of a bottle type. Further, the mechanism for interlocking the differential lock means 28 and the handle 7 may use a mechanical link or the like.

(Effects of the Invention) According to the present invention, by the action of the power differential 21, the front wheels 3
, 4 and the rear wheels 5, 6 can be driven at circumferential speeds corresponding to their turning radii. Therefore, it is possible to turn easily with a small radius, and the turning radius is significantly smaller than in the past. In addition, the driving differential 21 is unlocked when the steering handle 7 is operated at a predetermined angle or more, and is locked by the differential locking means 28 when the steering wheel 7 is operated at a predetermined angle or less.
There is no possibility that only the wheels 3 and 4 or the rear wheels 5 and 6 rotate.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, with FIG. 1 being a configuration diagram of the main parts, FIG. 2 being a side view, and FIG. 3 being an explanatory diagram of the operation. 3, 4...Front wheels, 5, 6...Rear wheels, 7...Steering handle, 11...Front wheel drive system, 12...Front wheel differential,
15...1 multi-wheel drive system, 16...rear wheel differential, 21...
...Motive differential, 28...Differential locking means.

Claims (1)

[Claims] 1. In a power transmission system for a vehicle in which the front wheel drive system 11 is provided with a front wheel differential 12 and the rear wheel drive system 15 is provided with a rear wheel differential 16, each of these differentials 12, 16 is provided between the front and rear wheel differentials 12, 16.
A vehicle characterized in that a driving differential 21 is provided to transmit power to the vehicle, and a differential locking means 28 is provided to lock the driving differential 21 and release it when the steering handle 7 is operated at a predetermined angle or more. Power transmission device.