JPH10181362A - Four-wheel drive mechanism of traveling vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To differentially drive front/rear, lift/right wheels in a simple structure, in a four-wheel drive type traveling vehicle. SOLUTION: The power transmitted to an input gear 12a of a first differential gear device 12 from the output power of an engine E is transmitted to a pair of output shafts 13 and 14 of this first differential gear device 12. Then, a first hydraulic pump 15 connected to the one output shaft 13 is connected to each of hydraulic motors 17 and 17 driving a pair of driving wheels 1 and 1, and transmit the power from the other output shaft 14 of the first differential gear device 12 to another pair of driving wheels 2 and 2 via an input gear 21a of a second differential gear device 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission structure for transmitting power to a front wheel and a rear wheel without slipping in a traveling vehicle driven by four-wheel drive.

[0002]

2. Description of the Related Art Conventionally, by transmitting power from an engine to a front wheel and a rear wheel differential of a four-wheel drive vehicle via a center differential, an unbalanced running that occurs on the front wheels and the rear wheels. In order to suppress the resistance and distribute the power to the other wheel when one of the wheels slips or idles, for example, as disclosed in JP-A-51-27234, a center differential device is used. The front wheels and the rear wheels are connected to each other by a propeller shaft or the like.

[0003]

However, in the conventional configuration, a buffer mechanism, a steering mechanism, and the like are disposed in a space between the center differential and the front and rear wheel differentials. When the connection is made by the propeller shaft or the like, it is necessary to provide a space for these, so that the entire vehicle has to be enlarged accordingly.
Also, when changing the specifications of a two-wheel drive vehicle to a four-wheel drive vehicle, it is necessary to make significant changes to these shock absorbing mechanism, steering mechanism, vehicle body, and the like. Therefore, it is necessary to secure a space for disposing the shock absorbing mechanism and the steering mechanism between the front wheel and the rear wheel, and in the front wheel supporting portion and the rear wheel supporting portion.

[0004]

Accordingly, the present invention uses the following means in order to solve such a problem. First, in a traveling vehicle having at least four drive wheels, the power transmitted from the output of the engine to the input gear of the first differential is transmitted to a pair of output shafts of the first differential. A first hydraulic pump connected to the output shaft of the first differential device is connected to each of the hydraulic motors driving a pair of drive wheels, and the power from the other output shaft of the first differential device is applied to the second differential motor. It is configured to be transmitted to another pair of drive wheels via the input gear of the device. In addition, it is also possible to transmit the power from the other output shaft of the first differential device to each of the hydraulic motors driving the other pair of drive wheels via the second fixed pump. is there.

[0005]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a four-wheel drive vehicle,
FIG. 2 is a diagram showing a four-wheel drive configuration of the present invention, and FIG. 3 is a diagram showing another embodiment of the present invention.

First, an embodiment of a transport vehicle A provided with a power transmission structure by four-wheel drive will be described. In FIG. 1, a front wheel 1.1 and a rear wheel 2.2 are arranged in front and rear portions of a transport vehicle A, and an operation unit 3 is arranged in an upper front part of the fuselage. A front column 4 to which an instrument panel is attached is erected on the operation unit 3, and a steering handle 5 is provided above the front column 4,
A driver's seat 6 is arranged behind the steering handle 5. In addition, a loading bed 7 for dumping by the expansion and contraction of a hydraulic cylinder (not shown) is arranged behind the operation unit 3.

Next, the power transmission configuration of the transport vehicle A will be described with reference to FIG. An engine E is mounted below the driving section 3. A drive-side split pulley of the belt-type continuously variable transmission 10 is disposed on the output shaft of the engine E, and power is transmitted from the drive-side split pulley to the driven-side split pulley via a belt to change the pulley width. By doing so, the speed changes continuously. A gear 11 is fixed to a transmission shaft 30 supporting the driven split pulley, and the gear 11 meshes with an input gear 12a of the first differential device 12 to transmit power. In the first differential device 12, two pairs of a differential pinion and a differential side gear that mesh with each other are rotatably arranged in a differential case. 13.1
4 are differentially coupled.

A hydraulic pump 15 is arranged on the side of the first differential device 12, and the other end of the output shaft 13 on one side is connected to the pump shaft. Hydraulic pipes 16 are connected to the suction side and the discharge side of the hydraulic pump 15, respectively, and are connected in parallel with hydraulic motors 17 driving the front wheels 1.1. Make up. The hydraulic motor 17 includes left and right front wheels 1.1
And the output shafts of the hydraulic motors 17 are connected to the drive shaft 18 of the front wheels. The hydraulic pipe 1
6. The right and left hydraulic motors 17
Are connected to form a closed circuit, so the left and right front wheels 1
In the case where one of the loads becomes large or a rotation difference occurs at the time of turning, differential rotation is permitted.
The hydraulic pump 15 is a fixed displacement type pump, and discharges a fixed amount of pressure oil for driving the front wheel 1 in accordance with the rotation speed of the rear wheel 2 when the vehicle is traveling straight.

On the other hand, a gear 20 is disposed on the other of the output shaft 14 protruding from the first differential device 12, that is, on the side for transmitting power to the rear wheel in this case. Engages with the input gear 21a of the second differential 21 to transmit power. The second differential device 21 has substantially the same configuration as the first differential device 12, and differentially couples a pair of left and right rear drive shafts 22. Rear wheels 2.2 are mounted on both ends of the drive shafts 22.

As described above, the power from the first differential device 12 is transmitted to the hydraulic motors 17 of the front wheels 1.1 having the steering mechanism via the deformable hydraulic pipes 16. Therefore, it is not necessary to provide a differential device in the front axle case, or to provide a space or a transmission mechanism for driving the front wheels 1 from the differential device. Then, the rear wheels drive the rear wheels 2 via the second differential device 21 and the like, so that the rear wheels travel by four-wheel drive. Then, when a rotation difference occurs between the front wheel 1.1 and the rear wheel 2.2, for example, during a sharp turn, a difference in rotation speed occurs between the front wheel 1.1 and the rear wheel 2.2. The first differential 12 is actuated to optimally distribute power to the front wheels 1.1 and the rear wheels 2.2, and the rear wheels 2.2
1, the front wheels 1.1 are connected in parallel with the hydraulic motors 17 so that hydraulic pressure is equally applied to the left and right, the flow rate increases on the side with a small load, and the rotation speed on the outside of the turn And the vehicle can turn smoothly without slipping.

FIG. 3 shows a configuration for transmitting the driving force to the rear wheels 2. That is, a hydraulic pump 25 is interlockingly connected to the output shaft 14 for driving the rear wheels, which protrudes from the first differential device 12, instead of the gear 20, and a hydraulic pipe 2 is connected to the discharge side and the suction side of the hydraulic pump 25.
6 and 26, and the other ends of the hydraulic pipes 26 and 26 are connected in parallel to hydraulic motors 27 and 27 that drive the left and right rear wheels 2 and 2 to form a closed circuit. Make up the device. Therefore, there is no need to dispose a differential device on the rear wheels 2 side, and differential is allowed by a closed circuit connected in parallel. And the first differential device 1
Hydraulic pumps 15 and 25 of the same fixed displacement type are disposed on output shafts 13 and 14 protruding on both left and right sides of the hydraulic pump 2.
6 and hydraulic motors 17 and 27 disposed on the traveling shafts of the front wheels 1.1 and the rear wheels
・ Send oil to hydraulic motors 17 and 27 from 25
-As a configuration for driving 1 and the rear wheels 2, 2, the power transmission mechanism has a simple configuration without a propeller shaft or a differential gear device.

As described above, the one-wheel, two-motor type hydraulic drive unit is connected to the output shaft 14 for driving the rear wheels.
, A four-wheel drive device including a two-pump four-motor type hydraulic drive device is combined with a front wheel drive hydraulic drive device, and a rotational difference is generated between the front wheels 1.1 and the rear wheels 2.2. In this case, for example, at the time of a sharp turn, the driving force is optimally distributed to the hydraulic pump 15 and the hydraulic pump 25 by the first differential device 12. As in the case of the differential drive of the front wheels, the front wheels 1.1 are connected in parallel with the hydraulic motors 17 and the rear wheels 2.2 are connected in parallel with the hydraulic motors 27, so that the left and right sides are evenly distributed. Hydraulic pressure is applied, the flow rate on the side with a small load increases, the rotation speed on the outside of the turn increases, and turning can be performed smoothly without slipping.

[0013]

The following effects can be obtained by the above configuration. First, in a traveling vehicle having at least four drive wheels, power transmitted from an engine output to an input gear of a first differential device is transmitted to a pair of the first differential device. The first hydraulic pump connected to one of the output shafts is connected to each of the hydraulic motors driving a pair of drive wheels, so that the propeller shaft, axle case, differential, etc. Since it is not necessary to dispose the power transmission mechanism, the configuration can be simplified, and the arrangement of the steering mechanism, the suspension mechanism for supporting the drive wheels, and the like is not restricted, and the vehicle can be downsized. .

According to a second aspect of the present invention, power from the other output shaft of the first differential is transmitted to another pair of drive wheels via an input gear of the second differential. As a result, when the distributed power is transmitted to the second differential, and the second differential is used for the rear wheels, for example, when turning, the front wheels and the rear wheels , The rotational speed of the front wheels increases, and the rotational speed of the outer wheels increases, so that the front wheels and the rear wheels are differentially driven to enable smooth turning. Therefore, even when one of the front and rear drive wheels is driven using a hydraulic motor that is advantageous in terms of space, the vehicle can be driven by four-wheel drive corresponding to the front and rear power difference.

According to a third aspect of the present invention, the power from the other output shaft of the first differential is supplied to each of the hydraulic motors driving the other pair of drive wheels via the second hydraulic pump. As it is transmitted, the power is distributed optimally to the front and back by a single mechanical differential, and the power distributed to the front and back drives one set of hydraulic motors each, and the four wheels can be driven reliably. It became so. In addition, by using a drive mechanism by a hydraulic motor for all the drive wheels instead of one side of the front and rear wheels, there is no need to dispose a propeller shaft and axle case for transmitting power to the front and rear wheels. Since it is possible to eliminate a differential device for differentially driving wheels of the vehicle, a space for disposing a shock absorbing mechanism such as a suspension is not limited, and the size of a vehicle can be reduced.
In that portion, the space such as the driving section and the loading platform can be widened.

[Brief description of the drawings]

FIG. 1 is a perspective view of a four-wheel drive vehicle.

FIG. 2 is a diagram showing a four-wheel drive configuration of the present invention.

FIG. 3 is a view showing another embodiment.

[Explanation of symbols]

 Reference Signs List A Truck E Engine 1 Front wheel 2 Rear wheel 12 Differential device 12a Input gear 13 Output shaft 14 Output shaft 15 Hydraulic pump 17 Hydraulic motor 21 Differential device 21a Input gear 22 Drive shaft 25 Hydraulic pump 27 Hydraulic motor

Claims (3)

[Claims] In a traveling vehicle having at least four drive wheels, power transmitted from an output of an engine to an input gear of a first differential is transmitted to a pair of output shafts of the first differential. And a first hydraulic pump connected to one of the output shafts is connected to each hydraulic motor driving a pair of drive wheels. 2. The traveling device for a traveling vehicle according to claim 1, wherein power from the other output shaft of the first differential device is transmitted to another pair of the output shafts via an input gear of the second differential device. A four-wheel drive mechanism for a traveling vehicle, wherein the four-wheel drive mechanism is transmitted to the first drive wheel. 3. The traveling device for a traveling vehicle according to claim 1, wherein the power from the other output shaft of the first differential drives another pair of driving wheels via a second hydraulic pump. A four-wheel drive mechanism for a traveling vehicle, which is transmitted to each hydraulic motor to be driven.