KR100620788B1 - Steering and Driving System of Industrial Vehicle - Google Patents

Abstract

The present invention relates to an industrial vehicle, and more particularly, a steering device having a drive chain and a sprocket driven by a steering cylinder, and a differential driving device having a simple configuration, wherein the front and rear wheels are steered in the same direction without restricting the steering angle. The present invention relates to a steering and driving system of an industrial vehicle in which differential driving of left and right wheels is effectively performed so that a vehicle traveling direction can be easily changed.

The steering and driving system of an industrial vehicle according to the present invention includes a steering cylinder and a front and rear steering cases respectively installed in front and rear of the vehicle body, including left and right sprockets and left and right pivots driven by a drive chain connected to both ends of the steering cylinder and the steering cylinder. A rotary valve connected to the steering pump and the hydraulic tank to discharge the hydraulic oil from the steering pump according to the rotation of the steering wheel, a first flow path connecting the front wheel steering case and the rear wheel steering case, and the rotary valve and the front and rear wheel steering. It includes a steering device for steering the front and rear wheels, including the second and third flow path for connecting the case, and a differential drive device for driving the left and right wheels differentially according to the resistance applied to the wheels connected to the driving pump. .

Chain, sprocket, differential, four-wheel steering, four wheel steering, differential

Description

Steering and driving system for industrial vehicle

1 is a schematic view of a working state of a conventional industrial vehicle.

2 is a perspective view of an industrial vehicle having a steering and drive system according to an embodiment of the present invention.

3 is a schematic view of a steering apparatus according to an embodiment of the present invention.

4A is a schematic diagram of a steering case included in the steering apparatus of FIG. 3.

Figure 4b is an operating state of the steering case when the left turn of the steering device of Figure 4a.

Figure 4c is an operating state of the steering case when the right turn of the steering device of Figure 4a.

5 is a front view of the driving device viewed from the line A-A of FIG.

6 is a schematic view of a steering apparatus according to another embodiment of the present invention.

7 is an operation state in which the industrial vehicle according to an embodiment of the present invention loads the object to the work machine.

8 is an operating state diagram in which the industrial vehicle of FIG. 7 rotates to lay down an object.

* Explanation of symbols for main parts of the drawings

1: industrial vehicle 130: rotary valve

2,3: Upper and lower frame 131: Steering wheel

20f, 20r: Front and rear wheels 132: Steering pump

21a, 22a: Left wheel 133: Hydraulic tank

21b, 22b: Right wheel 140a: Left channel

30: boom assembly 140b: right flow path

31: work machine 141a, 141b: solenoid valve

100,200: steering device 140,240: first flow path

110,120: Front and rear steering wheel 150,250: Second flow path

112,122: steering cylinder 160,260: third flow path

111a, 121a: Left input port 300: Differential drive device

111b, 121b: Right input port 310a, 310b: Left / right drive hydraulic motor

121: oil pressure chamber 320: gear case

122a: Piston 321: Drive Gear

122b: Set screw 322: Driven gear

123: drive chain 323: axle

124a, 124b: left / right sprocket 324: reduction gear train

125: housing 325: rotation axis

125a, 125b: left and right pivot 340: drive pump

130a, 130b: Left and right cylinder port

The present invention relates to an industrial vehicle, and more particularly, a steering device having a drive chain and a sprocket driven by a steering cylinder, and a differential driving device having a simple configuration, wherein the front and rear wheels are steered in the same direction without restricting the steering angle. The present invention relates to a steering and driving system for an industrial vehicle in which differential driving of left and right wheels is effectively performed.

In general, an industrial vehicle is a vehicle used for moving a powdery body such as soil or sand in a narrow space or for loading an object to a high place, and refers to a heavy equipment vehicle such as a skid steer loader or a forklift truck.

In such an industrial vehicle, front and rear wheels are installed at the front and rear of the lower side of the vehicle body, and a boom assembly to which a work machine such as a bucket and a fork is mounted is installed at the upper side of the vehicle body to perform work.

1 shows a schematic view of a working state of a conventional industrial vehicle.

In order for the industrial vehicle 11 to move the object 10 from the original place C to the new loading place E, at the place C, the object 10 is loaded in the work machine 12 of the vehicle 11 and then moved in the direction D. After reversing the vehicle, the vehicle 11 is advanced to the place E to go through the work sequence of lowering the object 10. Therefore, unnecessary operation such as having to move the vehicle forward and backward is required, which leads to an increase in working time.

In addition, when a conventional industrial vehicle unloads an object, a sufficient space for the vehicle to rotate may be secured. In many industrial sites and stores, it is often impossible to secure a space for the vehicle to rotate. . As shown in the drawing, when the wall surface 13 is formed at the place D, the vehicle 11 cannot move backward in the place D direction and thus cannot perform operations such as moving the object 10. There is an urgent need for the technology of an industrial vehicle that can smoothly perform the operation.

In order to perform the work effectively even in a narrow space, the steering system of the industrial vehicle may adopt a four-wheel steering system.In contrast to the two-wheel steering system that steers only the front wheel or the rear wheel, the rapid rotation of the vehicle is difficult in a narrow space. Has the possible advantages.

As a technique related to a four-wheel steering device, Korean Patent Application Publication Nos. 1999-41376 and 1998-45500 disclose a steering device for steering a front wheel and a rear wheel in opposite directions. In the conventional four-wheel steering system, front and rear axles, in which wheels are mounted on both sides, are installed in front and rear of the vehicle body, and front and rear steering cylinders are installed to form a predetermined interval with the front and rear axles, and both sides of the front and rear wheel steering cylinders. The tie rod and the knuckle arm are connected to each other so that the front and rear wheels are steered left and right as hydraulic pressure is supplied to the steering cylinder.

However, even with this configuration, since the steering angle of the wheel is limited to the moving distance of the steering cylinder, in order to change the traveling direction of the vehicle, a sufficient rotation space for moving the vehicle forward and backward is required. There was a problem.

In addition, Korean Patent No. 4310 discloses a technology that allows each wheel to rotate 360 ° in any direction by independent operation, so that the vehicle can be easily parked even in a narrow space. On the upper side of the wheel, a worm is coupled between two worm gears respectively driven by two stepping motors, and the worm is fixed to the steering shaft of the wheel so that each wheel is steered independently. However, in order to steer each wheel, a complicated configuration requiring a stepping motor, a gear train, and the like has a problem in that manufacturing cost is increased.

In addition, the conventional industrial vehicle is equipped with a differential drive device for driving the left and right wheels differentially in order to drive the vehicle effectively, most of the configuration of the differential drive device has a problem that the number of parts required and manufacturing cost increases. .

The present invention has been made to solve the above problems, an object of the present invention is to equip the industrial vehicle with a steering chain having a drive chain and a sprocket driven by a steering cylinder, so that the front and rear wheels are the same without limiting the steering angle. Steering in the direction so that the vehicle travel direction can be easily switched.

Another object of the present invention is to make a differential driving function of the left and right wheels effectively by mounting a differential driving device which is configured in a simple configuration in the industrial vehicle to drive the left and right wheels differentially.

In order to achieve the above object, the present invention provides a steering and driving system of an industrial vehicle including a steering device having a drive chain and a sprocket driven by a steering cylinder and a differential driving device having a simple configuration.

The steering and driving system of an industrial vehicle according to the present invention is provided in a hydraulic oil chamber and a hydraulic oil chamber in which left and right input ports are formed in an industrial vehicle in which front and rear wheels, which are formed of left and right wheels, are respectively installed at the front and rear of the vehicle body. The steering cylinder is moved left and right by the pressure oil supplied to the left and right input ports, and the left and right sprockets driven by the drive chain connected to both ends of the steering cylinder, and left and right pivots coupled to the left and right sprockets. The front and rear wheel steering cases installed, the rotary valve connected to the steering pump and the hydraulic tank to discharge the hydraulic oil from the steering pump to the left and right cylinder ports as the steering wheel rotates, the front wheel steering case and the rear wheel steering case The front and rear wheels include a first flow path for connecting and second and third flow paths for connecting the rotary valve and the front and rear steering cases. It is equipped with a driving hydraulic motor for driving the left and right wheels differentially according to the resistance applied to the wheel connected to the steering device and the driving pump to steer, and is coupled to the left and right pivots and includes left and right wheels that rotate integrally. It comprises a differential drive device.

The above-mentioned differential driving device includes left and right wheels installed on left and right sides of the vehicle body, left and right driving hydraulic motors connected in parallel to a driving pump to drive left and right wheels, and left and right wheels and left and right insides. It consists of a gear case coupled to the pivot shaft, including a gear train that connects the right driven hydraulic motor, and the flow rate distributed from the driving pump to the left and right driven hydraulic motor changes according to the resistance applied to the left and right wheels. It is desirable to drive the right wheel differentially.

In addition, the second flow path connects the rotary valve right cylinder port and the right cylinder hydraulic input port of the front steering wheel, and the first flow path connects the left input port of the front wheel steering case hydraulic cylinder and the rear input steering port hydraulic cylinder. The third flow path may be configured to connect the right input port of the rear wheel steering case hydraulic cylinder and the left cylinder port of the rotary valve.

In addition, the first flow path connects the right channel connecting the right input port of the front steering wheel hydraulic cylinder and the left input port of the rear steering wheel to each other and the left input port of the front steering wheel hydraulic cylinder and the right input port of the rear steering wheel. The second flow path may be configured to connect the rotary valve right cylinder port and the right flow path, and the third flow path may be configured to connect the rotary valve left cylinder port and the left flow path, wherein the steering apparatus is provided from the rotary valve. It is preferable to further include at least one solenoid valve for opening and closing the pressure oil flow to the front and rear wheel steering case.

Hereinafter, with reference to the preferred embodiments of the accompanying drawings, looks at the configuration and operation of the steering and driving system of the industrial vehicle according to the present invention in more detail.

2 is a perspective view of an industrial vehicle having a steering and driving system according to an embodiment of the present invention.

Industrial vehicle 1 according to the present invention is equipped with front and rear wheels (20f, 20r) to the front and rear of the lower frame 2, the cab (3a) is provided with a steering wheel 131 above the upper frame (3). A boom assembly 30 is installed, which is mounted and includes a work tool 31. When the boom assembly 30 is rotated with respect to the upper frame 3, the work machine 31 also performs the operation while moving up and down with respect to the upper frame (3). The upper frame 3 is rotatably installed with respect to the lower frame 3, and the second main arm 33 of the boom assembly 30 is installed to be movable relative to the first main arm 32. The position of 31 can be extended to the front of the vehicle 1.

3 is a schematic diagram of a steering apparatus according to an embodiment of the present invention.

The front wheel 20f and the rear wheel 20r are composed of left and right wheels 21a, 21b, 22a, and 22b, respectively, and are installed at the front and rear lower sides of the lower frame 2, respectively, by the steering apparatus 100. ) And the rear wheel 20r are made to rotate in the same direction without restricting the steering angle.

The steering apparatus 100 largely includes front and rear wheel steering cases 110 and 120, a rotary valve 130, a first flow passage 140, a second flow passage 150, and a third flow passage 160.

Front and rear wheel steering cases 110 and 120 are installed in front and rear of the lower frame 2 to steer the front and rear wheels 20f and 20r, respectively. The rotary valve 130 supplies pressure oil to the front and rear wheel steering cases 110 and 120, and the first, second and third flow paths 140, 150 and 160 are the rotary valve 130, the front wheel steering case 110 and the rear wheel steering case. It serves to connect each of the 120.

The front and rear wheel steering cases 110 and 120 have the same configuration, are symmetrical in the front-rear direction, and are installed below the lower frame 2, and the left and right wheels 21a, 21b, 22a, and 22b are respectively provided in the steering cases 110 and 120. In connection, the hydraulic oil is supplied to the steering cases 110 and 120 to steer the left and right wheels 21a, 21b, 22a, and 22b.

Figure 4a is a schematic view of the steering case included in the steering apparatus of Figure 3, Figure 4b is an operating state of the steering case when the left turn of the steering apparatus of Figure 4a, Figure 4c is an operating state of the steering case when the right turn of the steering apparatus of Figure 4a to be.

The illustrated steering case represents the rear wheel steering case 120, and as shown in FIG. 3, the front wheel steering case 110 has the same configuration as the rear wheel steering case 120 and is symmetrical in the front-rear direction with respect to the lower frame 2. Since only the configuration of the rear wheel steering case 120 will be described here.

The steering case 120 includes a hydraulic oil chamber 121 installed in the housing 125, a steering cylinder 122, a drive chain 123, left and right sprockets 124a and 124b, and a left and right pivot ( 125a, 125b). Left and right wheels 22a and 22b are connected to the left and right pivot shafts 125a and 125b, respectively, so that steering of the left and right wheels 22a and 22b is achieved when the steering cylinder 122 is moved left and right.

Left and right input ports 121a and 121b are formed in the hydraulic oil chamber 121 of the steering case 120, and the steering cylinder 122 is installed in the hydraulic oil chamber 121 so as to be movable left and right. In the middle of the steering cylinder 122, a piston 122a for dividing the inside of the oil pressure chamber 121 into left and right regions is formed, and the action of the hydraulic oil input through the oil pressure chamber 121 left and right input ports 121a and 121b. By the piston 122a is moved left and right by the steering cylinder 122 is moved left and right.

The driving chain 123 is connected to both ends of the steering cylinder 122, and left / right sprockets 124a and 124b are installed to be spaced apart from both ends of the steering cylinder 122, and the driving chain 123 and the left / right sprocket ( Since the 124a and 124b are engaged, the left and right sprockets 124a and 124b are driven by the drive chain 123 to rotate. Since the steering cylinder 122 and the drive chain 123 are connected through the set screw 122b, the tension acting on the drive chain 123 can be adjusted by rotating the set screw 122b.

Left and right pivot axes 125a and 125b are coupled to the center of each of the left and right prockets 124a and 124b. The upper ends of the left and right pivots 125a and 125b are fixed to the centers of the left and right sprockets 124a and 124b and the lower ends are combined with a gear case 320 to be described later. As the first pivots 125a and 125b are rotated, the gear case 320 also rotates integrally.

According to such a configuration, unlike the conventional steering device in which the steering angle is limited, the wheels are steered to the left and right by 90 °, respectively, and have a feature capable of steering in the range of 180 °.

Pressure oil must be supplied to the left and right input ports 121a and 121b of the pressure oil chamber 121, and the rotary valve 130 installed at a predetermined position of the vehicle serves to supply the pressure oil. The rotary valve 130 is connected to the steering wheel 131, the steering pump 132 and the hydraulic tank 133, and rotates the hydraulic oil from the steering pump 132 as the steering wheel 131 rotates. Discharge to (130a, 130b).

The rotary valve 130 and the front and rear wheel steering cases 110 and 120 are connected by the first flow path 140 and the second and third flow paths 150 and 160. The first flow path 140 connects the front wheel steering case 110 and the rear wheel steering case 120, and the second and third flow paths 150 and 160 connect the rotary valve 130 and the front and rear wheel steering cases 110 and 120. ).

The first flow passage 140 includes a right flow passage 140b and a left flow passage 140a. The right channel 140b connects the right input port 111b of the front wheel steering case 110 and the left input port 121a of the rear wheel steering case 120, and the left channel 140a is the front wheel steering case 110. The left input port 111a of) and the right input port 121b of the rear wheel steering case 120 are connected.

The second flow path 150 connects the rotary cylinder 130 to the right cylinder port 130b and the right flow path 140b, and the third flow path 160 connects the rotary valve 130 to the left cylinder port 130a. ) And the left flow passage 140a, the rotary valve 130 and the front and rear wheel steering case (110, 120) is in communication with each other.

Solenoid valves 141a and 141b are installed in the left flow passage 140a and the right flow passage 140b of the first flow passage 140 to block / communicate the flow of the pressurized oil. When the solenoid valves 141a and 141b communicate the flow of the hydraulic oil, the pressure oil from the rotary valve 130 is supplied to both the front wheel steering case 110 and the rear wheel steering case 120, but the solenoid valves 141a and 141b are When the hydraulic oil is cut off, the hydraulic oil from the rotary valve 130 is supplied only to the front wheel steering case 110, so that only the front wheel 20f is steered and the rear wheel 20r is not steered, so that steering is performed like a general front wheel steering device.

Hereinafter, the operation of the steering apparatus 100 having such a configuration will be described. When the steering wheel 131 is rotated to the left to rotate the vehicle to the left, the hydraulic oil from the rotary valve 130 passes through the left cylinder port 130a, the third flow path 160 and the left flow path 140a to the front wheels. It is supplied to each of the left input port 111a of the steering case 110 and the right input port 121b of the rear wheel steering case 120. Accordingly, the steering cylinder 112 of the front wheel steering case 110 moves to the right side, and the steering cylinder 122 of the rear wheel steering case 120 moves to the left side so that both the front wheel 20f and the rear wheel 20r are in the same direction to the left. Steering Therefore, the driving direction of the vehicle can be easily changed without driving and rotating the vehicle, so that the work can be smoothly performed even in a narrow space. In addition, when driving a vehicle on a general road, the solenoid valves 141a and 141b may be operated to block the pressure oil supply to the rear wheel steering case 120 so that only the front wheel 20f may be steered.

5 is a front view of the driving device viewed from the line A-A of FIG.

The differential drive device 300 includes left and right wheels 22a and 22b, left and right driving hydraulic motors 310a and 310b and a gear case 320 installed on the left and right sides of the lower frame 2. Is done.

The upper portion of the gear case 320 is connected to the pivot shafts 125a and 125b, and the upper ends of the pivot shafts 125a and 125b are fixed to the center of the sprockets 124a and 124b. Therefore, as the sprockets 124a and 124b are driven and rotated by the drive chain 123, the pivot shafts 125a and 125b and the gear case 320 rotate together. In addition, the gear case 320 is provided with a reduction gear train 324 comprising a drive gear 321 coupled to the drive hydraulic motors 310a and 310b shafts and a driven gear 322 engaged with the drive gear 322. do.

The left and right driving hydraulic motors 310a and 310b mounted on the gear case 320 serve to differentially drive the left and right wheels 22a and 22b. The left and right driving hydraulic motors 310a and 310b are fixed to the gear case 320 such that the rotation shaft 325 is located inside the gear case 320, and the driving gear 321 is coupled to the rotation shaft 325. The axle 323, one end of which is connected to the center of the wheels 22a and 22b, is installed such that the other end is inserted into the gear case 320. At the other end of the axle 323, the driven gear 322 is installed to engage with the drive gear 321. Therefore, when the hydraulic oil is supplied from the driving pump 340 and the driving hydraulic motors 310a and 310b rotate, the driving force is transmitted to the axle 323 through the reduction gear train 324 to drive the wheels 22a and 22b.

As described above, since the left and right driving hydraulic motors 310a and 310b are connected in parallel with the driving pump 340, the driving pump 340 when the resistances added to the left and right wheels 22a and 22b are the same. The flow rates supplied to the left and right driving hydraulic motors 310a and 310b are the same, and the left and right wheels 22a and 22b are driven by the same driving force. When a difference occurs in the resistance applied to the left and right wheels 22a and 22b, the load acting on the left and right driving hydraulic motors 310a and 310b is different, and therefore the left and right driving hydraulic pressure is driven from the driving pump 340. The flow rates supplied to the motors 310a and 310b are also different, so that the left and right wheels are driven differentially by different driving forces.

6 is a schematic diagram of a steering apparatus 200 according to another embodiment of the present invention.

The first flow path 240 connects the front wheel steering case 110 and the rear wheel steering case 120, and the second and third flow paths 250 and 260 connect the rotary valve 130 and the front and rear wheel steering cases 110 and 120. ), The pressure oil supplied from the rotary valve 130 to the front and rear wheel steering case (110, 120) by the first, second and third flow paths (240, 250, 260) is the same as the above-described embodiment, Other identical components are described using the same symbols.

However, the second flow path 250 connects the rotary valve 130 right cylinder port 130b and the right input port 111b of the front wheel steering case 110, and the first flow path 240 is a front wheel steering case ( 110, the left input port 111a and the rear wheel steering case 120, the left input port 121a are connected, and the third flow path 260 is the rear wheel steering case 120 right input port 121b and the rotary valve 130. To the left cylinder port (130a). As such, the front wheel steering case 110, the rear wheel steering case 120, and the rotary valve 130 are connected in series, so the oil pressure from the rotary valve 130 is input to the front wheel steering case 110 and the front wheel steering case 110. The hydraulic oil from) is input to the rear wheel steering case 120 again, and steering cylinders 112 and 122 of the front and rear wheel steering cases 110 and 120 are operated to steer the front and rear wheels 20f and 20r.

When the steering wheel 131 is rotated to the left to rotate the vehicle to the left, the hydraulic oil from the rotary valve 130 passes through the left cylinder port 130a and the third flow path 260 of the rear wheel steering case 120. By supplying to the right input port 121b, the steering cylinder 122 is moved to the right, and the rear wheel 20r is steered to the left. The hydraulic oil from the left wheel input port 121a of the rear wheel steering case 120 is input to the front wheel steering case 110 through the left input port 111a of the first flow path 240 and the front wheel steering case 110. The steering cylinder 112 of 110 moves to the right and the front wheel 20f is steered to the left.

The steering cylinders 112 and 122 of the front and rear wheel steering cases 110 and 120 are moved in opposite directions so that the front and rear wheels 20f and 20r are steered in the same direction so that the driving direction of the vehicle can be easily changed without driving and rotating the vehicle. It can be done smoothly even in a small space.

In this embodiment, since the front and rear wheel steering cases 110 and 120 and the rotary valve 130 are connected in series, the above-described solenoid valve cannot be installed, so that the front and rear wheels 20f and 20r are always interlocked and steered. Have

FIG. 7 is an operating state diagram in which an industrial vehicle loads an object into a work machine according to an embodiment of the present invention, and FIG. 8 is an operation state diagram in which the industrial vehicle of FIG. 7 rotates to lay down an object.

If the place where the object is placed is close to the place where the object is to be loaded due to the characteristics of the work performed in a narrow place, it is not necessary to rotate the entire vehicle by loading the object on the work machine 31 and performing the operation such as reversing, rotating, or moving the vehicle again. By operating only the upper frame turning device mounted separately, only the direction of the work machine 31 can be rotated to easily perform the work.

In order for the industrial vehicle 1 according to the present invention to move the object 10 from the place C to a new loading place E, after the object 10 is loaded on the work machine 12 of the vehicle 11 at the place C, After the rear wheels 20f and 20r are steered in the place E direction, the upper frame 3 is rotated in the place E direction, so that the traveling direction of the vehicle 1 and the direction of the work machine 31 are easily switched to the place E direction. . Not only can the object be put down in this state, but also the length of the boom assembly 30 can be lowered to place the object 10 in a proper position in front of the vehicle 1. Therefore, the operation can be performed without unnecessary operation such as moving the vehicle forward and backward, and the object can be moved quickly even in a narrow space.

According to the steering and driving system of the industrial vehicle of the present invention as described above, the front and rear wheels are steered in the same direction without limiting the steering angle by mounting a steering device having a drive chain and a sprocket driven by a steering cylinder in the industrial vehicle. The driving direction is easily changed even in a narrow work space, and the differential driving of the left and right wheels is effectively performed.

Claims (5)

delete delete In an industrial vehicle in which front and rear wheels, which consist of left and right wheels, are respectively installed at the front, rear, and lower sides of a vehicle body, Left and right sprockets installed in the oil pressure chamber having left and right input ports and the steering cylinders which are installed in the oil pressure chamber and are moved to the left and right by pressure oil supplied to the left and right input ports, and are driven by driving chains connected to both ends of the steering cylinders. It is connected to the front and rear wheel steering cases respectively installed at the front and rear of the vehicle body, including the left and right pivots coupled to the left and right sprockets, and is connected to a steering pump and a hydraulic tank, and the hydraulic pressure from the steering pump is changed according to the rotation of the steering wheel. A rotary valve discharged to the right cylinder port, a first flow path connecting the front wheel steering case and the rear wheel steering case, and a second flow path and a third flow path connecting the rotary valve and the front and rear wheel steering cases. Steering devices for steering the rear wheels; And A differential driving device including a left and right wheel which is connected to the driving pump and is equipped with a driving hydraulic motor for differentially driving the left and right wheels according to the resistance applied to the wheels and is integrally rotated by being coupled to the left and right pivots. ; Consists of including The second flow path connects the rotary valve right cylinder port and the right cylinder hydraulic input port of the front wheel steering case, and the first flow path is the left input port of the front wheel steering case hydraulic cylinder and the left side of the rear wheel steering case hydraulic cylinder. And an input port, wherein the third flow path connects a right input port of the rear wheel steering case hydraulic cylinder and a left cylinder port of the rotary valve. In an industrial vehicle in which front and rear wheels, which consist of left and right wheels, are respectively installed at the front, rear, and lower sides of a vehicle body, Left and right sprockets installed in the oil pressure chamber having left and right input ports and the steering cylinders which are installed in the oil pressure chamber and are moved to the left and right by pressure oil supplied to the left and right input ports, and are driven by driving chains connected to both ends of the steering cylinders. It is connected to the front and rear wheel steering cases respectively installed at the front and rear of the vehicle body, including the left and right pivots coupled to the left and right sprockets, and is connected to a steering pump and a hydraulic tank, and the hydraulic pressure from the steering pump is changed according to the rotation of the steering wheel. A rotary valve discharged to the right cylinder port, a first flow path connecting the front wheel steering case and the rear wheel steering case, and a second flow path and a third flow path connecting the rotary valve and the front and rear wheel steering cases. Steering devices for steering the rear wheels; And A differential driving device including a left and right wheel which is connected to the driving pump and is equipped with a driving hydraulic motor for differentially driving the left and right wheels according to the resistance applied to the wheels and is integrally rotated by being coupled to the left and right pivots. ; Consists of including The first flow path connects a right flow path connecting the right input port of the front wheel steering case hydraulic cylinder and the left input port of the rear wheel steering case to the left input port of the front wheel steering case hydraulic cylinder and the right input port of the rear wheel steering case. The left channel is connected to each other, the second flow path connects the rotary valve right cylinder port and the right flow path, and the third flow path connects the rotary valve left cylinder port and the left flow path. Vehicle steering and drive system. The method of claim 4, wherein The steering apparatus further comprises at least one solenoid valve for opening and closing the hydraulic oil flow from the rotary valve to the front and rear wheel steering case.

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