JPH0667741B2 - Steering device for tracked vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a tracked vehicle having left and right crawler belts with respect to a traveling direction, and an operation for giving a rotational speed difference to left and right crawler belts to perform a turning operation. Device.

(b) Conventional technology Among vehicles that run on soft land on the road surface, there are tracked vehicles equipped with crawler tracks on the left and right with respect to the traveling direction. This tracked vehicle has sufficient thrust to travel on rough roads due to the large contact area provided by the track. Such a tracked vehicle is generally provided with a steering device that stops transmission of driving force and supplies braking force to the crawler belt on the turning direction side during turning operation. When the transmission of the driving force or the supply of the braking force to one crawler belt is performed by this steering device, a difference in rotational speed occurs between the left and right crawler belts, and the vehicle body turns to the crawler belt side having a low rotational speed.

When the transmission of the driving force is stopped with respect to the crawler belt on the turning direction side, the rotation of the crawler belt is not restricted, so that the crawler belt on the turning direction side also rotates as the vehicle body moves forward during the turning operation,
The radius of gyration becomes relatively large. On the other hand, when a braking force is supplied to the crawler belt on the turning direction side, the rotation of the crawler belt is restricted. Therefore, the forward movement of the vehicle body during the turning operation does not cause the crawler belt on the turning direction side to rotate, and The position of the side crawler belt hardly changes, and the turning radius becomes smaller. Therefore, when relatively small turning force is sufficient, such as when correcting the traveling direction, transmission of driving force is stopped, and when a large turning force is required when reversing the traveling direction, braking force is required. To supply.

(c) Problems to be Solved by the Invention However, in the conventional steering device for a tracked vehicle, when a turning operation is performed on a soft land, the turning position of the vehicle body hardly changes, and In some cases, the crawler belt sinks into the road surface, and the crawler belt on the side opposite to the turning direction slips on the road surface, making it impossible to smoothly perform the turning motion. In particular, when the braking force is supplied to the crawler belt on the turning direction side to rotate, the crawler belt position on the turning direction side does not change at all, so that the crawler belt is likely to sink and slip, so that the turning motion can be performed smoothly. could not.

An object of the present invention is to transmit a driving force to a crawler belt on the turning direction side at a time interval according to a vehicle speed while executing a turning operation for supplying a braking force to the crawler belt on the turning direction side to turn the vehicle body. By changing the position, it is possible to prevent the crawler belt from sinking or slipping due to the turning motion being performed at the same turning position, and to minimize the straight part during the turning motion to perform a smooth and quick turning motion. (EN) Provided is a steering device for a tracked vehicle capable of performing the following.

(d) Means for Solving the Problems A steering device for a tracked vehicle according to the present invention is a steering device for a tracked vehicle that stops transmission of driving force and supplies braking force to a crawler belt on the turning direction side. In which intermittent driving means for intermittently transmitting the driving force to the crawler belt being supplied with braking force, speed detecting means for detecting the traveling speed of the vehicle body, and intermittent driving means according to the detected speed of the speed detecting means And a braking time changing means for increasing / decreasing the braking force supply time with respect to the driving force transmission time per unit time.

(e) Action In the steering device for a tracked vehicle of the present invention, the driving force is intermittently supplied by the intermittent driving means to the crawler belt on the turning direction side to which the braking force is supplied during the turning operation. The traveling speed of the vehicle body during the turning operation is detected by the speed detecting means, and based on the detection result of the speed detecting means, the braking time changing means increases or decreases the braking force supply time with respect to the driving force transmission time of the intermittent driving means. . Therefore, the braking time changing means increases the braking force supply time with respect to the driving force transmission time when the traveling speed of the vehicle body during the turning operation increases, and decreases it when the traveling speed decreases. Therefore, the driving force transmission time by the intermittent driving means decreases as the traveling speed during the turning operation increases, and the driving force transmission time by the intermittent driving means increases as the traveling speed decreases. As a result, the changing distance of the turning position by the intermittent driving means, that is, the straight traveling distance during the turning operation becomes substantially constant regardless of the traveling speed during the turning operation.

(f) Embodiment FIG. 1 is a schematic diagram including a hydraulic circuit diagram showing a steering device for a tracked vehicle according to an embodiment of the present invention.

The steering device 1 is provided between a transmission gear 2 to which the rotation of the engine (not shown) is supplied and drive wheels 10a and 10b that rotate the crawler belt. An internal gear 4 is formed on the input gear 3 that meshes with the transmission gear 2. The output gears 5a, 5b slidable in the axial direction with respect to the rotating shaft 6 of the input gear 3 can be meshed with the internal gear 4. Further, output shaft gears 8a and 8b are constantly meshed with the output gears 5a and 5b.
The output shaft gears 8a, 8b are fixed to the other ends of the output shafts 9a, 9b having the drive wheels 10a, 10b fixed to one end. With the above-described configuration, the steering device 1 transmits the rotation of the transmission gear 2 to the drive wheels 10a, 10b via the input gear 3, the internal gear 4, the output gears 5a, 5b and the output shaft gears 8a, 8b. Brake shoes 5c and 5d are attached to the output gears 5a and 5b. When the output gears 5a and 5b slide on the rotary shaft 6, the output gears 5a and 5b do not mesh with the internal gear 4, and the brake shoes 5c and 5d are connected to the brakes 7a and 7b. Abut.

One ends of links 11a and 11b are engaged with the output gears 5a and 5b. Piston rods 14a and 14b of cylinders 12a and 12b are locked to the other ends of the links 11a and 11b. The cylinders 12a and 12b are connected to a pump 18 via a direction switching valve 16. The direction switching valve 16 is an electromagnetic switching valve including solenoids SOL1 and SOL2, and drives the solenoid SOL1 or SOL2 to guide the pressure oil supplied from the pump 18 to either the left cylinder 12a or the right cylinder 12b. Cylinder 12a, 1
The return ports 15a, 15b of 2b communicate with the tank via the check valves 19a, 19b and the switching valve 17. This switching valve 17 is a solenoid
It is an electromagnetic switching valve equipped with SOL3. Further, a switching valve 21 which is an electromagnetic switching valve having a solenoid SOL4 is provided between the direction switching valve 16 and the tank 18. The switching valve 21 returns the pressure oil in the hydraulic circuit to the tank by driving the solenoid SOL4.

With the above configuration, the solenoid SOL1 in the directional control valve 16
When driven, the directional control valve 16 is in the position P1 and the pressure oil supplied from the pump 18 is transferred to the left cylinder 12
lead to a. As a result, the piston 13a moves in the direction of arrow A to the position of the return port 15a. The movement of the piston 13a in the arrow A direction is transmitted to the output gear 5a via the piston rod 14a and the link 11a, and the output gear 5a slides in the arrow C direction with respect to the rotary shaft 6. When the piston 13a reaches the position of the return port 15a, the output gear 5a does not mesh with the internal gear 4. As a result, the rotation of the transmission gear 2 is transmitted only to the right output gear 5b via the input gear 3 and the internal gear 4 and is not transmitted to the left output gear 5a. For this reason, the transmission of the driving force to the left output shaft gear 8a, the output shaft 9a, and the drive wheel 10a is stopped, and the rotational speeds of the left and right crawler belts differ. When the piston 13a reaches the position of the return port 15a,
After this, all the pressure oil supplied to the cylinder 12a is returned to the tank from the return port 15a via the check valve 19a and the switching valve 17. Therefore, when only the solenoid SOL1 is driven, the piston 13a stops at the position of the return port 15a, and the transmission of the driving force to the left drive wheel 10a is continuously stopped.

When the directional control valve 16 is in the position P1 and the solenoid SOL3 is driven, the connection between the return port 15a and the tank is closed. Therefore, the pressure oil supplied to the cylinder 12a does not flow out to the outside, and the piston 13a further moves in the direction of arrow A from the position of the return port 15a. This piston 13
The movement of a is transmitted to the output gear 5a via the piston rod 14a and the link 11a. When the piston 13a is located in the direction of arrow A from the return port 15a, the brake shoe 5c brakes.
Contact 7a. This contact restricts the rotation of the output gear 5a, and the braking force is supplied to the output shaft gear 8a, the output shaft 9a, and the drive wheel 10a. Even in this case, the transmission gear 2 rotates through the input gear and the internal gear 4 and the right output gear 5b.
, The difference in rotational speed between the left and right crawler belts is further increased.

When the solenoid SOL1 of the direction switching valve 16 and the solenoid SOL3 of the switching valve 17 are driven, when the solenoid SOL4 of the switching valve 21 is driven, the pressure oil in the hydraulic circuit is returned to the tank. As a result, the pressure oil that has moved the piston 13a in the direction of arrow A in the left cylinder 12a also switches the switching valve 21.
Then, the piston 13a is returned to the position shown in FIG. 1, and the left output gear 5a meshes with the internal gear 4 again. Therefore, the same driving force as that of the right driving roller 10b is transmitted to the left driving roller 10a, the rotational speeds of the left and right crawler belts match, and the vehicle body goes straight.

The above operation is the same when the right solenoid SOL2 in the directional control valve 16 is driven, and the transmission of the driving force and the supply of the braking force are performed to the right driving wheel 10b.

FIG. 2 is a block diagram showing a main part of a control unit of a tracked vehicle equipped with the above steering device.

The operation amount of the steering lever 41 provided on the cockpit (not shown) is detected by the volume VR and input from the A / D converter 35 to the CPU 31 via the I / O interface 34. Also,
The on / off states of the switches SW1 and SW2, which are the selection means of the present invention, are input to the CPU 31. The CPU 31 uses the solenoid 32, 3
Output control data to 7. A part of the memory area of the RAM 33 is assigned to the working area at this time.
The solenoid drivers 36 and 37 drive the solenoids SOL1 to SOL4 according to the output control data. The solenoid driver 37 has a pulse oscillator inside and applies a pulse voltage of a constant cycle to the solenoid SOL4.

The ROM 32, which constitutes a part of the control unit, stores the relationship between the output value of the volume VR shown in FIG. 4 and the drive duty ratio of the solenoids SOL1 to SOL3. The volume VR outputs the output value S when the steering lever 41 is in the neutral state. When the steering lever 41 is operated to the left from this neutral state, the output value of the volume VR gradually decreases. On the contrary, when the steering lever 41 is operated to the right from the neutral state, the output value of the volume VR gradually increases. When the steering lever 41 is operated to the left, the output of the volume VR gradually decreases. While the output value of the volume VR decreases from Sk to Sa, the drive time of the solenoid SOL1 per unit time is gradually increased. Here, a dead zone of ± k is provided in the neutral state of the steering lever 41, and when the output value of the volume VR is in the range of S ± k, it is assumed that the steering lever 41 is in the neutral state and neither solenoid is driven. Further, the predetermined value S-a is a value set in advance as an intermediate value, and when the output value of the volume VR reaches the predetermined value S-a, the solenoid
The SOL1 duty ratio becomes 100%. When the output value of the volume VR falls below the predetermined value Sa, the drive duty ratio of the solenoid SOL1 remains 100% and the solenoid SOL
The drive duty ratio of 3 gradually increases.

When the steering lever 41 is operated to the right from the neutral state, the drive duty ratio of the solenoid SOL2 is gradually increased while the output value of the volume VR changes from the neutral state range S + k to the predetermined value S + a. When the output value of the volume VR exceeds the predetermined value S + a, the drive duty ratio of the solenoid SOL2 remains at 100% and the drive duty ratio of the solenoid SOL3 is gradually increased.

3 (A) and 3 (B) are flowcharts showing a part of the processing procedure of the control unit of the tracked vehicle.

When a change in the output value of the volume VR is input to the CPU 31 by operating the steering lever 41, it is determined whether or not the output value of the volume VR is within the neutral range S ± k (n1). When the output value of the volume VR is not within the range S ± k of the neutral state, it is determined whether the output value is less than or equal to the range of the neutral state (n2). Here, it is determined whether the steering lever 41 has been operated to the left or right. When the steering lever 41 is operated to the left, the output value of the volume VR is the predetermined value S
It is checked whether it is less than or equal to -a (n3). The output value of the volume VR is in the neutral range Sk and the predetermined value Sa
If it is in between, the duty ratio of the solenoid SOL1 is read from the ROM 32, and the solenoid SOL1 is on / off controlled according to this duty ratio (n4, n5).

When the output value of the volume VR is less than or equal to the predetermined value Sa, it is checked whether or not the switch SW1 is turned on (n6), and when the switch SW1 is off, the solenoid SOL1 is constantly driven. At the same time, the solenoid SOL3 is driven at the duty ratio shown in FIG. 4 (n7 to n9). When the steering lever 41 is operated by a predetermined amount or more as described above,
Transmission of the braking force to the left crawler is stopped by driving the solenoid SOL1. In addition to this, the solenoid SOL3 is driven at a duty ratio according to the operation amount of the steering lever 41, and the braking force is supplied to the crawler belt on the left side at a predetermined duty ratio.

If switch SW1 is on, solenoid SOL
1 and SOL3 are always driven (n10, n11), and the duty ratio of solenoid SOL4 according to the vehicle speed is read from ROM32 (n
12). The ROM 32 stores the relationship between the vehicle speed shown in FIG. 5 and the drive duty ratio of the solenoid SOL4. CPU31
Reads the duty ratio of the solenoid SOL4 according to the detection result of the vehicle speed sensor S1 input from the A / D converter 38, and drives and controls the solenoid SOL4 according to this duty ratio (n12, n13). As described above, the steering lever 41
Is moved to the bent portion 42a on the left side of the guide 42 shown in FIG. 8 and the switch SW1 is turned on, the solenoids SOL1 and S
OL3 is always driven, and solenoid SOL4 is driven according to the duty ratio shown in FIG. As a result, the steering device repeatedly supplies the braking force and the driving force to the left crawler belt. At this time solenoid SOL4
The on-time per unit time t of decreases with vehicle speed as shown in FIG. As a result, as the vehicle speed increases, the braking force supply time with respect to the driving force transmission time per unit time t increases.

At n2, the output value of the volume VR is in the neutral state range S +
If it is larger than k and the steering lever 41 is operated to the right, the processing of n14 to n24 is performed. That is, volume VR
Is between the neutral range S + k and the predetermined value S + a, the solenoid SOL2 is drive-controlled based on the duty ratio shown in FIG. 4 at n14 to n16. As a result, transmission of the driving force to the right crawler belt is stopped at a predetermined duty ratio. The output value of the volume VR is a predetermined value S
When it is + a or more, the solenoid SOL2 is constantly driven by n17 to n20, and the solenoid SOL3 is drive-controlled based on the duty ratio shown in FIG. As a result, the steering device 1 supplies the braking force to the right crawler belt in which the transmission of the driving force is stopped at a predetermined duty ratio.

The steering lever 41 has a bent portion 42 on the right side of the guide 42 shown in FIG.
When the switch SW2 is turned on and the switch SW2 is turned on, the solenoids SOL2 and SOL3 are always driven by the processing of n21 to n24, and the solenoid SOL4 is drive-controlled at the duty ratio shown in FIG. As a result, the steering device 1 intermittently transmits the driving force to the right crawler belt in the braking force supply state at a predetermined duty ratio.

In the above, n10 to n13 and n21 to n24 are the switches SW1 and SW.
2 and a switching valve 21 including a solenoid SOL4 correspond to the intermittent drive means of the present invention, and particularly n12, n13 and n23, n24
Corresponds to the braking time changing means of the present invention.

As described above, according to this embodiment, as shown in FIG. 6, the driving force is transmitted per unit time t to the crawler belt on the turning direction side according to the operation amount from the neutral state of the steering lever 41. The ratio of the drive transmission stop time (clutch off) to the state (clutch on) increases. In addition, the steering lever 41
When is operated, the ratio of the braking force supply state (brake on) to the driving force transmission stopped state (clutch off) per unit time t increases with respect to the crawler belt on the turning direction side.

When the switch SW1 or SW2 is turned on by the operation of the steering lever 41, the driving force is intermittently transmitted (clutch on) with a predetermined duty ratio to the crawler belt on the turning direction side to which the braking force is supplied. The duty ratio related to this driving force transmission is obtained by the relationship shown in FIG. Therefore, the ratio of the driving force transmission state (clutch on) and the braking force supply state (brake on) per unit time t to the crawler belt on the turning direction side changes as shown in FIG. 7 in accordance with the change in vehicle speed. As shown in the figure, when the vehicle speed increases, the braking force supply time increases and the driving force transmission time decreases.

FIG. 9 is a hydraulic circuit diagram showing another embodiment of the present invention.

The cylinders 12a and 12b of the steering device 1 are connected to a pump 92 via a direction switching valve 91. Direction switching valve 91 is 6 port 5
It is a position directional control valve, and by operating the steering lever 41, it changes from the neutral state shown in the figure to the states of positions P5 to P8. Direction switch valve when steering lever 41 is operated to the left
91 is in the state of position P7 and supplies pressure oil to the left cylinder 12a. In this position P7, the piston
After 13a reaches the return port 15a, the pressure oil supplied into the cylinder 12a is returned to the tank from the return port 15a, and the steering device 1 continuously stops the supply of the braking force to the left crawler belt.

When the steering lever 41 is operated further to the left, the direction switching valve
91 is in the position P8. At this time, the steering lever
The return amount of the pressure oil from the return port 15a to the tank is reduced according to the operation amount of 41, and the outflow amount of the pressure oil in the cylinder 12a gradually becomes smaller than the inflow amount. Thereby, the braking force is supplied to the steering device 1 to the left crawler belt. Steering lever
When 41 is operated to the right, the positions P5 and P6 are set, and the steering device 1 stops the transmission of the driving force and the supply of the braking force to the crawler belt on the right side. The position
The variable throttles in P6 and P8 are provided with wedge-shaped notches whose intervals change in the moving direction of the partition of the spool of the direction switching valve 91. As a result, the steering lever 41
When the spool is moved by the above operation, the interval between the notches facing the port changes, and the flow rate of the pressure oil returning to the tank via the notch changes.

An accumulator 98 is connected between the direction switching valve 91 and the pump 92 via a switching valve 93, an unload valve 94, check valves 95, 96 and a variable throttle 97. The switching valve 93 is the steering lever 41.
The position P9 is set by the operation of. When the switching valve 93 is in the position P9, part of the pressure oil in the tank 92 is guided to the accumulator 98 via the check valve 96 and the variable throttle 97. Therefore, the pressure in the accumulator 98 increases, and the unload valve 94 operates due to this increase in pressure, and the pressure oil in the hydraulic circuit is communicated with the tank. As a result, the pressure oil in the cylinder 12a or 12b is also guided to the tank. At this time, the pressure oil in the accumulator 98 is also checked by the check valve.
It is led to the tank via 95. When the internal pressure of the accumulator 98 drops due to the pressure oil in the accumulator 98 being guided to the tank, the unload valve 94 returns to its original state, closing the space between the hydraulic circuit and the tank. This guides the pressure oil to the cylinder 12a or 12b.

When the switching valve 93 is in the position P9, the cylinder 12a or 12b is filled with the pressure oil and then the pump 92
The pressure oil supplied from is guided to the accumulator 98, so that the unload valve 94 operates due to the increase of the pressure oil pressure inside the accumulator 98. In this way, when the switching valve 93 is in the position P9, the pressure oil in the cylinder 12a or 12b is regularly guided to the tank. As a result, the steering device 1 alternately repeats the braking force supply state and the driving force transmission state. At this time, by setting the throttle amount of the variable throttle 97, the time required to increase the pressure of the accumulator 98 can be increased / decreased and the braking force supply time in the steering device 1 can be increased / decreased. Therefore, by connecting an adjusting member (not shown) of the variable throttle 97 to the accelerator lever, the throttle amount of the variable throttle 97 can be changed according to the vehicle speed, and the braking force supply time relative to the driving force transmission time can be changed according to the vehicle speed. Can be changed.
In the steering apparatus configured as described above, the switching valve 9
3, the unload valve 94 and the accumulator 98 correspond to the gap driving means of the present invention, and the variable throttle 97 also corresponds to the braking time changing means. With the above-described structure, the present invention can be embodied only by the hydraulic circuit and does not require the processing by the control unit.

(g) Effect of the Invention According to the present invention, when the crawler belt sinks or slips during the turning motion, the intermittent drive means is operated to operate the crawler belt on the turning direction side while the braking force is being supplied. The driving force can be transmitted intermittently. As a result, the turning position can be changed before the crawler belt sinks or slips, and the turning operation can be performed smoothly. Furthermore, the braking force supply time for the driving force transmission time changes according to the vehicle speed during the turning operation, and the braking force supply time for the driving force transmission time per unit time increases during the turning operation at high speed, When the turning operation is performed at a low speed, the braking force supply time is reduced with respect to the driving force transmission time per unit time. Therefore, regardless of the vehicle speed during the turning operation, the straight traveling distance of the vehicle body due to the transmission of the driving force to the crawler belt on the turning direction side becomes substantially constant, and the radius of gyration during the high-speed turning operation does not unnecessarily increase. The turning operation can always be performed smoothly and quickly.

[Brief description of drawings]

FIG. 1 is a schematic diagram including a hydraulic circuit diagram showing a steering device for a tracked vehicle according to an embodiment of the present invention, and FIG. 2 is a block diagram of a control section of a tracked vehicle equipped with the steering device. Figure 3 (A),
FIG. 4B is a flowchart showing a part of the processing procedure of the control unit, and FIG. 4 shows the relationship between the output value of the volume stored in the ROM forming a part of the control unit and the drive duty ratio of the solenoid. 5 and 5 are views showing the relationship between the vehicle speed and the drive duty ratio of other solenoids, which are also stored in the ROM, and FIG. 6 shows the transmission state of the driving force and the supply state of the braking force to the crawler belt of the steering device. FIG. 7 is a diagram showing a relationship with a steering lever operation amount; FIG. 7 is a diagram showing a relationship between a driving force transmission state and a braking force supply state of the steering device and a vehicle speed;
The drawing is a schematic plan view showing the vicinity of the steering lever of the same-track vehicle. FIG. 9 is a hydraulic circuit diagram showing another embodiment of the present invention. 1 ... Steering device, 21 ... Switching valve, S1 ... Vehicle speed sensor, SOL1-SOL4 ... Solenoid.

Claims (1)

[Claims] 1. In a steering device for a tracked vehicle that stops transmission of a driving force and supplies a braking force to a crawler belt on a turning direction side, the driving force is intermittently transmitted to a crawler belt to which a braking force is being supplied. Intermittent driving means, speed detecting means for detecting the traveling speed of the vehicle body, and braking for increasing / decreasing the braking force supply time with respect to the driving force transmission time per unit time in the intermittent driving means according to the level of the detected speed of the speed detecting means. A steering device for a tracked vehicle including time changing means.