JPH069987B2 - Steering device for tracked vehicle - Google Patents

Description

Description: (a) Field of Industrial Application The present invention relates to a tracked vehicle that travels on a soft land such as an agricultural vehicle and has crawler tracks on the left and right with respect to the traveling direction. In particular, the present invention relates to a steering device that gives a rotational speed difference to left and right crawler belts to perform a turning motion.

(b) Outline of the Invention In summary, the steering device for a tracked vehicle according to the present invention is summarized as follows: A drive shaft rotation detection for detecting the rotational speeds of a drive shaft and a driven shaft of a friction joint located between a drive device and a track. By providing the means and the driven shaft rotation detection means, the friction joint is intermittently operated so that the ratio of the detection values of both means and the operation amount of the steering lever matches a predetermined transmission ratio, and the turning radius of the vehicle body is increased. Is uniquely determined by the operation amount of the steering lever irrespective of the road surface condition, and the turning operation is simplified.

(c) Conventional technology Vehicles running on soft land on the road surface are equipped with crawler tracks on the left and right with respect to the traveling direction, and a large thrust is obtained by increasing the contact area. During such a turning operation of a tracked vehicle, the transmission of the driving force is stopped or the braking force is supplied to the crawler belt in the turning direction designated by the operation of the steering lever, and the difference in rotational speed is applied to the left and right crawler belts. Turn the car body. Therefore, the tracked vehicle is provided with a steering device including a friction joint and a braking device between the drive device and the left and right crawler belts. In this steering device, the transmission of the driving force by the friction joint is stopped to stop the transmission of the driving force, and the braking device is further operated to supply the braking force. When the transmission of the driving force to one of the crawler belts is stopped, a difference in rotational speed occurs between the left and right crawler belts, and the vehicle body turns to the crawler belt side where the transmission of the driving force is stopped. At this time, since the crawler belt on the turning direction side is not restricted in rotation, the crawler belt rotates as the vehicle body advances and the turning radius of the vehicle body becomes relatively large.
On the other hand, when the braking force is supplied to perform the turning motion,
The rotation of the crawler belt on the turning direction side is completely restricted, the crawler belt does not rotate as the vehicle body advances, and the turning radius of the vehicle body becomes smaller.
From the above, if the operation amount of the steering lever exceeds the predetermined amount, the transmission of the driving force to the crawler belt on the operating side is stopped, and the braking force is supplied after the operation amount exceeds the predetermined amount. The turning radius of the turning motion can be reduced according to the operation amount of the steering lever. Further, by increasing or decreasing the transmission stop time of the driving force and the supply time of the braking force per unit time according to the operation amount of the steering lever, it is possible to obtain a turning force substantially proportional to the operation amount of the steering lever. . The change of the turning force by the operation amount of the steering lever can also be performed by configuring the friction joint and the braking device with the multi-plate clutch and the multi-plate brake, and controlling the pressure applied to the clutch and the brake. .

(d) Problems to be Solved by the Invention However, none of the conventional steering devices for tracked vehicles described above consider the change in the transmission ratio of the driving force of the friction joint due to the road surface resistance. That is, when the transmission of the driving force is transmitted to the crawler belt at a predetermined transmission ratio in the friction joint, the rotation of the crawler belt is restricted when a large road surface resistance acts on the crawler belt. For this reason, the rotational speed of the crawler belt falls below the rotational speed determined by the rotational speed of the drive device and the transmission ratio of the friction joint, causing slippage in the friction joint and lowering the transmission ratio of the friction joint. In this way, even if the driving force transmission stop time by the friction joint is increased or decreased depending on the operation amount of the steering lever, there are cases where the turning force corresponding to the operation amount cannot be obtained due to the influence of road surface resistance. .

An object of the present invention is to detect the number of rotations of a driving shaft side and a driven shaft side of a friction joint so that a ratio between the two during a turning operation becomes a value corresponding to an operation amount of a steering lever. It is an object of the present invention to provide a steering device for a tracked vehicle that can always obtain a turning force according to the operation amount of a steering lever regardless of the magnitude of resistance.

(e) Means for Solving Problems The steering device for a tracked vehicle according to the present invention transmits the driving force of the drive device to the left and right crawler belts via the friction joints for the left and right sides, and the operation direction of the steering lever. In a steering device of a tracked vehicle for reducing the transmission ratio of a driving force to a crawler belt by intermittently operating a friction joint on the side, a storage means for storing a relationship between an operation amount of a steering lever and a transmission ratio of a friction joint, A driving shaft rotation detecting means and a driven shaft rotation detecting means for detecting the rotational speeds of the driving shaft and the driven shaft of the friction joint, and a transmission ratio corresponding to the operation amount of the steering lever when the steering lever is operated are read out from the storing means, and the transmission ratio Further, there is provided intermittent operation means for matching the ratio of the detection result of the driving shaft rotation detecting means of the friction joint on the operation direction side with the detection result of the driven shaft rotation detecting means.

(f) Action The present invention was made by paying attention to the fact that the size of the turning radius of the turning motion in the tracked vehicle is determined by the speed ratio of the left and right crawler belts 71 and 72 as shown in FIG. Is. That is, the speed ratio of the left and right crawler belts 71, 72 is Va.
When it is / Vb, the position O of the turning center does not change.
Generally, in a tracked vehicle, the rotation of a drive unit is decelerated and transmitted only to the crawler belt on the turning direction side, and is directly connected to the crawler belt on the opposite side. Therefore, the rotational speed ratio between the driven shaft and the driving shaft of the friction joint of the steering device is equal to the speed ratio between the crawler belt on the turning direction side and the crawler belt on the opposite side. Therefore, the turning radius of the tracked vehicle at the time of turning operation is determined by the transmission ratio of the friction joint regardless of the rotation speed of the driving shaft of the friction joint in the steering device. The magnitude of the radius of gyration during turning is proportional to the turning force, so the turning force of the tracked vehicle changes due to changes in the transmission ratio of the friction joint.

In the present invention, the transmission ratio of the friction joint is determined by the operation amount of the steering lever, and the relationship is stored in the storage means. Further, the rotational speeds of the driving shaft and the driven shaft in the friction joint are detected by the driving shaft rotating means and the driven shaft rotating means. Further, when the steering lever is operated, the intermittent operation means drives the friction joint so that the ratio of the rotational speeds of the driving shaft and the driven shaft of the friction joint matches the transmission ratio corresponding to the operation amount of the steering lever. The power transmission state changes. The rotational speed of the driven shaft in the steering device is the rotational speed of the crawler belt that is rotated under the influence of the road surface resistance, and the driven shaft rotation detection means detects the actual rotational speed of the crawler belt that is rotated by the road surface resistance.

From the above, during the turning operation, the driven shaft rotates with respect to the crawler belt on the turning direction side at a transmission ratio preset as corresponding to the operation amount of the steering lever. At this time, the driven shaft rotation detection means detects the rotation speed of the crawler belt that is rotating under the influence of road surface resistance, so that the ratio of the rotation speed between the driving shaft and the driven shaft is always stored in the storage means regardless of the road surface condition. Match the stored transmission ratio. Therefore, the speed ratio between the crawler belt on the turning direction side and the crawler belt on the opposite side becomes a value according to the operation amount of the steering lever regardless of the road surface condition. The radius of gyration and the turning force are always constant regardless of the road surface condition and the vehicle speed.

(g) Embodiment FIG. 1 is a schematic diagram showing the configuration of a steering device for a tracked vehicle that is an embodiment of the present invention.

The steering device 1 is provided between a driving shaft 4 to which rotation of a driving device (not shown) is transmitted and driven shafts 3a and 3b having driving wheels 2a and 2b for rotating crawler belts (not shown) fixed at one end. ing.
Specifically, the steering device 1 includes a clutch portion 6 and a brake portion 7, and the rotation of the driving shaft 4 is transmitted from the clutch portion 6 through the braking portion 7 to the driven shafts 3a and 3b. That is,
A clutch shaft gear 8 meshes with a driving shaft gear 5 fixed to the driving shaft 4. The clutch shaft gear 8 is frictionally engaged with the transmission gears 10a and 10b via the clutches 9a and 9b. Each of the clutches 9a and 9b is a cylinder 1
1a and 11b are provided. This cylinder 11a, 11
When pressure oil is supplied to b from a hydraulic circuit to be described later, the friction engagement state between the clutch shaft gear 8 and the transmission gears 10a and 10b is released.

The transmission gears 10a and 10b are the brake shaft gears 12a and 12
It meshes with b. The brake shaft gears 12a and 12b respectively include the brakes 13a and 13b and the intermediate gear 1.
It is equipped with 5a and 15b. Cylinders 14a and 14b are provided in the brakes 13a and 13b, respectively, and when pressure oil is supplied to the cylinders 14a and 14b from a hydraulic circuit to be described later, the brakes 13a and 13b act and the brake shaft gears 12a and 12b. Rotation is restricted. The intermediate gears 15a and 15b are driven shafts 3a and 3b.
It is meshed with the driven shaft gears 16a and 16b fixed to.

With the above configuration, the rotation of the driving shaft 4 is generated by the driving shaft gear 5, the clutch shaft gear 8, the clutches 9a and 9b, the transmission gear 10a,
10b, brake shaft gears 12a and 12b, intermediate gear 15
It is transmitted to the driven shafts 3a and 3b via a and 15b and the driven shaft gears 16a and 16b. The rotation speed of the driving shaft 4 is detected by the rotation sensor S3 which is the driving shaft rotation detecting means of the present invention, and the rotation of the driven shafts 3a and 3b is detected by the rotation sensors S1 and S2 which are also the driving shaft rotation detecting means.

FIG. 2 is a hydraulic circuit diagram of the steering device for the tracked vehicle.

Cylinders 11a, 11b and 14 included in the steering device 1
The a and 14b are connected to the pump 22 via the direction switching valves 21a and 21b. In addition, the direction switching valves 21a, 21
A switching valve 23 and a relief valve 24 are provided between b and the pump 22. The relief valve 24 keeps the pressure oil pressure in the hydraulic circuit below a set value. The switching valve 23 is an electromagnetic switching valve equipped with a solenoid SOL1.
When 1 is driven, the state becomes the position P5. The switching valve 23 guides the pressure oil in the hydraulic circuit to the tank when the solenoid SOL1 is not driven. Direction switching valve 21
Each of a and 21b is changed to the state of positions P1 and P2 and P3 and P4 by operating the steering levers 25a and 25b. The operation amounts of the steering levers 25a and 25b are detected by the volumes VR1 and VR2. Further, from the direction switching valves 21a and 21b to the cylinder 14 of the brake unit 7.
A hydraulic switch SW is provided between each of a and 14b.
1, SW2 are provided. This hydraulic switch SW
1, SW2 are cylinders 14a and 14b of the brake unit 7.
Turns on when pressure oil is supplied to.

With the above configuration, when the left steering lever 25a is operated, the direction switching valve 21a is in the position P1.
When the solenoid SOL1 is driven in this state, the pressure oil supplied from the pump 22 is applied to the cylinder 11 of the clutch unit 6.
led to a. As a result, the brake shaft gear 8 is disengaged from the left transmission gear 10a, and the rotation of the driving shaft 4 is not transmitted to the left driven shaft 3a. At this time, the rotation of the drive shaft 4 is transmitted to the driven shaft 3b via the clutch portion 6 and the brake portion 7, and the left and right drive wheels 2a, 2b are transmitted.
Causes a difference in rotation speed. This turns the vehicle body to the left. Since the crawler belt on the left side rotates as the vehicle body advances, the turning radius of the turning motion becomes relatively large. When the solenoid SOL1 is turned off, the switching valve 23 returns the pressure oil in the hydraulic circuit to the tank, so the pressure oil in the cylinder 11 flows out, and the rotation of the driving shaft 4 is transmitted to the driven shaft 3a again.

When the operation amount of the left steering lever 25a is increased, the direction switching valve 21a is in the position P2. In this state, the solenoid SOL1 is driven, and the switching valve 23 is in the position P.
In the state of 5, the pressure oil supplied from the pump 22 is supplied to both the cylinder 11a and the cylinder 14a. As a result, the engagement between the clutch shaft gear 8 and the transmission gear 10a is released, and the brake 13 is activated. Thereby, the brake shaft 12a and the intermediate shaft 15a
The braking force is supplied to the driven shaft gear 16a on the left side that meshes with, and the rotation of the drive wheel 2a on the left side stops. At this time,
The crawler belt on the left side does not rotate even when the vehicle body advances, and the turning radius of the turning motion becomes small. When the solenoid SOL1 is turned off while the direction switching valve 21a is in the position P2, the pressure oil in the cylinder 14a is returned to the tank, but the pressure oil in the cylinder 11a is affected by the check valve in the position P2. Do not return to the tank. Therefore, when the direction switching valve 21a is in the position P2, the supply of the driving force to the left driving roller wheel 2a is continuously stopped even if the solenoid SOL1 is turned off.

The above operation is the same when the right steering lever 25b is operated and the direction switching valve 21b is in the position P3 or P4, and the transmission of the driving force to the right driving wheel 2b is stopped. And the braking force is supplied.

FIG. 3 is a block diagram of a control unit of a steering device of a tracked vehicle equipped with the above steering device.

The detection data of the rotation sensors S1 to S3 and the volumes VR1 and VR2, and the ON data of the hydraulic switches SW1 and SW2 are input to the CPU 31 via the I / O interface 34. A control program for each input / output device is stored in the ROM 32, and the CPU 31 outputs control data according to this program. RAM3 at this time
Part of the memory area 3 is used as a working area. The CPU 31 outputs control data to the solenoid driver 35, and the solenoid driver 35 drives the solenoid SOL1 according to this control data.

The ROM 32 has the volumes VR1 and VR2 shown in FIG.
Output, steering device transmission ratio and solenoid SOL1
The relationship with the drive duty ratio is stored. Here, the outputs of the volumes VR1 and VR2 are the steering lever 25.
It increases or decreases in proportion to the manipulated variables of a and 25b. The CPU 31 outputs the drive duty ratio of the solenoid SOL1 according to the output values of the volumes VR1 and VR2 as control data. At the same time, the CPU 31 drives the solenoid SOL1 so that the ratio between the detection result of the rotation sensor S1 or S2 and the detection result of the rotation sensor S3 matches the transmission ratio corresponding to the output values of the volumes VR1, VR2 shown in FIG. Change the ratio. The solenoid 25
When a and 25b are operated to a substantially intermediate position in the operable range and the outputs of the volumes VR1 and VR2 become V1,
The direction switching valves 21a and 21b shown in FIG.
The brake unit 7 operates in the state of 2 or P4. This turns on the switch SW1 or SW2. The ROM 32 corresponds to the storage means of the present invention.

FIG. 5 is a flowchart showing a part of a processing procedure of the control unit of the tracked vehicle.

When the output value of the volume VR1 exceeds the minute value k (n
1), the drive duty ratio D of the solenoid SOL1 corresponding to the output value of the volume VR1 is read from the ROM 32 (n2). This minute value k constitutes a dead zone that absorbs erroneous detection of the volume VR1 due to vibration of the vehicle body or erroneous operation of the steering lever 25a. Then, it is checked whether or not the switch SW1 is turned on (n3). When the steering lever 25a is operated to the intermediate position and the output of the volume VR1 exceeds V1 and the switch SW1 is turned on, the read control data of the duty ratio D is output to the solenoid driver 35.

When the switch SW1 is not turned on, the transmission ratio R corresponding to the output value of the volume VR1 is read from the ROM 32, and the detection values of the rotation sensors S1 and S3 are read (n4). Next, the rotation sensor S1 and the rotation sensor S3
The ratio Ra of the above is compared with the transmission ratio R read from the ROM 32 (n5, n6). When the ratio Ra of the rotation sensors S1 and S3 matches the transmission ratio R, the solenoid SOL1 is drive-controlled by the duty ratio D read in n2.
When the ratio Ra of the rotation sensors S1 and S3 does not match the transmission ratio R, the duty D read in n2 is multiplied by a predetermined value d (n7).

This predetermined value d is a value of 1 or less, and the duty ratio D is made smaller than the value read from the relationship with the output value of the volume VR1 shown in FIG. This n6 → n7 is continuously performed until the ratio of the rotation sensors S1 and S3 matches the transmission ratio R, and the duty ratio D is gradually reduced. In the above, n4 to n7 are the intermittent operation means of the present invention.

As described above, according to this embodiment, the steering lever 25
When a is operated, the drive duty ratio D of the solenoid SOL1 corresponding to the output value of the volume VR1 is changed to the ROM3.
It is read from 2. When the switch SW1 is not turned on, that is, when only the clutch portion 6 is operating in the steering apparatus 1, the ratio Ra of the rotation sensors S1 and S3 is Ra.
Changes the duty ratio D of the solenoid SOL1 so as to match the transmission ratio R stored in the ROM 32 in advance. The case where the ratio Ra between the rotation sensor S1 and the rotation sensor S3 does not match the transmission ratio R means that the road surface resistance to the track is large and the track rotates slowly, that is, the rotation sensor S1.
This is the case when the detected value of is small. When the road surface resistance acting on the crawler belt is increased in this way, as shown in FIG. 6, the inclination of the ratio Ra of the rotation sensors S1 and S3 with respect to the output value of the volume VR1 is translated in parallel with the inclination with respect to the output value of the transmission ratio R. It becomes a state. When the transmission of driving force is stopped in such a situation, rotation of the crawler belt is restricted by road surface resistance, and the turning radius of the vehicle body becomes smaller than necessary, and
Excessive slippage occurs in the clutch 9a. In order to prevent this, in this embodiment, the drive duty D of the solenoid SOL1 is changed from the state shown by the solid line in FIG. 6 to the state shown by the broken line. By doing so, the state in which the clutch 9a is connected, that is, the state in which the driving force is transmitted to the crawler belt is lengthened. As a result, the crawler belt is prevented from rotating, and it is possible to prevent the radius of gyration during the turning motion from being reduced by road surface resistance. Further, excessive slippage of the clutch 9a can be prevented, and wear of the clutch 9a can be reduced.

The above processing is also performed when the right steering lever 25b is operated. Further, in the present embodiment, the duty ratio is changed in order to change the transmission state of the clutch, but even in a steering device in which pressure control is performed using a multi-plate clutch, the duty ratio is changed according to the operation amount of the steering lever. The same effect can be obtained by changing the pressure acting on the clutch so that the transmission ratio becomes different. further,
Since the driving force of the driving device is directly connected to the outer side and the crawler belt during the turning operation, the ratio of the rotational speed of the crawler belt on the turning direction side to the rotational speed of the crawler belt on the opposite side should match the preset transmission ratio. If so, the rotation sensor S3 on the driving shaft side shown in FIG. 1 can be omitted.

(h) Effect of the Invention According to the present invention, the ratio of the detection result of the prime mover rotation detection means and the detection result of the driven shaft rotation detection means during the turning operation is
The friction coupling can be intermittently operated so as to match the transmission ratio corresponding to the operation amount of the steering lever stored in advance in the storage means. As a result, the ratio between the rotational speed of the driving shaft and the rotational speed of the driven shaft is uniquely determined by the operation amount of the steering lever. During the turning operation, the rotation of the driving shaft is directly connected to the crawler belt on the opposite side of the turning direction and is transmitted. It is uniquely determined by the operation amount of the steering lever regardless of the state. As described with reference to FIG. 7, if the rotation speed ratio of the left and right crawler belts is constant, the radius of gyration during turning does not change. Therefore, regardless of the road surface condition, the radius of gyration during turning is controlled by the operation amount of the steering lever. Can be determined. For this reason, the operator can select the magnitude of the turning force only by the operation amount of the steering lever without considering the road surface condition during the turning operation, and the turning operation can be easily performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a steering system for a tracked vehicle according to an embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram of the steering system, and FIG. 3 is the steering system. Block diagram of a control unit of a tracked vehicle equipped with a device,
FIG. 4 shows an output value of a volume, a transmission ratio of a steering device, a drive duty ratio of a solenoid, an ON / OFF state of a switch, and an operation amount of a steering lever, which are stored in a ROM which constitutes a part of the control unit. FIG. 5 is a flowchart showing a part of the processing procedure of the control unit, and FIG. 6 shows the relationship between the transmission ratio and the rotation speed ratio and the solenoid drive duty ratio in the steering device. FIG. FIG. 7 is a diagram showing the relationship between the speed ratio of the left and right crawler belts and the turning radius in a general tracked vehicle including the embodiment of the present invention. 1 ... Steering device, 3a, 3b ... Driven shaft, 4 ... Driving shaft, 6 ... Clutch section, 9a, 9b ... Clutch, S1, S2 ... Rotation sensor (driven shaft rotation detecting means) S3 ... ... Rotation sensor (driving shaft rotation detection means).

Claims (1)

[Claims] 1. A driving force of a drive device is transmitted to the left and right crawler belts via separate left and right friction joints, and the friction joints on the operating direction side of the steering lever are intermittently operated to reduce the transmission ratio of the driving force to the crawler belts. In a steering device for a tracked vehicle, storage means for storing a relationship between a steering lever operation amount and a transmission ratio of a friction joint, and a driving shaft rotation detection for detecting the rotational speeds of a driving shaft and a driven shaft of the friction coupling. Means and driven shaft rotation detection means, and a transmission ratio corresponding to the operation amount of the steering lever when the steering lever is operated, is read from the storage means, and the transmission ratio and the detection result of the driving shaft rotation detection means of the friction joint on the operation direction side are used. A steering device for a tracked vehicle, comprising: an intermittent operation means for matching a ratio with a detection result of the shaft rotation detection means.