JPS63275803A - Control device for hydraulic motor - Google Patents

Abstract

PURPOSE:To switch a hydraulic motor to low-speed side and to avoid reckless driving of a car body by detecting an angle of inclination of the car body and connecting a pilot hydraulic circuit to an oil tank when the angle of inclination exceeds a designated angle. CONSTITUTION:When a power shovel starts descending along a falling slope with a steep gradient, a spherical member 38 in an inclinometer 37 mounted on a car body is moved from a position of a reference line O-X to the O-Y side. When the angle theta of inclination of the falling slope exceeds a set value, for example, 20 deg., a reed switch S1 receives reflected rays and outputs a signal. According to the signal, a solenoid 41a of a switch valve 41 is operated to the switch valve 41 to a switching position X, whereby pressure oil in a pilot pipeline 34 is discharged to an oil tank 27 through a by-pass pipeline 40. With such discharge, a pilot valve 30 is changed from a switching position VII.VIII, and a hydraulic motor 22 is switched to low-speed side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a hydraulic motor, and more particularly to a control device for controlling drive, stop, drive direction, and drive speed of a hydraulic motor.

(Prior Art) Generally, self-propelled construction machines, especially power shovels equipped with crawlers, etc., are equipped with a hydraulic motor for driving the vehicle.
The drive speed or drive direction is controlled to ensure accurate running of the power shovel.

As a conventional control device for this type of hydraulic motor, one shown in FIG. 4, for example, is known.

In Fig. 4, 1 is a hydraulic motor;
is provided with a volume control member 2, which is made of, for example, a swash plate, and changes the stroke volume of the hydraulic motor 1 to control the drive speed. Further, high-pressure hydraulic oil from a hydraulic source 5 is supplied or cut off to the hydraulic motor 1 via the travel control valve 3 and the counterbalance valve 4, and the hydraulic motor 1 is driven or stopped. That is, when the travel control valve 3 is in the neutral position as shown in FIG. When it is switched to (2), the counterbalance valve 4 is also switched to the operating position (2) or (2), and the hydraulic oil from the hydraulic source 5 is supplied to the hydraulic motor 1, so that the hydraulic motor 1 is driven in the forward or reverse direction of the power shovel.

On the other hand, 7 is a two-speed switching valve that switches the hydraulic motor 1 between high and low speeds, and at high speed, the pilot hydraulic source 8
Pressure oil is supplied to the pilot valve 1 via the pilot hydraulic circuit 9.
0, and at low speeds, the pressure oil is bypassed to the oil tank 6 and the operating position of the pilot valve 10 is switched to V and ■, respectively. When the pilot valve 10 is switched to the operating position (2), the hydraulic fluid from the hydraulic source 5 introduced from the high pressure selection valve 12 through the pipe 11 operates the actuator 13 connected to the volume control member 2 on the left side in the figure. It is supplied to the chamber 13a, the volume control member 2 is driven rightward, the stroke volume of the hydraulic motor 1 is reduced, and the drive speed of the hydraulic motor 1 is switched to the high speed side. Furthermore, when the pilot valve IO is switched to the operating position (2), the hydraulic oil from the hydraulic source 5 is supplied to the working chamber 13b on the right side in the figure of the actuator 13, and the volume control member 2 is driven in the opposite direction to the aforementioned driving direction. As a result, the stroke volume of the hydraulic motor 1 increases, and the hydraulic motor 1 is switched to the low speed side. In this way, the hydraulic motor installed in a power excavator can be switched between forward, backward, and stopped by its control device, and can also be switched between high and low speeds while supplying the same flow of hydraulic oil to the hydraulic motor. was carried out,
As a result, the power excavator can be accurately controlled.

(Problems to be Solved by the Invention) However, in such conventional hydraulic motor control devices, the hydraulic motor is switched to the high speed side or the low speed side by operating the two-speed switching valve, so for example, If a power excavator suddenly encounters a steep downhill slope while climbing at high speed and is forced to step down, the hydraulic motor will perform a high-pressure pumping action without the operator being able to fully judge the slope's slope. , a relief valve (not shown) provided in the hydraulic circuit between the hydraulic motor and the counterbalance valve operates, causing the vehicle to run out of control without brakes. As a result, there have been problems in that the vehicle body or equipment may be damaged, and in the worst case, personal injury may occur.

Here, two types of hydraulic motors used in power excavators, etc.
As mentioned above, in the high-speed hydraulic travel drive system, the stroke volume of the hydraulic motor is switched between two stages by the driver's switching operation to control the speed of the vehicle. power is used efficiently.

Table 1 Therefore, since the vehicle body is driven at high speed when climbing on a slope with a gentle slope, in a workplace where the running slope is highly undulating,
It is inevitable that the problems described above will occur.

(Object of the Invention) Therefore, the present invention provides an inclinometer in the vehicle body, and when the inclination angle of the vehicle body exceeds a set value, the on-off valve of the bypass pipe provided in the pilot hydraulic circuit is opened and the hydraulic motor is activated. By switching to the low speed side, the purpose is to avoid the vehicle body from running out of control when descending a steep slope, thereby preventing damage to the vehicle body or equipment and injury to persons.

(Means for Solving the Problems) In order to achieve the above object, a hydraulic motor control device according to the present invention is installed in the body of a vehicle, and is rotated by being supplied with hydraulic oil from a hydraulic source by a drive hydraulic circuit. a hydraulic motor that stops when the vehicle is cut off to run and stop the vehicle; a displacement control member that is provided on the hydraulic motor and controls the stroke volume of the hydraulic motor to switch the hydraulic motor between a high speed side and a low speed side; An actuator that drives the volume control member; normally communicates the actuator with an oil tank and switches the hydraulic motor to a low speed side; when pressure oil from a pilot hydraulic pressure source is supplied, the switch is switched to supply hydraulic oil to the actuator;
A viroft valve that operates a volume control member via an actuator to switch the hydraulic motor to the high speed side and a 2-speed switching valve are installed, and the pilot pressure oil is normally bypassed to the oil tank, and by switching the 2-speed switching valve. A hydraulic motor control device comprising: a pilot hydraulic circuit for supplying pilot pressure oil to a pilot valve to switch the pilot valve; the hydraulic motor control device is mounted on the vehicle body, detects a tilt angle of the vehicle body, and adjusts the tilt angle to a set value; an inclinometer that outputs a signal when the inclinometer is exceeded; a bypass pipe that connects the pilot hydraulic circuit to the oil tank; However, an on-off valve that normally shuts off the bypass line is provided.

(Function) In the present invention, an inclinometer is provided on the vehicle body, and when the inclination angle of the vehicle body exceeds a set value, the on-off valve of the bypass pipe provided in the biloft hydraulic circuit is opened and the hydraulic motor is moved to the low speed side. can be switched to Since the vehicle body is prevented from running out of control when descending from a steep slope, damage to the vehicle body or equipment and injury to persons are prevented from occurring.

(Example) Hereinafter, the present invention will be explained based on the drawings.

First, the configuration will be explained. 1 to 3 are diagrams showing one embodiment of the present invention.

In FIG. 1, 20 is a vehicle such as a power shovel equipped with a crawler, for example, and a hydraulic motor 22 for running and stopping the vehicle 20 is equipped on a body 21 of the vehicle 2o. The hydraulic motor 22 is connected to the drive hydraulic circuit 2 shown in FIG.
It is rotated and stopped by 3. That is, in FIG. 2, the driving hydraulic circuit 23 is provided with a travel control valve 24 and a counterbalance valve 25.
By switching the travel control valve 24 and switching the counterbalance valve 25 that responds to the travel control valve 24, the hydraulic oil from the hydraulic source 26 is supplied to the hydraulic motor 22 to rotate the hydraulic motor 22, and the hydraulic oil is The oil tank 27 is bypassed and shut off, and the hydraulic motor 22 is stopped. In addition,
25a and 25b are check valves of the counterbalance valve 25, and when the travel control valve 24 is switched to the forward switching position I, the check valve 25a opens and supplies hydraulic oil to the hydraulic motor 22, and the reverse side When switched to switching position H, check valve 2
5b opens to supply hydraulic oil to the hydraulic motor 22.

The hydraulic motor 22 has a built-in volume control member 28, which is rotatably provided on a fulcrum and is made of, for example, a swash plate.The volume control member 28 is driven by an actuator 29 in the direction of arrow H in the figure. When pressed, it rotates to reduce the angle of inclination, reduce the stroke volume of the hydraulic motor 22, and switch the hydraulic motor 22 to the high speed side. Furthermore, when the actuator 29 does not operate, the volume control member 28 is pressed in the direction of arrow F in the figure by a restoring mechanism (not shown) provided in the hydraulic motor 22 and returns to its original position, increasing the stroke volume of the hydraulic motor 22. The hydraulic motor 22 is automatically switched to the low speed side.

On the other hand, 30 is a pilot valve, and the pilot valve 30 is always operated, that is, when the 2-speed switching valve 31 is switched to the switching position (3), the pressure oil of the pilot hydraulic pressure source 33 supplied via the supply pipe 32 is supplied to the oil tank. 27, and when it is cut off, it is switched to the switching position ■. The pilot valve 3o communicates the actuator 29 with the oil tank 27, and as described above, the volume control member 28 is pressed in the direction F by the restoring mechanism (not shown), and the hydraulic motor 2
2 to the low speed side. Further, when the 2-speed switching valve 31 is switched to the switching position (■), the pressure oil in the supply pipe line 32 is supplied to the pilot valve 30 via the pilot pipe line 34, and accordingly, the pilot valve 30 is switched to the switching position (■). can be switched to

Then, the hydraulic fluid of the hydraulic source 26 is supplied from the counterbalance valve 25 of the drive hydraulic circuit 23 to the pipe line 35 and the pilot valve 3.
0 to the actuator 29, the actuator 29 is driven to press the volume control member 28 in the direction of arrow H, and switches the hydraulic motor 22 to the high speed side. here,
2-speed switching valve 31, supply pipe line 32 and pilot pipe line 3
4 constitutes a pilot hydraulic circuit 36 of the pilot valve 30, in which the 2nd speed switching valve 31 is normally switched to the low speed side switching position 3 to bypass the pilot pressure oil of the pilot hydraulic pressure source 33 to the oil tank 27, and the 2nd speed switching valve 31 is normally switched to the low speed side switching position When the switching valve 31 is switched to the high-speed switching position ■, pilot pressure oil from the pilot oil pressure source 33 is supplied to the biloft valve 30 via the supply line 32, the 2-speed switching valve 31 and the pilot line 34, and the pilot valve is closed. Switch 30.

1 and 3, numeral 37 is an inclinometer attached to the vehicle body 21, and the inclinometer 37 has a spherical member 38 with a polished outer surface inside, for example, a steel ball and a transparent liquid with relatively high viscosity. , for example, a cylindrical container 3 filled with glycerin
9, and photoelectric reed switches S, , S, provided near the sealing portions at both ends of the container 39, respectively. The container 39 is made of a transparent member, such as glass, and is curved in a downwardly convex arc shape with O as the center, as shown in FIG. When the vehicle body 21 is kept horizontal by traveling on the top, the spherical member 38 is at the center of the container 39, that is, at the reference line 0.
It is attached to the vehicle body 21 at the position indicated by -X. While the vehicle 20 is running on a slope having an inclination angle of θ with respect to the horizontal plane, the spherical member 38 in FIG.
It moves to a position forming an angle of θ with respect to -X, that is, a position indicated by the O-Y line or the 0-Z line. Also, the third
In the figure, when the vehicle 20 moves forward down a slope with an inclination angle θ, the spherical member 38 moves to the position O-Y, and when the vehicle 20 moves forward up a similar slope, the spherical member 38 moves to the position O-Y. moves to the position of the 0-Z line. Furthermore, the inclination angle θ
is the set value, e.g. o-y line at 20° position and O-X
The above-mentioned reed switches S+ and Sz are respectively arranged on the line, and the spherical member 38 is connected to the reed switches S, Sz.
Alternatively, when moving to the S2 position, the light beam transmitted through the container 39 and irradiated onto the spherical member 38 is reflected by the spherical member 38, and the reed switch S1 or S2 receives the reflected light beam and connects the reed switch Sl to an electric circuit (not shown). Alternatively, S2 outputs a signal. That is, the inclinometer 37 detects the inclination angle θ of the vehicle body 21 and outputs a signal when the inclination angle θ exceeds a set value, for example, 20''. The liquid, for example, glycerin, is used to prevent the spherical member 38 from moving due to vibrations caused by the vibrations of the vehicle 20 and causing the inclinometer 37 to malfunction, and the damping effect of glycerin Vibration of the spherical member 38 is prevented by this.

Referring again to FIG. 2, the pilot line 34 of the pilot hydraulic circuit 36 is provided with a bypass line 40 that connects the pilot hydraulic circuit 36 to the oil tank 27. An on-off valve 41 is interposed in the bypass conduit 40, and a solenoid 41a of the on-off valve 41 is a reed switch S, .

Inclinometer 3 is connected to an electric circuit (not shown) into which the signal is input
When the signal No. 7 is input, the on-off valve 41 is operated against the spring 41b, and the on-off valve 41 is switched to the switching position X. Then, the bypass line 40 is communicated, the pressure oil in the pilot line 34 is discharged to the oil tank 27, the pilot valve 30 is switched to the switching position (3), and the hydraulic motor 22 is switched to the low speed side. Furthermore, when the signal from the inclinometer 37 is not input, the on-off valve 41 is automatically returned to the switching position (2) by the biasing force of the spring 41b, and the bypass pipe 4
Block 0.

Next, in FIG. 2 for explaining the operation, the travel control valve 24 is switched to the forward side switching position I, the hydraulic oil from the hydraulic source 26 is supplied to the counterbalance valve 25, and the check valve 25a is opened to supply the hydraulic oil. is supplied to the hydraulic motor 22, and the hydraulic motor 22 is driven. Then, the counterbalance valve 25 is switched to the switching position (3) by the hydraulic pressure, and the hydraulic oil discharged from the hydraulic motor 22 is discharged into the oil tank 27 through the counterbalance valve 25 and the travel control valve 24. At the same time, hydraulic oil is supplied from the counterbalance valve 25 to the pilot valve 30 through the conduit 35, and when the 2-speed switching valve 31 is switched to the high-speed side switching position V so that the hydraulic motor 22 is switched to the high-speed side, Pilot pressure oil from the pilot oil pressure source 33 is supplied to the pilot valve 30 through the pilot oil pressure circuit 36, and the pilot valve 30 is switched to the switching position (2). Then, the hydraulic oil supplied from the counterbalance valve 25 is supplied to the actuator 29 through the pilot valve 30, and presses the volume control member 28 of the hydraulic motor 22 in the H direction, so that the hydraulic motor 22 is switched to the high speed side, and the hydraulic motor 22 is switched to the high speed side. 22 drives the vehicle 20, for example, a power shovel, to travel forward at high speed.

When the excavator 20 approaches a steep downhill slope and starts descending the slope, in FIG.
When the inside of the container 39 is moved from the position of the line toward the line O-Y, and the inclination angle θ of the downward slope exceeds a set value, for example, 20 degrees, the spherical member 38 moves to the position of the line O-Y. At this time, the light beam transmitted through the container 39 and irradiated onto the spherical member 38 is reflected by the spherical member 38, and the reed switch SI receives the reflected light beam and outputs a signal to an electric circuit (not shown). In response to this signal, the electric circuit operates the solenoid 41a of the on-off valve 41 in FIG. 2, switches the on-off valve 41 to the switching position is discharged into the oil tank 27. Along with this, the pilot valve 30 is switched from the switching position ■ to the switching position ■, and the hydraulic oil in the actuator 29 is transferred to the oil tank 2.
7 and is discharged to the volume control member 28 by a restoring mechanism (not shown).
is pressed in the F direction, and the hydraulic motor 22 is switched to the low speed side. Therefore, even if the driver of the power shovel cannot determine that the inclination angle θ of the slope during dismounting exceeds the set value and the vehicle 20 is in danger of causing a runaway, the vehicle 20
is automatically switched to the low speed side, ensuring safe and accurate running of the vehicle 20.

As described above, according to this embodiment, the inclinometer 37 is provided on the vehicle body 21 of the power excavator, and when the inclination angle θ of the vehicle body 21 exceeds a set value, for example, 20'', an inclinometer 37 is provided in the pilot hydraulic circuit 36. The on-off valve 41 of the bypass pipe 40 is opened to discharge pilot pressure oil to the oil tank 27, the pilot valve 30 is switched, and the hydraulic motor 22 is switched to the low speed side.For this reason, when descending on a steep slope, the hydraulic motor 2
The braking capacity generated by the pump action of 2 increases and the vehicle body 2
1 can be avoided, so damage to the vehicle body 21 or equipment and accidents resulting in injury or death can be prevented.

Note that in this embodiment, the bypass line 40 is provided in the pilot line 34 of the pilot hydraulic circuit 36, but the bypass line 40 is not limited to this, and similar actions and effects can be obtained even if it is provided in the supply line 32. Needless to say.

Further, when the vehicle 20 climbs a slope where the inclination angle θ exceeds a set value, the hydraulic motor 22 is always switched to the low speed side where the climbing ability is large, so that the power of the hydraulic motor 22 can be used efficiently.

(Effects) According to the present invention, an inclinometer is provided in the vehicle body, and when the inclination angle of the vehicle body exceeds a set value, the on-off valve of the bypass pipe provided in the pilot hydraulic circuit is opened to move the hydraulic motor to the low speed side. is switching to. Therefore, runaway movement of the vehicle body when descending from a steep slope can be avoided. Therefore, damage to the vehicle body or equipment and injury to persons can be prevented.

[Brief explanation of the drawing]

1 to 3 are diagrams showing one embodiment of a hydraulic motor control device according to the present invention, FIG. 1 is a front view of a vehicle showing the mounting position of the inclinometer, and FIG. 2 is a hydraulic circuit diagram thereof. 3 is a sectional view showing the structure of the inclinometer, and FIG. 4 is a hydraulic circuit diagram showing a conventional hydraulic motor control device. 20...Vehicle, 21...Vehicle body, 22...Hydraulic motor, 23...Drive hydraulic circuit, 26...Hydraulic source, 27 ... Oil tank, 28 ... Volume control member, 29 ... Actuator, 30 ... Pilot valve, 31 ... Two-speed switching valve , 33... Pilot hydraulic power source, 36... Viloft hydraulic circuit, 37...
・Inclinometer, 40...Bypass pipeline, 41...Opening/closing valve.

Claims (1)

[Claims] A hydraulic motor that is installed on the body of a vehicle, rotates when hydraulic oil from a hydraulic source is supplied by a drive hydraulic circuit, and stops when the hydraulic oil is cut off to run and stop the vehicle; A volume control member that controls the stroke volume of the hydraulic motor to switch the hydraulic motor to a high speed side or a low speed side, an actuator that drives the volume control member, and normally communicates the actuator with an oil tank to switch the hydraulic motor to the low speed side. A pilot valve that switches when pressure oil from the pilot hydraulic pressure source is supplied, supplies hydraulic oil to the actuator, operates a volume control member via the actuator, and switches the hydraulic motor to the high speed side, and a two-speed switching valve. A hydraulic motor control system equipped with a pilot hydraulic circuit that normally bypasses pilot pressure oil to an oil tank and switches the pilot valve by supplying pilot pressure oil to the pilot valve by switching the two-speed switching valve. The device includes: an inclinometer attached to the vehicle body that detects the tilt angle of the vehicle body and outputs a signal when the tilt angle exceeds a set value; and a bypass pipe connecting the pilot hydraulic circuit to an oil tank. , an on-off valve that is interposed in the bypass pipe, connects the bypass pipe when a signal from an inclinometer is input, and normally shuts off the bypass pipe. Device.