JP2001065501A - Hydraulic driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a hydraulic motor by reducing a pressure loss caused by the restriction of a servo valve without wasting an operating horse power of a hydraulic pump. SOLUTION: A hydraulic driving device which is provided with a servo valve 25 that drives and rotates a hydraulic motor 43 in response to a rotation of an electric motor 24 comprises a counterbalance valve 90. When hydraulic oil circulating between the hydraulic motor 43 and the servo valve 25 circulates in the direction of an arrow D, the counter balance valve 90 applies a back pressure to hydraulic oil which is supplied from the hydraulic motor 43 to the servo valve 25 so as to circulate hydraulic oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic drive device used for a hydraulic excavator, a crane, an asphalt crusher, a machine tool, and the like, and more particularly, to a hydraulic drive device for driving a hydraulic motor using a servo valve.

[0002]

2. Description of the Related Art Heretofore, the following technology has been known as a hydraulic circuit for controlling an electric / hydraulic servo mechanism.

In FIG. 6, reference numeral 1 denotes an operation lever capable of inputting an arbitrary operation position by changing an angle, and 2 generates a voltage (operation position signal) corresponding to the input angle of the operation lever 1 to generate a controller 3. The operation position input by the operation lever 1 is converted into an operation position signal by the operation position signal output means 2 and output to the controller 3.

The controller 3 includes a hydraulic motor 16
A feedback signal is input from a rotation speed detector 4 attached to the output unit for detecting the output rotation speed of the output unit.

A hydraulic pump 12 supplies hydraulic oil from a tank 11 to a hydraulic motor 16.
1 is supplied to the hydraulic motor 16 from the directional control valve 15
To control the flow or control the oil flow.
That is, the operation of the hydraulic motor 16 is controlled by the direction switching valve 15.

The controller 3 receives the operation position signal output from the operation position signal output means 2 and the feedback signal output from the rotation speed detector 4. The position signal and the feedback signal are compared, and the direction switching valve 15 is controlled so that the hydraulic motor 16 operates according to the operation position input by the operation lever 1. Therefore, the hydraulic motor 16 operates according to the operation position input by the operation lever 1.

The pressure of the hydraulic oil supplied from the hydraulic pump 12 is always adjusted to the maximum load pressure of the hydraulic motor 16 by the servo regulator 13 with pressure compensation and the relief valve 14 regardless of the flow rate of the hydraulic motor 16. Since it is constant, the hydraulic motor 16 can operate at any load pressure.

The servo valve 15 has a position 15A and a position 15A.
The meter-in and meter-out at two positions B have throttles, respectively. The throttles reduce the flow rate through the servo valve 15 and smoothen the flow.

[0009]

However, in the above-mentioned prior art, since an electric / hydraulic servo mechanism is used, excellent control accuracy and dynamic characteristics can be obtained. Therefore, there is a problem that the pressure loss due to the throttle is large and the operating horsepower of the hydraulic pump 12 is wasted.

Accordingly, an object of the present invention is to reduce the pressure loss due to the throttle of the servo valve and to drive the hydraulic motor without wasting the operating horsepower of the hydraulic pump.

[0011]

In order to solve the above-mentioned problems, a hydraulic drive device according to the present invention comprises an electric motor driven and rotated at a speed and a rotation amount according to an input signal, and a drive rotation member driven and rotated by a hydraulic pressure. A hydraulic oil supply means for supplying hydraulic oil for driving and rotating the drive rotation member, and a flow rate of hydraulic oil supplied from the hydraulic oil supply means being controlled and supplied to the drive rotation member, so that the rotation of the electric motor is reduced. Hydraulic oil control means for driving and rotating the drive rotation member in response to the hydraulic drive device, when the hydraulic oil flowing between the drive rotation member and the hydraulic oil control means flows in one direction, A one-way back pressure means is provided for applying a back pressure to the hydraulic oil supplied from the drive rotating member to the hydraulic oil control means to distribute the hydraulic oil.

Further, the hydraulic drive device according to claim 2 is
When the one-way back pressure unit is configured such that the hydraulic oil flowing between the drive rotation member and the hydraulic oil control unit flows in one direction, the operation is supplied from the drive rotation member to the hydraulic oil control unit. When the hydraulic oil flowing between the drive rotary member and the hydraulic oil control means flows in another direction, the hydraulic oil supplied from the hydraulic oil control means to the drive rotary member is blocked. Hydraulic oil supplied from the drive rotation member to the hydraulic oil control means when the hydraulic oil flowing between the backflow prevention means and the drive rotation member and the hydraulic oil control means flows in one direction. When the operating oil flowing between the drive rotary member and the hydraulic oil control means flows in the other direction, the hydraulic oil is supplied from the hydraulic oil control means to the drive rotary member. One that hinders the flow of hydraulic oil A flow switching means, characterized by comprising a.

Further, the hydraulic drive device according to claim 3 is
When the hydraulic fluid flowing between the valve body, the drive rotation member and the hydraulic oil control means flows in one direction, the one-way flow switching means flows from the drive rotation member to the hydraulic oil control means. A spool having a distribution position through which the supplied hydraulic oil flows, and a neutral position which obstructs the flow of the hydraulic oil, spool biasing means for biasing the spool to the neutral position, and the spool by a two-system pilot pressure. And a spool operating means for operating the hydraulic fluid control means, wherein two pilot pressures are supplied from the hydraulic oil control means to the pressure of the hydraulic oil supplied to the drive rotary member, and the pilot pressure is supplied from the drive rotary member to the hydraulic oil control means. And the pressure of the operating oil to be performed.

According to the first, second and third aspects of the present invention, when the hydraulic oil flowing between the hydraulic motor and the servo valve flows in one direction, the operation supplied from the hydraulic motor to the servo valve is performed. Since a back pressure can be applied to the oil to allow the oil to flow, when the hydraulic / motor servo mechanism is used for a winch or the like in which the hydraulic motor receives an external load in only one direction, the throttle of the servo valve can be reduced. Therefore, pressure loss due to the throttle of the servo valve can be reduced, and the hydraulic motor can be driven without wasting the operating horsepower of the hydraulic pump.

The hydraulic drive device according to claim 4 is
An electric motor that is driven and rotated at a speed and a rotation amount according to an input signal, a driving rotation member that is driven and rotated by a hydraulic pressure, a hydraulic oil supply unit that supplies hydraulic oil for driving and rotating the driving rotation member, and a hydraulic oil supply unit A hydraulic oil control unit that controls the flow rate of hydraulic oil supplied from the controller to supply the drive rotary member to the drive rotary member, thereby driving and rotating the drive rotary member in accordance with the rotation of the electric motor. A back pressure means is provided for applying a back pressure to the hydraulic oil supplied from the rotating member to the hydraulic oil control means for distribution.

Further, the hydraulic drive device according to claim 5 is
When the hydraulic pressure flowing between the drive rotation member and the hydraulic fluid control means flows in one direction,
When the hydraulic oil supplied from the drive rotary member to the hydraulic oil control means is prevented from flowing and the hydraulic oil flowing between the drive rotary member and the hydraulic oil control means flows in the other direction, the operation is stopped. First backflow prevention means for flowing hydraulic oil supplied from the oil control means to the drive rotation member, and hydraulic oil flowing between the drive rotation member and the hydraulic oil control means flow in one direction. When the hydraulic oil supplied from the hydraulic oil control means to the drive rotary member flows, when the hydraulic oil flowing between the drive rotary member and the hydraulic oil control means flows in the other direction, Second backflow prevention means for preventing the flow of hydraulic oil supplied from the drive rotation member to the hydraulic oil control means, and hydraulic oil flowing between the drive rotation member and the hydraulic oil control means in one direction. When circulating, and When the hydraulic oil flowing between the dynamic rotation member and the hydraulic oil control means flows in the other direction, a back pressure is applied to the hydraulic oil supplied from the drive rotation member to the hydraulic oil control means to cause the hydraulic oil to flow therethrough. And a bidirectional flow switching means for preventing the flow of the hydraulic oil supplied from the hydraulic oil control means to the drive rotating member.

The hydraulic drive device according to claim 6 is
The two-way flow switching means is configured to supply the hydraulic fluid from the drive rotary member to the hydraulic fluid control means when the hydraulic fluid flowing between the valve body and the drive rotary member and the hydraulic fluid control means flows in one direction. When the hydraulic oil flowing between the first flow position for flowing the hydraulic oil to be supplied and the drive rotary member and the hydraulic oil control means flows in the other direction, the hydraulic oil control is performed from the drive rotary member. A spool having a second circulation position for circulating the hydraulic oil supplied to the means, a neutral position for preventing the circulation of the hydraulic oil, a spool urging means for urging the spool to the neutral position, and two systems. Spool operating means for operating the spool by pilot pressure, wherein the pilot pressure of the two systems is controlled by a pressure of hydraulic oil supplied to the drive rotating member from the hydraulic oil control means, and And the pressure of the hydraulic fluid supplied to said hydraulic fluid control means from the member, that is composed of features.

According to the fourth, fifth and sixth aspects of the present invention, the hydraulic oil supplied to the servo valve from the hydraulic motor can always be supplied with a back pressure to allow the hydraulic oil to flow therethrough. When used, the throttle of the servo valve can be reduced. Therefore, pressure loss due to the throttle of the servo valve can be reduced, and the hydraulic motor can be driven without wasting the operating horsepower of the hydraulic pump.

The hydraulic drive device according to claim 7 is
The spool operating means includes a pilot oil throttle means for reducing a flow rate of the pilot oil for giving the pilot pressure. Thereby, the speed of the operation of the spool can be controlled, and the back pressure applied to the hydraulic oil can be controlled.

The hydraulic drive device according to claim 8 is
The spool is provided with hydraulic oil restricting means for restricting a flow rate of hydraulic oil supplied from the drive rotating member to the hydraulic oil control means. Thereby, the back pressure applied to the hydraulic oil can be controlled.

[0021]

Preferred embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment)

A hydraulic drive device according to a first embodiment of the present invention will be described with reference to FIGS.

The hydraulic drive device according to the present embodiment is a hydraulic drive device most suitable for use in a device such as a winch that receives an external load only in one direction, and the hydraulic drive device according to the present embodiment is exclusively shown in FIG. The load is applied only in the direction of arrow D shown in FIG.

First, the configuration of the hydraulic drive device according to the present embodiment will be described.

In FIG. 1 to FIG. 3, reference numeral 41 denotes a tank for storing oil; 43, a hydraulic motor as a drive rotating member driven and rotated by hydraulic pressure; and 42, a hydraulic oil for driving and rotating the hydraulic motor 43. It is a hydraulic pump as hydraulic oil supply means for supplying.

Numerals 31, 32, 33 and 34 denote signal transmission paths for transmitting electric signals.
3, 54, 55, 56, 61, 62, 63, 64, 6
Reference numerals 5, 66, and 67 denote oil passages through which the hydraulic oil flows.
4a, 45a, 57, 58, 59, 84 and 85 are pilot oil passages through which pilot oil flows.

Reference numeral 20 denotes drive rotation control means for controlling the flow rate of hydraulic oil supplied from the hydraulic pump 42 and supplying the hydraulic oil to the hydraulic motor 43 so as to cause the hydraulic motor 43 to rotate arbitrarily. The drive rotation control unit 20 includes an operation lever 21 that can input an arbitrary operation position, an operation position signal output unit 22 that generates and outputs an operation position signal corresponding to the operation position input to the operation lever 21, A central processing unit (hereinafter, simply referred to as a CPU) 23 that performs arithmetic processing on the operation position signal output from the operation position signal output unit 22 to convert the operation position signal into a drive signal and outputs the drive signal; An electric motor 24 as an electric motor driven and rotated according to the amount of rotation;
The hydraulic motor 43 controls the flow rate of hydraulic oil supplied from the
And a servo valve 25 as hydraulic oil control means for driving and rotating the hydraulic motor 43 in accordance with the rotation of the electric motor 24.

The servo valve 25 is located at the first flow position 25.
A, it is possible to move to the neutral position 25B and the second distribution position 25C.

When the pressure of the pilot oil in the pilot oil passage 44a is smaller than the set pressure, the oil passage 5
5 and the oil passage 56, and when the pressure of the pilot oil in the pilot oil passage 44a is larger than the set pressure, the oil passage 55
And the oil passage 56 communicates with the main relief valve 44. The set pressure of the main relief valve 44 is determined by the pressure of the pilot oil in the pilot oil passage 57 and the urging force of the spring 44b. 45, when the pressure of the pilot oil in the pilot oil passage 45a is smaller than the set pressure, the pilot oil passage 58 and the pilot oil passage 59 are cut off, and when the pressure of the pilot oil in the pilot oil passage 45a is larger than the set pressure. , A pilot oil passage communicating with the pilot oil passage 58, and the set pressure of the electromagnetic relief valve 45 is determined by the voltage input from the signal transmission line 33.

Reference numeral 46 denotes a mechanical motor for forcibly stopping the drive rotation of the hydraulic motor 43, and reference numeral 47 denotes a hydraulic pump 42.
Is a pump regulator that controls the flow rate of the working oil supplied by the pump.

The CPU 23 is provided with an electromagnetic relief valve 45.
And a pump regulator 47.
Voltage can be output.

Reference numeral 90 denotes the hydraulic motor 43 and the servo valve 2
When hydraulic fluid flowing between the hydraulic fluid 43 and the hydraulic fluid 43 flows in the direction of arrow D shown in FIG. When the hydraulic oil flowing between the hydraulic motor 43 and the servo valve 25 flows in the direction of arrow D shown in FIG.
When the hydraulic oil flowing from the hydraulic motor 43 to the servo valve 25 flows in the opposite direction of the arrow D shown in FIG. A check valve 70 as a backflow preventing means for flowing the hydraulic oil supplied from the hydraulic motor 43 to the hydraulic motor 43 and the hydraulic oil flowing between the hydraulic motor 43 and the servo valve 25 are moved in the direction of arrow D shown in FIG. When circulating, the hydraulic motor 4
When hydraulic fluid supplied between the hydraulic motor 43 and the servo valve 25 flows in the opposite direction of the arrow D shown in FIG. And a spool valve 80 as one-way flow switching means for preventing the flow of hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43.

The spool valve 80 includes a valve body 91 common to the check valve 70, the hydraulic motor 43 and the servo valve 25.
When the hydraulic oil flowing between the hydraulic fluid 43 and the hydraulic oil 43 flows in the direction of the arrow D shown in FIG. Spool 80 having a position 80B
And springs 82 and 83 as spool urging means for urging the spool 81 to the neutral position, and pilot oil paths 84 and 85 as spool operating means for operating the spool 81 by pilot pressure.

Reference numerals 84a and 85a denote throttles provided in the pilot oil passages 84 and 85, respectively, as pilot oil throttle means for reducing the flow rate of the pilot oil.
Reference numeral 6 denotes a throttle provided on the spool 81 and serving as hydraulic oil throttle means for reducing the flow rate of hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25.

Next, the operation of the hydraulic drive device according to this embodiment will be described.

First, the operation of the hydraulic motor 43 driven and rotated in accordance with the operation position input by the operator through the operation lever 21 will be described.

First, when the operator inputs an arbitrary operation position by changing the angle of the operation lever 21, the operation position signal output means 22 outputs an operation signal which is an electric signal according to the operation position input to the operation lever 21. A position signal is generated and output to the CPU 23 via the signal transmission path 31. Next, when the operation position signal is input to the CPU 23,
Reference numeral 23 denotes an operation position signal input from the operation position signal output means 22, and converts the operation position signal into a drive signal.
2 to the electric motor 24. Next, when a drive signal is input to the electric motor 24, the electric motor 24
The drive and rotation are performed according to the speed and the rotation amount according to the drive signal input from the PU 23. That is, the electric motor 24
Is driven and rotated in accordance with the operation position input by the operator through the operation lever 21. Finally, when the electric motor 24 is driven and rotated, the electric motor 24, the servo valve 25, and the hydraulic motor 43 constitute an electric / hydraulic servo mechanism described later. Therefore, the hydraulic motor 43 follows the driving rotation of the electric motor 24. Drive rotation.

As described above, the hydraulic motor 43 is driven and rotated in accordance with the operation position input by the operator through the operation lever 21.

The mechanical brake 46 is connected to the hydraulic motor 43
Can be stopped.

As described above, the electric motor 24,
Since the servo valve 25 and the hydraulic motor 43 constitute an electric / hydraulic servo mechanism, the hydraulic motor 43 is
The drive rotation follows the drive rotation of No. 4.

The operation of the electric / hydraulic servo mechanism will be described below.

Input angle θ of electric motor 24₁And hydraulic motor
43 output angle θ₂And the angle difference θ₃Is generated,
Not mechanical mechanism, the angle difference θ₃According to servo valve
25 ports are opened. Servo valve 25 port open
Then, the hydraulic oil is supplied to the servo valve 25 by the hydraulic pump 42.
Hydraulic oil for driving and rotating the pressure motor 43 is supplied to the tank 4.
1 through oil passages 50, 51 and 52
Therefore, hydraulic oil is supplied from the hydraulic pump 42 to the hydraulic motor 43.
The hydraulic motor 43 is driven and rotates. Hydraulic motor 4
3 is driven and rotated by a mechanical mechanism (not shown).
Angle difference θ₃Decreases. That is, the output angle θ₂Enters
Force angle θ₁If it becomes smaller, the output angle θ ₂Described above
The rotation of the hydraulic motor 43 causes the angular difference θ₃Without
And the output angle θ₂Is the input angle θ₁Bigger
Output angle θ₂Is the hydraulic motor 43 described above.
Angle difference θ₃Until it runs out
You. Therefore, the hydraulic motor 43 is provided with an electric / hydraulic servo.
The drive mechanism follows the drive rotation of the electric motor 24 by the mechanism.
It is dynamically rotated.

The CPU 23 controls the pressure of the hydraulic oil supplied from the hydraulic pump 42 to the servo valve 25.

The control of the pressure of the working oil supplied from the hydraulic pump 42 to the servo valve 25 by the CPU 23 will be described below.

When the CPU 23 outputs a voltage to the electromagnetic relief valve 45 via the signal transmission path 33, the set pressure of the electromagnetic relief valve 45 is determined by the voltage. here,
Since the pressure of the pilot oil in the pilot oil passage 58 is controlled by the electromagnetic relief valve 45 to be equal to the set pressure of the electromagnetic relief valve 45 as described later, the set pressure of the electromagnetic relief valve 45 is determined. Then, the pressure of the pilot oil in the pilot oil passage 58 is determined. The pilot oil passage 58 and the pilot oil passage 57 are in communication with each other, and the pressure of the pilot oil in the pilot oil passage 58 is equal to the pressure of the pilot oil in the pilot oil passage 57. When the pressure is determined, the pressure of the pilot oil in pilot oil passage 57 is determined. The set pressure of the main relief valve 44 depends on the pressure of the pilot oil in the pilot oil passage 57 and the spring 44b.
Of the pilot oil passage 5
When the pressure of the pilot oil in 7 is determined, the set pressure of the main relief valve 44 is determined. Here, the oil passage 55
As will be described later, the pressure of the middle hydraulic oil is controlled by the main relief valve 44 so as to be equal to the set pressure of the main relief valve 44.
When the set pressure of 4 is determined, the pressure of the hydraulic oil in the oil passage 55 is determined. The oil passage 55 is connected to the oil passage 52 via the oil passage 54.
The pressure of the hydraulic oil in the oil passage 55 and the oil passage 52
Since the pressure of the hydraulic oil in the oil passage 55 is determined, the pressure of the hydraulic oil in the oil passage 52 is determined because the pressure of the hydraulic oil in the oil passage 55 is determined. That is, when the pressure of the hydraulic oil in the oil passage 55 is determined, the pressure of the hydraulic oil supplied from the hydraulic pump 42 to the servo valve 25 is determined.

As described above, the CPU 23 determines the pressure of the hydraulic oil supplied from the hydraulic pump 42 to the servo valve 25 by outputting the voltage to the electromagnetic relief valve 45 via the signal transmission path 33. Can be. Therefore, the CPU 23 can control the pressure of the hydraulic oil supplied from the hydraulic pump 42 to the servo valve 25 by the voltage output to the electromagnetic relief valve 45 via the signal transmission path 33.

Hereinafter, control of the pressure of the pilot oil in the pilot oil passage 58 by the electromagnetic relief valve 45 will be described.

First, the case where the pressure of the pilot oil in the pilot oil passage 58 becomes larger than the set pressure of the electromagnetic relief valve 45 will be described.

When the pressure of the pilot oil in the pilot oil passage 58 becomes larger than the set pressure of the electromagnetic relief valve 45,
Since the pilot oil passage 45a communicates with the pilot oil passage 58, the pressure of the pilot oil in the pilot oil passage 45a becomes larger than the set pressure of the electromagnetic relief valve 45. When the pressure of the pilot oil in the pilot oil passage 45a becomes larger than the set pressure of the electromagnetic relief valve 45, the electromagnetic relief valve 45 communicates the pilot oil passage 58 with the pilot oil passage 59. When the pilot oil passage 58 communicates with the pilot oil passage 59, the pilot oil in the pilot oil passage 58 flows out to the tank 41 via the pilot oil passage 59 because the pilot oil passage 59 communicates with the tank 41. I do.
Here, the pilot oil always flows into the pilot oil passage 58 from the pilot oil passage 57, but the amount of the pilot oil flowing from the pilot oil passage 57 into the pilot oil passage 58 is transferred from the pilot oil passage 58 to the tank 41. Since it is less than the amount of pilot oil flowing out, the amount of pilot oil in pilot oil passage 58 decreases, and the pressure of pilot oil in pilot oil passage 58 decreases. That is, the pressure of the pilot oil in the pilot oil passage 58
If the pressure becomes larger than the set pressure, the electromagnetic relief valve 45
As a result, the pressure of the pilot oil in the pilot oil passage 58 is reduced.

Next, a case where the pressure of the pilot oil in the pilot oil passage 58 becomes smaller than the set pressure of the electromagnetic relief valve 45 will be described.

When the pressure of the pilot oil in the pilot oil passage 58 becomes smaller than the set pressure of the electromagnetic relief valve 45,
Since the pilot oil passage 45a communicates with the pilot oil passage 58, the pressure of the pilot oil in the pilot oil passage 45a becomes smaller than the set pressure of the electromagnetic relief valve 45. When the pressure of the pilot oil in the pilot oil passage 45a becomes smaller than the set pressure of the electromagnetic relief valve 45, the electromagnetic relief valve 45 shuts off the pilot oil passage 58 and the pilot oil passage 59. Pilot oil passage 58 and pilot oil passage 59
Is interrupted, the pilot oil in the pilot oil passage 58 does not flow out to the tank 41. Here, as described above, the pilot oil passage 58 always includes the pilot oil passage 5.
7, the amount of pilot oil in the pilot oil passage 58 increases, and the pressure of the pilot oil in the pilot oil passage 58 increases. That is, when the pressure of the pilot oil in the pilot oil passage 58 becomes smaller than the set pressure of the electromagnetic relief valve 45, the pressure of the pilot oil in the pilot oil passage 58 is increased by the electromagnetic relief valve 45.

As described above, when the pressure of the pilot oil in the pilot oil passage 58 becomes larger than the set pressure of the electromagnetic relief valve 45, the electromagnetic relief valve 45
When the pressure of the pilot oil in the pilot oil passage 58 is reduced, and the pressure of the pilot oil in the pilot oil passage 58 becomes smaller than the set pressure of the electromagnetic relief valve 45, the electromagnetic relief valve 45 causes the pilot oil passage The pilot oil pressure is increased. Therefore, the pressure of the pilot oil in the pilot oil passage 58 is controlled by the electromagnetic relief valve 45 so as to be equal to the set pressure of the electromagnetic relief valve 45.

Hereinafter, the control of the pressure of the hydraulic oil in the oil passage 55 by the main relief valve 44 will be described.

First, the case where the pressure of the hydraulic oil in the oil passage 55 becomes larger than the set pressure of the main relief valve 44 will be described.

When the pressure of the hydraulic oil in the oil passage 55 becomes larger than the set pressure of the main relief valve 44, the pilot oil passage 44a communicates with the oil passage 55, so that the pressure of the pilot oil in the pilot oil passage 44a is reduced. Main relief valve 44
Becomes larger than the set pressure. When the pressure of the pilot oil in the pilot oil passage 44a becomes larger than the set pressure of the main relief valve 44, the main relief valve 44 connects the oil passage 55 and the oil passage 56. When the oil passage 55 and the oil passage 56 communicate with each other, the hydraulic oil in the oil passage 55 flows out to the tank 41 via the oil passage 56 because the oil passage 56 communicates with the tank 41. Here, the hydraulic oil always flows into the oil passage 55 from the oil passage 54, but the amount of the hydraulic oil flowing into the oil passage 55 from the oil passage 54 is the amount of the hydraulic oil flowing out from the oil passage 55 to the tank 41. Since the amount is smaller than the amount, the amount of hydraulic oil in the oil passage 55 decreases,
The pressure of the hydraulic oil in the oil passage 55 decreases. That is, when the pressure of the hydraulic oil in the oil passage 55 becomes larger than the set pressure of the main relief valve 44, the pressure of the hydraulic oil in the oil passage 55 is reduced by the main relief valve 44.

Next, a case where the pressure of the hydraulic oil in the oil passage 55 becomes smaller than the set pressure of the main relief valve 44 will be described.

When the pressure of the hydraulic oil in the oil passage 55 becomes smaller than the set pressure of the main relief valve 44, the pilot oil passage 44a communicates with the oil passage 55, so that the pressure of the pilot oil in the pilot oil passage 44a becomes lower. Main relief valve 44
Becomes smaller than the set pressure. When the pressure of the pilot oil in the pilot oil passage 44a becomes smaller than the set pressure of the main relief valve 44, the main relief valve 44
And the oil passage 56 are shut off. When the oil passage 55 and the oil passage 56 are shut off, the hydraulic oil in the oil passage 55 does not flow out to the tank 41. Here, as described above, since the hydraulic oil always flows into the oil passage 55 from the oil passage 54, the amount of the hydraulic oil in the oil passage 55 increases, and the pressure of the hydraulic oil in the oil passage 55 increases. Increases. That is, when the pressure of the hydraulic oil in the oil passage 55 becomes smaller than the set pressure of the main relief valve 44, the pressure of the hydraulic oil in the oil passage 55 is increased by the main relief valve 44.

As described above, when the pressure of the hydraulic oil in the oil passage 55 becomes larger than the set pressure of the main relief valve 44, the pressure of the hydraulic oil in the oil passage 55 is reduced by the main relief valve 44. When the pressure of the hydraulic oil in the oil passage 55 becomes smaller than the set pressure of the main relief valve 44, the pressure of the hydraulic oil in the oil passage 55 is increased by the main relief valve 44. Therefore, the pressure of the hydraulic oil in the oil passage 55 is controlled by the main relief valve 44 so as to be equal to the set pressure of the main relief valve 44.

The CPU 23 also controls the flow rate of hydraulic oil supplied from the hydraulic pump 42 to the servo valve 25. That is, the flow rate of the hydraulic oil supplied from the hydraulic pump 42 to the servo valve 25 is, for example, 5 from the flow rate of the hydraulic oil required for driving the hydraulic motor 43 by the CPU 23 (hereinafter, simply referred to as a necessary flow rate). It is controlled to increase by%.

The control of the flow rate of the working oil supplied from the hydraulic pump 42 to the servo valve 25 by the CPU 23 will be described below.

The required flow rate of the hydraulic motor 43 is
3 and the stroke volume of the hydraulic motor 43. Here, the rotation speed of the hydraulic motor 43 is equal to the rotation speed of the electric motor 24 because the hydraulic motor 43 follows the electric motor 24. The stroke volume of the hydraulic motor 43 is a design value. Here, the rotation speed of the electric motor 24 is determined from the operation position signal output from the operation position signal output unit 22.

Therefore, the CPU 23 calculates the required flow rate of the hydraulic motor 43 from the operation position signal output from the operation position signal output means 22 and the stroke volume of the hydraulic motor 43 which is known in advance, and is supplied from the hydraulic pump 42. 5% higher than the calculated required flow rate of the hydraulic motor 43
The voltage is generated so as to increase, and is output to the pump regulator 47 via the signal transmission path 34. The pump regulator 47 to which the voltage has been input operates the hydraulic pump 42 by operating the pump displacement (cc / rev) according to the voltage.
Controls the flow rate of hydraulic oil supplied by

As described above, the flow rate of the working oil supplied by the hydraulic pump 42 is controlled by the CPU 23 so as to be 5% larger than the required flow rate of the hydraulic motor 43.

In the above description, the case where the flow rate of the hydraulic oil supplied from the hydraulic pump 42 is controlled to be 5% larger than the required flow rate of the hydraulic motor 43 has been described. The value is not limited to% and may be another value.

The pump regulator 47 and the CPU
With 23, the flow rate of the hydraulic oil supplied by the hydraulic pump 42 can be controlled by remote control.

The pump regulator 47 includes:
The present invention is not limited to the one shown in FIG. 1, and a hydraulic pilot system, an electromagnetic proportional system, an electric system, or the like may be used in the present invention.

Next, the operation of the counterbalance valve 90 which is a feature of the present invention will be described.

First, the servo valve 25 is moved to the first flow position 25A.
Will be described.

When the servo valve 25 is located at the first circulation position 25A, the oil passage 52 and the oil passage 61 are communicated with each other, so that the hydraulic oil is supplied from the hydraulic pump 42 to the oil passage 51, the oil passage 52, and the oil passage 61.
Is supplied to the hydraulic motor 43 via the. Hydraulic motor 43
The hydraulic oil supplied to the hydraulic fluid flows out to the oil passage 62 after the hydraulic motor 43 is driven and rotated. Here, the oil passage 62 is the oil passage 6
3 and the oil passage 65, the hydraulic oil flowing out to the oil passage 62 is supplied to the check valve 70 via the oil passage 63,
Alternatively, the oil is supplied to the spool valve 80 via the oil passage 65.

The hydraulic oil supplied to the check valve 70 via the oil passage 63 is prevented from flowing to the oil passage 64 by the check valve 70. The hydraulic oil supplied to the spool valve 80 via the oil passage 65 is supplied with the back pressure set by the spool valve 80 and then flows out to the oil passage 66 as described later. That is, the counterbalance valve 90 is
Thus, the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 is prevented from flowing, and the spool valve 80 applies back pressure to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 to flow the hydraulic oil.

The operating oil flowing out of the oil passage 66 is supplied to the servo valve 25 via the oil passage 67. Here, servo valve 2
5 is in the first circulation position 25A, the hydraulic oil supplied to the servo valve 25 via the oil passage 67 flows out to the tank 41 via the oil passage 53.

The operation of the above-described spool valve 80 for applying a back pressure to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 to distribute the hydraulic oil will be described.

First, the pressure of the working oil in the oil passage 61
The case where the pressure becomes larger than the hydraulic oil pressure in 6, 67 and 64 will be described.

When the pressure of the hydraulic oil in the oil passage 61
When the pressure becomes larger than the pressure of the hydraulic oil in 7 and 64, the oil passage 6
1 and the pilot oil passage 84, and the oil passage 64 and the pilot oil passage 85 are in communication. Therefore, the pressure of the pilot oil in the pilot oil passage 84 is also higher than the pressure of the pilot oil in the pilot oil passage 85. Become. When the pressure of the pilot oil in the pilot oil passage 84 becomes larger than the pressure of the pilot oil in the pilot oil passage 85, the spool valve 80
Moves to the circulation position 80A according to the difference between the pressure of the pilot oil in the pilot oil passage 84 and the pressure of the pilot oil in the pilot oil passage 85. Spool valve 80 is in circulation position 8
When it moves to 0A, the oil passage connecting the oil passage 65 and the oil passage 66 in the spool valve 80 has a difference between the pressure of the pilot oil in the pilot oil passage 84 and the pressure of the pilot oil in the pilot oil passage 85. Accordingly, the hydraulic oil in the oil passage 65 flows out from the oil passage 65 to the oil passage 66. Here, the spool valve 80
Is provided with a throttle 86, which applies a back pressure to the hydraulic oil flowing through the spool valve 80. That is,
The spool valve 80 applies a back pressure to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 to distribute the hydraulic oil.

Next, the pressure of the hydraulic oil in the oil passage 61
The case where the pressure becomes lower than the pressure of the working oil in 6, 67 and 64 will be described.

The pressure of the working oil in the oil passage 61 is
7 and 64, the oil passage 61 and the pilot oil passage 84 communicate with each other, and the oil passage 64 and the pilot oil passage 85 communicate with each other.
4 is also lower than the pressure of the pilot oil in the pilot oil passage 85. When the pressure of the pilot oil in the pilot oil passage 84 becomes equal to or less than the pressure of the pilot oil in the pilot oil passage 85, the spool valve 80 moves to the neutral position 8
Move to 0B. When the spool valve 80 moves to the neutral position 80B, the oil passage connecting the oil passage 65 and the oil passage 66 in the spool valve 80 closes, and the hydraulic oil in the oil passage 65 flows out of the oil passage 65 to the oil passage 66. Disappears.

The hydraulic oil in the oil passage 65 is moved from the oil passage 65 to the oil passage 6
6, the oil passage 65 is in communication with the oil passage 61 via the oil passage 62 and the hydraulic motor 43.
1 does not flow out from the oil passage 61 to the hydraulic motor 43 either. Further, hydraulic oil is supplied to the oil passage 61 from a hydraulic pump 42. Therefore, the amount of the hydraulic oil in the oil passage 61 increases, and the pressure of the hydraulic oil in the oil passage 61 increases.

When the hydraulic oil in the oil passage 65 stops flowing from the oil passage 65 to the oil passage 66, the oil passages 66, 67 and 64
The amount of hydraulic oil inside decreases, and the pressure of hydraulic oil in oil passages 66, 67 and 64 decreases.

Therefore, when the pressure of the hydraulic oil in the oil passage 61 becomes lower than the pressure of the hydraulic oil in the oil passages 66, 67 and 64, the hydraulic motor 43 stops rotating and the pressure of the hydraulic oil in the oil passage 61 is reduced. And the pressure of the hydraulic fluid in oil passages 66, 67 and 64 increases.

As described above, when the pressure of the hydraulic oil in the oil passage 61 becomes larger than the pressure of the hydraulic oil in the oil passages 66, 67 and 64, the spool valve 80 is supplied from the hydraulic motor 43 to the servo valve 25. To the hydraulic oil by applying back pressure.
When the pressure of the working oil in the oil passage 61 becomes lower than the pressure of the working oil in the oil passages 66, 67 and 64, the working oil in the oil passage 65 stops flowing from the oil passage 65 to the oil passage 66, and the oil passage 61 The difference between the pressure of the hydraulic oil in and the pressure of the hydraulic oil in oil passages 66, 67 and 64 increases.

Therefore, the spool valve 80 applies a back pressure to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 to distribute the hydraulic oil.

Next, the case where the servo valve 25 is at the neutral position 25B will be described.

When the servo valve 25 is at the neutral position 25B, the oil passage 52 is shut off from the oil passage 61 or the oil passage 67, so that the hydraulic oil is not supplied from the hydraulic pump 42 to the hydraulic motor 43. Since the oil passage 61, the oil passage 67, and the oil passage 64 communicate with each other, the pressure of the hydraulic oil in the oil passage 61 is equal to the pressure of the hydraulic oil in the oil passage 64. Here, the oil passage 61 and the pilot oil passage 84 communicate with each other, and the oil passage 64 and the pilot oil passage 8 are connected.
5 is connected to the pilot oil in the pilot oil passage 84 and the pilot oil in the pilot oil passage 85 when the pressure of the hydraulic oil in the oil passage 61 and the pressure of the hydraulic oil in the oil passage 64 are equal. Oil pressures are equal. Therefore, the pressure of the pilot oil in pilot oil passage 84
No higher than the pilot oil pressure in 5
The spool valve 80 is always at the neutral position 80 </ b> B, the oil passage connecting the oil passage 66 and the oil passage 65 in the spool valve 80 is closed, and the working oil in the oil passage 66 does not flow out from the oil passage 66 to the oil passage 65. . Further, as described above, since the hydraulic drive device according to the present embodiment receives a load exclusively in the direction of arrow D shown in FIG. 1, the hydraulic oil flows into the check valve 70 only from the oil passage 63 side. That is, the counterbalance valve 90 prevents the hydraulic oil from flowing through the spool valve 80 and the check valve 70.

Therefore, the hydraulic motor 43 stops without driving and rotating.

Next, the servo valve 25 is moved to the second flow position 25C.
Will be described.

When the servo valve 25 is at the second circulation position 25C, the oil passage 52 and the oil passage 67 are communicated with each other, so that the hydraulic oil is supplied from the hydraulic pump 42 via the oil passage 51 and the oil passage 52 to the oil passage 67. Leaked to Here, since the oil passage 67 is branched into the oil passage 66 and the oil passage 64, the operating oil flowing out of the oil passage 67 is supplied to the spool valve 80 via the oil passage 66 or the oil passage 64. Is supplied to the check valve 70 via the

The hydraulic oil supplied to the spool valve 80 via the oil passage 66 is prevented from flowing to the oil passage 65 by the spool valve 80 as described later. The hydraulic oil supplied to the check valve 70 via the oil passage 64 flows out to the oil passage 63 via the check valve 70. That is, the counterbalance valve 90 prevents the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 from flowing through the spool valve 80, and distributes the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 through the check valve 70. Let it.

The hydraulic oil that has flowed into the oil passage 63 through the check valve 70 is transmitted to the hydraulic motor 43 through the oil passage 63 and the oil passage 62.
Supplied to The hydraulic oil supplied to the hydraulic motor 43 is
After the hydraulic motor 43 is driven to rotate, the hydraulic motor 43 is supplied to the servo valve 25 via the oil passage 61. Here, since the servo valve 25 is located at the second circulation position 25C, the hydraulic oil supplied to the servo valve 25 via the oil passage 61 flows out to the tank 41 via the oil passage 53.

The operation of the above-described spool valve 80 for preventing the flow of the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 will be described below.

As described above, since the hydraulic drive device according to the present embodiment receives a load exclusively in the direction of arrow D shown in FIG. 1, the pressure of the hydraulic oil in oil passages 66, 67 and 64 is reduced by oil passage 61. Always greater than the hydraulic fluid pressure inside. The oil passage 64 and the pilot oil passage 85 communicate with each other, and the oil passage 61 and the pilot oil passage 84 communicate with each other.
The pressure of the pilot oil in the pilot oil passage 84 is always greater than the pressure of the pilot oil in the pilot oil passage 84. Therefore, the pressure of the pilot oil in pilot oil passage 84
No higher than the pilot oil pressure in 5
The spool valve 80 is always at the neutral position 80 </ b> B, the oil passage connecting the oil passage 66 and the oil passage 65 in the spool valve 80 is closed, and the working oil in the oil passage 66 does not flow out from the oil passage 66 to the oil passage 65. . That is, the spool valve 80 prevents the flow of the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43.

By the operation described above, when the hydraulic oil flowing between the hydraulic motor 43 and the servo valve 25 flows in the direction of the arrow D in FIG. The supplied hydraulic oil can be circulated by applying a back pressure. Accordingly, the conventional throttle valve 15 has four throttles (see FIG. 6), and the servo valve 25 according to the present embodiment has two throttles, namely, meter-out at the first flow position 25A and meter-in at the second flow position 25C. Thus, the pressure loss due to the throttle of the servo valve 25 is reduced, and the hydraulic motor 43 can be driven without wasting the operating horsepower of the hydraulic pump 42.

As described above, the throttle 86 applies a back pressure to the hydraulic oil flowing through the spool valve 80. This back pressure is a pressure for stopping the hydraulic motor 43, and the counter balance valve 90 controls the throttle 86 Thus, a stop pressure corresponding to the deceleration of the hydraulic motor 43 can be set.

The pressure loss due to the restriction in the servo valve 25 is greater than the pressure loss due to the restriction in the counterbalance valve 90. For example, while the pressure loss due to the restriction in the servo valve 25 is about 70 kg / cm ² , the pressure loss due to the restriction in the counterbalance valve 90 is 10 kg / c.
m ² .

The throttles 84a and 85a control the operation speed of the spool 81 by reducing the flow rate of the pilot oil for operating the spool 81. By controlling the speed of the operation of the spool 81, the throttle 84a and the throttle 85a can control the back pressure applied to the hydraulic oil by the spool valve 80.

In the hydraulic drive device according to the present embodiment, when the hydraulic motor 43 sucks air, the hydraulic motor 43 stops without running idle.

The operation of the hydraulic motor 43 stopping without idling when the hydraulic motor 43 sucks air will be described below.

The oil passage between the hydraulic pump 42 such as the oil passage 51 and the oil passage 52 and the servo valve 25 is constituted by a hydraulic hose or a pipe. If the hydraulic hose or the pipe is broken, the hydraulic motor 43 sucks air. here,
Assuming that the hydraulic drive device according to the present embodiment does not include the counterbalance valve 90, the hydraulic motor 43
Becomes idle due to the sucked air and becomes inoperable.
However, since the hydraulic drive device according to the present embodiment includes the counter balance valve 90, the hydraulic motor 43
Stops without slipping.

That is, when the hydraulic motor 43 sucks air, the difference between the pressure of the working oil in the oil passage 61 and the pressure of the working oil in the oil passage 64 decreases. Oil passage 61 and pilot oil passage 8
4 is communicated with the oil passage 64 and the pilot oil passage 85, so that the difference between the pressure of the pilot oil in the pilot oil passage 84 and the pressure of the pilot oil in the pilot oil passage 85 is reduced. Therefore, the pilot oil passage 84
The pressure of the pilot oil in the pilot oil passage does not become larger than the pressure of the pilot oil in the pilot oil passage 85, the spool valve 80 is always at the neutral position 80B, and the oil passage 66 in the spool valve 80 communicates with the oil passage 65. The closed oil passage is closed and the oil passage 66 is closed.
The working oil inside does not flow out from the oil passage 66 to the oil passage 65. Further, as described above, the hydraulic drive device according to the present embodiment receives a load exclusively in the direction of arrow D shown in FIG.
Hydraulic oil flows into the check valve 70 only from the oil passage 63 side.
That is, the counter balance valve 90 is
Thus, the flow of the hydraulic oil is hindered, and the check valve 70 hinders the flow of the hydraulic oil.

Therefore, the hydraulic motor 43 stops without running idle.

(Second Embodiment)

A hydraulic drive device according to the first embodiment of the present invention will be described with reference to FIGS.

The hydraulic drive device according to the present embodiment can be used not only for a device such as a winch that receives an external load only in one direction but also for the hydraulic drive device according to the present embodiment. Alternatively, a load may be applied in the direction of arrow D.

First, the configuration of the hydraulic drive device according to the present embodiment will be described.

4 and 5, 101, 102,
103, 104, 105, 106, 107, 108, 1
Reference numerals 09, 110, 111 and 112 denote oil passages through which hydraulic oil flows, and reference numerals 133 and 134 denote pilot oil passages through which pilot oil flows.

Reference numeral 140 denotes a counterbalance valve as a back pressure means for applying a back pressure to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 and causing the hydraulic oil to flow therethrough. When the hydraulic oil flowing between the valve 25 and the hydraulic oil flows in the direction of arrow D shown in FIG. When the hydraulic oil flowing between the two flows in the direction of the arrow U shown in FIG. 4, the check valve 121 as a first backflow prevention means for flowing the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 is provided. When the hydraulic oil flowing between the hydraulic motor 43 and the servo valve 25 flows in the direction of arrow D shown in FIG. 4, the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 flows, When the hydraulic oil flowing between the motor 43 and the servo valve 25 flows in the direction of the arrow U shown in FIG. 4, the second backflow that obstructs the flow of the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 Check valve 1 as prevention means
When the hydraulic oil flowing between the hydraulic motor 43 and the servo valve 25 flows in the direction of the arrow D shown in FIG. When flowing in the direction of arrow U shown in FIG. 4, a back pressure is applied to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 to distribute the hydraulic oil, and the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 is distributed. And a spool valve 130 as a two-way flow switching means for preventing the flow.

When the hydraulic oil flowing between the valve body (not shown) and the hydraulic motor 43 and the servo valve 25 flows in the direction of arrow D shown in FIG. When the hydraulic oil flowing between the hydraulic motor 43 and the servo valve 25 flows in the direction indicated by the arrow U in FIG. A second circulation position 130C for circulating hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25, and a neutral position 130 for preventing circulation of hydraulic oil.
B, and a spring 132 as a spool urging means for urging the spool 131 to a neutral position.
And 133, and a pilot oil passage 13 as a spool operating means for operating the spool 131 by the pilot pressure
4 and 135.

Reference numerals 134a and 135a are throttles provided in the pilot oil passages 134 and 135, respectively, as pilot oil throttle means for reducing the flow rate of the pilot oil.

Next, the operation of the hydraulic drive device according to the present embodiment will be described.

First, the operation of the hydraulic motor 43 being driven to rotate in accordance with the operation position input by the operator through the operation lever 21 is the same as in the first embodiment.

Next, the operation of the counterbalance valve 140, which is a feature of the present invention, will be described.

First, the servo valve 25 is moved to the first flow position 25A.
Will be described.

When the servo valve 25 is at the first circulation position 25A, the oil passage 52 and the oil passage 101 are in communication with each other, so that hydraulic oil is supplied from the hydraulic pump 42 through the oil passage 51 and the oil passage 52 to the oil passage 101. Leaked to Here, the oil passage 101 is
4 and the oil passage 102, the hydraulic oil flowing out to the oil passage 101 is supplied to the spool valve 130 via the oil passage 104.
Or supplied to the check valve 122 via the oil passage 102.

The hydraulic oil supplied to the spool valve 130 via the oil passage 104 is supplied to the spool valve 130 as described later.
Accordingly, circulation to the oil passage 105 is prevented. The hydraulic oil supplied to the check valve 122 via the oil passage 102 flows out to the oil passage 103 via the check valve 122. That is,
The counterbalance valve 140 prevents the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 from flowing through the spool valve 130 and allows the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 from the check valve 122 to flow.

The operating oil flowing out to the oil passage 103 via the check valve 122 is supplied to the hydraulic motor 43 via the oil passage 103 and the oil passage 106. The hydraulic oil supplied to the hydraulic motor 43 is driven by the hydraulic motor 43 to rotate, and then the oil passage 10
Outflow to 7. Here, since the oil passage 107 is branched into the oil passage 110 and the oil passage 108, the operating oil flowing out of the oil passage 107 is supplied to the check valve 121 through the oil passage 110,
Alternatively, the oil is supplied to the spool valve 130 via the oil passage 108.

The hydraulic oil supplied to the check valve 121 via the oil passage 110 is prevented from flowing to the oil passage 111 by the check valve 121. The hydraulic oil supplied to the spool valve 130 via the oil passage 108 flows out to the oil passage 109 after being provided with the back pressure set by the spool valve 130 as described later. That is, the counterbalance valve 1
Reference numeral 40 designates a check valve 121 which prevents the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 from flowing, and applies a back pressure to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 via the spool valve 130 to distribute the hydraulic oil. Let it.

The hydraulic oil that has flowed out to the oil passage 109 is
2 to the servo valve 25. Here, since the servo valve 25 is at the first circulation position 25A, the hydraulic oil supplied to the servo valve 25 via the oil passage 112 flows out to the tank 41 via the oil passage 53.

Hereinafter, the operation of the above-described spool valve 130 for preventing the flow of the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 and the operation of the spool valve 130 for the hydraulic motor 43
The function of applying a back pressure to the hydraulic oil supplied to the servo valve 25 from the controller to distribute the hydraulic oil will be described.

First, the case where the pressure of the working oil in the oil passage 102 becomes larger than the pressure of the working oil in the oil passage 111 will be described.

When the pressure of the hydraulic oil in the oil passage 102
When the pressure becomes larger than the pressure of the hydraulic oil in the inside, the oil passage 102 and the pilot oil passage 134 are communicated, and the oil passage 111 and the pilot oil passage 135 are communicated. Pilot oil passage 135
Becomes larger than the pressure of the pilot oil inside. The pressure of the pilot oil in the pilot oil passage 134
5, the spool valve 130 moves to the first circulation position 130A according to the difference between the pilot oil pressure in the pilot oil passage 134 and the pilot oil pressure in the pilot oil passage 135. I do.

When the spool valve 130 is in the first circulation position 130
When moving to A, the oil passage connecting the oil passage 104 and the oil passage 105 in the spool valve 130 is closed, and the hydraulic oil in the oil passage 104 does not flow out from the oil passage 104 to the oil passage 105. That is, the spool valve 130 is connected to the hydraulic motor 4 from the servo valve 25.
3 prevents the flow of the hydraulic oil supplied to 3.

When the spool valve 130 moves to the first circulation position 130A, the oil passage 10 in the spool valve 130
8 and the oil passage 109 are connected to the pilot oil passage 1
In response to the difference between the pressure of the pilot oil in the pilot oil path 34 and the pressure of the pilot oil in the pilot oil path 135,
The hydraulic oil inside flows out from the oil passage 108 to the oil passage 109. That is, the spool valve 130 applies a back pressure to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 to circulate the hydraulic oil.

Next, a case where the pressure of the hydraulic oil in the oil passage 102 becomes equal to or lower than the pressure of the hydraulic oil in the oil passage 111 will be described.

The pressure of the hydraulic oil in the oil passage 102
When the pressure becomes equal to or lower than the pressure of the middle hydraulic oil, the oil passage 102 and the pilot oil passage 134 communicate with each other, and the oil passage 111 and the pilot oil passage 135 communicate with each other.
4 also becomes lower than the pressure of the pilot oil in the pilot oil passage 135. Pilot oilway 134
When the pressure of the pilot oil in the pilot oil passage 135 becomes lower than the pressure of the pilot oil in the pilot oil passage 135, the spool valve 130 moves to the neutral position 130B or the second circulation position 130C. When the spool valve 130 moves to the neutral position 130B or the second circulation position 130C, the oil passage connecting the oil passage 108 and the oil passage 109 in the spool valve 130 closes, and the oil passage 1
Hydraulic oil in 08 does not flow out from oil passage 108 to oil passage 109.

When the hydraulic oil in the oil passage 108 stops flowing from the oil passage 108 to the oil passage 109, the oil passage 108
7. Since the hydraulic motor 43, the oil passage 106, the oil passage 103, and the check valve 122 communicate with the oil passage 102, the hydraulic oil in the oil passage 102 does not flow out from the oil passage 102 to the oil passage 103. . Further, hydraulic oil is supplied to the oil passage 102 from a hydraulic pump 42. Therefore, the amount of the hydraulic oil in the oil passage 102 increases, and the pressure of the hydraulic oil in the oil passage 102 increases.

Further, the hydraulic oil in the oil passage 108
When the oil no longer flows out of the oil passage 109, the amount of hydraulic oil in the oil passage 111 decreases, and the pressure of the hydraulic oil in the oil passage 111 decreases.

Therefore, when the pressure of the hydraulic oil in the oil passage 102 becomes equal to or less than the pressure of the hydraulic oil in the oil passage 111, the hydraulic motor 43 does not rotate and the pressure of the hydraulic oil in the oil passage 102 and the oil passage 111 The difference with the pressure of the medium hydraulic oil increases.

As described above, when the pressure of the hydraulic oil in the oil passage 102 becomes larger than the pressure of the hydraulic oil in the oil passage 111, the spool valve 130 causes the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43. Of the hydraulic motor 43
A back pressure is applied to the hydraulic oil supplied from the servo valve 25 to the servo valve 25 to distribute the hydraulic oil. Also, the pressure of the hydraulic oil in the oil passage 102
When the pressure becomes lower than the pressure of the hydraulic oil in the oil passage 11, the hydraulic oil in the oil passage 108 stops flowing from the oil passage 108 to the oil passage 109, and the pressure of the hydraulic oil in the oil passage 102 and the pressure of the hydraulic oil in the oil passage 111. Is increased, and the pressure of the hydraulic oil in the oil passage 102 becomes larger than the pressure of the hydraulic oil in the oil passage 111.

Therefore, the spool valve 130 prevents the hydraulic oil supplied from the servo valve 25 to the hydraulic motor 43 from flowing, and applies a back pressure to the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 to distribute the hydraulic oil.

Next, the case where the servo valve 25 is at the neutral position 25B will be described.

When the servo valve 25 is at the neutral position 25B, the oil passage 52 is shut off from the oil passage 101 or the oil passage 112, so that no hydraulic oil is supplied from the hydraulic pump 42 to the hydraulic motor 43. Also, the oil passage 102, the oil passage 101, the oil passage 1
Since the oil passage 12 and the oil passage 111 communicate with each other, the pressure of the hydraulic oil in the oil passage 102 is equal to the pressure of the hydraulic oil in the oil passage 111.
Here, since the oil passage 102 and the pilot oil passage 134 are in communication with each other, and the oil passage 111 and the pilot oil passage 135 are in communication, the pressure of the hydraulic oil in the oil passage 102 and the hydraulic oil in the oil passage 111 If the pressures are equal, the pressure of the pilot oil in pilot oil passage 134 and the pressure of the pilot oil in pilot oil passage 135 are equal. Therefore, the spool valve 130
Is always at the neutral position 130B, and the oil passage and the oil passage 10 that communicate the oil passage 105 and the oil passage 104 in the spool valve 130.
8 and the oil passage 109 are closed, the hydraulic oil in the oil passage 105 does not flow from the oil passage 105 to the oil passage 104, and the hydraulic oil in the oil passage 108 also flows from the oil passage 108 to the oil passage 109. Does not leak. Further, the check valve 122 is connected between the oil passage 102 and the oil passage 103.
The check valve 121 allows the hydraulic oil to flow only from the oil passage 111 to the oil passage 110. That is, the counterbalance valve 140 prevents the hydraulic oil from flowing through the spool valve 130, the check valve 121, and the check valve 122.

Therefore, the hydraulic motor 43 stops without driving and rotating.

Next, the servo valve 25 is moved to the second flow position 25C.
Will be described.

When the servo valve 25 is at the second circulation position 25C, the operation of the counterbalance valve 140 is
Is in the first distribution position 25A.

By the above-described operation, the counterbalance valve 140 can distribute the hydraulic oil supplied from the hydraulic motor 43 to the servo valve 25 by applying a back pressure. Therefore, the conventional throttle valve 15 has four throttles (see FIG. 6), and the servo valve 25 in the present embodiment has two throttles, namely, the meter-in at the first flow position 25A and the meter-in at the second flow position 25C. Thus, the pressure loss due to the throttle of the servo valve 25 is reduced, and the hydraulic motor 43 can be driven without wasting the operating horsepower of the hydraulic pump 42.

The pressure loss due to the restriction in the servo valve 25 is larger than the pressure loss due to the restriction in the counterbalance valve 140. For example, while the pressure loss due to the throttle in the servo valve 25 is about 70 kg / cm ² , the pressure loss due to the throttle in the counterbalance valve 140 is 10 kg / cm ^2.
/ Cm ² .

The diaphragm 134a and the diaphragm 135a are
By controlling the flow rate of the pilot oil for operating the spool 131, the operation speed of the spool 131 is controlled.
By controlling the speed of the operation of the spool 131, the stop 1
The throttle valve 34a and the throttle 135a can control the back pressure applied to the hydraulic oil by the spool valve 130.

Further, in the hydraulic drive device according to the present embodiment, when the hydraulic motor 43 sucks air, the hydraulic motor 43 stops without running idle.

Hereinafter, the operation of the hydraulic motor 43 stopping without idling when the hydraulic motor 43 sucks air will be described.

The oil passage between the hydraulic pump 42 such as the oil passage 51 and the oil passage 52 and the servo valve 25 is constituted by a hydraulic hose or a pipe. If the hydraulic hose or the pipe is broken, the hydraulic motor 43 sucks air. here,
If the hydraulic drive device according to the present embodiment does not include the counterbalance valve 140, the hydraulic motor 4
No. 3 runs idle due to the sucked air and becomes inoperable. However, since the hydraulic drive device according to the present embodiment includes the counter balance valve 140, the hydraulic motor 43 stops without running idle.

That is, when the hydraulic motor 43 sucks air, the difference between the pressure of the working oil in the oil passage 102 and the pressure of the working oil in the oil passage 111 decreases. The oil passage 102 communicates with the pilot oil passage 134, and the oil passage 111 communicates with the pilot oil passage 135.
The difference between the pressure of the pilot oil in the pilot oil and the pressure of the pilot oil in the pilot oil passage 135 becomes smaller. Therefore, the spool valve 130 is always at the neutral position 130B, and the oil passage in the spool valve 130 that communicates the oil passage 105 and the oil passage 104 and the oil passage that communicates the oil passage 108 and the oil passage 109 are closed. The hydraulic oil in 105 passes from the oil passage 105 to the oil passage 104
The hydraulic oil in the oil passage 108 does not flow out from the oil passage 108 to the oil passage 109. The check valve 122 is connected to the oil passage 10
2 through the oil passage 103 only, and the check valve 12
1 allows the hydraulic oil to flow only from the oil passage 111 to the oil passage 110. That is, the counterbalance valve 140 prevents the hydraulic oil from flowing through the spool valve 130, the check valve 121, and the check valve 122.

Therefore, the hydraulic motor 43 stops without running idle.

[0143]

According to the first, second and third aspects of the present invention, when the hydraulic oil flowing between the hydraulic motor and the servo valve flows in one direction, the hydraulic oil is supplied from the hydraulic motor to the servo valve. When the hydraulic motor is used for a winch or the like in which the hydraulic motor receives an external load only in one direction, the throttle of the servo valve can be reduced. Therefore, pressure loss due to the throttle of the servo valve can be reduced, and the hydraulic motor can be driven without wasting the operating horsepower of the hydraulic pump. Further, when the hydraulic motor sucks air, the hydraulic motor can be stopped without running idle.

According to the fourth, fifth and sixth aspects of the present invention, the hydraulic oil supplied to the servo valve from the hydraulic motor can be constantly supplied with a back pressure to allow the hydraulic oil to flow therethrough. When using the mechanism, the throttle of the servo valve can be reduced. Therefore, pressure loss due to the throttle of the servo valve can be reduced, and the hydraulic motor can be driven without wasting the operating horsepower of the hydraulic pump. Also, when the hydraulic motor sucks air,
The hydraulic motor can be stopped without idling.

Further, according to the hydraulic drive device of the present invention, the operation speed of the spool can be controlled, and the back pressure applied to the hydraulic oil can be controlled.

Further, according to the hydraulic drive device of the eighth aspect, it is possible to control the back pressure applied to the hydraulic oil.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a hydraulic drive device according to a first embodiment of the present invention.

FIG. 2 is a partial hydraulic circuit diagram of the hydraulic drive device shown in FIG.

FIG. 3 is a partial cross-sectional view of the hydraulic drive device shown in FIG.

FIG. 4 is a hydraulic circuit diagram of a hydraulic drive device according to a second embodiment of the present invention.

5 is a partial hydraulic circuit diagram of the hydraulic drive device shown in FIG.

FIG. 6 is a hydraulic circuit diagram of a conventional hydraulic drive device.

[Explanation of symbols]

 24 Electric motor (Electric motor) 43 Hydraulic motor (Drive rotating member) 42 Hydraulic pump (Hydraulic oil supply means) 25 Servo valve (Hydraulic oil control means) 90 Counter balance valve (One-way back pressure means) 70 Check valve (Backflow prevention) Means) 80 Spool valve (one-way flow switching means) 91 Valve body 80A Flow position 80B Neutral position 81 Spool 82, 83 Spring (spool biasing means) 84, 85 Pilot oil passage (spool operating means) 84a, 85a Restrictor (pilot) Oil throttle means) 86 Throttle (hydraulic oil throttle means) 140 Counterbalance valve (back pressure means) 121 Check valve (first check means) 122 Check valve (second check means) 130 Spool valve (bidirectional) Distribution switching means) 130A First distribution position 130B Neutral position 130C Second distribution position 131 Spool 1 32, 133 Spring (spool biasing means) 134, 135 Pilot oil passage (spool operating means) 134a, 135a Restriction (pilot oil restricting means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruo Kodama 1414 Goshono, Tarui-cho, Fuwa-gun, Gifu Prefecture Teijin Machinery Gifu Second Plant Co., Ltd. F-term (reference) 3H001 AA09 AB06 AB07 AC01 AD04 AE11

Claims (8)

[Claims] 1. An electric motor driven and rotated at a speed and a rotation amount according to an input signal, a driving rotary member driven and rotated by a hydraulic pressure, and a hydraulic oil supply means for supplying hydraulic oil for driving and rotating the driving rotary member. A hydraulic oil control unit that controls the flow rate of the hydraulic oil supplied from the hydraulic oil supply unit and supplies the hydraulic oil to the drive rotary member, thereby driving and rotating the drive rotary member according to the rotation of the electric motor. In the device, when the hydraulic oil flowing between the drive rotation member and the hydraulic oil control means flows in one direction, a back pressure is applied to the hydraulic oil supplied from the drive rotation member to the hydraulic oil control means. A hydraulic drive device comprising a one-way back pressure means for applying and flowing. 2. The hydraulic oil control device according to claim 1, wherein the one-way back pressure means is configured to control the hydraulic oil control means from the drive rotation member when the hydraulic oil flowing between the drive rotation member and the hydraulic oil control means flows in one direction. When the hydraulic oil flowing between the drive rotary member and the hydraulic oil control means flows in the other direction, the hydraulic oil supplied to the drive rotary member is supplied to the drive rotary member. Backflow prevention means for flowing the hydraulic oil to be supplied, and when the hydraulic oil flowing between the drive rotation member and the hydraulic oil control means flows in one direction, the drive rotation member to the hydraulic oil control means When the supplied hydraulic oil is supplied with a back pressure to cause the hydraulic oil to flow therethrough, and when the hydraulic oil flowing between the drive rotating member and the hydraulic oil control means flows in another direction, the hydraulic oil Hydraulic oil flow supplied to components Hydraulic drive system according to claim 1, characterized in that and a one-way flow switching means for hinder. 3. The method according to claim 1, wherein the one-way flow switching means is configured to: when the hydraulic oil flowing between the valve body, the drive rotation member and the hydraulic oil control means flows in one direction, A spool having a circulation position for circulating the hydraulic oil supplied to the hydraulic oil control means, a neutral position for preventing the circulation of the hydraulic oil, a spool urging means for urging the spool to the neutral position, A spool operating means for operating the spool by a pilot pressure, wherein two pilot pressures are supplied from the hydraulic oil control means to the pressure of the hydraulic oil supplied to the drive rotary member, and the drive rotary member is actuated by the drive rotary member. 3. The hydraulic drive device according to claim 2, wherein the hydraulic drive device comprises a pressure of hydraulic oil supplied to the oil control means. 4. An electric motor driven and rotated at a speed and a rotation amount according to an input signal, a driving rotary member driven and rotated by hydraulic pressure, and a hydraulic oil supply means for supplying hydraulic oil for driving and rotating the driving rotary member. A hydraulic oil control unit that controls the flow rate of the hydraulic oil supplied from the hydraulic oil supply unit and supplies the hydraulic oil to the drive rotary member, thereby driving and rotating the drive rotary member according to the rotation of the electric motor. In the apparatus, there is provided a back pressure means for applying a back pressure to the hydraulic oil supplied from the drive rotating member to the hydraulic oil control means to distribute the hydraulic oil. 5. The system according to claim 1, wherein the back pressure means supplies the hydraulic oil control means from the drive rotary member when the hydraulic oil flowing between the drive rotary member and the hydraulic oil control means flows in one direction. When the hydraulic oil flowing between the drive rotary member and the hydraulic oil control means flows in the other direction, the hydraulic oil is supplied from the hydraulic oil control means to the drive rotary member. First backflow prevention means for flowing hydraulic oil, and when the hydraulic oil flowing between the drive rotation member and the hydraulic oil control means flows in one direction, the hydraulic oil control means changes the drive rotation member When the hydraulic oil flowing between the drive rotary member and the hydraulic oil control means flows in the other direction, the hydraulic oil is supplied from the drive rotary member to the hydraulic oil control means. That obstructs the distribution of hydraulic oil Backflow prevention means, when the hydraulic oil flowing between the drive rotation member and the hydraulic oil control means flows in one direction, and between the drive rotation member and the hydraulic oil control means. When the operating oil flows in the other direction, the operating oil supplied from the drive rotating member to the operating oil control unit is supplied with a back pressure to allow the operating oil to flow, and is supplied from the operating oil control unit to the drive rotating member. The hydraulic drive device according to claim 4, further comprising: bidirectional flow switching means for preventing flow of hydraulic oil. 6. The two-way flow switching means, wherein when the hydraulic oil flowing between the valve body, the drive rotation member and the hydraulic oil control means flows in one direction, the operation from the drive rotation member is performed. A first flow position at which the hydraulic oil supplied to the oil control means flows, and a hydraulic oil flowing between the drive rotary member and the hydraulic oil control means flowing in the other direction, the drive rotary member A spool having a second circulation position for circulating the hydraulic oil supplied to the hydraulic oil control unit from the above, and a neutral position for preventing the circulation of the hydraulic oil; and a spool urging unit for urging the spool to the neutral position. And a spool operating means for operating the spool by two systems of pilot pressures, wherein the two systems of pilot pressures are pressures of hydraulic oil supplied to the drive rotary member from the hydraulic oil control means. When the hydraulic drive device according to claim 5, characterized in that it is composed, and the pressure of the hydraulic fluid supplied to said hydraulic fluid control means from said driving rotating member. 7. The system according to claim 3, wherein said spool operating means includes pilot oil restricting means for restricting a flow rate of pilot oil for providing said pilot pressure.
Or the hydraulic drive device according to 6. 8. The hydraulic pressure according to claim 3, wherein the spool includes hydraulic oil restricting means for restricting a flow rate of hydraulic oil supplied from the driving rotary member to the hydraulic oil control means. Drive.