JPH1182410A - Hydraulic drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic drive device capable of changing the operating characteristics of an actuator easily according to the preference of an operator. SOLUTION: A flow path resistance selector valve 55 is interposed in pilot pressure paths 52a and 52b between a first directional control valve 46 which selects the supplying direction of hydraulic oil into a first hydraulic cylinder 42 and an operating means 49 which adjusts the direction and amount for supplying pilot pressure into the first directional control valve 46. The flow path resistance selector valve 55 is provided with a plurality of flow paths of which flow path resistances which can be switched over in multiple stages are different from each other, and can set a flow resistance according to the preference of an operator. By setting the flow path resistance, for example, the response speed of the first directional control valve 46 can be set according to the operation of the first operating means 49 and thus the operating characteristics of the first hydraulic cylinder 42 can be set according to the preference of the operator.

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, and more particularly, to a hydraulic drive device used in a construction machine and capable of controlling the operation of an actuator with an operator's favorite operation feeling.

[0002]

2. Description of the Related Art FIG. 8 is a hydraulic circuit diagram showing a hydraulic drive device 1 according to a first prior art. The hydraulic drive device 1 drives an arm and a swivel of a construction machine such as a power shovel by operating an operation lever 15, 17 and an accelerator pedal (not shown) provided near the driver's seat of the construction machine. Used for The hydraulic drive device 1 basically includes a variable displacement pump 2 and a hydraulic motor 3 driven by the variable displacement pump 2.
And hydraulic cylinders 4, direction switching valves 5 and 6 for switching the supply direction of hydraulic oil to hydraulic motor 3 and hydraulic cylinder 4, respectively, and operating means 7 for switching spool positions of direction switching valves 5 and 6 by pilot pressure. , 8 are included.

The variable displacement pump 2 is rotationally driven by a prime mover (not shown) to draw hydraulic oil from a tank 10 and discharge the hydraulic oil from a discharge port 9a. The variable displacement pump 2 is provided with a tilting member 9, and the discharge amount of hydraulic oil discharged from the variable displacement pump 2 changes according to the tilt angle of the tilting member 9. Tilting member 9
Is connected to the accelerator pedal, and the operator can adjust the tilt angle of the tilt member 9 by operating the accelerator pedal with his / her foot, and adjust the discharge amount of the hydraulic oil discharged from the variable displacement pump 2. Can be adjusted. Hydraulic oil discharged from this pump is led to a passage shown by a solid line in FIG.
It is supplied to the hydraulic motor 3 and the hydraulic cylinder 4.

The direction switching valve 5 is realized by a spool valve, and switches the supply direction of the working oil supplied from the variable displacement pump 2 to the hydraulic motor 3. The pilot pressure passages 13, 14 communicate with the pressure chambers 11, 12 of the direction switching valve 5, and are connected to operation means 8 having an operation lever 15, respectively. The directional control valve 6 is realized by a spool valve similarly to the directional control valve 5, and the variable displacement pump 2
The direction of supply of hydraulic oil supplied from the hydraulic cylinder 4 to the hydraulic cylinder 4 is switched. The pilot pressure passages 20 and 21 communicate with the pressure chambers 18 and 19 of the direction switching valve 6 and are connected to the operation means 8 having the operation lever 17 respectively.

The operator operates the operating lever 17 of the operating means 8.
Is tilted from the neutral position indicated by the solid line in the direction indicated by arrow J1, the pilot pressure in one pressure chamber 19 of the directional control valve 6 increases, and conversely, the pilot pressure in the other pressure chamber 18 increases. Decrease. As a result, the spool of the directional control valve 6 moves from the neutral position shown in FIG. 8 to the right position.
When the spool of the directional control valve 6 moves to the right position, the variable displacement pump 2 communicates with the oil chamber 23 of the hydraulic cylinder 4,
The oil chamber 24 of the hydraulic cylinder 4 and the tank 10 communicate with each other. As a result, the operating oil pressure in the oil chamber 24 of the hydraulic cylinder 4 increases, and the operating oil pressure in the oil chamber 23 decreases, and the piston rod 4a of the hydraulic cylinder is displaced in the direction indicated by the arrow J2.

On the other hand, the operator operates the operation lever 17.
Is tilted from the neutral position in the direction indicated by the arrow J3 opposite to the direction of the arrow J1, the pilot pressure in the other pressure chamber 18 of the directional control valve 6 increases, and conversely, the one pressure chamber 19
The pilot pressure inside is reduced. As a result, the spool of the direction switching valve 6 moves from the neutral position to the left position. When the spool of the directional control valve 6 moves to the left position, the variable displacement pump 2 communicates with the oil chamber 24 of the hydraulic cylinder 4, and the oil chamber 23 of the hydraulic cylinder 4 communicates with the tank 10.
As a result, the operating oil pressure in the oil chamber 24 of the hydraulic cylinder 4 increases, and the operating oil pressure in the oil chamber 23 decreases, and the piston rod 4a of the hydraulic cylinder is displaced in the direction indicated by the arrow J4.

The operator operates the operating lever 1 of the operating means 7.
When the valve 5 is tilted from the neutral position in the direction of the arrow J1, the spool of the directional control valve 5 similarly moves to the right position, and the hydraulic oil is supplied from the variable displacement pump 2 to one of the ports 3a. The output shaft 3 (not shown) is driven to rotate forward. On the other hand, when the operator tilts the operation lever 15 in the direction of the arrow J2, the spool of the direction switching valve 5 similarly moves to the left position, and the hydraulic oil is supplied from the variable displacement pump 2 to the other port 3b. And the output shaft of the hydraulic motor 3 is driven in reverse rotation.

Thus, the direction switching valves 5 and 6 for switching the supply direction of the hydraulic oil to the hydraulic motor 3 and the hydraulic cylinder 4 are provided.
And pilot pressure passages 13, 14; 2 for connecting the respective operating means 7, 8 for operating the directional control valves 5, 6.
Fixed apertures 25 to 28 are interposed at 0 and 21, respectively. When the operator tilts each of the operation levers 15 and 17 by the fixed apertures 25 to 28, the operation means 7,
8, the flow rate of the pilot pressure oil guided to the directional control valves 5 and 6 is suppressed to a small value, and the spools of the directional control valves 5 and 6 displace slowly. Thus, when driving the arm and the swivel base of the construction machine, at the start and stop of the operation, the arm and the swivel base are prevented from suddenly operating, and the impact generated by starting and stopping the arm and the swivel base is reduced. Can be reduced.

[0009] However, at the site where the construction machine as described above is used, environmental conditions are changed due to changes in temporal environment such as summer and winter or day and night, and change in geographical environment such as flatland and mountainous region. The temperature is different. Since the temperature of the pilot pressure oil changes following the environmental temperature, and the viscosity of the pilot pressure oil changes accordingly, the hydraulic drive device 1 generates a difference between the temporal and geographical environmental temperatures as described above. Thereby, the responsiveness of the direction switching valves 5 and 6 corresponding to the operation of the operation levers 15 and 17 of the operation means 7 and 8, that is, the operation characteristics of the hydraulic drive device 1 changes. Therefore, if the operation characteristics of the hydraulic drive device 1 are different, the operation feeling received by the operator from the hydraulic drive device 1 is different from the operation feeling that the operator had before, and the operability is reduced. There is a problem that.

FIG. 9 is a hydraulic circuit diagram showing a hydraulic drive device 110 according to a second prior art, which is disclosed in Japanese Patent Application Laid-Open No. 2-31006. In this prior art, the main hydraulic pressure source 111 and the tank 112 are connected via a pair of main passages 113a and 113b and an actuator (not shown) such as a hydraulic motor. This main passage 1
A pilot-type directional control valve 114 is interposed midway between 13a and 113b. This pilot type directional control valve 11
4 is switched from the neutral position to the left or right switching position by the pilot pressure from the pilot valve 115, and drives the actuator in the forward or reverse direction at the switching position and stops at the neutral position. I have.

The pilot type directional control valve 114 includes a pilot chamber 116a, 116b connected to the pilot valve 115 by a pilot pressure passage, and a spool 1
And springs 117a and 117b that support the spring 18 in a neutral position. The spool 118 of the pilot type directional control valve 114 is provided with a throttle passage for connecting the pilot chambers 116a and 116b to the tank 112, respectively. In such a configuration, the pilot pressure oil supplied to one of the pilot chambers 116a or 116b to slide the spool 118 sequentially flows out to the tank 112 through the throttle passage, and the other pilot chamber 116b or the pilot The pilot pressure oil in the chamber 116a also flows out to the tank 112 through another throttle passage, so that the pilot pressure oil can be sequentially and easily replaced. That is, each pilot room 116a, 116
When the pilot pressure is supplied to b, the pilot pressure oil is returned to the tank 112 in order, and the oil liquid in the pilot pressure passage can be replaced with the oil liquid in the tank 112 having a relatively high temperature. Even in a cold region or the like, there is no problem that the viscosity of the pilot pressure oil increases and the responsiveness deteriorates.

FIG. 10 is a hydraulic circuit diagram showing a hydraulic switching valve 121 used in a hydraulic driving device according to a third prior art. About this hydraulic switching valve 121, actual fairness 5-2
No. 7865. This hydraulic switching valve 12
Reference numeral 1 denotes a second oil passage connecting the pump port P and the tank port T to the first oil passage connecting the pump port P and the cylinder port Cy of the single-acting hydraulic cylinder inside the valve case.
Oil passage. The first oil passage is closed via an ascending pilot check valve 122, and a fine oil hole 123 is formed in the ascending pilot check valve 122 so that the first oil passage is closed.
The pressure oil flowing through the oil passage is guided to the back chamber, and the back chamber is opened and closed by the tank port T via the ascending solenoid valve S1, and a check valve 124 is interposed in the second oil passage.
The second oil passage is opened / closed to the tank port T via the descending pilot check valve 125, and the descending pilot check valve 125 is provided with a fine oil hole 126 so that the hydraulic oil flowing in the second oil passage can be opened and closed. To the back room, and the back room is descending solenoid valve S2
Is opened and closed by the tank port T via the In the hydraulic pressure switching valve 121 having such a configuration, the pilot check valves 122 and 125 for opening / closing the high-pressure side oil pressure to the tank side are provided with biasing springs for urging the high-pressure side oil passage to open to the tank side. 127 and 128 are provided.

When pressure oil is supplied to the pump port P by, for example, a hydraulic pump, the pressure oil immediately after passing through the work machine angle control port F1 and the flow divider, is transferred to the external oil pressure take-out port F2 or to the external take-out switch. Pilot check valve 12 for raising and lowering through valve 129
2, 125 and the cylinder port Cy.

The back chambers of the pilot check valves 122, 125 are connected to the oil passage 1 on the tank side through fixed throttles 130, 131.
32 and 133, and solenoid valves S1 and S2 are interposed as means for inserting / closing the connection.

When the solenoid valve S1 is set to the communicating position, the pressure oil is drained from the back chamber and the pump check oil is received, the pilot check valve 122 is opened, and the pump oil passage is opened to the oil passage 132 on the tank side. When the solenoid valve S2 is set to the communication position, the pressure oil is drained from the back chamber, the pilot check valve 125 is opened by receiving the cylinder pressure oil, and the cylinder oil passage is connected to the oil passage 1 on the tank side.
Release to 33.

Since the pipeline resistance from the back chambers of the pilot check valves 122 and 125 to the oil passages 132 and 133 on the tank side is large, when the pump pressure oil is relatively low in temperature and large in viscosity, the pilot check valves 122 and 125 are used. It takes time for the pressure oil to escape from the back chamber of the vehicle, and the movement from the closed position to the open position becomes slow. However, as a countermeasure for this problem, the pilot check valves 122 and 122 for raising and lowering are used. 125 includes opposing springs 134 and 135 that resist the biasing springs 127 and 128.
Is provided to provide an auxiliary force when the pilot check valves 122 and 125 are opened. Thus, the pilot check valve 1 is not affected by the change in the viscosity of the pump pressure oil.
The hydraulic cylinder can be quickly set to a desired position by opening 22, 22 in a short time.

As described above, in the second and third prior arts described above, it is possible to prevent a delay in response due to a change in viscosity of the pilot pressure oil due to the outside air temperature, thereby preventing a change in operation characteristics. There is no contrivance to change the operation characteristics to the preference of the operator according to the individual difference or the skill level of the operator.

[0018]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic drive device in which setting of operation characteristics can be changed and an operator can control an actuator with a desired operation feeling. That is.

[0019]

According to a first aspect of the present invention, there is provided a hydraulic pressure source, an actuator driven by hydraulic pressure of hydraulic oil from the hydraulic pressure source, and a hydraulic pressure source interposed between the hydraulic pressure source and the actuator. A directional control valve for switching a supply direction of hydraulic oil from a source by a pilot pressure, and an operating means for controlling an operation of the actuator by changing a supply direction and a supply amount of the pilot pressure oil to the directional control valve by an operation of an operator And a flow path resistance switching valve interposed in the pilot pressure path connecting the direction switching valve and the operating means, and changing the flow rate of the pilot pressure oil by switching a plurality of flow paths having different flow path resistances in multiple stages. It is a hydraulic drive device characterized by including.

According to the present invention, the direction switching valve for switching the supply direction of the hydraulic oil supplied from the hydraulic source to the actuator, and the operating means for changing the supply direction and the supply amount of the pilot pressure oil for switching the direction switching valve A flow passage resistance switching valve is interposed in the pilot pressure passage connecting the flow passages. This flow path resistance switching valve has a plurality of flow paths having different flow path resistances, switches these flow paths in multiple stages according to an operator's intention, connects the flow paths to a pilot pressure passage, and a flow rate of pilot pressure oil, that is, The supply amount per unit time can be adjusted. For example, when the operator desires to reduce the response of the actuator control by the operation means, the pilot pressure passage is selected by selecting a passage having a passage resistance smaller than the passage resistance of the currently connected passage. Just connect to
Conversely, if you feel that you want to improve the responsiveness,
What is necessary is just to select a flow path having a flow path resistance greater than the flow path resistance of the currently connected flow path and connect it to the pilot pressure passage. As described above, the operation characteristics of the control operation of the actuator can be changed in accordance with the preference of the operator.
Therefore, in the configuration of the present invention, a change in the temporal environment such as summer and winter or day and night, and a change in the viscosity of the pilot pressure oil due to a difference in environmental temperature caused by a change in the geographical environment such as a flatland and a mountainous region. As a result, it is possible to prevent the operating characteristics of the hydraulic drive device from changing, and to operate the hydraulic drive device with a preferred operation feeling according to the individual differences and the skill level of the operator. In addition, since the operation characteristics can be changed, the operability is improved.

According to a second aspect of the present invention, in the configuration of the first aspect, the flow path resistance switching valve includes a first valve hole formed at a predetermined position, and a first valve hole. A second valve hole having a different flow path resistance from the first valve hole, and a second valve hole formed closer to the other axial end than the first valve hole. A third valve hole having a different flow path resistance is formed from the second valve hole, and a spool is provided in which the first to third valve holes are selectively switched to communicate with the pilot pressure passage. And

According to the present invention, the first valve hole is formed at a predetermined position of the spool provided in the flow path resistance switching valve, and the first valve hole is located on both ends in the axial direction of the spool with respect to the first valve hole. Second and third valve holes are respectively formed. Therefore, for example, when the operator feels uncomfortable with the operation feeling of the actuator in a state where the first valve hole is connected, the second or the second valve having a flow path resistance different from the flow path resistance of the first valve hole. The operation of switching to the valve hole 3 may be performed by switching the spool of the flow path resistance switching valve to one end or the other end in the axial direction of the spool by one step, and the displacement of the spool is as small as possible. And the responsiveness of the flow path resistance switching can be improved.

According to a third aspect of the present invention, in the configuration of the second aspect, the spool includes first to third
And another valve hole group formed adjacent to the one valve hole group in the axial direction and displaced in the circumferential direction.

According to the present invention, the size of the flow path resistance switching valve can be reduced. That is, as described in claim 2, the one valve hole group is configured by arranging the first to third valve holes in a straight line along the axial direction of the spool. These first to third valve holes correspond to a pair of ports of an inlet port and an outlet port. The other valve hole group adjacent to this one valve hole group in the axial direction of the spool and corresponding to another pair of ports different from the one pair of ports is the same as the first to third valve hole groups. Are arranged in a straight line along the axial direction of the spool, and are arranged at positions shifted from the respective valve holes of the one valve hole group in the circumferential direction of the spool.

Therefore, in the configuration of the present invention, as compared with the configuration in which the first to third valve holes on the opposite sides of the one and other valve hole groups are arranged on the same straight line, the adjacent inlet sides or the adjacent ones are different. The distance required to eliminate the problem of interference between adjacent ports on the outlet side can be secured not only in the axial direction but also in the circumferential direction, so the axial length of the spool is made as small as possible. Thus, the flow path resistance switching valve can be downsized.

[0026]

FIG. 1 is a hydraulic circuit diagram showing a hydraulic drive device 41 according to an embodiment of the present invention. The hydraulic drive device 41 is provided in a construction machine realized by a power shovel or the like, and includes first and second hydraulic cylinders 42 and 43, which are actuators, and a hydraulic motor 44.
Is controlled by the operation of the operator.

The hydraulic drive unit 41 includes a variable displacement pump 45 which is a hydraulic pressure source and the first and second hydraulic pumps which are driven by hydraulic pressure of hydraulic fluid from the variable displacement pump 45.
Hydraulic cylinders 42 and 43 and a hydraulic motor 44, first to third directional switching valves 46 to 48 for switching the supply direction of hydraulic oil from the variable displacement pump 45, and first to third directional switching valves 46 to 48;
The supply direction and supply amount of the pilot pressure oil to the directional control valves 46 to 48 are changed by the operation of the operator, and the first and second hydraulic cylinders 42 and 43 and the hydraulic motor 44 are changed.
First to third operation means 49 to 51 for controlling the operation of
And the first to third directional control valves 46 to 48 and the first to third
Pilot pressure passages 52a, 52b; 53a, 53b; 54a,
And a flow path resistance switching valve 55 interposed in common with 54b.

The variable displacement pump 45 is realized by, for example, a swash plate type piston pump. When the input shaft is driven to rotate by a motor (not shown), the hydraulic oil in the tank 56 is sucked and the hydraulic oil is discharged from the discharge port 57. I do.
The discharge amount of the discharged hydraulic oil is zero when the tilting member 58 is disposed at a predetermined reference position, and changes according to the tilt angle from the reference position. The tilting member 58 is connected to an accelerator pedal arranged near the driver's seat of the construction machine, and the operator can operate the variable displacement pump 45 by foot.
Adjust the discharge amount of hydraulic oil discharged from.

First and second hydraulic cylinders 42, 43
Is a double-acting hydraulic cylinder, and the cylinder tube 5
9 and 60 and piston rods 61 and 62, respectively. Each pressure chamber 63 in each cylinder tube 59, 60
The first and second main passages 65a, 65b; 66a, 66b are connected to a, 63b; 64a, 64b, respectively. The cylinder tube 59 of the first hydraulic cylinder 42 is
For example, the piston rod 61 is connected to a construction machine main body including a driver's seat of the construction machine, and the piston rod 61 is connected to a boom swingably supported by the construction machine main body. The cylinder tube 60 of the second hydraulic cylinder 43 is connected to, for example, the boom, and the piston rod 62 is
The boom is connected to an arm swingably supported by the boom.

The hydraulic motor 44 is realized by, for example, a swash plate type piston motor, and has one and the other ports 6.
Third main passages 68a and 68b are connected to 7a and 67b, respectively. When hydraulic oil is supplied from the one port 67a or the other port 67b, an output shaft (not shown) is rotationally driven by the supply pressure, and the hydraulic oil is discharged from the other port 67b or the one port 67a. The output shaft is connected to, for example, a turning shaft of a swivel provided on a construction machine so as to be rotatable around a vertical axis. In another embodiment, the output shaft may be connected to a traveling shaft of a traveling device on which a swivel is mounted. The rotation direction and the number of rotations of the output shaft of the hydraulic motor 44 change according to the supply direction and the supply amount per unit time of the hydraulic oil supplied from one or the other port 67a, 67b.

The first to third directional control valves 46 to 48 are 6-port, 3-position control valves. The variable displacement pump 45
Communicates with the tank 76 through the passage 69. In this passage 69, first to third directional switching valves 46 to 48 are interposed. Further, the variable displacement pump 45 in the passage 69 and the first to third
A first supply passage 70 communicates with the directional control valves 46 to 48, and the first supply passage 70 has a check valve 71 in the middle, and is connected to the first directional control valve 46 to be variable. Hydraulic oil is supplied from the positive displacement pump 45.

The second directional control valve 47 is connected to a second supply passage 73 having a check valve 72, and is supplied with hydraulic oil discharged from the variable displacement pump 45. Similarly the third
A third supply passage 75 having a check valve 74 is connected to the direction switching valve 48, and hydraulic oil is supplied from the variable displacement pump 45.

The above-described first to third directional control valves 46 to 48
, The first to third main passages 65a, 65b;
6a, 66b; 68a, 68b are respectively connected, and the first to third return passages 77 to
79 are respectively connected.

The pilot pressure chamber 80 of the first directional control valve 46
a, 80b have first pilot pressure passages 52a, 52b.
Are connected to each other and communicate with the first operation means 49. The first operating means 49 is realized by a pilot valve, for example, and changes the supply direction and the supply amount of the pilot pressure oil in accordance with the operation direction and the operation amount of the operation lever 81 to change the position of the spool of the first direction switching valve 46. Can be switched. In the same manner, the pilot pressure passages 53a, 53a,
53b; 54a and 54b are connected to each other;
The position of each spool of the second and third operation means 50, 51 can be switched by changing the pilot pressure according to the operation direction and the operation amount of the operation levers 82, 83 of the 51.

The flow path resistance switching valve 55 is a 12-port, 3-position type electromagnetic valve combined with pilot pressure.
It has electromagnetic coils 84a and 84b and a spool, respectively. When both of the electromagnetic coils 84a and 84b are demagnetized, the pressure in the pilot pressure chambers at both ends of the spool is the same, and the spool is in the neutral position by the spring force of the springs 85a and 85b as shown in FIG. Will be retained.
Each pilot pressure passage 52a, 52b; 53a, 53b;
54a and 54b are connected to respective ports of the flow path resistance switching valve 55.

In such a configuration, the first operating means 4
9, the pressure chambers 8 of the first directional control valve 96 are in a state in which the operating lever 81 is disposed at a neutral position indicated by a solid line in FIG.
0a and 80b are the same pressure, in this embodiment the tank pressure,
The directional control valve 96 is in the neutral position and the first supply passage 70
Is shut off from both the main passages 65a and 65b. In this state, the hydraulic oil from the variable displacement pump 45 is guided to the tank 76.

When the operating lever 81 is tilted from the neutral position in the direction indicated by the arrow A1, the pressure in one pilot pressure chamber 80a of the first directional control valve 46 increases and the pressure in the other pilot pressure chamber 80b increases. The pressure decreases. As a result, the spool of the first directional control valve 46 is displaced in the direction indicated by the arrow B1, and the first supply passage 70 and the other first main passage 6 are displaced.
5b. In this state, when the tilting member 58 of the variable displacement pump 45 is tilted from a predetermined reference position,
The hydraulic oil discharged from the discharge port 57 is supplied to the other pressure chamber 6 of the first hydraulic cylinder 42 through the first directional control valve 46.
3b. In addition, the first main passage 65a and the first return passage 77 communicate with each other, whereby the first hydraulic cylinder 42
The hydraulic oil in one of the pressure chambers 63a is guided to the tank 76. Thereby, each pressure chamber 63 of the first hydraulic cylinder 42
The pressure difference of the hydraulic oil in a and 63b occurs, and the piston rod 61 is displaced in the direction indicated by the arrow C1.

Conversely, when the operating lever 81 of the first operating means 49 is tilted in the direction of arrow A2, the spool of the first directional control valve 46 is displaced in the direction of arrow B2 opposite to the direction of arrow B1. . As a result, the first supply passage 70 and one of the first
The hydraulic oil discharged from the variable displacement pump 45 through the communication with the main passage 65a is supplied to the first hydraulic cylinder 42
Flows into one pressure chamber 63a and the other pressure chamber 6a.
The hydraulic oil in 3b is guided to the tank 76. As a result, the piston rod 61 of the first hydraulic cylinder 42 has an arrow C2.
Is displaced in the direction indicated by.

The piston rod 6 of the first hydraulic cylinder 42
The displacement speed in the direction of the arrow C1 or C2 changes according to the tilt angle of the tilting member 58 of the variable displacement pump 45 from the reference position. Although the piston rod 62 of the second hydraulic cylinder 43 is controlled by operating the operating lever 82 provided in the second operating means 50, the operation of the operating lever 82 and the piston rod 62 of the second hydraulic cylinder 43 are controlled. The relationship with the operation is almost the same as the relationship between the operation lever 81 of the first operation means 49 and the piston rod 61 of the first hydraulic cylinder 42, and the description is omitted because they overlap.

When the operating lever 83 provided on the third operating means 51 is tilted in the direction indicated by the arrow A1, the spool of the third directional switching valve 48 is connected to the first and second directional switching valves 46 and 47 described above. Similarly, it is displaced in the direction indicated by arrow B1. Thus, the third supply passage 75 communicates with the other third main passage 68b, and the one third main passage 68a communicates with the third return passage 79. The hydraulic oil discharged from the discharge port 57 of the variable displacement pump 45 in this state is as follows:
Inflow from the other port 67b of the hydraulic motor 44 via the third direction switching valve 48, the output shaft (not shown) of the hydraulic motor 44 is positively rotated in the direction of arrow D1, and one port 67a
Is discharged from The discharged hydraulic oil is supplied to the third
The liquid is again guided to the third directional control valve 48 via the main passage 68 a and discharged into the tank 76 via the third return passage 79.

Conversely, the operation lever 8 of the third operation means 51
3 is tilted in the direction indicated by the arrow A2 opposite to the direction of the arrow A1, the spool of the third switching valve 48 is displaced in the direction of the arrow B2, and the third supply passage 75 and one of the third main passages are displaced. 68a
And the other third main passage 68b communicates with the third return passage 79. In this state, the hydraulic oil discharged from the variable displacement pump 45 flows in from one port 67a of the hydraulic motor 44 and is discharged from the other port 67b. In this state, the output shaft of the hydraulic motor 44 is indicated by an arrow D.
Reverse rotation in two directions. The rotation speed of the output shaft of the hydraulic motor 44 changes according to the tilt angle of the tilting member 58 of the variable displacement pump 45 from the reference position.

In the embodiment of the present invention, the response performance of the first and second hydraulic cylinders 42 and 43 and the hydraulic motor 44 to the operation of each of the operating levers 81 to 83 of the first to third operating means 49 to 51 is as follows. It can be changed by switching the spool position of the flow path resistance switching valve 55. The flow path resistance switching valve 55 has a plurality of flow paths having different flow path resistances that are switched in multiple stages. This switching of the flow path is performed by exciting one of the electromagnetic coil 84a and the other electromagnetic coil 84b.

One and the other electromagnetic coils 84a, 84
In a state in which both b are demagnetized, the spool of the flow path resistance switching valve 55 is held at the neutral position by the spring forces of the springs 85a and 85b as shown in FIG. When one of the electromagnetic coils 84a is excited in this state, the spool of the flow path resistance switching valve 55 is displaced in the direction indicated by the arrow E1, and the flow path resistance becomes smaller than the neutral position. As a result, the response speed to the operation of each of the operation levers 81 to 83 is slower than in the neutral state. Conversely, when the other electromagnetic coil 84b is excited and the one electromagnetic coil 84a is demagnetized, the spool of the flow path resistance switching valve 55 is displaced in the direction indicated by the arrow E2, and the flow path resistance further decreases. The response speed to the operation of each of the operation levers 81 to 83 is further reduced.

As described above, in the embodiment of the present invention,
1st and 2nd for operation of each operation lever 81-83
The response speed of the hydraulic cylinders 42 and 43 and the hydraulic motor 44 can be easily changed. That is, even if the viscosity of the pilot pressure oil changes due to a change in the outside air temperature,
The hydraulic cylinder 42,
The operating characteristics can be easily set so that the hydraulic motor 43 and the hydraulic motor 44, and thus the hydraulic drive device 1 can be operated.

FIG. 2 is a partial sectional view showing the flow path resistance switching valve 55, FIG. 3 is a perspective view of a spool 89 of the flow path resistance switching valve 55, and FIG. 4 is a sectional line IV-IV of FIG. 5 is a cross-sectional view taken along line VV of FIG. 2. FIG. 6 is a partial bottom view of the flow path resistance switching valve 55 as viewed from below in FIG. 2, and FIG. 7 is a plan view of the flow path resistance switching valve 55 as viewed from above in FIG. FIG. 7 shows the operation unit 90 in a simplified manner.

The flow path resistance switching valve 55 includes a valve body 88, a spool 89, and an operation section 90. The valve body 88 has a rectangular parallelepiped shape, and has a plurality (1 in this embodiment).
2) Ports 91a to 91f; The port 91a and the port 92a form a pair, and are connected to the first directional control valve 46 and the first operating means 49.
And is connected to the pilot pressure passage 52a on the side, thereby forming one flow passage. Each of the other ports 91b to 91f;
The same applies to 92b to 92f, that is, FIGS.
Ports having the same reference number suffix of each port shown in FIG. 7 form a pair, and each pilot pressure passage 52b;
53a, 53b; 54a, 54b, respectively.

The spool 89 has a substantially columnar shape.
The axis G1 of the spool 89 is inserted into the shaft hole 88a of the valve body 88.
Are slidably arranged in a direction along the line. This spool 89
Each of the ports 91a to 91a forming the pair of the valve body 88.
f; a plurality of valve hole groups 93a to 93f respectively corresponding to 92a to 92f are provided. These valve hole groups 93a-
93f is a plurality of (three in this embodiment) valve holes 9
4 to 96. Of the valve holes 94 to 96, throttles 151 and 152 are provided in the valve holes 95 and 96, respectively. One port 91a-91f, the other port 92a-92
When any one of f and the valve hole groups 93a to 93f is indicated, the subscripts a to f of the respective reference numerals 91, 92, 93
May be omitted.

The first valve hole 94 is formed at a predetermined position of the spool 89. Specifically, the spool 89
In the neutral position as shown in FIG. 2,
The spool 89 is formed at a position corresponding to each of the ports 91 and 92 forming the pair. The flow path resistance of the first valve hole 94 is:
For example, 1.0 is selected. The second valve hole 95 is provided with the throttle 1
The first valve hole 94 has a flow resistance different from that of the first valve hole 94, and is formed closer to one end 89 a of the spool 89 in the axial direction than the first valve hole 94. The flow path resistance of the second valve hole 95 is set to, for example, 0.8 with respect to the first valve hole 94 by the throttle 151. The third valve hole 96 is provided with the throttle 15
2, the first and second valve holes 94 and 95 have flow resistances different from those of the first and second valve holes 94, and are formed closer to the other end 89 b of the spool 89 in the axial direction than the first valve hole 94. The flow path resistance of the third valve hole 96 is, for example, 0.1 while the flow resistance of the first valve hole 94 is 1.0 due to the restriction 152.
Selected as 6. Therefore, in this embodiment, the “flow path resistance”
Is the degree of relative difficulty between the first to third valve holes 94 to 96 caused mainly by the throttles 151 and 152, and is determined by the opening degrees and lengths of the throttles 151 and 152. Things.

As described above, the second and third valve holes 95 and 96 having different flow path resistances are provided on both ends 89a and 89b of the first valve hole 94 in the axial direction of the spool 89, respectively. When the user switches the operation characteristics as described above, the second and third valve holes 95,
96, the spool 89
Can be reduced as much as possible in the axial direction. As a result, it is possible to improve the responsiveness of the flow path resistance switching to the switching operation of the operation characteristic by the operator.

The first having the axis G2 shown in FIG.
To the third valve hole 94 to 96. The valve hole group 93 includes a spool 89 with respect to an axis G3 of each valve hole of another adjacent valve hole group at an interval of an axial distance L1 of the spool 89. Makes an angle θ around the axis G1 of the spool 89, whereby the spool 89 is disposed at a position shifted by a distance L2 in the circumferential direction of the spool 89.
The angle θ is selected, for example, to 90 degrees. In this way, the axes G2, G3 of the respective valve holes of the adjacent valve hole group are mutually at an angle θ.
In this configuration, one of the adjacent ports 91 is compared with the configuration in which the valve holes of each valve hole group 93 are arranged on the same straight line.
A sufficient distance required to prevent a problem that the ports 92 or the other ports 92 interfere with each other can be sufficiently secured, whereby the axial length of the spool 89 can be reduced as much as possible. Therefore, the size of the flow path resistance switching valve 55 can be reduced. In particular, by selecting the angle θ at 90 degrees as in the present embodiment, such an effect can be exhibited most.

The driving operation of the spool 89 is performed by a pair of operating portions 90 fixed to both ends of the axial hole 88a of the valve body 88 in the center axis direction. A pilot pressure source (not shown) and a tank (not shown) are connected to the electromagnetic solenoid 86 of each of the operation units 90. The pilot pressure oil flowing into the operation unit 90 from the pilot pressure source and the operation unit 90
The back pressure oil flowing out of the tank into the tank passes through an oil passage 97.
The pilot pressure oil guided from the pilot pressure source to oil passage 97 is guided to pilot pressure chamber 100 via pilot chamber port 98 and throttle 99. Each pilot pressure chamber 10
0, both ends 89a, 89b in the axial direction of the spool 89
The springs 85a and 85b, which are elastic members, and the spring receiving pieces 102 fitted to both ends 89a and 89b in the axial direction of the spool 89 are stored, respectively. Spring 85
a and 85b are arranged such that one end in the axial direction is the pilot pressure chamber 1
The spool 89 abuts on the side wall 103 and applies a spring force in a direction away from the side wall 103 via both ends 89 a and 89 b of the spool 89 in the axial direction via the spring receiving piece 102. When the pressure in each pilot pressure chamber 100 is the same (tank pressure), the spool 89 is actuated by the spring force of the springs 85a and 85b.
Is held in the neutral position.

The electromagnetic solenoid unit 86 includes the electromagnetic coils 84a and 84b, switches 105a and 105b that are electrically connected to switches and a battery provided on an operation panel on the driver's seat of the construction machine, the pilot pressure source and the tank. And a plunger (not shown) having a valve body for communicating / blocking the oil passage 97 with the oil passage 97.

With the spool 89 in the neutral position, the operator operates the switch to excite the electromagnetic coil 84a of one of the electromagnetic solenoids 86 disposed on the one end 89a of the spool 89 in the axial direction. Then, the pressure in the pilot pressure chamber 100 at the one end 89a in the axial direction increases, whereby the end face 106 of the spool 89 serves as a pressure receiving surface and the spring 8 in the pilot pressure chamber 100b on the other side.
The spool 89 is displaced in the direction of the arrow E1 against the spring force of 5b, and the other end surface 106b of the spool 89 contacts the side wall 103 of the pilot pressure chamber 100b. The pilot pressure oil in the other pilot pressure chamber 100b is
9a is led to the tank via the pilot chamber port 98 and the oil passage 97. In this state, each of the ports 91,
The reference numerals 92 communicate with each other through the second valve holes 95.

Conversely, when the operator operates the switch to demagnetize one electromagnetic coil 84a and excite the other electromagnetic coil 84b, the other pilot pressure chamber 100b
The spool 89 is displaced in the direction of arrow E2, and the end surface 106 of one end 89a in the axial direction of the spool 89 is increased.
a and the side wall 103 are in contact with each other. In this state, a third valve hole 96 is arranged in each of the ports 91 and 92. In this way, the spool 89 can be slid in its axial direction by pilot pressure or spring force. Since the displacement of the spool 89 from the neutral position in the direction of the arrow E1 or E2 is performed by the pilot pressure, a driving force required for smoothly displacing the spool 89 can be easily obtained. Pilot room port 98
The throttles 99a, 99b are interposed between the pilot pressure chambers 100a, 100b and the pilot pressure chambers 100a, 100b.
Abrupt displacement from the neutral position 9 is suppressed. As a result, the disadvantage that the displacement speed of the spool 89 becomes excessively large, the first valve hole 94 is suddenly shut off, and the pressure in the pilot pressure passages 52 to 54 fluctuates greatly can be eliminated.

In the flow path resistance switching valve 55 and the valve body 88 of the present embodiment, three ports 91a, 91c and 91e on the direction switching valve side are provided on the lower surface 104b which is bent and connected to the front surface 104a of the valve body 88. Open. The lower surface 1
Each port 91a, 91c, 91e opening at 04b is
A lateral hole 107 extending on the same axis, and the lateral hole 107
Are connected to the ports 92a, 92c, 92e on the operation means side which are opened on the upper surface 104c of the valve main body 88 by the vertical holes 108 which are orthogonal to the axis of the valve body 107 and continuous with the horizontal holes 107.

The remaining ports 91b on the side of the direction switching valve,
Each of the ports 92d on the operating means side opens on the back surface 104d of the valve body 88 and opens on the upper surface 104c through a vertical hole 109 formed in the valve body 88.
b, 92d, and 92f.

Each of the connectors 105a and 105b of the electromagnetic solenoid unit 86 is disposed so as to extend in a direction perpendicular to the upper surface 104c. Therefore, in the present embodiment, the electric cords respectively connected to the first to third pilot pressure passages 52 to 54 on the operation means side connected to the respective ports 92 on the operation means side and the connectors 105a and 105b are complicated. It can be extended to the driver's seat of a construction machine without being arranged.

Referring to FIG. 3 again, the valve hole 96 of the one valve hole group 93 at the other end 89b in the axial direction of the spool 89 is formed as follows.
The other valve hole group 93 adjacent to the spool 89 in the axial direction is disposed at a distance L4 from the valve hole 94 near the one end 89a in the axial direction, but as another embodiment of the present invention, The third valve hole 96 of one valve hole group 93 and the first valve hole 94 of another valve hole group 93 adjacent to each other may intersect each other, that is, the distance L4 may be selected to be zero. . In this configuration, the valve hole groups 93 adjacent to each other are provided.
Are formed at a position shifted by a distance L2 in the circumferential direction of the spool 89 at an angle θ in the circumferential direction of the spool 89, so that the ports on the direction switching valve side or the ports on the operating means side are connected to each other. The disadvantage of mutual interference can be prevented, and the axial length of the spool 89 can be reduced as compared with the above-described embodiment.

In each of the embodiments described above, the spool valve in which the electromagnetic force and the pilot pressure are combined is used as the passage resistance switching valve 55, but the present invention is not limited to this.
For example, a flow path resistance switching lever may be connected to one end 89a in the axial direction or the other end 89b in the axial direction of the spool 89, and the operator may manually operate the spool 89. In each of the above embodiments, the hydraulic drive 4
Although a power shovel has been assumed as a target to which 1 is used, the present invention is not limited to this, and may be a construction machine such as a bulldozer and a crane, or a forest machine. Although the hydraulic drive device 41 is configured to include two hydraulic cylinders 42 and 43 and one hydraulic motor 44, the present invention is not limited thereto, and one or three or more hydraulic cylinders and two The above-described hydraulic motor may be provided.

The valve hole groups 93a to 93f are each composed of three valve holes 94 to 96, but are not limited thereto, and may be composed of two or more valve holes. The tank 56 and the tank 76 shown in FIG. 1 may be the same. Further, in the above-described embodiment, one passage resistance switching valve 55 is used for the first to third operation means 49 to 51, but the invention is not limited to this. May be provided with a flow path resistance switching valve respectively.
A configuration may be adopted in which a plurality of operation means are divided into a plurality of groups, and a flow path resistance switching valve is provided for each group. Although the valve holes 94 to 96 of the adjacent valve hole groups among the valve hole groups 93 a to 93 f are formed at positions shifted by forming an angle θ = 90 degrees, the angle θ exceeds zero and 90 °. It may be chosen to be less than degrees.

In the above embodiment, the “flow path resistance”
Means the difficulty of the flow caused by the throttle, but is not limited to this, and may be the difficulty of the flow caused by the pressure loss due to the complicated flow path shape.

[0062]

According to the first aspect of the present invention, a directional control valve for switching a supply direction of hydraulic oil supplied from a hydraulic source to an actuator, a supply direction of pilot pressure oil for switching the directional control valve, and A flow path resistance switching valve is interposed in the pilot pressure passage connecting the operation means for changing the supply amount. This flow path resistance switching valve has a plurality of flow paths having different flow path resistances, switches these flow paths in multiple stages according to an operator's intention, connects the flow paths to a pilot pressure passage, and a flow rate of pilot pressure oil, that is, The supply amount per unit time can be adjusted. For example, when the operator desires to reduce the response of the actuator control by the operation means, the pilot pressure passage is selected by selecting a passage having a passage resistance smaller than the passage resistance of the currently connected passage. If it is desired to improve the responsiveness, select a flow path having a flow resistance larger than the flow resistance of the currently connected flow path and connect the flow path to the pilot pressure path. do it. As described above, the operation characteristics of the control operation of the actuator can be changed in accordance with the preference of the operator. Therefore, in the configuration of the present invention, a change in the temporal environment such as summer and winter or day and night, and a change in the viscosity of the pilot pressure oil due to a difference in environmental temperature caused by a change in the geographical environment such as a flatland and a mountainous region. As a result, it is possible to prevent the operating characteristics of the hydraulic drive device from changing, and to operate the hydraulic drive device with a preferred operation feeling according to the individual differences and the skill level of the operator. In addition, since the operating characteristics can be changed,
Operability is improved.

According to the second aspect of the present invention, the first position of the spool provided in the flow path resistance switching valve is set at the predetermined position.
Are formed, and second and third valve holes are formed at both ends in the axial direction of the spool with respect to the first valve hole. Therefore, for example, when the operator feels uncomfortable with the operation feeling of the actuator in a state where the first valve hole is connected, the second or the second valve having a flow path resistance different from the flow path resistance of the first valve hole. The operation of switching to the valve hole 3 may be performed by switching the spool of the flow path resistance switching valve to one end or the other end in the axial direction of the spool by one step, and the displacement of the spool is as small as possible. And the responsiveness of the flow path resistance switching can be improved.

According to the third aspect of the present invention, the size of the flow path resistance switching valve can be reduced. That is, claim 2
As described in above, the one valve hole group is configured such that the first to third valve holes are arranged in a straight line along the axial direction of the spool. These first to third valve holes correspond to a pair of ports of an inlet port and an outlet port. Another valve hole group adjacent to this one valve hole group in the axial direction of the spool and corresponding to another pair of ports different from the pair of ports is:
Similarly to the one valve hole group, the first to third valve holes are arranged on a straight line along the axial direction of the spool, and each valve hole of the one valve hole group is shifted in the circumferential direction of the spool. It is arranged and configured.

[Brief description of the drawings]

FIG. 1 shows a hydraulic drive device 41 according to an embodiment of the present invention.
FIG.

FIG. 2 is a partial cross-sectional view illustrating a flow path resistance switching valve 55.

FIG. 3 is a perspective view showing a spool 89.

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 2;

FIG. 5 is a cross-sectional view taken along the line VV of FIG. 2;

FIG. 6 is a partial bottom view of the flow path resistance switching valve 55.

FIG. 7 is a plan view of a flow path resistance switching valve 55.

FIG. 8 is a hydraulic circuit diagram showing a hydraulic drive device 1 according to a first related art.

FIG. 9 is a hydraulic circuit diagram showing a hydraulic drive device 111 according to a second conventional technique.

FIG. 10 is a hydraulic circuit diagram of a hydraulic switching valve 121 used in a hydraulic drive device according to a third conventional technique.

[Explanation of symbols]

 41 Hydraulic drive device 42 First hydraulic cylinder 43 Second hydraulic cylinder 44 Hydraulic motor 45 Variable displacement pump 46 to 48 First to third direction switching valve 49 to 51 First to third operating means 52a, 52b First pilot pressure Passages 53a, 53b Second pilot pressure passages 54a, 54b Third pilot pressure passages 55 Flow resistance switching valves 81-83 Operating lever 86 Electromagnetic solenoid unit 88 Valve body 89 Spool 90 Operating unit 91a-91f Ports 92a-92f Ports 93a- 93f Valve hole group 94 First valve hole 95 Second valve hole 96 Third valve hole

Claims (3)

[Claims] 1. A hydraulic pressure source, an actuator driven by hydraulic pressure of hydraulic oil from the hydraulic pressure source, and a hydraulic pressure source interposed between the hydraulic pressure source and the actuator, for switching a supply direction of hydraulic oil from the hydraulic pressure source by pilot pressure. A directional control valve, operating means for changing the supply direction and supply amount of pilot pressure oil to the directional control valve by an operator's operation, and controlling the operation of the actuator; and a pilot for connecting the directional control valve to the operating means. And a flow path resistance switching valve interposed in the pressure passage and changing a flow rate of the pilot pressure oil by switching a plurality of flow paths having different flow path resistances in multiple stages. 2. The flow path resistance switching valve is formed at a first valve hole formed at a predetermined position and at one axial end side of the first valve hole. A second valve hole having a different flow path resistance, and a third valve hole formed at the other axial end of the first valve hole and having a different flow resistance from the first and second valve holes. 2. The hydraulic drive device according to claim 1, further comprising: a spool that is selectively switched between the first to third valve holes and communicates with the pilot pressure passage. 3. The spool according to claim 1, further comprising: one valve hole group including first to third valve holes; and another spool formed adjacent to the one valve hole group in the axial direction and displaced in the circumferential direction. The hydraulic drive device according to claim 2, further comprising a valve hole group.