KR101675659B1 - Pump control apparatus - Google Patents

Abstract

The pump control device includes an actuator for changing the discharge capacity of the pump and a regulator for regulating the control pressure guided by the actuator. The regulator includes a driving pressure port in which an average discharge pressure obtained by averaging discharge pressures of working fluids discharged from a plurality of discharge ports, an original pressure port in which the highest high-pressure discharge pressure is induced among working fluids discharged from a plurality of discharge ports, And a spool which adjusts the control pressure with the high pressure side discharge pressure as an original pressure by moving the valve by the average discharge pressure and the signal pressure, And a signal pressure water surface receiving the signal pressure is formed at the outer step portion of the spool.

Description

[0001] PUMP CONTROL APPARATUS [0002]

The present invention relates to a pump control apparatus for controlling a discharge capacity of a pump.

2. Description of the Related Art Conventionally, an inclined plate type multistage piston pump that is rotationally driven by an engine is used as a driving pressure source for a hydraulic device mounted on a working machine such as a hydraulic excavator. This piston pump has two sets of suction ports and discharge ports, and discharges the operating oil from each discharge port.

JP2008-291732A discloses a pump control apparatus for controlling the discharge capacity of an inclined plate type multistage piston pump. This pump control apparatus is provided with a regulator for controlling a tilting angle of the swash plate so as to make the uniformity of the piston pump constant, and an average discharge pressure obtained by averaging the discharge pressures derived from the respective discharge ports is used as an original pressure guided to the regulator .

JP2008-240518A discloses a regulator that controls the discharge capacity of a pump in accordance with a signal pressure induced when an apparatus such as an air conditioner operates in a piston pump driven by an engine.

However, in such a conventional pump control apparatus, there has been a problem that the spool constituting the regulator is increased in size as the number of signal pressures increases, or the structure of the regulator is complicated.

An object of the present invention is to provide a pump control apparatus for controlling the discharge capacity of a pump by using a regulator having a simple structure even if the number of signal pressures is increased.

According to one aspect of the present invention, there is provided a pump control apparatus for controlling a discharge capacity of a pump that discharges a working fluid from a plurality of discharge ports. The pump control device includes an actuator for changing the discharge capacity of the pump and a regulator for regulating the control pressure guided by the actuator. The regulator includes a driving pressure port in which an average discharge pressure obtained by averaging the discharge pressures of the working fluid discharged from the plurality of discharge ports and an original pressure port in which the highest discharge pressure of the highest pressure among the working fluids discharged from the plurality of discharge ports is induced A signal pressure port to which a signal pressure is induced, and a spool that adjusts the control pressure with an average discharge pressure and a signal pressure, and moves the high pressure side discharge pressure to an original pressure. In the spool, A water surface is formed, and a signal pressure water surface receiving the signal pressure is formed on the outer step portion of the spool.

1 is a hydraulic circuit diagram of a pump control apparatus according to an embodiment of the present invention.
2 is a cross-sectional view of a regulator according to an embodiment of the present invention.
3 is a characteristic diagram showing the relationship between the signal pressure and the discharge capacity of the pump control apparatus according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like.

1 is a hydraulic circuit diagram of a pump control apparatus 1 according to an embodiment of the present invention.

The pump control device 1 is a device for driving a hydraulic device mounted on a work machine such as a hydraulic excavator, for example, and controls the discharge displacement (pump displacement volume) of the variable displacement pump 11. [

The variable displacement pump 11 is, for example, an inclined plate type multistage piston pump, and has one suction port and two discharge ports.

The variable displacement pump 11 is driven by the engine 10 to suck hydraulic fluid from a suction port through a suction port 20 from a tank port 30 connected to a tank and to reciprocate following the swash plate 15 The operating oil pressurized by the piston is discharged from each of the discharge ports.

The operating oil discharged from each of the discharge ports flows through the boom, the arm and the bucket of the hydraulic excavator through the first discharge passage 21, the second discharge passage 22, the pump ports 31, 32 and the control valve And are distributed to respective hydraulic cylinders, left and right traveling motors, and the like.

A part of the operating fluid of the pressure P1 discharged from one of the discharge ports is supplied to the left traveling motor through the first discharge passage 21. [ A part of the operating oil of the pressure P2 discharged from the other discharge port is supplied to the traveling motor on the right side through the second discharge passage 22. [ And the flow rate of the hydraulic oil supplied to the left and right traveling motors is adjusted by the control valves for the left and right traveling motors, whereby the vehicle is stopped, straightly traveled, and turned.

The pump control apparatus 1 includes a first positive displacement pump 12 and a second positive displacement pump 13 disposed coaxially with the variable displacement pump 11. The first positive displacement pump 12 and the second positive displacement pump 13 are pumps having a constant discharge capacity and are driven by the variable displacement pump 11 and the common drive source engine 10. In the present embodiment, a gear pump is used as the first positive displacement pump 12 and the second positive displacement pump 13, but the invention is not limited thereto.

The first positive displacement pump 12 draws the working oil through the suction passage 25 branched from the suction passage 20 and sends the pressurized working oil to the pump port 39 through the third discharge passage 23 . The hydraulic oil is supplied to a swing motor or the like that swings a cap (driver's seat) of the hydraulic excavator by a control valve connected to the pump port 39. [

The second positive displacement pump 13 suctions the operating oil through the suction passage 26 branched from the suction passage 25 and sends the pressurized operating oil to the signal pressure port 34 through the signal pressure passage 24 . The hydraulic oil is supplied to a hydraulic drive unit or the like which switches each control valve through a signal pressure passage (not shown) connected to the signal pressure port 34.

In the present embodiment, although the operating oil (oil) is used as the operating fluid fed to the variable capacity pump 11, the first positive displacement pump 12 and the second positive displacement pump 13, A working fluid such as a substitute liquid may be used.

Next, a configuration for controlling the discharge capacity of the variable displacement pump 11 will be described.

The variable displacement pump 11, which is an inclined plate type piston type, includes a cylinder block that is rotationally driven by the engine 10, a piston that discharges hydraulic fluid sucked in and reciprocated in the cylinder of the cylinder block, The spring force control springs 48 and 49 press the swash plate 15 in the direction of increasing the tilting angle of the swash plate 15 and the swash plate 15 A large diameter actuator 16 for driving the swash plate 15 against the driving force of the small diameter actuator 47 and the spring force of the power control springs 48 and 49; And a casing for accommodating them.

The multivariable variable displacement pump 11 includes a cylinder having one intake port and two discharge ports and having a cylinder communicating with the first discharge passage 21 in the cylinder block and a cylinder communicating with the second discharge passage 22 And a cylinder.

The discharge capacity of the variable displacement pump 11 is changed by changing the tilting angle of the swash plate 15 by driving the large diameter actuator 16 and changing the piston stroke of the reciprocating piston following the swash plate 15, do.

The large-diameter actuator 16 reduces the tilting angle of the swash plate 15 as the control pressure Pcg induced to the actuator 16 increases. As the tilting angle of the swash plate 15 becomes smaller, the discharge capacity of the variable displacement pump 11 decreases.

The pump control apparatus 1 includes a load sensing regulator 60 (hereinafter referred to as an "LS regulator 60") that adjusts a control pressure Pcg induced by a large-diameter actuator 16, And a horsepower control regulator (40) that adjusts an induced hydraulic pressure (control pressure) Pc.

A throttling valve 57 is interposed in the second control-pressure passage 56. The throttling valve 57 relaxes the pressure fluctuation of the control pressure Pcg induced by the large-diameter actuator 16. The control pressure Pcg generated in the second control pressure passage 56 is taken out from the control pressure port 35 and detected by the pressure sensor.

The horsepower control regulator 40 is a three-port two-position changeover valve and has a spool 70 (see FIG. 2) for switching the position of the horsepower control regulator 40 to the position a or the position b.

The spring force of the horsepower control springs 48 and 49 is applied to the spool 70 and the discharge pressure P1 and the discharge pressure P2 of the operating oil discharged from each discharge port as the signal pressure (drive pressure) The average average discharge pressure Pave is derived through the discharge pressure signal passage 63. The spool 70 moves to a position where the average discharge pressure Pave and the spring force of the horsepower control springs 48 and 49 are balanced. Thereby, the position of the horsepower control regulator 40 is switched to the position a or the position b.

The discharge pressure signal passage 63 includes a first discharge pressure signal passage 61 and a second discharge pressure signal passage 62 branched from the first discharge passage 21 and the second discharge passage 22 . A throttling valve 64 is provided in the first discharge pressure signal passage 61. A throttling valve 65 is provided in the second discharge pressure signal passage 62.

A discharge pressure P1 generated in the first discharge passage 21 is guided through the throttling valve 64 and a discharge pressure P2 generated in the second discharge passage 22 is introduced into the discharge pressure signal passage 63, Is guided through the valve (65). Thereby, in the discharge pressure signal passage 63, an average discharge pressure Pave which averages the discharge pressure P1 and the discharge pressure P2 is generated. The average discharge pressure Pave is also taken out from the average discharge pressure port 32. [

One end of the horsepower control springs 48 and 49 is connected to the spool 70 and the other end is connected to the swash plate 15. [ The spring force of the horsepower control spring 49 is shorter than the spring length of the horsepower control spring 48 and the spring force of the horsepower control springs 48 and 49 is applied to the tilting angle of the swash plate 15 and the stroke of the spool 70 So that it is gradually increased.

The horsepower control regulator 40 generates an original pressure that is guided from the original pressure passage 53 to the first control pressure passage 55 and the original pressure from the first control pressure passage 55 to the low pressure passage 59, (Control pressure) Pc that is induced to the hydraulic oil pressure Pc.

The original pressure passage 53 has a first original pressure passage 51 and a second original pressure passage 52 branched from the first discharge passage 21 and the second discharge passage 22, And a high-pressure selector valve (50) for selectively causing the working fluid pressure (P1) generated in the first pressure passage (52) and the working fluid pressure (P2) generated in the second primary pressure passage (52) to be higher in the primary pressure passage (53).

Thereby, the operating oil pressure P1 that is guided from the first discharge passage 21 to the first original pressure passage 51 and the operating oil pressure P2 that is guided from the second discharge passage 22 to the second original pressure passage 52 are higher Pressure selection valve 50 and is guided to the horsepower control regulator 40 and the small-diameter actuator 47 through the original pressure passage 53. [

The horsepower control regulator (40) adjusts the operating oil pressure (Pc) so that the signal pressure based on the average discharge pressure (Pave) and the spring force of the horsepower control springs (48, 49) are balanced.

The horsepower control regulator 40 is connected to the signal pressure passage 29 branched from the third discharge passage 23 and connected to the first positive displacement pump 12 which is guided to the spool 70 by the signal pressure passage 29, (Hereinafter referred to as " second signal pressure ") P3 acts in a direction against the spring force. And the second signal pressure P3 is also taken out from the second signal pressure port 39. [

As the second signal pressure P3 rises, the spool 70 of the horsepower control regulator 40 switches to the position a when the load of the first positive displacement pump 12 that drives the swing motor becomes high, The operating hydraulic pressure Pc is increased.

An external signal pressure passage 28 is connected to the horsepower control regulator 40. The horsepower control signal pressure Pi induced by the external signal pressure passage 28 acts on the spool 70 in the same direction as the spring force do. Thus, when the horsepower control signal pressure Pi rises, the spool 70 of the horsepower control regulator 40 moves in the direction of switching to the position b, thereby lowering the operating hydraulic pressure Pc.

The LS regulator 60 is a three-port two-position switching valve and has a spool for switching the position of the LS regulator 60 to the position c or the position d.

At one end of the spool of the LS regulator 60, the signal pressure Pps generated on the upstream side of the control valve is led from the signal port 36 through the signal path 43.

The signal pressure Pls generated on the downstream side of the control valve is guided from the signal pressure port 37 through the signal path 44 to the other end of the spool of the LS regulator 60. [ A spring force of the LS spring 14 is applied to the other end of the spool of the LS regulator 60.

The spool of the LS regulator 60 moves to a position where the LS differential pressure Pps-Pls generated before and after the control valve and the spring force of the LS spring 14 acting on the other end are balanced. Thereby, the position of the LS regulator 60 is switched to the position c or the position d.

For example, when a load such as a boom, an arm, or each hydraulic cylinder driving the bucket is large, the signal pressure (load pressure) Pls that is guided from the downstream side (load side) of the control valve to the signal pressure port 37 rises . As a result, when the LS differential pressure Pps-Pls falls, the spool of the LS regulator 60 is held at the position c by the spring force of the LS spring 14 as shown in Fig. In this position c, the first control pressure passage 55 connected to the horsepower control regulator 40 is communicated with the second control pressure passage 56 connected to the large-diameter actuator 16, and the LS regulator 60, The control pressure Pcg induced to the large-diameter actuator 16 becomes a value based on the value Pc adjusted by the horsepower control regulator 40. [

On the other hand, when the loads of the hydraulic cylinders for driving the boom, the arm and the bucket are small, the signal pressure (load pressure) Pls is low. As a result, when the LS differential pressure Pps-Pls rises, the spool of the LS regulator 60 moves in the direction of switching to the position d against the spring force of the LS spring 14. [ In this position d, the primary pressure passage 54 branched from the secondary discharge passage 22 to induce the secondary pressure P2 is communicated with the second control pressure passage 56 connected to the large-diameter actuator 16, The pressure Pcg rises.

Thus, the LS regulator 60 adjusts the control pressure Pcg guided to the large-diameter actuator 16 so that the LS differential pressure and the spring force of the LS spring 14 are balanced. Thereby, the discharge capacity of the variable displacement pump 11 is controlled so that the LS differential pressure (Pps-Pls) becomes substantially constant even when the load of the hydraulic cylinder is increased or decreased.

The throttle valve 66 is provided in the first control pressure passage 55 and the throttling valve 67 is provided in the original pressure passage 54. This relieves pressure fluctuations of the source pressure induced in the LS regulator 60.

The control pressure passage (69) communicates with the first control pressure passage (55) and the second control pressure passage (56). A throttling valve 18 and a check valve 17 are provided in the control pressure passage passage 69.

The check valve 17 closes the valve when the control pressure Pcg of the second control pressure passage 56 is higher than the operating oil pressure Pc of the first control pressure passage 55 in the normal state. On the other hand, when the control pressure Pcg is lower than the operating oil pressure Pc by a predetermined value, the check valve 17 opens the valve and the operating oil pressure Pc of the first control pressure passage 55 bypasses the LS regulator 60 Diameter actuator (16) through the second control-pressure passage (56).

The pump control apparatus 1 is provided with an adjusting mechanism for increasing the discharge flow rate of the variable displacement pump 11 as the pump rotational speed of the second positive displacement pump 13 rises. This adjusting mechanism includes an throttle valve 27 which is interposed in the signal pressure passage 24 for guiding the operating oil discharged from the second positive displacement pump 13 and a throttle valve 27 which is connected to the LS regulator And a control pressure actuator 90 for driving a spool of the spool 60.

The upstream pressure P4 of the throttling valve 27 of the signal pressure passage 24 is guided to the control pressure actuator 90 through the upstream side control pressure communication passage 94 and the downstream pressure P5 of the throttling valve 27 Is guided through the downstream-side control pressure passage (95).

When the differential pressure P4-P5 of the throttle valve 27 increases as the pump rotation speed of the second positive displacement pump 13 rises, the piston of the control pressure actuator 90, which receives this differential pressure, (60) moves in the direction in which the opening degree of the position (c) increases. Thereby, the control pressure Pcg guided from the LS regulator 60 to the large-diameter actuator 16 decreases, and the discharge capacity of the variable displacement pump 11 is increased by the operation of the large-diameter actuator 16.

Next, a specific configuration of the horsepower control regulator 40 will be described.

2 is a cross-sectional view of a horsepower control regulator 40 according to an embodiment of the present invention.

2, the horsepower control regulator 40 includes a tubular housing 100 having a spool receiving hole 110, a cylindrical spool 110 slidably received in the spool receiving hole 110, (70). The housing (100) is installed in the casing of the variable displacement pump (11).

The spool (70) has a tip portion protruding from the opening end of the spool receiving hole (110), and a spring bearing is provided at the tip portion. The force control springs 48 and 49 (see FIG. 1) are interposed between the spring bearing and the feedback pin interlocked with the swash plate 15 of the variable displacement pump 11.

A plug 140 is screwed on the base end of the housing 100. The spool 70 is pressed in the direction toward the plug 140 (left direction in Fig. 2) by the horsepower control springs 48, 49, and its stroke is regulated by its base end contacting the plug 140. [

A back pressure chamber 130 is formed between the housing 100 and the proximal end of the spool 70 and the plug 140. The back pressure chamber 130 communicates with the inside of the casing (tank side) of the variable displacement pump 11 through the through hole.

The spool (70) is provided with a shaft hole (79) which opens at its base end and extends in the axial direction. In this shaft hole 79, a stepped cylindrical pin 96 is slidably received.

The pin 96 is restricted from moving in the leftward direction in Fig. 2 by its proximal end contacting the plug 140. The pin 96 includes a large diameter fin portion 98 that contacts the plug 140 and a small diameter fin portion 97 that is wider than the large diameter fin portion 98. The large diameter fin portion 98 and the small diameter fin portion 97 And a pin outer circumferential stepped portion 99 formed between the pin-shaped step portion 99 and the pin outer circumferential step portion 99.

The housing 100 has five ports 101 to 105. The ports 101 to 105 extend in the radial direction of the spool 70 and are opened in the spool receiving hole 110. [ The ports 101 to 105 communicate with the square cylinders 55, 53, 63, 29 and 28 (see Fig. 1) described above via respective annular grooves formed on the outer periphery of the spool 70.

The control pressure port 101 constitutes the first control pressure passage 55. An operating hydraulic pressure (control pressure) Pc induced to the large-diameter actuator 16 via the LS regulator 60 is generated in the control pressure port 101 by the operation of the spool 70. [

The original pressure port (102) constitutes the original pressure passage (53). The higher one of the discharge pressures P1 and P2 of the first discharge passage 21 and the second discharge passage 22 is guided to the original pressure port 102. [

And the drive pressure port 103 constitutes the discharge pressure signal passage 63. [ An average discharge pressure Pave obtained by averaging the discharge pressures P1 and P2 of the working fluid discharged from the respective discharge ports of the variable displacement pump 11 is induced in the drive pressure port 103. [

The second signal pressure port 104 constitutes the signal pressure passage 29. In the second signal pressure port 104, the pressure P3 of the hydraulic fluid supplied from the first constant-displacement pump 12 to the swing motor is induced.

The first signal pressure port 105 constitutes the external signal pressure passage 28. The first signal pressure port 105 is supplied with a horsepower control signal pressure Pi for switching the operation mode.

The tank pressure port communication hole 71, the driving pressure port communication hole 72 and the second signal pressure port communication hole 73 are formed in the spool 70. The port communicating holes 71 to 73 extend in the radial direction of the spool 70 and both ends thereof are open in an annular groove formed on the outer periphery of the spool 70.

At the tip of the spool 70, a tank pressure port 74 is formed. The tank pressure port 74 extends in the axial direction of the spool 70 and has one end opened in the tank pressure port communicating hole 71 and the other end opened in the tip of the spool 70, And communicates with the inside of the casing (tank side) of the pump 11. The tank pressure port 74 discharges the working oil pressure Pc into the casing.

Six land portions 81 to 86 annularly protruding are formed on the outer periphery of the spool 70. Each of the land portions 81 to 86 is in sliding contact with the inner periphery of the spool receiving hole 110.

The spool 70 is moved in the axial direction to be switched to the position a and the position b so that the land portions 81 and 82 are engaged with the tank pressure port communicating hole 71 and the original pressure port 102 with respect to the spool receiving hole 110 And the working oil pressure (control pressure) Pc generated in the control pressure port 101 is adjusted.

The land portion 81 cuts off between the tank pressure port communicating hole 71 and the control pressure port 101 while the spool 70 is between the position a and the position b and the land portion 82 Blocking between the original pressure port 102 and the control pressure port 101 is blocked.

2, the tank pressure port communicating hole 71 and the control pressure port 101 communicate with each other, and the operating oil pressure Pc is discharged into the case and is lowered. At this time, the land portion 82 blocks the gap between the original pressure port 102 and the control pressure port 101.

When the spool 70 is moved to the right in Fig. 2 and is switched to the position a, the source pressure port 102 and the control pressure port 101 communicate with each other and the discharge pressure P1 or P2 The higher pressure is guided to the LS regulator 60 through the first control pressure passage 55, and the operating oil pressure Pc rises. At this time, the land portion 81 cuts off the space between the tank pressure port communication hole 71 and the control pressure port 101.

The drive pressure port communication hole 72 and the drive pressure port 103 are always communicated with each other regardless of the position of the spool 70. The land portion 83 cuts off the communication between the driving pressure port 103 and the original pressure port 102 and the land portion 84 is moved between the driving pressure port 103 and the second signal pressure port 104 .

The distal end 95A of the pin 96 protruding from the opening end of the shaft hole 79 faces the middle of the driving pressure port communication hole 72. [ A portion opposed to the tip end 95A of the pin 96 on the inner wall surface of the driving pressure port communicating hole 72 constitutes the driving pressure water surface 72A. The driving pressure water surface 72A has a water surface area corresponding to the cross sectional area of the small diameter fin portion 97. [ The spool 70 is moved in the rightward direction in Fig. 2 by the average discharge pressure Pave received on the driving pressure water surface 72A and the front end portion of the spool 70 is pushed out from the housing 100. Fig.

A recess 89 is formed in a portion of the inner wall surface of the driving pressure port communicating hole 72 opposed to the end 95A of the pin 96. The concave portion 89 is formed coaxially with the shaft hole 79 so that the tip 95A of the pin 96 does not interfere with the spool 70. [

A second signal pressure chamber 121 is defined between the shaft hole 79 and the pin 96. The second signal pressure chamber 121 and the second signal pressure port communication hole 73 and the second signal pressure port 104 are always communicated with each other regardless of the position of the spool 70. The land portion 85 blocks the communication between the second signal pressure port 104 and the first signal pressure port 105. [

The pin outer peripheral stepped portion 99 of the pin 96 faces the second signal pressure chamber 121 and the pin outer peripheral stepped portion 99 of the pin 96 on the inner wall surface of the second signal pressure port communicating hole 73 ) Constitute the second signal pressure water surface 73A. The second signal pressure water surface 73A has a water surface area equivalent to the sectional area difference between the small diameter fin 97 and the large diameter fin 98. [ The spool 70 is moved to the right in Fig. 2 by the second signal pressure P3 received on the second signal pressure surface 73A, and the tip of the spool 70 is pushed out of the housing 100. [

The spool 70 has a small-diameter spool portion 77, a large-diameter spool portion 76 that is thicker than the small-diameter spool portion 77, and an outer peripheral step portion 78 formed at a middle portion thereof.

The spool receiving hole 110 of the housing 100 has a small diameter hole portion 111 into which the small diameter spool portion 77 is inserted and a large diameter hole portion 112 into which the large diameter spool portion 76 is inserted .

A first signal pressure chamber 120 is defined between the large-diameter hole portion 112 of the housing 100 and the spool 70. The first signal pressure chamber 120 and the first signal pressure port 105 are always communicated with each other regardless of the position of the spool 70. The land portion 86 interrupts the communication between the first signal pressure chamber 120 and the back pressure chamber 130.

The outer peripheral stepped portion 78 of the spool 70 faces the first signal pressure chamber 120 and a portion corresponding to the cross sectional area difference between the small diameter spool portion 77 and the large diameter spool portion 76 is the first signal pressure And constitute the water surface 78A. The spool 70 is moved to the left in Fig. 2 by the horsepower control signal pressure Pi received on the first signal pressure water surface 78A.

Next, the operation of the horsepower control regulator 40 will be described.

2, when the force due to the average discharge pressure Pave received by the drive-pressure water surface 72A of the spool 70 is smaller than the spring force of the horsepower control springs 48 and 49, the horsepower control regulator 40 The spool 70 is moved to the position b. In the position b, the working oil pressure Pc is discharged from the control pressure port 101 to the tank pressure port 74 and falls.

On the other hand, when the force by the average discharge pressure Pave received on the driving pressure water surface 72A of the spool 70 is larger than the spring force of the horsepower control springs 48 and 49, And the horsepower control regulator 40 is switched to the position of the position a. In the position a, the hydraulic pressure higher than the operating hydraulic pressures P1 and P2 is induced from the original pressure port 102 to the control pressure port 101, and the operating hydraulic pressure Pc of the control pressure port 101 rises.

Thus, the horsepower control regulator 40 adjusts the operating oil pressure Pc so that the signal pressure based on the average discharge pressure Pave and the spring force of the horsepower control springs 48, 49 are balanced. The control pressure Pcg induced through the LS regulator 60 is increased by the operation of the horsepower control regulator 40 when the average discharge pressure Pave becomes high even if the rotational speed of the variable displacement pump 11 becomes high, The discharge capacity of the pump 11 decreases.

The control system of the hydraulic excavator includes a high load mode (normal operation mode) in which the engine 10 is operated at a predetermined rated rotational speed and a low load mode in which the engine 10 is operated at a rotational speed lower than the rated rotational speed Mode). The horsepower control signal pressure Pi is boosted in the high load mode while it is switched low in the low load mode. This mode is switched by a switch operation of the driver or the like, but the present invention is not limited to this, and the mode may be automatically performed in accordance with the operation or stop of the air conditioner (air conditioner).

In the operation in which the mode is switched from the high load mode to the low load mode, the horsepower control regulator 40 calculates the horsepower control signal Pi by the horsepower control signal pressure Pi received on the first signal pressure water surface 78A as the horsepower control signal pressure Pi is switched low The spool 70 moves in the direction in which the horsepower control regulator 40 is switched to the position of the position a. As a result, the operating oil pressure Pc of the control pressure port 101 is increased and the discharge capacity of the variable displacement pump 11 is reduced.

Further, during the operation in which the swing motor turns the cap, the operating hydraulic pressure P3 supplied from the first positive displacement pump 12 to the swing motor rises. At this time, in the horsepower control regulator 40, the second signal pressure P3 received by the second signal pressure surface 73A rises, and the spool 70 is moved in the direction in which the horsepower control regulator 40 is switched to the position of the position a. . As a result, the working oil pressure Pc of the control pressure port 101 is increased, and the discharge capacity of the variable displacement pump 11 is reduced.

Fig. 3 is a characteristic diagram showing the relationship between the signal pressures Pave, Pi, P3 and the discharge capacity of the variable displacement pump 11. Fig.

The discharge capacity of the variable displacement pump 11 decreases as the average discharge pressure Pave increases due to the operation of the horsepower control regulator 40. [ Thereby, the uniformity (horsepower) of the variable displacement pump 11 is adjusted so as to become substantially constant, and the operation is smoothly performed even when the number of revolutions of the engine 10 is increased or decreased. In the low load mode, the discharge capacity of the variable displacement pump 11 is reduced in comparison with the high load mode by the operation of the horsepower control regulator 40 by the horsepower control signal pressure Pi. As a result, the uniformity of the variable displacement pump 11 is lowered, and the load applied to the engine 10 driving the variable displacement pump 11 is reduced. The discharge capacity of the variable displacement pump 11 is reduced by the operation of the horsepower control regulator 40 by the second signal pressure P3 from the first constant displacement pump 12 during the operation of the swing motor. As a result, the uniformity of the variable displacement pump 11 is lowered, and the load applied to the engine 10 driving the variable displacement pump 11 is reduced.

According to the embodiment described above, the following operational effects are exhibited.

[1] The horsepower control regulator 40 includes a driving pressure port 103 for guiding an average discharge pressure Pave obtained by averaging discharge pressures P1 and P2 of working fluid discharged from a plurality of discharge ports, and an operation The signal pressure port 105 in which the hysteresis control signal pressure Pi is induced, the average discharge pressure Pave and the horsepower control signal pressure Pi are received And a spool 70 that regulates the control pressure Pc with the high-pressure discharge pressures P1 and P2 as primary pressures. A drive-pressure water surface 72A for receiving the average discharge pressure Pave is formed in the spool 70, The signal pressure water surface 78A receiving the horsepower control signal pressure Pi is formed on the outer step portion 78 of the piston 70. [

The spool 70 of the horsepower control regulator 40 calculates the average discharge pressure Pave obtained by averaging the discharge pressures P1 and P2 of the working fluid discharged from the plurality of discharge ports of the variable displacement pump 11, And the control pressure Pc guided to the large-diameter actuator 16 is set to be the highest pressure, which is the highest one of the discharge pressures P1 and P2 among the discharge pressures of the working fluid discharged from the plurality of discharge ports, . The spool 70 also regulates the control pressure Pc by moving the horsepower control signal pressure Pi to the signal pressure water surface 78A of the outer step portion 78. [ The pump control device 1 thus has a structure in which the driving pressure water surface 72A is provided inside the spool 70 so that the power control regulator 40 of a simple structure can be used without causing the spool 70 to be large- It is possible to control the uniformity of the variable displacement pump 11 according to the discharge pressures P1 and P2 and the horsepower control signal pressure Pi of the variable displacement pump 11. [

In addition, as a comparative example, it is considered to use a regulator in which a plurality of outer step portions are formed on the spool, and a driving pressure water surface for respectively receiving the discharge pressures P1 and P2 at the outer peripheral step portions is used. As another comparative example, it is considered to use a regulator provided with a plurality of pin members interlocking with the spool, and a drive-pressure water surface for receiving the discharge pressures P1 and P2 on the respective pin members. In these comparative examples, since the spool 70 is provided with the driving pressure water surface 72A which receives the average discharge pressure Pave obtained by averaging the discharge pressures P1 and P2 inside thereof, a plurality of There is no need to form an outer step portion, and the enlargement can be suppressed. Further, the horsepower control regulator 40 does not need to have a plurality of pin members interlocked with the spool 70, and a simple structure can be realized.

[2] The horsepower control regulator 40 includes a driving pressure port communicating hole 72 communicating with the driving pressure port 103 formed inside the spool 70, a driving pressure port communicating hole 72 formed inside the spool 70, A shaft hole 79 connected to the port communicating hole 72 and a pin 96 slidably inserted into the shaft hole 79 are formed in the inner wall surface of the driving pressure port communicating hole 72, And the portion opposed to the driving-force water surface 96 constitutes the driving-pressure water surface 72A.

Thus, since the pin 96 is received in the spool 70 and the drive-pressure water surface 72A is provided so as to face the pin 96, by providing the drive-pressure water surface 72A, the horsepower control regulator 40 are prevented from becoming larger in the axial direction of the spool 70.

[3] The horsepower control regulator 40 includes a second signal pressure port 104 through which a second signal pressure P3 different from the horsepower control signal pressure Pi is induced, a second signal pressure port 104 formed inside the spool 70, And a second signal pressure port communication hole (73) communicating with the second signal pressure port (104), wherein the pin (96) has a pin outer peripheral stepped portion (99) A portion of the inner wall surface of the pressure port communicating hole 73 opposed to the pin outer peripheral stepped portion 99 constitutes the second signal pressure surface 73A receiving the second signal pressure P3.

Thus, since the second signal pressure surface 73A receiving the second signal pressure P3 is provided opposite to the pin outer circumferential step 99 of the pin 96, by providing the second signal pressure surface 73A, The control regulator 40 is restrained from becoming larger in the axial direction of the spool 70.

(4) The pump control apparatus 1 is configured such that when the load of the engine 10 that drives the variable displacement pump 11 is high and the load is in the high load mode, Pi is increased to move the spool 70 in the direction in which the discharge capacity of the variable displacement pump 11 is increased and when the load of the engine 10 is low in the low load mode, 78 to lower the horsepower control signal pressure Pi to move the spool 70 in a direction in which the displacement capacity of the variable displacement pump 11 decreases.

As a result, the spool 70 is moved by the lowering of the horsepower control signal pressure Pi and the discharge capacity of the variable displacement pump 11 is reduced as the mode is switched from the high load mode to the low load mode. The horsepower control signal pressure Pi is lowered in the low load mode, so that the driving load of the first positive displacement pump 12 is reduced and the energy consumption of the pump control apparatus 1 is reduced.

Although the embodiments of the present invention have been described above, the above embodiments are only illustrative of some of the application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments.

For example, the pump control device 1 is not limited to a working machine such as a hydraulic excavator, but can be used also as a fluid pressure supply source provided in other machines and equipment.

The present application claims priority based on Japanese Patent Application No. 2013-66851 filed on March 27, 2013, filed with the Japanese Patent Office, the entire contents of which are incorporated herein by reference.

Claims (5)

A pump control apparatus for controlling a discharge capacity of a pump for discharging a working fluid from a plurality of discharge ports,
An actuator for changing the discharge capacity of the pump,
And a regulator for regulating the control pressure induced by the actuator,
The regulator includes:
A driving pressure port in which an average discharge pressure obtained by averaging discharge pressures of working fluids discharged from a plurality of discharge ports,
Pressure discharge port in which the highest-pressure side discharge pressure of the working fluid discharged from the plurality of discharge ports is induced,
A signal pressure port in which a signal pressure is induced,
And a spool which receives the average discharge pressure and the signal pressure and adjusts the control pressure by using the high-pressure discharge pressure as an original pressure,
A driving pressure water surface receiving the average discharge pressure is formed inside the spool,
A signal pressure water surface receiving the signal pressure is formed on the outer step portion of the spool,
The regulator includes:
A driving pressure port communicating hole formed in the spool and communicating with the driving pressure port,
A shaft hole formed in the spool and connected to the driving pressure port communication hole,
Further comprising a pin slidably inserted into the shaft hole,
A portion opposed to the pin on the inner wall surface of the driving-pressure-port communication hole constitutes the driving-pressure water surface,
Wherein the drive-pressure water surface is formed as a concave portion for accommodating a tip end of the pin. delete The fuel cell system according to claim 1, wherein the regulator includes:
A second signal pressure port through which a second signal pressure different from the signal pressure is induced,
And a second signal pressure port communication hole formed in the spool and communicating with the shaft hole and the second signal pressure port,
Wherein the pin has a pin outer peripheral stepped portion at an intermediate position thereof,
And a portion of the inner wall surface of the second signal pressure port communication hole facing the pin outer peripheral step portion constitutes a second signal pressure surface receiving the second signal pressure. The pump control apparatus according to claim 1,
The signal pressure of the outer peripheral step of the spool is increased to move the spool in a direction in which the discharge capacity of the pump is increased when the load in the drive source driving the pump is high,
Wherein when the load of the drive source is low, the signal pressure of the outer step of the spool is lowered to move the spool in a direction in which the discharge capacity of the pump is reduced. A pump control apparatus for controlling a discharge capacity of a pump for discharging a working fluid from a plurality of discharge ports,
An actuator for changing the discharge capacity of the pump,
And a regulator for regulating the control pressure induced by the actuator,
The regulator includes:
A driving pressure port in which an average discharge pressure obtained by averaging discharge pressures of working fluids discharged from a plurality of discharge ports,
Pressure discharge port in which the highest-pressure side discharge pressure of the working fluid discharged from the plurality of discharge ports is induced,
A signal pressure port in which a signal pressure is induced,
And a spool which receives the average discharge pressure and the signal pressure and adjusts the control pressure by using the high-pressure discharge pressure as an original pressure,
A driving pressure water surface receiving the average discharge pressure is formed inside the spool,
A signal pressure water surface receiving the signal pressure is formed on the outer step portion of the spool,
The regulator includes:
A second signal pressure port through which a second signal pressure different from the signal pressure is induced,
And a second signal pressure port communication hole formed in the spool and communicating with the shaft hole and the second signal pressure port,
Wherein the pin has a pin outer peripheral stepped portion at an intermediate position thereof,
And a portion of the inner wall surface of the second signal pressure port communication hole facing the pin outer peripheral step portion constitutes a second signal pressure surface receiving the second signal pressure.

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