JP2012107664A - Hydraulic drive device, and working machine equipped with hydraulic drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic drive device capable of suppressing hunting of a hydraulic actuator which occurs by a rapid operation input by an operator.SOLUTION: The hydraulic drive device includes: a variable displacement hydraulic pump P; and a pump control unit 150 that controls a discharge oil amount of the hydraulic pump P by changing the capacity of the hydraulic pump P. The pump control unit 150 includes: a capacity cylinder 151 that changes the variable capacity of the hydraulic pump P by using a capacity control hydraulic pressure; and a regulator valve R that produces the capacity control hydraulic pressure by using a load hydraulic pressure acting on the hydraulic actuator. The regulator valve R includes a hydraulic pressure fluctuation suppressing unit that suppresses influences of fluctuation in the load hydraulic pressure when the load hydraulic pressure varies, and produces the capacity control hydraulic pressure.

Description

  The present invention relates to a hydraulic drive device mounted on a work machine configured to perform a required work by a construction work device driven by a hydraulic actuator.

  As a working machine as described above, for example, on a traveling body configured to run freely, a swivel base that is swiveled by a hydraulic motor is provided, and pressure supplied to the swivel base by an engine or an electric motor-driven hydraulic pump is provided. 2. Description of the Related Art Power shovels and the like provided with a working device including a boom, an arm, a bucket and the like driven by a hydraulic actuator using oil are widely known. As described above, some of the working machines that use the pressure oil discharged from the hydraulic pump include a hydraulic drive device having a load sensing function that varies the discharge hydraulic pressure of the hydraulic pump according to the load hydraulic pressure of the hydraulic actuator. Are known (for example, see Patent Document 1).

JP-A-9-287173

  In the hydraulic drive device having the load sensing function as described above, when the load hydraulic pressure of the hydraulic actuator fluctuates suddenly due to the rapid actuator operation input by the operator, the discharge hydraulic pressure of the hydraulic pump is also controlled rapidly. There is a problem that actuator hunting occurs. In addition, when hunting occurs in this way, the work machine vibrates and the worker is swung, so that there is another problem that hunting of the hydraulic actuator is further increased.

  The present invention has been made in view of such a problem, and a hydraulic drive device capable of suppressing hunting of a hydraulic actuator generated by an operator's rapid operation input, and a work machine including the hydraulic drive device The purpose is to provide.

  In order to achieve the above object, a hydraulic drive device according to the present invention includes a variable displacement hydraulic pump, a hydraulic actuator driven by pressure oil discharged from the hydraulic pump, and a displacement of the hydraulic pump. Pump control means for controlling the amount of oil discharged from the hydraulic pump, and the pump control means uses a capacity control oil pressure to change the variable capacity of the hydraulic pump (for example, the capacity in the embodiment). Cylinder 151) and capacity control pressure adjusting means (for example, regulator valves R, R ′, R ″ in the embodiment) for generating the capacity control oil pressure using a load oil pressure acting on the hydraulic actuator, and the capacity control The hydraulic pressure varies the variable capacity of the hydraulic pump so that the discharge hydraulic pressure of the hydraulic pump is higher than the load hydraulic pressure by a predetermined pressure. The capacity control pressure adjusting means is configured to include a hydraulic pressure fluctuation suppressing means for generating the capacity control hydraulic pressure by suppressing the influence of the load hydraulic pressure fluctuation when the load hydraulic pressure fluctuates. .

  The hydraulic drive apparatus having the above-described configuration includes a hydraulic pressure supply control unit that controls the hydraulic pressure supplied from the hydraulic pump to the hydraulic actuator using a pilot hydraulic pressure that is supplied in accordance with an actuator operation input by an operator. The hydraulic pressure fluctuation suppression means suppresses fluctuations in the load hydraulic pressure supplied to the capacity control pressure regulating means to produce the capacity control hydraulic pressure using fluctuations generated in the pilot hydraulic pressure in response to the actuator operation input. The displacement control hydraulic pressure is generated using the load hydraulic pressure whose fluctuation is suppressed.

  Further, in the hydraulic drive apparatus having the above-described configuration, the hydraulic pressure fluctuation suppression unit includes a load hydraulic pressure detection unit that detects the load hydraulic pressure (for example, the pressure sensor 205 in the embodiment), and the load detected by the load hydraulic pressure detection unit. Fluctuation suppression pressure adjusting means (for example, the load pressure control unit 210 and the pressure reducing valve 220 in the embodiment) that generates a fluctuation suppression hydraulic pressure with a fluctuation rate lower than the fluctuation rate of the load hydraulic pressure based on a detection signal corresponding to the hydraulic pressure. And the displacement control hydraulic pressure generated by the fluctuation suppression pressure adjusting means is used to generate the displacement control hydraulic pressure.

  Further, in the hydraulic drive device having the above-described configuration, the hydraulic pressure fluctuation suppression unit includes an accumulator (for example, an implementation) provided in an oil path of the load hydraulic pressure supplied to the capacity control pressure adjusting unit to generate the capacity control hydraulic pressure. An accumulator 310) in the form, and configured to produce the displacement control oil pressure using the load oil pressure whose fluctuation is suppressed by the accumulator.

  In order to achieve the above object, a work machine according to a second aspect of the present invention includes the hydraulic drive device configured as described above and a construction work device driven by the hydraulic actuator, The work device is configured to perform a required work.

  According to the hydraulic drive device of the present invention, when the load hydraulic pressure fluctuates, the capacity control pressure adjusting means for generating the capacity control hydraulic pressure for changing the variable capacity of the hydraulic pump using the load hydraulic pressure acting on the hydraulic actuator. In addition, since it is configured with hydraulic fluctuation suppression means that suppresses the influence of fluctuations in the load hydraulic pressure and generates capacity control hydraulic pressure, when the load hydraulic pressure of the hydraulic actuator fluctuates suddenly, Can be suppressed from fluctuating rapidly. Therefore, the hydraulic actuator can be driven smoothly without abruptly changing the amount of oil discharged from the hydraulic pump, and hunting of the hydraulic actuator can be suppressed.

  In the above hydraulic drive device, the hydraulic pressure fluctuation suppression means is supplied to the capacity control pressure adjusting means in order to create a capacity control hydraulic pressure by using the fluctuation generated in the pilot hydraulic pressure of the hydraulic pressure supply control means according to the actuator operation input. It is preferable to be configured to suppress the fluctuation of the load hydraulic pressure and generate the capacity control hydraulic pressure using the load hydraulic pressure in which the fluctuation is suppressed. When the operator inputs the actuator operation input, the pilot hydraulic pressure and the load hydraulic pressure fluctuate synchronously according to the operation input. Therefore, the fluctuation of the load hydraulic pressure can be suppressed using the fluctuation of the pilot hydraulic pressure. it can. Therefore, when the load hydraulic pressure changes rapidly due to the operator's rapid operation input, it is possible to suppress the capacity control hydraulic pressure from changing rapidly according to the change. Therefore, the hydraulic actuator can be driven smoothly without abruptly changing the amount of oil discharged from the hydraulic pump, and hunting of the hydraulic actuator can be suppressed.

  Further, in the hydraulic drive apparatus, the hydraulic pressure fluctuation suppression means is a fluctuation that generates a fluctuation suppression hydraulic pressure having a fluctuation rate lower than the fluctuation rate of the load hydraulic pressure based on a detection signal corresponding to the load hydraulic pressure detected by the load hydraulic pressure detection means. It is preferable that a suppression pressure adjusting unit is provided, and the displacement control hydraulic pressure generated by the fluctuation suppression pressure control unit is used to generate a displacement control hydraulic pressure. With this configuration, since the capacity control hydraulic pressure is generated using the fluctuation suppression hydraulic pressure having a fluctuation rate lower than the load hydraulic pressure fluctuation rate, when the load hydraulic pressure changes rapidly, the capacity control hydraulic pressure is changed according to the change. Rapid fluctuation can be suppressed. Therefore, the hydraulic actuator can be driven smoothly without abruptly changing the amount of oil discharged from the hydraulic pump, and hunting of the hydraulic actuator can be suppressed.

  Further, in the above hydraulic drive device, the hydraulic pressure fluctuation suppressing means includes an accumulator provided in an oil passage of a load hydraulic pressure supplied to the capacity control pressure adjusting means in order to generate the capacity control hydraulic pressure, and the fluctuation is suppressed by the accumulator. It is preferable that the load control hydraulic pressure is used to generate the capacity control hydraulic pressure. With this configuration, when the load hydraulic pressure fluctuates rapidly, the load hydraulic pressure fluctuation can be absorbed by the accumulator, so that the capacity control hydraulic pressure fluctuates rapidly according to the load hydraulic pressure fluctuation. Can be suppressed. Therefore, the hydraulic actuator can be driven smoothly without abruptly changing the amount of oil discharged from the hydraulic pump, and hunting of the hydraulic actuator can be suppressed.

  According to the work machine concerning the 2nd present invention, since it is provided with the above-mentioned hydraulic drive unit, hunting of a hydraulic actuator can be controlled as mentioned above.

1 is a hydraulic circuit diagram showing a first embodiment of a hydraulic drive device according to the present invention. 1 is an external perspective view of a power shovel shown as an example of a work machine provided with a hydraulic drive device according to the present invention. It is a block diagram of the drive control system in the said power shovel. It is a hydraulic circuit diagram which shows 2nd Embodiment of the hydraulic drive device which concerns on this invention. FIG. 5 is a hydraulic circuit diagram showing a third embodiment of a hydraulic drive device according to the present invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. As an example of a work machine equipped with a hydraulic drive device according to the present invention, an external perspective view of a power shovel PS is shown in FIG. 2, and a block diagram of a drive control system in this power shovel PS is shown in FIG. A schematic configuration of the power shovel PS will be described with reference to these drawings.

  The power shovel PS is configured to include a traveling device 1 configured to be able to travel, a swivel base 2 provided on the traveling device 1 so as to be capable of horizontal swiveling, and a work device 3 attached to the swivel base 2. .

  The traveling device 1 is configured by providing a crawler mechanism 10 including a driving wheel 11, a driven wheel 12, and a crawler belt 13 that is hung around these wheels and installed on the ground on the left and right sides of the body frame 15. The left and right crawler mechanisms 10 and 10 are respectively provided with a left traveling motor 81a and a right traveling motor 81b that rotationally drive the drive wheels 11 and 11, respectively, and the rotation (rotational direction and rotational speed) of the left and right traveling motors 81a and 81b. ) Is controlled so that it can travel in any direction.

  The main body frame 20 of the swivel base 2 is attached to the center upper portion of the vehicle body frame 15 via a turning drive mechanism (not shown) so as to be horizontally turnable, and a turning motor 86 provided in the turning drive mechanism is rotated forward or backward. Thus, the swivel base 2 can be turned horizontally with respect to the traveling device 1 in a right turn (clockwise in a plan view) or a left turn (counterclockwise in a plan view). A work device bracket 21 is formed on the main body frame 20 so as to protrude forward, and a shovel device 30 is attached as the work device 3 here.

  The excavator device 30 is pivotally connected to the work device bracket 21 so as to be swingable up and down, and is pivotally connected to the boom 33 provided to be able to move up and down by the expansion and contraction operation of the boom cylinder 83 and to the tip end portion of the boom 33. The arm 34 is provided so as to be able to bend and extend by the expansion and contraction operation of the arm cylinder 84, and the bucket is pivotally connected to the tip end portion of the arm 34 so as to be swingable up and down, and is provided so as to be swingable by the expansion and contraction operation of the bucket cylinder 85 35.

  On the main body frame 20 of the swivel base 2, an operator cabin 25 on which an operator gets on is provided. Inside the operator cabin 25 are an operator seat 26 on which an operator sits, a pair of left and right traveling operation levers 27a and 27b for operating the traveling device 1, the swivel base 2 and the working device 3 (excavator device 30). Left and right work operation levers 28a and 28b that perform operation operations, and a controller 40 that controls the operation of each unit based on operations on the operation levers are provided. Further, in the vehicle body cover 22 at the rear of the operator cabin, a power unit 4 (see FIG. 1) composed of an engine or an electric motor and a hydraulic drive unit composed of a hydraulic pump driven by the power unit 4 are provided. Yes.

  The travel operation levers 27a, 27b and the work operation levers 28a, 28b are provided with operation detectors 27as, 27bs, 28as, 28bs for detecting the position state of each operation lever (inclination operation direction and operation amount from the neutral position), respectively. The operation signal detected by each operation detector is input to the controller 40. The operation detector may be configured to detect the position state of each operation lever. For example, when a hydraulic control valve is used as the operation device, a pilot that varies depending on one state of the operation lever. When an electric joystick is used as the operating device, it is configured using a potentiometer that detects an electric resistance that varies depending on the position state of the operating lever.

  The controller 40 generates a command signal based on the operation signals input from the operation detectors of the travel operation levers 27a and 27b and the work operation levers 28a and 28b, and outputs the command signal to a hydraulic drive device described later. The operation of each part such as the traveling device 1, the swivel base 2, and the work device 3 is controlled.

  In the power shovel PS configured as described above, the left and right traveling operation levers 27a and 27b are tilted forward and backward from the neutral position to output a command signal from the controller 40 to the hydraulic drive device. Based on the control, the hydraulic oil supply device controls the supply amount and supply direction of the pressure oil supplied to the left and right traveling motors 81a and 81b, and can move the vehicle in an arbitrary direction. Further, by tilting the left and right work operation levers 28a, 28b forward, backward, left, and right from the neutral position, the hydraulic drive device can rotate the turning motor 86 and the work device 3 based on a command signal from the controller 40. The excavator device 30 can excavate the ground and the like by controlling the supply amount and supply direction of the pressure oil supplied to each of the cylinders 83, 84, 85. Hereinafter, a hydraulic drive device for a power shovel will be described.

  As shown in FIGS. 1 and 3, the hydraulic drive device 100 includes a hydraulic pump P capable of changing the capacity by changing the inclination of the swash plate S, and the pressure oil supplied from the hydraulic pump P to each hydraulic actuator. The control valve group 60 that performs supply control and a command signal output from the control controller 40 by the tilting operation of the operation lever are driven to drive, and the operating hydraulic pressure supplied from the hydraulic source is output to the control valve group 60 as a pilot pressure. The remote control valve group 50 and pump control means 150 for controlling the amount of oil discharged from the hydraulic pump P by changing the variable capacity of the hydraulic pump P are configured.

  The remote control valve group 50 includes a left traveling remote control valve 51a driven by a tilting operation of the left traveling operation lever 27a, a right traveling remote control valve 51b driven by a tilting operation of the right traveling operation lever 27b, and left and right work operation levers 28a. , 28b, the boom remote control valve 53, the arm remote control valve 54, the bucket remote control valve 55, and the swing remote control valve 56 that are driven by the tilting operation, and the pilot pressure corresponding to the operation direction and the operation amount of each operation lever. Is output to each control valve of the control valve group 60 via the pilot oil passage. In FIG. 1, the boom remote control valve 53, the arm remote control valve 54, the bucket remote control valve 55, and the turning remote control valve 56 are not shown, and only the left and right traveling remote control valves 51a and 51b are shown.

  A first communicating pilot oil passage 91 is provided between the left running pilot oil passages 57, 57 ′ of the left running remote control valve 51 a, and a first shuttle valve 101 is provided in the first communicating pilot oil passage 91. A second communicating pilot oil passage 92 is provided between the right running pilot oil passages 58, 58 ′ of the right running remote control valve 51 b, and a second shuttle valve 102 is provided in the second communicating pilot oil passage 92.

  The first communication pilot oil passage 91 is connected to the third communication pilot oil passage 93 via the first shuttle valve 101, and the second communication pilot oil passage 92 is connected to the fourth communication pilot oil passage 94 via the second shuttle valve 102. It is connected. The third and fourth communication pilot oil passages 93 and 94 are connected to a first regulator pilot oil passage 95 for outputting pilot pressure to a regulator valve R described later via a third shuttle valve 103.

  The first to third shuttle valves 101 to 103 are configured to guide the higher one of the acting hydraulic pressures to the third and fourth communication pilot oil passages 93 and 94 and the first regulator pilot oil passage 95. . For this reason, the regulator valve R includes the hydraulic pressure in the first and second communication pilot oil passages 91 and 92 selected by the first and second shuttle valves 101 and 102, that is, the left traveling pilot oil passages 57 and 57 ′ and The higher hydraulic pressure (hereinafter referred to as pilot secondary pressure) of the hydraulic pressure in the right traveling pilot oil passages 58, 58 'acts as the pilot pressure.

  The control valve group 60 includes a left travel control valve 61a driven by the pilot pressure output from the left travel remote control valve 51a, a right travel control valve 61b driven by the pilot pressure output from the right travel remote control valve 51b, The boom control valve 63 driven by the pilot pressure output from the boom remote control valve 53, the arm control valve 64 driven by the pilot pressure output from the arm remote control valve 54, and the pilot pressure output from the bucket remote control valve 55 And a swing control valve 66 driven by a pilot pressure output from the swing remote control valve 56. The hydraulic pressure supplied from the hydraulic pump P (hereinafter referred to as pump pressure). ) To control each hydraulic actuator To operate the Yueta. In FIG. 1, the boom control valve 63, the arm control valve 64, the bucket control valve 65, and the turning control valve 66 are not shown, and only the left and right traveling control valves 61a and 61b are shown.

  Each of the control valves 61a, 61b, 63 to 66 is a directional control valve at a 4-port 3 position, and is connected to the hydraulic pump P through a pump pressure oil passage 70. The left travel control valve 61a is connected to a first oil passage 71 that branches from the pump pressure oil passage 70 and supplies pump pressure, and a pair that connects the first oil passage 71 between the left travel motor 81a and the left travel control valve 61a. The left traveling oil passages 67 and 67 'are communicated with each other. A first communication oil passage 121 is provided between the left traveling oil passages 67 and 67 ′, and a fourth shuttle valve 104 is provided in the first communication oil passage 121.

  The right travel control valve 61b is branched from the pump pressure oil passage 70 and is connected to a second oil passage 72 that supplies pump pressure, and a pair of the second oil passage 72 is connected between the right travel motor 81b and the right travel control valve 61b. The right running oil passages 68 and 68 'are communicated with each other. A second communication oil passage 122 is provided between the right traveling oil passages 68 and 68 ′, and a fifth shuttle valve 105 is provided in the second communication oil passage 122.

  Although not shown in FIG. 1, the boom control valve 63, the arm control valve 64, and the bucket control valve 65 are branched from the pump pressure oil passage 70 to supply pump pressure. The third to fifth oil passages are connected to one of a pair of cylinder oil passages connected to the bottom chambers and rod chambers of the cylinders 83, 84, and 85 and between the control valves. Between the cylinder oil passages, third to fifth communication oil passages are respectively provided, and sixth to eighth shuttle valves are provided in the third to fifth communication oil passages, respectively. The swing control valve 66 is branched from the pump pressure oil passage 70 and connected to a sixth oil passage that supplies pump pressure, and a pair of swing oils connecting the sixth oil passage between the swing motor 86 and the swing control valve 66. Communicate with either side of the road. A sixth communication oil passage is provided between the swirling oil passages, and a ninth shuttle valve is provided in the sixth communication oil passage.

  The first communication oil passage 121 is connected to the seventh communication oil passage 127 via the fourth shuttle valve 104, and the second communication oil passage 122 is connected to the eighth communication oil passage 128 via the fifth shuttle valve 105. The seventh and eighth communication oil passages 127 and 128 are connected to the ninth communication oil passage 129 via the tenth shuttle valve 110, and the ninth communication oil passage 129 is piloted to the regulator valve R via the eleventh shuttle valve 111. It is connected to a second regulator pilot oil passage 135 for outputting pressure. The third to sixth communication oil passages are connected to the second regulator pilot oil passage 135 via the sixth to ninth shuttle valves, the tenth communication oil passage 130, the eleventh shuttle valve 111, and the like. The second regulator pilot oil passage 135 is connected to the opposite side of the first regulator pilot oil passage 95 in the regulator valve R.

  The fourth to eleventh shuttle valves 104 to 111 are configured to guide the higher one of the acting hydraulic pressures to the seventh to tenth communication oil passages 127 to 130 and the second regulator pilot oil passage 135. For this reason, the regulator valve R has the highest hydraulic pressure (hereinafter referred to as the highest load pressure) among the hydraulic pressures in the first to sixth communication oil passages selected by the fourth to ninth shuttle valves, that is, the load hydraulic pressure of each hydraulic actuator. Act as pilot pressure. This maximum load pressure acts on the regulator valve R from the direction facing the above-described pilot secondary pressure.

  A pump pressure oil passage 70 upstream of the first to sixth oil passages (hydraulic pump P side) for supplying pump pressure to each control valve is branched from the oil passage 70 and connected to the regulator valve R. An oil passage 77 and an eighth oil passage 78 are provided, and a flow control valve 140 is provided in the seventh oil passage 77. Further, a third regulator pilot oil passage for branching from the oil passage 70 and outputting the pump pressure as a pilot pressure to the regulator valve R is provided upstream of the first to sixth oil passages. 79 is provided. The pump pressure output via the third regulator pilot oil passage 79 acts on the regulator valve R from the same direction as the pilot secondary pressure described above, that is, from the direction opposite to the maximum load pressure described above.

  The flow rate control valve 140 is a proportional flow rate control valve that is driven according to the pump pressure in the pump pressure oil passage 70 (seventh oil passage 77). When the pump pressure exceeds a predetermined pressure, the pressure oil is supplied to the regulator valve R. And is discharged to a capacity cylinder 151 (to be described later) via a regulator valve R, thereby reducing the discharge amount of the hydraulic pump P and preventing engine stall at high loads.

  The pump control means 150 generates a hydraulic pressure to be supplied to the displacement cylinder 151 using the displacement cylinder 151 that changes the variable displacement of the hydraulic pump P using the hydraulic pressure, and the above-described maximum load pressure, pilot secondary pressure, and pump pressure. And a regulator valve R.

  The displacement cylinder 151 has a plunger 152 slidably disposed therein and connected to the swash plate S of the hydraulic pump P. The plunger 152 is driven by hydraulic pressure supplied from the regulator valve R (hereinafter referred to as displacement control pressure). Is configured to change the displacement of the hydraulic pump P by changing the inclination of the swash plate S. The rotational speed of the hydraulic pump P is constant, and the amount of oil discharged from the hydraulic pump P (pump pressure) varies by changing the inclination of the swash plate S.

  The regulator valve R has a spool slidably disposed therein, and the pump pressure in the pump pressure oil passage 70 acts on one first end portion of the spool, and the pilot secondary pressure described above is applied to the spool. Acting on one of the second ends, the above-mentioned maximum load pressure acts on the other end of the spool, the force acting on the spool by the pump pressure and the pilot secondary pressure, and the force acting on the spool by the maximum load pressure Due to the difference, the spool is slid to produce a capacity control pressure supplied to the capacity cylinder 151. The capacity control pressure generated by the regulator valve R is regulated to change the variable capacity of the hydraulic pump P in the capacity cylinder 151 so that the pump pressure is higher than the maximum load pressure by a predetermined pressure.

  The oil passage 155 that connects the displacement cylinder 151 and the regulator valve R is provided with a discharge oil passage 156 that branches from the oil passage 155 and connects to the oil tank T, and a throttle valve 157 is provided in the discharge oil passage 156. It has been.

  This oil passage 70 is connected to the pump pressure oil passage 70 upstream of the first to sixth oil passages for supplying pump pressure to each control valve (in the present embodiment, at the same position as the third regulator pilot oil passage 79). A relief oil passage 80 branched from the oil tank T and connected to the oil tank T is provided. The relief oil passage 80 is provided with a relief valve 160 for adjusting the pump pressure in the pump pressure oil passage 70 so as not to exceed a predetermined relief pressure.

  The operation of the hydraulic drive apparatus 100 configured as described above will be described in the case where the left and right traveling motors 81a and 81b are rotationally driven to move the vehicle. First, when the left and right traveling operation levers 27a and 27b are operated, operation signals are input from the operation detectors 27as and 27bs of the operation levers to the controller 40 (see FIG. 3). Command signals corresponding to the operation direction and the operation amount are output to the left and right traveling remote control valves 51a and 51b, respectively.

  Receiving the command signal, the left travel remote control valve 51a outputs a pilot pressure corresponding to the operation direction and operation amount of the left travel operation lever 27a to the left travel control valve 61a via the left travel pilot oil passages 57 and 57 '. . The left travel control valve 61a is driven according to the pilot pressure, and communicates the first oil passage 71 branched from the pump pressure oil passage 70 to either one of the left travel oil passages 67 and 67 'from the hydraulic pump P. The supplied pump pressure is supplied to the left traveling motor 81a, and the left traveling motor 81a is rotationally driven.

  The right traveling remote control valve 51b that has received the command signal applies a pilot pressure corresponding to the operation direction and the operation amount of the right traveling operation lever 27b to the right traveling control valve 61b via the right traveling pilot oil passages 58 and 58 '. Output. The right travel control valve 61b is driven according to the pilot pressure, and communicates the second oil passage 72 branched from the pump pressure oil passage 70 to either one of the right travel oil passages 68 and 68 'from the hydraulic pump P. The supplied pump pressure is supplied to the right traveling motor 81b, and the right traveling motor 81b is driven to rotate.

  At this time, the hydraulic pressures in the left traveling oil passages 67 and 67 ′ and the right traveling oil passages 68 and 68 ′ that supply hydraulic pressure to the left and right traveling motors 81a and 81b are the first and second communication oil passages 121 and 122, It is transmitted to the second regulator pilot oil passage 135 via the seventh to ninth communication oil passages 127 to 129, the fourth and fifth shuttle valves 104 and 105, and the tenth and eleventh shuttle valves 110 and 111. The second regulator pilot oil passage 135 is also adapted to transmit the oil pressure in each oil passage supplying hydraulic pressure to each cylinder 83 to 85 and the swing motor 86 of the work device 3, and is the largest of the load oil pressure of each hydraulic actuator. High hydraulic pressure (maximum load pressure) acts as a pilot pressure on the regulator valve R via the second regulator pilot oil passage 135.

  The hydraulic pressures in the left traveling pilot oil passages 57 and 57 'and the right traveling pilot oil passages 58 and 58' that output pilot pressure to the left and right traveling control valves 61a and 61b are the first to fourth communication pilot oil passages 91. To 94 and the first to third shuttle valves 101 to 103 are transmitted to the first regulator pilot oil passage 95, and the higher one of the oil pressure in the left and right traveling pilot oil passages (pilot secondary pressure) is the first. It acts as a pilot pressure on the regulator valve R from the direction facing the maximum load pressure via the regulator pilot oil passage 95.

  Further, the pump pressure in the pump pressure oil passage 70 acts as a pilot pressure on the regulator valve R from the same direction as the pilot secondary pressure via the third regulator pilot oil passage 79, that is, the direction facing the maximum load pressure. .

  Therefore, the regulator valve R creates a displacement control pressure that is supplied to the displacement cylinder 151 by moving the spool due to the difference between the force acting on the spool by the pump pressure and the pilot secondary pressure and the force acting on the spool by the maximum load pressure. The cylinder 151 receives the displacement control pressure and changes the variable displacement of the hydraulic pump P so that the pump pressure becomes higher than the maximum load pressure by a predetermined pressure. As a result, the hydraulic pump P discharges the required amount of oil that can drive the left and right traveling motors 81a and 81b against the load acting on the left and right traveling motors 81a and 81b.

  Here, assuming that the vehicle is moving in a state where the maximum load pressure is applied to the left and right traveling motors 81a and 81b, at least one of the left and right traveling operation levers 27a and 27b is suddenly operated from this state. The case will be described.

  First, when at least one of the left and right traveling operation levers 27a and 27b is suddenly operated, the hydraulic pressure in the traveling pilot oil passage that outputs the pilot pressure to the control valve is suddenly changed in response to the rapid operation. The pilot secondary pressure acting on the regulator valve R via the first regulator pilot oil passage 95 varies rapidly according to the variation.

  Specifically, if the left travel operation lever 27a is suddenly operated and the oil pressure in the left travel pilot oil passages 57, 57 'fluctuates more than the oil pressure in the right travel pilot oil passages 58, 58', The fluctuating oil pressure in the left traveling pilot oil passages 57, 57 ′ (hereinafter referred to as fluctuating pilot secondary pressure) acts as a pilot pressure on the regulator valve R via the first regulator pilot oil passage 95. On the other hand, when the right travel operation lever 27b is operated suddenly and the hydraulic pressure in the right travel pilot oil passages 58, 58 'fluctuates more than the hydraulic pressure in the left travel pilot oil passages 57, 57', the fluctuation occurs. The hydraulic pressure (variable pilot secondary pressure) in the right traveling pilot oil passages 58, 58 ′ acts as a pilot pressure on the regulator valve R via the first regulator pilot oil passage 95.

  Further, when at least one of the left and right traveling operation levers 27a and 27b is suddenly operated, the control valve is suddenly driven according to the rapid operation, and the hydraulic pressure in the pair of traveling oil passages connected to the traveling motor, that is, The load pressure acting on the travel motor fluctuates rapidly, and the maximum load pressure acting on the regulator valve R via the second regulator pilot oil passage 135 fluctuates rapidly according to the fluctuation. At this time, the fluctuation of the maximum load pressure is synchronized with the fluctuation of the pilot secondary pressure caused by the operation of the travel operation lever.

  Specifically, if the left travel operation lever 27a is operated suddenly and the load hydraulic pressure of the left travel motor 81a fluctuates more than the load pressure of the right travel motor 81b, the fluctuating load pressure of the left travel motor 81a ( (Hereinafter referred to as “variable maximum load pressure”) acts as a pilot pressure on the regulator valve R from the direction opposite to the above-described variable pilot secondary pressure via the second regulator pilot oil passage 135. On the other hand, when the right travel operation lever 27b is suddenly operated and the load hydraulic pressure of the right travel motor 81b fluctuates more than the load hydraulic pressure of the left travel motor 81a, the fluctuating load pressure of the right travel motor 81b (maximum variation). Load pressure) acts as a pilot pressure on the regulator valve R from the direction opposed to the variable pilot secondary pressure via the second regulator pilot oil passage 135.

  As described above, in the hydraulic drive device 100 according to the present invention, the load pressure of at least one of the left and right traveling motors 81a and 81b rapidly changes due to the operator's sudden operation, and the regulator valve R changes as the pilot pressure. When this occurs, the variable pilot secondary pressure that has changed in synchronism with this variable maximum load pressure acts on the regulator valve R as a pilot pressure from the direction facing the variable maximum load pressure. For this reason, when the load pressure of the traveling motor suddenly fluctuates due to the operator's sudden operation, the fluctuation of the maximum secondary pressure acting as the pilot pressure on the regulator valve R is canceled out by the fluctuation of the pilot secondary pressure. Therefore, it is possible to suppress a sudden change in the capacity control pressure generated by the regulator valve R. Accordingly, the left and right traveling motors 81a and 81b can be smoothly rotated without abruptly changing the amount of oil discharged from the hydraulic pump P, and hunting of the left and right traveling motors 81a and 81b can be suppressed. it can.

  In the first embodiment described above, as shown in FIG. 1, the left and right traveling pilot oils that output pilot pressure to the left and right traveling control valves 61a and 61b in order to reduce hunting of the left and right traveling motors 81a and 81b. Although the hydraulic pressure (pilot secondary pressure) in the passage is configured to act as the pilot pressure on the regulator valve R via the first regulator pilot oil passage 95, the present invention is not limited to such a configuration. For example, in order to reduce hunting of the swing motor 86, the hydraulic pressure in the swing pilot oil passage that outputs the pilot pressure to the swing control valve 66 may be applied to the regulator valve R as the pilot pressure. That is, the hydraulic pressure in the pilot oil passage that outputs the pilot pressure to the control valve that controls the supply of the hydraulic oil supplied to the hydraulic actuator whose hunting is to be reduced may be configured to act on the regulator valve as the pilot pressure.

  Next, a second embodiment of the hydraulic drive device according to the present invention will be described. In addition, about the component similar to 1st Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. As shown in FIGS. 3 and 4, the hydraulic drive device 200 includes the hydraulic pump P, the control valve group 60, the remote control valve group 50, the pump control means 150, and the highest hydraulic pressure among the load hydraulic pressures of the hydraulic actuators. A pressure sensor 205 for detecting (maximum load pressure), a load pressure control unit 210 for controlling a pilot pressure applied to the regulator valve R ′ based on a detection signal from the pressure sensor 205, and a pressure reducing valve 220. Is done.

  Similar to the first embodiment described above, the first communication oil passage 121 provided between the pair of left travel oil passages 67 and 67 ′ connected between the left travel motor 81 a and the left travel control valve 61 a is the fourth shuttle valve 104. Is connected to the seventh communication oil passage 127, and the second communication oil passage 122 provided between the pair of right travel oil passages 68, 68 'connected between the right travel motor 81b and the right travel control valve 61b is a fifth shuttle. It is connected to the eighth communication oil path 128 via the valve 105.

  The seventh and eighth communication oil passages 127 and 128 are connected to the ninth communication oil passage 129 via the tenth shuttle valve 110, and the ninth communication oil passage 129 is connected to the pressure sensor 205 via the eleventh shuttle valve 111. It is connected to the load pressure detection oil passage 201. In addition, although illustration is abbreviate | omitted in FIG. 4, the 3rd-5th communication oil path each provided in a pair of cylinder oil path connected between each cylinder and each control valve of the working device 3, and the turning motor 86, The sixth communicating oil passage provided in the pair of turning oil passages connected between the turning control valves 66 detects the load pressure via the sixth to ninth shuttle valves, the tenth communicating oil passage 130, the eleventh shuttle valve 111 and the like. It is connected to the oil passage 201.

  The fourth to eleventh shuttle valves 104 to 111 are configured to guide the higher one of the acting hydraulic pressures to the seventh to tenth communication oil passages 127 to 130 and the load pressure detection oil passage 201. For this reason, the pressure sensor 205 has the highest hydraulic pressure (maximum load pressure) among the hydraulic pressures in the first to sixth communication oil passages selected by the fourth to ninth shuttle valves, that is, the load hydraulic pressure of each hydraulic actuator. Input as detection pressure. The pressure sensor 205 is connected to the load pressure control unit 210 by an electric communication line (cable), detects the maximum load pressure of the load hydraulic pressure of each hydraulic actuator, and loads a detection signal corresponding to the maximum load pressure. The pressure is output to the pressure control unit 210.

  The load pressure control unit 210 generates a command signal based on the detection signal output from the pressure sensor 205, that is, the maximum load pressure of the load hydraulic pressure of each hydraulic actuator, and outputs the command signal to the pressure reducing valve 220. The operation of the pressure reducing valve 220 is controlled.

  The seventh oil passage 77 upstream of the flow control valve 140 is provided with a fourth regulator pilot oil passage 215 that branches from the oil passage 77 and outputs a pilot pressure to the regulator valve R ′. A pressure reducing valve 220 is provided in the regulator pilot oil passage 215. The fourth regulator pilot oil passage 215 is connected to the opposite side of the third regulator pilot oil passage 79 in the regulator valve R ′ (an oil passage for outputting a pump pressure as a pilot pressure to the regulator valve R ′). Therefore, the pilot pressure output via the fourth regulator pilot oil passage 215 acts on the regulator valve R ′ from the direction opposite to the pilot pressure (pump pressure) output via the third regulator pilot oil passage 79. To do.

  The pressure reducing valve 220 is an electromagnetic proportional pressure reducing valve that is driven in accordance with a command signal output from the load pressure control unit 210, adjusts the hydraulic pressure in the fourth regulator pilot oil passage 215 in accordance with the command signal, and The hydraulic pressure is configured to act as a pilot pressure on the regulator valve R ′. The pilot pressure acting on the regulator valve R ′ via the fourth regulator pilot oil passage 215 and the pressure reducing valve 220 is hereinafter referred to as feedback pressure.

  The regulator valve R ′ has a spool slidably disposed therein, the pump pressure in the pump pressure oil passage 70 acts on one end of the spool, and the feedback pressure described above is applied to the other end of the spool. Acting on the end portion, the spool is slid by the difference between the force acting on the spool by the pump pressure and the force acting on the spool by the feedback pressure, and the displacement control pressure supplied to the displacement cylinder 151 is created. . The capacity control pressure generated by the regulator valve R ′ is regulated so as to change the variable capacity of the hydraulic pump P in the capacity cylinder 151 so that the pump pressure is higher than the maximum load pressure by a predetermined pressure.

  The operation of the hydraulic drive device 200 configured as described above will be described in the case where the left and right traveling motors 81a and 81b are rotationally driven to move the vehicle. First, when the left and right traveling operation levers 27a and 27b are operated, operation signals are input to the controller 40 from the operation detectors 27as and 27bs of the respective operation levers as in the first embodiment described above (see FIG. 3). The control controller 40 outputs a command signal corresponding to the operation direction and the operation amount of each operation lever to the left and right traveling remote control valves 51a and 51b, respectively.

  The left and right traveling remote control valves 51a and 51b that have received the command signal apply pilot pressures according to the operation direction and the operation amount of the traveling operation levers 27a and 27b via the traveling pilot oil passages 57, 57 ', 58, and 58'. Output to the left and right travel control valves 61a and 61b, respectively. The left travel control valve 61a is driven according to the pilot pressure, and communicates the first oil passage 71 branched from the pump pressure oil passage 70 to either one of the left travel oil passages 67 and 67 'from the hydraulic pump P. The supplied pump pressure is supplied to the left traveling motor 81a, and the left traveling motor 81a is rotationally driven. Further, the right travel control valve 61b is driven according to the pilot pressure, and connects the second oil passage 72 branched from the pump pressure oil passage 70 to either one of the right travel oil passages 68 and 68 'to be a hydraulic pump. The pump pressure supplied from P is supplied to the right traveling motor 81b, and the right traveling motor 81b is driven to rotate.

  At this time, the hydraulic pressure in the left traveling oil passages 67, 67 ′ and the right traveling oil passages 68, 68 ′ for supplying pump pressure to the left and right traveling motors 81a, 81b is the first and second communication oil passages 121, 122, The pressure is transmitted to the load pressure detection oil passage 201 via the seventh to ninth communication oil passages 127 to 129, the fourth and fifth shuttle valves 104 and 105, and the tenth and eleventh shuttle valves 110 and 111. The load pressure detection oil passage 201 is also adapted to transmit the oil pressure in each oil passage supplying pump pressure to each of the cylinders 83 to 85 and the swing motor 86 of the working device 3, and is the most of the load oil pressure of each hydraulic actuator. High hydraulic pressure (maximum load pressure) is input to the pressure sensor 205 via the load pressure detection oil passage 201, and the pressure sensor 205 outputs a detection signal corresponding to the detected maximum load pressure to the load pressure control unit 210.

  Upon receiving the detection signal from the pressure sensor 205, the load pressure control unit 210 outputs a command signal created based on the detection signal to the pressure reducing valve 220, and the pressure reducing valve 220 receives the pump pressure oil passage 70 ( The hydraulic pressure (pump pressure) in the fourth regulator pilot oil passage 215 branched from the seventh oil passage 77) is adjusted. Thus, the hydraulic pressure (feedback pressure) adjusted by the pressure reducing valve 220 acts as a pilot pressure on the regulator valve R ′. Further, the pump pressure in the pump pressure oil passage 70 acts as a pilot pressure on the regulator valve R ′ from the direction opposed to the feedback pressure via the third regulator pilot oil passage 79.

  Therefore, the regulator valve R ′ creates a displacement control pressure that is supplied to the displacement cylinder 151 by moving the spool due to the difference between the force acting on the spool due to the pump pressure and the force acting on the spool due to the feedback pressure. In response to the displacement control pressure, the variable displacement of the hydraulic pump P is changed so that the pump pressure becomes higher than the maximum load pressure by a predetermined pressure. As a result, the hydraulic pump P discharges the required amount of oil that can drive the left and right traveling motors 81a and 81b against the load acting on the left and right traveling motors 81a and 81b.

  Here, assuming that the vehicle is moving in a state where the maximum load pressure is applied to the left and right traveling motors 81a and 81b, the load pressure of at least one of the left and right traveling motors 81a and 81b suddenly increases in that state. The case where it fluctuates is demonstrated.

  If the load pressure of at least one of the left and right traveling motors 81a and 81b, that is, the hydraulic pressure of at least one of the left traveling oil passages 67 and 67 'and the right traveling oil passages 68 and 68' fluctuates suddenly, The maximum load pressure in the detection oil passage 201 and the detection signal input to the load pressure control unit 210 via the pressure sensor 205 also change rapidly. At this time, based on the detection signal, the load pressure control unit 210 has a fluctuation rate of a feedback pressure adjusted by the pressure reducing valve 220 and applied to the regulator valve R ′ lower than the fluctuation rate of the maximum load pressure. Thus, a command signal to be output to the pressure reducing valve 220 is generated (for example, a command signal is generated using a signal having an opposite phase to the fluctuation of the maximum load pressure), and this command signal is output to the pressure reducing valve 220. Therefore, the pressure reducing valve 220 gradually adjusts the hydraulic pressure in the fourth regulator pilot oil passage 215, and the feedback pressure adjusted in this way (the feedback pressure having a fluctuation rate lower than the fluctuation rate of the maximum load pressure) is the pump pressure. Acting as a pilot pressure on the regulator valve R ′ from the opposite direction, the regulator valve R ′ creates a displacement control pressure supplied to the displacement cylinder 151, and the displacement cylinder 151 uses the displacement control pressure and the pump pressure is the highest load pressure. The variable capacity of the hydraulic pump P is changed so as to be higher than the predetermined pressure by a predetermined pressure.

  As described above, in the hydraulic drive device 200 according to the present invention, when the load pressure of the traveling motor suddenly fluctuates, the fluctuation rate of the feedback pressure that acts on the regulator valve R ′ as the pilot pressure is lower than the fluctuation rate of the load pressure. Since it is controlled so as to have a fluctuation rate, it is possible to suppress a sudden change in the capacity control pressure generated by the regulator valve R ′. Accordingly, the left and right traveling motors 81a and 81b can be smoothly rotated without abruptly changing the amount of oil discharged from the hydraulic pump P, and hunting of the left and right traveling motors 81a and 81b can be suppressed. it can.

  In the above-described second embodiment, as shown in FIG. 4, the fourth regulator pilot oil passage 215 is provided by branching from the seventh oil passage 77. The pump pressure oil passage 70 may be branched from the first to sixth oil passages (hydraulic pump P side) for supplying pump pressure to the control valve.

  Next, a third embodiment of the hydraulic drive device according to the present invention will be described. In addition, about the component similar to 1st Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. As shown in FIGS. 3 and 5, the hydraulic drive apparatus 300 outputs pilot pressure to the hydraulic pump P, the control valve group 60, the remote control valve group 50, the pump control means 150, and the regulator valve R ″. And an accumulator 310 provided in the second regulator pilot oil passage 135.

  An accumulator 310 is provided in the second regulator pilot oil passage 135 that guides the highest hydraulic pressure (maximum load pressure) of the load hydraulic pressure of each hydraulic actuator to the regulator valve R ″ as a pilot pressure. For this reason, the second regulator pilot is provided. The pilot pressure (maximum load pressure) output via the oil passage 135 acts on the regulator valve R ″ from a direction opposite to the pilot pressure (pump pressure) output via the third regulator pilot oil passage 79. Acts on the accumulator 310.

  The regulator valve R ″ has a spool slidably disposed therein, and the pump pressure in the pump pressure oil passage 70 acts on one end of the spool, and the above-described maximum load pressure is applied to the other end of the spool. The volume control pressure supplied to the capacity cylinder 151 is generated by sliding the spool by the difference between the force acting on the spool by the pump pressure and the force acting on the spool by the maximum load pressure. The capacity control pressure generated by the regulator valve R ″ is regulated to change the variable capacity of the hydraulic pump P in the capacity cylinder 151 so that the pump pressure is higher than the maximum load pressure by a predetermined pressure. .

  The operation of the hydraulic drive apparatus 300 configured as described above will be described in the case where the left and right traveling motors 81a and 81b are rotationally driven to move the vehicle. First, when the left and right traveling operation levers 27a and 27b are operated, operation signals are input to the controller 40 from the operation detectors 27as and 27bs of the operation levers as in the first and second embodiments described above ( 3), the controller 40 outputs a command signal corresponding to the operation direction and the operation amount of each operation lever to the left and right traveling remote control valves 51a and 51b, respectively.

  The left and right traveling remote control valves 51a and 51b that have received the command signal apply pilot pressures according to the operation direction and the operation amount of the traveling operation levers 27a and 27b via the traveling pilot oil passages 57, 57 ', 58, and 58'. Output to the travel control valves 61a and 61b, respectively. The left travel control valve 61a is driven according to the pilot pressure, and communicates the first oil passage 71 branched from the pump pressure oil passage 70 to either one of the left travel oil passages 67 and 67 'from the hydraulic pump P. The supplied pump pressure is supplied to the left traveling motor 81a, and the left traveling motor 81a is rotationally driven. Further, the right travel control valve 61b is driven according to the pilot pressure, and connects the second oil passage 72 branched from the pump pressure oil passage 70 to either one of the right travel oil passages 68 and 68 'to be a hydraulic pump. The pump pressure supplied from P is supplied to the right traveling motor 81b, and the right traveling motor 81b is driven to rotate.

  At this time, the hydraulic pressure in the left traveling oil passages 67, 67 ′ and the right traveling oil passages 68, 68 ′ for supplying pump pressure to the left and right traveling motors 81a, 81b is the first and second communication oil passages 121, 122, It is transmitted to the second regulator pilot oil passage 135 via the seventh to ninth communication oil passages 127 to 129, the fourth and fifth shuttle valves 104 and 105, and the tenth and eleventh shuttle valves 110 and 111. The hydraulic pressure in each oil passage for supplying pump pressure to the cylinders 83 to 85 and the swing motor 86 of the work device 3 is also transmitted to the second regulator pilot oil passage 135, and among the load hydraulic pressure of each hydraulic actuator, The highest hydraulic pressure (maximum load pressure) acts as a pilot pressure on the regulator valve R ″ via the second regulator pilot oil passage 135 and also acts on the accumulator 310. Further, the pump pressure in the pump pressure oil passage 70 3 Acts as a pilot pressure on the regulator valve R from the direction opposed to the maximum load pressure via the regulator pilot oil passage 79.

  Therefore, the regulator valve R ″ creates a displacement control pressure that is supplied to the displacement cylinder 151 by moving the spool due to the difference between the force acting on the spool due to the pump pressure and the force acting on the spool due to the maximum load pressure. In response to the displacement control pressure, the variable displacement of the hydraulic pump P is changed so that the pump pressure is higher than the maximum load pressure by a predetermined pressure, so that the load acting on the left and right traveling motors 81a and 81b is resisted. Thus, the required amount of oil that can drive the left and right traveling motors 81a and 81b is discharged from the hydraulic pump P.

  Here, assuming that the vehicle is moving in a state where the maximum load pressure is applied to the left and right traveling motors 81a and 81b, the load pressure of at least one of the left and right traveling motors 81a and 81b suddenly increases in that state. The case where it fluctuates is demonstrated.

  If the load pressure of at least one of the left and right traveling motors 81a and 81b, that is, the hydraulic pressure of at least one of the left traveling oil passages 67 and 67 'and the right traveling oil passages 68 and 68' is suddenly changed, the second pressure is changed according to the change. The pilot pressure (maximum load pressure) acting on the regulator valve R ″ via the regulator pilot oil passage 135 also varies abruptly. The suddenly varied maximum load pressure is applied to the regulator valve R ″ by the pilot pressure. As well as acting on the accumulator 310. At this time, the accumulator 310 operates so as to absorb the fluctuation of the maximum load pressure. Therefore, the regulator valve R ″ generates a capacity control pressure supplied to the capacity cylinder 151 using the maximum load pressure whose fluctuation is suppressed by the accumulator 310, and the capacity cylinder 151 uses the capacity control pressure to generate a pump pressure. The variable displacement of the hydraulic pump P is changed so as to be higher than the maximum load pressure by a predetermined pressure.

  As described above, in the hydraulic drive device 300 according to the present invention, when the load hydraulic pressure of at least one of the left and right traveling motors 81a and 81b is suddenly changed, the maximum load pressure acting as the pilot pressure on the regulator valve R ″ is rapidly changed. Since the accumulator 310 operates so as to absorb the fluctuation amount of the maximum load pressure, it is possible to suppress a sudden change in the capacity control pressure generated by the regulator valve R ″. Therefore, the left and right traveling motors 81a and 81b can be smoothly rotated without abruptly changing the amount of oil discharged from the hydraulic pump P, and hunting of the left and right traveling motors 81a and 81b can be reduced. it can.

  In the second and third embodiments described above, each control valve is constituted by a hydraulic pilot type directional control valve driven by a pilot pressure (hydraulic pressure) output from each remote control valve. May be constituted by an electromagnetically operated directional control valve driven by an electric signal output from the controller in accordance with the operation direction and the operation amount of each operation lever.

  In the above-described embodiment, the case where the load pressure of the traveling motor suddenly fluctuates has been described. However, when the load hydraulic pressure of each of the cylinders 83 to 85 of the working device 3 and the swing motor 86 fluctuates rapidly, the same applies. Hunting can be reduced.

  In the above-described embodiment, as shown in FIG. 1 and the like, the oil passages 78 are arranged in the order of the eighth oil passage 78, the seventh oil passage 77, and the third regulator pilot oil passage 79 from the upstream side of the pump pressure oil passage 70. -79 are provided, but this is not particularly limited, and each oil passage 78-70 may be provided so as to guide the pump pressure in the pump pressure oil passage 70.

  In the above-described embodiment, the power shovel is shown as an example of the work machine to which the hydraulic drive device according to the present invention is applied. However, the present invention is not limited to the power shovel, and a deep foundation excavator, an earth auger, etc. The same effect can be applied to and the same effect can be obtained.

PS power shovel (work machine)
P Hydraulic pump R, R ', R "Regulator valve (Volume control pressure regulator)
61a Left travel control valve (hydraulic supply control means)
61b Right travel control valve (hydraulic supply control means)
81a Left travel motor (hydraulic actuator)
81b Right travel motor (hydraulic actuator)
95 1st regulator pilot oil passage (hydraulic fluctuation suppression means)
100, 200, 300 Hydraulic drive device 150 Pump control means 151 Capacity cylinder (pump capacity control means)
205 Pressure sensor (hydraulic fluctuation suppression means, load hydraulic pressure suppression means)
210 Load pressure control unit (hydraulic fluctuation suppression means, fluctuation suppression pressure regulation means)
220 Pressure reducing valve (hydraulic fluctuation suppressing means, fluctuation suppressing pressure adjusting means)
310 Accumulator (hydraulic fluctuation suppression means)

Claims (5)

A variable displacement hydraulic pump; a hydraulic actuator driven by pressure oil discharged from the hydraulic pump; and pump control means for controlling a discharge oil amount of the hydraulic pump by changing a capacity of the hydraulic pump. A hydraulic drive device,
The pump control means includes a pump capacity control means for changing a variable capacity of the hydraulic pump using a capacity control oil pressure, and a capacity control pressure adjusting means for producing the capacity control oil pressure using a load oil pressure acting on the hydraulic actuator. With
The displacement control oil pressure is regulated to change the variable capacity of the hydraulic pump so that the discharge oil pressure of the hydraulic pump is higher than the load oil pressure by a predetermined pressure,
The hydraulic drive apparatus according to claim 1, wherein the displacement control pressure adjusting means includes an oil pressure fluctuation suppressing means for generating the displacement control oil pressure by suppressing the influence of the load oil pressure fluctuation when the load oil pressure fluctuates. A hydraulic pressure supply control means for controlling the hydraulic pressure supplied from the hydraulic pump to the hydraulic actuator using a pilot hydraulic pressure supplied according to an operator operation input of an operator;
The hydraulic pressure fluctuation suppression means suppresses fluctuations in the load hydraulic pressure supplied to the capacity control pressure regulating means to produce the capacity control hydraulic pressure using fluctuations generated in the pilot hydraulic pressure in response to the actuator operation input. 2. The hydraulic drive apparatus according to claim 1, wherein the displacement control hydraulic pressure is generated by using the load hydraulic pressure in which the fluctuation is suppressed.   The hydraulic pressure fluctuation suppression means includes a load hydraulic pressure detection means for detecting the load hydraulic pressure, and a fluctuation lower than a fluctuation rate of the load hydraulic pressure based on a detection signal corresponding to the load hydraulic pressure detected by the load hydraulic pressure detection means. And a fluctuation suppression pressure adjusting means for generating a fluctuation suppression hydraulic pressure of the rate, and the displacement control hydraulic pressure generated by the fluctuation suppression pressure adjusting means is used to generate the displacement control hydraulic pressure. Item 2. The hydraulic drive device according to Item 1.   The hydraulic pressure fluctuation suppression means includes an accumulator provided in an oil passage of the load hydraulic pressure supplied to the capacity control pressure adjusting means to create the capacity control hydraulic pressure, and the load hydraulic pressure whose fluctuation is suppressed by the accumulator The hydraulic drive apparatus according to claim 1, wherein the hydraulic control apparatus is configured to generate the capacity-controlled hydraulic pressure using a pressure sensor.   A hydraulic drive device according to any one of claims 1 to 4 and a construction work device driven by the hydraulic actuator, wherein the construction work device is configured to perform a required work. Work machine.

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