JP2012159177A - Hydraulic driving device for work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently use pressure oil accumulated in an accumulator in view of energy-saving.SOLUTION: This hydraulic driving device for a work machine includes: a main hydraulic pump 21; a plurality of hydraulic actuators 11 to 14 using the main hydraulic pump 21 as a hydraulic source; a regeneration hydraulic motor 83 driven by return pressure oil of the specific hydraulic actuator 11; a regeneration hydraulic pump 84 to which an output of the regeneration hydraulic motor 83 is transmitted so that the hydraulic pump is driven; an accumulator 91 accumulating pressure oil discharged from the regeneration hydraulic pump 84; an accumulated pressure sensor 107 detecting a pressure of the pressure oil accumulated in the accumulator 91; a switching means (on-off valve 93 and pilot check valve 200) switching the hydraulic source of the predetermined hydraulic actuator 14 from the main hydraulic pump 21 to the accumulator 91; and a controller 110 controlling the same. The controller 110 causes the switching means to switch the hydraulic source on condition that the pressure detected by the accumulated pressure sensor 107 reaches a reference drive pressure required for driving the hydraulic actuator 14.

Description

  The present invention is a hydraulic drive device for a work machine such as a hydraulic excavator provided with a plurality of hydraulic actuators, and generates pressure oil using return pressure oil discharged from a specific hydraulic actuator, stores the pressure oil in an accumulator, and then The present invention relates to a hydraulic drive device for a work machine that uses pressure oil of an accumulator to drive a predetermined hydraulic actuator among a plurality of hydraulic actuators.

  The hydraulic excavator includes a revolving body coupled to a traveling body so as to be able to revolve, and a front working device provided at a front portion of the revolving body. The front working device includes a boom that is pivotably coupled to the front portion of the swing body, an arm that is pivotally coupled to the boom, and a bucket that is pivotally coupled to the bucket.

  A conventional hydraulic drive device of this hydraulic excavator includes a swing motor (hydraulic motor) that drives a swing body, a boom cylinder (hydraulic cylinder) that drives a boom, an arm cylinder (hydraulic cylinder) that drives an arm, and a bucket. Bucket cylinder (hydraulic cylinder) to be driven, hydraulic pump that discharges pressure oil supplied to these hydraulic actuators, an engine (internal combustion engine) that drives the hydraulic pump, and a swing motor, boom cylinder, arm cylinder from the hydraulic pump And a directional control valve for turning, a directional control valve for boom, a directional control valve for arm, and a directional control valve for bucket that control the flow of pressure oil supplied to each of the bucket cylinders.

  As a pressure oil recovery and reuse system applicable to this type of hydraulic drive device, there is one disclosed in Patent Document 1. The pressure oil recovery and reuse system includes a main hydraulic pump that supplies pressure oil to an actuator, a first circuit that is supplied with return pressure oil from the actuator, a first pump motor connected to the first circuit, and A pressure converter having a variable displacement type second pump motor that is mechanically coupled to the first pump motor and connected to the second circuit, and a discharge path of the first circuit and the main hydraulic pump are communicated with each other. A third circuit, a pressure accumulator provided in the second circuit, a regenerative valve for switching the third circuit between a state in which the pressure oil flow is allowed and a state in which the pressure oil flow is blocked, It comprises a sequence valve provided between the second pump / motor side and the discharge path of the main hydraulic pump rather than the pressure-accumulating valve in the second circuit.

Japanese Patent No. 3362258

  In the pressure oil recovery and reuse system disclosed in Patent Document 1, when it is assumed that the actuator is a boom cylinder, the fluid energy of the return pressure oil discharged from the boom cylinder contracted by gravity acting on the front working device is used as the boom. It can be used when driving a plurality of hydraulic actuators including cylinders. However, the pressure accumulator (hereinafter referred to as “accumulator”) is joined with the discharge oil of the main hydraulic pump, and the discharge pressure of the main hydraulic pump always acts on the actuator during the operation of the actuator. When the oil discharged from the hydraulic pump is sufficient for driving the actuator, the pressure oil accumulated in the accumulator cannot be effectively used from the viewpoint of energy saving.

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a hydraulic drive device for a working machine that can effectively use pressure oil stored in an accumulator from the viewpoint of energy saving. It is in.

  In order to achieve the above-described object, the hydraulic drive device for a work machine according to the present invention is configured as follows.

[1] A hydraulic drive device for a work machine according to the present invention includes a main hydraulic pump, a plurality of hydraulic actuators using the main hydraulic pump as a hydraulic source, and return pressure oil of a specific hydraulic actuator among these hydraulic actuators. A regenerative hydraulic motor that is driven, a regenerative hydraulic pump that is driven by the output of the regenerative hydraulic motor, and an accumulator that stores pressure oil discharged from the regenerative hydraulic pump. In the hydraulic drive apparatus, a pressure accumulation amount detecting means for detecting the pressure of the pressure oil stored in the accumulator, a switching means for switching the hydraulic source of the predetermined hydraulic actuator from the main hydraulic pump to the accumulator, and the switching means Control means for controlling, wherein the control means is a predetermined hydraulic actuator among the plurality of hydraulic actuators. On the condition that the pressure detected by the pressure accumulation amount detecting means has reached a reference driving pressure set in advance as a pressure value necessary for driving the actuator, the switching means is provided with a hydraulic source of the predetermined hydraulic actuator. The main hydraulic pump is switched to the accumulator.

  In the hydraulic drive device for a work machine described in “[1]”, the control unit detects an accumulated pressure amount at a reference drive pressure set in advance as a pressure value necessary for driving a predetermined hydraulic actuator among a plurality of hydraulic actuators. On the condition that the pressure detected by the means has reached, the switching means switches the hydraulic source of a predetermined hydraulic actuator from the main hydraulic pump to the accumulator. Thereby, a predetermined hydraulic actuator can be driven by the discharge oil of the accumulator instead of the discharge oil of the main hydraulic pump. In this way, the discharge oil of the accumulator is used to drive a predetermined hydraulic actuator without joining the discharge oil of the accumulator to the discharge oil of the main hydraulic pump, that is, the main hydraulic pump is driven to drive the predetermined hydraulic actuator. Since the predetermined hydraulic actuator is driven only by the discharge oil of the accumulator without applying the load, the discharge oil of the accumulator can be effectively used from the viewpoint of energy saving.

[2] A hydraulic drive device for a work machine according to the present invention is the hydraulic drive device for a work machine according to “[1]”, in which the switching means is a flow of pressure oil from the accumulator toward the predetermined hydraulic actuator. And a blocking means for blocking the flow of pressure oil from the main hydraulic pump toward the predetermined hydraulic actuator.

  In the hydraulic drive device for a work machine described in “[2]”, the switching unit permits the flow of pressure oil from the accumulator to the predetermined hydraulic actuator by the permitting unit, and from the main hydraulic pump to the predetermined hydraulic actuator. The flow of pressure oil is blocked by blocking means. As a result, the hydraulic source of the predetermined hydraulic actuator can be reliably switched from the main hydraulic pump to the accumulator.

[3] The hydraulic drive device for a work machine according to the present invention is the hydraulic drive device for a work machine according to “[2]”, wherein the blocking unit operates by using the discharge pressure of the accumulator as a pilot pressure, The valve is configured to prevent pressure oil from being guided from a main hydraulic pump to the predetermined hydraulic actuator.

  In the hydraulic drive device for a work machine described in “[3]”, since the blocking unit is a valve that operates using the discharge pressure of the accumulator as a pilot pressure, at a timing when the discharge pressure of the accumulator is guided to a predetermined hydraulic actuator, It is possible to prevent pressure oil from being guided from the main hydraulic pump to a predetermined hydraulic actuator.

[4] A hydraulic drive device for a work machine according to the present invention provides a command for operating the predetermined hydraulic actuator in the hydraulic drive device for a work machine according to any one of “[1]” to “[3]”. Command detecting means for detecting, wherein the control means detects the command by the command detecting means in addition to the condition, or sends the hydraulic source of the predetermined hydraulic actuator to the switching means from the main hydraulic pump. It is characterized by a condition for switching to an accumulator.

  In the hydraulic drive device for a work machine described in “[4]”, in addition to the conditions described in “[1]”, a command is detected by the command detection means, or a hydraulic source of a predetermined hydraulic actuator is used. This is a condition for switching from the main hydraulic pump to the accumulator. Thereby, the pressure of the pressure oil stored in the accumulator is high enough to drive the predetermined hydraulic actuator, and only when the predetermined hydraulic actuator operates, the hydraulic source of the predetermined hydraulic actuator is The main hydraulic pump can be switched to the accumulator.

[5] The hydraulic drive device for a work machine according to the present invention is the hydraulic drive device for a work machine according to any one of “[1]” to “[4]”, wherein the specific hydraulic actuator is a work machine work. A boom cylinder for driving a boom provided in the apparatus, wherein the return pressure oil is discharged from the boom cylinder when the boom is rotated downward.

  In the hydraulic drive device for a work machine described in “[5]”, the return pressure oil that drives the regenerative hydraulic motor is discharged from the boom cylinder when the boom is rotated downward. A part of the fluid energy is obtained by converting the potential energy of the working device including the boom by the boom cylinder. That is, according to the hydraulic drive device for a work machine described in “[5]”, the potential energy of the work device of the work machine can be used for driving a predetermined hydraulic actuator, and the load applied to the main hydraulic pump is equivalent to the potential energy. Can only be reduced.

  According to the hydraulic drive device for a work machine according to the present invention, a predetermined hydraulic actuator can be driven by the discharge oil of the accumulator instead of the discharge oil of the main hydraulic pump. In other words, the predetermined hydraulic actuator is driven only by the discharge oil of the accumulator without applying a load for driving the predetermined hydraulic actuator to the main hydraulic pump, so the discharge oil of the accumulator is effectively used from the viewpoint of energy saving. be able to.

1 is a left side view of a hydraulic excavator that is a work machine to which a hydraulic drive device according to a first embodiment of the present invention is applied. It is a figure showing the hydraulic drive concerning a 1st embodiment of the present invention. It is a flowchart which shows the process which concerns on control of the opening / closing operation valve performed with the controller shown in FIG. It is a figure which shows the hydraulic drive device provided with the switching valve as a blocking means instead of the pilot check valve shown in FIG. It is a figure which shows the hydraulic drive device which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the process which concerns on control of the opening / closing operation valve and regeneration selection valve which are performed by the controller shown in FIG. It is a figure which shows the hydraulic drive device which concerns on 3rd Embodiment of this invention. It is a flowchart which shows the process which concerns on control of the opening / closing operation valve performed with the controller shown in FIG. It is a flowchart which shows the process which concerns on control of the regeneration selection valve performed with the controller shown in FIG.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS.

  A hydraulic excavator 1 illustrated in FIG. 1 includes a traveling body 2 that travels by driving a crawler belt, a revolving body 3 that is coupled to the traveling body 2 via a swivel bearing 14, and a front portion of the revolving body 3. And a front working device 7 provided.

  The swing body 3 includes a cab 4 provided on the left side of the front working device 7, a machine room 5 provided behind the cab 4, and a counterweight 6 provided behind the machine room 5. It has. A swing motor 14 (hydraulic motor) coupled to an inner race (not shown) of the swing bearing 14 via a speed reducer is provided in the machine room 5.

  The front working device 7 includes a boom 8 that is pivotably coupled to the front portion of the swing body 3, an arm 9 that is pivotally coupled to the boom 8, and a bucket 10 that is pivotally coupled to the arm 9. Is a backhoe type front working device. The boom 8 is driven by a boom cylinder 11 (hydraulic cylinder), the arm 9 is driven by an arm cylinder 12 (hydraulic cylinder), and the bucket 10 is a bucket cylinder 13 (hydraulic cylinder). It is driven by.

  As shown in FIG. 2, the hydraulic drive device 20 according to the first embodiment includes a boom cylinder 11, an arm cylinder 12, a bucket cylinder 13, a swing motor 14, these boom cylinder 11, arm cylinder 12, bucket cylinder 13, and swing motor. The main hydraulic pump 21 which discharges the hydraulic fluid which drives 14 and the diesel engine 22 which drives this main hydraulic pump 21 are provided.

  The hydraulic drive unit 20 further includes a boom main supply circuit 30, an arm main supply circuit 40, and a bucket use between the main hydraulic pump 21 and the boom cylinder 11, arm cylinder 12, bucket cylinder 13, and swing motor 14. Each of the main supply circuit 50 and the turning main supply circuit 60 is provided.

  The boom main supply circuit 30 includes a discharge pipe 70 extending from the discharge port of the main hydraulic pump 21, a boom main supply pipe 31 extending from the discharge pipe 70 toward the boom cylinder 11, and the boom main supply circuit 31. A boom direction control valve 32 provided at the end of the supply pipe 31 on the boom cylinder 11 side, a bottom side pipe 33 extending from the boom direction control valve 32 to the bottom chamber 11a of the boom cylinder 11, and a boom And a rod chamber side pipe line 34 extending from the directional control valve 32 to the rod chamber 11b of the boom cylinder 11. The boom direction control valve 32 is a hydraulic pilot type three-position valve, and is a spring center type valve. The initial position of the boom direction control valve 32 is a neutral position (the central valve position in the figure), and the boom main supply pipe 31 and both the bottom chamber side pipe 33 and the rod chamber side pipe 34 are connected. It is a valve position which interrupts | blocks the flow of the pressure oil in between. The first operation position of the boom direction control valve 32 (the valve position on the left side in the figure) is such that the boom main supply pipe 31 is connected to the rod chamber side pipe 34 while the bottom chamber side pipe 33 is used for regeneration, which will be described later. The valve position communicates with the inlet of the pressure transducer 82 of the circuit 80. The second operating position of the boom direction control valve 32 (the valve position on the right side in the figure) is such that the main supply pipeline 31 for the boom communicates with the bottom chamber side pipeline 33 while the rod chamber side pipeline 34 is connected to the pressure converter 82. This is the valve position that communicates with the inlet. The boom direction control valve 32 is operated by the pilot pressure generated by the boom operation lever device 35.

  The arm main supply circuit 40 includes a discharge pipe 70 extending from the discharge port of the main hydraulic pump 21, an arm main supply pipe 41 extending from the discharge pipe 70 toward the arm cylinder 12, and the arm main supply circuit 41. An arm direction control valve 42 provided at an end of the supply pipe 41 on the arm cylinder 12 side, a bottom side pipe 43 extending from the arm direction control valve 42 to the bottom chamber 12a of the arm cylinder 12, and an arm And a rod chamber side conduit 44 extending from the directional control valve 42 to the rod chamber 12b of the arm cylinder 12. The arm direction control valve 42 is a hydraulic pilot type three-position valve, and is a spring center type valve. The initial position of the directional control valve for arm 42 is a neutral position (the central valve position in the figure), and the arm main supply pipe 41 and both the bottom chamber side pipe 43 and the rod chamber side pipe 44 are It is a valve position which interrupts | blocks the flow of the pressure oil in between. The first operating position of the arm direction control valve 42 (the valve position on the left side in the figure) is such that the arm main supply pipe 41 is communicated with the rod chamber side pipe 44 while the bottom chamber side pipe 43 is connected to the hydraulic oil tank 71. This is the valve position to communicate with. The second operating position of the arm directional control valve 42 (the valve position on the right side in the figure) is such that the arm main supply pipe 41 communicates with the bottom chamber side pipe 43 while the rod chamber side pipe 44 is connected to the hydraulic oil tank 71. This is the valve position to communicate with. The arm direction control valve 42 is operated by the pilot pressure generated by the arm operation lever device 45.

  The bucket main supply circuit 50 includes a discharge pipe 70 extending from the discharge port of the main hydraulic pump 21, a bucket main supply pipe 51 extending from the discharge pipe 70 toward the bucket cylinder 13, and the bucket main supply circuit 50. A bucket direction control valve 52 provided at an end of the supply pipe 51 on the bucket cylinder 13 side, a bottom side pipe 53 extending from the bucket direction control valve 52 to the bottom chamber 13a of the bucket cylinder 13, and a bucket And a rod chamber side conduit 54 extending from the directional control valve 52 to the rod chamber 13 b of the bucket cylinder 13. The bucket direction control valve 52 is a hydraulic pilot type three-position valve, and is a spring center type valve. The initial position of the bucket direction control valve 52 is a neutral position (the central valve position in the figure), and the bucket main supply line 51 and both the bottom chamber side pipe 53 and the rod chamber side pipe 54 are connected. It is a valve position which interrupts | blocks the flow of the pressure oil in between. The first operating position of the bucket direction control valve 52 (the valve position on the left side in the figure) is such that the bottom chamber side pipe 53 is connected to the hydraulic oil tank 71 while the bucket main supply pipe 51 communicates with the rod chamber side pipe 54. This is the valve position to communicate with. The second operation position of the bucket direction control valve 52 (the valve position on the right side in the figure) is such that the rod chamber side pipe 54 is connected to the hydraulic oil tank 71 while the bucket main supply pipe 51 is connected to the bottom chamber side pipe 53. This is the valve position to communicate with. The bucket direction control valve 52 is operated by a pilot pressure generated by the bucket operation lever device 55. The bucket operation lever device 55 shares the boom operation lever device 35 and the operation lever 35a.

  The turning main supply circuit 60 includes a turning main supply pipe 61 branched from the bucket main supply pipe 51 and extending toward the turning motor 14, and an end of the turning main supply pipe 61 on the turning motor 14 side. A turning direction control valve 62 provided in the section, a first input / output port side pipe 63 extending from the turning direction control valve 62 to the first input / output port 14 a of the turning motor 14, and the turning direction control valve 62. And a second inlet / outlet port side pipe line 64 extending to the second inlet / outlet port 14 b of the turning motor 14. The turning direction control valve 62 is a hydraulic pilot type three-position valve, and is a spring center type valve. The initial position of the turning direction control valve 62 is a neutral position (the central valve position in the figure), and the turning main supply pipe 61, the first inlet / outlet port side pipe 63, and the second inlet / outlet port side pipe 64. It is a valve position which interrupts | blocks the flow of the pressure oil between both. The first operating position of the turning direction control valve 62 (the valve position on the left side in the figure) is such that the first inlet / outlet port side pipe 63 is connected while the main supply pipe 61 for turning is in communication with the second inlet / outlet port side pipe 64. The valve position communicates with the hydraulic oil tank 71. The second operation position of the turning direction control valve 62 (the valve position on the right side in the figure) is such that the turning main supply pipe 61 is communicated with the first inlet / outlet port side pipe 63 while the second inlet / outlet port side pipe 64 is connected. The valve position communicates with the hydraulic oil tank 71. The turning direction control valve 62 is operated by the pilot pressure generated by the turning operation lever device 65. The turning operation lever device 65 shares the arm operation lever device 45 and the operation lever 45a.

  The boom main supply circuit 30 supplies pressure oil from the main hydraulic pump 21 to the boom cylinder 11 driven by gravity acting on the front working device 7. As can be seen by comparing the configuration of the main supply circuit 30 for the boom and the other main supply circuits 40, 50, 60, the return pressure oil discharged from the boom cylinder 11 by the gravity acting on the front working device 7 is: It is led to the inlet of the pressure transducer 82 through the return pipe 81 of the regenerative circuit 80. In the main supply circuits 40, 50 and 60 other than the boom main supply circuit 30, the return pressure oil is guided to the hydraulic oil tank 71.

  Each of the boom main supply conduit 31, the arm main supply conduit 41, and the bucket main supply conduit 51 includes check valves 72 to 74, respectively. As a result, the flow of pressure oil toward the main hydraulic pump 21 is prevented in each of the main supply pipelines 31, 41, 51.

  The hydraulic drive device 20 includes the above-described regeneration circuit 80. The regenerative circuit 80 is used for returning pressure oil discharged from the bottom chamber 11a of the boom cylinder 11 (specific hydraulic actuator) when the boom cylinder 11 contracts, that is, when the boom of the front working device 7 is lowered. The fluid energy is used to drive the turning motor 14 (predetermined hydraulic actuator). Details of the configuration of the regeneration circuit 80 will be described next.

  The regenerative circuit 80 is driven by the above-described return pipe 81 extending from the outlet of the boom direction control valve 32 and the return pressure oil supplied from the boom cylinder 11 through the return pipe 81 to generate pressure oil. The pressure converter 82 described above, an accumulator 91 that stores the pressure oil generated by the pressure converter 82, a sub-supply line 92 that guides the pressure oil from the accumulator 91 to the turning main supply line 61, and And an on-off valve 93 for opening and closing the auxiliary supply pipe line 92.

  The pressure converter 82 is a regenerative hydraulic motor 83 to which the return pressure oil of the boom cylinder 11 is supplied from the boom direction control valve 32, and a regenerative hydraulic pump that is driven by the output of the regenerative hydraulic motor 83 being transmitted. 84. The regenerative hydraulic motor 83 is a constant displacement pump, and the regenerative hydraulic pump 84 is a variable displacement hydraulic pump. The capacity of the regenerative hydraulic pump 84 is adjusted by a control piston 84a that can be controlled electrically. The maximum capacity of the regenerative hydraulic pump 84 is set to be approximately the same as the capacity of the regenerative hydraulic motor 83. The purpose of setting the maximum capacity is to generate pressure oil having substantially the same pressure and substantially the same flow rate as the return pressure oil from the boom cylinder 11. The minimum capacity of the regenerative hydraulic pump 84 is a pressure necessary for driving the turning motor 14 from the return pressure oil discharged from the boom cylinder 11 when the boom cylinder 11 contracts only by the gravity of the front working device 7, for example, turning. It is set to a size capable of generating pressure oil at a pressure required for starting the motor 14.

  The on-off valve 107 is operated by an on-off operation valve 94. The opening / closing operation valve 94 is a two-position valve of an electromagnetic pilot type and a spring return type. When the valve position of the opening / closing operation valve 94 is the initial position (lower valve position), the pressure in the auxiliary supply line 92 is supplied as a pilot pressure to the opening / closing valve 93, and the opening / closing valve 93 closes the auxiliary supply line 92. It is like that. When the valve position of the on-off operation valve 94 is the operating position (the upper valve position in the figure), the pilot pressure applied to the on-off valve 93 is returned to the hydraulic oil tank 71, and the on-off valve 93 is connected to the auxiliary supply pipe. The path 92 is opened. In addition, the valve body of the on-off valve 93 is a poppet, and thereby sufficient sealing property is secured to prevent leakage of the pressure oil stored in the accumulator 91.

  The accumulator 91 introduces oil discharged from the regenerative hydraulic pump 84 through the accumulator line 97. The pressure accumulating line 97 includes a check valve 99 that blocks the flow of pressure oil toward the regenerative hydraulic pump 84, and a relief valve 100 that can discharge pressure oil on the regenerative hydraulic pump 84 side from the check valve 99. Is provided. The relief valve 100 defines the upper limit of the pressure oil pressure stored in the accumulator 91. Further, a check valve 101 is provided in the auxiliary supply pipe line 92. This check valve 101 prevents the flow of pressure oil from the turning main supply line 60 toward the sub supply line 92.

  The hydraulic drive device 20 further includes a pilot check valve 200 in the main supply pipeline 61 for turning. The pilot check valve 200 operates using the pressure in the auxiliary supply line 92, that is, the discharge pressure of the accumulator 91 when the on-off valve 93 is opened as a pilot pressure. Is prevented from being guided to the turning motor 14 through the turning main supply pipe 61. The minimum operating pressure of the pilot check valve 200 is set to the reference driving pressure Pacl. A pilot pipe line 200 a for guiding pilot pressure to the pilot check valve 200 extends from the position of the auxiliary supply pipe line 92 on the accumulator 91 side to the pilot check valve 200 with respect to the check valve 101.

  The on-off valve 93 and the pilot check valve 200 constitute switching means for switching the hydraulic power source of the swing motor 14 from the main hydraulic pump 21 to the accumulator 91. The on-off valve 93 is permission means for permitting the flow of pressure oil from the accumulator 91 toward the turning motor 14 (predetermined hydraulic actuator) by opening the sub supply line 92, and the pilot check valve 200 is the main supply for turning. This is blocking means for blocking the flow of pressure oil from the main hydraulic pump 21 toward the swing motor 14 (predetermined hydraulic actuator) in the pipe line 60.

  The hydraulic drive device 20 further includes a boom lowering pilot pressure sensor 102. The boom lowering pilot pressure sensor 102 detects a boom lowering pilot pressure Pi_bo previously associated with a boom lowering operation command out of the boom pilot pressure generated by the boom operating lever device 35, and the boom lowering pilot pressure Pi_bo. The boom lowering command detection signal, which is an electrical signal corresponding to the above, is output.

  The hydraulic drive device 20 further includes a high-pressure priority type shuttle valve 103 and a turning pilot pressure sensor 104. One of the two inlets of the high-pressure priority shuttle valve 103 communicates with a pilot line that guides the turning pilot pressure corresponding to the left turn operation command generated by the turning operation lever device 65 to the turning direction control valve 62. The other is in communication with a pilot line that guides the turning pilot pressure corresponding to the right turning operation command generated by the turning operation lever device 65 to the turning direction control valve 62. The higher one of the pressures in the pilot pipes is led to the outlet of the high-pressure priority type shuttle valve 103. The turning pilot pressure sensor 104 detects the turning pilot pressure Pi_sw guided to the outlet, and outputs a turning command detection signal that is an electrical signal corresponding to the turning pilot pressure Pi_sw.

  The hydraulic drive device 20 is further provided in the return pipe 81 to detect the pressure P1 of return pressure oil from the boom cylinder 11 (hereinafter referred to as “return pressure P1”), and is an electric signal corresponding to the return pressure P1. A return pressure sensor 105 that outputs a return pressure detection signal, and a pressure oil pressure P2 (hereinafter referred to as “generated pressure P2”) that is provided in the accumulator 97 and is generated by the regenerative hydraulic pump 84 are detected and generated. A generated pressure sensor 106 that outputs a generated pressure detection signal that is an electrical signal corresponding to the pressure P2, and a pressure P3 of pressure oil stored in the accumulator 91 (hereinafter referred to as "accumulated pressure P3") are detected, and the accumulated pressure P3 And an accumulated pressure sensor 107 for outputting an accumulated pressure detection signal which is an electrical signal corresponding to the above.

  The hydraulic drive device 20 further includes a controller 110. The controller 110 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) for storing a control program, a RAM (Random Access Memory) as a storage area for information processing work performed by the CPU, and the like. A microcontroller that performs various processes related to the operation of the hydraulic drive unit 20 by executing a control program stored in a ROM by a CPU. The controller 110 receives the boom lowering command detection signal, the turning command detection signal, the return pressure detection signal, the generated pressure detection signal, and the accumulated pressure detection signal. It is like that.

  The controller 110 includes a boom lowering pilot pressure determination unit 111, a tilt control unit 112, a turning pilot pressure determination unit 113, an accumulated pressure determination unit 114, and an opening / closing control unit 115. These means 111 to 115 are means set by the control program.

  The boom lowering pilot pressure determining means 111 determines whether or not the detected value of the boom lowering pilot pressure Pi_bo indicated by the boom lowering command detection signal is equal to or higher than the minimum pilot pressure Pi_low for operating the boom direction control valve 32. Is.

  When the boom lowering pilot pressure determining unit 111 determines that the detected value of the boom lowering pilot pressure Pi_bo is equal to or higher than the minimum pilot pressure Pi_low, the tilt control unit 112 returns the return pressure P1 indicated by the return pressure detection signal. Based on the detected value, the tilt angle of the regenerative hydraulic pump 84 is controlled so that the detected value of the generated pressure P2 indicated by the generated pressure detection signal becomes the reference drive pressure Pacl. The reference drive pressure Pacl is set in advance as a pressure necessary for driving the swing motor 14, and is set to a pressure necessary for starting the swing motor 14 in the first embodiment. The reference driving pressure Pacl is stored in advance in the ROM of the controller 110. The tilt control means 112 controls the control piston 84a of the regenerative hydraulic pump 84 so that the discharge flow rate of the regenerative hydraulic pump 84 decreases when the detected value of the generated pressure P2 is lower than the reference drive pressure Pacl. In contrast, when the detected value of the generated pressure P2 is higher than the reference drive pressure Pacl, the control piston 84a is controlled so that the discharge flow rate of the regenerative hydraulic pump 84 increases.

  The accumulated pressure determination unit 114 determines whether or not the detected value of the accumulated pressure P3 indicated by the accumulated pressure detection signal is equal to or higher than the reference drive pressure Pacl.

  The turning pilot pressure determination means 113 has a detected value of the turning pilot pressure Pi_sw indicated by the turning command detection signal that is the lowest pilot pressure Pi_low for operating the turning direction control valve 62 (the same as the lowest pilot pressure of the boom direction control valve 32). Pressure value) or more. The turning pilot pressure determining means 113, the above-mentioned high-pressure priority type shuttle valve 103, and the above-mentioned turning pilot pressure sensor 104 send a command for operating the turning motor 14 (predetermined hydraulic actuator) to the left turning. Command detecting means for detecting whether the command or the command for turning right is used.

  The opening / closing control means 115 determines that the accumulated pressure determining means 114 determines that the detected value of the accumulated pressure P3 is equal to or higher than the reference drive pressure Pacl, and the detected value of the turning pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low. When two conditions, that is, the condition determined by the turning pilot pressure determining means 113 as being in the state, are satisfied, electric power is supplied to the opening / closing operation valve 94 to change the valve position of the opening / closing operation valve 94 to the operating position ( The valve position on the upper side in FIG.

  In addition, when the accumulated pressure determining means 114 determines that the detected value of the accumulated pressure P3 is not equal to or higher than the reference drive pressure Pacl, the open / close control means 115 does not supply power to the open / close operation valve 94 and does not supply power. The valve position of the opening / closing operation valve 94 is controlled to the initial position (lower valve position), thereby closing the opening / closing valve 93.

  The opening / closing control means 115 and the opening / closing operation valve 94 constitute control means for controlling the opening / closing valve 93 of the switching means, and among the plurality of hydraulic actuators such as the boom cylinder 11, the arm cylinder 12, the bucket cylinder 13, and the swing motor 14. The accumulated pressure P3 detected by the accumulated pressure sensor 107 (accumulated pressure detecting means) has reached a reference drive pressure Pacl set in advance as a pressure value necessary for driving the swing motor 14 (predetermined hydraulic actuator); On the condition that both the turning pilot pressure sensor 104 and the turning pilot pressure determination means 113, that is, the command is detected by the command detection means, the opening / closing valve 93 of the switching means is opened. The power source is switched from the main hydraulic pump 21 to the accumulator 91.

  Of the operations of the hydraulic drive device 20 according to the first embodiment, a case where the pressure oil stored in the accumulator 91 is used for driving the turning motor 14 will be described with reference to FIG.

  As shown in FIG. 3, the accumulated pressure determination means 114 of the controller 110 inputs the accumulated pressure detection signal from the accumulated pressure sensor 107 (step S1), and the detected value of the accumulated pressure Pac obtained from this accumulated pressure detection signal is It is determined whether or not the reference driving pressure Pacl has been reached (step S2). As a result of this determination, when the detected value of the accumulated pressure Pac has reached the reference drive pressure Pacl (Y in step S2), the turning pilot pressure determination means 113 of the controller 110 detects the turning command detection signal from the turning pilot pressure sensor 104. (Step S3), it is determined whether or not the detected value of the turning pilot pressure Pi_sw obtained from the turning command detection signal is equal to or higher than the minimum pilot pressure Pi_low, that is, whether or not the operation of the turning motor 14 is instructed. Perform (step S4). As a result of the determination, when the detected value of the turning pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low (Y in step S4), the opening / closing control means 115 of the controller 110 supplies power to the opening / closing operation valve 94, that is, the opening / closing operation. The valve 94 is turned on (ON), and the on-off valve 93 is opened (step S5). The routine then returns to step S1.

  When the on-off valve 93 is opened, the pressure oil is discharged from the accumulator 91 to the sub supply line 92. This pressure oil is introduced between the turning direction control valve 62 and the pilot check valve 200 of the turning main supply line 60 through the auxiliary supply line 92, and further led to the turning motor 14 through the turning direction control valve 62. . At the same time, the pressure in the auxiliary supply line 92, that is, the discharge pressure of the accumulator 91 is guided to the pilot check valve 200 through the pilot line 200 a as a pilot pressure, thereby operating the pilot check valve 200, and the main hydraulic pump 21. Is maintained in a state that prevents the flow of pressure oil from the motor to the turning motor 14 (predetermined hydraulic actuator). That is, when the on-off valve 93 is opened and the pilot check valve 200 is operated, the hydraulic power source of the swing motor 14 is switched from the main hydraulic pump 21 to the accumulator 91.

  In step S2, when the accumulated pressure determination unit 114 determines that the detected value of the accumulated pressure Pac has not reached the reference drive pressure Pacl, that is, the accumulated pressure Pac of the accumulator 91 is insufficient for driving the swing motor 14. Is determined (N in Step S2), the opening / closing control means 115 keeps the opening / closing operation valve 94 in the OFF state (Step S6), and thereby the opening / closing valve 93 is kept closed. The In step S4, when it is determined by the turning pilot pressure determining means 113 that the detected value of the turning pilot pressure Pi_sw has not reached the minimum pilot pressure Pi_low, that is, when the operation of the turning motor 14 is not commanded ( In step S4, N), the open / close control means 115 does not supply electric power to the open / close operation valve 94 (step S6), and thereby the open / close valve 93 is held closed. As a result, the hydraulic source of the turning motor 14 is held by the main hydraulic pump 21.

  That is, when the state where the accumulated pressure Pac of the accumulator 91 has reached the reference drive pressure Pacl continues when driving the turning motor 14, "Start → Step S1 → Step S2 → Step S3 → Step S4 → Step S5 → By repeating the “Return” routine, the hydraulic power source of the swing motor 14 is maintained in a state where the main hydraulic pump 21 is switched to the accumulator 91. When the accumulated pressure Pac of the accumulator 91 is lower than the reference drive pressure Pacl, the processing from step S2 to step S6 is performed, whereby the hydraulic power source of the swing motor 14 is returned from the accumulator 91 to the main hydraulic pump 21.

  According to the hydraulic drive device 20 according to the first embodiment, the following effects can be obtained.

  The hydraulic drive device 20 according to the first embodiment switches the hydraulic source of the swing motor 14 from the main hydraulic pump 21 to the accumulator 91 on condition that the detected value of the accumulated pressure Pac has reached the reference drive pressure Pacl. Thereby, the turning motor 14 can be driven by the discharge oil of the accumulator 91 instead of the discharge oil of the main hydraulic pump 21. Thus, the discharge oil of the accumulator 91 is used for driving the swing motor 14 without joining the discharge oil of the accumulator 91 to the discharge oil of the main hydraulic pump 21, that is, the swing motor 14 is driven by the main hydraulic pump 21. Since the turning motor 14 is driven only by the discharge oil of the accumulator 91 without applying a load for the operation, the discharge oil of the accumulator 91 can be effectively used from the viewpoint of energy saving.

  The hydraulic drive device 20 according to the first embodiment pilot-checks the flow of pressure oil from the main hydraulic pump 21 toward the swing motor 14 while allowing the flow of pressure oil from the accumulator 91 toward the swing motor 14 by the on-off valve 93. Block by valve 200. As a result, the hydraulic source of the swing motor 14 can be reliably switched from the main hydraulic pump 21 to the accumulator 91.

  In the hydraulic drive device 20 according to the first embodiment, since the pilot check valve 200 operates using the discharge pressure of the accumulator 91 as the pilot pressure, from the main hydraulic pump 21 at a timing when the discharge oil of the accumulator 91 is guided to the swing motor 14. It is possible to prevent the pressure oil from being guided to the swing motor 14.

  In the hydraulic drive device 20 according to the first embodiment, in addition to the condition that the detected value of the accumulated pressure Pac reaches the reference drive pressure Pacl, the swing pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low, that is, the swing motor The opening / closing valve 93 is opened under the condition that the operation 14 has been commanded. Thereby, the hydraulic pressure source of the swing motor 14 is transferred from the main hydraulic pump 21 to the accumulator 91 only when the accumulated pressure Pac of the accumulator 91 is high enough to drive the swing motor 14 and the swing motor 14 operates. Can be switched.

  In the hydraulic drive device 20 according to the first embodiment, the return pressure oil that drives the regenerative hydraulic motor 83 is discharged when the boom cylinder 11 contracts, and part or all of the fluid energy of the return oil is generated by the boom. The potential energy of the front working device 7 including 8 is converted by the boom cylinder 11. That is, according to the hydraulic drive device 20 according to the first embodiment, the potential energy of the front working device 7 can be used to drive the turning motor 14, and the load applied to the main hydraulic pump 21 can be reduced by an amount corresponding to the potential energy. it can. As a result, the load applied to the diesel engine 22 that drives the main hydraulic pump 21 can be reduced, which contributes to energy saving.

  In the hydraulic drive device 20 according to the first embodiment described above, the blocking means for blocking the flow of pressure oil in the direction from the main hydraulic pump 21 to the swing motor 14 in the swing main supply pipeline 60 is a pilot check valve. However, the blocking means in the present invention is not limited to the pilot check valve, and may be the switching valve 201 shown in FIG. The switching valve 201 is a hydraulic pilot type two-position valve and is a spring return type valve. The pilot pressure of the switching valve 201 is the pressure in the sub supply pipe 92 as in the pilot check valve 200 in the first embodiment, and is applied to the switching valve 201 by the pilot pipe 93 a extending from the sub supply pipe 92. The initial position of the switching valve 201 (the upper valve position in the figure) is from the sub supply line 92 while allowing the flow of pressure oil from the main hydraulic pump 21 to the swing motor 14 in the main supply line 60 for turning. This is a valve position that prevents the flow of pressure oil toward the main supply pipe 60 for turning. The operation position (lower valve position) of the switching valve 201 is such that the flow of pressure oil from the main hydraulic pump 21 toward the swing motor 14 in the swing main supply pipeline 60 is blocked from the sub supply pipeline 92. 14 is a valve position that permits the flow of the pressure oil toward 14.

  The switching valve 201 may be an electromagnetic pilot type instead of a hydraulic pilot type. In this case, when supplying power to the opening / closing operation valve 94, that is, when opening the opening / closing valve 93, the controller 110 supplies switching valve 201 with electric power to switch to the operating position (opening / closing control means). 115) is added.

  In the hydraulic drive device 20 according to the first embodiment, the predetermined hydraulic actuator is the swing motor 14, but the predetermined hydraulic actuator in the present invention is not limited to the swing motor, and hydraulic actuators other than the swing motor 14 are used. That is, the hydraulic excavator 1 may be any of the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13. The boom cylinder 11 may also serve as both a specific hydraulic actuator that discharges the return pressure oil that drives the regenerative hydraulic motor 83 and a predetermined hydraulic actuator that is driven by the discharge oil of the accumulator 91.

[Second Embodiment]
A hydraulic drive device according to a second embodiment of the present invention will be described with reference to FIGS. The description of the same components as those of the first embodiment among the components of the hydraulic drive device according to the second embodiment will be omitted.

  In the hydraulic drive device 300 according to the second embodiment, there are two predetermined hydraulic actuators that are driven using the accumulated pressure of the accumulator 91, that is, the turning motor 14 and the bucket cylinder 13 described above. The bucket cylinder 13 is a hydraulic actuator that is driven at a lower hydraulic pressure than the swing motor 14.

  The hydraulic drive device 300 according to the second embodiment includes a sub supply pipe 310 that is different from the sub supply pipe 92 in the first embodiment. The auxiliary supply pipe 310 extends from the accumulator 91 and is provided with a trunk pipe 311 provided with an on-off valve 93 in the middle, and the main supply pipe 61 for turning of the turning main supply circuit 60 from the side of the trunk pipe 311. A first branch pipe 312 for guiding pressure oil, a second branch pipe 313 for guiding pressure oil from the trunk pipe 311 side to the main supply pipe 51 for buckets, a trunk pipe 311, a first branch pipe 312, and And a supply destination switching valve 314 provided between the three members of the second branch pipe 313.

  The supply destination switching valve 314 guides the discharge oil of the accumulator 91 to only the swing motor 14 of the swing motor 14 and the bucket cylinder 13, and only the bucket cylinder 13 of the swing motor 14 and the bucket cylinder 13 of the swing motor 14 and the bucket cylinder 13. It is a valve that can be switched to a state that leads to Specifically, the supply destination switching valve 314 is a spring return type electromagnetic pilot type two-position valve, and the initial position of the supply destination switching valve 314 (the valve position on the right side in the figure) passes through the trunk line 311. The valve position communicates only with the first branch pipe 312 out of the one branch pipe 312 and the second branch pipe 313, and the operating position of the supply destination switching valve 314 (the valve position on the left side in the figure) is the trunk pipe. This is a valve position at which the passage 311 communicates only with the second branch conduit 313 among the first branch conduit 312 and the second branch conduit 313.

  Each of the first branch pipe 312 and the second branch pipe 313 is provided with check valves 315 and 316, respectively. The check valve 315 blocks the flow of pressure oil from the turning main supply pipeline 60 toward the first branch pipeline 312, and the check valve 316 is moved from the bucket main supply pipeline 51 to the second branch pipeline 313. Blocking the flow of pressure oil heading.

  The hydraulic drive device 300 further includes a high-pressure priority type shuttle valve 320, a bucket pilot pressure, in connection with the fact that the bucket cylinder 13 is included in a predetermined hydraulic actuator that is driven using the accumulated pressure Pac of the accumulator 91. And a sensor 321. One of the two inlets of the high-pressure priority type shuttle valve 320 communicates with a pilot line that guides the bucket pilot pressure corresponding to the bucket cloud operation command generated by the bucket operation lever device 55 to the bucket direction control valve 52. The other is in communication with a pilot line that guides the bucket pilot pressure corresponding to the bucket dump operation command generated by the bucket operating lever device 55 to the bucket direction control valve 52. The higher one of the pressures in the pilot lines is guided to the outlet of the high-pressure priority type shuttle valve 320. The bucket pilot pressure sensor 321 detects the bucket pilot pressure Pi_bk guided to the outlet, and outputs a bucket operation command detection signal that is an electrical signal corresponding to the bucket pilot pressure Pi_bk.

  The hydraulic drive device 300 according to the second embodiment includes a controller 330 that is different from the controller 110 in the first embodiment. The controller 330 includes bucket pilot pressure determination means 331 that is a means set by a control program. The bucket pilot pressure determining means 331 is configured to detect the lowest pilot pressure Pi_low (the lowest pilot pressure of the boom direction control valve 32) when the detected value of the bucket pilot pressure Pi_bk indicated by the bucket operation command detection signal activates the bucket direction control valve 52. It is determined whether the pressure value is equal to or higher than the same pressure value. The bucket pilot pressure determination means 331, the above-described high-pressure priority type shuttle valve 320, and bucket pilot pressure sensor 321 detect the operation command of the bucket 10 regardless of whether it is a bucket cloud command or a bucket dump command. Is configured.

  The controller 330 includes opening / closing control means 333 different from the first embodiment. The opening / closing control means 333 has a condition that the accumulated pressure determining means 114 determines that the detected value of the accumulated pressure P3 has reached the reference drive pressure Pacl, and the detected value of the turning pilot pressure Pi_sw is the lowest pilot pressure Pi_low. When two conditions, that is, the condition determined by the turning pilot pressure determining means 113 as being in the above state, are satisfied, power is supplied to the opening / closing operation valve 94 to operate the valve position of the opening / closing operation valve 94. The position (the upper valve position in the figure) is controlled to open the on-off valve 93. This function is the same as in the first embodiment.

  In addition to this function, the opening / closing control means 333 provides a condition that the accumulated pressure determination means 114 determines that the detected value of the accumulated pressure P3 has reached the reference drive pressure Pacl, and the detected value of the turning pilot pressure Pi_sw. Is determined by the turning pilot pressure determination means 113 that the pressure is not equal to or higher than the minimum pilot pressure Pi_low, and the bucket pilot pressure determination means 331 determines that the detected value of the bucket pilot pressure Pi_bk is equal to or higher than the minimum pilot pressure Pi_low. When the three conditions are satisfied, power is supplied to the opening / closing operation valve 94 to control the valve position of the opening / closing operation valve 94 to the operating position (upper valve position in the figure). Thus, the on-off valve 93 is opened.

  The controller 330 includes supply destination switching control means 334 that is a means set by the control program in relation to the supply destination switching valve 314 being provided. The supply destination switching control unit 334 is configured to switch the supply destination based on the determination result of the accumulated pressure determination unit 114 and the turning pilot pressure determination unit 113 or the determination result of the accumulation pressure determination unit 114 and the bucket pilot pressure determination unit 331. The valve 314 is controlled. Specifically, the condition that the accumulated pressure determining means 114 determines that the detected value of the accumulated pressure P3 has reached the reference drive pressure Pacl, and the detected value of the turning pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low. The supply destination switching control means 334 does not supply power to the supply destination switching valve 314 when the two conditions of the condition determined by the turning pilot pressure determination means 113 as being in the state are satisfied, and the supply destination switching is performed. The valve position of the valve 314 is maintained at the initial position (the valve position on the right side in the drawing), whereby the main conduit 311 is turned through the supply destination switching valve 314 and the first branch conduit 312 to the main supply conduit 60 for turning. To communicate with.

  The supply destination switching control means 334 further includes a condition that the accumulated pressure determining means 114 determines that the detected value of the accumulated pressure P3 has reached the reference drive pressure Pacl, and the detected value of the turning pilot pressure Pi_sw is the lowest pilot. The condition that the turning pilot pressure determining means 113 determines that the pressure is not equal to or higher than the pressure Pi_low, and the bucket pilot pressure determining means 331 determines that the detected value of the bucket pilot pressure Pi_bk is equal to or higher than the lowest pilot pressure Pi_low. When the three conditions are satisfied, power is supplied to the supply destination switching valve 314 to control the valve position of the supply destination switching valve 314 to the operating position (the valve position on the left side in the figure). Accordingly, the main conduit 311 is communicated with the bucket main supply conduit 51 through the supply destination switching valve 314 and the second branch conduit 313.

  The hydraulic drive device 300 further includes a first pilot check valve 340 provided in the turning main supply pipeline 61 and a second pilot check valve 341 provided in the bucket main supply pipeline 51. The first pilot check valve 340 uses the pilot pressure as the pressure in the first branch pipe 312 when the on-off valve 93 is open and the valve position of the supply destination switching valve 314 is the initial position, that is, the discharge pressure of the accumulator 91. In this operation, the oil discharged from the main hydraulic pump 21 is prevented from being guided to the turning motor 14 through the turning main supply pipeline 60. The minimum operating pressure of the first pilot check valve 340 is set to the reference driving pressure Pacl. In addition, the second pilot check valve 341 uses the pilot pressure as the pressure in the second branch pipe 313 in the state where the on-off valve 93 is open and the valve position of the supply destination switching valve 314 is the operating position, that is, the discharge pressure of the accumulator 91 In this operation, the oil discharged from the main hydraulic pump 21 is prevented from being guided to the bucket cylinder 13 through the bucket main supply line 51. The minimum operating pressure of the second pilot check valve 341 is also set to the reference driving pressure Pacl.

  In the hydraulic drive device 300 according to the second embodiment, the on-off valve 93, the supply destination switching valve 314, and the first pilot check valve 340 are switching means for switching the hydraulic source of the swing motor 14 from the main hydraulic pump 21 to the accumulator 91. Is configured. Further, the on-off valve 93 and the supply destination switching valve 314 open the trunk pipe line 311 of the sub-feed pipe 310 and connect the trunk pipe 311 to the first branch pipe 312 from the accumulator 91 to the turning motor 14 ( The first pilot check valve 340 is directed from the main hydraulic pump 21 to the turning motor 14 (predetermined hydraulic actuator) in the main supply pipeline 60 for turning. It is a blocking means for blocking the flow of pressure oil.

  The on-off valve 93, the supply destination switching valve 314, and the second pilot check valve 341 constitute switching means for switching the hydraulic source of the bucket cylinder 13 from the main hydraulic pump 21 to the accumulator 91. Further, the on-off valve 93 and the supply destination switching valve 314 open the trunk line 311 of the sub-feed line 310 and connect the trunk line 311 to the second branch line 313 to connect the bucket cylinder 13 ( The first pilot check valve 340 is directed from the main hydraulic pump 21 to the bucket cylinder 13 (predetermined hydraulic actuator) in the bucket main supply line 51. The permission means permits the flow of pressure oil toward the predetermined hydraulic actuator. It is a blocking means for blocking the flow of pressure oil.

  Next, among the operations of the hydraulic drive device 300 according to the second embodiment, FIG. 6 shows a case where the pressure oil stored in the accumulator 91 is used for driving the swing motor 14 and a case where it is used for driving the bucket cylinder 13. Will be described.

  As shown in FIG. 6, the accumulated pressure determination means 114 of the controller 330 inputs the accumulated pressure detection signal from the accumulated pressure sensor 107 (step S11), and the detected value of the accumulated pressure Pac obtained from this accumulated pressure detection signal is It is determined whether or not the reference driving pressure Pacl has been reached (step S12). As a result of this determination, if the detected value of the accumulated pressure Pac has reached the reference drive pressure Pacl (Y in step S12), the turning pilot pressure determination means 113 of the controller 330 causes the turning command pressure detection signal from the turning pilot pressure sensor 104 to be detected. (Step S13), it is determined whether or not the detected value of the turning pilot pressure Pi_sw obtained from the turning command detection signal is equal to or higher than the minimum pilot pressure Pi_low, that is, whether or not the operation of the turning motor 14 is commanded. Perform (step S14). As a result of the determination, when the detected value of the turning pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low (Y in step S14), the supply destination switching control means 334 of the controller 330 supplies power to the supply destination switching valve 314. The supply destination switching valve 314 is kept off, that is, the valve position of the supply destination switching valve 314 is held at the initial position, and the main pipeline 311 is connected to the supply destination switching valve in the sub supply pipeline 310. The state where the first branch pipe 312 is communicated with through 314 is maintained (step S15). Next, the open / close control means 333 of the controller 330 supplies power to the open / close operation valve 94, that is, the open / close operation valve 94 is turned on to open the open / close valve 93 (step S16). Then, the routine returns to step S11.

  When the on-off valve 93 is opened in a state where the valve position of the supply destination switching valve 314 is held at the initial position, pressure oil is discharged from the accumulator 91 to the main pipe line 311 of the sub supply pipe line 310. This pressure oil is guided between the turning direction control valve 62 of the turning main supply pipe 60 and the first pilot check valve 340 through the main pipe 311, the supply destination switching valve 314, and the first branch pipe 312. Further, it is guided to the turning motor 14 through the turning direction control valve 62. At the same time, the pressure in the first branch pipe 312, that is, the discharge pressure of the accumulator 91 is guided as pilot pressure to the first pilot check valve 340 through the pilot pipe 340 a, and thereby the first pilot check valve 340 operates. The pressure oil flow from the main hydraulic pump 21 toward the turning motor 14 (predetermined hydraulic actuator) is maintained. That is, when the valve position of the supply destination switching valve 314 is held at the initial position, the on-off valve 93 is opened and the first pilot check valve 340 is operated, whereby the hydraulic source of the swing motor 14 is transferred from the main hydraulic pump 21 to the accumulator. It was switched to 91.

  If the result of determination in step S14 is that the detected value of the turning pilot pressure Pi_sw is not equal to or higher than the minimum pilot pressure Pi_low (N in step S14), the bucket pilot pressure determination means 331 of the controller 330 A bucket operation command detection signal from the bucket pilot pressure sensor 321 is input, a detection value of the bucket pilot pressure Pi_bk is obtained from the bucket operation command detection signal (step S17), and the detection value of the bucket pilot pressure Pi_bk is the lowest pilot pressure. It is determined whether or not Pi_low or more, that is, whether or not the operation of the bucket cylinder 13 is commanded (step S18). As a result of this determination, when the detected value of the bucket pilot pressure Pi_bk is equal to or higher than the minimum pilot pressure Pi_low (Y in step S18), the supply destination switching control means 334 of the controller 330 supplies power to the supply destination switching valve 314. That is, the supply destination switching valve 314 is turned on (step S19). As a result, the valve position of the supply destination switching valve 314 is switched to the operating position, and the main pipeline 311 in the sub supply pipeline 310 is in communication with the second branch pipeline 313 through the supply destination switching valve 314 (step S19). ). Next, the opening / closing control means 333 of the controller 330 supplies power to the opening / closing operation valve 94, that is, turns on the opening / closing operation valve 94 and opens the opening / closing valve 93 (step S16). Then, the routine returns to step S11.

  In step S12, when the accumulated pressure determination unit 114 determines that the detected value of the accumulated pressure Pac has not reached the reference drive pressure Pacl, that is, the accumulated pressure Pac of the accumulator 91 is insufficient for driving the swing motor 14. (N in step S12), the supply destination switching control means 334 holds the supply destination switching valve 314 in the off state (step S20), and the opening / closing control means 333 turns off the opening / closing operation valve 94. The state is maintained (step S21). As a result, the trunk line 311 of the auxiliary supply line 310 is in communication with the first branch line 312 through the supply destination switching valve 314, but the on-off valve 93 is closed, so that the pressure oil is discharged from the accumulator 91. Therefore, the hydraulic power sources of the swing motor 14 and the bucket cylinder 13 are held by the main hydraulic pump 21.

  That is, when the hydraulic drive device 300 drives the swing motor 14, in a state where the accumulated pressure Pac of the accumulator 91 has reached the reference drive pressure Pacl, “Start → Step S11 → Step S12 → Step S13 → Step S14 → Step S15 → By repeating the routine of “Step S16 → Return”, the hydraulic source of the swing motor 14 is maintained in a state where the main hydraulic pump 21 is switched to the accumulator 91. Then, when the accumulated pressure Pac of the accumulator 91 is lower than the reference drive pressure Pacl, the hydraulic source of the swing motor 14 is returned from the accumulator 91 to the main hydraulic pump 21 by performing the process of step S21.

  Further, when the hydraulic drive device 300 drives the bucket 10 without driving the swing motor 14, in the state where the accumulated pressure Pac of the accumulator 91 has reached the reference drive pressure Pacl, “Start → Step S11 → Step S12 → Step S13 → By repeating the routine of step S14 → step S17 → step S18 → step S19 → step S16 → Return, the hydraulic source of the bucket cylinder 13 is maintained in a state where it is switched from the main hydraulic pump 21 to the accumulator 91. When the accumulated pressure Pac of the accumulator 91 is lower than the reference drive pressure Pacl, the process of step S21 is performed, whereby the hydraulic pressure source of the bucket cylinder 13 is returned from the accumulator 91 to the main hydraulic pump 21.

  According to the hydraulic drive apparatus 300 according to the second embodiment, the same effect as the first embodiment can be obtained, and the following effect can be obtained.

  The hydraulic drive device 300 according to the second embodiment is based on the condition that the detected value of the accumulated pressure Pac reaches the reference drive pressure Pacl not only when the swing motor 14 is driven but also when the bucket cylinder 13 is driven. Is switched from the main hydraulic pump 21 to the accumulator 91. Thereby, the bucket cylinder 13 can be driven by the discharge oil of the accumulator 91 instead of the discharge oil of the main hydraulic pump 21. Thus, the discharge oil of the accumulator 91 is used for driving the bucket cylinder 13 without joining the discharge oil of the accumulator 91 to the discharge oil of the main hydraulic pump 21, that is, the bucket cylinder 13 is driven by the main hydraulic pump 21. Since the bucket cylinder 13 is driven only by the discharge oil of the accumulator 91 without applying a load for the operation, the discharge oil of the accumulator 91 can be effectively used from the viewpoint of energy saving.

[Third Embodiment]
A hydraulic drive device according to a third embodiment of the present invention will be described with reference to FIGS. Description of the same components as those of the first and second embodiments among the components of the hydraulic drive device according to the third embodiment will be omitted.

  In the hydraulic drive device 400 according to the third embodiment, the sub supply circuit 410 includes a supply destination switching valve 414 different from the supply destination switching valve 314 in the second embodiment. The supply destination switching valve 414 guides the discharge oil of the accumulator 91 to both the swing motor 14 and the bucket cylinder 13, and guides the discharge oil of the accumulator 91 to only the swing motor 14 of the swing motor 14 and the bucket cylinder 13. It is a valve that can be switched between a state and a state in which the oil discharged from the accumulator 91 is guided only to the bucket cylinder 13 of the swing motor 14 and the bucket cylinder 13. Specifically, the supply destination switching valve 314 is a spring center type and electromagnetic pilot type three-position valve, and the initial position of the supply destination switching valve 414 (the central valve position in the figure) is the first through the trunk line 311. This is a valve position for communicating with both the branch line 312 and the second branch line 313, and the first operating position (the valve position on the right side in the drawing) of the supply destination switching valve 414 is the trunk line 311 in the first branch line. The second operating position of the supply destination switching valve 414 (the valve position on the left side in the drawing) is a valve position that allows the trunk line 311 to communicate with the second branch line 313. The supply destination switching valve 414 has solenoids 414a and 414b, and switches to the first operating position when power is supplied to the solenoid 414a, and switches to the second operating position when power is supplied to the solenoid 414b. It has become.

  The hydraulic drive device 400 according to the third embodiment further includes a controller 430 different from the second embodiment. The controller 430 has an opening / closing control means 433 and a supply destination switching control means 434 different from the opening / closing control means 333 and the supply destination control means 334 in the second embodiment in relation to the supply destination switching valve 414 being provided. And.

  The open / close control means 433 has a condition that the accumulated pressure determining means 114 determines that the accumulated pressure Pac has reached the reference drive pressure Pacl, and the detected value of the turning pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low. When two conditions, the condition determined by the turning pilot pressure determination means 113, are satisfied, power is supplied to the opening / closing operation valve 94 to change the valve position of the opening / closing operation valve 94 to the operating position (upper side in the figure). The valve position is controlled to open the on-off valve 93.

  The opening / closing control means 433 further includes a condition that the accumulated pressure determining unit 114 determines that the accumulated pressure Pac has reached the reference drive pressure Pacl, and a turning that the detected value of the turning pilot pressure Pi_sw is not equal to or higher than the minimum pilot pressure Pi_low. Three conditions are satisfied: the condition determined by the pilot pressure determining means 113 and the condition determined by the bucket pilot pressure determining means 331 that the detected value of the bucket pilot pressure Pi_bk is equal to or higher than the minimum pilot pressure Pi_low. Even in this case, power is supplied to the opening / closing operation valve 94 to control the valve position of the opening / closing operation valve 94 to the operating position (the upper valve position in the figure), thereby opening the opening / closing valve 93.

  The opening / closing control means 433 further includes a condition that the accumulated pressure determining unit 114 determines that the accumulated pressure Pac has reached the reference drive pressure Pacl, and a turning in which the detected value of the turning pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low. Three conditions are satisfied: the condition determined by the pilot pressure determining means 113 and the condition determined by the bucket pilot pressure determining means 331 that the detected value of the bucket pilot pressure Pi_bk is equal to or higher than the minimum pilot pressure Pi_low. Even in this case, power is supplied to the opening / closing operation valve 94 to control the valve position of the opening / closing operation valve 94 to the operating position (the upper valve position in the figure), thereby opening the opening / closing valve 93.

  Further, when the accumulated pressure determining means 114 determines that the detected value of the accumulated pressure P3 is not equal to or higher than the reference drive pressure Pacl, the open / close control means 433 does not supply power to the open / close operation valve 94 without performing power supply. The valve position of the opening / closing operation valve 94 is controlled to the initial position (lower valve position), thereby closing the opening / closing valve 93.

  The opening / closing control means 433 and the opening / closing operation valve 94 constitute control means for controlling the opening / closing valve 93 of the switching means, and among the plurality of hydraulic actuators such as the boom cylinder 11, the arm cylinder 12, the bucket cylinder 13, and the swing motor 14. In addition to the accumulated pressure P3 detected by the accumulated pressure sensor 107 (accumulated pressure detecting means) reaching the reference drive pressure Pacl set in advance as a pressure value necessary for driving the swing motor 14 (predetermined hydraulic actuator). The command is detected by at least one of the swing pilot pressure sensor 104 and the swing pilot pressure determination means 113 (command detection means), and the bucket pilot pressure sensor 321 and the bucket pilot pressure determination means 331 (command detection means). As a condition, the opening / closing valve 93 of the switching means is opened, that is, the switching means. The hydraulic pressure source of the swing motor 14 is made from the main hydraulic pump 21 so as to changeover switches to the accumulator 91.

  The controller 430 includes supply destination switching control means 434 that is a means set by the control program in association with the supply destination switching valve 414 being provided. The supply destination switching control means 434 controls the supply destination switching valve 414 based on the combination of the determination results of the accumulated pressure determination means 114, the turning pilot pressure determination means 113, and the bucket pilot pressure determination means 331. Specifically, the condition that the swing pilot pressure determining means 113 determines that the detected value of the swing pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low, and the detected value of the bucket pilot pressure Pi_bk is equal to or higher than the minimum pilot pressure Pi_low. The condition that the bucket pilot pressure determining unit 331 determines that the state is the state of the engine, and the condition that the stored pressure determining unit 114 determines that the detected value of the accumulated pressure P3 has reached the reference drive pressure Pacl. When the three conditions are satisfied, the supply destination switching control means 434 does not supply power to the supply destination switching valve 414, and the valve position of the supply destination switching valve 414 is set to the initial position (the central valve position in the figure). Thus, the main line 311 is held to both the first branch line 312 and the second branch line 313 through the supply destination switching valve 414, that is, the main supply line 60 for turning. And the main supply pipe line 51 for buckets.

  The condition that the detected value of the swing pilot pressure Pi_sw is determined not to be equal to or higher than the minimum pilot pressure Pi_low, and the detected value of the bucket pilot pressure Pi_bk is not equal to or higher than the minimum pilot pressure Pi_low. The supply destination switching control means 434 does not supply power to the supply destination switching valve 414 even when two conditions of the condition determined by the bucket pilot pressure determination means 331 are satisfied. The valve position is held at the initial position (the central valve position in the figure).

  The supply destination switching control means 434 further supplies the supply destination when one condition that the turning pilot pressure determination means 113 determines that the detected value of the turning pilot pressure Pi_sw is equal to or higher than the minimum pilot pressure Pi_low is satisfied. Electric power is supplied to the solenoid 414a of the switching valve 414, and the valve position of the supply destination switching valve 414 is controlled to the first operating position (the valve position on the right side in the figure), whereby the main line 311 is switched to the supply destination. The main supply pipe 60 for turning is communicated with the valve 414 and the first branch pipe 313.

  The supply destination switching control means 434 further includes one condition that the detected value of the turning pilot pressure Pi_sw is determined by the turning pilot pressure determining means 113 to be equal to or higher than the minimum pilot pressure Pi_low, and the detected value of the bucket pilot pressure Pi_bk. Is determined by the bucket pilot pressure determining means 331 to be equal to or higher than the minimum pilot pressure Pi_low, and the accumulated pressure determining means 114 determines that the detected value of the accumulated pressure P3 has reached the reference drive pressure Pacl. Even when the three conditions are satisfied, power is supplied to the solenoid 414a of the supply destination switching valve 414, and the valve position of the supply destination switching valve 414 is set to the first operating position (right side in the figure). Thus, the main conduit 311 is connected to the main supply conduit 60 for turning through the supply destination switching valve 414 and the first branch conduit 313. It is designed to pass through.

  The supply destination switching control means 434 further has a condition that the turning pilot pressure determining means 113 determines that the detected value of the turning pilot pressure Pi_sw is not equal to or higher than the minimum pilot pressure Pi_low, and the detected value of the bucket pilot pressure Pi_bk is the lowest. When two conditions, that is, the condition determined by the bucket pilot pressure determination means 331 that the state is equal to or higher than the pilot pressure Pi_low, are satisfied, power is supplied to the solenoid 414b of the supply destination switching valve 414, and the supply destination The valve position of the switching valve 414 is controlled to the second operating position (the valve position on the left side in the figure), whereby the main conduit 311 is supplied to the main bucket supply through the supply destination switching valve 414 and the second branch conduit 313. The pipe 51 is communicated.

  Next, among the operations of the hydraulic drive device 400 according to the third embodiment, a case where the pressure oil stored in the accumulator 91 is used for driving the swing motor 14 and a case where it is used for driving the bucket cylinder 13 is shown in FIG. This will be described with reference to FIG.

[1] The operation when supplying the discharged oil of the accumulator 91 to both the swing motor 14 and the bucket cylinder 13 will be described first.

  As shown in FIG. 8, the accumulated pressure determination means 114 of the controller 430 inputs the accumulated pressure detection signal from the accumulated pressure sensor 107 (step S31), and the detected value of the accumulated pressure Pac obtained from this accumulated pressure detection signal is It is determined whether or not the reference driving pressure Pacl has been reached (step S32). As a result of this determination, if the detected value of the accumulated pressure Pac has reached the reference drive pressure Pacl (Y in step S32), the turning pilot pressure determining means 113 of the controller 430 determines the turning command detection signal from the turning pilot pressure sensor 104. (Step S33), it is determined whether or not the detected value of the turning pilot pressure Pi_sw obtained from the turning command detection signal is equal to or higher than the minimum pilot pressure Pi_low, that is, whether or not the operation of the turning motor 14 is commanded. This is performed (step S34). Since the operation of the swing motor 14 is commanded this time (Y in Step S34), the opening / closing control means 433 of the controller 430 supplies power to the opening / closing operation valve 94, that is, turns on the opening / closing valve 93 (Step S34). S37), the on-off valve 93 is opened.

  The controller 430 performs the process shown in FIG. 9 in parallel with the process shown in FIG. The turning pilot pressure determination means 113 of the controller 430 inputs the turning command detection signal from the turning pilot pressure sensor 104 (step S41), and the detected value of the turning pilot pressure Pi_sw obtained from this turning command detection signal is the lowest pilot pressure. It is determined whether or not Pi_low or more, that is, whether or not the operation of the turning motor 14 is commanded (step S41). This time, the operation of the turning motor 14 is commanded (Y in step S41). Next, the bucket pilot pressure determination means 331 of the controller 430 inputs the bucket command detection signal from the bucket pilot pressure sensor 321 (step S43), and the detected value of the bucket pilot pressure Pi_bk obtained from this bucket command detection signal is It is determined whether or not the minimum pilot pressure is Pi_low or higher, that is, whether or not the operation of the bucket cylinder 13 is commanded (step S44). Since the operation of the bucket 10 is commanded this time (Y in step S44), the accumulated pressure determination means 114 of the controller 430 determines whether the detected value of the accumulated pressure Pac obtained in step S31 in FIG. 8 has reached the reference drive pressure Pacl. Since the current time is reached (Y in step S45), the supply destination switching control means 434 of the controller 430 does not supply power to the supply destination switching valve 414, that is, the supply destination switching valve. 414 is turned off (step S46), and the valve position of the supply destination switching valve 414 is held at the initial position (the central valve position in the figure).

  Step S37 in FIG. 8 is started after step S46 in FIG. As a result, the on-off valve 93 is opened in a state where the valve position of the supply destination switching valve 414 is held at the initial position, and as a result, pressure oil is discharged from the accumulator 91 to the main pipe line 311 of the sub supply pipe 310. As a result, pressure oil is guided from the main pipeline 311 between the turning direction control valve 62 of the turning main supply pipeline 60 and the first pilot check valve 340 through the supply destination switching valve 414 and the first branch pipeline 312. The pressure oil is guided to the turning motor 14 through the turning direction control valve 62. Similarly, pressure oil is supplied between the bucket direction control valve 52 of the bucket main supply pipeline 51 and the second pilot check valve 341 from the main pipeline 311 through the supply destination switching valve 414 and the second branch pipeline 313. The pressure oil is guided to the bucket cylinder 13 through the bucket direction control valve 52.

  At the same time, the pressure in the first branch pipe 312 (discharge pressure of the accumulator 91) is guided to the first pilot check valve 340 through the pilot pipe 340a as a pilot pressure, whereby the first pilot check valve 340 operates. The pressure oil flow from the main hydraulic pump 21 toward the turning motor 14 (predetermined hydraulic actuator) is maintained. Similarly, the pressure in the second branch pipe 313 (the discharge pressure of the accumulator 91) is guided as a pilot pressure to the second pilot check valve 341 through the pilot pipe 341a, and the second pilot check valve 341 is thereby operated. Thus, the flow of pressure oil from the main hydraulic pump 21 toward the bucket cylinder 13 (predetermined hydraulic actuator) is maintained.

  That is, when the valve position of the supply destination switching valve 414 is maintained at the initial position, the opening / closing valve 93 is opened and the first pilot check valve 340 and the second pilot check valve 341 are operated, whereby the swing motor 14 and the bucket cylinder Both of the hydraulic pressure sources 13 are switched from the main hydraulic pump 21 to the accumulator 91.

  When the hydraulic drive device 400 drives both the swing motor 14 and the bucket cylinder 13, in a state where the accumulated pressure Pac of the accumulator 91 has reached the reference drive pressure Pacl, “Start → Step S31 → Step S32 → Step” in FIG. The routine of “S33 → Step S34 → Step S37 → Return” is repeated, and “Start → Step S41 → Step S42 → Step S43 → Step S44 → Step S45 → Step S46 → Return” of FIG. 9 is repeated. The hydraulic power sources of both the swing motor 14 and the bucket cylinder 13 are held in a state where the main hydraulic pump 21 is switched to the accumulator 91. When the accumulated pressure Pac of the accumulator 91 falls below the reference driving pressure Pacl, the accumulated pressure determining means 114 of the controller 430 determines that the accumulated pressure Pac has not reached the reference driving pressure Pacl (N in step S32 in FIG. 8). Based on the result of this determination, the opening / closing control means 433 of the controller 430 stops supplying power to the opening / closing operation valve 94, and the opening / closing valve 93 is closed. As a result, the hydraulic pressure sources of both the swing motor 14 and the bucket cylinder 13 are returned from the accumulator 91 to the main hydraulic pump 21.

[2] Next, the operation when supplying the discharge oil of the accumulator 91 to only the swing motor 14 out of the swing motor 14 and the bucket cylinder 13 will be described first.

  In this case, the processing related to the control of the on-off valve 93 is performed by the routine of “Start → Step S31 → Step S32 → Step S33 → Step S34 → Step S37” in FIG. 8, as described in “(1)”. The on-off valve 93 is opened.

  On the other hand, regarding the processing related to the control of the supply destination switching valve 414, the processing from “Start → Step S41 → Step S42 → Step S43 → Step S44” in FIG. 9 is the same as “(1)”. In step S44, the bucket pilot pressure determination means 331 of the controller 430 determines that the detected value of the bucket pilot pressure Pi_bk is not equal to or higher than the minimum pilot pressure Pi_low, that is, the operation of the bucket cylinder 13 is not commanded ( N) in step S44. Based on the result of this determination, the supply destination switching control means 434 of the controller 430 supplies power to the solenoid 414a of the supply destination switching valve 414, that is, turns on the solenoid 414a (sol_a) and changes the valve position of the supply destination switching valve 414. Switch to the first operating position (valve position on the right side in the figure).

  Step S37 in FIG. 8 is started after step S47 in FIG. As a result, the on-off valve 93 is opened in a state where the valve position of the supply destination switching valve 414 is held at the first operating position, and as a result, the pressure oil is discharged from the accumulator 91 to the main pipe line 311 of the sub supply pipe 310. . As a result, pressure oil is guided from the main pipeline 311 between the turning direction control valve 62 of the turning main supply pipeline 60 and the first pilot check valve 340 through the supply destination switching valve 414 and the first branch pipeline 312. The pressure oil is guided to the turning motor 14 through the turning direction control valve 62. At this time, the main conduit 311 and the second branch conduit 313 are blocked by the supply destination switching valve 414, and the discharge pressure of the accumulator 91 is not guided to the bucket cylinder 13. Further, the first pilot check valve 340 is operated using the pressure in the first branch pipe 312 (discharge pressure of the accumulator 91) as a pilot pressure, and the pressure oil is directed from the main hydraulic pump 21 to the turning motor 14 (predetermined hydraulic actuator). It is held in a state that prevents the flow of

  That is, when the valve position of the supply destination switching valve 414 is held at the first operating position, the opening / closing valve 93 is opened, and the first pilot check valve 340 is operated. The 14 hydraulic sources were switched from the main hydraulic pump 21 to the accumulator 91.

  When the hydraulic drive device 400 drives only the swing motor 14 of the swing motor 14 and the bucket cylinder 13, in the state where the accumulated pressure Pac of the accumulator 91 has reached the reference drive pressure Pacl, “Start → Step S 31 → The routine of “Step S32 → Step S33 → Step S34 → Step S37 → Return” is repeated, and “Start → Step S41 → Step S42 → Step S43 → Step S44 → Step S47 →→ Return” of FIG. 9 is repeated. Thus, only the swing motor 14 is maintained in a state where the hydraulic pressure source is switched from the main hydraulic pump 21 to the accumulator 91. When the accumulated pressure Pac of the accumulator 91 falls below the reference driving pressure Pacl, the accumulated pressure determining means 114 of the controller 430 determines that the accumulated pressure Pac has not reached the reference driving pressure Pacl (N in step S32 in FIG. 8). Based on the result of this determination, the opening / closing control means 433 of the controller 430 stops supplying power to the opening / closing operation valve 94 (step S38), and the opening / closing valve 93 is closed. As a result, the hydraulic pressure source of the swing motor 14 is returned from the accumulator 91 to the main hydraulic pump 21.

[3] Next, the operation when supplying the discharged oil of the accumulator 91 only to the turning motor 14 will be described first.

  In this case, in the process related to the control of the on-off valve 93, in step S34, the turning pilot pressure determining means 113 of the controller 430 determines that the detected value of the turning pilot pressure Pi_sw is not equal to or higher than the minimum pilot pressure Pi_low (N in step S34). ). Next, the bucket pilot pressure determination means 331 of the controller 430 inputs the bucket command detection signal from the bucket pilot pressure sensor 321 (step S35), and the detected value of the bucket pilot pressure Pi_bk obtained from this bucket command detection signal is It is determined whether or not the minimum pilot pressure is Pi_low or higher, that is, whether or not the operation of the bucket cylinder 13 is commanded (step S36). Since the operation of the bucket cylinder 13 is commanded this time (Y in Step S36), the opening / closing control means 433 of the controller 430 supplies power to the opening / closing operation valve 94, that is, turns on the opening / closing valve 93 (Step S36). S37), the on-off valve 93 is opened.

  On the other hand, regarding the processing related to the control of the supply destination switching valve 414, the turning pilot pressure determination means 113 of the controller 430 determines in step S42 in FIG. N) in step S42. Next, the bucket pilot pressure determination means 331 of the controller 430 inputs the bucket command detection signal from the bucket pilot pressure sensor 321 (step S43), and the detected value of the bucket pilot pressure Pi_bk obtained from this bucket command detection signal is It is determined whether or not the minimum pilot pressure is Pi_low or higher, that is, whether or not the operation of the bucket cylinder 13 is commanded (step S49). Since the operation of the bucket cylinder 13 is commanded this time (Y in step S49), the supply destination switching control means 434 of the controller 430 supplies power to the solenoid 414b of the supply destination switching valve 414, that is, the solenoid 414b ( sol_b) is turned on, and the valve position of the supply destination switching valve 414 is switched to the second operating position (the valve position on the left side in the figure).

  Step S37 in FIG. 8 is started after step S50 in FIG. As a result, the opening / closing valve 93 is opened in a state where the valve position of the supply destination switching valve 414 is held at the second operating position, and as a result, pressure oil is discharged from the accumulator 91 to the main pipe line 311 of the sub supply pipe 310. . As a result, pressure oil is introduced from the main pipeline 311 between the bucket directional control valve 52 of the bucket main supply pipeline 51 and the second pilot check valve 341 through the supply destination switching valve 414 and the second branch pipeline 313. The pressure oil is guided to the bucket cylinder 13 through the bucket direction control valve 52. At this time, the main conduit 311 and the first branch conduit 312 are blocked by the supply destination switching valve 414, and the discharge pressure of the accumulator 91 is not guided to the swing motor 14. Further, the second pilot check valve 341 is operated using the pressure in the second branch pipe 313 (the discharge pressure of the accumulator 91) as a pilot pressure, and the pressure oil is directed from the main hydraulic pump 21 to the bucket cylinder 13 (predetermined hydraulic actuator). It is held in a state that prevents the flow of

  That is, when the valve position of the supply destination switching valve 414 is held at the second operating position, the on-off valve 93 is opened and the second pilot check valve 341 is operated, so that the bucket cylinder of the swing motor 14 and the bucket cylinder 13 is The 13 hydraulic sources were switched from the main hydraulic pump 21 to the accumulator 91.

  When the hydraulic drive device 400 drives only the bucket cylinder 13 of the swing motor 14 and the bucket cylinder 13, in the state where the accumulated pressure Pac of the accumulator 91 has reached the reference drive pressure Pacl, “Start → Step S 31 → The routine of Step S32 → Step S33 → Step S34 → Step S35 → Step S36 → Step S37 → Return is repeated and “Start → Step S41 → Step S42 → Step S48 → Step S49 → Step S50 → Return” of FIG. ”Is repeated, the hydraulic pressure source is maintained in a state where only the bucket cylinder 13 is switched from the main hydraulic pump 21 to the accumulator 91. When the accumulated pressure Pac of the accumulator 91 falls below the reference driving pressure Pacl, the accumulated pressure determining means 114 of the controller 430 determines that the accumulated pressure Pac has not reached the reference driving pressure Pacl (N in step S32 in FIG. 8). Based on the result of this determination, the opening / closing control means 433 of the controller 430 stops supplying power to the opening / closing operation valve 94 (step S38), and the opening / closing valve 93 is closed. As a result, the hydraulic pressure source of the swing motor 14 is returned from the accumulator 91 to the main hydraulic pump 21.

  According to the hydraulic drive device 400 according to the third embodiment, the same effects as those of the first and second embodiments can be obtained, and the following effects can be obtained.

  The hydraulic drive device 400 according to the third embodiment turns on the condition that the detected value of the accumulated pressure Pac reaches the reference drive pressure Pacl when the turning motor 14 and the bucket cylinder 13 are driven at the same time. The hydraulic pressure source for both the motor 14 and the bucket cylinder 13 can be switched from the main hydraulic pump 21 to the accumulator 91. Thereby, both the turning motor 14 and the bucket cylinder 13 can be driven by the discharge oil of the accumulator 91 instead of the discharge oil of the main hydraulic pump 21. Thus, the discharge oil of the accumulator 91 is used for driving the swing motor 14 and the bucket cylinder 13 without joining the discharge oil of the accumulator 91 to the discharge oil of the main hydraulic pump 21, that is, the main hydraulic pump 21 is swung. Since the turning motor 14 and the bucket cylinder 13 are driven only by the discharge oil of the accumulator 91 without applying a load for driving the motor 14 and the bucket cylinder 13, the discharge oil of the accumulator 91 is effectively used from the viewpoint of energy saving. be able to.

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 2 Running body 3 Revolving body 4 Operation room 5 Machine room 6 Counterweight 7 Front work device 8 Boom 9 Arm 10 Bucket 11 Boom cylinder 11a Bottom chamber 11b Rod chamber 12 Arm cylinder 12a Bottom chamber 12b Rod chamber 13 Bucket cylinder 13a Bottom chamber 13b Rod chamber 14 Swing motor 14a First inlet / outlet port 14b Second inlet / outlet port 15 Slewing bearing 20 Hydraulic drive device 21 Main hydraulic pump 22 Diesel engine 30 Boom main supply circuit 31 Boom main supply line 32 Boom direction control Valve 33 Bottom side pipe 34 Rod chamber side pipe 35 Boom operating lever device 35a Operating lever 40 Arm main supply circuit 41 Arm main supply pipe 42 Arm direction control valve 43 Bottom side pipe 44 Rod chamber side pipe Route 45 Arm control lever 45a Operation lever 50 Bucket main supply circuit 51 Bucket main supply line 52 Bucket direction control valve 53 Bottom side line 54 Rod chamber side line 55 Bucket operation lever device 60 Turning main supply circuit 61 Turning main Supply pipe line 62 Direction control valve 63 for swiveling First inlet / outlet port side pipe 64 Second inlet / outlet port side pipe 65 Turning lever device 70 Discharge pipe 71 Hydraulic oil tank 72 to 74 Check valve 80 Regenerative circuit 81 Return Pipe 82 Pressure converter 83 Regenerative hydraulic motor 84 Regenerative hydraulic pump 84a Control piston 90 Sub supply circuit 91 Accumulator 92 Sub supply pipe 93 Open / close valve 94 Open / close operation valve 95 Bypass pipe 96 Accumulation pipe 99 Check valve 100 Relief Valve 101 Check valve 102 Boom lowering pilot pressure sensor 103 High pressure priority type shuttle valve 04 Turning pilot pressure sensor 105 Return pressure sensor 106 Generated pressure sensor 107 Accumulated pressure sensor 110 Controller 111 Boom lowering pilot pressure determining means 112 Tilt control means 113 Turning pilot pressure determining means 114 Accumulated pressure determining means 115 Opening / closing control means 200 Pilot check valve 200a Pilot pipeline

300 Hydraulic Drive 310 Sub Supply Circuit 311 Main Pipe 312 First Branch Pipe 313 Second Branch Pipe 314 Supply Destination Switching Valves 315, 316 Check Valve 320 High Pressure Priority Shuttle Valve 321 Bucket Pilot Pressure Sensor 330 Controller 331 Bucket Pilot Pressure determining means 332 Accumulated pressure determining means 333 Opening / closing control means 334 Supply destination switching control means 340 First pilot check valve 340a Pilot line 341 Second pilot check valve 341a Pilot line

400 Hydraulic Drive 410 Sub Supply Circuit 414 Supply Destination Switching Valves 414a, 414b Solenoid 430 Controller 433 Opening / Closing Control Unit 434 Supply Destination Switching Control Unit

Claims (5)

A main hydraulic pump;
A plurality of hydraulic actuators using the main hydraulic pump as a hydraulic source;
Among these hydraulic actuators, a regenerative hydraulic motor driven by the return pressure oil of a specific hydraulic actuator,
A regenerative hydraulic pump that is driven by transmission of the output of the regenerative hydraulic motor;
In a hydraulic drive device for a work machine including an accumulator that stores pressure oil discharged from the regenerative hydraulic pump,
Pressure accumulation amount detecting means for detecting the pressure of the pressure oil stored in the accumulator;
Switching means for switching the hydraulic source of the predetermined hydraulic actuator from the main hydraulic pump to the accumulator;
Control means for controlling the switching means,
The control means is provided on the condition that the pressure detected by the pressure accumulation amount detecting means has reached a reference driving pressure preset as a pressure value necessary for driving a predetermined hydraulic actuator among the plurality of hydraulic actuators. A hydraulic drive device for a work machine, characterized in that the switching means switches the hydraulic source of the predetermined hydraulic actuator from the main hydraulic pump to the accumulator. The hydraulic drive device for a work machine according to claim 1,
The switching means includes permission means for permitting a flow of pressure oil from the accumulator toward the predetermined hydraulic actuator, and a blocking means for blocking a flow of pressure oil from the main hydraulic pump toward the predetermined hydraulic actuator. A hydraulic drive device for a working machine. The hydraulic drive device for a work machine according to claim 2,
The blocking means is a valve that is in a state of blocking pressure oil from being guided from the main hydraulic pump to the predetermined hydraulic actuator by operating the discharge pressure of the accumulator as a pilot pressure. Hydraulic drive device for work machines. In the hydraulic drive device of the working machine according to any one of claims 1 to 3,
Command detecting means for detecting a command to operate the predetermined hydraulic actuator;
In addition to the above conditions, the control means may be such that a command is detected by the command detection means or that the switching means switches the hydraulic source of the predetermined hydraulic actuator from the main hydraulic pump to the accumulator. A hydraulic drive device for a working machine. In the hydraulic drive device of the working machine according to any one of claims 1 to 4,
The specific hydraulic actuator is a boom cylinder that drives a boom provided in a working device of a work machine, and the return pressure oil is discharged from the boom cylinder when the boom is rotated downward. Hydraulic drive device for work machines.

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