Fluid pressure circuit

Abstract

Provided is a fluid pressure circuit which can suppress excessive feeding of a fluid to a main flow path of a switching valve side.　A fluid pressure circuit 130 comprises: a fluid feed source 2; an actuator device 5 operated by means of a fluid from the fluid feed source 2; and a switching valve 4 that is provided on a flow path 24-1 between the fluid feed source 2 and the actuator device 5 and that switches flow paths 24-2 and 25. The fluid pressure circuit 130 further comprises a flow dividing valve 91 that can cause at least a part of the fluid flowing from the fluid feed source 2 to the main flow path 24-1 of the switching valve 4 side to branch to a branch flow path 27. The flow dividing valve 91 is provided with a pressure compensation valve 92 that variably adjusts the opening of the branch flow path 27 in accordance with differential pressure between the main flow path 24-1 and the branch flow path 27, and that compensates for a flowrate to the branch flow path 27.

Description

【Technical Field】 【0001】 The present invention relates to a fluid pressure circuit, for example, a fluid pressure circuit that controls a fluid actuator according to an operation command. 【Background Art】 【0002】 Fluid pressure circuits that control fluid actuators according to operation commands are used in automobiles, construction machinery, cargo handling and transport vehicles, industrial machinery, and the like. For example, a hydraulic excavator expands and contracts a cylinder device by supplying pressure fluid from a hydraulic pump to a cylinder device connected to a hydraulic circuit as a fluid pressure circuit, thereby driving a load. 【0003】 As such a fluid pressure circuit, for example, there is one as described in Patent Document 1. The fluid pressure circuit of Patent Document 1 mainly includes a pump, a cylinder device, a switching valve connected between the pump and the cylinder device, and a flow dividing valve capable of branching a part of the pressure oil flowing from the pump to the main flow path on the cylinder device side into a branch flow path. When the switching valve is switched to the extension position by operating an operation lever, the pressure oil from the hydraulic pump is introduced into the bottom chamber of the cylinder device so that the rod extends from the cylinder. On the other hand, when it is switched to the contraction position by operating the operation lever of the remote control valve, the pressure oil from the hydraulic pump is introduced into the rod chamber of the cylinder device so that the rod contracts into the cylinder. When the switching valve is in the neutral position, the pressure oil from the hydraulic pump is returned to the tank through the flow dividing valve and the switching valve, and the rod does not operate. 【0004】 The flow dividing valve is a normally open type electromagnetic proportional control valve. When the operation lever is in the neutral position and the contraction position, the spool of the flow dividing valve is in the neutral position, and the entire amount of pressure oil from the pump is supplied to the main flow path on the cylinder device side. On the other hand, when the operation lever is operated to the extension position, the spool of the flow dividing valve changes from the neutral position to the flow dividing position, and the pressure oil from the pump is supplied to the main flow path and the branch flow path on the cylinder device side. 【Prior Art Documents】 [Patent Documents] 【0005】 [Patent Document 1] International Publication No. 2019 / 198579 (page 7, figure 7) [Overview of the Initiative] [Problems that the invention aims to solve] 【0006】 In the fluid pressure circuit of Patent Document 1, a flow divider valve is used to divert a portion of the pressurized oil flowing from the pump into the main channel to the branch channel, thereby adjusting the flow rate of pressurized oil supplied to the switching valve. However, in a fluid pressure circuit like the one in Patent Document 1, the pressure in the branch channel may fluctuate, and if the pressure in the branch channel becomes relatively higher than the pressure in the main channel, the pressurized oil from the pump may not flow easily to the branch channel, potentially leading to an excessive supply of pressurized oil to the main channel on the switching valve side. 【0007】 This invention was made in view of these problems, and aims to provide a fluid pressure circuit that can suppress the excessive supply of fluid to the main flow path on the switching valve side. [Means for solving the problem] 【0008】 To solve the above problems, the fluid pressure circuit of the present invention is A fluid supply source, An actuator device that operates using fluid from the aforementioned fluid supply source, A fluid pressure circuit comprising a switching valve provided in the flow path between the fluid supply source and the actuator device for switching the flow path, The system further includes a flow divider valve capable of diverting at least a portion of the fluid flowing from the fluid supply source to the main flow path on the switching valve side to a branch flow path. The aforementioned flow divider valve is equipped with a pressure compensation valve that variably adjusts the opening degree of the branch passage according to the differential pressure between the main passage and the branch passage, thereby compensating for the flow rate to the branch passage. According to this, the pressure compensation valve variably adjusts the opening degree of the branch passage according to the differential pressure between the main passage and the branch passage, and compensates for the flow rate to the branch passage, thereby suppressing the supply of excessive fluid to the main passage on the switching valve side when the switching valve is operated. 【0009】 The pressure compensation valve may be a pilot valve that operates based on the pilot pressure of the main flow path and the branch flow path. According to this, since the pressure compensation valve operates using pilot pressure, the structure of the pressure compensation valve is simple and it can reliably compensate for the flow rate to the branch channel. 【0010】 The housing of the flow divider valve and the housing of the pressure compensation valve may be integrated into one unit. According to this, the flow divider valve and pressure compensation valve can be made more compact. 【0011】 The flow diversion valve may consist of a housing having a first communication passage that connects the fluid supply source side flow path and the main flow path via the pressure compensation valve, and a second communication passage that connects the fluid supply source side flow path and the branch flow path via the pressure compensation valve, and a valve body that adjusts the opening degree of the second communication passage. According to this, since no valve body is provided in the first connecting passage from the fluid supply source to the pressure compensation valve, the fluid can pass through to the main flow path with minimal loss. 【0012】 The branch channel may be equipped with an auxiliary device that is operated by the fluid flowing through the branch channel. According to this, the fluid branched into the branched channel can be used to operate auxiliary equipment such as regenerative drive sources and accumulators. [Brief explanation of the drawing] 【0013】 [Figure 1] This figure shows a wheel loader incorporating a hydraulic circuit according to Embodiment 1 of the present invention. [Figure 2] This is a diagram showing the hydraulic circuit in Example 1. [Figure 3]It is a graph showing the relationship between the operating lever reverse stroke and the pilot secondary pressure. [Figure 4] It is a graph showing the relationship between the spool stroke and the opening area of the switching valve in Example 1. [Figure 5] It is a graph showing the relationship between the operating lever reverse stroke and the rod extension speed. [Figure 6] It is a graph showing the output characteristics of the generator according to the rotational speed of the regenerative motor. [Figure 7] It is a graph showing the relationship between the electrical signal from the controller and the priority flow rate in the flow dividing valve device. [Figure 8] It is a schematic diagram showing the state of the flow dividing valve device when the main hydraulic pump stops and the flow dividing valve is de-energized. [Figure 9] It is a schematic diagram showing the state of the flow dividing valve device when the main hydraulic pump operates and the flow dividing valve is de-energized. [Figure 10] It is a schematic diagram showing the state where the flow dividing valve is energized from the state of FIG. 9 when the differential pressure between the main flow path and the branch flow path is almost zero. [Figure 11] (a) is a schematic diagram showing the initial energized state where the flow dividing valve is energized from the state of FIG. 9 when the pressure in the branch flow path is higher than that in the main flow path, and (b) is a schematic diagram showing the state where the pressure compensation valve operates from the state of (a). [Figure 12] (a) is a schematic diagram showing the initial energized state where the flow dividing valve is energized from the state of FIG. 9 when the pressure in the branch flow path is lower than that in the main flow path, and (b) is a schematic diagram showing the state where the pressure compensation valve operates from the state of (a). [Figure 13] It is a graph showing the relationship between the spool stroke of the switching valve and the priority flow rate. [Figure 14] It is a diagram showing the hydraulic circuit in Example 2 of the present invention. [Figure 15] It is a graph showing the relationship between the spool stroke and the opening area of the switching valve in Example 2. 【Mode for Carrying Out the Invention】 【0014】 Embodiments for implementing the fluid pressure circuit according to the present invention will be described below based on examples. [Examples] 【0015】 A fluid pressure circuit according to Embodiment 1 of the present invention will be described with reference to Figures 1 to 13. 【0016】 The hydraulic circuit as a fluid pressure circuit according to Embodiment 1 is a hydraulic circuit that controls the stroke of a cylinder device in response to an operation command in work machinery, construction machinery, material handling vehicles, automobiles, etc., and is incorporated into the powertrain of a wheel loader 100 shown in Figure 1, for example. The wheel loader 100 mainly consists of a body 101, wheels 102 for travel, a work arm 103, a hydraulic cylinder 104, and a bucket 105 for holding gravel, etc. The body 101 is equipped with a mechanism 110 such as an engine, a fluid circuit 120 for travel, a hydraulic cylinder 104, and a hydraulic circuit 130 for work that drives a hydraulic cylinder 5, etc., which acts as an actuator device. 【0017】 As shown in Figure 2, the hydraulic circuit 130 mainly consists of a main hydraulic pump 2 as a fluid supply source driven by a drive mechanism 1 such as an engine or electric motor, a pilot hydraulic pump 3, a switching valve 4, a hydraulic cylinder 5, a relief valve 6, a relief valve 7, a tank 8, a flow diversion valve device 9, a regenerative motor 10 and a generator 11 as auxiliary equipment, a remote control valve 12, a pressure sensor 13 and a controller 14, and oil passages 16 to 34. Note that the regenerative motor 10 and generator 11 are shown as examples of auxiliary equipment, but this is not limited to them. 【0018】 The main hydraulic pump 2 is a constant-capacity pump connected to a drive mechanism 1 such as an internal combustion engine, and rotates using power from the drive mechanism 1 to supply pressurized oil downstream through the oil passage 23. 【0019】 The pressurized oil discharged from the main hydraulic pump 2 flows through the oil passage 23 and then through the flow diversion valve device 9 (described later) and the main flow passage 24-1 to the switching valve 4. The switching valve 4 is a 6-port, 3-position open-center type switching valve, and when the spool is in the neutral position, the entire amount of pressurized oil discharged from the main hydraulic pump 2 flows through the oil passage 16 to the tank 8. 【0020】 Furthermore, the main circuit, which includes the main hydraulic pump 2, is equipped with a relief valve 6 to prevent damage to the hydraulic equipment in the circuit when the rod 5a of the hydraulic cylinder 5 reaches its extended or retracted end, or when a sudden load is applied to the hydraulic cylinder 5, causing the oil in the circuit to become blocked and abnormally high pressure to build up. The high-pressure oil is discharged to the tank 8 through oil passages 17 and 18. 【0021】 Next, the pilot hydraulic pump 3, like the main hydraulic pump 2, is connected to the drive mechanism 1 and operates using power from the drive mechanism 1, supplying pressurized oil downstream through the oil passage 19. Here, a portion of the pressurized oil supplied downstream through the oil passage 19 is supplied to the remote control valve 12 through the oil passage 20. 【0022】 The remote control valve 12 is a variable pressure reducing valve. When the operating lever 12a operates the rod 5a of the hydraulic cylinder 5 in either the extension direction A or the retraction direction B, a pilot secondary pressure proportional to the operating lever stroke of the operating lever 12a is supplied to the signal port 4a or signal port 4b of the switching valve 4 through the pilot signal oil passage 21 or pilot signal oil passage 22, as shown in Figure 3, thereby controlling the extension position (extension amount) or retraction position (retraction amount) of the rod 5a. The amount of operation of the operating lever 12a is approximately equivalent to the stroke of the operating lever 12a and is called the operating lever stroke. In this invention, operation in the retraction direction B is referred to as a predetermined operation. 【0023】 When the operating lever 12a of the remote control valve 12 is operated in the extension direction A, and the switching valve 4 is switched to the extension position, pressurized oil from the main hydraulic pump 2 flows into the bottom chamber 5-1 of the hydraulic cylinder 5 through the oil passage 23, the flow divider device 9, the oil passage 24-1, the switching valve 4, and the oil passage 24-2. The oil in the rod chamber 5-2 then passes through the oil passage 25 and further through the switching valve 4 and the oil passage 26 to be discharged into the tank 8. As a result, the rod 5a of the hydraulic cylinder 5 operates in the extension direction. 【0024】 On the other hand, when the operating lever 12a of the remote control valve 12 is operated in the retraction direction B and the switching valve 4 is switched to the retraction position, pressurized oil from the main hydraulic pump 2 flows into the rod chamber 5-2 of the hydraulic cylinder 5 through the oil passage 23, the flow divider device 9, the oil passage 24-1, the switching valve 4, and the oil passage 25. The oil in the bottom chamber 5-1 then passes through the oil passage 24-2 and is further discharged to the tank 8 through the oil passage 26 via the switching valve 4. As a result, the rod 5a of the hydraulic cylinder 5 operates in the retraction direction. 【0025】 As shown in Figure 3, the remote control valve 12 outputs a pilot secondary pressure that increases proportionally with the increase in the operating lever stroke of the operating lever 12a of the remote control valve 12. The switching valve 4 is configured such that the spool stroke is approximately proportional to the pilot secondary pressure of the remote control valve 12. 【0026】 As shown in Figure 4, the opening characteristics are such that the PC (pump → cylinder) opening increases in accordance with the spool stroke, while the PT (pump → tank) opening decreases. As a result, the amount of pressurized oil supplied to the hydraulic cylinder 5 increases with the increase in the PC (pump → cylinder) opening, and as shown in Figure 5, the operating speed of the rod 5a of the hydraulic cylinder 5 increases. In other words, the rod speed can be controlled according to the operating lever stroke of the operating lever 12a of the remote control valve 12. 【0027】 Furthermore, when a load W acts on the hydraulic cylinder 5 in the direction of gravity as shown in Figure 2, the rod speed will be predominantly controlled by the CT opening (cylinder → tank) shown in Figure 4. A variable throttle As is provided in the flow path connecting oil passage 24-1 and oil passage 26 of the switching valve 4. This variable throttle As restricts the flow rate, thereby slowing down the operating speed of the rod 5a due to gravity W. 【0028】 Furthermore, in regions where the spool stroke X1 relative to the neutral position of the switching valve 4 is relatively small, i.e., where the PC (pump → cylinder) opening area Sc is small, the PT (pump → tank) opening area St decreases rapidly from the fully open state. Therefore, when the entire amount of pressurized oil from the main hydraulic pump 2 is supplied to the switching valve 4, heat is generated within the switching valve 4, and there is a risk that spool sticking, or so-called thermal shock, may occur due to localized thermal expansion of the spool bore and spool of the valve body. 【0029】 In this embodiment, when the spool stroke X1 of the switching valve 4 is relatively small, the flow diversion valve device 9 diverts a portion of the pressurized oil from the main hydraulic pump 2 to the oil passage 27, which serves as a branch flow path (see Figure 2). The configuration of the flow diversion valve device 9 will be described in detail later. 【0030】 Returning to Figure 2, the regenerative motor 10 is connected to the oil passage 27. The regenerative motor 10 is connected to the tank 8 via the oil passage 31 and also to the generator 11 via the connecting part 32. The generator 11 outputs power with the output characteristics shown in Figure 6 according to the rotational speed of the drive mechanism such as the regenerative motor 10. Furthermore, when the spool stroke X1 of the switching valve 4 is relatively large, if the amount of power generated by the generator 11 reaches the allowable storage capacity of the capacitor, the electrical signal from the controller 14 to the flow diversion valve 91 (described later) is cut off, which cuts off the inflow of pressurized oil to the regenerative motor 10, stopping the generator 11 and ceasing to generate power. 【0031】 Furthermore, an oil passage 29 branches off from the oil passage 27, and a relief valve 28 is connected via the branched oil passage 29. When abnormally high pressure occurs in the oil passage 27, the relief valve 28 activates, and the high-pressure oil is discharged to the tank 8 via the oil passage 30. 【0032】 Furthermore, the pilot circuit, which includes the pilot hydraulic pump 3, is equipped with a relief valve 7 to control the maximum pressure within the circuit. When the lever of the remote control valve 12 is in the neutral position, pressurized oil is discharged to the tank 8 through oil passages 33 and 34. 【0033】 Furthermore, a pressure sensor 13 is installed on the pilot signal oil passage 22, and when the operating lever 12a of the remote control valve 12 is operated in the contraction direction B, and a pilot secondary pressure is generated in the pilot signal oil passage 22, an electrical signal is input from the pressure sensor 13 to the controller 14. 【0034】 When an electrical signal is input to the controller 14, an electrical signal is output to the diversion valve 91 from the calculation circuit pre-built into the controller 14, and the diversion valve 91 switches to a position where it branches into oil passage 24-1 and oil passage 27. 【0035】 The controller 14 controls the switching valve 4 to switch the diversion valve 91 at the same time as the switching valve 4 if the storage capacity of the storage unit has not reached its allowable level. When the diversion valve 91 is switched, a portion of the pressurized oil flows through the diversion valve 91 and the oil passage 27 to the regenerative motor 10, causing the regenerative motor 10 to rotate and generating electricity with the generator 11. The oil that has passed through the regenerative motor 10 is discharged to the tank 8 via the oil passage 30. 【0036】 The flow diversion valve device 9 is a pressure-compensated electromagnetic proportional control flow control valve that can variably divert pressurized oil to the oil passage 27 side based on an electrical signal from the controller 14. In other words, the flow diversion valve device 9 adjusts the flow rate of pressurized oil diverted to the oil passage 27 side (hereinafter sometimes referred to as the priority flow rate). 【0037】 Furthermore, the flow diversion valve device 9 has flow control characteristics as shown in Figure 7. When no electrical signal is input from the controller 14 to the flow diversion valve 91, the priority flow rate to the oil passage 27 is zero, and the priority flow rate can be increased or decreased in proportion to the electrical signal from the controller 14. 【0038】 As shown in Figure 8, the flow diversion valve device 9 mainly consists of a flow diversion valve 91, a pressure compensation valve 92, and a housing 93 that accommodates them. Figure 8 shows the state of the flow diversion valve device 9 when the main hydraulic pump 2 is stopped and the flow diversion valve 91 is not energized. Furthermore, for the sake of convenience in the following explanation, the right side of Figure 8 may be referred to as one side and the left side as the other side. 【0039】 The flow diversion valve 91 is a 2-port, 2-position normally closed electromagnetic proportional throttle valve, and is also a spool-type valve. In the state shown in Figure 8, the spool valve body of the flow diversion valve 91 is biased to the other side, creating a neutral position. 【0040】 The pressure compensation valve 92 is a 4-port, 2-position pilot valve that operates based on the pilot pressure of oil passages 24-1 and 27, and is a spool-type valve. In the state shown in Figure 8, the spool valve body of the pressure compensation valve 92 is in a neutral position, biased to one side. 【0041】 The housing 93 is provided with a pump-side port 93a, a switching valve-side port 93b, a regenerative motor-side port 93c, flow paths 931-935, and pilot flow paths 938 and 939. The pump-side port 93a is connected to the oil passage 23. The switching valve-side port 93b is connected to the oil passage 24-1. The regenerative motor-side port 93c is connected to the oil passage 27. 【0042】 Flow path 931 extends from the pump-side port 93a to the flow diversion valve 91. Flow path 932 branches off from flow path 931 and extends to the pressure compensation valve 92. Flow path 933 extends to connect the flow diversion valve 91 and the pressure compensation valve 92. Flow path 934 extends from the pressure compensation valve 92 to the switching valve-side port 93b. Flow path 935 extends from the pressure compensation valve 92 to the regenerative motor-side port 93c. 【0043】 Flow paths 931, 932, and 934 function as first connecting passages that can connect oil passage 23 and oil passage 24-1 via pressure compensation valve 92. In addition, flow paths 931, 933, and 935 function as second connecting passages that can connect oil passage 23 and oil passage 27 via pressure compensation valve 92. 【0044】 The pilot channel 938 is connected from channel 932 to one end of the pressure compensation valve 92. The pilot channel 939 is connected from channel 933 to the other end of the pressure compensation valve 92. 【0045】 In the neutral position of the flow divider valve 91, the flow path 931 and the flow path 933 are not in communication. Also, in the neutral position of the pressure compensation valve 92, the flow path 932 and the flow path 934 are not in communication, while the flow path 933 and the flow path 935 are in communication in a fully open state. 【0046】 As shown in Figure 9, when the main hydraulic pump 2 operates from the state shown in Figure 8, pressurized oil from the main hydraulic pump 2 flows into the pilot passage 938 through the passage 932, and the pressure in the pilot passage 938 increases, causing the pressure compensation valve 92 to switch to the switching position. 【0047】 When the pressure compensation valve 92 is in the switching position, the passage 932 and the passage 934 are in full open communication (i.e., pressurized oil can pass through the first communication passage), and the passage 933 and the passage 935 are not in communication. Therefore, when the main hydraulic pump 2 is operating and the flow divider valve 91 is not energized, the entire amount of pressurized oil discharged from the main hydraulic pump 2 is supplied to the switching valve 4. 【0048】 Next, Figure 10 will be used to explain the state when the flow divider valve 91 is energized from the state shown in Figure 9. Figure 10 will explain a state in which there is almost no pressure difference between the pressure in oil passage 24-1 and the pressure in oil passage 27. Furthermore, Figures 10 to 12 will explain the control of the flow divider valve device 9 in a region where the spool stroke X1 of the switching valve 4 is relatively small, that is, in a region where the PC (pump → cylinder) opening area Sc is small. 【0049】 As shown in Figure 10, when the diversion valve 91 is energized from the state shown in Figure 9 and the diversion valve 91 is in the switching position, the flow path 931 and the flow path 933 are connected, and pressurized oil flows into the pilot flow path 939, balancing the pressure acting on the pressure compensation valve 92, which is then positioned between the neutral position and the switching position. 【0050】 When the pressure compensation valve 92 is positioned between the neutral position and the switching position, the flow path 932 and the flow path 934 become connected, and the flow path 933 and the flow path 935 become connected (i.e., pressurized oil can pass through the second connecting passage), so that the pressurized oil discharged from the main hydraulic pump 2 is divided between the switching valve 4 and the regenerative motor 10. 【0051】 Next, using Figure 11, we will explain the configuration in which the flow divider valve 91 is energized from the state shown in Figure 9 when the pressure in oil passage 27 is higher than the pressure in oil passage 24-1. 【0052】 As shown in Figure 11(a), when the pressure in oil passage 27 is higher than the pressure in oil passage 24-1, the pressure in pilot passage 938 is lower than the pressure in pilot passage 939. 【0053】 As a result, as shown in Figure 11(b), the spool of the pressure compensation valve 92 moves slightly to one side compared to the state in Figure 11(a), narrowing the opening connecting the flow path 932 and the flow path 934, while widening the opening connecting the flow path 933 and the flow path 935, thereby ensuring sufficient flow rate to the regenerative motor 10. 【0054】 Next, using Figure 12, we will explain the configuration in which the flow divider valve 91 is energized from the state shown in Figure 9 when the pressure in oil passage 27 is lower than the pressure in oil passage 24-1. 【0055】 As shown in Figure 12(a), when the pressure in oil passage 27 is lower than the pressure in oil passage 24-1, the pressure in pilot passage 938 is higher than the pressure in pilot passage 939. 【0056】 As a result, as shown in Figure 12(b), the spool of the pressure compensation valve 92 moves slightly to the other side compared to the state in Figure 12(a), narrowing the opening connecting the flow path 933 and the flow path 935, while widening the opening connecting the flow path 932 and the flow path 934, thereby ensuring the flow rate to the switching valve 4. 【0057】 As shown in Figure 13, in the region where the spool stroke X1 of the switching valve 4 is relatively small and the PC opening is narrow, most of the pump flow rate Q is controlled to flow to the priority circuit on the oil passage 27 side via the flow diversion valve device 9. Although not shown, as the PC opening widens, the priority flow rate to the oil passage 27 side is controlled to gradually decrease. This allows the regenerative motor 10 and generator 11 provided in the priority circuit to generate electricity, store it in the capacitor, and utilize it as electrical energy, while also preventing excessive heat generation within the switching valve 4. 【0058】 As explained above, the flow diversion valve device 9 is equipped with a pressure compensation valve 92 downstream of the flow diversion valve 91. The pressure compensation valve 92 variably adjusts the opening of oil passages 24-1 and 27 in accordance with the differential pressure between the oil passage 24-1 on the switching valve 4 side and the oil passage 27 on the regenerative motor 10 side, thereby compensating for the flow rate to oil passages 24-1 and 27. This prevents excessive oil supply to oil passage 24-1 or insufficient oil supply to oil passage 24-1 when the switching valve 4 is operating. 【0059】 Furthermore, since the pressure compensation valve 92 is a pilot valve that operates based on the pilot pressure of oil passages 24-1 and 27, there is no need to separately provide a means for detecting the differential pressure between oil passages 24-1 and 27. This simplifies the structure of the pressure compensation valve 92 and ensures reliable compensation of the flow rate to oil passage 27 and oil passage 24-1. 【0060】 Furthermore, since the flow divider valve 91 and the pressure compensation valve 92 are housed in the same housing 93, the flow divider valve 91 and the pressure compensation valve 92 can be made more compact. 【0061】 Furthermore, the housing 93 is provided with flow paths 932 and 934 that connect the oil passage 23 on the main hydraulic pump 2 side to the oil passage 24-1 via a pressure compensation valve 92, and flow paths 933 and 935 that can connect the oil passage 23 and the oil passage 27 via the pressure compensation valve 92. The flow diversion valve 91 is arranged to adjust the opening degree of flow path 933, thereby configuring the flow diversion valve device 9. With this configuration, since the flow diversion valve 91 is not provided in the flow path 932 from the main hydraulic pump 2 to the pressure compensation valve 92, pressurized oil can pass through to the oil passage 24-1 with minimal loss. 【0062】 Furthermore, since the oil passage 27 is equipped with a regenerative motor 10 that operates using the oil flowing through the oil passage 27, the regenerative motor 10 can be driven using the oil branched into the oil passage 27, and electricity can be generated by the generator 11. [Examples] 【0063】 Next, the fluid pressure circuit according to Example 2 will be described with reference to Figures 14 and 15. Note that descriptions of components identical to those in the previous example will be omitted. 【0064】 As shown in Figure 14, the hydraulic circuit of Embodiment 2 differs from Embodiment 1 in that the auxiliary device is an accumulator 200, and the configuration around the accumulator 200 is the same as that of Embodiment 1, but all other aspects are the same. 【0065】 An electromagnetic switching valve 201 is connected to the oil passage 27. The electromagnetic switching valve 201 is a 4-port, 2-position type electromagnetic switching valve, and is switched by an electrical signal input from the controller 14' via the signal line C2. 【0066】 Oil passages 35, 36, and 37 extend from the electromagnetic switching valve 201. Oil passage 35 communicates with the oil chamber 202a of the pressurizer 202, and oil passage 36 communicates with the oil chamber 202b on the rear side of the pressurizer 202. Oil passage 37 is connected to the tank 8. 【0067】 The pressure intensifier 202 consists of a piston 202B enclosed in a case 202A. The case 202A and piston 202B are made up of a large diameter section and a small diameter section, and the peripheral walls of the large diameter section and the peripheral walls of the small diameter section slide against each other. In this pressure intensifier 202, according to Pascal's theorem, the pressure in the oil chamber 202c on the front side is increased by the ratio of the cross-sectional areas of the load pressure in the oil chamber 202b on the rear side. 【0068】 When the solenoid of the electromagnetic switching valve 201 is demagnetized, the pressurized oil, which has been branched into the oil passage 27 by the flow diversion valve device 9, is introduced into the oil chamber 202a of the pressurizer 202 through the electromagnetic switching valve 201 and the oil passage 35, while the oil in the oil chamber 202b is led to the tank 8 through the oil passage 36, the electromagnetic switching valve 201, and the oil passage 37, and the piston 202B is positioned in the retracted end position. 【0069】 When the solenoid of the electromagnetic switching valve 201 is energized, pressurized oil flowing through the oil passage 27 is introduced into the oil chamber 202b through the electromagnetic switching valve 201 and the oil passage 36, and the oil in the oil chamber 202a is led to the tank 8 through the oil passage 35, the electromagnetic switching valve 201, and the oil passage 37, causing the piston 202B to move in the extension direction. As a result, the oil in the oil chamber 202c is accumulated in the accumulator 200 through the check valve 50 and the oil passage 38. 【0070】 Next, when the solenoid of the electromagnetic switching valve 201 is demagnetized, the spring of the electromagnetic switching valve 201 returns it to its original position, and the pressurized oil flowing through the oil passage 27 is introduced into the oil chamber 202a, and the oil in the oil chamber 202b is discharged into the tank 8, causing the piston 202B to move in the compression direction. As a result, the oil in the tank 8 is introduced into the oil chamber 202c through the oil passage 39 and the check valve 51. 【0071】 As described above, the reciprocating motion of the piston 202B, caused by repeatedly energizing and demagnetizing the solenoid of the electromagnetic switching valve 201, allows low-pressure oil to flow into the oil chamber 202c from the tank 8 via the oil passage 39 and the check valve 51, and then high-pressure oil is discharged into the oil passage 38 via the check valve 50, thereby accumulating high-pressure oil in the accumulator 200. 【0072】 Next, when the pressure in the accumulator 200 reaches a predetermined value, an electrical signal from the pressure sensor 53 is input to the controller 14, and from the controller 14, an electrical signal is input to the regenerative valve 203 via the signal line C3. 【0073】 The regenerative valve 203 is a 2-port, 2-position normally closed solenoid proportional valve, and is variably switched by an electrical signal input from the controller 14 via the signal line C3. When the regenerative valve 203 is switched, the high-pressure oil accumulated in the accumulator 200 is introduced into the oil passage 24-2 through the oil passage 40 branching from the oil passage 38, the regenerative valve 203, and the oil passage 41 extending from the regenerative valve 203. 【0074】 Furthermore, this circuit is equipped with a relief valve 54 to prevent damage to the oil pump in the circuit if the oil becomes blocked and causes abnormally high pressure. The high-pressure oil is discharged to the tank 8 through the oil passage 42, which branches off from the oil passage 38, the relief valve 54, and the oil passage 43. 【0075】 Furthermore, Figure 15 shows the opening characteristics of the switching valve 4 of this embodiment 2 during cylinder extension operation. Compared to the opening characteristics of the switching valve 4 of embodiment 1 shown in Figure 4, the PC opening characteristics and CT opening characteristics of the switching valve 4 of this embodiment 2 are the same, but the PT opening characteristics are different, and the opening area is smaller than that of the PT opening in Figure 4. 【0076】 Furthermore, in this embodiment 2, the PT opening is smaller than that of embodiment 1 in Figure 4. This is because, as described above, in the region where the spool stroke of the switching valve 4 is relatively small and the PC opening is small, most of the excess oil is flowed to the priority circuit via the flow divider valve device 9, and the amount of oil supplied from the main hydraulic pump 2 to the switching valve 4 is reduced. Therefore, the PT opening is made smaller to ensure that oil flows to the hydraulic cylinder 5 via the PC opening. 【0077】 Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included. 【0078】 For example, although the flow diversion valves in Embodiments 1 and 2 were described as electromagnetic proportional control valves switched by a solenoid, the flow diversion valve may also be a pilot-operated type that operates using pilot pressure supplied from an external source. Furthermore, the flow diversion valve may control a constant flow rate by switching an external signal on or off. 【0079】 Furthermore, although the pressure compensation valves in Examples 1 and 2 were described as pilot valves that operate according to the pilot pressure between the main flow path and the branch flow path, the pressure compensation valve may also be an electromagnetic proportional control valve that is switched by a solenoid, for example. 【0080】 Furthermore, although the pressure compensation valves in Examples 1 and 2 were exemplified as adjusting the opening degree on the main flow path side and the opening degree on the branch flow path side, they may also be configured to adjust only the opening degree on the branch flow path side. 【0081】 Furthermore, although the flow diversion valve devices in Examples 1 and 2 were illustrated as having an integrated housing for the flow diversion valve and the housing for the pressure compensation valve, they may also be composed of separate housings. 【0082】 Furthermore, although the flow diversion valve devices in Examples 1 and 2 above were illustrated in which the pressure compensation valve is provided downstream of the flow diversion valve, the pressure compensation valve may also be located upstream of the flow diversion valve. 【0083】 Furthermore, while Embodiment 1 illustrates a configuration in which excess oil diverted to a branched flow path by a flow diversion valve device is stored in a capacitor using a regenerative motor and generator and utilized as electrical energy, and Embodiment 2 illustrates a configuration in which high-pressure oil is flowed to a cylinder using an electromagnetic switching valve, a pressure booster, an accumulator, and a regenerative valve to regenerate energy, it goes without saying that excess oil may be utilized by any means other than those described above using a flow diversion valve device. [Explanation of symbols] 【0084】 1. Drive mechanism 2. Main hydraulic pump (fluid supply source) 3. Pilot hydraulic pump 4. Switching valve 5. Hydraulic cylinder (actuator device) 8 tanks 9. Flow Divider Valve Device 10 Regenerative motor (auxiliary equipment) 11. Generator (auxiliary equipment) 12 Remote control valve 13. Pressure Sensor 14,14' Controller 24-1 Oil passage (main passage) 24-2,25 Oil path (flow path) 27 Oil passage (branch channel) 91 Diverter valve 92 Pressure Compensation Valve 93 Housing 130 Hydraulic circuits (fluid pressure circuits) 200 Accumulator (Auxiliary Equipment) 201 Solenoid directional control valve 202 Pressure Booster (Auxiliary Equipment) 203rd Life Valve 932,934 Channel (First Linkage) 933,935 Channel (First connecting passage)

Claims

[Claim 1] A fluid supply source, An actuator device which operates in an extension or contraction direction when fluid from the fluid supply source is supplied to the bottom chamber or rod chamber, A fluid pressure circuit comprising a spool-type switching valve provided in the flow path between the fluid supply source and the actuator device for switching the flow path, The system further includes a flow divider valve capable of diverting at least a portion of the fluid flowing from the fluid supply source to the main flow path on the switching valve side to a branch flow path where an auxiliary device is located. The aforementioned flow divider valve is equipped with a pressure compensation valve that variably adjusts the opening degree of the branch passage according to the differential pressure between the main passage and the branch passage, thereby compensating for the flow rate to the branch passage. A fluid pressure circuit in which, in a region where the spool stroke of the switching valve is small and the opening from the fluid supply source to the actuator device is narrow, a larger flow rate flows from the fluid supply source to the diversion valve than in a region where the spool stroke is large and the opening from the fluid supply source to the actuator device is wide. [Claim 2] The fluid pressure circuit according to claim 1, wherein the pressure compensation valve is a pilot valve that operates by the pilot pressure of the main flow path and the branch flow path. [Claim 3] The fluid pressure circuit according to claim 1, wherein the housing of the flow divider valve and the housing of the pressure compensation valve are integrated. [Claim 4] The fluid pressure circuit according to claim 1, wherein the flow divider valve comprises a housing having a first communication passage that connects the fluid supply source side flow path and the main flow path via the pressure compensation valve, and a second communication passage that connects the fluid supply source side flow path and the branch flow path via the pressure compensation valve, and a valve body that adjusts the opening degree of the second communication passage. [Claim 5] The fluid pressure circuit according to any one of claims 1 to 4, wherein the branch channel is provided with an auxiliary device that is operated by the fluid flowing in the branch channel.

Images