Fluid pressure circuit

Abstract

Provided is a fluid pressure circuit that can save energy.　A fluid pressure circuit 130 comprises a fluid supply source 2 and a cylinder device 5, and has: a valve 91 that causes a portion of a return fluid from the cylinder device 5 to branch off, and discharges the same through a diaphragm 9-4; and a regeneration passage R1 that causes the return fluid from one side 5-1 of the cylinder device 5 to circulate to the other side 5-2 of the cylinder device 5 between the fluid supply source 2 and the cylinder device 5.

Description

【Technical Field】 【0001】 The present invention relates to a hydraulic circuit used for controlling the operation of a hydraulic circuit, for example, a cylinder device. 【Background Art】 【0002】 A hydraulic circuit is used to control the operation of a cylinder device in automobiles, construction machines, cargo handling and transportation vehicles, industrial machines, etc. 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 the hydraulic circuit, thereby driving a load. In such a hydraulic circuit, energy saving is required, and some of the fluid discharged from the cylinder device is regenerated by a regeneration motor to effectively utilize energy. 【0003】 As such a hydraulic circuit, for example, there is one like Patent Document 1. The hydraulic circuit of Patent Document 1 mainly includes a pump, a cylinder device, a regeneration motor, a switching valve connected between the pump and the cylinder device, and a flow dividing valve capable of diverting the fluid discharged from the cylinder device to the regeneration motor. The switching valve can change the spool to the extended position, neutral position, and retracted position. The flow dividing valve is configured such that the spool is changed from the neutral position to the flow dividing position. 【0004】 Thereby, when the switching valve is switched to the extended position, the pressure oil from the hydraulic pump is introduced into the bottom chamber of the cylinder device, and the rod extends from the cylinder. On the other hand, when the switching valve is switched to the retracted position, the pressure oil from the hydraulic pump is introduced into the rod chamber of the cylinder device, and the rod retracts into the cylinder. 【Prior Art Documents】 【Patent Documents】 【0005】 【Patent Document 1】 International Publication No. 2018 / 147261 (page 7, Figure 2) 【Summary of the Invention】 [Problems that the invention aims to solve] 【0006】 In a fluid pressure circuit like the one described in Patent Document 1, when the rod retracts, the spool of the flow divider valve is moved from the neutral position to the flow divider position, and a portion of the return oil discharged from the bottom chamber is supplied to the regenerative motor, which drives the generator to obtain electrical energy. 【0007】 Incidentally, in recent years in particular, awareness of energy conservation has been increasing from the perspective of SDGs, carbon neutrality, etc. Therefore, it is desirable to use a regenerative drive device, such as a generator that uses the fluid discharged as a power source due to the expansion and contraction of the cylinder device, in combination with a regeneration passage that reuses the fluid discharged as a fluid supplied to the cylinder device. However, when attempting to use a regenerative drive device and a regeneration passage together, it has been difficult to stably operate regeneration and regeneration together, for example, because sufficient fluid pressure can not be obtained to allow the fluid to pass through the regeneration passage and flow into the supply-side flow path. 【0008】 This invention was made in view of these problems, and aims to provide an energy-saving fluid pressure circuit. [Means for solving the problem] 【0009】 To solve the above problems, the fluid pressure circuit of the present invention is A fluid pressure circuit comprising a fluid supply source and a cylinder device, The device has a valve that branches off a portion of the return fluid from the cylinder device and discharges it through a throttle, and a regeneration passage between the fluid supply source and the cylinder device that allows the return fluid from one side of the cylinder device to flow to the other side of the cylinder device. According to this design, some of the return fluid from the cylinder device is discharged through the throttle, which stabilizes the fluid pressure on the primary side of the cylinder device. This allows fluid at the appropriate pressure to flow into the regeneration passage. As a result, an energy-saving circuit can be created. 【0010】 The fluid pressure circuit further includes a passage having less fluid resistance than the passage through the throttle in the valve, and the passage with less fluid resistance may be able to communicate with the regeneration passage. This method can prevent a decrease in the operating speed of the cylinder device and improve regeneration efficiency. 【0011】 The passage with low fluid resistance may be provided in the valve. This allows for a simplification of the fluid pressure circuit. 【0012】 Two passages are provided through the aforementioned diaphragm, and one of them may be able to communicate with the regeneration passage. This allows for preferentially guiding the fluid to passages with less fluid resistance. Furthermore, it can more effectively prevent a decrease in the operating speed of the cylinder device. 【0013】 The device has a switching valve provided in the flow path between the fluid supply source and the valve, which controls the inflow and outflow of fluid between the fluid supply source and the cylinder device, and the regeneration passage may be located within the switching valve. This allows for synchronized position control of the valve and the switching valve, and ensures that the fluid used for regeneration is efficiently supplied to the cylinder device. 【0014】 The regeneration passage may be accessible only when the cylinder device is being retracted. According to this, by utilizing gravity acting on the cylinder device, it is possible to more reliably ensure that the pressure of the primary side fluid on the cylinder device side is higher than the pressure of the fluid pumped from the fluid supply source. [Brief explanation of the drawing] 【0015】 [Figure 1] This figure shows a wheel loader incorporating a hydraulic circuit according to Embodiment 1 of the present invention. [Figure 2]It is a diagram showing the hydraulic circuit in Example 1. [Figure 3] It is a graph showing the relationship between the operation lever stroke and the pilot secondary pressure. [Figure 4] It is a graph showing the relationship between the spool stroke and the opening area when the switching valve contracts. [Figure 5] It is a graph showing the relationship between the operation lever stroke and the retraction speed of the rod in the cylinder device. [Figure 6] It is a graph showing the relationship between the electrical signal from the controller and the priority flow rate in the flow dividing valve. [Figure 7] It is a graph showing the relationship between the rotational speed and the output power in the regeneration mechanism. [Figure 8] It is an enlarged view of the main part showing the flow dividing valve device and the switching valve in the neutral position in Example 1. [Figure 9] It is an enlarged view of the main part showing the flow dividing valve device and the switching valve in the operating position in Example 1. [Figure 10] It is a diagram showing the hydraulic circuit in Example 2 of the present invention. [Figure 11] It is a graph showing the relationship between the electrical signal from the controller and the opening area in the regeneration valve. [Figure 12] It is an enlarged view of the main part showing the flow dividing valve device, the regeneration valve and the switching valve in the neutral position in Example 2. [Figure 13] It is an enlarged view of the main part showing the flow dividing valve device, the regeneration valve and the switching valve in the operating position in Example 2. [Figure 14] It is a diagram showing the hydraulic circuit in Example 3 of the present invention. [Figure 15] It is a perspective view, a plan view and a side view showing the switching valve and the flow dividing valve device in Example 3. [Figure 16] It is an enlarged view of the main part showing the flow dividing valve device and the switching valve in the neutral position in Example 3. <000偶爾0103>It is an enlarged view of the main part showing the flow dividing valve device and the switching valve in the operating position in Example 3. <00001偶爾4> [Figure 18]This graph shows a comparison of the rod's retraction speed relative to the operating lever stroke during a current split. [Figure 19] This figure shows other flow dividers that can be used as flow dividers in Example 3. [Figure 20] This graph shows the relationship between the electrical signal from the controller and the preferred flow rate in yet another flow divider valve applicable as the flow divider valve in Example 3. [Figure 21] This figure shows a hydraulic circuit in Embodiment 4 of the present invention. [Modes for carrying out the invention] 【0016】 Embodiments for implementing the fluid pressure circuit according to the present invention will be described below based on examples. [Examples] 【0017】 A fluid pressure circuit according to Embodiment 1 of the present invention will be described with reference to Figures 1 to 9. 【0018】 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 a work machine, construction machine, material handling vehicle, automobile, 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 driving, a working 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 driving, a hydraulic cylinder 104, and a hydraulic circuit 130 for work that drives the hydraulic cylinder 5, etc., as a cylinder device. 【0019】 As shown in Figure 2, the hydraulic circuit 130 consists of a main hydraulic pump 2 as a fluid supply means 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 a regenerative mechanism, a remote control valve 12, a pressure sensor 13, a controller 14, and oil passages 16 to 31. Although a regenerative motor is given as an example of a regenerative drive source, it is not limited to this. 【0020】 The main hydraulic pump 2 is connected to a drive mechanism 1 such as an internal combustion engine, and is driven by power from the drive mechanism 1 to supply pressurized oil downstream through the oil passage 23. 【0021】 The pressurized oil discharged from the main hydraulic pump 2 flows through the oil passage 23 into 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 into the tank 8. 【0022】 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 due to abnormally high pressure of the oil 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, and the high-pressure oil is discharged to the tank 8 through oil passages 17 and 18. 【0023】 Next, the pilot hydraulic pump 3, like the main hydraulic pump 2, is connected to the drive mechanism 1 and is driven by the 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. 【0024】 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. 【0025】 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, oil passage 24-1, flow divider valve device 9, and oil passage 24-2, and the oil in the rod chamber 5-2 passes through the oil passage 25 and then through the switching valve 4 and oil passage 26 to be discharged to the tank 8. As a result, the rod 5a of the hydraulic cylinder 5 operates in the extension direction. 【0026】 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 passages 23 and 25, and the oil in the bottom chamber 5-1 passes through the oil passage 24-2, the flow divider valve device 9 and the oil passage 24-1, and is then 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. 【0027】 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 so that its spool stroke is approximately proportional to the pilot secondary pressure of the remote control valve 12, and as shown in Figure 4, it has an opening characteristic in which its opening amount increases according to the spool stroke. As the opening amount increases, the amount of pressurized oil supplied to the hydraulic cylinder 5 increases, 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. 【0028】 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 6. 【0029】 Returning to Figure 2, the switching valve 4 has an oil passage 4-1, a throttle 4-2, an oil passage 4-3, a check valve 4-4, and an oil passage 4-5 on its retracted position side. In the retracted position, oil passage 4-1 is connected to oil passages 24-1 and 26 (see Figure 9). A throttle 4-2 is provided in oil passage 4-1. Oil passage 4-3 is branched to oil passage 4-1 and also to oil passage 4-5 on the hydraulic cylinder 5 side of the throttle 4-2. A check valve 4-4 is provided in oil passage 4-3. Oil passage 4-5 is connected to oil passages 23 and 25 (see Figure 9). 【0030】 In oil passage 4-1, the flow rate of return oil discharged from the bottom chamber 5-1 of the hydraulic cylinder 5 and flowing toward the tank 8 is restricted by the throttle 4-2. As a result, the pressure of the return oil discharged from the bottom chamber 5-1 is more easily maintained in the region of oil passage 4-1 on the hydraulic cylinder 5 side of the throttle 4-2. 【0031】 The return oil discharged from the bottom chamber 5-1 is pressurized by the load W acting in the direction of gravity, in addition to the fluid pressure of the oil that flows into the rod chamber 5-2, so it tends to be higher than the fluid pressure of the oil that is pumped by the main hydraulic pump 2 and flows through the oil passage 4-5. 【0032】 Therefore, as shown in Figure 9, when the fluid pressure in the region of oil passage 4-1 on the hydraulic cylinder 5 side of the throttle 4-2 exceeds the fluid pressure in oil passage 4-5, the check valve 4-4 opens. 【0033】 As a result, the oil discharged from the bottom chamber 5-1 of the hydraulic cylinder 5 flows into oil passage 4-5 through oil passages 4-1, 4-3 and check valve 4-4, as indicated by the white arrows in Figure 9, and is supplied to the rod chamber 5-2 together with the oil pumped by the main hydraulic pump 2. Note that the white arrows in Figure 9 are for indicating the flow direction of regeneration, and pressure and flow rate are not reflected. The same applies to Figures 13 and 17. 【0034】 In this way, the high-pressure oil discharged from the bottom chamber 5-1 of the hydraulic cylinder 5 can be reused to operate the rod 5a of the hydraulic cylinder 5 in the retraction direction, thereby reducing the load on the main hydraulic pump 2 and achieving energy savings. Here, the oil passage 4-3 and the check valve 4-4 are the regeneration passage R1 in this invention. 【0035】 As shown in Figure 2, the pilot circuit equipped with the pilot hydraulic pump 3 has a relief valve 7 installed to control the maximum pressure in the circuit, and 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 27 and 28. 【0036】 A flow divider valve device 9 is provided between the oil passages 24-1 and 24-2 that connect the bottom chamber 5-1 of the hydraulic cylinder 5 to the switching valve 4. 【0037】 The flow diversion valve device 9 mainly comprises a flow diversion valve 91, which is a 3-port, 2-position normally open electromagnetic proportional throttle valve; a relief valve 92, which controls the maximum pressure in the circuit of the flow diversion valve device 9; and a housing 93 that houses these components. 【0038】 As shown in Figures 8 and 9, the housing 93 is provided with ports 93a to 93d, an opening 93e, and oil passages 94 to 98. 【0039】 Port 93a is connected to oil passage 24-2. Port 93b is connected to oil passage 24-1. Port 93c is connected to oil passage 29 extending from the regenerative motor 10. Port 93d is connected to oil passage 30 which is connected to tank 8. An electrical signal wire connecting the controller 14 and the flow divider valve 91 is inserted through the through-hole opening 93e. 【0040】 Oil passage 94 connects port 93a to flow divider valve 91. Oil passage 95 connects flow divider valve 91 to port 93b. Oil passage 96 connects flow divider valve 91 to port 93c. Oil passage 97 connects oil passage 96 to relief valve 92. Oil passage 98 connects relief valve 92 to port 93d. 【0041】 The flow diversion valve 91 is a pressure-compensated electromagnetic proportional control flow control valve that can variably divert a flow rate (hereinafter sometimes referred to as the priority flow rate) to the oil passage 9-3 side, which will be described later, based on an electrical signal from the controller 14. 【0042】 Furthermore, the flow divider valve 91 has flow control characteristics as shown in Figure 6. When no electrical signal is input from the controller 14, the priority flow rate to the oil passage 9-3 is zero, and the priority flow rate can be increased or decreased in proportion to the electrical signal from the controller 14. 【0043】 The flow divider valve 91 includes an oil passage 9-1, a throttle 9-2, an oil passage 9-3, a throttle 9-4, and an oil passage 9-5. In oil passage 9-1, throttle 9-2 is provided on the side of the switching valve 4 where oil passage 9-3 is branched off. Oil passage 9-3 is branched off from oil passage 9-1 and is also connected to oil passage 29. A throttle 9-4 is provided in oil passage 9-3. 【0044】 Oil passage 9-1 is connected to oil passages 24-1 and 24-2 as a function of the position when the flow divider valve 91 switches from the neutral position, i.e., the regenerative position. Oil passage 9-5 is connected to oil passages 24-1 and 24-2 as a function of the neutral position, i.e., the non-regenerative position. 【0045】 Furthermore, the flow divider valve device 9 is equipped with a relief valve 92 between oil passages 97 and 98 to prevent the oil in the oil passages from becoming abnormally high pressure and damaging the oil pump within the flow divider valve device 9. This allows high-pressure oil to be discharged to the tank 8 through oil passages 97, 98 and oil passage 30. 【0046】 The generator 11 is connected to the regenerative motor 10 by a coupling section 32, and outputs power with the output characteristics shown in Figure 7 according to the rotational speed of the drive mechanism such as the regenerative motor 10. Furthermore, when the amount of power generated by the generator 11 reaches the allowable storage capacity of the battery, the electrical signal from the controller 14 to the diversion valve 91 is cut off, and the diversion valve 91 returns to the neutral position, thereby cutting off the flow to the regenerative motor 10, stopping the generator 11 and ceasing to generate power. 【0047】 Next, we will explain the regeneration and regeneration processes using the return oil in the hydraulic circuit 130. 【0048】 As shown in Figure 2, a pressure sensor 13 is installed on the pilot signal oil passage 22. 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. 【0049】 If an electrical signal is input to the controller 14 and the capacitor (not shown) has reached its allowable charge capacity, the calculation circuit pre-installed in the controller 14 does not output an electrical signal to the shunt valve 91. As a result, the shunt valve 91 remains in the non-regenerative position. 【0050】 As a result, when the flow divider valve 91 is in the non-regenerative position, the entire amount of return oil discharged from the bottom chamber 5-1 of the hydraulic cylinder 5 passes through oil passage 24-2, oil passage 94, oil passage 9-5 of the flow divider valve 91, oil passage 95, oil passage 24-1, and then flows into oil passage 4-1 of the switching valve 4. 【0051】 Furthermore, if the fluid pressure Pr of the return oil on the oil passage 4-1 side of the check valve 4-4 of the switching valve 4 is higher than the fluid pressure Pf of the supply oil pumped from the main hydraulic pump 2 on the oil passage 4-5 side of the check valve 4-4 (Pr > Pf), then the check valve 4-4 opens, and the return oil is reused as supply oil, as shown by the white arrow in Figure 9. In addition, a portion of the return oil that flows into oil passage 4-1 passes through throttle 4-2 and oil passage 26 and is discharged to tank 8. 【0052】 On the other hand, if an electrical signal is input to the controller 14 and the capacitor has not reached its allowable storage capacity, an electrical signal is output from the calculation circuit in the controller 14 to the diversion valve 91. As a result, the diversion valve 91 switches to the regenerative position. In connection with this, the controller 14 controls the diversion valve 91 to switch at the same time as the switching valve 4 switches. 【0053】 When the flow divider valve 91 switches from the neutral position to the regenerative position, it restricts the flow rate of the return oil that has flowed into the oil passage 9-3 by the throttle 9-4 and directs it into the oil passage 29. At this time, the flow rate is restricted by the throttle 9-4, or in other words, the flow of the return oil is obstructed, allowing the remaining return oil to pass through the oil passage 9-1 while maintaining a suitable primary pressure. 【0054】 Furthermore, since a throttle 9-2 is also provided in oil passage 9-1, a portion of the return oil can be directed to oil passage 9-3. In other words, the flow divider valve 91 can reliably branch off the return oil to oil passages 24-1 and 29. 【0055】 Therefore, the hydraulic circuit 130 is configured such that a portion of the return oil flows into the regenerative motor 10 through the oil passage 29 via the flow divider valve 91, causing the regenerative motor 10 to rotate and generating electricity with the generator 11. The return oil that has passed through the regenerative motor 10 is discharged into the tank 8 via the oil passage 31. 【0056】 Furthermore, the openings of throttle 9-2 and throttle 9-4 are adjusted so that the fluid pressure of the return oil flowing into oil passage 24-1 is higher than the fluid pressure of the oil pumped from the main hydraulic pump 2. 【0057】 As a result, even when the diversion valve 91 is in the regenerative position, the check valve 4-4 opens according to the differential pressure ΔP between the fluid pressure Pr of the return oil on the oil passage 4-1 side of the check valve 4-4 of the switching valve 4 and the fluid pressure Pf of the supply oil on the oil passage 4-5 side of the check valve 4-4. Therefore, as shown by the white arrow in Figure 9, the return oil can be reused as supply oil. 【0058】 As explained above, in this embodiment, the hydraulic circuit 130 allows a portion of the return oil from the hydraulic cylinder 5 to drive the regenerative motor 10 via the throttle 9-4 in the flow divider valve 91, and then be discharged to the tank 8. Therefore, the pressure of the primary side oil on the hydraulic cylinder 5 side, i.e., the oil passing through oil passages 24-2, 9-1, and 24-1, can be stabilized. This allows oil at the appropriate pressure to flow into oil passage 4-3 and check valve 4-4. As a result, an energy-saving circuit can be achieved. 【0059】 Furthermore, the switching valve 4 is located near the flow diversion valve 91, in other words, only accessible via oil passage 24-1. Therefore, by synchronizing the timing of switching the flow diversion valve 91 from the non-regenerative position to the regenerative position with the timing of switching the switching valve 4 from the neutral position to the retracted position, return oil can be smoothly supplied from oil passage 24-2 to oil passage 9-1 of the flow diversion valve 91, oil passage 24-1, and oil passage 4-1 of the switching valve 4, and also to oil passage 9-3 and oil passage 29 of the flow diversion valve 91. In this way, when branching the return oil flowing through oil passage 24-2, it is easy to control the timing of switching the flow diversion valve 91 and the timing of switching the switching valve 4. 【0060】 In addition, the regeneration passage R1 in this embodiment is provided in the switching valve 4, and a portion of the return oil that flows into the oil passage 4-1 flows directly into the oil passage 4-3. This reduces the influence of flow resistance and other factors acting on the return oil compared to the case where the regeneration passage is provided separately from the switching valve (for example, the case described in Embodiment 2 below). Therefore, the return oil used for regeneration is efficiently supplied to the hydraulic cylinder 5. Furthermore, compared to the case where the switching valve, flow divider valve, and regeneration passage are synchronized individually, the synchronization control is easier. 【0061】 Furthermore, since the regeneration passage R1 in this embodiment is provided on the retracted side of the switching valve 4, the pressure of the primary fluid on the hydraulic cylinder 5 side can be more reliably secured by utilizing gravity acting on the hydraulic cylinder 5. 【0062】 Although the flow divider valve 91 has been described as having throttles 9-2 and 9-4 in the oil passages 9-1 and 9-3, it is not limited to this configuration, and a throttle may not be provided in oil passage 9-1. Even with such a configuration, priority flow through oil passage 9-3 and throttle 9-4 can be ensured by the throttle 4-2 and check valve 4-4 in the switching valve 4. [Examples] 【0063】 Next, the fluid pressure circuit according to Example 2 will be described with reference to Figures 10 and 13. Note that descriptions of components identical to those in Example 1 and therefore redundant will be omitted. 【0064】 As shown in Figure 11, the hydraulic circuit 230 in this embodiment 2 differs from embodiment 1 in that the switching valve 204 does not have a regeneration passage, and a regeneration valve 40 is provided between the switching valve 204 and the flow diversion valve device 9, but all other aspects are the same. 【0065】 As shown in Figures 12 and 13, the regeneration valve 40 is a 4-port, 2-position electromagnetic proportional valve, and is a flow control valve that can variably control the flow rate by an electrical signal from the controller 14. The regeneration valve 40 is equipped with oil passages 40-1, 40-2, check valve 40-3, and 40-4 on the side of the regeneration position that can supply return oil to oil passage 25-2. Oil passage 40-1 is connected to oil passages 24-1a and 24-1b. Oil passage 40-2 is branched and connected to oil passages 40-1 and 40-4. Check valve 40-3 is provided in oil passage 40-2. Oil passage 40-4 is connected to oil passages 25-1 and 25-2. 【0066】 The regeneration valve 40 is configured such that its spool stroke is approximately proportional to the electrical signal from the controller 14, and as shown in Figure 11, it has an opening characteristic in which its opening amount increases according to the spool stroke. 【0067】 In the neutral position of the regeneration valve 40, the regeneration valve 40 connects oil passage 24-1a and oil passage 24-1b, and oil passage 25-1 and oil passage 25-2. On the other hand, the regeneration passage is omitted. 【0068】 When the operating lever 12a of the remote control valve 12 is operated in the contraction direction B, the regeneration valve 40, like the diversion valve 91, receives an electrical signal from the controller 14 according to the charge status of the capacitor (not shown). 【0069】 Then, in accordance with the pressure difference ΔP between the fluid pressure Pr of the return oil on the oil passage 40-1 side of the check valve 40-3 of the regeneration valve 40 and the fluid pressure Pf of the supply oil on the oil passage 40-4 side of the check valve 40-3, the check valve 40-3 is opened, and as shown by the white arrow in Figure 13, the return oil can be reused as supply oil. Here, the oil passage 40-2 and the check valve 40-3 constitute the regeneration passage R2 in this embodiment. Thus, the regeneration passage may be provided in addition to the switching valve. [Examples] 【0070】 Next, the fluid pressure circuit according to Example 3 will be described with reference to Figures 14 to 20. Note that the description of components that are the same as those in Examples 1 and 2 and therefore overlap will be omitted. 【0071】 As shown in Figures 14 and 15, the hydraulic circuit 330 in this embodiment 3 has a switching valve 304 (see Figure 14), which is a 3-position, 7-port open center-type switching valve, and a flow diversion valve device 309 (see Figure 14), which is a 4-port, 2-position normally open electromagnetic proportional throttle valve. The housing of the switching valve 304 and the housing 393 of the flow diversion valve device 309 are fixed in contact with each other by four bolts (see Figure 15). In embodiment 1, the housing of the switching valve 4 and the housing 93 of the flow diversion valve device 9 may also be fixed in contact with each other. The same applies to embodiment 2. 【0072】 As shown in Figure 14, the switching valve 304 mainly comprises an oil passage 4-1, a throttle 4-2, an oil passage 304-3, a check valve 304-4, an oil passage 4-5, and an oil passage 304-6 on its retracted position side. Oil passage 304-3 is branched and connected to the hydraulic cylinder 5 side of the throttle 4-2 in oil passage 4-1, and is also branched and connected to oil passage 304-6. A check valve 304-4 is provided in oil passage 304-6. Oil passage 304-6 is branched and connected to oil passage 4-5, and is also connected to oil passage 399 in the flow divider valve device 309 (see Figure 17). 【0073】 The flow diversion valve device 309 mainly comprises a flow diversion valve 391, a relief valve 92, and a housing 393 that accommodates them. 【0074】 As shown in Figures 16 and 17, the housing 393 is provided with ports 93a, 93c, 93d, 393b, and 393f, an opening 93e, and oil passages 94, 96-98, 395, and 399. 【0075】 Port 393b is directly connected to the port of the switching valve 304 to which oil passage 4-1 is switched. Port 393f is directly connected to the port of the switching valve 304 to which oil passage 304-6 is switched. 【0076】 Oil passage 395 connects the flow divider valve 391 to port 393b. Oil passage 399 connects the flow divider valve 391 to port 393f. 【0077】 The flow divider valve 391 includes oil passage 9-1, throttle 9-2, oil passage 9-3, throttle 9-4, oil passage 9-5, and oil passage 9-6. In oil passage 9-1, throttle 9-2 is provided on the side of the switching valve 4 where oil passage 9-3 is branched off. Oil passage 9-3 is branched off from oil passage 9-1 and also connected to oil passage 29. Oil passage 9-3 is provided with throttle 9-4. Oil passage 9-6 is branched off from oil passage 9-1 and also connected to oil passage 399 (see Figure 17). Furthermore, oil passage 9-6 is a passage with less fluid resistance than oil passage 9-3 and differs from oil passages 9-1 and 9-3 in that it does not have a throttle. 【0078】 As a result, when the flow divider valve 391 is in the regenerative position, a portion of the return oil that flows into the flow divider valve 391 from the oil passage 24-2 is preferentially guided to oil passages 9-6 and 9-9 rather than passing through throttle 9-2 and then through oil passages 4-1 and 9-4 in the switching valve 304 to flow into oil passage 29. Here, oil passages 9-6 and 9-9 are passages with low fluid resistance in this embodiment. 【0079】 Then, if the fluid pressure Pr of the return oil flowing from oil passage 9-6 into oil passage 304-6 in the switching valve 304 is higher than the fluid pressure Pf of the outgoing oil flowing into oil passage 4-5, the check valve 304-4 is opened. As a result, as shown by the white arrow in Figure 17, the return oil flows into oil passage 4-5 and is supplied to the rod chamber 5-2 in the hydraulic cylinder 5. 【0080】 Furthermore, a portion of the return oil that flows into the diversion valve 391, passes through the throttle 9-2, and flows into the oil passage 4-1 in the switching valve 304 flows into the oil passage 304-6 via the oil passage 304-3 (note that this flow rate is small, so no white arrow is shown in Figure 17). When the check valve 304-4 is opened, it flows into the oil passage 4-5 and is supplied to the rod chamber 5-2 in the hydraulic cylinder 5. Here, the oil passage 304-3, the check valve 304-4, and the oil passage 304-6 constitute the regeneration passage R3 in this embodiment. 【0081】 As a result, the hydraulic circuit 330 in this embodiment, shown by the solid line in the graph of Figure 18, can increase the operating speed of the hydraulic cylinder 5 compared to the hydraulic circuits 130 and 230 in embodiments 1 and 2, shown by the dotted lines. In other words, it is possible to prevent a decrease in the operating speed of the hydraulic cylinder 5 compared to when the flow divider is in the non-flow dividing position. 【0082】 Furthermore, in this embodiment, since the hydraulic circuit 330 regenerates pressurized oil through the oil passage 9-6, which has low fluid resistance, the return oil discharged from the hydraulic cylinder 5 can be preferentially used for regeneration compared to the hydraulic circuits 130 and 230 in embodiments 1 and 2, thus improving regeneration efficiency. 【0083】 Furthermore, since the flow diversion valve device 309 is integrally assembled with the switching valve 304, the flow resistance acting on the return fluid as it passes through the flow diversion valve device 309 and the switching valve 304 can be reduced. In addition, when assembling the switching valve 304 and the flow diversion valve device 309 into the hydraulic circuit 330, only oil passages 23, 24-2, 25, and 29 are required to connect to the switching valve 304 and the flow diversion valve device 309, resulting in good workability. 【0084】 Furthermore, since the oil passage 9-6, which has low fluid resistance, is provided in the flow divider valve 91, the fluid pressure circuit can be configured more simply compared to a configuration where, for example, another passage branched off from the passage communicating with the flow divider valve is a passage with low fluid resistance. 【0085】 Although the configuration described assumes that the flow divider valve device 309 is fixed to the switching valve 304 with four bolts, the configuration is not limited to this, and the number of bolts may be changed as appropriate. Furthermore, the devices may be fixed by means other than bolts, such as welding or adhesive. In addition, the switching valve and the flow divider valve device may be configured as a single unit. 【0086】 Furthermore, although the flow divider valve 391 in this embodiment is an electromagnetically proportional controlled valve, it is not limited to this, and may be a pilot-operated valve 315 that operates by an external signal pressure from an electromagnetically proportional valve 314, as shown in Figure 19. This is also true for Embodiments 1 and 2. 【0087】 Furthermore, while the flow diversion valve 391 in this embodiment is a pressure-compensated electromagnetic proportional control flow control valve, it is not limited to this. For example, as shown in Figure 20, it may be an ON-OFF type valve, where the flow rate is constant when ON. This is also true for Embodiments 1 and 2. 【0088】 Furthermore, although the switching valve 304 in this embodiment has been described as having an oil passage 304-3, it is not limited to this configuration, and the oil passage 304-3 may be omitted. [Examples] 【0089】 Next, the fluid pressure circuit according to Example 4 will be described with reference to Figure 21. Note that the description of components that are identical to those in Examples 1 to 3 and therefore overlap will be omitted. 【0090】 As shown in Figure 21, the hydraulic circuit 430 in this embodiment 4 differs from that of embodiment 2 in that a regeneration valve 40 is provided between the hydraulic cylinder 5 and the flow diversion valve device 9, but otherwise the configuration is almost identical. 【0091】 The regeneration valve 40 is connected to oil passages 24-2a and 24-2b between the hydraulic cylinder 5 and the flow diversion valve device 9, and to oil passages 25-1 and 25-2 between the switching valve 204 and the hydraulic cylinder 5. 【0092】 As a result, the oil passage 40-1 in the regeneration valve 40 is positioned closer to the hydraulic cylinder 5 than the oil passages 9-1 and 9-3 in the flow divider valve 91, and since the throttling is omitted, a portion of the return oil can be preferentially guided to the oil passage 40-2. Here, the oil passage 40-1 is a passage with low fluid resistance in this embodiment. Therefore, as with embodiment 3, it is possible to prevent a decrease in the operating speed of the hydraulic cylinder 5. Thus, a passage with low fluid resistance may be provided outside the flow divider valve. 【0093】 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. 【0094】 For example, in the above embodiments 1 to 4, the valve of the present invention was described as a flow-dividing valve, but it is not limited to this, and any valve having a throttle may not have a flow-dividing function. In such a configuration, for example, another passage that is branched and connected to the passage communicating with the valve may be connectable to the regeneration passage. In such a configuration, a throttle may or may not be provided in the middle of the other passage that can be connected to the regeneration passage. 【0095】 Furthermore, in the above embodiments 1 to 4, the flow divider valve was described as being configured to divide the flow to one regeneration passage side and one regenerative mechanism side. However, the invention is not limited to this configuration, and there may be multiple regeneration passages and regenerative mechanisms, each of which may be configured to divide the flow. 【0096】 Furthermore, while embodiments 1 to 4 above illustrate a configuration in which the switching valve is operated by pilot pressure and the diversion valve is operated electrically, for example, both the control valve and the diversion valve may be operated by the same pilot pressure or by electricity. 【0097】 Furthermore, although oil was used as an example of the fluid in the fluid pressure circuit in Examples 1 to 4, it goes without saying that the method can be applied to all fluids, such as water and air. Moreover, the fluid supply source that pressurizes the fluid in the tank is not limited to a hydraulic pump and can be changed in various ways depending on the fluid used in the fluid pressure circuit; for example, it may be an air cylinder or an accumulator. 【0098】 Furthermore, although the above embodiments 1 to 4 were described as having a configuration in which a regenerative motor is connected to the flow divider valve via an oil passage, the invention is not limited to this configuration. A pressure booster for increasing the fluid pressure and an accumulator for storing the fluid may also be provided, or another cylinder device may be provided, and the configuration connected to the flow divider valve may be changed as appropriate. [Explanation of Symbols] 【0099】 1. Drive mechanism 2 Main hydraulic pump 3. Pilot hydraulic pump 4. Switching valve 4-3 Oil passage (part of the regeneration passage) 4-4 Check valve (part of the regeneration passage) 5. Hydraulic Cylinder (Cylinder Device) 5-1 Bottom chamber (one side of the cylinder device) 5-2 Rod chamber (the other side of the cylinder device) 8 tanks 9-1 Oil passage (passage through a throttle) 9-2 aperture 9-3 Oil passage (passage through a throttle) 9-4 aperture 10 regenerative motors 11 Generators 91 Diverter valve (valve) 130 Hydraulic Circuit 40 Regenerative valve 40-2 Oil passage (part of the regeneration passage) 40-3 Check valve (part of the regeneration passage) 204 Switching valve 230 Hydraulic Circuit 304 Switching valve 304-3 Oil passage (part of the regeneration passage) 304-4 Check valve (part of the regeneration passage) 304-6 Oil passage (part of the regeneration passage) 9-6 Oil passage (part of the passage with low fluid resistance) 391 Diverter valve (valve) 315 Pilot-operated valves (valves) 330 Hydraulic Circuit 399 Oil passage (part of a passage with low fluid resistance) 40-1 Oil passage (a passage with low fluid resistance) 430 Hydraulic Circuit R1~R3 ​​Regeneration passage

Claims

[Claim 1] A fluid pressure circuit comprising a fluid supply source and a cylinder device, The device has a valve that branches off a portion of the return fluid from the cylinder device and discharges it through a throttle, and a regeneration passage between the fluid supply source and the cylinder device that allows the return fluid from one side of the cylinder device to flow to the other side of the cylinder device. A fluid channel is provided to supply fluid from the fluid supply source to the other side of the cylinder device. The regeneration passage has one end connected to a valve and the other end connected to the flow path via a check valve that allows fluid to flow toward the other end. The regeneration passage is provided with a fluid pressure circuit, which is connected between the one end and the check valve and has a flow path for discharging fluid to a tank through a throttle. [Claim 2] The fluid pressure circuit according to claim 1, wherein the fluid pressure circuit further has a passage having less fluid resistance than the passage through the throttle in the valve, and the passage with less fluid resistance is able to communicate with the regeneration passage. [Claim 3] The fluid pressure circuit according to claim 2, wherein the passage with low fluid resistance is provided in the valve. [Claim 4] The fluid pressure circuit according to claim 2, wherein two passages are provided through the aforementioned throttling, one of which is capable of communicating with the regeneration passage. [Claim 5] The fluid pressure circuit according to claim 1, further comprising a switching valve provided in the flow path between the fluid supply source and the valve, which controls the inflow and outflow of fluid between the fluid supply source and the cylinder device, and having the regeneration passage within the switching valve. [Claim 6] The fluid pressure circuit according to any one of claims 1 to 5, wherein the regeneration passage is only accessible when the cylinder device is being retracted.

Images