Fluid pressure circuit

Abstract

Provided is a fluid pressure circuit capable of accumulating a fluid having a wide range of pressures. A fluid pressure circuit is provided with: a drive body (1); and a plurality of accumulators (6a, 6b) that accumulate a fluid in accordance with the pressure of the fluid supplied from the drive body (1) side, the accumulation characteristics of the plurality of accumulators (6a, 6b) being different.

Description

Technical Field

[0001] This invention relates to a fluid pressure circuit, and more particularly to a fluid pressure circuit having an accumulator for storing pressure in a working fluid. Background Technology

[0002] In various fields, a fluid pressure circuit is known that uses a working fluid, such as working oil supplied from a fluid supply device like a pump, to drive an actuator. In such a fluid pressure circuit, for example, the following action is also performed: oil discharged from the hydraulic cylinder device, which accompanies the contraction action of the hydraulic cylinder device as an actuator, is stored in an accumulator and regenerated when the hydraulic cylinder device extends.

[0003] For example, a fluid pressure circuit is known that pressurizes working fluid discharged from a hydraulic cylinder device and stores it in an accumulator using a pressurizing device (see Patent Document 1). As an example of such a fluid pressure circuit... Figure 4 The fluid pressure circuit shown mainly consists of a hydraulic pump 501, a reversing valve 502, a hydraulic cylinder device 503, a solenoid switching valve 504, a booster device 505, an accumulator 506, and an oil tank 507.

[0004] The directional control valve 502 is a spring-loaded, three-position, six-way switching valve. When the directional control valve 502 is in the neutral position 502-1, the oil discharged from the hydraulic pump 501 is discharged to the oil tank 507.

[0005] Furthermore, when the directional valve 502 is in the left position 502-2, oil discharged from the hydraulic pump 501 is supplied to the first oil chamber 503-1 of the hydraulic cylinder assembly 503, and a portion of the oil in the second oil chamber 503-2 of the hydraulic cylinder assembly 503 is discharged to the oil tank 507 through the throttle orifice 517, while the other portion flows to the solenoid switching valve 504. As a result, the workpiece W descends.

[0006] With the directional valve 502 in the right position 502-3, a portion of the oil discharged from the hydraulic pump 501 is supplied to the second oil chamber 503-2 of the hydraulic cylinder assembly 503, and the oil in the first oil chamber 503-1 of the hydraulic cylinder assembly 503 is discharged to the oil tank 507. As a result, the workpiece W rises.

[0007] The 504 electromagnetic switching valve is a two-position four-way electromagnetic switching valve.

[0008] The booster device 505 includes a housing 508 and a piston 509. The housing 508 includes a large-diameter cylindrical portion 508a, a small-diameter cylindrical portion 508b, and a partition portion 508c. The partition portion 508c is annular and separates the large-diameter cylindrical portion 508a from the small-diameter cylindrical portion 508b. The piston 509 has a large-diameter portion 509a, a small-diameter portion 509b, and a shaft portion 509c, and is housed within the housing 508 in a manner that allows it to slide axially.

[0009] When the electromagnetic switching valve 504 is demagnetized, it is in the first position 504-1. Oil supplied from the hydraulic cylinder device 503 is introduced into the oil chamber 505-1 of the booster device 505, and the oil in the oil chamber 505-2 is discharged into the oil tank 507. As a result, the piston 509 moves to the right, and the oil in the oil chamber 505-3 is squeezed out and flows into the accumulator 506 through the check valve 510. At the same time, the oil chamber 505-4 of the booster device 505 becomes negative pressure, and the oil in the oil tank 507 is drawn in through the check valve 511.

[0010] On the other hand, when the solenoid switching valve 504 is switched to the second position 504-2, the oil supplied from the hydraulic cylinder device 503 side is introduced into the oil chamber 505-2 of the booster device 505, and the oil in the oil chamber 505-1 is discharged to the oil tank 507. As a result, the piston 509 moves to the left, and the oil in the oil chamber 505-4 is squeezed out and flows into the accumulator 506 through the check valve 512. At the same time, the oil chamber 505-3 of the booster device 505 becomes negative pressure, and the oil in the oil tank 507 is drawn in through the check valve 513.

[0011] When the area of ​​the left side of the large-diameter portion 509a of the piston 509 is A, the area of ​​the right side of the large-diameter portion 509a is B, the area of ​​the right side of the small-diameter portion 509b is C, and the area of ​​the left side of the small-diameter portion 509b is D, according to Pascal's principle, when the electromagnetic switching valve 504 is demagnetized, the oil squeezed out from the oil chamber 505-3 is pressurized to a maximum of A / C times and flows into the accumulator 506. Conversely, when the electromagnetic switching valve 504 is energized, the oil squeezed out from the oil chamber 505-4 is pressurized to a maximum of B / D times and flows into the accumulator 506. Therefore, by repeatedly energizing and demagnetizing the electromagnetic switching valve 504, the oil pressurized by the pressurization device 505 continuously flows into the accumulator 506.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: Japanese Patent Application Publication No. 2017-15130 (page 7) Figure 2 ) Summary of the Invention

[0015] The problem that the invention aims to solve

[0016] exist Figure 4 In such a fluid pressure circuit, depending on the operating conditions of the hydraulic cylinder device 503, such as whether there is a load on the workpiece W, the pressure in the second oil chamber 503-2 of the hydraulic cylinder device 503, that is, the input pressure to the booster device 505, can vary greatly.

[0017] For example, when the load on workpiece W is large and the input pressure of the booster device 505 is as high as 7 MPa, if the boosting ratio of the booster device 505 is set to 3 times and the sealing gas pressure of the accumulator 506 is set to 7 MPa, then... Figure 5 As shown, the output pressure is increased to 21 MPa by the pressure ratio of the booster device 505, thus ensuring a large amount of liquid storage in the accumulator 506.

[0018] On the other hand, when the load on the workpiece W is small and the input pressure to the booster device 505 is as low as 3 MPa, such as Figure 6 As shown, due to the pressure increase ratio of the booster device 505, the output pressure is only boosted to 9MPa, which may result in a decrease in the amount of liquid stored in the accumulator 506.

[0019] This invention was made in view of such a problem, and its purpose is to provide a fluid pressure circuit capable of accumulating fluids with a wide range of pressures.

[0020] Methods for solving problems

[0021] To solve the aforementioned problem, the fluid pressure circuit of the present invention comprises:

[0022] A drive unit; and a plurality of accumulators that store fluid according to the fluid pressure supplied from the drive unit side.

[0023] The energy storage characteristics of the multiple energy storage devices are different.

[0024] Therefore, multiple accumulators with different storage characteristics can be used according to the pressure, thus enabling the storage of a wide range of fluid pressures.

[0025] Alternatively, it may include: a switching valve that switches the fluid supply destination to at least one of the accumulators.

[0026] Therefore, the fluid supply destination can be selected by switching valves, thus enabling any accumulator to preferentially store fluid.

[0027] Alternatively, the switching valve may switch the supply destination to one of the energy storage devices.

[0028] Therefore, the switching valve supplies fluid to one accumulator, thus preventing fluid from moving between accumulators with different storage characteristics. This prevents fluid stored in a higher-pressure accumulator from flowing to a lower-pressure accumulator.

[0029] Alternatively, a pressure sensor for detecting fluid pressure can be installed between the drive body and the accumulator.

[0030] Therefore, the switching valve can be switched based on the fluid pressure detected by the pressure sensor. As a result, the fluid pressure loop can improve the control accuracy in response to changes in conditions.

[0031] Alternatively, the driving body may be a retractable hydraulic cylinder device.

[0032] Therefore, even if the hydraulic pressure of the return oil in the hydraulic cylinder device changes, it can be stored using multiple accumulators with different storage characteristics.

[0033] Alternatively, a pressurization device may be provided between the drive body and the energy storage device.

[0034] Therefore, the high fluid pressure boosted by the booster device can be stored in the accumulator.

[0035] Alternatively, it may have a regeneration switching valve that selectively regenerates the fluid stored in the plurality of accumulators.

[0036] Therefore, an accumulator that can be used for regeneration can be selected by a regeneration switching valve to store fluid at the optimal pressure. Attached Figure Description

[0037] Figure 1 This is a schematic diagram illustrating the fluid pressure circuit in Embodiment 1 of the present invention;

[0038] Figure 2 This is a graph showing the relationship between the output pressure of the booster device and the amount of liquid stored in the accumulator in Example 1;

[0039] Figure 3 This is a schematic diagram illustrating the fluid pressure circuit in Embodiment 2 of the present invention;

[0040] Figure 4 This is a schematic diagram showing an existing fluid pressure circuit;

[0041] Figure 5 This is a graph showing the relationship between the output pressure of the booster device and the amount of liquid stored in the accumulator when the input pressure of the existing booster device is high;

[0042] Figure 6 This is a graph showing the relationship between the output pressure of the booster and the amount of liquid stored in the accumulator when the input pressure of the existing booster is low. Detailed Implementation

[0043] Hereinafter, the method of implementing the fluid pressure circuit of the present invention will be described based on the embodiments.

[0044] [Example 1]

[0045] Reference Figure 1 and Figure 2 The fluid pressure circuit of Example 1 will be described below. Figure 1 The left and right positions of the directional valve and the booster device are explained when viewed from the front.

[0046] The hydraulic circuit of the fluid pressure circuit in Example 1 is used to store the working fluid pressurized by the booster in the accumulator by using the working fluid discharged from the hydraulic cylinder device of the operating machinery, construction machinery, loading and unloading vehicles, automobiles, etc., and to regenerate it to the hydraulic cylinder device.

[0047] like Figure 1 As shown, the hydraulic circuit 101 mainly consists of an actuator (hydraulic cylinder device 1) as the driving body, a hydraulic pump 2, a reversing valve 3, a solenoid switching valve 4, a booster device 5, accumulators 6a and 6b, a supply destination switching valve 7 as a switching valve, an oil tank 8, a regeneration switching valve 9, a pressure sensor 10, check valves 11 to 16, and pipelines 21 to 36.

[0048] Hydraulic pump 2 supplies pressurized oil. The pressurized oil delivered from hydraulic pump 2 flows into directional valve 3 through pipelines 21 and 22 and check valve 11.

[0049] Furthermore, the hydraulic pump 2 in this embodiment is a fixed capacity type, but it can also be a variable capacity type.

[0050] The directional control valve 3 is a spring-loaded, three-position, six-way hydraulic switching valve. In its neutral position 3-1, the directional control valve 3 connects line 21 to line 23. Line 23 is connected to the oil tank 8. Therefore, all the pressurized oil delivered from the hydraulic pump 2 is discharged to the oil tank 8.

[0051] When a hydraulic signal is applied to the left side, the slide moves to the right, and the directional valve 3 switches to the left position 3-2. In the left position 3-2, the directional valve 3 connects line 22 to line 24 and line 25 to line 27.

[0052] Therefore, the pressurized oil delivered from the hydraulic pump 2 flows into the first oil chamber 1-1 of the hydraulic cylinder device 1, and the pressurized oil in the second oil chamber 1-2 of the hydraulic cylinder device 1 is discharged to the oil tank 8 through the throttle orifice 17, and a portion of it flows into the solenoid switching valve 4 through the pipe 28 branching from the pipe 25. As a result, the hydraulic cylinder device 1 contracts, thereby causing the workpiece W to descend.

[0053] On the other hand, when a hydraulic signal is applied to the right side, the slide moves to the left, and the directional valve 3 switches to the right position 3-3. The directional valve 3 in the right position 3-3 connects pipe 22 to pipe 25 and pipe 24 to pipe 27.

[0054] Therefore, the pressurized oil delivered from the hydraulic pump 2 flows into the second oil chamber 1-2 of the hydraulic cylinder device 1, while the pressurized oil in the first oil chamber 1-1 of the hydraulic cylinder device 1 is discharged to the oil tank 8. As a result, the hydraulic cylinder device 1 extends, thereby raising the workpiece W.

[0055] The solenoid switching valve 4 is a spring-biased two-position four-way solenoid switching valve. When the solenoid switching valve 4 is in the biased position 4-1, it connects pipe 28 to pipe 29 and pipe 30 to pipe 26.

[0056] When an electrical signal is applied to solenoid 4a and it is energized, the slide column moves and switches to the starting position 4-2. The solenoid switching valve 4, in the starting position 4-2, connects pipe 28 to pipe 30 and pipe 29 to pipe 26.

[0057] The booster device 5 mainly consists of a housing 51 and a piston 52.

[0058] The shell 51 is formed into a stepped cylindrical shape having a large-diameter cylindrical portion 51a, a small-diameter cylindrical portion 51b, a partition portion 51c, and circular plate portions 51d and 51e.

[0059] The large-diameter cylindrical portion 51a and the small-diameter cylindrical portion 51b are separated by an annular partition 51c. The left end of the large-diameter cylindrical portion 51a is closed by the circular plate portion 51d, and the right end of the small-diameter cylindrical portion 51b is closed by the circular plate portion 51e.

[0060] The piston 52 has a large-diameter cylindrical portion 52a, a small-diameter cylindrical portion 52b, and a connecting shaft portion 52c, and the axes of each are arranged in a roughly straight line.

[0061] The diameter of the large-diameter cylindrical portion 52a is slightly smaller than the inner diameter of the large-diameter cylindrical portion 51a of the housing 51. The large-diameter cylindrical portion 52a can slide along the inner circumferential surface of the large-diameter cylindrical portion 51a.

[0062] The diameter of the small-diameter cylindrical portion 52b is slightly smaller than the inner diameter of the small-diameter cylindrical portion 51b of the housing 51. The small-diameter cylindrical portion 52b can slide along the inner circumferential surface of the small-diameter cylindrical portion 51b.

[0063] The diameter of the connecting shaft portion 52c is slightly smaller than the inner diameter of the partition portion 51c of the housing 51. The connecting shaft portion 52c can slide along the inner circumferential surface of the partition portion 51c of the housing 51.

[0064] The booster device 5 has a first input chamber 5-1, a second input chamber 5-2, a first output chamber 5-3, and a second output chamber 5-4.

[0065] The first input chamber 5-1 is a space surrounded by a large-diameter cylindrical section 51a, a circular plate section 51d, and a large-diameter cylindrical section 52a, and is connected to a pipe 29.

[0066] The second input chamber 5-2 is a space surrounded by a large-diameter cylindrical section 51a, a partition section 51c, and a large-diameter cylindrical section 52a, and is connected to a pipe 30.

[0067] The first output chamber 5-3 is a space surrounded by a small-diameter cylindrical part 51b, a circular plate part 51e, and a small-diameter cylindrical part 52b, and is connected to pipes 31 and 35.

[0068] The second output chamber 5-4 is a space surrounded by a small-diameter cylindrical part 51b, a partition part 51c and a small-diameter cylindrical part 52b, and is connected to pipes 33 and 34.

[0069] When the electromagnetic switching valve 4 is in the demagnetized state, i.e. the biased position 4-1, the pressure oil flowing in the pipeline 28 flows into the first input chamber 5-1 of the booster device 5 through the pipeline 29, and the pressure oil in the second input chamber 5-2 of the booster device 5 is discharged to the oil tank 8 through the pipeline 30 and the pipeline 26.

[0070] As a result, piston 52 moves to the right, and the pressurized oil in the first output chamber 5-3 flows into the destination switching valve 7 through pipeline 31, check valve 13, and pipeline 36. At the same time, the second output chamber 5-4 becomes negative pressure, and oil is drawn into the oil tank 8 through check valve 14 and pipeline 33.

[0071] The pressure-bearing area C on the right side of the small-diameter cylindrical portion 52b of piston 52 is smaller than the pressure-bearing area A on the left side of the large-diameter cylindrical portion 52a. Therefore, by moving piston 52 to the right, the pressure oil squeezed out from the first output chamber 5-3 can be increased to a ratio of A / C.

[0072] When the electromagnetic switching valve 4 is in the energized state, i.e. the initial position 4-2, the pressure oil flowing in the pipeline 28 flows into the second input chamber 5-2 of the booster device 5 through the pipeline 30, and the pressure oil in the first input chamber 5-1 of the booster device 5 is discharged to the oil tank 8 through the pipeline 29 and the pipeline 26.

[0073] As a result, piston 52 moves to the left, and the pressurized oil in the second output chamber 5-4 flows into the supply destination switching valve 7 through pipeline 34, check valve 15, and pipeline 36. At the same time, the first output chamber 5-3 becomes negative pressure, and oil is drawn into the oil tank 8 through check valve 16 and pipeline 35.

[0074] The pressure-bearing area D on the left side of the small-diameter cylindrical portion 52b of piston 52 is smaller than the pressure-bearing area B on the right side of the large-diameter cylindrical portion 52a. Therefore, by moving piston 52 to the left, the pressure oil squeezed out from the second output chamber 5-4 can be increased to a ratio of B / D.

[0075] The supply destination switching valve 7 is a spring-loaded, three-position, four-way solenoid switching valve. When in the neutral position 7-1, the supply destination switching valve 7 closes the pipeline 36.

[0076] The supply destination switching valve 7 has solenoids 7a and 7b. Solenoids 7a and 7b are electrically connected to a control device (not shown).

[0077] When an electrical signal is applied to and the solenoid 7a on the left is energized, the slide moves to the right, and the supply destination switching valve 7 switches to the left position 7-2. The supply destination switching valve 7 in the left position 7-2 connects pipeline 36 to accumulator 6a and accumulator 6b to pipeline 32.

[0078] On the other hand, when an electrical signal is applied to and the solenoid 7b on the right side is energized, the slide moves to the left, and the supply destination switching valve 7 switches to the right position 7-3. The supply destination switching valve 7 in the right position 7-3 connects the pipeline 36 to the accumulator 6b and connects the accumulator 6a to the pipeline 32.

[0079] Accumulators 6a and 6b are so-called gas accumulators, in which a nitrogen-filled gas bladder is assembled within a high-rigidity casing. In this embodiment, the gas pressure sealed into the gas bladder of accumulator 6a is 3 MPa, and the gas pressure sealed into accumulator 6b is 7 MPa. Thus, the oil accumulation characteristics in accumulators 6a and 6b are different.

[0080] Accumulators 6a and 6b are independently connected to the supply destination switching valve 7.

[0081] Furthermore, the sealing gas pressure of accumulators 6a and 6b is not limited to the method of this embodiment; any different sealing gas pressure can be used and can be freely changed. In addition, the accumulator is not limited to gas type; it can also be gravity type, spring type, or even airbag type, piston type, etc., and the structure of the accumulator can be arbitrary.

[0082] The regeneration switching valve 9 is a spring-biased two-position two-way hydraulic switching valve. When the regeneration switching valve 9 is in the biased position 9-1, the pipeline 32 is closed.

[0083] When a hydraulic signal is applied to the right side of the regeneration switching valve 9, the slide moves, and the regeneration switching valve 9 switches to the initial position 9-2. The solenoid 4a in the initial position 9-2 connects the pipeline 32 to the pipeline 37.

[0084] Pipeline 37 is connected to pipeline 25 via check valve 12. In addition, a pressure sensor 10 for detecting the hydraulic pressure in the second oil chamber 1-2 of the hydraulic cylinder device 1 is connected to pipeline 25.

[0085] In such a hydraulic circuit 101, a portion of the pressurized oil in the second oil chamber 1-2 of the hydraulic cylinder device 1 can be stored in accumulators 6a and 6b when the hydraulic cylinder device 1 retracts, and the pressurized oil stored in accumulators 6a and 6b can be regenerated when the hydraulic cylinder device 1 extends.

[0086] Next, the retraction action of the hydraulic cylinder device 1 will be explained.

[0087] During the retraction action of the hydraulic cylinder device 1, the solenoid switching valve 4 is alternately switched to the bias position 4-1 and the starting position 4-2, causing the piston 52 of the booster device 5 to move back and forth repeatedly, thereby continuously supplying the boosted oil to the supply destination switching valve 7. In addition, in this embodiment, the boosting ratio of the booster device 5 is set to 3 times.

[0088] The pressure of the oil supplied to the solenoid switching valve 4 is higher when an external force is applied to the workpiece W than when almost no external force is applied to the workpiece W.

[0089] The supply destination switching valve 7 is switched to either the left position 7-2 or the right position 7-3 by a control device (not shown) based on hydraulic pressure detected by the pressure sensor 10.

[0090] Specifically, when the hydraulic pressure detected by the pressure sensor 10 is less than 7 MPa, the control device switches the supply destination switching valve 7 to the left position 7-2, and when the hydraulic pressure detected by the pressure sensor 10 is 7 MPa or more, it switches the supply destination switching valve 7 to the right position 7-3.

[0091] As an example, when the hydraulic pressure detected by pressure sensor 10 is 3 MPa, the oil is pressurized to 9 MPa by the booster ratio of booster device 5 and flows into supply destination switching valve 7. Supply destination switching valve 7 switches to the left position 7-2, so the oil flows into accumulator 6a with a sealed air pressure of 3 MPa. Thus, as Figure 2 As shown, even with a low input hydraulic pressure, a sufficient amount of oil can be stored in the accumulator 6a.

[0092] Furthermore, when the hydraulic pressure detected by pressure sensor 10 is 7 MPa, the oil is pressurized to 21 MPa by the booster ratio of booster device 5 and flows into supply destination switching valve 7. Supply destination switching valve 7 switches to the right position 7-3, so the oil flows into accumulator 6b with a sealed air pressure of 7 MPa. Thus, as Figure 2As shown, sufficient oil can be stored in accumulator 6b, and even if the input hydraulic pressure is high, it will not flow into accumulator 6a, which has a lower strength, thus preventing accumulator 6a from malfunctioning.

[0093] Next, the extension action of the hydraulic cylinder device 1 will be explained.

[0094] return Figure 1 During the extension action of the hydraulic cylinder device 1, similarly as described above, the supply destination switching valve 7 is switched to either the left position 7-2 or the right position 7-3 by a control device (not shown) based on the hydraulic pressure detected by the pressure sensor 10.

[0095] Additionally, the regeneration switching valve 9 is switched from the biased position 9-1 to the starting position 9-2. As a result, the oil stored in either of the accumulators 6a and 6b is regenerated to the second oil chamber 1-2 of the hydraulic cylinder device 1 via pipeline 32, pipeline 37, check valve 12, and pipeline 25.

[0096] As an example, when the hydraulic pressure detected by the pressure sensor 10 is low (e.g., less than 7 MPa), that is, when almost no external force is applied to the workpiece W, the supply destination switching valve 7 switches to the left position 7-2, and the stored oil in the accumulator 6a is regenerated to the second oil chamber 1-2 of the hydraulic cylinder device 1.

[0097] In addition, when the hydraulic pressure detected by the pressure sensor 10 is high (e.g., above 7 MPa), that is, when an external force is applied to the workpiece W, the supply destination switching valve 7 is switched to the right position 7-3, and the stored oil in the accumulator 6b is regenerated to the second oil chamber 1-2 of the hydraulic cylinder device 1.

[0098] As explained above, accumulators 6a and 6b with different storage characteristics can be selected according to the hydraulic pressure supplied from the supply destination switching valve 7, thus effectively storing oil with a wide range of pressures from 3MPa to 21MPa.

[0099] Furthermore, in the case of storing oil under a wide range of pressures by a single accumulator, a special housing with strength and large capacity that can withstand the pressure at the upper limit of storage is required. However, the hydraulic circuit 101 of this embodiment can store oil under a wide range of pressures by using general accumulators 6a and 6b with different storage characteristics. Therefore, compared with the case of storing oil under a wide range of pressures by a single accumulator, the hydraulic circuit 101 can be constructed simply.

[0100] Furthermore, accumulators 6a and 6b are independently connected to a supply destination switching valve 7, which switches the oil supply destination to either accumulator 6a or 6b. This prevents oil from moving between accumulators 6a and 6b with different storage characteristics. For example, it prevents high-pressure oil stored in the higher-pressure accumulator 6b from flowing to the lower-pressure accumulator 6a. Therefore, the hydraulic pressure within accumulator 6b can be maintained at a high level.

[0101] Furthermore, a pressure sensor 10 is included, which can switch the supply destination switching valve 7 based on the hydraulic pressure detected by the pressure sensor 10. Therefore, the control accuracy for hydraulic pressure changes input to the accumulators 6a and 6b can be improved.

[0102] In addition, the oil flowing out of the second oil chamber 1-2 of the hydraulic cylinder device 1 is pressurized by the booster device 5, thereby increasing the range of hydraulic pressure input to the accumulators 6a and 6b, and enabling effective storage using accumulators 6a and 6b with different storage characteristics according to the input hydraulic pressure.

[0103] In addition, the regeneration switching valve 9 allows the accumulators 6a and 6b to be regenerated according to the force required for the extension action of the hydraulic cylinder device 1.

[0104] Furthermore, in this embodiment, the reversing valve 3, the solenoid switching valve 4, the supply destination switching valve 7, and the regeneration switching valve 9 are illustrated as spool valves, but they can also be lift valves, sliding valves, etc.

[0105] [Example 2]

[0106] Next, refer to Figure 3 The fluid pressure circuit of Example 2 will be described. Furthermore, components identical to those shown in Example 1 will be labeled with the same reference numerals, and repeated descriptions will be omitted.

[0107] like Figure 3 As shown, the hydraulic circuit 201 has a first switching valve 207 and a second switching valve 208 disposed between the booster device 5 and the accumulators 6a and 6b. The first switching valve 207 is disposed on the side of the booster device 5 closer than the second switching valve 208.

[0108] The first switching valve 207 is a spring-centered three-position four-way solenoid switching valve. Pipelines 32, 36, 40, and 41 are connected to the first switching valve 207.

[0109] The first switching valve 207, which is in the neutral position 207-1, closes pipes 32, 36, 40 and 41.

[0110] The first switching valve 207 has solenoids 207a and 207b. When an electrical signal is applied to the left solenoid 207a and it is energized, the slide bar moves to the right, and the first switching valve 207 switches to the left position 207-2. In the left position 207-2, the first switching valve 207 connects pipe 36 and pipe 40, and closes pipe 32 and pipe 41.

[0111] When an electrical signal is applied to and the solenoid 207b on the right side is energized, the slide bar moves to the left, and the first switching valve 207 switches to the right position 207-3. The first switching valve 207 in the right position 207-3 connects pipeline 32 and pipeline 41, and closes pipeline 36 and pipeline 40.

[0112] The second switching valve 208 is a spring-centered three-position four-way solenoid switching valve. Pipelines 40 and 41 and accumulators 6a and 6b are connected to the second switching valve 208.

[0113] In the neutral position 208-1, the second switching valve 208 connects pipeline 40 to accumulators 6a and 6b respectively, and closes pipeline 41. In the neutral position 208-1, a check valve 210 is provided on the flow path connecting pipeline 40 to accumulator 6b.

[0114] The second switching valve 208 has solenoids 208a and 208b. When an electrical signal is applied to the left solenoid 208a and it is energized, the slide moves to the right, and the second switching valve 208 switches to the left position 208-2. In the left position 208-2, the second switching valve 208 connects the pipeline 41 to the accumulator 6b and closes the pipeline 40 to the accumulator 6a.

[0115] When an electrical signal is applied to and the solenoid 208b on the right side is energized, the slide bar moves to the left, and the second switching valve 208 switches to the right position 208-3. In the right position 208-3, the second switching valve 208 connects pipeline 41 to accumulator 6a and closes pipeline 40 to accumulator 6b.

[0116] During the retraction action of the hydraulic cylinder device 1 in this embodiment 2, the first switching valve 207 switches to the left position 207-2, and the second switching valve 208 switches to the neutral position 208-1. As a result, the oil pressurized by the booster device 5 flows into the accumulators 6a and 6b.

[0117] When the hydraulic pressure input from the booster 5 is less than 7 MPa, it accumulates in the accumulator 6a. Conversely, when the hydraulic pressure input from the booster 5 is less than the sealing air pressure of the accumulator 6b, it does not accumulate in the accumulator 6b. In this case, because a check valve 210 is provided, fluid does not flow from the accumulator 6b to the accumulator 6a, and the accumulator 6b can maintain a higher pressure.

[0118] On the other hand, when the hydraulic pressure input from the booster device 5 is 7 MPa or higher, it accumulates in both accumulators 6a and 6b. At this time, the sealed air pressure in accumulator 6a is lower than that in accumulator 6b, so it is easier to accumulate the oil input from the booster device 5.

[0119] During the extension and retraction of the hydraulic cylinder device 1 in this embodiment 2, the first switching valve 207 switches to the right position 207-3. Additionally, the second switching valve 208 switches to the right position 208-3 when the pressure detected by the pressure sensor 10 is low, and switches to the left position 208-2 when the pressure detected by the pressure sensor 10 is high.

[0120] Therefore, during the extension and retraction of the hydraulic cylinder device 1, when the pressure detected by the pressure sensor 10 is low, the stored oil in the accumulator 6a is regenerated, and when the pressure detected by the pressure sensor 10 is high, the stored oil in the accumulator 6b is regenerated.

[0121] In addition, a check valve 210 is provided on the flow path that connects the pipeline 40 at the neutral position 208-1 of the second switching valve 208 to the accumulator 6b. Therefore, when switching from the right position 208-3 to the neutral position 208-1, it can prevent the accumulated oil from flowing from the higher pressure accumulator 6b to the lower pressure accumulator 6a.

[0122] Furthermore, when the hydraulic cylinder device 1 is not in operation, the first switching valve 207 switches to the neutral position 207-1. This prevents oil from flowing out relative to the accumulators 6a and 6b.

[0123] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the specific structure is not limited to these embodiments. Any changes or additions that do not depart from the spirit of the present invention are also included in the present invention.

[0124] For example, in embodiments 1 and 2 above, two types of accumulators 6a and 6b with different storage characteristics are illustrated, but more than three types of accumulators can also be provided. In addition, the number of each type of accumulator can be freely changed.

[0125] Alternatively, when multiple accumulators of various types are installed, accumulators with the same storage characteristics can be connected to each other. That is, a switching valve can supply fluid to multiple accumulators with the same storage characteristics.

[0126] In addition, in the above embodiments 1 and 2, a scheme in which the pressure sensor 10 is disposed between the hydraulic cylinder device 1 and the booster device 5 is illustrated, but the pressure sensor can also be disposed between the booster device and the switching valve.

[0127] Furthermore, in the above embodiments 1 and 2, the driving body was described using hydraulic cylinder device 1 as an example, but the driving body is not limited to cylinder device, and may also be a pump, etc.

[0128] Furthermore, in the above embodiments 1 and 2, an example of accumulating pressure from a booster device to an accumulator was described, but it is also possible to directly accumulate pressure from a hydraulic cylinder device or a pump without using a booster device.

[0129] Furthermore, while embodiments 1 and 2 described above illustrate a hydraulic circuit with a hydraulic cylinder device 1 as the drive unit, the invention is not limited to this. For example, it can also be applied to hydraulic pressure circuits that have a hydraulic motor as the drive unit, store a portion of the return oil during braking in an accumulator, and regenerate it when the hydraulic motor accelerates.

[0130] In addition, in Examples 1 and 2, the fluid pressure circuit was described using a hydraulic circuit for pumping oil as an example, but it is not limited to this. The working fluid can also be a fluid other than oil, and the fluid used can also be changed appropriately.

[0131] In addition, in Examples 1 and 2, the case of a stepped cylindrical shape formed by connecting cylinders with different radial dimensions of the booster device was described, but it is not limited to this, and a shape that can change the area ratio is preferred.

[0132] Furthermore, in Examples 1 and 2, a so-called double-acting configuration is shown in which the pressurizing device pressurizes when the piston moves to both sides of the axial direction. However, it is not limited to this and can also be a so-called single-acting configuration that pressurizes only when the piston moves to one side of the axial direction.

[0133] Symbol Explanation

[0134] 1: Hydraulic cylinder device (actuator, drive body); 2: Hydraulic pump; 3: Electromagnetic directional valve; 4: Electromagnetic switching valve; 5: Pressure boosting device; 6a, 6b: Accumulator; 7: Supply destination switching valve (switching valve); 8: Oil tank; 9: Regeneration switching valve; 10: Pressure sensor; 11-16: Check valve; 21-41: Piping; 101, 201: Hydraulic circuit (fluid pressure circuit); 207: First switching valve; 208: Second switching valve; A-D: Pressure-bearing area.

Claims

1. A fluid pressure circuit comprising: a drive body; and a plurality of accumulators that accumulate fluid in accordance with a fluid pressure supplied from the drive body side. The accumulation characteristics of the plurality of accumulators are different.

2. The fluid pressure circuit according to claim 1, comprising: a switching valve that switches a supply destination of fluid to at least one of the accumulators.

3. The fluid pressure circuit according to claim 2, wherein the switching valve switches the supply destination to one of the accumulators.

4. The fluid pressure circuit according to claim 3, wherein a pressure sensor that detects a fluid pressure is provided between the drive body and the accumulator.

5. The fluid pressure circuit according to claim 1, wherein the drive body is a hydraulic cylinder device that is capable of extension and contraction.

6. The fluid pressure circuit according to claim 1, wherein a pressure increasing device is provided between the drive body and the accumulator.

7. The fluid pressure circuit according to any one of claims 1 to 6, having: a regeneration switching valve that selectively regenerates fluid accumulated in the plurality of accumulators. ​ ​ ​ ​ ​ ​ ​

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