Fluid Control Device

Abstract

To provide a fluid control device that can perform independent metering control with a small number of proportional solenoid valves.SOLUTION: A separate type spool 3A including a first spool 4 and a second spool 5 separate from each other in an axial direction is inserted into a specific spool hole 20A of a housing 2. The first spool 4 establishes communication between a first supply / discharge passage 14 and one of a pump passage 11 and a tank passage 16, and the second spool 5 establishes communication between a second supply / discharge passage 15 and the other of the pump passage 11 and the tank passage 16. The housing 2 includes a first pilot chamber 7A faced by an end surface 4a of the first spool 4 on the side opposite to the second spool, and a second pilot chamber 7B faced by an end surface 5a of the second spool 5 on the side opposite to the first spool 4. A portion between the first spool 4 and the second spool 5 in the specific spool hole 20A constitutes a third pilot chamber 7C, and the housing 2 includes a pilot passage 6c communicating with the third pilot chamber 7C.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a fluid control device for controlling fluid supplied from a hydraulic pump to a plurality of hydraulic actuators. [Background technology]

[0002] A fluid control device for controlling fluid supplied from a hydraulic pump to a plurality of hydraulic actuators has been known. For example, the fluid control device includes a housing having a plurality of spools for the plurality of hydraulic actuators that are bidirectionally operated by the supply of fluid, and a plurality of spool holes into which the spools are inserted, respectively.

[0003] The housing has a pump passage and a tank passage in addition to the spool bore, and has first and second supply / discharge passages for each spool. When each spool is in a neutral position, the first and second supply / discharge passages are blocked from the pump passage and the tank passage, and when each spool moves from the neutral position, one of the first and second supply / discharge passages communicates with the pump passage, and the other communicates with the tank passage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-241702 Summary of the Invention [Problem to be solved by the invention]

[0005] For hydraulic actuators that operate in both directions by supplying fluid, there is a demand for independent metering control on the meter-in side or the meter-out side regardless of the direction of operation. For example, Patent Document 1 discloses an independent metering valve that achieves this.

[0006] 8, the independent metering valve 100 disclosed in Patent Document 1 has a pump port 101, a pair of supply and discharge ports 102 and 103, and a tank port 104. Furthermore, the independent metering valve 100 includes a first spool 130 that opens and closes communication between the pump port 101 and the supply and discharge port 102, a second spool 140 that opens and closes communication between the supply and discharge port 102 and the tank port 104, a third spool 150 that opens and closes communication between the pump port 101 and the supply and discharge port 103, and a fourth spool 160 that opens and closes communication between the supply and discharge port 103 and the tank port 104.

[0007] Patent Document 1 describes the first to fourth spools 130 to 160 as "electrohydraulic displacement control." This presumably means that an electrical signal is converted into a pilot pressure, and the spools are displaced by the pilot pressure. In such a configuration, solenoid proportional valves are generally used. In other words, the independent metering valve 100 requires four solenoid proportional valves. The solenoid proportional valves may be incorporated into the independent metering valve 100, or may be connected to the independent metering valve 100 by piping.

[0008] Since the independent metering valve 100 of Patent Document 1 uses four spools, it is desirable to reduce the number of spools. In this regard, it is conceivable to integrate the first spool 130 and the second spool 140, and to integrate the third spool 150 and the fourth spool 160. Even with this configuration, independent metering control is possible. However, the number of required solenoid proportional valves remains four.

[0009] Therefore, an object of the present disclosure is to provide a fluid control device that is capable of independent metering control with a small number of electromagnetic proportional valves. [Means for solving the problem]

[0010] The present disclosure provides a hydraulic actuator comprising: a plurality of spools for a plurality of hydraulic actuators that are bidirectionally actuated by the supply of fluid; and a housing including a plurality of spool holes into which the plurality of spools are inserted, a pump passage, a tank passage, and a first supply / discharge passage and a second supply / discharge passage for each of the plurality of spools, wherein at least one of the plurality of spools is a spaced-apart spool including a first spool and a second spool that are spaced apart from each other in the axial direction, the plurality of spool holes including a specific spool hole into which the spaced-apart spool is inserted, and the first spool either blocks the first supply / discharge passage from both the pump passage and the tank passage or blocks the first supply / discharge passage from the pump passage. the second spool either connects the second supply / discharge passage to the pump passage or to one of the tank passages, the second spool either blocks the second supply / discharge passage from both the pump passage and the tank passage or connects the second supply / discharge passage to the other of the pump passage and the tank passage, the housing includes a first pilot chamber facing an end face of the first spool opposite to the second spool and a second pilot chamber facing an end face of the second spool opposite to the first spool, a portion of the specific spool hole between the first spool and the second spool constitutes a third pilot chamber, and the housing includes a pilot passage communicating with the third pilot chamber. [Effects of the Invention]

[0011] According to the present disclosure, a fluid control device capable of independent metering control with a small number of electromagnetic proportional valves is provided. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a side view of a fluid control device according to one embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 2 is a hydraulic circuit diagram including the fluid control device. [Figure 6]FIG. 10 is a cross-sectional view of a fluid control device according to a modified example. [Figure 7] FIG. 10 is a cross-sectional view of another modified example of a fluid control device. [Figure 8] FIG. 1 is a hydraulic circuit diagram including a conventional fluid control device. DETAILED DESCRIPTION OF THE INVENTION

[0013] 1 to 4 show a fluid control device 1 according to one embodiment, and Fig. 5 shows a hydraulic circuit diagram including the fluid control device 1. This fluid control device 1 controls the fluid supplied from a hydraulic pump 10a to a plurality of hydraulic actuators, and is disposed between the hydraulic pump 10a and the plurality of hydraulic actuators in the hydraulic circuit. The fluid flowing in the hydraulic circuit is typically oil, but may be a liquid other than oil.

[0014] In this embodiment, all hydraulic actuators are hydraulic actuators 10d that operate in two directions when supplied with fluid. In Figure 5, the hydraulic actuators 10d are double-acting cylinders, but some or all of the hydraulic actuators 10d may be hydraulic motors. However, the hydraulic actuators may also include hydraulic actuators that operate in one direction when supplied with fluid (for example, single-acting cylinders).

[0015] In this embodiment, the number of hydraulic actuators 10d is five. Note that, from the viewpoint of simplifying the drawing, only two hydraulic actuators 10d are shown in Fig. 5. However, the number of hydraulic actuators 10d is not limited to this and can be changed as appropriate.

[0016] The fluid control device 1 includes multiple spools 3 for multiple hydraulic actuators 10d and a housing 2 that slidably holds these spools 3. When the hydraulic actuators include hydraulic actuators that operate in one direction when supplied with fluid, the fluid control device 1 may include, in addition to the spools 3, spools for the hydraulic actuators that operate in one direction when supplied with fluid. In this embodiment, the number of spools 3 is the same as the number of hydraulic actuators 10d, but when two hydraulic pumps 10a are used, two spools 3 may be used for one hydraulic actuator 10d so that the fluids discharged from the hydraulic pumps 10a are joined and supplied to the hydraulic actuator 10d.

[0017] The spools 3 are parallel to each other and lined up in a specific direction. In this embodiment, the spools 3 are lined up in a single row so that the center lines of all the spools 3 are located on the same plane parallel to the specific direction. However, the center lines of all the spools 3 do not have to be located on the same plane parallel to the specific direction, and the center lines of some of the spools 3 may be located away from that plane. Alternatively, the spools 3 may be lined up in two rows.

[0018] The housing 2 includes a plurality of spool holes 20 into which spools 3 are respectively inserted. That is, the spool holes 20 are also aligned in the specific direction. The housing 2 also includes a pump passage 11 and a tank passage 16 that extend in the specific direction. As shown in FIG. 5, the pump passage 11 forms a pump port 1a on the surface of the housing 2, and this pump port 1a is connected to a hydraulic pump 10a by a pump piping. The tank passage 16 forms a tank port 1b on the surface of the housing 2, and this tank port 1b is connected to a hydraulic pump 10a by a pump piping. 1b is connected to the tank 10b by tank piping.

[0019] 2 and 4, in this embodiment, the tank passage 16 branches into two branch passages 16a and 16b that extend in the specific direction within the housing 2. The pump passage 11 passes near the center of the spool 3, and the branch passages 16a and 16b of the tank passage 16 pass near both ends of the spool 3. However, the configurations of the pump passage 11 and the tank passage 16 can be changed as appropriate.

[0020] Furthermore, the housing 2 includes a first supply / discharge passage 14 and a second supply / discharge passage 15 for each of the spools 3. In other words, the number of sets of first supply / discharge passages 14 and second supply / discharge passages 15 is the same as the number of spools 3 for the multiple hydraulic actuators 10d that operate bidirectionally by supplying fluid. The first supply / discharge passage 14 and the second supply / discharge passage 15 form a pair of supply / discharge ports 1d on the surface of the housing 2, and these supply / discharge ports 1d are connected to the hydraulic actuators 10d by a pair of supply / discharge pipes.

[0021] In this embodiment, two spools 3 are spaced spools 3A shown in Fig. 2, and three spools 3 are integrated spools 3B shown in Fig. 4. The integrated spools 3B and the spaced spools 3A are alternately arranged. That is, the integrated spools 3B are located between the spaced spools 3A.

[0022] However, the arrangement of the integrated spool 3B and the spaced spools 3A is not limited to this, and for example, the spaced spools 3A may be adjacent to each other. Also, as long as the spool 3 includes at least one spaced spool 3A, the ratio of the number of integrated spools 3B to the number of spaced spools 3A can be changed as appropriate. For example, all of the spools 3 may be spaced spools 3A.

[0023] The housing 2 includes a first pilot chamber 7A, a second pilot chamber 7B, and a third pilot chamber 7C for each spaced spool 3A, and a first pilot chamber 7D and a second pilot chamber 7E for each integral spool 3B.

[0024] In this embodiment, the housing 2 includes a rectangular parallelepiped housing main body 2A extending in the specific direction and a block 2B extending in the specific direction along one side of the housing main body 2A. The housing 2 also includes the same number of first covers 2C and second covers 2D as the number of separated spools 3A, and the same number of first covers 2E and second covers 2F as the number of integrated spools 3B. However, the configuration of the housing 2 is not limited to this and can be modified as appropriate. For example, a portion of the first cover 2C and the first cover 2E may be integrated to form a block extending in the specific direction.

[0025] The housing body 2A has a first side surface 2Aa and a second side surface 2Ab that are perpendicular to the axial direction of the spool 3, and a third side surface 2Ac and a fourth side surface 2Ad that are parallel to the specific direction and the axial direction of the spool 3. The block 2B is attached to the fourth side surface 2Ad, the first covers 2C and 2E are attached to the first side surface 2Aa, and the second covers 2D and 2F are attached to the second side surface 2Ab.

[0026] In this embodiment, the above-mentioned pump passage 11 is formed between the spool hole 20 and the third side surface 2Ac, and the above-mentioned tank passage 16 is formed between the spool hole 20 and the fourth side surface 2Ad. Note that the pump passage 11 may branch into two branch passages extending in the specific direction within the housing 2. In this case, one branch passage may be located between the spool hole 20 and the third side surface 2Ac, and the other branch passage may be located between the spool hole 20 and the fourth side surface 2Ad.

[0027] In this embodiment, the first supply / discharge passage 14 and the second supply / discharge passage 15 for the separated spool 3A and the first supply / discharge passage 14 and the second supply / discharge passage 15 for the integrated spool 3B are formed between the spool hole 20 and the third side surface 2Ac. However, the first supply / discharge passage 14 and the second supply / discharge passage 15 for the integrated spool 3B may be formed between the spool hole 20 and the fourth side surface 2Ad.

[0028] Of the spool holes 20, the spool hole 20 into which the separated spool 3A is inserted is a specific spool hole 20A, and the spool hole 20 into which the integrated spool 3B is inserted is a normal spool hole 20B.

[0029] Next, the structure around the integrated spool 3B and the normal spool hole 20B will be described in detail with reference to FIG.

[0030] The first cover 2E has a container-like shape, and the opening of the first cover 2E is closed by the first side surface 2Aa of the housing main body 2A, thereby forming a first pilot chamber 7D. Similarly, the second cover 2F has a container-like shape, and the opening of the second cover 2F is closed by the second side surface 2Ab of the housing main body 2A, thereby forming a second pilot chamber 7E.

[0031] Normal spool hole 20B is a through-hole formed in housing main body 2A so as to straddle first pilot chamber 7D and second pilot chamber 7E. Integrated spool 3B extends across first supply / discharge passage 14 and second supply / discharge passage 15, and has an end face 3a facing first pilot chamber 7D and an end face 3b facing second pilot chamber 7E.

[0032] The integrated spool 3B moves between a neutral position where the first supply and discharge passage 14 and the second supply and discharge passage 15 are isolated from both the pump passage 11 and the tank passage 16, a first position (right position in Figure 5) where the first supply and discharge passage 14 is connected to the pump passage 11 and the second supply and discharge passage 15 is connected to the tank passage 16, and a second position (left position in Figure 5) where the first supply and discharge passage 14 is connected to the tank passage 16 and the second supply and discharge passage 15 is connected to the pump passage 11.

[0033] More specifically, the housing main body 2A is formed with a first inlet annular groove 2a, a second inlet annular groove 2b, a first intermediate annular groove 2c, a second intermediate annular groove 2d, a first outlet annular groove 2e, and a second outlet annular groove 2f, which are recessed radially outward from the normal spool bore 20B. The first inlet annular groove 2a, the first intermediate annular groove 2c, and the first outlet annular groove 2e are aligned in this order from the center of the normal spool bore 20B toward the first cover 2E, and the second inlet annular groove 2b, the second intermediate annular groove 2d, and the second outlet annular groove 2f are aligned in this order from the center of the normal spool bore 20B toward the second cover 2F.

[0034] The housing main body 2A is also formed with a bridge passage 19 that, together with the normal spool bore 20B, surrounds the pump passage 11, and a communication hole 18 that connects the bridge passage 19 to the pump passage 11. The communication hole 18 extends from the pump passage 11 in the opposite direction to the normal spool bore 20B and is connected to the center of the bridge passage 19.

[0035] Both ends of the bridge passage 19 are connected to the first inlet annular groove 2a and the second inlet annular groove 2b. 2a and a second inlet annular groove 2b It is connected to the normal spool hole 20B via

[0036] The housing body 2A is provided with a load check valve 8C that opens and closes the opening of the communication hole 18 to the bridge passage 19. The load check valve 8C allows flow from the pump passage 11 to the bridge passage 19 but prohibits flow in the opposite direction.

[0037] Specifically, the load check valve 8C includes a main body 83 fixed to the housing main body 2A, a valve element 81 slidably held in the main body 83, and a spring 82 disposed between the main body 83 and the valve element 81. Note that the structure of the load check valve 8C is well known, and therefore further detailed description will be omitted.

[0038] The first supply / discharge passage 14 and the second supply / discharge passage 15 for the integrated spool 3B are connected to the first intermediate annular groove 2c and the second intermediate annular groove 2d, respectively, and the branch passages 16a and 16b of the tank passage 16 are connected to the first outflow annular groove 2e and the second outflow annular groove 2f, respectively.

[0039] The integrated spool 3B includes a plurality of lands 31a-31f and a plurality of small diameter portions 32a-32e interposed between these lands 31a-31f. The position where the integrated spool 3B moves from the neutral position toward the first cover 2E is the first position, and the position where the integrated spool 3B moves from the neutral position toward the second cover 2F is the second position.

[0040] A spring 76 is disposed within the second pilot chamber 7E to apply a biasing force to the integrated spool 3B to maintain the integrated spool 3B in a neutral position. The spring 76 directly biases the integrated spool 3B toward the first cover 2E via a spring seat. Meanwhile, a headed rod 75 is attached to the end face 3b of the integrated spool 3B, and the spring 76 biases the integrated spool 3B toward the second cover 2F via the spring seat and the headed rod 75.

[0041] In this embodiment, a first solenoid proportional valve 64 for the first pilot chamber 7D is attached to the first cover 2E, and a second solenoid proportional valve 65 (see FIG. 1) for the second pilot chamber 7E is attached to the block 2B. As shown in FIG. 5, the first solenoid proportional valve 64 outputs secondary pressure to the first pilot chamber 7D through the first pilot passage 6d, and the second solenoid proportional valve 65 outputs secondary pressure to the second pilot chamber 7E through the second pilot passage 6e. To simplify the drawing, the second pilot passage 6e is not shown in FIG. 4.

[0042] Next, the structure around the spaced spool 3A and the specific spool hole 20A will be described in detail with reference to FIGS.

[0043] The first cover 2C has a container-like shape, and a first pilot chamber 7A is formed by closing an opening of the first cover 2C with a first side surface 2Aa of the housing main body 2A. Similarly, the second cover 2D has a container-like shape, and a second pilot chamber 7B is formed by closing an opening of the second cover 2D with a second side surface 2Ab of the housing main body 2A. In this embodiment, the first cover 2C is divided into a cylindrical portion and a lid portion, but the configuration of the first cover 2C is not limited to this.

[0044] The specific spool hole 20A is a through-hole formed in the housing main body 2A so as to straddle the first pilot chamber 7A and the second pilot chamber 7B. The spaced-type spool 3A includes a first spool 4 and a second spool 5 that are spaced apart from each other in the axial direction within the specific spool hole 20A. The portion of the specific spool hole 20A between the first spool 4 and the second spool 5 forms the third pilot chamber 7C described above.

[0045] That is, the end face 4a of the first spool 4 opposite the second spool 5 faces the first pilot chamber 7A, and the end face 4b on the second spool 5 side faces the third pilot chamber 7C. Similarly, the end face 5a of the second spool 5 opposite the first spool 4 faces the second pilot chamber 7B, and the end face 5b on the first spool 4 side faces the third pilot chamber 7C.

[0046] The first spool 4 moves between a neutral position where the first supply / discharge passage 14 is isolated from both the pump passage 11 and the tank passage 16, a first position (left position in Figure 5) where the first supply / discharge passage 14 is isolated from the tank passage 16 but communicates with the pump passage 11, and a second position (right position in Figure 5) where the first supply / discharge passage 14 is isolated from the pump passage 11 but communicates with the tank passage 16.

[0047] The second spool 5 moves between a neutral position where the second supply / discharge passage 15 is isolated from both the pump passage 11 and the tank passage 16, a first position (right-hand position in Figure 5) where the second supply / discharge passage 15 is isolated from the pump passage 11 but communicates with the tank passage 16, and a second position (left-hand position in Figure 5) where the second supply / discharge passage 15 is isolated from the tank passage 16 but communicates with the pump passage 11.

[0048] That is, when the first spool 4 and the second spool 5 are both positioned in the first position or the second position, the first spool 4 connects the first supply / discharge passage 14 to either the tank passage 16 or the pump passage 11, and the second spool 5 connects the second supply / discharge passage 15 to the other of the tank passage 16 and the pump passage 11.

[0049] More specifically, the housing main body 2A is formed with a first inlet annular groove 21, a first intermediate annular groove 23, and a first outlet annular groove 25 recessed radially outward from the specific spool hole 20A in an area overlapping with the first spool 4. The first inlet annular groove 21, the first intermediate annular groove 23, and the first outlet annular groove 25 are aligned in this order from the center of the specific spool hole 20A toward the first cover 2C.

[0050] Additionally, the housing main body 2A is formed with a second inlet annular groove 22, a second intermediate annular groove 24, and a second outlet annular groove 26 recessed radially outward from the specific spool hole 20A in an area overlapping with the second spool 5. The second inlet annular groove 22, the second intermediate annular groove 24, and the second outlet annular groove 26 are aligned in this order from the center of the specific spool hole 20A toward the second cover 2D.

[0051] Furthermore, the housing main body 2A is formed with a bridge passage 13 that surrounds the pump passage 11 together with the specific spool hole 20A, and a communication hole 12 that connects the bridge passage 13 to the pump passage 11. The communication hole 12 extends from the pump passage 11 in the opposite direction to the specific spool hole 20A and is connected to the center of the bridge passage 13.

[0052] Both ends of the bridge passage 13 are connected to the first inlet annular groove 21 and the second inlet annular groove 22. In other words, the bridge passage 13 is connected to the specific spool hole 20A via the first inlet annular groove 21 and the second inlet annular groove 22 on both sides of the third pilot chamber 7C.

[0053] Housing body 2A is provided with a load check valve 8A that opens and closes the opening of communication hole 12 to bridge passage 13. Load check valve 8A allows flow from pump passage 11 to bridge passage 13 but prohibits reverse flow. The structure of load check valve 8A is the same as that of load check valve 8C described above.

[0054] The first supply / discharge passage 14 and the second supply / discharge passage 15 for the spaced-apart spool 3A are connected to the first intermediate annular groove 23 and the second intermediate annular groove 24, respectively, and the branch passages 16a and 16b of the tank passage 16 are connected to the first outflow annular groove 25 and the second outflow annular groove 26, respectively.

[0055] The first spool 4 includes a first land portion 45 that forms the end surface 4b and opens and closes the first inlet annular groove 21, a second land portion 43 that is located between the first intermediate annular groove 23 and the first outlet annular groove 25, and a third land portion 41 that forms the end surface 4a and is located outside the specific spool hole 20A with respect to the first outlet annular groove 25. The first spool 4 further includes a first small diameter portion 44 that connects the first land portion 45 and the second land portion 43, and a second small diameter portion 42 that connects the second land portion 43 and the third land portion 41. As shown in FIG. 2, the neutral position is when the first land portion 45 closes the first inlet annular groove 21.

[0056] When the first spool 4 moves from the neutral position toward the second spool 5, the first land portion 45 opens the first inlet annular groove 21, and the first inlet annular groove 21 communicates with the first intermediate annular groove 23. This is the first position. Conversely, when the first spool 4 moves from the neutral position in the direction away from the second spool 5, the first intermediate annular groove 23 communicates with the first outlet annular groove 25. This is the second position.

[0057] The second spool 5 includes a first land portion 55 constituting the end surface 5b and located closer to the center of the specific spool hole 20A than the second inlet annular groove 22, a second land portion 53 that opens and closes the second intermediate annular groove 24, and a third land portion 51 constituting the end surface 5a and located closer to the outer side of the specific spool hole 20A than the second outlet annular groove 26. The second spool 5 further includes a first small diameter portion 54 that connects the first land portion 55 and the second land portion 53, and a second small diameter portion 52 that connects the second land portion 53 and the third land portion 51. As shown in FIG. 2, the neutral position is when the second land portion 53 closes the second intermediate annular groove 24.

[0058] When the second spool 5 moves from the neutral position toward the first spool 4, the second land portion 53 opens the second intermediate annular groove 24, and the second intermediate annular groove 24 communicates with the second outlet annular groove 26. This is the first position. Conversely, when the second spool 5 moves from the neutral position in the opposite direction to the first spool 4, the second land portion 53 opens the second intermediate annular groove 24, and the second intermediate annular groove 24 communicates with the second inlet annular groove 22. This is the second position.

[0059] 1 are merely examples, and the shapes of the first spool 4 and the second spool 5 may be changed as appropriate. For example, the shapes of the first spool 4 and the second spool 5 may be interchanged.

[0060] A first spring 72 is disposed within the first pilot chamber 7A, and applies a biasing force to the first spool 4 to maintain the first spool 4 in a neutral position. The first spring 72 directly biases the first spool 4 toward the second spool 5 via a spring seat. Meanwhile, a headed rod 71 is attached to the end face 4a of the first spool 4, and the first spring 72 biases the first spool 4 in the opposite direction to the second spool 5 via the spring seat and the headed rod 71.

[0061] Similarly, a second spring 74 is disposed within the second pilot chamber 7B, and applies a biasing force to the second spool 5 to maintain the second spool 5 in a neutral position. The second spring 74 directly biases the second spool 5 toward the first spool 4 via a spring seat. Meanwhile, a headed rod 73 is attached to the end face 5a of the second spool 5, and the second spring 74 biases the second spool 5 in the opposite direction to the first spool 4 via the spring seat and the headed rod 73.

[0062] The first spring 72 and the second spring 74 have the same configuration. That is, the biasing force that the first spring 72 applies to the first spool 4 and the biasing force that the second spring 74 applies to the second spool 5 are equal.

[0063] As shown in Fig. 5, the housing 2 includes a first pilot passage 6a communicating with the first pilot chamber 7A, a second pilot passage 6b communicating with the second pilot chamber 7B, and a third pilot passage 6c communicating with the third pilot chamber 7C. To simplify the drawing, the first pilot passage 6a and the second pilot passage 6b are omitted from Fig. 2.

[0064] In this embodiment, a first solenoid proportional valve 61 that outputs secondary pressure to first pilot chamber 7A through first pilot passage 6a is attached to first cover 2C. Also, a second solenoid proportional valve 62 (see FIG. 1) that outputs secondary pressure to second pilot chamber 7B through second pilot passage 6b, and a third solenoid proportional valve 63 that outputs secondary pressure to third pilot chamber 7C through third pilot passage 6c are attached to block 2B. In other words, third solenoid proportional valve 63 is attached to housing 2 at a position opposite to load check valve 8A with respect to specific spool hole 20A.

[0065] 5, the housing 2 includes a primary pressure passage 60 connected to a first solenoid proportional valve 61, a second solenoid proportional valve 62, and a third solenoid proportional valve 63 for the separated spool 3A, and the first solenoid proportional valve 64 and second solenoid proportional valve 65 for the integrated spool 3B described above. The primary pressure passage 60 forms a primary pressure port 1c on the surface of the housing 2, and this primary pressure port 1c is connected to the auxiliary pump 10c by a primary pressure piping. The housing 2 also includes a tank passage 66 that connects the solenoid proportional valves 61 to 65 with the tank passage 16 described above.

[0066] 1, the third electromagnetic proportional valve 63 is located on a plane P perpendicular to the specific direction in which the spools 3 are arranged and which is spaced apart from the plane P passing through the center of the specific spool hole 20A in the specific direction. However, the third electromagnetic proportional valve 63 may also be located on the plane P.

[0067] In this embodiment, the third pilot passage 6c is located on the opposite side of the pump passage 11 from the load check valve 8A in the specific direction and in the direction perpendicular to the axial direction of the spaced spool 3A (i.e., the left-right direction in FIG. 2). 6c may be located on the same side of the pump passage 11 as the load check valve 8A.

[0068] More specifically, a central annular groove 27 is formed in the housing body 2A, recessed radially outward from the specific spool hole 20A between the first spool 4 and the second spool 5. Furthermore, as shown in FIG. 3, a recess 28 is formed in the housing body 2A, which is continuous with the central annular groove 27 and recessed radially outward from the specific spool hole 20A so as to be pointed. The third pilot passage 6c is connected to this recess 28. The central annular groove 27 and the recess 28, together with the portion of the specific spool hole 20A between the first spool 4 and the second spool 5, form a third pilot chamber 7C.

[0069] In this embodiment, the recess direction of the recess 28 is opposite the load check valve 8A when viewed from the center of the specific spool hole 20A, and is oblique to the above-mentioned plane P. Therefore, the opening of the third pilot passage 6c to the third pilot chamber 7C is located away from plane P. However, the opening of the third pilot passage 6c to the third pilot chamber 7C may be located on plane P.

[0070] In the present embodiment, the third pilot passage 6c extends downward from the recess 28 in Fig. 2, then bends to the right in Fig. 2, and then bends upward in Fig. 2. However, the shape of the third pilot passage 6c can be changed as appropriate.

[0071] Furthermore, in this embodiment, the housing main body 2A is formed with a regeneration passage 17 for guiding the fluid flowing from the second supply / discharge passage 15 into the specific spool hole 20A to the first supply / discharge passage 14. The regeneration passage 17 may be a passage for guiding the fluid flowing from the first supply / discharge passage 14 into the specific spool hole 20A to the second supply / discharge passage 15. However, the regeneration passage 17 can be omitted. Note that, to simplify the drawing, the regeneration passage 17 and related configurations are not shown in FIG. 5.

[0072] The regeneration passage 17 is located on the opposite side of the load check valve 8A with respect to the specific spool hole 20A. The regeneration passage 17 extends from the second intermediate annular groove 24 to the right in FIG. 2, then bends downward in FIG. 2, and then bends left in FIG. 2 to connect to the first intermediate annular groove 23. The third pilot passage 6c partially overlaps with the regeneration passage 17 when viewed from the specific direction. Therefore, the regeneration passage 17 and the third pilot passage 6c can be formed on the opposite side of the specific spool hole 20A from the load check valve 8A.

[0073] The housing body 2A also slidably holds a spool 9 that switches between permitting and prohibiting the flow of fluid through the regeneration passage 17, i.e., switching between performing and not performing fluid regeneration. A cover 2G is attached to the second side surface 2Ab of the housing body 2A, and this cover 2G forms a pilot chamber 7F for operating the spool 9.

[0074] Furthermore, the housing body 2A is provided with a regeneration valve 8B that allows fluid to flow through the regeneration passage 17 only when the pressure in the second supply / discharge passage 15 is higher than the pressure in the first supply / discharge passage 14. The structure of the regeneration valve 8B is the same as the structures of the load check valves 8A and 8C.

[0075] As described above, the fluid control device 1 of this embodiment uses two spools, the first spool 4 and the second spool 5, to bidirectionally operate the hydraulic actuator 10d connected to the first supply / discharge passage 14 and the second supply / discharge passage 15. Furthermore, because the first spool 4 and the second spool 5 are independent of each other, the first spool 4 can be moved in response to the pressure difference between the first pilot chamber 7A and the third pilot chamber 7C, and the second spool 5 can be moved in response to the pressure difference between the second pilot chamber 7B and the third pilot chamber 7C. This enables independent metering control on the meter-in side and the meter-out side regardless of the direction in which the hydraulic actuator 10d operates. Furthermore, because the number of pilot chambers is three, the number of required solenoid proportional valves can be reduced to three. In other words, independent metering control is possible using three solenoid proportional valves for one hydraulic actuator 10d.

[0076] For example, when fluid is supplied from the first supply / discharge passage 14 to the hydraulic actuator 10d and discharged from the hydraulic actuator 10d to the second supply / discharge passage 15, the secondary pressure of the third electromagnetic proportional valve 63 is set to zero, i.e., a state is established in which fluid can be discharged from the third pilot chamber 7C to the tank via the third electromagnetic proportional valve 63, and the secondary pressures of the first electromagnetic proportional valve 61 and the second electromagnetic proportional valve 62 are increased from zero. At this time, if the secondary pressures of the first electromagnetic proportional valve 61 and the second electromagnetic proportional valve 62 are the same, independent metering control is not performed. However, if the secondary pressure of the first electromagnetic proportional valve 61 is lower than the secondary pressure of the second electromagnetic proportional valve 62, meter-in control can be performed by the first electromagnetic proportional valve 61, and if the secondary pressure of the second electromagnetic proportional valve 62 is lower than the secondary pressure of the first electromagnetic proportional valve 61, meter-out control can be performed by the second electromagnetic proportional valve 62.

[0077] On the other hand, when fluid is supplied to hydraulic actuator 10d from second supply / discharge passage 15 and discharged from hydraulic actuator 10d to first supply / discharge passage 14, if the secondary pressure of third electromagnetic proportional valve 63 is increased from zero while the secondary pressure of first electromagnetic proportional valve 61 and the secondary pressure of second electromagnetic proportional valve 62 are set to zero, that is, while fluid can be discharged from first pilot chamber 7A to tank via first electromagnetic proportional valve 61 and from second pilot chamber 7B to tank via second electromagnetic proportional valve 62, independent metering control is not performed. However, if the secondary pressure of first electromagnetic proportional valve 61 is greater than zero, meter-out control can be performed by first electromagnetic proportional valve 61, and if the secondary pressure of second electromagnetic proportional valve 62 is greater than zero, meter-in control can be performed by second electromagnetic proportional valve 62.

[0078] In addition, in this embodiment, the opening of the third pilot passage 6c to the third pilot chamber 7C is offset from the center of the specific spool hole 20A in the specific direction in which the spools 3 are aligned, thereby improving the design freedom around the specific spool hole 20A.

[0079] Furthermore, in this embodiment, because the third pilot passage 6c is connected to the recess 28, the connection position between the third pilot chamber 7C and the third pilot passage 6c can be set to any position. In particular, when the opening of the third pilot passage 6c is offset from the center of the specific spool hole 20A in the specific direction in which the spools 3 are aligned, the opening of the third pilot passage 6c can be significantly offset by the recess 28.

[0080] Furthermore, in this embodiment, the third pilot passage 6c is located on the opposite side of the pump passage 11 from the load check valve 8A, so that the passages formed inside the housing 2 can be prevented from becoming complicated.

[0081] Furthermore, in this embodiment, the integrated spool 3B is located between the spaced spools 3A. If the spaced spools 3A were adjacent to each other, three pilot passages and three solenoid proportional valves would be required for each spaced spool 3A, which would require the pilot passages and solenoid proportional valves to be closely spaced. In contrast, if the integrated spool 3B is located between the spaced spools 3A as in this embodiment, the need for such closely spaced arrangement of the pilot passages and solenoid proportional valves can be alleviated.

[0082] (Variation) The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure.

[0083] For example, central annular groove 27 may be omitted, and recess 28 may be recessed directly from specific spool hole 20A. Alternatively, recess 28 may be omitted in addition to central annular groove 27, and third pilot passage 6c may be directly connected to specific spool hole 20A.

[0084] As shown in FIG. 6, the first spool 4 may also include a first land portion 48 that forms the end face 4b and opens and closes the first inlet annular groove 21, a second land portion 46 that forms the end face 4a and opens and closes the first outlet annular groove 25, and a small diameter portion 47 that connects the first land portion 48 and the second land portion 46.

[0085] Furthermore, in the above embodiment, a spool 9 is used to switch whether or not to regenerate the fluid, but it is also possible to configure the system so that regeneration is always performed, as shown in FIG.

[0086] 6, a regeneration annular groove 29 is formed in the housing body 2A between the second intermediate annular groove 24 and the second outlet annular groove 26. Furthermore, a land portion 56 is provided in the second small diameter portion 52 of the second spool 5, and is located between the regeneration annular groove 29 and the second outlet annular groove 26. The upstream end of the regeneration passage 17 is connected to the regeneration annular groove 29. When the second spool 5 moves toward the first spool 4, the second intermediate annular groove 24 communicates with the regeneration annular groove 29, and the second intermediate annular groove 24 also communicates with the second outlet annular groove 26 via the regeneration annular groove 29.

[0087] Furthermore, as shown in FIG. 7, the recess direction of the recess 28 may be a direction oblique to the plane P on the load check valve 8A side when viewed from the center of the specific spool hole 20A.

[0088] Furthermore, the load check valve 8A may be omitted. Regardless of the presence or absence of the load check valve 8A, the third pilot passage 6c is configured to flow in the specific direction and in a direction perpendicular to the axial direction of the separated type spool 3A (i.e., as shown in FIG. 2 or FIG. 6 If the bridge passage 13 is positioned on the opposite side of the center of the specific spool hole 20A in the left-right direction of the housing 2, the effect of avoiding the passages formed within the housing 2 from becoming complicated can be obtained, as in the above embodiment.

[0089] (summary) The present disclosure provides a hydraulic actuator comprising: a plurality of spools for a plurality of hydraulic actuators that are bidirectionally actuated by the supply of fluid; and a housing including a plurality of spool holes into which the plurality of spools are inserted, a pump passage, a tank passage, and a first supply / discharge passage and a second supply / discharge passage for each of the plurality of spools, wherein at least one of the plurality of spools is a spaced-apart spool including a first spool and a second spool that are spaced apart from each other in the axial direction, the plurality of spool holes including a specific spool hole into which the spaced-apart spool is inserted, and the first spool either blocks the first supply / discharge passage from both the pump passage and the tank passage or blocks the first supply / discharge passage from the pump passage. the second spool either connects the second supply / discharge passage to the pump passage or to one of the tank passages, the second spool either blocks the second supply / discharge passage from both the pump passage and the tank passage or connects the second supply / discharge passage to the other of the pump passage and the tank passage, the housing includes a first pilot chamber facing an end face of the first spool opposite to the second spool and a second pilot chamber facing an end face of the second spool opposite to the first spool, a portion of the specific spool hole between the first spool and the second spool constitutes a third pilot chamber, and the housing includes a pilot passage communicating with the third pilot chamber.

[0090] According to the above configuration, two spools, the first spool and the second spool, can be used to operate the hydraulic actuator connected to the first supply / discharge passage and the second supply / discharge passage in both directions. Furthermore, because the first spool and the second spool are independent of each other, the first spool can be moved according to the pressure difference between the first pilot chamber and the third pilot chamber, and the second spool can be moved according to the pressure difference between the second pilot chamber and the third pilot chamber. This allows independent metering control on the meter-in side and the meter-out side regardless of the direction in which the hydraulic actuator operates. Furthermore, because the number of pilot chambers is three, the number of required solenoid proportional valves can be reduced to three. In other words, independent metering control is possible using three solenoid proportional valves for one hydraulic actuator.

[0091] The plurality of spools may be aligned in a specific direction, and the opening of the pilot passage corresponding to the third pilot chamber may be located in a plane perpendicular to the specific direction and away from a plane passing through the center of the specific spool hole in the specific direction. With this configuration, the opening of the pilot passage corresponding to the third pilot chamber is offset from the center of the specific spool hole in the specific direction, thereby improving the degree of freedom in designing the area around the specific spool hole.

[0092] The housing may include a recess that is recessed so as to point radially outward from the specific spool hole, and the pilot passage may be connected to the recess. With this configuration, the connection position between the third pilot chamber and the pilot passage can be set at any position. In particular, if the opening of the pilot passage is offset from the center of the specific spool hole in a specific direction in which the spools are aligned, the recess can significantly offset the opening of the pilot passage.

[0093] The fluid control device may further include a load check valve provided in the housing for opening and closing the connecting hole to the bridge passage, and the pilot passage may be located on the opposite side of the pump passage from the load check valve in a direction perpendicular to the specific direction and the axial direction of the spaced-type spool. According to this configuration, the pilot passage is located on the opposite side of the pump passage from the load check valve, thereby avoiding the need for complex passages within the housing.

[0094] The housing may include a regeneration passage located on the opposite side of the specific spool hole from the load check valve, the regeneration passage for guiding fluid flowing into the specific spool hole from one of the first supply / discharge passage and the second supply / discharge passage to the other of the first supply / discharge passage and the second supply / discharge passage, and the pilot passage may overlap with the regeneration passage when viewed from the specific direction. With this configuration, the regeneration passage and the pilot passage can be formed on the opposite side of the specific spool hole from the load check valve.

[0095] For example, the above-described fluid control device may include an electromagnetic proportional valve attached to the housing at a position opposite the load check valve with respect to the specific spool hole, and which outputs secondary pressure to the third pilot chamber through the pilot passage.

[0096] For example, the above-mentioned fluid control device may include an electromagnetic proportional valve attached to the housing that outputs secondary pressure to the third pilot chamber through the pilot passage, and the electromagnetic proportional valve may be located on a plane that is perpendicular to the specific direction and passes through the center of the specific spool hole.

[0097] For example, the above-mentioned fluid control device may include an electromagnetic proportional valve attached to the housing that outputs secondary pressure to the third pilot chamber through the pilot passage, and the electromagnetic proportional valve may be located at a position away from the specific direction with respect to a plane that is perpendicular to the specific direction and passes through the center of the specific spool hole.

[0098] The plurality of spools may include a plurality of spaced-apart spools and an integral spool located between the spaced-apart spools and spanning the first and second supply / discharge passages. If the spaced-apart spools are adjacent to each other, three pilot passages and three electromagnetic proportional valves are required for each spaced-apart spool, which means that the pilot passages and electromagnetic proportional valves must be closely spaced. However, if an integral spool is located between the spaced-apart spools, the need for such closely spaced arrangement of the pilot passages and electromagnetic proportional valves can be alleviated.

[0099] The plurality of spools may be aligned in a specific direction, the pump passage may extend in the specific direction, the housing may include a bridge passage that surrounds the pump passage together with the specific spool hole and is connected to the specific spool hole on both sides of the third pilot chamber, and a communication hole that communicates the bridge passage with the pump passage, and the pilot passage may be located on the opposite side of the bridge passage with respect to the center of the specific spool hole in a direction perpendicular to the specific direction and the axial direction of the spaced-type spool. With this configuration, because the pilot passage is located on the opposite side of the bridge passage with respect to the center of the specific spool hole, it is possible to avoid the passages formed in the housing from becoming complicated. [Explanation of symbols]

[0100] 1 Fluid control device 10d Hydraulic Actuator 11 Pump passage 12 Communication hole 13 Bridge Passage 14 1st supply / discharge passage 15 2nd supply / drain passage 16 Tank passage 17 Regeneration passage 2. Housing 20 spool holes 20A specific spool hole 20B normal spool hole 28 depression 3 spools 3A spaced spool 3B integrated spool 4. First spool 4a,4b end face 5. 2 spool 5a,5b end face 61~65 Solenoid proportional valve 6a~6c Pilot passage 7A No. 1 Pilot Room 7B Second Pilot Room 7C 3rd Pilot Room 8A, 8C Load check valve

Claims

1. a plurality of spools for a plurality of hydraulic actuators that are actuated bidirectionally by a supply of fluid; a housing including a plurality of spool holes into which the plurality of spools are respectively inserted, a pump passage, a tank passage, and first and second supply and discharge passages for each of the plurality of spools, At least one of the plurality of spools is a spaced-apart spool including a first spool and a second spool spaced apart from each other in the axial direction, the plurality of spool holes include a specific spool hole into which the spaced-apart spool is inserted, the first spool either disconnects the first supply / discharge passage from both the pump passage and the tank passage or connects the first supply / discharge passage to either the pump passage or the tank passage; the second spool either disconnects the second supply / discharge passage from both the pump passage and the tank passage or connects the second supply / discharge passage to the other of the pump passage and the tank passage; the housing includes a first pilot chamber facing an end surface of the first spool opposite to the second spool, and a second pilot chamber facing an end surface of the second spool opposite to the first spool, a portion of the specific spool hole between the first spool and the second spool constitutes a third pilot chamber; The fluid control device wherein the housing includes a pilot passage communicating with the third pilot chamber.

2. The plurality of spools are arranged in a specific direction, 2. The fluid control device according to claim 1, wherein an opening of the pilot passage to the third pilot chamber is located in a position away from a plane that is perpendicular to the specific direction and passes through a center of the specific spool hole in the specific direction.

3. 3. The fluid control device according to claim 1, wherein the housing includes a recess that is recessed so as to be pointed radially outward from the specific spool hole, and the pilot passage is connected to the recess.

4. The plurality of spools are arranged in a specific direction, the pump passage extends in the specific direction; the housing includes a bridge passage that surrounds the pump passage together with the specific spool hole and is connected to the specific spool hole on both sides of the third pilot chamber, and a communication hole that communicates the bridge passage with the pump passage, a load check valve provided in the housing for opening and closing the opening of the communication hole relative to the bridge passage; 4. The fluid control device according to claim 1, wherein the pilot passage is located on an opposite side of the pump passage from the load check valve in a direction perpendicular to the specific direction and the axial direction of the spaced-type spool.

5. the housing includes a regeneration passage located on the opposite side of the specific spool hole from the load check valve, the regeneration passage being for guiding fluid flowing into the specific spool hole from one of the first supply / discharge passage and the second supply / discharge passage to the other of the first supply / discharge passage and the second supply / discharge passage; The fluid control device according to claim 4 , wherein the pilot passage overlaps with the regeneration passage when viewed from the specific direction.

6. 6. The fluid control device according to claim 4, further comprising an electromagnetic proportional valve attached to the housing at a position opposite to the load check valve with respect to the specific spool hole, the electromagnetic proportional valve outputting a secondary pressure to the third pilot chamber through the pilot passage.

7. a proportional solenoid valve attached to the housing and configured to output a secondary pressure to the third pilot chamber through the pilot passage; The plurality of spools are arranged in a specific direction, 7. The fluid control device according to claim 1, wherein the electromagnetic proportional valve is positioned on a plane perpendicular to the specific direction and passing through a center of the specific spool hole.

8. a proportional solenoid valve attached to the housing and configured to output a secondary pressure to the third pilot chamber through the pilot passage; The plurality of spools are arranged in a specific direction, The fluid control device according to any one of claims 1 to 6, wherein the electromagnetic proportional valve is located at a position away from a plane perpendicular to the specific direction and passing through a center of the specific spool hole in the specific direction.

9. The fluid control device according to any one of claims 1 to 8, wherein the plurality of spools include a plurality of the spaced-apart spools and an integrated spool positioned between the spaced-apart spools and spanning the first supply / discharge passage and the second supply / discharge passage.

10. The plurality of spools are arranged in a specific direction, the pump passage extends in the specific direction; the housing includes a bridge passage that surrounds the pump passage together with the specific spool hole and is connected to the specific spool hole on both sides of the third pilot chamber, and a communication hole that communicates the bridge passage with the pump passage, 4. The fluid control device according to claim 1, wherein the pilot passage is located on the opposite side of the bridge passage with respect to the center of the specific spool hole in a direction perpendicular to the specific direction and the axial direction of the spaced-type spool.

Images