Pilot Cap Unit

Abstract

To prevent malfunction of an unused control valve.SOLUTION: A pilot cap unit 100 attached to a control valve 10 is attached to a valve housing 30 so as to face one end of a spool hole 31, and includes first and second pilot caps 40, 60 partitioning a pilot chamber 11 between the valve housing 30 and them. The first and the second pilot caps 40, 60 include: communication passages (a communication passage 47, a passage 62, a detection passage 63) opened to the pilot chamber 11 and outer surfaces 40a, 60a of the first and the second pilot caps 40, 60 and linearly extending; first and second plugs 50, 65 for sealing openings of the outer surfaces 40a, 60a of the first and the second pilot caps 40, 60 in the passages; and first and second spacers 58, 66 inserted into the communication passages and brought into contact with a spool 25 and the first and the second plugs 50, 65 so as to regulate movement of the spool 25 in a contracting direction of the pilot chamber 11.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a pilot cap unit. [Background technology]

[0002] Patent Document 1 discloses a control valve equipped with a cap. The cap includes a pilot cap attached to a valve housing incorporating a spool and defining a pilot chamber together with the valve housing, and an electromagnetic proportional valve attached to the pilot cap and controlling the pressure of the working fluid supplied to the pilot chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-190635 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the control valve described in Patent Document 1, some of the control valves may be unused depending on the usage method of the user. In the control valve described in Patent Document 1, there is a risk that the working fluid discharged from the pump leaks into the unused pilot chamber through the gap between the inner peripheral surface of the sliding hole in which the unused spool slides and the outer peripheral surface of the unused spool. In this case, the unused spool moves, causing the unused control valve to malfunction.

[0005] The present invention has been made in consideration of the above problems, and has an object to prevent malfunction of an unused control valve. [Means for solving the problem]

[0006] The present invention provides a pilot cap unit that is attached to a control valve having a valve housing with a spool hole formed therethrough and in which a spool is slidably housed, the pilot cap being attached to the valve housing so as to face one end of the spool hole and defining a pilot chamber between the valve housing and the pilot cap, the pilot cap having a linearly extending communication passage that opens to the pilot chamber and an outer surface of the pilot cap, a sealing member that seals the opening of the outer surface of the pilot cap in the communication passage, and a rod-shaped restricting member that is inserted into the communication passage and abuts against the spool and the sealing member to restrict movement of the spool in a direction in which the pilot chamber contracts. The restricting member restricts the movement of the spool so that the spool does not move from the neutral position. It is characterized by:

[0007] In this invention, a restricting member is provided in the communication passage to restrict movement of the spool in the direction in which the pilot chamber contracts. Therefore, even if working fluid leaks into the pilot chamber of an unused control valve, the restricting member prevents the spool from moving due to the pressure of the leaked working fluid. Therefore, malfunction of the unused control valve is prevented.

[0008] The present invention is also characterized in that it further comprises a solenoid valve attached to the pilot cap and controlling the pressure of the pilot fluid supplied to the pilot chamber, and the communication passage communicates between the solenoid valve and the pilot chamber.

[0009] In this invention, the communication passage that guides the pilot fluid from the solenoid valve to the pilot chamber is used as the space for providing the restriction member, so there is no need to provide a dedicated passage for providing the restriction member.

[0010] In addition, the present invention is characterized in that the communication passage is a detection passage that can communicate between the pilot chamber and a pressure sensor that detects the pressure in the pilot chamber, and a sealing member is attached to the opening of the detection passage instead of the pressure sensor.

[0011] In this invention, the detection passage that communicates between the pressure sensor and the pilot chamber is used as the space for providing the restricting member, so there is no need to provide a dedicated passage for the restricting member. Therefore, by simply replacing the sealing member with the pressure sensor and providing the restricting member in the detection passage, it is possible to prevent the spool from moving due to the pressure of the leaked working fluid.

[0012] The present invention also includes a first pilot cap as a pilot cap that defines a first pilot chamber as a pilot chamber between itself and the valve housing, and a second pilot cap that is attached to the valve housing so as to face the other end of the spool hole and defines a second pilot chamber between itself and the valve housing, the valve housing having a first port that opens to the spool hole, is located adjacent to the first pilot chamber and communicates with the atmosphere, and a second port that opens to the spool hole, is located adjacent to the second pilot chamber and has a higher pressure than the first port, and at least the first pilot cap is provided with a regulating member.

[0013] In this invention, a first port communicating with the atmosphere is adjacent to the first pilot chamber, and a second port having a higher pressure than the first port is adjacent to the second pilot chamber. Since the first port is connected to the atmosphere, pressure is unlikely to build up in the first pilot chamber, but since the second port has a higher pressure than the first port, pressure is more likely to build up in the second pilot chamber than in the first pilot chamber. Therefore, if working fluid leaks out through the gap between the inner circumferential surface of the spool hole and the outer circumferential surface of the spool, pressure is more likely to build up in the second pilot chamber than in the first pilot chamber. However, the restricting member can prevent the spool from moving due to the pressure in the second pilot chamber. Effect of the Invention

[0014] According to the present invention, the malfunction of an unused control valve is prevented. [Brief description of the drawings]

[0015] [Figure 1]FIG. 2 is a fluid pressure circuit diagram of a fluid pressure control device including a control valve. [Diagram 2] 1 is a plan view of a first pilot cap of a pilot cap unit according to an embodiment of the present invention. FIG. [Diagram 3] FIG. 3 is a side view of the first pilot cap as viewed from a direction III in FIG. 2. [Figure 4] FIG. 2 is a cross-sectional view showing a pilot cap unit and a control valve according to an embodiment of the present invention. [Diagram 5] FIG. 4 is an enlarged cross-sectional view showing a pilot cap unit according to a first modified example of the present invention. [Figure 6] FIG. 11 is an enlarged cross-sectional view showing a pilot cap unit according to a second modified example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A first pilot cap unit 100a and a second pilot cap unit 100b according to an embodiment of the present invention will be described with reference to the drawings. Hereinafter, the first pilot cap unit 100a and the second pilot cap unit 100b will be collectively referred to simply as "pilot cap unit 100".

[0017] The pilot cap unit 100 and the control valve 10 including the same are provided in a fluid pressure control device 1. The fluid pressure control device 1 is a device that controls an actuator driven by a working fluid discharged from a pump, and is mounted on a work machine such as a construction machine, an agricultural machine, an industrial machine, etc. The following describes a case where the fluid pressure control device 1 is mounted on a hydraulic excavator and used to control the operation of actuators such as a hydraulic motor for traveling and a hydraulic cylinder for driving a boom, an arm, a bucket, etc. Note that, although an example in which hydraulic oil is used as the working fluid to drive the actuator of a hydraulic excavator will be described, other fluids such as working water may be used as the working fluid.

[0018] First, the hydraulic circuit of the fluid pressure control device 1 will be described with reference to Fig. 1. The fluid pressure control device 1 includes a hydraulic pump 3, a hydraulic cylinder 6 as an actuator driven by hydraulic oil discharged from the hydraulic pump 3, a supply passage 20 that supplies the hydraulic oil discharged from the hydraulic pump 3, and a control valve 10 that is provided in the supply passage 20 and controls the flow of the hydraulic oil supplied to and discharged from the hydraulic cylinder 6. A plurality of hydraulic cylinders 6 and control valves 10 are provided, and Fig. 1 shows one hydraulic cylinder 6 and two control valves 10 as representatives.

[0019] The hydraulic pump 3 is driven by an engine mounted on the hydraulic excavator. The hydraulic pump 3 is not limited to this and may be driven by an electric motor. The hydraulic oil discharged from the hydraulic pump 3 is guided to the control valve 10 by a supply passage 20. The hydraulic oil is supplied to and discharged from the rod side chamber 6a and the bottom side chamber 6b of the hydraulic cylinder 6 through a pair of actuator passages 21. Depending on the position of the control valve 10, one of the pair of actuator passages 21 is connected to the supply passage 20 and the other is connected to a tank passage 22 communicating with the tank 4.

[0020] The control valve 10 is a 4-port 3-position spool valve, and in this embodiment, a plurality of control valves 10 having a similar configuration are provided corresponding to each hydraulic cylinder 6. The control valve 10 switches its position by introducing pilot pressure to a pair of pilot chambers 11 through a pilot passage 16 in accordance with the direction and amount of operation of an operating lever 9 by an operator. The control valve 10 switches its position among a neutral position 10A, an extension position 10B, and a retraction position 10C in accordance with the magnitude of the pilot pressure supplied to the pair of pilot chambers 11.

[0021] Specifically, the pilot passage 16 is provided with an electromagnetic proportional pressure reducing valve 7 as a solenoid valve that generates pilot pressure by reducing the discharge pressure of the pilot pump 5. The electromagnetic proportional pressure reducing valve 7 is electrically connected to a controller 8 and generates pilot pressure in response to a signal from the controller 8. The controller 8 transmits a control signal corresponding to the operation direction and operation amount of an operating lever 9 to the electromagnetic proportional pressure reducing valve 7, thereby controlling the electromagnetic proportional pressure reducing valve 7. As a result, the control valve 10 is switched to a neutral position 10A, an extension position 10B, and a contraction position 10C, and hydraulic oil is supplied to and discharged from the rod side chamber 6a and the bottom side chamber 6b of the hydraulic cylinder 6.

[0022] Next, the configurations of the pilot cap unit 100 and the control valve 10 will be described in detail. Fig. 2 is a plan view of the first pilot cap 40 of the first pilot cap unit 100a, Fig. 3 is a side view of the first pilot cap 40 as viewed from the direction III in Fig. 2, and Fig. 4 is a cross-sectional view of the control valve 10. In Figs. 2 and 3, the valve housing 30 and the spool 25 to which the pilot cap unit 100 is attached are indicated by two-dot chain lines.

[0023] The pilot cap unit 100 is attached to the valve housing 30 of the control valve 10. In this embodiment, the multiple control valves 10 have a common valve housing 30. The first pilot cap unit 100a and the second pilot cap unit 100b are each attached to the valve housing 30 and provided across the multiple control valves 10. Since the multiple control valves 10 each have the same configuration, the configuration of one control valve 10 will be described below as a representative example.

[0024] As shown in Figs. 2 to 4, the first pilot cap unit 100a includes a first pilot cap 40 attached to the valve housing 30 so as to face one end of the spool hole 31, and a first electromagnetic proportional pressure reducing valve 7a attached to the first pilot cap 40 and controlling the pressure of pilot pressure oil as a pilot fluid supplied to the first pilot chamber 11a. The first pilot chamber 11a is formed by attaching the first pilot cap unit 100a to the valve housing 30. The second pilot cap unit 100b includes a second pilot cap 60 (see Fig. 4) attached to the valve housing 30 so as to face the other end of the spool hole 31, and a second electromagnetic proportional pressure reducing valve 7b (see Fig. 4) attached to the second pilot cap 60 and controlling the pressure of pilot pressure oil supplied to the second pilot chamber 11b. The second pilot cap unit 100b is attached to the valve housing 30 so as to form the second pilot chamber 11b.

[0025] 3 and 4, the control valve 10 has a rectangular parallelepiped valve housing 30 and a spool 25 slidably assembled in the valve housing 30. A spool hole 31 in which the spool 25 is slidably accommodated is formed penetrating the valve housing 30. The spool 25 has a main body portion 25a accommodated in the spool hole 31, and a spool end 25b connected to one end of the spool 25 and extending into the first pilot chamber 11a. A pair of spring receiving members 52 slidable along the outer periphery of the spool end 25b are accommodated in the first pilot chamber 11a, and a spring 51 serving as a biasing member is interposed between the pair of spring receiving members 52.

[0026] As shown in FIG. 4, the valve housing 30 has a supply port 32 communicating with the supply passage 20, an actuator port 33 communicating with the actuator passage 21, an outlet passage 34 communicating with the supply port 32 and directing the hydraulic oil supplied from the supply port 32 to the actuator port 33, an outlet port 35 communicating with the outlet passage 34, a tank port 36 serving as a second port communicating with the tank passage 22, a drain passage (not shown) communicating with the tank 4, a drain port 37 serving as a first port communicating with the drain passage, and a neutral port 38 communicating with a neutral passage (not shown) and directing the hydraulic fluid to the downstream control valve 10.

[0027] The actuator port 33, the outlet port 35, the tank port 36, the drain port 37, and the neutral port 38 open to the spool hole 31. Two actuator ports 33, two outlet ports 35, and two tank ports 36 are provided symmetrically on the left and right. Three neutral ports 38 are provided near the center of the axial direction of the spool hole 31. In the following, the actuator port 33, the outlet port 35, and the tank port 36 will be described by adding "a" to the reference numerals of the ports provided to the right of the neutral port 38 in FIG. 4, and adding "b" to the reference numerals of the ports provided to the left of the neutral port 38. In addition, with regard to the three neutral ports 38, the one provided in the center in FIG. 4 will be referred to as the neutral port 38a, the one provided on the right side as the neutral port 38b, and the one provided on the left side as the neutral port 38c.

[0028] In the spool hole 31, from the right side in FIG. 4, the drain port 37, the tank port 36a, the actuator port 33a, the lead-out port 35a, the neutral port 38b, the neutral port 38a, the neutral port 38c, the lead-out port 35b, the actuator port 33b, and the tank port 36b open in this order. The drain port 37 is provided adjacent to the first pilot chamber 11a. Here, "the drain port 37 is adjacent to the first pilot chamber 11a" means that no other port is provided between the drain port 37 and the first pilot chamber 11a. The tank port 36b is provided adjacent to the second pilot chamber 11b. In other words, no other port is provided between the tank port 36b and the second pilot chamber 11b. A sub-spool 39 is provided in the lead-out passage 34.

[0029] 4, when pilot pressure is not being introduced to any of the pilot chambers 11, the spool 25 is in the neutral position due to the biasing force of the spring 51, and communication between the outlet port 35a and the actuator port 33a, between the actuator port 33a and the tank port 36a, between the outlet port 35b and the actuator port 33b, and between the actuator port 33b and the tank port 36b is all blocked by the spool 25. In addition, the neutral port 38a communicates with the neutral port 38b and the neutral port 38c, and the hydraulic oil introduced from the upstream control valve 10 to the neutral port 38a is introduced to the downstream control valve 10 via the neutral port 38b and the neutral port 38c.

[0030] When pilot pressure is introduced to the first pilot chamber 11a and the spool 25 moves leftward from the state shown in FIG. 4, the outlet port 35b communicates with the actuator port 33b, and the outlet passage 34 communicates with the actuator passage 21b on the left side in FIG. 4. In addition, the sub-spool 39 opens due to the pressure of the hydraulic oil introduced from the supply port 32 to the outlet passage 34, and the hydraulic oil from the supply port 32 is supplied to the actuator through the outlet passage 34 and the actuator passage 21b. Meanwhile, the actuator port 33a communicates with the tank port 36a, and the actuator passage 21a on the right side in FIG. 4 communicates with the tank passage 22. As a result, the hydraulic oil is discharged from the actuator to the tank 4 through the actuator passage 21a and the tank passage 22. In addition, the communication between the neutral port 38a and the neutral port 38b and the neutral port 38a and the neutral port 38c is blocked, and the flow of hydraulic oil to the downstream control valve 10 through the neutral passage is blocked.

[0031] When pilot pressure is introduced to the second pilot chamber 11b and the spool 25 moves to the right from the state shown in FIG. 4, the outlet port 35a communicates with the actuator port 33a, and the outlet passage 34 communicates with the actuator passage 21a. The pressure of the hydraulic oil introduced from the supply port 32 to the outlet passage 34 opens the sub-spool 39, and the hydraulic oil from the supply port 32 is supplied to the actuator through the outlet passage 34 and the actuator passage 21a. Meanwhile, the actuator port 33b communicates with the tank port 36b, and the actuator passage 21b communicates with the tank passage 22. As a result, the hydraulic oil is discharged from the actuator to the tank 4 through the actuator passage 21b and the tank passage 22. The communication between the neutral port 38a and the neutral port 38b, and between the neutral port 38a and the neutral port 38c is blocked, and the flow of hydraulic oil to the downstream control valve 10 through the neutral passage is blocked.

[0032] In the following, the axial direction of the spool 25 is also referred to as the Z direction. The multiple spools 25 and the multiple pilot chambers 11 are arranged in a direction perpendicular to the axial direction of the spool 25. For this reason, the arrangement direction of the spools 25 and the pilot chambers 11 is also referred to as the X direction. Furthermore, the direction perpendicular to each of the axial direction of the spool 25 (Z direction) and the arrangement direction of the spools 25 (X direction) is also referred to as the Y direction.

[0033] 2 to 4, the first pilot cap 40 of the first pilot cap unit 100a has a cylindrical tube portion 41 provided coaxially with the spool 25, a spring accommodating hole 42 (see FIGS. 3 and 4) as an accommodating hole that accommodates a spring 51 that biases the spool 25 and defines a first pilot chamber 11a between the valve housing 30, and a protruding end portion 43 that protrudes from the tube portion 41 along the axial direction (Z direction) of the spool 25 to the opposite side to the valve housing 30. The protruding end portion 43 is provided so as to connect the multiple tube portions 41 together (see FIG. 2). The first pilot cap 40 is attached to the side surface 31a of the valve housing 30 by a fastening member such as a bolt.

[0034] 3 and 4, when the first pilot cap 40 is attached to the valve housing 30, a first pilot chamber 11a is defined, to which one end of the spool 25 faces. A spring 51, a spring receiving member 52, and a spool end 25b are housed in the first pilot chamber 11a. Similarly, when the second pilot cap 60 of the second pilot cap unit 100b is attached to the valve housing 30, a second pilot chamber 11b is defined, to which the other end of the spool 25 faces.

[0035] As shown in Figures 3 and 4, the first pilot cap 40 has a cap-side supply port 45 connected to the pilot pump 5 and supplied with pilot pressure oil from the pilot pump 5, a cap-side discharge port 46 that discharges the pilot pressure oil to the tank 4, a discharge passage 48 that guides the pilot pressure oil from the cap-side supply port 45 to the electromagnetic proportional pressure reducing valve 7a, a communication passage 47 that opens to the first pilot chamber 11a (the spring accommodating hole 42) and an outer surface 40a of the first pilot cap 40 and extends linearly, a first plug 50 as a sealing member that seals the opening 40b in the outer surface 40a of the first pilot cap 40 in the communication passage 47, and a cap-side drain passage 49 that guides the pilot pressure oil discharged from the electromagnetic proportional pressure reducing valve 7a to the cap-side discharge port 46.

[0036] The cap side supply port 45 and the cap side exhaust port 46 are provided on the protruding end portion 43 of the first pilot cap 40. In this embodiment, the cap side supply port 45 and the cap side exhaust port 46 are provided side by side on one end face in the longitudinal direction (X direction) of the first pilot cap 40. The cap side supply port 45 and the cap side exhaust port 46 are provided to extend in the X direction.

[0037] 3 and 4, the electromagnetic proportional pressure reducing valve 7a has a valve body (not shown) accommodated in a valve body accommodating hole 55, a solenoid 56 that applies a thrust to the valve body, and a spring (not shown) that applies a biasing force to the valve body in a direction counter to the thrust of the solenoid 56. The electromagnetic proportional pressure reducing valve 7a controls the pilot pressure supplied to the first pilot chamber 11a in accordance with a control current supplied to the solenoid 56. In this embodiment, the electromagnetic proportional pressure reducing valve 7a is a direct proportional pressure reducing valve that increases the pilot pressure as the current supplied to the solenoid 56 increases.

[0038] The outlet passage 48 communicates with the cap side supply port 45 and the valve body accommodating hole 55, and is formed linearly between the valve body accommodating hole 55 and the outer surface 40a of the first pilot cap 40. An opening of the outlet passage 48 in the outer surface 40a of the first pilot cap 40 is sealed by a plug 53. The communication passage 47 passes through the valve body accommodating hole 55 and is formed linearly between the first pilot chamber 11a and the outer surface 40a of the first pilot cap 40. A plurality of outlet passages 48 and communication passages 47 are provided corresponding to each electromagnetic proportional pressure reducing valve 7a. The plurality of communication passages 47 each communicate with the cap side supply port 45. The pilot pressure oil guided from the cap side supply port 45 to the valve body accommodating hole 55 through the outlet passage 48 is reduced in pressure by the electromagnetic proportional pressure reducing valve 7a, and is guided to the first pilot chamber 11a through the communication passage 47. In this way, the communication passage 47 communicates between the electromagnetic proportional pressure reducing valve 7a and the first pilot chamber 11a, and constitutes a part of the pilot passage.

[0039] A plurality of cap side drain passages 49 are provided corresponding to each electromagnetic proportional pressure reducing valve 7a. The cap side drain passages 49 communicate between the cap side discharge port 46 and the valve body receiving hole 55.

[0040] As shown in FIG. 4, the first pilot cap 40 has a first spacer 58 as a restricting member that is inserted into the communication passage 47. Note that FIG. 4 shows a cross-sectional view passing through the communication passage 47 and the valve body accommodating hole 55. The first spacer 58 is formed in a rod shape and is provided across the communication passage 47, the valve body accommodating hole 55, and the first pilot chamber 11a. The first spacer 58 is formed separately from the first plug 50, and both ends abut against the spool end 25b of the spool 25 and the first plug 50, respectively. Therefore, the first spacer 58 physically restricts the movement of the spool 25 in the direction in which the first pilot chamber 11a contracts (to the right in FIG. 4).

[0041] 4, the second pilot cap 60 of the second pilot cap unit 100b has a cylindrical tube portion 61 that is provided coaxially with the spool 25, and the tube portion 61 defines a second pilot chamber 11b between the second pilot cap 60 and the valve housing 30. The pilot pressure reduced by the electromagnetic proportional pressure reducing valve 7b is guided to the second pilot chamber 11b through a passage 62. The configuration of the oil passage that guides the pilot pressure from the pilot pump 5 to the second pilot chamber 11b through the electromagnetic proportional pressure reducing valve 7b can be the same as that of the first pilot cap 40, for example, and therefore a detailed description thereof will be omitted.

[0042] Here, in the control valve 10, some of the control valves 10 may be unused depending on the usage method of the user. For example, depending on the construction machine on which the control valve 10 is mounted, the hydraulic cylinder 6 may not be attached to the actuator passage 21 of some of the control valves 10, and the spool 25 may be unused. In such a control valve 10, the hydraulic oil discharged from the hydraulic pump 3 may leak into the pilot chamber 11 through the gap between the inner peripheral surface of the spool hole 31 and the outer peripheral surface of the spool 25. If the unused spool 25 moves due to the pressure of the pilot chamber 11, the unused control valve 10 may malfunction. In addition, if the unused spool 25 moves due to the pressure of the pilot chamber 11, a flow of hydraulic oil occurs in the unused control valve 10, so that the pressure of the hydraulic oil supplied to the control valve 10 in use may decrease, which may adversely affect the operation of the control valve 10 in use.

[0043] In contrast, in the first pilot cap unit 100a of this embodiment, a first spacer 58 is provided in the communication passage 47, and the movement of the spool 25 in the direction in which the first pilot chamber 11a contracts is restricted. Therefore, even if hydraulic oil leaks into the pilot chamber 11 (specifically, the second pilot chamber 11b) of an unused control valve 10, the movement of the spool 25 due to the pressure of the leaked hydraulic oil is prevented by the first spacer 58. Therefore, malfunction of the unused control valve 10 is prevented.

[0044] Here, the drain port 37 is adjacent to the first pilot chamber 11a, and the tank port 36 is adjacent to the second pilot chamber 11b. The drain port 37 is at low pressure (atmospheric pressure) because it is connected to the atmosphere, while the tank port 36 is at a slightly higher pressure than the drain port 37 because it is connected to the tank 4 where pressure is likely to build up. Therefore, if hydraulic oil leaks into the second pilot chamber 11b through the gap between the inner peripheral surface of the spool hole 31 and the outer peripheral surface of the spool 25, pressure is likely to build up in the second pilot chamber 11b. However, the movement of the spool 25 due to the pressure of the second pilot chamber 11b is prevented by the first spacer 58. On the other hand, unlike the tank port 36, the drain port 37 is at atmospheric pressure. Therefore, even if hydraulic oil leaks into the first pilot chamber 11a through the gap between the inner peripheral surface of the spool hole 31 and the outer peripheral surface of the spool 25, the hydraulic oil is easily discharged to the drain port 37, so pressure is unlikely to build up in the first pilot chamber 11a. Therefore, the movement of the spool 25 due to the pressure of the hydraulic oil in the second pilot chamber 11b, which is prone to pressure buildup, is restricted by the first spacer 58, and malfunction of an unused control valve 10 can be prevented simply by restricting the axial movement of the spool 25 to one side.

[0045] Furthermore, in the first pilot cap unit 100a, the first plug 50 and the first spacer 58 are formed separately. This allows the manufacturing cost of the first pilot cap 40 to be reduced compared to the case where a dedicated plug in which the first plug 50 and the first spacer 58 are integrally formed is prepared. Furthermore, when an unused control valve 10 is to be used, it is only necessary to remove the first spacer 58, so that the unused control valve 10 can be easily used. Therefore, the first pilot cap 40 can be shared regardless of the state of use of the control valve 10.

[0046] In addition, in the first pilot cap unit 100a, the communication passage 47 that guides the pilot pressure oil from the electromagnetic proportional pressure reducing valve 7a to the first pilot chamber 11a is used as a space for providing the first spacer 58, so there is no need to provide a dedicated passage for providing the first spacer 58. This reduces the manufacturing cost of the first pilot cap 40.

[0047] According to the above-described embodiment, the following advantageous effects are obtained.

[0048] In the first pilot cap unit 100a, a first spacer 58 is provided in the communication passage 47, and the movement of the spool 25 in the direction in which the first pilot chamber 11a contracts is restricted. Therefore, even if hydraulic oil leaks into the pilot chamber 11 (specifically, the second pilot chamber 11b) of an unused control valve 10, the first spacer 58 prevents the spool 25 from moving due to the pressure of the leaked hydraulic oil. Therefore, malfunction of the unused control valve 10 is prevented. In addition, since the first plug 50 and the first spacer 58 are formed separately, the manufacturing cost of the first pilot cap 40 can be reduced, and the unused control valve 10 can be easily used by simply removing the first spacer 58.

[0049] The following modified examples are also within the scope of the present invention, and it is possible to combine the configurations shown in the modified examples with the configurations described in the above-mentioned embodiments, or to combine the configurations described in the different modified examples below.

[0050] <Variation 1> In the above embodiment, only the first pilot cap 40 of the first pilot cap unit 100a has a first spacer 58 that restricts movement of the spool 25. However, without being limited to this, as shown in Fig. 5, the second pilot cap 60 of the second pilot cap unit 100b may have a second spacer 66 that restricts movement of the spool 25 in the direction in which the second pilot chamber 11b contracts.

[0051] Specifically, the second pilot cap 60 has a detection passage 63 that can communicate between the second pilot chamber 11b and a pressure sensor (not shown) that detects the pressure of the second pilot chamber 11b, a second plug 65 as a sealing member that seals an opening 60b of the outer surface 60a of the second pilot cap 60 in the detection passage 63, and a second spacer 66 as a restricting member provided in the detection passage 63. The detection passage 63 is formed to open to the second pilot chamber 11b and the outer surface 60a of the second pilot cap 60 and extends linearly. The second plug 65 is attached to the opening 60b of the detection passage 63 in place of a pressure sensor. The second spacer 66 is formed in a rod shape and provided across the detection passage 63 and the second pilot chamber 11b. The second spacer 66 is formed separately from the second plug 65 and abuts against the spool 25 and the second plug 65. Therefore, the second spacer 66 physically restricts the movement of the spool 25 in the direction in which the second pilot chamber 11b contracts (to the left in FIG. 5). As a result, the first spacer 58 and the second spacer 66 restrict the movement of the spool 25 to both sides in the axial direction, so that the movement of the unused spool 25 is more reliably prevented. In addition, since the detection passage 63 is used as a space for providing the second spacer 66, it is not necessary to provide a dedicated passage for providing the second spacer 66, so the manufacturing cost of the second pilot cap 60 is reduced. In addition, by simply replacing the second plug 65 with a pressure sensor and providing the second spacer 66 in the detection passage 63, the movement of the spool 25 due to the pressure of the leaked working fluid can be prevented.

[0052] Also, the detection passage 63 may be provided in the first pilot cap unit 100a. In this case, the detection passage 63 of the first pilot cap 40 is formed as a communication passage that opens to the first pilot chamber 11a and the outer surface 40a of the first pilot cap 40 and extends linearly, and communicates the pressure sensor that detects the pressure of the first pilot chamber 11a with the first pilot chamber 11a to guide the working fluid to the pressure sensor. Also, when the detection passage 63 is formed in the first pilot cap 40, a first plug 50 as a sealing member seals the opening 40b of the outer surface 40a of the first pilot cap 40 in the detection passage 63, and a first spacer 58 as a regulating member is provided in the detection passage 63 to regulate the movement of the spool 25 in the direction in which the first pilot chamber 11a contracts.

[0053] <Variation 2> In the above embodiment, the first spacer 58 is provided in the communication passage 47 that guides the pilot pressure oil from the electromagnetic proportional pressure reducing valve 7a to the first pilot chamber 11a. However, as shown in FIG. 6, the first spacer 58 may be provided in a dedicated passage 59 formed separately from the communication passage 47. In this configuration, the opening 40b on the outer surface 40a of the first pilot cap 40 in the passage 59 is sealed by the first plug 50, and both ends of the first spacer 58 abut against the spool end 25b of the spool 25 and the first plug 50, respectively. This physically restricts the movement of the spool 25 in the direction in which the first pilot chamber 11a contracts. Even with this configuration, the same effects as those of the above embodiment can be achieved.

[0054] Similarly, the second spacer 66 of the first modified example may be provided in a dedicated passage (not shown) that is provided separately from the detection passage 63. The passage is formed to open to the second pilot chamber 11b and the outer surface 60a of the second pilot cap 60 and extend linearly. The second spacer 66 may also be provided in the passage 62 that communicates between the electromagnetic proportional pressure reducing valve 7b and the second pilot chamber 11b. Even with this configuration, the same effects as those of the above embodiment can be achieved.

[0055] <Variation 3> In the above embodiment, the first spacer 58 is formed separately from the first plug 50. However, the first spacer 58 may be formed integrally with the first plug 50 and provided in the communication passage 47. The second spacer 66 of the above modification 1 may be formed integrally with the second plug 65 and provided in the detection passage 63. In this case, the electromagnetic proportional pressure reducing valve 7b is disposed like the electromagnetic proportional pressure reducing valve 7a of the first pilot cap 40, and the opening of the outer surface 60a of the second pilot cap 60 in the passage 62 is sealed by a plug (not shown). Even with this configuration, the same effects as those of the above embodiment can be achieved.

[0056] <Modification 4> In the above embodiment, an example has been described in which a plurality of first pilot chambers 11a and a plurality of electromagnetic proportional pressure reducing valves 7a are provided in the first pilot cap 40, but the present invention is not limited to this. The present invention can also be applied to a case in which a single first pilot chamber 11a and a single electromagnetic proportional pressure reducing valve 7a are provided in the first pilot cap 40.

[0057] <Variation 5> In the above embodiment, an example has been described in which the electromagnetic proportional pressure reducing valve 7 is a direct proportional pressure reducing valve that increases the pilot pressure as the current supplied to the solenoid 56 increases, but the present invention is not limited to this. The electromagnetic proportional pressure reducing valve 7 may be an inverse proportional pressure reducing valve that decreases the pilot pressure as the current supplied to the solenoid 56 increases.

[0058] <Variation 6> In the above embodiment, the electromagnetic proportional pressure reducing valves 7a, 7b are provided in the first pilot cap 40 and the second pilot cap 60, respectively. However, the present invention is not limited to this, and the first pilot cap 40 and the second pilot cap 60 may not be provided with the electromagnetic proportional pressure reducing valves 7a, 7b, and the hydraulic oil with pilot pressure generated outside may be guided to the first pilot cap 40 and the second pilot cap 60.

[0059] The configuration, operation, and effects of the embodiment of the present invention configured as above will be described below.

[0060] A pilot cap unit 100 is attached to a control valve 10 having a valve housing 30 with a spool hole 31 formed therethrough, in which a spool 25 is slidably accommodated. The pilot cap unit 100 is attached to the valve housing 30 so as to face one end of the spool hole 31, and includes pilot caps (first and second pilot caps 40, 60) that define a pilot chamber 11 between the valve housing 30 and the pilot caps (first and second pilot caps 40, 60). The pilot caps (first and second pilot caps 40, 60) are arranged such that the pilot chamber 11 and the outer surfaces 40a, 60a of the pilot caps (first and second pilot caps 40, 60) are in contact with each other. The pilot cap (first and second pilot caps 40, 60) has connecting passages (connecting passage 47, passage 62, detection passage 63) that open to each other and extend linearly, sealing members (first and second plugs 50, 65) that seal the openings 40b, 60b on the outer surfaces 40a, 60a of the pilot caps (first and second pilot caps 40, 60) in the connecting passages (connecting passage 47, passage 62, detection passage 63), and rod-shaped regulating members (first and second spacers 58, 66) that are inserted into the connecting passages (communicating passage 47, passage 62, detection passage 63) and abut against the spool 25 and the sealing members (first and second plugs 50, 65) to regulate the movement of the spool 25 in the direction in which the pilot chamber 11 contracts.

[0061] In this configuration, the restricting members (first and second spacers 58, 66) are provided in the communication passages (communication passage 47, passage 62, detection passage 63) and restrict the movement of the spool 25 in the direction in which the pilot chamber 11 contracts. Therefore, even if the working fluid leaks into the pilot chamber 11 of an unused control valve 10, the restricting members (first and second spacers 58, 66) prevent the spool 25 from moving due to the pressure of the leaked working fluid. Therefore, the unused control valve 10 is prevented from malfunctioning.

[0062] In addition, the pilot cap unit 100 further includes an electromagnetic proportional pressure reducing valve 7 attached to the pilot cap (first and second pilot caps 40, 60) and serving as an electromagnetic valve for controlling the pressure of the pilot fluid supplied to the pilot chamber 11, and a communicating passage (communicating passage 47, passage 62) connects the electromagnetic proportional pressure reducing valve 7 to the pilot chamber 11.

[0063] In this configuration, the communicating passages (communicating passage 47, passage 62) that lead the pilot fluid from the electromagnetic proportional pressure reducing valve 7 to the pilot chamber 11 are used as space for providing the regulating members (first and second spacers 58, 66), so there is no need to provide a dedicated passage for providing the regulating members (first and second spacers 58, 66).

[0064] In addition, in the pilot cap unit 100, the communicating passage is a detection passage 63 that can connect the pilot chamber 11 to a pressure sensor that detects the pressure in the pilot chamber 11, and a sealing member (first and second plugs 50, 65) is attached to the opening 60b of the detection passage 63 instead of a pressure sensor.

[0065] In this configuration, since the detection passage 63 communicating between the pressure sensor and the pilot chamber 11 is used as a space for providing the restricting member (first and second spacers 58, 66), there is no need to provide a dedicated passage for providing the restricting member (first and second spacers 58, 66). Therefore, by simply replacing the sealing member (first and second plugs 50, 65) with the pressure sensor and providing the restricting member (first and second spacers 58, 66) in the detection passage 63, it is possible to prevent the spool 25 from moving due to the pressure of the leaked working fluid.

[0066] The pilot cap unit 100 further includes a first pilot cap 40 that defines a first pilot chamber 11a between itself and the valve housing 30, and a second pilot cap 60 that is attached to the valve housing 30 so as to face the other end of the spool hole 31 and defines a second pilot chamber 11b between itself and the valve housing 30. The valve housing 30 has a drain port 37 as a first port that opens into the spool hole 31, is adjacent to the first pilot chamber 11a, and is connected to the atmosphere, and a tank port 36 as a second port that opens into the spool hole 31, is adjacent to the second pilot chamber 11b, and has a higher pressure than the drain port 37. At least the first pilot cap 40 is provided with a first spacer 58.

[0067] In this configuration, the first pilot chamber 11a is adjacent to the drain port 37 that is in communication with the atmosphere, and the second pilot chamber 11b is adjacent to the tank port 36 that has a higher pressure than the drain port 37. The drain port 37 is in communication with the atmosphere, so pressure is unlikely to build up in the first pilot chamber 11a, but the tank port 36 has a higher pressure than the drain port 37, so pressure is more likely to build up in the second pilot chamber 11b than in the first pilot chamber 11a. Therefore, if the working fluid leaks out through the gap between the inner circumferential surface of the spool hole 31 and the outer circumferential surface of the spool 25, pressure is more likely to build up in the second pilot chamber 11b than in the first pilot chamber 11a. However, the first spacer 58 can prevent the spool 25 from moving due to the pressure in the second pilot chamber 11b.

[0068] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments. [Explanation of symbols]

[0069] 7a, 7b... solenoid proportional pressure reducing valve (solenoid valve), 10... control valve, 11a... first pilot chamber, 11b... second pilot chamber, 30... valve housing, 31... spool hole, 32... spool, 36... tank port (second port), 37... drain port (first port), 40... first pilot cap (pilot cap), 40a... outer surface, 40b... opening, 42... spring accommodating hole (accommodating hole), 47... communication passage, 50... first plug (sealing member), 58... first spacer (regulating member), 60... second pilot cap (pilot cap), 60a... outer surface, 60b... opening, 63... detection passage (communicating passage), 65... second plug (sealing member), 66... ​​second spacer (regulating member), 100a, 100b... pilot cap unit

Claims

1. A pilot cap unit to be attached to a control valve having a valve housing with a spool hole formed therethrough and in which a spool is slidably accommodated, a pilot cap attached to the valve housing so as to face one end of the spool hole, and defining a pilot chamber between the valve housing and the pilot cap; The pilot cap is a communication passage that opens to the pilot chamber and an outer surface of the pilot cap and extends linearly; a sealing member that seals an opening of the communication passage on the outer surface of the pilot cap; a rod-shaped restricting member that is inserted into the communication passage and abuts against the spool and the sealing member to restrict movement of the spool in a direction in which the pilot chamber contracts, The pilot cap unit is characterized in that the regulating member regulates the movement of the spool so that the spool does not move from a neutral position.

2. 2. The pilot cap unit according to claim 1, a solenoid valve attached to the pilot cap for controlling a pressure of the pilot fluid supplied to the pilot chamber; The pilot cap unit is characterized in that the communication passage communicates between the solenoid valve and the pilot chamber.

3. 2. The pilot cap unit according to claim 1, the communication passage is a detection passage that can communicate between the pilot chamber and a pressure sensor that detects the pressure of the pilot chamber, A pilot cap unit, characterized in that the sealing member is attached to the opening of the detection passage in place of the pressure sensor.

4. A pilot cap unit according to any one of claims 1 to 3, a first pilot cap as the pilot cap that defines a first pilot chamber as the pilot chamber between the first pilot cap and the valve housing; a second pilot cap attached to the valve housing so as to face the other end of the spool hole and defining a second pilot chamber between the valve housing and the second pilot cap; the valve housing has a first port that opens to the spool hole, is provided adjacent to the first pilot chamber, and communicates with the atmosphere, and a second port that opens to the spool hole, is provided adjacent to the second pilot chamber, and has a higher pressure than the first port, A pilot cap unit, characterized in that at least the first pilot cap is provided with the regulating member.

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