Control valve and work machine equipped with control valve

Abstract

To provide a control valve which can stably remove air.SOLUTION: A valve control V includes: a valve body 46; a spool hole 47 formed at the valve body; a spool 45 slidably assembled to the spool hole; a pilot room 57 into which a pilot oil for operating the spool is introduced; a discharge passage 51 which discharges a working fluid to the outside of the valve body; a spiral groove 67 which is spirally formed at an outer periphery of the spool and communicates with the discharge passage; and at least one axial groove 72 which is formed along an axial direction of the spool on an inner surface of the spool hole and allows the pilot room and the spiral groove to communicate with each other.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a control valve and a working machine equipped with the control valve.

Background Art

[0002] Conventionally, a control valve disclosed in Patent Document 1 is known. The control valve disclosed in Patent Document 1 includes a valve body in which an actuator port to which a hydraulic actuator can be connected and a discharge passage for discharging the hydraulic oil returning through the actuator port to the outside are formed. A spool hole is formed in the valve body, and a spiral spool groove is formed on the outer periphery of a spool slidably incorporated in the spool hole. A pilot chamber into which pilot oil for operating the spool is introduced is provided. When the spool is moved by a predetermined amount from the neutral position by the pilot oil introduced into the pilot chamber, the pilot chamber and the discharge passage communicate with each other through the spiral groove. Thereby, a part of the pilot oil introduced into the pilot chamber leaks into the discharge passage through the spiral groove, thereby removing the air accumulated in the pilot chamber and improving the switching responsiveness of the spool.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the control valve disclosed in Patent Document 1, it is conceivable that variations occur in the air bleeding amount (the amount of air remaining in the pilot chamber). Specifically, since the spool is rotatable around its axis, for example, when assembling the spool, the position of the end portion on the pilot chamber side (the inlet side end portion of the pilot oil) in the length direction of the spiral groove varies depending on the rotational position of the spool around its axis. Since air accumulates in the upper part of the pilot chamber, for example, when the inlet side end portion of the spiral groove is at a low position, it becomes difficult for the air to escape.

[0005] In view of the above problems, an object of the present invention is to provide a control valve capable of stably bleeding air and a working machine equipped with the control valve.

Means for Solving the Problems

[0006] A control valve according to an aspect of the present invention includes a valve body, a spool hole formed in the valve body, a spool slidably incorporated in the spool hole, a pilot chamber into which pilot oil for operating the spool is introduced, a discharge passage for discharging hydraulic oil to the outside of the valve body, a spiral groove formed spirally on the outer periphery of the spool, at least one axial groove formed on the inner surface of the spool hole along the axial direction of the spool and communicating the pilot chamber with the spiral groove, and a circumferential groove formed circumferentially on the inner surface of the spool hole, the circumferential groove communicating with the axial groove on the side opposite to the end portion on the side communicating with the pilot chamber in the axial groove. The discharge passage is positioned at a distance from the circumferential groove on the side opposite to the axial groove. In a state where the valve body is installed such that the spool extends in the horizontal direction, the pilot chamber is adjacent to the spool hole in the axial direction of the spool, and the axial groove is positioned above the spool. The spiral groove is positioned closer to the pilot chamber side than the axial groove when the spool is in the neutral position. When the spool is moved a predetermined amount from the neutral position by the pilot oil introduced into the pilot chamber, Without passing through the axial groove and the circumferential groove the pilot chamber and the Discharge pathcommunicates with the above and is configured to communicate with the axial groove and the circumferential groove Directly to communicate with each other.

Advantages of the Invention

[0007] In the above control valve, the pilot oil leaks from the spiral groove to the discharge passage through the axial groove, so that the air in the pilot chamber escapes. That is, since the pilot oil leaks from the spiral groove via the axial groove formed in the valve body, the air can be stably discharged regardless of the rotational position of the spool around its axis.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present invention will be described with appropriate reference to the drawings. FIG. 1 is a side view showing the overall configuration of the working machine 1. In this embodiment, a backhoe, which is a swing-type working machine 1, is exemplified. As shown in FIG. 1, the working machine 1 includes a machine body (swing base) 2, a left traveling device 3L disposed on the left side of the machine body 2, a right traveling device 3R disposed on the right side of the machine body 2, and a working device 4 attached to the front portion of the machine body 2. A cabin 5 is mounted on the machine body 2. Inside the cabin 5, a driver's seat for a driver (operator) to sit is provided.

[0010] In this embodiment, the direction in which the driver sitting on the driver's seat 6 of the working machine 1 faces (the direction of arrow A1 in FIG. 1) is defined as the front, and the opposite direction (the direction of arrow A2 in FIG. 1) is defined as the rear. Also, the left side of the driver (the front side in FIG. 1) is defined as the left, and the right side of the driver (the back side in FIG. 1) is defined as the right. Therefore, the direction of K1 in FIG. 1 is the front-rear direction (the machine body front-rear direction). Also, the horizontal direction, which is perpendicular to the front-rear direction K1, is defined as the machine body width direction.

[0011] In this embodiment, the left traveling device 3L and the right traveling device 3R are each configured as a crawler-type traveling device. The left traveling device 3L is driven by a traveling motor ML, and the right traveling device 3R is driven by a traveling motor MR. The traveling motors ML and MR are each constituted by a hydraulic motor (hydraulic actuator AC). A dozer device 7 is attached to the front portion of a traveling frame 11 to which the left traveling device 3L and the right traveling device 3R are attached. The dozer device 7 can be lifted and lowered (raise and lower the blade) by extending and retracting a dozer cylinder C1.

[0012] The machine body 2 is rotatably supported about a vertical axis (an axis extending in the vertical direction) via a swing bearing 8 on a traveling frame 11. The machine body 2 is rotationally driven by a swing motor MT composed of a hydraulic motor (hydraulic actuator AC). The machine body 2 has a swivel base plate 9 that swivels around the vertical axis and a weight supported at the rear of the swivel base plate 9. The swivel base plate 9 is formed of a steel plate or the like and is connected to the swivel bearing 8. A prime mover E1 is mounted at the rear of the machine body 2. The prime mover E1 is an engine. Note that the prime mover E1 may be an electric motor or may be a hybrid type having an engine and an electric motor.

[0013] The machine body 2 has a support bracket 13 at the front. A swing bracket 14 is attached to the support bracket 13 so as to be swingable around the vertical axis. A working device 4 is attached to the swing bracket 14. The working device 4 has a boom 15, an arm 16, and a bucket 17 as a working tool. The base of the boom 15 is pivotally attached to the swing bracket 14 so as to be rotatable around a horizontal axis (an axis extending in the machine width direction) and is swingable in the vertical direction. The base of the arm 16 is pivotally attached to the tip side of the boom 15 so as to be rotatable around a horizontal axis and is swingable in the front-rear direction K1 or the vertical direction. The bucket 17 is provided at the tip side of the arm 16 so as to be capable of performing a crowding operation and a dumping operation. Instead of or in addition to the bucket 17, the working machine 1 can be equipped with other working tools (hydraulic attachments) drivable by a hydraulic actuator AC.

[0014] The swing bracket 14 is swingable by the extension and contraction of a swing cylinder C2 provided in the machine body 2. The boom 15 is swingable by the extension and contraction of a boom cylinder C3. The arm 16 is swingable by the extension and contraction of an arm cylinder C4. The bucket 17 is capable of performing a crowding operation and a dumping operation by the extension and contraction of a bucket cylinder C5 as a working tool cylinder. The dozer cylinder C1, the swing cylinder C2, the boom cylinder C3, the arm cylinder C4, and the bucket cylinder C5 are constituted by hydraulic cylinders (hydraulic actuators AC).

[0015] Figure 2 shows a schematic configuration of a hydraulic system for operating various hydraulic actuators AC (MT, ML, MR, C1 to C5) equipped on the work machine 1 described above. As shown in Figure 2, the hydraulic system includes a control valve CV, a pressure oil supply unit 18, and a flow control unit 19. The control valve CV is configured by arranging (stacking) a plurality of control valves V (V1 to V9) for controlling various hydraulic actuators AC (MT, ML, MR, C1 to C5), an inlet block B1, and an outlet block B2 in one direction, connecting them to each other, and connecting them to each other by internal oil passages.

[0016] The control valve V includes a swing control valve V1 for controlling the swing motor MT, a first travel control valve V2 for controlling the travel motor ML of the left travel device 3L, a second travel control valve V3 for controlling the travel motor MR of the right travel device 3R, a dozer control valve V4 for controlling the dozer cylinder C1, an arm control valve V5 for controlling the arm cylinder C4, a boom control valve V6 for controlling the boom cylinder C3, a bucket control valve V7 for controlling the bucket cylinder C5, and an SP control valve V9 for controlling the hydraulic actuator AC equipped on the hydraulic attachment when the hydraulic attachment is attached as a work tool.

[0017] The pressure oil supply unit 18 is equipped with a first pump (main pump) P1 for supplying operating oil for operating the hydraulic actuators AC (MR, ML, MT, C1 to C5) and a second pump (pilot pump) P2 for supplying signal pressure such as pilot pressure and detection signals. The first pump P1 and the second pump P2 are driven by the prime mover E1. The first pump P1 is a variable displacement hydraulic pump (swash plate type variable displacement axial pump) whose discharge volume can be changed by changing the angle of the swash plate. The discharged oil of the first pump P1 is supplied to the inlet block B1 via the oil passage a, and then supplied to each control valve V (V1 to V9). The second pump P2 (pilot pump) is composed of a fixed displacement gear pump. The discharged oil of the second pump P2 is supplied as a pilot source pressure to the primary side of an operating device that pilot-operates the control valve via the oil passage b.

[0018] The flow rate control unit 19 controls the swash plate of the first pump P1. The swash plate control of the first pump P1 is performed by controlling the pressure acting on the flow rate compensation piston that changes the swash plate angle of the first pump P1 by controlling the flow rate compensation valve provided in the flow rate control unit 19. In the above hydraulic system, a load sensing system is adopted. The load sensing system functions such that when a plurality of the hydraulic actuators AC equipped on the working machine 1 are simultaneously operated, the pressure compensation valve incorporated in the control valve V functions as an adjustment of the load between the hydraulic actuators AC, generating a pressure loss corresponding to the differential pressure from the highest load pressure on the control valve V on the low load pressure side, and enabling a flow rate (distribution) corresponding to the operation amount of the spool of the control valve V to flow regardless of the magnitude of the load.

[0019] Also, the load sensing system can improve power saving and operability by controlling the discharge volume of the hydraulic pump (first pump P1) according to the load pressure of each hydraulic actuator AC equipped on the working machine 1 and discharging the hydraulic power required for the load from the hydraulic pump (first pump P1). The load sensing system has a PLS signal line L1 that transmits the highest load pressure among the load pressures of each control valve V (V1 to V9) as a PLS signal pressure (load signal) to the flow rate control unit 19 (flow rate compensation valve), and a PPS signal line L2 that transmits the discharge pressure of the first pump P1 as a PPS signal pressure to the flow rate control unit (flow rate compensation valve). The signal lines L1 and L2 are led out from the inlet block B1 and connected to the flow rate control unit 19.

[0020] Figure 3 shows a schematic configuration of a hydraulic circuit related to one control valve V. As shown in Figure 3, the control valve V is constituted by a pilot-operated switching valve that is pilot-operated by an operating device 21. The operating device 21 has a pilot valve 21A that outputs a pilot pressure (pilot oil) to the control valve V, and an operating lever 21B that operates the pilot valve 21A.

[0021] The control valve V includes a pressure compensation valve 22. The highest load pressure among the load pressures of each control valve V is transmitted to the pressure compensation valve 22 as a load signal. The control valve V is constituted by a 7-port 3-position switching valve, and is switchable between a neutral position 23, a first switching position 24, and a second switching position 25. The control valve V is held at the neutral position 23 by the biasing forces of a neutral spring 26A on one side in the switching direction and another neutral spring 26B on the other side opposite to the one side, and is switched from the neutral position 23 to the first switching position 24 or the second switching position 25 by the pilot pressure output from the pilot valve 21A.

[0022] The control valve V has a pair of actuator ports 27 (a first actuator port 27a and a second actuator port 27b) connected to a hydraulic actuator AC (in the illustrated example, a hydraulic cylinder) that is the control target. In the illustrated example, the first actuator port 27a communicates with a rod-side oil chamber 29 of the hydraulic actuator AC (hydraulic cylinder) via a first hydraulic pipeline 28a, and the second actuator port 27b communicates with a bottom-side oil chamber 30 of the hydraulic actuator AC (hydraulic cylinder) via a second hydraulic pipeline 28b.

[0023] The control valve V has a pump port 31, an introduction port 32, a discharge port 33, a first import port 34, and a second import port 35. The pump port 31 communicates with the discharge port that discharges the hydraulic oil in the first pump P1 (hydraulic pump). The introduction port 32 is connected to the pressure compensation valve 22 via the introduction pipeline 36. The discharge port 33 communicates with the hydraulic oil tank T1. The first import port 34 is connected to the pressure compensation valve 22 via the first supply pipeline 37 and the derivation pipeline 38. The second import port 35 is connected to the pressure compensation valve 22 via the second supply pipeline 39 and the derivation pipeline 38. A first load check valve 40 is provided in the first supply pipeline 37, and a second load check valve 41 is provided in the second supply pipeline 39. The first load check valve 40 and the second load check valve 41 are check valves that prevent the pressure on the actuator port 27 side from flowing backward.

[0024] The control valve V has a first pressure receiving part 42A on one side in the switching direction and a second pressure receiving part 42B on the other side. The first pressure receiving part 42A is connected to the pilot valve 21A via the first pilot pipeline 43A. The second pressure receiving part 42B is connected to the pilot valve 21A via the second pilot pipeline 43B. Therefore, when the pilot pressure output from the pilot valve 21A by operating the operation lever 21B acts on the first pressure receiving part 42A via the first pilot pipeline 43A, the control valve V is switched from the neutral position 23 to the first switching position 24. Also, when the pilot pressure output from the pilot valve 21A by operating the operation lever 21B acts on the second pressure receiving part 42B via the second pilot pipeline 43B, the control valve V is switched from the neutral position 23 to the second switching position 25.

[0025] At the first switching position 24, the pump port 31 communicates with the introduction port 32 via the throttle 44, and the hydraulic oil from the first pump P1 flows into the first import port 34 via the introduction port 32 → the introduction pipeline 36 → the pressure compensation valve 22 → the derivation pipeline 38 → the first supply pipeline 37. The hydraulic oil flowing into the first import port 34 flows into the rod side oil chamber 29 through the first hydraulic pipeline 28a from the first actuator port 27a. Also, the hydraulic oil flowing out from the bottom side oil chamber 30 flows into the second actuator port 27b via the second hydraulic pipeline 28b, and flows from the second actuator port 27b to the hydraulic oil tank T1 via the discharge port 33.

[0026] At the second switching position 25, the pump port 31 communicates with the introduction port 32 via the throttle 44, and the hydraulic oil from the first pump P1 flows into the second import port 35 via the introduction port 32 → the introduction pipeline 36 → the pressure compensation valve 22 → the derivation pipeline 38 → the second supply pipeline 39. The hydraulic oil flowing into the second import port 35 flows into the bottom side oil chamber 30 through the second hydraulic pipeline 28b from the second actuator port 27b. Also, the hydraulic oil flowing out from the rod side oil chamber 29 flows into the first actuator port 27a via the first hydraulic pipeline 28a, and flows from the first actuator port 27a to the hydraulic oil tank T1 via the discharge port 33.

[0027] Figure 4 shows a cross-sectional view of the control valve V. The cross-sectional view is a cross-section cut along a plane orthogonal to the stacking direction of a plurality of control valves V. As shown in Figure 4, the control valve V is installed on the machine body 2. As shown in Figure 4, the control valve V has a valve body 46 in which a spool 45, a pressure compensation valve 22, etc. are incorporated and an oil passage is formed. The valve body 46 has a spool hole 47 in which the spool 45 is slidably incorporated in the axial direction. The spool hole 47 is formed horizontally through the valve body 46.

[0028] A pair of actuator ports 27 (first actuator port 27a and second actuator port 27b) connected to the hydraulic actuator AC are formed in the valve body 46. Specifically, the pair of actuator ports 27 are formed on the upper surface 46a of the valve body 46 (a surface parallel to the spool hole 47 in the valve body 46). The first actuator port 27a is formed at one end side 48A in the spool axis direction (the axial direction of the spool 45) of the valve body 46, and the second actuator port 27b is formed at the other end side 48B in the spool axis direction of the valve body 46. The first actuator port 27a communicates with the spool hole 47 via the first flow passage 49, and the second actuator port 27b communicates with the spool hole 47 via the second flow passage 50.

[0029] The valve body 46 has a discharge passage 51 for discharging the hydraulic oil returning from the hydraulic actuator AC to the outside through the actuator port 27. Specifically, the discharge passage 51 communicates with the hydraulic oil tank T1 via the discharge port 33. Therefore, the hydraulic oil returning from the hydraulic actuator AC flows to the hydraulic oil tank T1 through the discharge passage 51, the discharge port 33, etc. The discharge passage 51 communicates with the spool hole 47 between one end in the spool axis direction of the valve body 46 and the first flow passage 49, and also communicates with the spool hole 47 between the other end in the spool axis direction of the valve body 46 and the second flow passage 50.

[0030] An introduction port 32 is formed at a substantially central portion in the axial direction of the spool hole 47 in the valve body 46. A pump port 31 is formed at the other end side 48B in the spool axis direction of the introduction port 32 with a space therebetween in the spool axis direction. The pressure compensation valve 22 is provided at a substantially central portion in the spool axial direction of the valve body 46 so as to extend from the introduction port 32 to the upper surface 46a. A block member 52 is fixed by bolts or the like at a position corresponding to the pressure compensation valve 22 on the upper surface 46a of the valve body 46. A load pressure introduction chamber 53 into which the highest load pressure among a plurality of hydraulic actuators AC is introduced is formed in the block member 52. A load signal is introduced from the load pressure introduction chamber 53 to the pressure compensation valve 22.

[0031] A first import port 34 is formed at a position closer to the first flow passage 49 between the introduction port 32 and the first flow passage 49 in the spool hole 47. The hydraulic oil that has flowed from the introduction port 32 through the pressure compensation valve 22 into the lead-out pipe 38 flows through the first supply pipe 37 having the first load check valve 40 into the first import port 34. Also, a second import port 35 is formed at a position closer to the second flow passage 50 between the pump port 31 and the second flow passage 50 in the spool hole 47. The hydraulic oil flowing through the lead-out pipe 38 flows through the second supply pipe 39 having the second load check valve 41 into the second import port 35.

[0032] A pair of first communication grooves 54 for communicating the pump port 31 and the introduction port 32 are formed at a substantially central portion in the axial direction of the spool 45. The first communication grooves 54 are constituted by grooves formed in an annular shape in the circumferential direction on the outer periphery of the spool 45. When the control valve V is in the neutral position 23, the communication between the pump port 31 and the introduction port 32 by the first communication grooves 54 is blocked. When the control valve V is switched from the neutral position 23 to the first switching position 24, one (right side) of the first communication grooves 54 (54a) communicates the pump port 31 and the introduction port 32 through a notch (throttle 44). Also, when the control valve V is switched from the neutral position 23 to the second switching position 25, the other (left side) of the first communication grooves 54 (54b) communicates the pump port 31 and the introduction port 32 through a notch (throttle 44).

[0033] On both sides of the spool 45 in the axial direction, a pair of second communication grooves 55 are formed. The second communication groove 55 is constituted by a groove formed in an annular shape in the circumferential direction on the outer periphery of the spool 45. The second communication groove 55 (55a) on one end side 48A (on the right side in this case) in the spool axial direction is a groove for communicating the first flow passage 49 (the first actuator port 27a) with the first import 34 or for communicating the first flow passage 49 with the discharge passage 51. When the control valve V is in the neutral position 23, the communication between the first flow passage 49 and the first import 34 and the communication between the first flow passage 49 and the discharge passage 51 through one of the second communication grooves 55 (55a) are blocked. When the control valve V is switched from the neutral position 23 to the first switching position 24, one of the second communication grooves 55 (55a) communicates the first flow passage 49 with the first import 34, and when switched to the second switching position 25, one of the second communication grooves 55 (55a) communicates the first flow passage 49 with the discharge passage 51.

[0034] The second communication groove 55 (55b) on the other end side (on the left side in this case) in the spool axial direction is a groove for communicating the second flow passage 50 (the second actuator port 27b) with the second import 35 or for communicating the second flow passage 50 with the discharge passage 51. When the control valve V is in the neutral position 23, the communication between the second flow passage 50 and the second import 35 and the communication between the second flow passage 50 and the discharge passage 51 through the other second communication groove 55 (55b) are blocked. When the control valve V is switched from the neutral position 23 to the first switching position 24, the other second communication groove 55 (55b) communicates the second flow passage 50 with the discharge passage 51, and when switched to the second switching position 25, the other second communication groove 55 communicates the second flow passage 50 with the second import 35.

[0035] On both sides of the spool axis direction in the valve body 46, a pair of spool caps 56 (the first spool cap 56A and the second spool cap 56B) are attached. The first spool cap 56A is a component of the first pressure receiving part 42A and is attached to one end side 48A in the spool axis direction of the valve body 46. The second spool cap 56B is a component of the second pressure receiving part 42B and is attached to the other end side 48B in the spool axis direction of the valve body 46.

[0036] Inside the first spool cap 56A, a substantially cylindrical pilot chamber 57 (the first pilot chamber 57A) into which pilot pressure (pilot oil) is introduced from the first pilot pipeline 43A is formed. The first pilot chamber 57A is arranged adjacent to the spool hole 47 in the spool axis direction (horizontal direction) and communicates with the spool hole 47. A guide part 58 (58A) formed at one end side of the spool 45 is inserted into the first pilot chamber 57A. When pilot oil is introduced into the first pilot chamber 57A, the guide part 58A at one end of the spool 45 is pressed by the pilot oil, and the spool 45 moves to the left in FIG. 4, and the control valve V is switched from the neutral position 23 to the first switching position 24.

[0037] Inside the second spool cap 56B, a substantially cylindrical pilot chamber 57 (the second pilot chamber 57B) into which pilot pressure (pilot oil) is introduced from the second pilot pipeline 43B is formed. The second pilot chamber 57B is arranged adjacent to the spool hole 47 in the spool axis direction (horizontal direction) and communicates with the spool hole 47. A guide part 58 (58B) formed at the other end side of the spool 45 is inserted into the second pilot chamber 57B. When pilot oil is introduced into the second pilot oil chamber, the guide part 58B at the other end of the spool 45 is pressed by the pilot oil, and the spool 45 moves to the right in FIG. 4, and the control valve V is switched from the neutral position 23 to the second switching position 25.

[0038] Note that the amount of movement of the spool 45 can be adjusted according to the pressure of the pilot oil introduced into each pilot chamber 57, and the supply amount of the hydraulic oil to the hydraulic actuator AC can be adjusted. On the side opposite to the spool hole 47 in the first spool cap 56A, a passage hole 59(59A) is formed which is connected to the first pilot pipeline 43A and communicates with the first pilot chamber 57A. A step portion 60A is formed between the passage hole 59A and the first pilot chamber 57A.

[0039] On the side opposite to the spool hole 47 in the second spool cap 56B, a passage hole 59(59B) is formed which is connected to the second pilot pipeline 43B and communicates with the second pilot chamber 57B. A step portion 60B is formed between the passage hole 59B and the second pilot chamber 57B. Since the internal configurations of the pair of spool caps 56 are the same, they will be described together with reference to FIGS. 4, 5, and 6. As shown in FIG. 4, inside the pilot chamber 57 (the first pilot chamber 57A, the second pilot chamber 57B), a pair of spring sheets 61 (the first spring sheet 62, the second spring sheet 63) and neutral springs 26A, 26B interposed between the pair of spring sheets 61 are incorporated.

[0040] As shown in FIG. 5, the first spring sheet 62 has a spring guide 62a, a spring receiving portion 62b, and a cylindrical portion 62c. The spring guide 62a is externally fitted to the guide portion 58 so as to be relatively movable in the spool axis direction. As shown in FIG. 6, a gap is provided between the inner peripheral surface of the spring guide 62a and the outer peripheral surface of the guide portion 58. The spring receiving portion 62b projects radially outward from the valve body 46 side of the spring guide 62a. The cylindrical portion 62c extends from the outer peripheral side of the spring receiving portion 62b toward the valve body 46 and abuts against the valve body 46.

[0041] As shown in FIG. 5, the second spring sheet 63 has a spring guide 63a and a spring receiving portion 63b. The spring guide 63a is formed in a cylindrical shape having an axis extending in the spool axis direction, and is arranged so as to face the guide portion 58 with a space therebetween in the spool axis direction. The spring receiving portion 63b protrudes radially outward from the end portion on the passage hole 59 side of the spring guide 63a and abuts against the stepped portion 60A (60B). The inner hole 63c of the spring guide 63a communicates with the pilot chamber 57 and the passage hole 59, and pilot pressure is introduced from the passage hole 59 into the pilot chamber 57 through the inner hole 63c.

[0042] The neutral springs 26A (26B) are formed by coil springs. One end side is externally fitted to the spring guide 62a of the first spring sheet 62, and the other end side is externally fitted to the spring guide 63a of the second spring sheet 63, and they are interposed in a compressed state between the spring receiving portion 62b and the spring receiving portion 63b. As shown in FIG. 4, a pair of groove forming portions 65 are provided on both sides in the axial direction of the spool 45. One (right side) groove forming portion 65A is adjacent to the guide portion 58A in the spool axis direction on the inner side in the spool axis direction of the guide portion 58A (the direction from the end portion in the spool axis direction of the spool 45 toward the central portion in the spool axis direction of the spool 45). The other (left side) groove forming portion 65B is adjacent to the guide portion 58B in the spool axis direction on the inner side in the spool axis direction of the guide portion 58B. Each groove forming portion 65 is formed to have a larger diameter than the guide portion 58. Therefore, as shown in FIG. 5, a stepped portion 66 is formed between the groove forming portion 65 and the guide portion 58. The spring guide 62a of the first spring sheet 62 abuts against the stepped portion 66.

[0043] As shown in FIG. 5, spiral grooves 67 are formed in each groove forming portion 65 (the outer circumference of the spool 45). The spiral groove 67 is a groove formed in a spiral shape on the outer circumference of the groove forming portion 65 (the spool 45), and is a spiral groove advancing in the spool axis direction. The spiral groove 67 is formed in the groove forming portion 65 from one end side to the other end side in the spool axis direction. On the outer side in the spool axis direction (the direction from the central part in the axial direction of the spool 45 toward the end part in the axial direction of the spool 45) of the groove forming part 65, a tapered surface 65a that gradually narrows as it goes toward the outer side in the spool axis direction is formed.

[0044] On the inner side in the spool axis direction of the groove forming part 65 in the spool 45, an annular groove 68 is formed. The annular groove 68 is formed adjacent to the groove forming part 65 in the spool axis direction. The annular groove 68 is a groove formed annularly in the circumferential direction on the spool 45. The spiral groove 67 is formed from the tapered surface 65a to the annular groove 68. The inner end part 67a in the spool axis direction of the spiral groove 67 communicates with the annular groove 68.

[0045] As shown in FIGS. 5 and 6, on the end part side of the spool hole 47 in the valve body 46, a space part (first space part) 69 formed by a peripheral surface 47a that covers the spiral groove 67 and the annular groove 68 with a gap from the outer periphery is provided. Further, the cylindrical part 62c of the first spring seat 62 covers the spiral groove 67 with a gap from the outer periphery, and a space part (second space part) 70 is formed by the inner peripheral surface 62d of the cylindrical part 62c. The first space part 69 and the second space part 70 communicate with each other. As shown in FIGS. 4 and 5, the land part 71 between the annular groove 68 and the second communication groove 55 in the spool 45 is located on the inner side in the spool axis direction of the groove forming part 65 and is formed adjacent to the groove forming part 65 via the annular groove 68 in the spool axis direction. Further, the land part 71 is formed with the same diameter as the groove forming part 65.

[0046] As shown in FIGS. 5 and 6, in a portion corresponding to the land portion 71 on the inner surface of the spool hole 47, an axial groove 72 formed along the axial direction of the spool 45 and a circumferential groove 73 formed annularly in the circumferential direction are formed on the inner surface of the spool hole 47. In other words, the axial groove 72 and the circumferential groove 73 are formed on both sides in the axial direction of the spool of the inner surface of the spool hole 47 and in the vicinity of the spiral groove 67. Further, the axial groove 72 and the circumferential groove 73 are formed on the inner peripheral surface of a support hole portion 74 that supports the land portion 71 in the spool hole 47. As shown in FIG. 5, a discharge passage 51 intersects the support hole portion 74. The support hole portion has a portion (first portion) 74a on the annular groove 68 side from the discharge passage 51 and a portion (second portion) 74b on the second communication groove 55 side from the discharge passage 51. The axial groove 72 and the circumferential groove 73 are formed in the first portion 74a. In other words, the axial groove 72 and the circumferential groove 73 are formed between the pilot chamber 57 and the discharge passage 51.

[0047] As shown in FIGS. 5 and 6, the axial groove 72 is formed from the end on the annular groove 68 side of the first portion 74a (support hole portion 74) toward the central portion in the axial direction of the spool of the first portion 74a and along the axial direction of the spool. The axial groove 72 communicates with the first space portion 69. Further, the axial groove 72 is formed above (vertically above) the spool 45. As shown in FIG. 7, the axial groove 72 has a substantially arc-shaped cross section. Note that the cross-sectional shape of the axial groove 72 is not limited to this, and for example, it may be a V-shaped groove. The flow path resistance of the axial groove 72 is smaller than the flow path resistance of the spiral groove 67.

[0048] As shown in FIGS. 5 and 6, the circumferential groove 73 is formed adjacent to the axial groove 72 on the inner side in the axial direction of the spool (the center in the axial direction of the spool 45). In the present embodiment, the circumferential groove 73 is formed near the central portion in the axial direction of the first portion 74a. In other words, the circumferential groove 73 is formed adjacent to the axial groove 72 on the side opposite to the end of the axial groove 72 on the side communicating with the pilot chamber 57. The axial groove 72 and the circumferential groove 73 communicate with each other. The groove depth of the circumferential groove 73 is formed larger than the groove depth of the axial groove 72.

[0049] As shown in FIGS. 5 and 6, the control valve V of the present embodiment has an air bleeding circuit 76 for discharging the air accumulated in the pilot chamber 57. The air bleeding circuit 76 is a circuit that discharges the air accumulated in the pilot chamber 57 by communicating the pilot chamber 57 with the discharge passage 51 and leaking a part of the pilot oil introduced into the pilot chamber 57 to the discharge passage 51 when the spool 45 moves a predetermined amount from the neutral position 23 by the pilot oil introduced into the pilot chamber 57. By discharging the air accumulated in the pilot chamber 57 by the air bleeding circuit 76, the switching responsiveness of the spool 45 (control valve V) can be improved.

[0050] As shown in FIG. 4, the air bleeding circuit 76 is provided on both sides in the spool axial direction of the control valve V. The air bleeding circuit 76 on one end side 48A in the spool axial direction of the control valve V is a flow path for discharging air by leaking the pilot oil introduced from the first pilot pipeline 43A to the first pilot chamber 57A. The air bleeding circuit 76 on the other end side 48B in the spool axial direction of the control valve V is a flow path for discharging air by leaking the pilot oil introduced from the second pilot pipeline 43B to the second pilot chamber 57B.

[0051] In FIGS. 3 and 8, part A schematically shows the state of the air bleeding circuit 76. The first state 78 in part A shows the state of the air bleeding circuit 76 when the control valve V (spool 45) is in the neutral position 23. The second state 79 in part A shows the state of the air bleeding circuit 76 when the control valve V (spool 45) is switched to the first switching position 24. The third state 80 in part A shows the state of the air bleeding circuit 76 when the control valve V (spool 45) is switched to the second switching position 25.

[0052] As shown in FIG. 3, when the control valve V is in the neutral state (neutral position 23), as shown in the first state 78, the leakage of the pilot oil from the pilot chamber 57 to the discharge passage 51 by the air bleeding circuit 76 is blocked. As shown in FIG. 8, when the control valve V is switched to the first switching position 24, as shown in the second state 79, the air bleeding circuit 76 on one end side of the control valve V leaks the pilot oil supplied to the first pressure receiving portion 42A via the throttle 81 to the hydraulic oil tank T1. On the other hand, the control valve V the leakage of the pilot oil by the air bleeding circuit 76 on the other end side is blocked.

[0053] When the control valve V is switched to the second switching position 25 (not shown), as shown in the third state 80, the leakage of the pilot oil by the air bleeding circuit 76 on one end side of the control valve V is blocked, and the air bleeding circuit 76 on the other end side of the control valve V leaks the pilot oil to the hydraulic oil tank T1 via the throttle 81. Next, the operating operation of the air bleeding circuit 76 will be described in detail with reference to the cross-sectional view of the control valve V.

[0054] As shown in FIGS. 5 and 6, the air bleeding circuit 76 includes a spiral groove 67, an annular groove 68, an axial groove 72, and a circumferential groove 73. As shown in FIGS. 5 and 6, when the control valve V is in the neutral position 23, the spiral groove 67 and the annular groove 68 are located on the outer side in the spool axial direction of the axial groove 72 and are not in communication with the discharge passage 51. Further, since the outer periphery of the land portion 71 is in contact with the inner surface of the support hole portion 74 (spool hole 47) over the entire circumference between the circumferential groove 73 and the discharge passage 51, the axial groove 72 and the circumferential groove 73 are also not in communication with the discharge passage 51. That is, when the control valve V is in the neutral position 23, the communication between the pilot chamber 57 and the discharge passage 51 by the air bleeding circuit 76 is blocked.

[0055] Furthermore, when the control valve V is in the neutral position 23, the outer surface of the groove forming portion 65 on the outer side in the spool axis direction abuts against the spring guide 62a of the first spring seat 62, and the flow of pilot oil from the flow path 64 formed by the gap between the inner peripheral surface of the spring guide 62a of the first spring seat 62 and the outer peripheral surface of the guide portion 58 to the second space portion 70 is blocked. Note that the flow of pilot oil from the flow path 64 to the second space portion 70 does not necessarily have to be strictly blocked. For example, there may be a play (minute gap) between the spool 45 and the spring seat 62, and when the control valve V is in the neutral position 23, the flow path 64 and the second space portion 70 may communicate with each other through the gap caused by the play.

[0056] Also, as shown in FIG. 6, a slit that communicates the pilot chamber 57 and the second space portion 70 may be formed in the contact portion 82 of the spring seat 62 with the valve body 46, and the pilot chamber 57 and the second space portion 70 may be constantly communicated with each other through the slit. By forming the above slit, as will be described later, when the spool 45 moves from the neutral position 23 and pilot oil flows from the pilot chamber 57 to the second space portion 70 through the flow path 64, a constant flow rate can be ensured. For example, only the flow of oil from the flow path 64 to the second space portion 70 may be too restricted, and by forming the above slit, a constant flow rate can be ensured. That is, when it is desired to ensure a constant flow rate, the slit may be provided as described above.

[0057] FIGS. 9 to 12 show a state in which the control valve V is switched from the neutral position 23 to the first switching position 24. As shown in FIGS. 9 and 10, when the control valve V is switched to the first switching position 24, the spool 45 moves leftward from the neutral position 23. When the spool 45 moves from the neutral position 23 to the first switching position 24, the inner portion of the spiral groove 67 in the spool axis direction and the annular groove 68 move from the outer side (pilot chamber 57 side) of the axial groove 72 in the spool axis direction to a position communicating with the discharge passage 51 through (across) the axial groove 72 and the circumferential groove 73. And at the first switching position 24, as shown in FIG. 10, the inner portion of the spiral groove 67 in the spool axis direction communicates across the circumferential groove 73 and the discharge passage 51.

[0058] As shown in FIGS. 10 and 11, when the control valve V is switched to the first switching position 24, at one end side 48A in the axial center direction of the spool 45, the groove forming portion 65 separates from the spring guide 62a and the flow passage 64 communicates with the second space portion 70. Also, the annular groove 68 and the inner end portion 67a of the spiral groove 67 in the spool axis direction communicate with the discharge passage 51, and the outer portion of the spiral groove 67 in the spool axis direction overlaps with the circumferential groove 73 and the axial groove 72, so that the circumferential groove 73 and the axial groove 72 communicate with the spiral groove 67. That is, the first pilot chamber 57A communicates with the discharge passage 51 via the air bleeding circuit 76. Therefore, a part of the pilot oil introduced into the first pilot chamber 57A flows through the flow passage 64 → the second space portion 70 → the first space portion 69 → the axial groove 72 and the circumferential groove 73 → the spiral groove 67 → the annular groove 68 to the discharge passage 51 and then flows from the discharge passage 51 toward the hydraulic oil tank T1. Also, the pilot oil introduced into the first space portion 69 flows into the spiral groove 67 from the outer end portion 67b of the spiral groove 67 in the spool axis direction, flows through the spiral groove 67 and the annular groove 68 to the discharge passage 51, and then flows from the discharge passage 51 to the hydraulic oil tank T1.

[0059] On the one hand, as shown in FIG. 9, when the spool 45 moves leftward from the neutral position 23, at the other end side 48B in the axial direction of the control valve V, the groove forming portion 65 pushes the first spring seat 62 to compress the neutral spring 26B, and the guide portion 58 abuts against the second spring seat 63 to stop the movement of the spool 45. Further, as shown in FIG. 12, since the circumferential groove 73 does not communicate with the discharge passage 51, the leakage of the pilot oil through the air bleeding circuit 76 is blocked.

[0060] Also, when switching the control valve V from the neutral position 23 to the second switching position 25, the spool 45 moves rightward from the neutral position 23. At the other end side 48B in the axial direction of the control valve V, the second pilot chamber 57B and the discharge passage 51 communicate with each other through the air bleeding circuit 76, and a part of the pilot oil introduced into the second pilot chamber 57B leaks into the discharge passage 51 through the air bleeding circuit 76. Also, at the one end side 48A in the axial direction of the control valve V, the leakage of the pilot oil through the air bleeding circuit 76 is blocked. The operation when switching the control valve V to the second switching position 25 is the same as the operation when switching the control valve V to the first switching position 24, so the description is omitted.

[0061] By the way, for example, if a part of the pilot oil introduced into the pilot chamber 57 is allowed to leak only through the spiral groove 67 without providing the circumferential groove 73 and the axial groove 72, air tends to remain in the pilot chamber 57. Specifically, referring to FIG. 10 for explanation, the air in the pilot chamber 57 tends to remain in the portion above the height position H1 of the end portion 67b (the inlet side end portion of the pilot oil) on the outer side in the spool axial direction (the pilot chamber 57 side) of the spiral groove 67. Further, since the spool 45 is rotatable about its axis, for example, when assembling the spool 45, there is a variation in the height of the inlet side end portion 67b of the spiral groove 67 depending on the rotational position of the spool 45 about its axis. When the height of the inlet side end portion 67b of the spiral groove 67 becomes lower than the position shown in FIG. 10, it becomes even more difficult for the air to escape. Thus, with only the spiral groove 67, there is a variation in the amount of air remaining (the amount of air bleeding) in the pilot chamber 57, and the switching responsiveness of the spool 45 is not stable. Also, if the spiral groove 67 is not provided and the first space portion 69 and the discharge passage 51 are communicated only through the axial groove 72 to cause the pilot oil in the pilot chamber 57 to leak, the leakage amount of the pilot oil tends to become excessive.

[0062] In contrast, in the present embodiment, by using the axial groove 72 and the spiral groove 67 in combination, it is possible to stably vent the air in the pilot chamber 57 while suppressing the leakage amount of the pilot oil. Specifically, in the present embodiment, the leakage amount of the pilot oil is determined by the flow path resistance of the axial groove 72 and the spiral groove 67 from the first space portion 69 to the circumferential groove 73 and the flow path resistance of the spiral groove 67 from the circumferential groove 73 to the discharge path 51. That is, by connecting the circumferential groove 73 and the discharge path 51 with the spiral groove 67, the flow path resistance is made larger than when the circumferential groove 73 and the discharge path 51 are connected with the axial groove 72 (when the pilot chamber 57 and the discharge path 51 are connected with the axial groove 72), and the leakage amount of the pilot oil can be suppressed. Also, although air tends to accumulate in the upper part of the pilot chamber 57, since the pilot oil in the pilot chamber 57 leaks from the axial groove 72 located above the spool 45, that is, since the pilot oil leaks from a high position in the pilot chamber 57, the air in the pilot oil introduced into the pilot chamber 57 can be vented well, and the remaining amount of air in the pilot chamber 57 can be reduced. Further, since the position of the axial groove 72 does not change, the air can be stably vented regardless of the rotational position of the spool 45 around its axis. Therefore, since the leakage amount of the pilot oil is limited by the spiral groove 67, the leakage amount of the pilot oil can also be suppressed, and the air in the pilot chamber 57 can be stably vented.

[0063] As described above, in order to vent the air in the pilot chamber 57, by using the axial groove 72 and the spiral groove 67 in combination, it is possible to stably vent the air in the pilot chamber 57 while suppressing the leakage amount of the pilot oil. In addition, as the throttle 81 of the air bleeding circuit 76, the portion from the circumferential groove 73 in the spiral groove 67 to the discharge passage 51 corresponds thereto. Specifically, the range H2 (see FIGS. 10 and 11) between the end on the discharge passage 51 side of the circumferential groove 73 and the end on the circumferential groove 73 side of the discharge passage 51 in the spiral groove 67 corresponds to the portion of the throttle 81. If the circumferential groove 73 is not provided, the length of the spiral groove 67 corresponding to the throttle 81 changes depending on the rotational position around the axis of the spool 45, and the corresponding portion of the throttle 81 becomes unstable. Therefore, the presence of the circumferential groove 73 can stabilize the corresponding portion of the throttle 81. When machining the axial groove 72, the circumferential groove 73 is machined first, and then the machining of the axial groove 72 is performed with a tool. Therefore, the circumferential groove 73 is also necessary for machining the axial groove 72.

[0064] In the above-described embodiment, an example in which a single axial groove 72 is formed in the spool hole 47 at one end side 48A and the other end side 48B in the spool axis direction of the spool hole 47 has been shown. However, the present invention is not limited to this, and a plurality of axial grooves 72 may be formed around the spool 45 (the axial grooves 72 may be formed at intervals in the circumferential direction of the spool hole 47). Thereby, when mounting the control valve V (control valve CV) on the work machine 1 (airframe 2), depending on the mounting situation, a plurality of orientations of the control valve V (control valve CV) can be selected, and the versatility of the installation of the control valve V (control valve CV) can be enhanced. Specifically, for example, by also forming the axial groove 72 below the spool 45 in FIG. 4 (for example, at a position where the angle between the axial grooves 72 with respect to the axis of the spool 45 is 180 degrees), when the control valve V is installed with the lower surface of the control valve V in FIG. 4 facing upward, the control valve V can be installed such that the axial groove 72 is located above the spool 45. Further, by also forming the axial groove 72 on the front side of the spool 45 in FIG. 4 (for example, at a position where the angle between the axial grooves 72 with respect to the axis of the spool 45 is 90 degrees), when the control valve V is installed with the front side surface of the control valve V in FIG. 4 facing upward, the control valve V can be installed such that the axial groove 72 is located above the spool 45. Further, by also forming the axial groove 72 on the back side of the spool 45 in FIG. 4 (for example, at a position where the angle between the axial grooves 72 with respect to the axis of the spool 45 is 90 degrees), when the control valve V is installed with the back side surface of the control valve V in FIG. 4 facing upward, the control valve V can be installed such that the axial groove 72 is located above the spool 45. Note that the positions of the axial grooves 72 in the case of providing a plurality of axial grooves 72 around the spool described above are merely examples and are not limiting.

[0065] Also, in the above-described embodiment, the air bleeding circuit 76 is provided on both the one end side 48A and the other end side 48B in the spool axis direction. However, the present invention is not limited to this, and the air bleeding circuit 76 may be provided on only either one of the one end side 48A and the other end side 48B in the spool axis direction. In addition, in this embodiment, a pilot-operated switching valve is exemplified as the control valve V, but the present invention is not limited thereto, and the control valve V may employ a pilot-type proportional solenoid valve. The pilot-type proportional solenoid valve is a valve that controls the direction and flow rate of the hydraulic oil by moving the spool 45 with a pilot control pressure controlled by a proportional solenoid. Specifically, the pilot-type proportional solenoid valve is a two-stage direction / flow rate control valve that employs a proportional solenoid pressure reducing valve having two proportional solenoids in the pilot section. The flow rate is controlled by changing the input current to the proportional solenoid, and the direction is controlled by applying current to one of the two proportional solenoids.

[0066] Alternatively, a pair of proportional solenoid valves formed separately from the control valve V may be provided such that a pilot control pressure is supplied from one proportional solenoid valve to the first pressure receiving portion 42A and a pilot control pressure is supplied from the other proportional solenoid valve to the second pressure receiving portion 42B, so that the direction and flow rate of the hydraulic oil flowing to the hydraulic actuator AC (MT, ML, MR, C1 to C5) of the control valve V are controlled.

[0067] In addition, in this embodiment, the spiral groove 67 is provided from the position communicating with the discharge passage 51 to the position communicating with the pilot chamber 57, but the present invention is not limited thereto, and the spiral groove 67 may be provided at least up to the position communicating with the circumferential groove 73 from the discharge passage 51. In addition, in this embodiment, when the spool 45 is in the neutral position 23, the pilot chamber 57 and the discharge passage 51 are described as being blocked, but the present invention is not limited thereto, and when the spool 45 is in the neutral position 23, the pilot chamber 57 and the discharge passage 51 may be configured to communicate with each other via the axial groove 72 and the spiral groove 67.

[0068] The control valve V of the present embodiment includes a valve body 46, a spool hole 47 formed in the valve body 46, a spool 45 slidably incorporated in the spool hole 47, a pilot chamber 57 into which pilot oil for operating the spool 45 is introduced, a discharge passage 51 for discharging the hydraulic oil to the outside of the valve body 46, a spiral groove 67 formed spirally on the outer periphery of the spool 45 and communicating with the discharge passage 51, and at least one axial groove 72 formed on the inner surface of the spool hole 47 along the axial direction of the spool 45 and communicating the pilot chamber 57 and the spiral groove 67.

[0069] According to this configuration, the spiral groove 67 communicates with the discharge passage 51, and the pilot chamber 57 communicates with the spiral groove 67 via the axial groove 72. The pilot oil in the pilot chamber 57 leaks from the spiral groove 67 to the discharge passage 51 through the axial groove 72, and air escapes. That is, since the pilot oil leaks from the spiral groove 67 via the axial groove 72 formed in the valve body 46, air can be stably discharged regardless of the rotational position of the spool 45 around its axis. In addition, in a state where the valve body 46 is installed such that the spool 45 extends in the horizontal direction, the pilot chamber 57 is adjacent to the spool hole 47 in the axial direction of the spool 45, and the axial groove 72 is configured to be located above the spool 45.

[0070] According to this configuration, air can be discharged from a high position of the pilot chamber 57, so that the remaining air in the pilot chamber 57 can be reduced. In addition, a plurality of axial grooves 72 are formed around the spool 45. According to this configuration, a plurality of orientations of the control valve V can be selected according to the installation situation, and the versatility of the installation of the control valve V can be improved. In addition, the flow resistance of the spiral groove 67 is greater than the flow resistance of the axial groove 72. According to this configuration, the pilot oil flowing from the pilot chamber 57 to the axial groove 72 is restricted by the spiral groove 67 and flows into the discharge passage 51. Therefore, while suppressing the leakage amount of the pilot oil, the air in the pilot chamber 57 can be stably vented.

[0071] In addition, there is a circumferential groove 73 formed circumferentially on the inner surface of the spool hole 47. The circumferential groove 73 communicates with the axial groove 72 on the side opposite to the end of the axial groove 72 that communicates with the pilot chamber 57. The discharge passage 51 is located at a distance from the circumferential groove 73 on the side opposite to the axial groove 72. The spiral groove 67 moves from the axial groove 72 side toward the discharge passage 51 to communicate the circumferential groove 73 and the discharge passage 51.

[0072] According to this configuration, the pilot oil introduced into the pilot chamber 57 flows from the axial groove 72 to the circumferential groove 73, and then flows from the circumferential groove 73 to the discharge passage 51 via the spiral groove 67. A throttle 81 that restricts the amount of pilot oil leaking into the discharge passage 51 is formed by the portion between the circumferential groove 73 and the discharge passage 51 in the spiral groove 67. Therefore, if the circumferential groove 73 is not provided, the length of the spiral groove 67 corresponding to the throttle 81 changes depending on the rotational position of the spool 45 around its axis, and the corresponding portion of the throttle 81 becomes unstable. However, the presence of the circumferential groove 73 can stabilize the corresponding portion of the throttle 81.

[0073] In addition, when the spool 45 is in the neutral position 23, the pilot chamber 57 and the discharge passage 51 are blocked. When the spool 45 is moved by a predetermined amount from the neutral position 23 by the pilot oil introduced into the pilot chamber 57, the pilot chamber 57 and the discharge passage 51 may be communicated via the axial groove 72 and the spiral groove 67. According to this configuration, the leakage amount of the pilot oil when the spool 45 is in the neutral position 23 can be suppressed.

[0074] In addition, the working machine 1 according to the present embodiment includes the control valve V described above. Therefore, the air in the pilot chamber can be appropriately vented regardless of the mounting status of the control valve V and the posture of the working machine 1. As described above, one embodiment of the present invention has been explained. However, it should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and it is intended that all modifications within the meaning and scope equivalent to the claims be included.

Explanation of Reference Numerals

[0075] 23 Neutral position 45 Spool 46 Valve body 47 Spool hole 51 Discharge path 57 Pilot chamber 67 Spiral groove 72 Axial groove 73 Circumferential groove V control valve

Claims

1. a valve body, a spool hole formed in the valve body, a spool slidably incorporated in the spool hole, a pilot chamber into which pilot oil for operating the spool is introduced, a discharge passage for discharging hydraulic oil to the outside of the valve body, a spiral groove formed spirally on the outer periphery of the spool, at least one axial groove formed along the axial direction of the spool on the inner surface of the spool hole and communicating the pilot chamber and the spiral groove, a circumferential groove formed circumferentially on the inner surface of the spool hole, the circumferential groove communicating with the axial groove on the side opposite to the end of the axial groove communicating with the pilot chamber, comprising, the discharge passage is spaced apart from the circumferential groove on the side opposite to the axial groove, and in a state where the valve body is installed such that the spool extends in the horizontal direction, the pilot chamber is adjacent to the spool hole in the axial direction of the spool, and the axial groove is located above the spool, the spiral groove, when the spool is in the neutral position, is located closer to the pilot chamber side than the axial groove, and when the spool is moved by a predetermined amount from the neutral position by the pilot oil introduced into the pilot chamber, communicates the pilot chamber and the discharge passage without passing through the axial groove and the circumferential groove and is configured to communicate directly with the axial groove and the circumferential groove. A control valve.

2. A valve body, a spool hole formed in the valve body, a spool slidably incorporated in the spool hole, a pilot chamber into which pilot oil for operating the spool is introduced, a discharge passage for discharging hydraulic oil to the outside of the valve body, a spiral groove formed spirally on the outer periphery of the spool, at least one axial groove formed along the axial direction of the spool on the inner surface of the spool hole and communicating the pilot chamber and the spiral groove, a circumferential groove formed circumferentially on the inner surface of the spool hole, the circumferential groove communicating with the axial groove on the side opposite to the end of the axial groove communicating with the pilot chamber, a first spring seat disposed on the spool side inside the pilot chamber, a second spring seat disposed on the pilot oil supply side inside the pilot chamber, A neutral spring interposed between the first spring sheet and the second spring sheet and biasing the spool to a neutral position via the first spring sheet, comprising, the discharge passage is located at a distance from the axial groove on the side opposite to the circumferential groove, and in a state where the valve body is installed such that the spool extends in the horizontal direction, the pilot chamber is adjacent to the spool hole in the axial direction of the spool, and the axial groove is configured to be located above the spool, the spiral groove is, when the spool is in the neutral position, it is located on the pilot chamber side of the axial groove, and when the spool moves a predetermined amount from the neutral position by the pilot oil introduced into the pilot chamber, it is configured to communicate the pilot chamber with the discharge passage and to communicate the axial groove with the circumferential groove, the spool has a guide portion located on the pilot chamber side of the spiral groove, the first spring sheet has a spring guide that is externally fitted to the guide portion so as to be relatively movable in the axial direction of the spool, a contact portion that contacts the valve body, and a slit formed in the contact portion, the slit communicates the pilot chamber with the space portion on the outer peripheral side of the spiral groove, a control valve configured such that when the spool moves the predetermined amount from the neutral position by the pilot oil introduced into the pilot chamber, the pilot oil from the pilot chamber flows through a gap provided between the inner peripheral surface of the spring guide and the outer peripheral surface of the guide portion and the slit, and then through the spiral groove, the axial groove, and the circumferential groove to the discharge passage.

3. The control valve according to claim 1 or 2, wherein a plurality of axial grooves are formed around the spool.

4. The control valve according to any one of claims 1 to 3, wherein the flow path resistance of the spiral groove is greater than the flow path resistance of the axial groove.

5. A working machine provided with the control valve according to any one of claims 1 to 4.

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