JP2020034023A - Direction switch valve device - Google Patents

Abstract

To provide a direction switch valve device which can connect a discharge passage opened/closed by a relief valve to a tank without complicating that, and can improve the freedom of alignment when used with other direction switch valve devices.SOLUTION: A direction switch valve device 1 includes: a valve body block 10; a spool 20; a lock valve 30 which opens/closes an actuator passage 14 of the valve body block 10; and a relief valve 40 which opens/closes according to the internal pressure of the actuator passage 14. A discharge passage 100 connecting the actuator passage 14 and a tank passage 15 is provided on the valve body block 10. The relief valve 40 opens/closes the discharge passage 100 according to the internal pressure of the actuator passage 14.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a spool type directional switching valve device including a lock valve and a relief valve.

  A construction machine usually controls operating parts such as an arm and a boom by a directional control valve device.The directional control valve device used in such a construction machine generally includes a valve body having a spool hole, and a sliding member that slides into the spool hole. A freely provided spool, and the supply and cutoff of hydraulic oil are switched by moving the spool in the valve body.

  When the operation of the arm or boom of the construction machine is controlled by the above-described directional switching valve device, a hydraulic cylinder is provided between the directional switching valve device and the arm or the boom, and according to hydraulic oil from the directional switching valve device. An arm and a boom are driven by a hydraulic cylinder that expands and contracts. Here, when a situation occurs in which the arm or the boom is kept stationary, the directional switching valve device disconnects the connection with the pump that is the supply source of the hydraulic oil and discharges the hydraulic oil from the hydraulic cylinder. Is switched to a state of disconnecting the connection with the tank.

  However, in a heavy-duty directional switching valve device for an arm or a boom, the hydraulic oil passes between the spool and the inner peripheral surface of the spool hole due to the weight of the arm or the boom only by shutting off the pump and the tank. Leaks into the tank, and as a result, it may be difficult to keep the arm or boom stationary. Therefore, a lock valve for preventing leakage of hydraulic oil is usually provided in a direction switching valve device for an arm or a boom.

  In the direction switching valve device for the arm or the boom, a relief valve is usually provided in addition to the lock valve. The relief valve is a valve that discharges the hydraulic oil when the hydraulic oil in the hydraulic cylinder becomes abnormally high in pressure, for example, and reduces the pressure of the hydraulic oil by such discharge.

  Various techniques related to the directional switching valve device including the lock valve and the relief valve as described above have been conventionally proposed. For example, Patent Document 1 discloses that a lock valve and a relief valve are arranged side by side in one directional switching valve device. The structure provided is disclosed.

Japanese Utility Model Publication No. 7-47604

  In general, in a construction machine, a plurality of directional control valve devices corresponding to a plurality of operating portions are unitized in a state of being stacked, and the unit is incorporated therein. Patent Literature 1 does not disclose a detailed structure of a passage for discharging hydraulic oil when a relief valve provided in a directional switching valve device is opened, but this directional switching valve device is different from other directional switching valve devices. On the premise that they are arranged so as to overlap with each other, the above-described passage for discharging the hydraulic oil is connected to a passage and a tank passage formed in another adjacent directional switching valve device, and the tank is connected through these passages to the tank. It is considered to have a structure to be connected.

  However, in the above structure, a sealing mechanism is required at a passage connecting portion between the adjacent directional control valve devices, so that the structure is complicated. Also, a direction switching valve device provided with a relief valve and another direction switching valve device formed with a passage connected to the hydraulic oil discharge passage formed in the direction switching valve are always adjacent to each other. Since they must be arranged and fastened to each other, the degree of freedom of arrangement of the plurality of directional control valve devices is limited.

  Specifically, it is preferable that the other directional switching valve device can easily secure a space for forming a passage connected to the passage for discharging the hydraulic oil. For example, a swivel unit that does not require a relief valve is preferable. Directional switching valve device. In this case, in a unit composed of a plurality of directional control valve devices, the directional control valve device for the arm or the boom and the directional control valve device for the turning portion must be adjacent to each other. The degree of freedom of arrangement of the valve device is restricted.

  The present invention has been made in view of the above circumstances, and can be connected to a tank without complicating a discharge passage for opening and closing a relief valve, and an arrangement when used together with another direction switching valve device. It is an object of the present invention to provide a direction switching valve device capable of improving a degree of freedom.

  A directional switching valve device according to the present invention includes a spool hole, an actuator passage opening to the spool hole and connected to an actuator, a tank passage opening to the spool hole and connected to a tank, and the actuator passage and the tank. A valve body block having a discharge passage connecting the passage, a spool, and a lock valve for opening and closing the actuator passage at a predetermined opening and closing position set in the actuator passage, the lock valve being directed from the spool hole toward the actuator. A lock valve that opens and closes in response to the internal pressure of a passage portion located upstream with respect to the open / close position in the direction, and in a closed state, maintains a blocked state of flow in a direction from the actuator toward the spool hole; Opening according to the internal pressure of the actuator passage. Comprises a relief valve which, a directional control valve apparatus. It is.

  The lock valve is provided between the spool and the relief valve in a radial direction of the spool, and a part of the discharge passage is formed by an annular passage portion formed on an outer periphery of the lock valve. The outer peripheral surface of the lock valve may define the annular passage portion.

  The relief valve may open and close according to a pressure inside a passage located downstream of the lock valve in a direction from the spool hole in the actuator passage toward the actuator.

  The valve body block further includes a supply passage that opens to the spool hole and is connected to a pump.The spool connects the supply passage and the actuator passage according to a position of the supply passage. To shut off the tank passage, or to shut off the supply passage and the actuator passage and to shut off the actuator passage and the tank passage, or to connect the actuator passage and the tank passage and The supply passage and the actuator passage may be shut off.

  Further, the direction switching valve device according to the present invention includes a spool hole, an actuator passage opening to the spool hole and connected to an actuator, a tank passage opening to the spool hole and connected to a tank, and the actuator passage. A valve body block including a discharge passage connecting the tank passage, a spool, a lock valve that opens and closes the actuator passage at a predetermined opening and closing position set in the actuator passage, and a relief valve. The lock valve closes the actuator passage in accordance with an internal pressure of a passage portion located on an upstream side with respect to the opening / closing position in a direction from the spool hole toward the actuator, and closes the actuator passage in a direction from the actuator toward the spool hole. Shut off the flow, the relief valve is connected to the actuator To open the discharge passage in response to the internal pressure of the road, a directional control valve apparatus.

  ADVANTAGE OF THE INVENTION According to the directional control valve apparatus which concerns on this invention, while the discharge passage which a relief valve opens and closes can be connected to a tank, without complicating, the degree of freedom of arrangement | positioning when used with another directional control valve apparatus is improved. Can be improved.

It is a sectional view of a direction change valve device concerning one embodiment of the present invention. FIG. 2 is an enlarged sectional view of a lock valve provided in the direction switching valve device shown in FIG. 1. FIG. 3 is a cross-sectional view along the line III-III in FIG. 1.

  Hereinafter, a directional control valve device 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a direction switching valve device 1 according to the present embodiment. FIG. 1 shows only a part of the cross section of the directional control valve device 1 for convenience of explanation. The direction switching valve device 1 is a valve that controls the flow of hydraulic oil supplied from the pump P to the actuator A and the hydraulic oil discharged from the actuator A to the tank T.

  In the present embodiment, the direction switching valve device 1 is configured to supply hydraulic oil from the pump P to an actuator A (specifically, a hydraulic cylinder) for operating an arm or a boom of a construction machine. . However, such a configuration is an example, and the actuator A connected to the direction switching valve device 1 and the object driven by the actuator A are not particularly limited.

  The direction switching valve device 1 includes a valve body block 10 having a spool hole 11 formed therein, a spool 20 slidably provided in the spool hole 11, a lock valve 30, a relief valve 40, and a pilot chamber forming cover 50. Have.

  The valve body block 10 is, for example, a flat rectangular parallelepiped block body, and the spool hole 11 is formed inside the valve body block 10. The spool hole 11 is a hole having a circular cross section, and is open from the plane portion of the valve body block 10 to the outside along the axial direction. The spool 20 has a cylindrical shape, is provided in the spool hole 11 coaxially with the spool hole 11, and is slidable in the spool hole 11 along the axial direction.

  The drive system for sliding the spool 20 in the axial direction is not particularly limited. For example, a mechanical drive system, a hydraulic pilot drive system, or an electromagnetic drive drive system can be adopted. In this embodiment, the hydraulic pilot drive system is used. Has been adopted.

  In the following description, the direction in which the spool hole 11 opens in FIG. 1 may be referred to as one side in the axial direction of the spool hole 11 or the spool 20, and the opposite side may be referred to as the other side in the axial direction. Also, a direction parallel to the axial direction of the spool hole 11 or the spool 20 may be referred to as an axial direction.

  The spool 20 has a plurality of lands 20L arranged apart from each other in the axial direction, and a plurality of notches 20N provided between the lands 20L. In FIG. 1, the outer diameter of each land portion 20 </ b> L substantially matches the inner diameter of the spool hole 11. On the other hand, the outer diameter of each notch 20N is smaller than the inner diameter of the spool hole 11.

  When the land portion 20L is arranged so as to straddle each opening of two passages described later that open to the spool hole 11, and to cover the whole of each opening, the flow of the hydraulic oil between these two passages is shut off. . On the other hand, when the notch portion 20N is disposed so as to straddle each of the above-described opening portions, the notch portion 20N forms a passage connecting these two passages, and allows the flow of the hydraulic oil. In addition, the spool 20 can not only switch connection and disconnection (that is, whether or not there is connection) between the passages, but also adjust the flow path opening (that is, the valve opening) between the passages according to the position.

  The valve body block 10 includes, in addition to the spool hole 11, an upstream supply passage 12, a downstream supply passage 13, an actuator passage 14, a tank passage 15, and a discharge passage 100 connecting the actuator passage 14 and the tank passage 15. Prepare. Hydraulic oil flows through these passages.

  The upstream supply passage 12 and the downstream supply passage 13 are passages for supplying hydraulic oil from the pump P to the actuator A. The upstream supply passage 12 is connected to the pump P, and allows the hydraulic oil supplied from the pump P to flow into the downstream supply passage 13 via the check valve 61. Specifically, when the hydraulic oil from the pump P opens the check valve 61, the upstream supply passage 12 and the downstream supply passage 13 are connected, and the hydraulic oil is supplied from the upstream supply passage 12 to the downstream supply passage 13. Inflow.

  The upstream supply passage 12 is a hole that extends without directly intersecting with the spool hole 11 at a position radially outward with respect to the spool hole 11, and has a check at a radially outer end forming an outlet thereof. A valve seat for the valve 61 is formed, and the valve 61 is connected to the downstream supply passage 13 via the valve seat. The downstream supply passage 13 extends so as to approach the spool hole 11 as it advances from the connection position with the upstream supply passage 12 to one side in the axial direction of the spool hole 11.

  The downstream supply passage 13 is a passage for supplying the hydraulic oil flowing into the upstream supply passage 12 to the actuator A via the check valve 61, the spool hole 11, and the actuator passage 14, and opens to the spool hole 11. When the downstream supply passage 13 is closed at the opening to the spool hole 11 by the land portion 20L of the spool 20 (the state shown in FIG. 1), the space between the spool hole 11 and the actuator passage 14 and the downstream supply passage 13 is provided. The connection is interrupted or the valve opening is limited. The supply passage referred to in the present invention is a portion corresponding to the upstream supply passage 12 and the downstream supply passage 13 in the present embodiment.

  The actuator passage 14 is a passage that opens to the spool hole 11 and is connected to the actuator A. The actuator passage 14 is adjacent to the downstream supply passage 13 at one position in the axial direction of the spool hole 11 with respect to the downstream supply passage 13. ing. The opening of the actuator passage 14 to the spool hole 11 is located on one axial side of the spool hole 11 with respect to the opening of the downstream supply passage 13 to the spool hole 11. The actuator passage 14 opens in the spool hole 11 along the radial direction of the spool 20 and opens outside the valve body block 10 along the radial direction of the spool 20.

  The actuator passage 14 in the present embodiment includes a first portion 14A extending radially from an opening portion to the spool hole 11, and a spool hole 11 extending from an end of the first portion 14A opposite to the spool hole 11 side. A second portion 14B extending on one side in the axial direction of the second portion 14B, and a third portion extending radially from an end portion of the second portion 14B opposite to the first portion 14A side and opening from the valve body block 10. 14C. Although details will be described later, a lock valve seat 14S of the lock valve 30 is formed in the second portion 14B.

  The tank passage 15 is a passage that opens to the spool hole 11 and is connected to the tank T, and is a passage for returning the hydraulic oil discharged from the actuator A to the tank T. The tank passage 15 is connected to or disconnected from the actuator passage 14 depending on the position of the spool 20.

  The tank passage 15 in the present embodiment has the opening to the spool hole 11 positioned on one side in the axial direction with respect to the opening to the spool hole 11 of the actuator passage 14, and It extends from the opening to the other axial side of the spool hole 11. Accordingly, when the tank passage 15 is connected to the actuator passage 14, the hydraulic oil from the actuator passage 14 flows to the other side in the axial direction of the spool hole 11 via the opening of the tank passage 15 to the spool hole 11. Will flow and then be discharged.

  The direction switching valve device 1 has the above-described configuration, so that the first state in which the supply passages 12 and 13 are connected to the actuator passage 14 according to the position of the spool 20 in the spool hole 11 and the supply passages 12 and 13. And a third state in which the actuator path 14 and the tank path 15 are connected to each other. More specifically, in the first state, the supply passages 12, 13 and the actuator passage 14 are connected, and the actuator passage 14 and the tank passage 15 are shut off. In the second state, the supply passages 12, 13 and the actuator passage 14 are shut off, and the actuator passage 14 and the tank passage 15 are shut off. In the third state, the actuator passage 14 and the tank passage 15 are connected, and the supply passages 12, 13 and the actuator passage 14 are shut off.

  Here, in the present embodiment, as described above, a hydraulic pilot type driving structure is employed as the driving method of the spool 20, but the structure is such that the opening of one side of the spool hole 11 in the valve body block 10 in the axial direction is provided. And a pilot chamber forming cover 50 provided at one end of the spool hole 11 in the axial direction with respect to the end of the spool 20 facing the outside and the valve body block 10.

  The pilot chamber forming cover 50 has a pilot chamber 51 for a spool. The pilot chamber 51 for the spool is connected to an opening on one side of the spool hole 11 in the valve body block 10 in the axial direction. Fixed. The pilot chamber forming cover 50 has a first input port 52 that opens to the spool pilot chamber 51 on the side opposite to the spool hole 11 side. Thereby, the pilot pressure can be applied to the end of the spool 20 facing the outside from the opening on one side in the axial direction of the spool hole 11 by the hydraulic oil flowing into the first input port 52. On the other hand, although not shown, the end opposite to the end of the spool 20 on which the pilot pressure acts is urged toward the spool pilot chamber 51 by a spring. Thus, in the hydraulic pilot type drive structure in the present embodiment, the position of the spool 20 can be adjusted by appropriately adjusting the pilot pressure from the spool pilot chamber 51.

  Next, the lock valve 30 will be described. The lock valve 30 is provided outside the spool 20 or the spool hole 11 in the radial direction of the spool 20 (or the spool hole 11), and is particularly provided at a position overlapping the spool 20 or the spool hole 11 in the radial direction. The lock valve 30 in the present embodiment is a valve that opens and closes the actuator passage 14 with the above-described lock valve seat 14S (corresponding to a predetermined opening / closing position in the present invention) set in the actuator passage 14. It opens and closes in accordance with the internal pressure of the passage located upstream from the lock valve seat 14S in the direction from the hole 11 toward the actuator A. In the closed state, the lock valve 30 is configured to maintain a state of blocking the flow from the actuator A toward the spool hole 11.

  2, the valve body block 10 is locked at a position facing the lock valve seat 14S in the axial direction of the spool hole 11 (strictly, a direction parallel to the axial direction of the spool hole 11). It has a main body side mounting hole 14H for the valve 30. The main body side mounting hole 14H extends from the valve main body block 10 toward one side in the axial direction (strictly, a direction parallel to the axial direction of the spool hole 11). It penetrates outside. Further, a cover-side mounting hole 53 connected to the main-body-side mounting hole 14H is formed in the pilot chamber forming cover 50. The lock valve 30 in the present embodiment is attached to the valve body block 10 by being inserted in a state of straddling the body-side mounting hole 14H and the cover-side mounting hole 53. In the pilot chamber forming cover 50, a second input port 54 that opens to the cover-side mounting hole 53 is formed on the side opposite to the main body-side mounting hole 14H (see FIG. 1). The second input port 54 can receive hydraulic oil for applying pilot pressure to the lock valve 30.

  As shown in FIG. 2, the lock valve 30 is inserted into the main body side mounting hole 14 </ b> H and the cover side mounting hole 53, and the cylindrical casing 31 is arranged so that the axial direction thereof is parallel to the axial direction of the spool 20. An opening / closing poppet 32 provided slidably with respect to the cylindrical casing 31 on the lock valve seat 14S side of the cylindrical casing 31, a pilot poppet 33 slidably provided in an internal space 32S of the opening / closing poppet 32, A poppet-side spring 34 disposed in the internal space 32S and interposed between the open / close poppet 32 and the pilot poppet 33, and slidably provided on the cylindrical casing 31 on the pilot chamber forming cover 50 side of the cylindrical casing 31. Pilot piston 35 and pilot piston 35 A piston side spring 36 which imparts a biasing force for pushing back the chamber forming the cover 50 side, a has.

  The cylindrical casing 31 has an annular valve seat 31A that divides its internal space into two, and the open / close poppet 32 is provided in a space on the lock valve seat 14S side with respect to the annular valve seat 31A in the internal space of the cylindrical casing 31. Is provided. A pilot piston 35 is provided in a space on the pilot chamber forming cover 50 side with respect to the annular valve seat 31A in the internal space of the cylindrical casing 31.

  The opening / closing poppet 32 has a bottomed cylindrical shape with the bottom facing the lock valve seat 14S side, and has a bottom tapered toward the lock valve seat 14S. The opening / closing poppet 32 is exposed to the inside of the actuator passage 14 via the main body side mounting hole 14H, and the tapered bottom thereof is brought into contact with the lock valve seat 14S to close the actuator passage 14 while being separated from the lock valve seat 14S. To open the actuator passage 14. The bottom of the opening / closing poppet 32 is provided with a bottomed guide hole 32A formed on the center axis thereof and opening to the internal space 32S, and the pilot poppet 33 is held in the bottomed guide hole 32A and is provided in the annular valve seat 31A. Protruding toward.

  The pilot poppet 33 has a valve body tapering toward the annular valve seat 31A, and closes the opening by inserting the valve body into the opening of the annular valve seat 31A. The poppet-side spring 34 is disposed around a shaft portion located closer to the bottomed guide hole 32A than the valve body of the pilot poppet 33, and is prevented from coming off from the valve body block side. The poppet-side spring 34 applies an elastic force to the pilot poppet 33 to return the pilot poppet 33 to the annular valve seat 31A when the open / close poppet 32 is separated from the lock valve seat 14S. It is configured.

  A throttle hole 32B is formed at the bottom of the opening / closing poppet 32 and extends in the radial direction of the opening / closing poppet 32, opens to the bottomed guide hole 32A and opens to the actuator passage 14. The throttle hole 32B opens inside the passage of the actuator passage 14 located downstream of the open / close poppet 32 in the direction from the spool hole 11 to the actuator A. In both the case where the opening / closing poppet 32 opens and closes the lock valve seat 14S, the throttle hole 32B draws the hydraulic oil into the bottomed guide hole 32A side, and the inside of the cylindrical casing 31 through the internal space 32S. The hydraulic oil is sent to the

  On the other hand, the pilot piston 35 is provided in the internal space of the cylindrical casing 31 with the piston-side spring 36 disposed between the piston 35 and the annular valve seat 31A. The pilot piston 35 approaches the annular valve seat 31 </ b> A by receiving a pilot pressure due to the hydraulic oil flowing into the second input port 54 at an end opposite to the piston-side spring 36 side. . Here, a protrusion 35A is formed at the end of the annular valve seat 31A of the pilot piston 35, and the pilot piston 35 pushes the pilot poppet 33 by the protrusion 35A when receiving pilot pressure. Thus, the opening of the annular valve seat 31A is opened.

  In such a lock valve 30, when the pilot poppet 33 closes the opening of the annular valve seat 31 </ b> A, the operating oil is confined on the lock valve seat 14 </ b> S side of the internal space of the cylindrical casing 31, so that the opening and closing is performed. When the poppet 32 tries to separate from the lock valve seat 14S, the operating oil in the internal space of the cylindrical casing 31 prevents the opening and closing poppet 32 from separating, and the closed state of the lock valve 30 is maintained. Thereby, it is possible to maintain a state in which the flow in the direction from the actuator A toward the spool hole 11 is blocked. In the present embodiment, in a state in which the supply passages 12 and 13 and the actuator passage 14 are shut off (that is, a state in which hydraulic oil is not supplied to the actuator A), a pilot pressure is applied to the pilot piston 35. By not supplying the hydraulic oil to the second input port 54, the lock valve 30 maintains the closed state.

  On the other hand, when the pilot piston 35 pushes the pilot poppet 33 to open the opening of the annular valve seat 31A, the hydraulic oil flowing into the throttle hole 32B is subjected to the bottomed guide hole 32A, the internal space 32S, and the cylindrical shape. It flows into the pilot chamber forming cover 50 inside the cylindrical casing 31 via the lock valve seat 14S inside the cylindrical casing 31 and the annular valve seat 31A. This hydraulic oil is discharged to the outside through a lock valve side drain passage 31D formed in the cylindrical casing 31 and penetrating in the radial direction, and a valve body block side drain passage 10D formed in the valve body block 10. In the present embodiment, a part of the valve body block side drain passage 10D is formed on the outer periphery of the spool hole 11 and is open to the spool hole 11, and the hydraulic oil from the lock valve 30 bypasses the spool 20 and is discharged. Will be done.

  When the opening of the annular valve seat 31A is opened as described above, the operating oil in the internal space on the lock valve seat 14S side of the cylindrical casing 31 flows out. The drag received when trying to move away from 14S is reduced. Accordingly, the opening / closing poppet 32 is opened when the internal pressure of the passage portion of the actuator passage 14 located on the upstream side with respect to the lock valve seat 14S in the direction from the spool hole 11 toward the actuator A becomes higher than a predetermined pressure. become. In the present embodiment, the operating oil for applying the pilot pressure to the pilot piston 35 is supplied when at least the supply passages 12 and 13 are connected to the actuator passage 14 (that is, the operating oil is supplied to the actuator A). In this case, the power is supplied to the second input port 54.

  The relief valve 40 according to the present embodiment is provided outside the lock valve 30 in the radial direction of the spool 20 (or the spool hole 11) as shown in FIG. It is provided at a position overlapping the valve 30. The relief valve 40 is a valve that opens and closes according to the internal pressure of the actuator passage 14. More specifically, the pressure inside the passage located downstream of the lock valve 30 in the direction from the spool hole 11 to the actuator A in the actuator passage 14. Open and close according to.

  The relief valve 40 is provided in the valve body block 10, and opens and closes the discharge passage 100 provided in the valve body block 10 according to the internal pressure of the actuator passage 14. In the present embodiment, the discharge passage 100 includes an upstream portion 10G and a downstream portion 10E, and the relief valve 40 opens and closes a relief valve seat 40S as an opening and closing position formed between the upstream portion 10G and the downstream portion 10E. It is supposed to. The relief valve 40 has a cylindrical casing 41 and a valve body 42 slidably provided inside the casing 41, and the valve body 42 is always attached to the relief valve seat 40 </ b> S by a spring disposed in the casing 41. The relief valve seat 40S is closed by being urged. The axial directions of the cylindrical casing 41 and the valve body 42 are parallel to the axial directions of the spool 20 to the spool hole 11.

  The upstream portion 10G extends to one side in the spool axial direction from inside the passage located downstream of the lock valve 30 in the actuator passage 14, and then extends radially outward, and then further to one axial side Extends. The downstream portion 10E is connected to one end in the axial direction of the upstream portion 10G, extends toward the spool hole 11 inside the valve body block 10, and is connected to the tank passage 15. Specifically, the downstream portion 10E is connected to the opening of the tank passage 15 to the spool hole 11 from the outside in the radial direction of the spool hole 11. Thus, the downstream portion 10E connects the relief valve 40 and the tank passage 15 inside the valve body block 10, and connects the actuator passage 14 to the tank passage 15 via the relief valve 40 when the relief valve 40 is opened. It has become possible.

  FIG. 3 is a sectional view taken along line III-III in FIG. In the present embodiment, a part of the downstream portion 10E is formed by an annular passage portion 40R formed on the outer periphery of the lock valve 30, and the outer peripheral surface of the lock valve 30 defines the annular passage portion 40R. More specifically, the annular passage portion 40R is located on the valve body block 10 side of the cylindrical casing 31 of the lock valve 30 built in the valve body block 10 without being exposed to the actuator passage 14 in the lock valve 30. The outer peripheral surface of the cylindrical casing 31 defines the inner peripheral surface of the annular passage portion 40R. Further, as shown in FIG. 2, the outer peripheral surface of the cylindrical casing 31 defining the passage portion 40R is recessed radially inward with respect to the surrounding portion. Thus, in the present embodiment, it is possible to secure a large volume of the passage portion 40 </ b> R while suppressing the size of the valve body block 10.

  Next, an operation of a part of the direction switching valve device 1 according to the present embodiment will be described.

  In the direction switching valve device 1 according to the present embodiment, the supply passages 12 and 13 and the actuator passage 14 are shut off so that the hydraulic oil is not supplied to the actuator A. This state is formed by closing the opening of the downstream side supply passage 13 to the spool hole 11 by the land portion 20L of the spool 20 (see FIG. 1).

  At this time, in the lock valve 30, since the hydraulic oil for applying the pilot pressure to the pilot piston 35 is not supplied to the second input port 54, the pilot poppet 33 closes the opening of the annular valve seat 31A. The closed state is maintained, and a state is formed in which the operating oil is confined on the lock valve seat 14S side of the internal space of the cylindrical casing 31. Accordingly, when the opening / closing poppet 32 attempts to separate from the lock valve seat 14S, the locked hydraulic oil prevents separation of the opening / closing poppet 32, thereby maintaining the closed state of the lock valve 30. As described above, the cutoff state of the flow in the direction from the actuator A to the spool hole 11 is maintained, and even if the hydraulic oil tries to flow backward from the actuator A side to the spool hole 11, the hydraulic oil is prevented from flowing into the spool hole 11. Therefore, undesired movement of the actuator A is suppressed.

  On the other hand, in the state where the lock valve 30 is maintained in the closed state as described above, for example, when the pressure of the hydraulic oil becomes excessively large due to the abnormality, the hydraulic oil is supplied to the valve body of the relief valve 40. 42 is pushed toward the casing 41 to separate the valve body 42 from the relief valve seat 40S. As a result, the relief valve 40 opens to discharge the hydraulic oil to the tank passage 15. When the relief valve 40 is opened, the hydraulic oil from the actuator passage 14 reaches the tank passage 15 via the discharge passage 100 inside the valve body block 10, and is thereafter discharged to the tank T. As a result, in the present embodiment, it is possible to avoid damage to the actuator passage 14, the actuator A, the piping connecting them, and the like due to abnormally high pressure.

  In the direction switching valve device 1 according to the present embodiment described above, the discharge passage 100 of the relief valve 40 for discharging the hydraulic oil when the relief valve 40 is opened is connected to the tank passage 15 in the valve body block 10. Connected. This simplifies the structure of the discharge passage 100 as compared with the conventional structure in which the discharge path of the relief valve needs to be configured in cooperation with another direction switching valve device. Further, when the directional control valve device 1 is used together with another directional control valve device, the restriction on the arrangement of the directional control valve device 1 caused by the other directional control valve device is relaxed. Therefore, the discharge passage 100 in which the relief valve 40 opens and closes can be connected to the tank T without complication, and the degree of freedom of arrangement of the directional control valve device 1 when used together with another directional control valve device is improved. Can be done.

  Further, the lock valve 30 in the present embodiment is provided between the spool 20 and the relief valve 40 in the radial direction of the spool 20, and a part of the discharge passage 100 is formed in an annular shape formed on the outer periphery of the lock valve 30. And the outer peripheral surface of the lock valve 30 defines an annular passage portion 40R. This effectively suppresses the length of the discharge passage 100 particularly when the discharge passage 100 is connected to the opening of the tank passage 15 to the spool hole 11 from the outside in the radial direction of the spool hole 11. By doing so, it is possible to suppress an increase in the size of the direction switching valve device 1 due to the formation of the discharge passage 100.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various changes may be made in the above embodiments.

DESCRIPTION OF SYMBOLS 1 ... Direction switching valve device 10 ... Valve body block 11 ... Spool hole 12 ... Upstream supply passage 13 ... Downstream supply passage 14 ... Actuator passage 14S ... Lock valve seat 15 ... Tank passage 20 ... Spool 30 ... Lock valve 31 ... Cylindrical -Shaped casing 31A-annular valve seat 31D-lock valve side drain passage 32-opening and closing poppet 32A-bottomed guide hole 32B-throttle hole 33-pilot poppet 34-poppet side spring 35-pilot piston 35A-convex part 36 ... Piston side spring 40 Relief valve 40S Relief valve seat 40R Annular passage portion 41 Casing 42 Valve element 100 Discharge passage P Pump A Actuator T Tank

Claims (5)

A spool hole, an actuator passage opening to the spool hole and connected to an actuator, a tank passage opening to the spool hole and connected to a tank, and a discharge passage connecting the actuator passage and the tank passage are provided. A valve body block,
A spool,
A lock valve for opening and closing the actuator passage at a predetermined opening / closing position set in the actuator passage, wherein the internal pressure of a passage portion located upstream with respect to the opening / closing position in a direction from the spool hole toward the actuator is reduced. A lock valve that opens and closes in response to maintaining a shut-off state of a flow in a direction from the actuator toward the spool hole in a closed state;
A relief valve that opens and closes the discharge passage in accordance with the internal pressure of the actuator passage. The lock valve is provided between the spool and the relief valve in a radial direction of the spool,
Part of the discharge passage is formed by an annular passage portion formed on an outer periphery of a portion of the lock valve that is not exposed to the actuator passage,
The directional switching valve device according to claim 1, wherein an outer peripheral surface of the lock valve defines the annular passage portion.   3. The relief valve according to claim 1, wherein the relief valve opens and closes in response to a pressure inside a passage located downstream of the lock valve in a direction from the spool hole to the actuator in the actuator passage. 4. The directional switching valve device according to claim 1. The valve body block includes a supply passage that opens to the spool hole and is connected to a pump.
The spool connects the supply passage and the actuator passage and shuts off the actuator passage and the tank passage, or shuts off the supply passage and the actuator passage according to the position of the spool. 4. The method according to claim 1, wherein the actuator path and the tank path are cut off, or the actuator path and the tank path are connected and the supply path and the actuator path are cut off. 5. Directional valve device. A directional switching valve device,
A spool hole, an actuator passage opening to the spool hole and connected to an actuator, a tank passage opening to the spool hole and connected to a tank, and a discharge passage connecting the actuator passage and the tank passage are provided. A valve body block,
A spool,
A lock valve that opens and closes the actuator passage at a predetermined opening and closing position set in the actuator passage,
And a relief valve,
The lock valve closes the actuator passage in accordance with an internal pressure of a passage portion located on an upstream side with respect to the opening / closing position in a direction from the spool hole toward the actuator, and closes the actuator passage in a direction from the actuator toward the spool hole. Shut off the flow,
The direction switching valve device, wherein the relief valve opens the discharge passage according to an internal pressure of the actuator passage.