JP7134788B2 - Direction switching valve device - Google Patents

Description

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

Construction machinery usually controls moving parts such as arms and booms by directional switching valve devices, and the directional switching valve devices used in such construction machinery generally include a valve body having a spool hole and a slide valve on the spool hole. A freely provided spool is provided, and by moving the spool in the valve body, supply and cutoff of hydraulic oil are switched.

When the directional switching valve device as described above controls the operation of the arm or boom of the construction machine, a hydraulic cylinder is provided between the directional switching valve device and the arm or boom, and the hydraulic oil from the directional switching valve device Arms and booms are driven by telescopic hydraulic cylinders. Here, when a situation arises in which the arm or boom is held stationary, the directional switching valve device cuts off the connection with the pump, which is the supply source of the hydraulic oil, and also the destination of the hydraulic oil returning from the hydraulic cylinder. It is switched to the state of cutting off the connection with the tank that becomes

However, in a directional switching valve device for a heavy arm or boom, hydraulic fluid may not pass between the spool and the inner peripheral surface of the spool hole due to the effect of the weight of the arm or boom only by shutting off the pump and the tank. This creates a situation where it is difficult to hold the arm or boom stationary. Therefore, a directional switching valve device for an arm or boom is usually provided with a lock valve for preventing leakage of hydraulic oil.

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

Various techniques related to the directional switching valve device provided with the lock valve and the relief valve as described above have been conventionally proposed. The structure provided is disclosed.

Japanese Utility Model Publication No. 7-47604

In construction machinery, generally, a plurality of directional switching valve devices corresponding to a plurality of operating portions are stacked to form a unit, and the unit is incorporated therein. Although Patent Document 1 does not disclose a detailed structure of a passage for discharging hydraulic oil when a relief valve provided in the directional switching valve device is opened, this directional switching valve device is similar to other directional switching valve devices. On the premise that it is arranged overlapping with, the hydraulic oil discharge passage is connected to the passage formed in the other adjacent directional switching valve device and the tank passage, and through these passages to the tank It is considered to have structures that are connected.

However, in the above structure, a seal mechanism is required at the passage connecting portion between the adjacent directional switching valve devices, which complicates the structure. Also, the directional switching valve device provided with the relief valve and the other directional switching valve device having a passage connected to the hydraulic oil discharging passage formed in this directional switching valve must be adjacent to each other. The flexibility of arranging multiple directional valve devices is restricted because they need to be arranged and fastened together.

Specifically, the other directional switching valve device is preferably one that can easily secure a space for forming a passage connected to the hydraulic oil discharge passage. It may be a directional switching valve device for In this case, in a unit composed of a plurality of directional switching valve devices, the directional switching valve device for the arm or boom and the directional switching valve device for the revolving section must be adjacent to each other. The degree of freedom in arranging the valve devices is restricted.

The present invention has been made in consideration of the above-mentioned circumstances, and can be connected to the tank without complicating the discharge passage opened and closed by the relief valve, and the arrangement when used with other directional switching valve devices. An object of the present invention is to provide a directional switching valve device capable of improving the degree of freedom.

A directional switching valve device according to the present invention comprises a spool hole, an actuator passage opening in the spool hole and connected to an actuator, a tank passage opening in 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 open/close position set in the actuator passage, the lock valve extending from the spool hole toward the actuator. a lock valve that opens and closes according to the internal pressure of a passage portion located upstream with respect to the open/close position in the direction of the open/closed position, and maintains a blocked state of flow in the direction from the actuator toward the spool hole in the closed state; and a relief valve that opens and closes the actuator passage according to the internal pressure of the actuator passage. is.

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

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

The valve body block further includes a supply passage that opens to the spool hole and is connected to the pump, and the spool connects the supply passage and the actuator passage and the actuator passage and or the supply passage and the actuator passage are blocked and the actuator passage and the tank passage are blocked, or the actuator passage and the tank passage are connected and The supply passage and the actuator passage may be blocked.

Further, the directional switching valve device according to the present invention includes a spool hole, an actuator passage opening in the spool hole and connected to an actuator, a tank passage opening in 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/closing position set in the actuator passage; and a relief valve; The lock valve closes the actuator passage according to the internal pressure of a passage portion positioned upstream with respect to the open/close position in the direction from the spool hole to the actuator, and closes the actuator passage in the direction from the actuator to the spool hole. Blocking flow, the relief valve is a directional valve arrangement that opens the exhaust passage in response to internal pressure in the actuator passage.

According to the directional switching valve device of the present invention, it is possible to connect to the tank without complicating the discharge passage that the relief valve opens and closes, and to increase the degree of freedom of arrangement when used together with other directional switching valve devices. can be improved.

1 is a cross-sectional view of a directional switching valve device according to an embodiment of the present invention; FIG. FIG. 2 is an enlarged cross-sectional view of a lock valve provided in the directional switching valve device shown in FIG. 1; FIG. 2 is a cross-sectional view taken along line III-III of FIG. 1;

A directional switching valve device 1 according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a directional switching valve device 1 according to this embodiment. In FIG. 1, only a partial cross section of the directional switching valve device 1 is shown for convenience of explanation. The directional switching valve device 1 is a valve that controls the flow of hydraulic fluid supplied from the pump P to the actuator A and hydraulic fluid discharged from the actuator A to the tank T. As shown in FIG.

In this embodiment, the directional switching valve device 1 is configured to supply the hydraulic oil from the pump P to the actuator A (specifically, the hydraulic cylinder) for operating the arm or boom of the construction machine. . However, such a configuration is only 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 directional 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. I have.

The valve body block 10 is, for example, a flat rectangular block, 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 opens outward from the plane portion of the valve body block 10 along its 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 its axial direction.

The slide drive system in the axial direction of the spool 20 is not particularly limited, and as the drive system, for example, a mechanical, hydraulic pilot, or electromagnetic drive structure may be adopted, but in the present embodiment, the hydraulic pilot system is used. Adopted.

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

The spool 20 has a plurality of land portions 20L spaced apart from each other in the axial direction and a plurality of cutout portions 20N provided between the land portions 20L. In FIG. 1, the outer diameter of each land portion 20L substantially matches the inner diameter of the spool hole 11. As shown in FIG. On the other hand, the outer diameter of each notch 20N is smaller than the inner diameter of the spool hole 11. As shown in FIG.

When the land portion 20L straddles the openings of two passages, which will be described later, opening into the spool hole 11, and is arranged so as to block the entire openings, the flow of hydraulic oil between these two passages is blocked. . On the other hand, the notch 20N forms a passage that connects these two passages and allows the hydraulic oil to flow when it is arranged so as to straddle the openings described above. The spool 20 can not only switch between connection and disconnection (that is, connection/non-connection) between the passages, but also can adjust the passage opening (that is, the valve opening) between the passages according to the position.

In addition to the spool hole 11 , the valve body block 10 includes 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 the hydraulic oil supplied from the pump P flows into the downstream supply passage 13 via the check valve 61 . Specifically, when hydraulic fluid from the pump P opens the check valve 61, the upstream supply passage 12 and the downstream supply passage 13 are connected, and hydraulic fluid flows from the upstream supply passage 12 to the downstream supply passage 13. influx.

The upstream supply passage 12 is a hole that extends radially outside the spool hole 11 without directly intersecting the spool hole 11, and has a check mark at the radially outer end forming the outlet thereof. It forms the valve seat of the valve 61 and is connected to the downstream supply passage 13 via this valve seat. The downstream supply passage 13 extends so as to approach the spool hole 11 as it progresses toward one axial side of the spool hole 11 from the connection position with the upstream supply passage 12 .

The downstream supply passage 13 is a passage for supplying the hydraulic oil that has flowed 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 opening of the downstream supply passage 13 to the spool hole 11 is blocked by the land portion 20L of the spool 20 (state shown in FIG. 1), the gap between the spool hole 11 and the actuator passage 14 and the downstream supply passage 13 The connection is cut off or the valve opening is restricted. The supply passage in the present invention is a portion corresponding to the upstream supply passage 12 and the downstream supply passage 13 in this 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 located on one side of the downstream supply passage 13 in the axial direction of the spool hole 11 and is close 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 .

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

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 hydraulic oil discharged from the actuator A to the tank T. As shown in FIG. The tank passage 15 is connected to the actuator passage 14 or disconnected from the actuator passage 14 depending on the position of the spool 20 .

The tank passage 15 in the present embodiment has its 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 , while the opening to this spool hole 11 is positioned. It extends from the opening to the other axial side of the spool hole 11 . As a result, 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 of the spool hole 11 in the axial direction through the opening of the tank passage 15 to the spool hole 11. It will flow and then be discharged.

The directional switching valve device 1 having the above-described configuration can operate in a first state in which the supply passages 12 and 13 are connected to the actuator passage 14 and a state in which the supply passages 12 and 13 are connected according to the position of the spool 20 in the spool hole 11 . and the actuator passage 14 are shut off, and a third state is possible in which the actuator passage 14 and the tank passage 15 are connected. 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 blocked. In the second state, the supply passages 12, 13 and the actuator passage 14 are blocked and the actuator passage 14 and the tank passage 15 are blocked. 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 blocked.

Here, in the present embodiment, as described above, a hydraulic pilot type driving structure is adopted as the driving method of the spool 20. This structure is an opening on one side of the spool hole 11 in the valve body block 10 in the axial direction. A pilot chamber forming cover 50 and the like provided on one side of the spool hole 11 in the axial direction with respect to the end portion of the spool 20 facing the outside from the valve body block 10 .

The pilot chamber forming cover 50 has a spool pilot chamber 51 and is attached to the valve body block 10 so as to connect the spool pilot chamber 51 to the opening on one side of the spool hole 11 in the valve body block 10 in the axial direction. Fixed. The pilot chamber formation cover 50 is formed with a first input port 52 that opens to the spool pilot chamber 51 on the side opposite to the spool hole 11 side. As a result, the hydraulic oil flows into the first input port 52, so that the pilot pressure can be applied to the end portion of the spool 20 facing the outside from the opening on one side of the spool hole 11 in the axial direction. On the other hand, although not shown, the end of the spool 20 opposite to the end on which the pilot pressure acts is biased toward the spool pilot chamber 51 by a spring. Thus, in the hydraulic pilot type drive structure according to 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 explained. 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), particularly 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 at the lock valve seat 14S (corresponding to the predetermined opening/closing position referred to in the present invention) set in the actuator passage 14. It opens and closes according to the internal pressure of the passage portion positioned upstream with respect to the lock valve seat 14S in the direction from the hole 11 toward the actuator A. Further, the lock valve 30 is configured to keep the flow in the direction from the actuator A toward the spool hole 11 blocked in the closed state.

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 speaking, the direction parallel to the axial direction of the spool hole 11). It has a body-side mounting hole 14H for the valve 30, and this body-side mounting hole 14H extends from the valve body block 10 toward one side in the axial direction (strictly speaking, the direction parallel to the axial direction of the spool hole 11). penetrates to the outside. Further, the pilot chamber forming cover 50 is formed with a cover-side mounting hole 53 connected to the main body-side mounting hole 14H. The lock valve 30 in the present embodiment is attached to the valve body block 10 by being inserted across the body side attachment hole 14H and the cover side attachment hole 53 . Further, the pilot chamber forming cover 50 is formed with a second input port 54 that opens into the cover-side mounting hole 53 on the side opposite to the body-side mounting hole 14H (see FIG. 1). The second input port 54 can receive hydraulic fluid for applying pilot pressure to the lock valve 30 .

As shown in FIG. 2, the lock valve 30 is inserted into the body-side mounting hole 14H and the cover-side mounting hole 53, and has a cylindrical casing 31 arranged so that its axial direction 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 provided slidably in the inner 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 a poppet-side spring 34 provided slidably with respect to the cylindrical casing 31 on the side of the pilot chamber forming cover 50 in the cylindrical casing 31. It has a pilot piston 35 and a piston-side spring 36 that imparts an urging force to push the pilot piston 35 back toward the pilot chamber formation cover 50 side.

The cylindrical casing 31 has an annular valve seat 31A that divides its internal space into two. is provided. A pilot piston 35 is provided in a space of the inner space of the cylindrical casing 31 on the side of the pilot chamber forming cover 50 with respect to the annular valve seat 31A.

The open/close poppet 32 has a cylindrical shape with a bottom facing toward the lock valve seat 14S, and has a bottom portion that tapers toward the lock valve seat 14S. The open/close poppet 32 is exposed in the actuator passage 14 through the body-side mounting hole 14H, and its tapered bottom portion contacts the lock valve seat 14S to close the actuator passage 14 while separating from the lock valve seat 14S. , the actuator passage 14 is opened. A bottomed guide hole 32A is formed on the bottom of the opening/closing poppet 32 and opens into an internal space 32S. protruding towards.

The pilot poppet 33 has a valve body that tapers toward the annular valve seat 31A, and the valve body is inserted into the opening of the annular valve seat 31A to close the opening. The poppet-side spring 34 is arranged around the shaft portion located on the bottomed guide hole 32A side of the valve body portion 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 side when the open/close poppet 32 is separated from the lock valve seat 14S. It is configured.

A throttle hole 32B extending in the radial direction of the open/close poppet 32 and opening to the bottomed guide hole 32A and opening to the actuator passage 14 is formed at the bottom of the open/close poppet 32 . The throttle hole 32</b>B opens inside the actuator passage 14 located downstream of the open/close poppet 32 in the direction from the spool hole 11 toward the actuator A. In both states in which the open/close poppet 32 opens and closes the lock valve seat 14S, the restrictor hole 32B draws hydraulic oil into the bottomed guide hole 32A side, and flows into the cylindrical casing 31 through the inner space 32S. It is designed to send hydraulic oil to

On the other hand, the pilot piston 35 is provided in the internal space of the cylindrical casing 31 with a piston-side spring 36 interposed between the pilot piston 35 and the annular valve seat 31A. The pilot piston 35 approaches the annular valve seat 31A by receiving the pilot pressure from the hydraulic oil that has flowed into the second input port 54 at the end on the side opposite to the piston-side spring 36 side. . A convex portion 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 convex portion 35A when receiving pilot pressure. , thereby opening the opening of the annular valve seat 31A.

In such a lock valve 30, when the pilot poppet 33 closes the opening of the annular valve seat 31A, hydraulic oil is confined in the inner space of the cylindrical casing 31 on the side of the lock valve seat 14S. When the poppet 32 tries to separate from the lock valve seat 14S, the hydraulic oil in the internal space of the cylindrical casing 31 prevents the separation of the open/close poppet 32, and the lock valve 30 is maintained in the closed state. As a result, it is possible to maintain the blocking state of the flow in the direction from the actuator A toward the spool hole 11 . In the present embodiment, in a state in which the supply passages 12 and 13 and the actuator passage 14 are cut off (that is, in a state in which the hydraulic oil is not supplied to the actuator A), the pilot pressure is applied to the pilot piston 35. By not supplying hydraulic fluid to the second input port 54, the lock valve 30 is kept closed.

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 flows through the bottomed guide hole 32A, the internal space 32S, and the cylindrical valve seat 32S. It flows into the pilot chamber formation cover 50 side inside the cylindrical casing 31 via the lock valve seat 14S side and the annular valve seat 31A inside the cylindrical casing 31 . The hydraulic oil is discharged to the outside through a lock valve side drain passage 31D formed in the cylindrical casing 31 and a valve body block side drain passage 10D formed in the valve body block 10, which penetrates in the radial direction. In the present embodiment, a portion of the valve body block side drain passage 10D is formed on the outer periphery of the spool hole 11 and opens into the spool hole 11, and hydraulic oil from the lock valve 30 bypasses the spool 20 and is discharged. will be

As described above, when the opening of the annular valve seat 31A is opened, the hydraulic oil in the inner space of the cylindrical casing 31 on the lock valve seat 14S side flows out. The drag received when trying to separate from 14S is reduced. As a result, the opening/closing poppet 32 is opened when the internal pressure of the passage portion of the actuator passage 14 positioned upstream of the lock valve seat 14S in the direction from the spool hole 11 toward the actuator A reaches or exceeds a predetermined pressure. become. In this embodiment, hydraulic fluid for applying pilot pressure to the pilot piston 35 is supplied at least when the supply passages 12 and 13 and the actuator passage 14 are connected (that is, hydraulic fluid is supplied to the actuator A). ) is supplied to the second input port 54 .

Relief valve 40 will be described. Relief valve 40 in the present embodiment is provided radially outside lock valve 30 of spool 20 (or 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 in the actuator passage 14 toward the actuator A. Opens and closes accordingly.

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 this 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/closing position formed between the upstream portion 10G and the downstream portion 10E. It is designed to The relief valve 40 has a cylindrical casing 41 and a valve body 42 slidably provided inside the casing 41. A spring arranged in the casing 41 always keeps the valve body 42 on the relief valve seat 40S. The relief valve seat 40S is closed by biasing. 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 from the inside of the actuator passage 14 downstream of the lock valve 30 to one side in the spool axial direction, then extends radially outward, and then further extends to the one axial side. extends to The downstream portion 10</b>E is connected to one axial end of the upstream portion 10</b>G, extends toward the spool hole 11 inside the valve body block 10 , and is connected to the tank passage 15 . Specifically, the downstream portion 10</b>E connects to the opening of the tank passage 15 to the spool hole 11 from the radially outer side of the spool hole 11 . Thereby, 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 is possible.

FIG. 3 is a cross-sectional view taken along line III--III in FIG. In this embodiment, 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. As a result, in the present embodiment, it is possible to secure a large volume of the passage portion 40R while suppressing the size of the valve body block 10. As shown in FIG.

Next, a partial operation of the directional switching valve device 1 according to this embodiment will be described.

In the directional 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 supply passage 13 to the spool hole 11 with the land portion 20L of the spool 20 (see FIG. 1).

At this time, in the lock valve 30, the hydraulic oil for applying the pilot pressure to the pilot piston 35 is not supplied to the second input port 54, so that the pilot poppet 33 closes the opening of the annular valve seat 31A. The closed state is maintained, and a state is created in which the hydraulic oil is confined on the lock valve seat 14S side of the inner space of the cylindrical casing 31 . As a result, when the opening/closing poppet 32 attempts to separate from the lock valve seat 14S, the trapped hydraulic oil prevents the opening/closing poppet 32 from separating, thereby maintaining the lock valve 30 in the closed state. As described above, the blockage state of the flow in the direction from the actuator A toward the spool hole 11 is maintained, and even if the hydraulic oil tries to flow back from the actuator A side to the spool hole 11 side, the hydraulic oil is prevented from flowing into the spool hole 11. Therefore, the actuator A is prevented from moving undesirably.

On the other hand, in the state where the lock valve 30 is maintained in the closed state as described above, for example, if the pressure of the hydraulic oil becomes excessively high due to an abnormality, the hydraulic oil is forced into the valve body of the relief valve 40. 42 is pushed toward the casing 41 side to separate the valve element 42 from the relief valve seat 40S. As a result, the relief valve 40 is opened and the working oil is discharged to the tank passage 15 . When the relief valve 40 is opened, hydraulic fluid from the actuator passage 14 reaches the tank passage 15 through the discharge passage 100 inside the valve body block 10, and then is 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, and the piping connecting them due to abnormally high pressure.

In the directional switching valve device 1 according to the present embodiment described above, the discharge passage 100 of the relief valve 40 for discharging 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 compared to the conventional structure in which the discharge path of the relief valve had to be configured in cooperation with other directional switching valve devices. Furthermore, when the directional switching valve device 1 is used together with other directional switching valve devices, restrictions on the arrangement of the directional switching valve device 1 caused by the other directional switching valve devices are alleviated. Therefore, the discharge passage 100 opened and closed by the relief valve 40 can be connected to the tank T without complication, and the directional switching valve device 1 can be arranged more freely when used together with other directional switching valve devices. can be made

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 an annular valve 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 reduces the length of the discharge passage 100 particularly when connecting the discharge passage 100 to the opening of the tank passage 15 to the spool hole 11 from the radially outer side of the spool hole 11. can suppress an increase in the size of the directional 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-described embodiments, and various modifications may be made to the above-described embodiments.

Reference Signs List 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 Casing 31A Annular valve seat 31D Lock valve side drain passage 32 Open/close poppet 32A Bottomed guide hole 32B Throttle hole 33 Pilot poppet 34 Poppet side spring 35 Pilot piston 35A Convex portion 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 (4)

A spool hole, an actuator passage opening in the spool hole and connected to an actuator, a tank passage opening in the spool hole and connected to a tank, and a discharge passage connecting the actuator passage and the tank passage. a valve body block;
a spool;
A lock valve that opens and closes the actuator passage at a predetermined open/close position set in the actuator passage, wherein the internal pressure of the passage portion positioned upstream of the open/close position in the direction from the spool hole toward the actuator. a lock valve that opens and closes accordingly and maintains a state of blocking flow in a direction from the actuator toward the spool hole in the closed state;
a relief valve that opens and closes the discharge passage according to the internal pressure of the actuator passage ,
The lock valve is provided between the spool and the relief valve in the radial direction of the spool,
The discharge passage includes a portion extending from the relief valve toward the spool hole,
A portion of the discharge passage extending from the relief valve toward the spool hole is formed by an annular passage formed on the outer periphery of a portion of the lock valve that is not exposed to the actuator passage. has been
The lock valve is arranged in parallel with the axial direction of the spool, and includes a cylindrical casing having an annular valve seat that divides the internal space into two, and the annular valve seat in the internal space of the cylindrical casing. an open/close poppet provided in a space on the open/close position side with respect to the valve seat and slidable relative to the cylindrical casing ;
The opening/closing poppet has a bottomed cylindrical shape with a bottom facing the opening/closing position, is exposed to the actuator passage, and closes the actuator passage by bringing the bottom into contact with the opening/closing position,
The opening/closing poppet maintains the lock valve in a closed state by closing the annular valve seat, and moves away from the opening/closing position to open the lock valve by opening the annular valve seat. ,
The directional switching valve device , wherein the cylindrical casing is a portion that is not exposed to the actuator passage, and an outer peripheral surface of the cylindrical casing defines the annular passage portion . 2. The relief valve according to claim 1 , wherein said relief valve opens and closes according to the pressure inside said actuator passage located downstream of said lock valve in the direction from said spool hole toward said actuator. Directional switching valve device. The valve body block has a supply passage that opens to the spool hole and is connected to the pump,
Depending on the position of the spool, the spool connects the supply passage and the actuator passage and blocks the actuator passage and the tank passage, or blocks the supply passage and the actuator passage. 3. The direction switching according to claim 1, wherein the actuator passage and the tank passage are blocked, or the actuator passage and the tank passage are connected and the supply passage and the actuator passage are blocked. valve device. A directional switching valve device,
A spool hole, an actuator passage opening in the spool hole and connected to an actuator, a tank passage opening in the spool hole and connected to a tank, and a discharge passage connecting the actuator passage and the tank passage. a valve body block;
a spool;
a lock valve that opens and closes the actuator passage at a predetermined open/close position set in the actuator passage;
a relief valve;
The lock valve closes the actuator passage according to the internal pressure of a passage portion positioned upstream with respect to the open/close position in the direction from the spool hole to the actuator, and closes the actuator passage in the direction from the actuator to the spool hole. blocking flow, the relief valve opening the discharge passage in response to the internal pressure of the actuator passage;
The lock valve is provided between the spool and the relief valve in the radial direction of the spool,
The discharge passage includes a portion extending from the relief valve toward the spool hole,
A portion of the discharge passage extending from the relief valve toward the spool hole is formed by an annular passage formed on the outer circumference of a portion of the lock valve that is not exposed to the actuator passage. has been
The lock valve is arranged in parallel with the axial direction of the spool, and includes a cylindrical casing having an annular valve seat that divides the internal space into two, and the annular valve seat in the internal space of the cylindrical casing. an open/close poppet provided in a space on the open/close position side with respect to the valve seat and slidable relative to the cylindrical casing;
The open/close poppet has a bottomed cylindrical shape with a bottom portion facing the open/close position side, is exposed to the actuator passage, and closes the actuator passage by bringing the bottom portion into contact with the open/close position,
The opening/closing poppet maintains the lock valve in a closed state by closing the annular valve seat, and moves away from the opening/closing position to open the lock valve by opening the annular valve seat. ,
The directional switching valve device , wherein the cylindrical casing is a portion that is not exposed to the actuator passage, and an outer peripheral surface of the cylindrical casing defines the annular passage portion .

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