JP7220520B2 - spool valve - Google Patents

Description

TECHNICAL FIELD The present invention relates to a spool valve having a response delay prevention function and a shockless function.

2. Description of the Related Art Conventionally, in a hydraulic circuit that drives and controls an actuator such as a hydraulic cylinder used in construction machinery such as a hydraulic excavator, it is known to provide a shockless valve in order to prevent the occurrence of shock when the actuator stops operating. there is FIG. 8 shows an example of a hydraulic circuit using a conventional shockless valve.

A hydraulic circuit 1 shown in FIG. and have The hydraulic circuit 1 also has a pilot control valve (hereinafter referred to as a remote control valve) 4 for controlling the operation of the spool valve 3 , a pilot hydraulic pressure source 6 and a tank 7 . Furthermore, the hydraulic circuit 1 has a shockless valve 20 .

In the illustrated example, the actuator 2 is a hydraulic cylinder having a piston rod 2r, and has a head-side oil chamber 2a and a rod-side oil chamber 2b. A head-side port and a rod-side port are provided in the head-side oil chamber 2a and the rod-side oil chamber 2b, respectively.

The spool valve 3 has a valve body block (not shown) and a spool 31 extending in one direction (horizontal direction in FIG. 8). The spool 31 is accommodated in a spool hole formed in the valve body block. The spool valve 3 has an oil supply port communicating with the main hydraulic pressure source 5 and an oil drain port communicating with the tank 7 . The spool valve 3 changes the connection state between the oil supply port and oil drain port of the spool valve 3 and the head side port and rod side port of the actuator 2 according to the position of the spool 31 .

The spool valve 3 includes pilot pressure acting portions 32a and 32b at one side end and the other side end of the one direction. The pilot pressure acting portions 32 a and 32 b are means for applying pilot pressure to the ends of the spool 31 for the purpose of driving the spool 31 . By applying a pilot pressure to one side end of the spool 31 in the one direction, the spool 31 is moved from the neutral position shown in FIG. It can be moved into the operating position. Further, by applying a pilot pressure to the other side end of the spool 31 in the one direction, the spool 31 is moved from the neutral position shown in FIG. 8 to one side in the one direction (rightward in FIG. 8). It can be moved to a second operating position.

The spool valve 3 also has a spring 13 that applies elastic force to the spool 31 in the one direction. The spring 13 holds the spool 31 at the neutral position shown in FIG.

When the spool 31 is in the neutral position, the oil supply port and the oil discharge port of the spool valve 3 are not connected to any port of the actuator 2 (see FIG. 8), and pressure oil is supplied to the actuator 2. No evacuation takes place. On the other hand, when the spool 31 is in the first operating position, the oil supply port and the oil drain port of the spool valve 3 are connected to the head side port and the rod side port of the actuator 2, respectively. As a result, the main hydraulic pressure source 5 and the head-side oil chamber 2a communicate with each other through the spool valve 3, and the rod-side oil chamber 2b and the tank 7 communicate with each other. Oil is supplied and discharged. Also, when the spool 31 is in the second operating position, the oil supply port and the oil drain port of the spool valve 3 are connected to the rod side port and the head side port of the actuator 2, respectively. As a result, the main hydraulic source 5 and the rod-side oil chamber 2b communicate with each other through the spool valve 3, and the head-side oil chamber 2a and the tank 7 communicate with each other. is supplied and discharged. In this manner, the actuator 2 can be driven as desired by changing the connection state between the oil supply port and oil discharge port of the spool valve 3 and the port of the actuator 2 .

The remote control valve 4 is a valve for controlling the pilot pressure described above. Pilot lines 11 and 12 are connected to the pilot pressure acting portions 32a and 32b of the spool valve 3, respectively. The remote control valve 4 causes the pilot lines 11 and 12 on the side corresponding to the operating direction of the control lever 4a to communicate with the pilot hydraulic pressure source 6 to supply pressure oil to the pilot lines 11 and 12 . As a result, pilot pressure is generated in the pilot pressure acting portions 32 a and 32 b connected to the pilot lines 11 and 12 . When the remote control valve 4 connects the pilot lines 11 and 12 with the pilot hydraulic pressure source 6, the other pilot lines 12 and 11 and the tank 7 are connected with each other. Also, when the operating lever 4 a is not operated, the remote control valve 4 allows both pilot lines 11 and 12 to communicate with the tank 7 .

The shockless valve 20 is provided as a separate valve from the spool valve 3 and the remote control valve 4 at a position on the pilot line 11 between the remote control valve 4 and one pilot pressure acting portion 32a. The shockless valve 20 has a throttle 21 arranged on the pilot line 11 and a detour 22 having both ends connected to the pilot line 11 on both sides of the throttle 21 . A check valve 23 is provided in the detour 22 . The check valve 23 allows pressure oil to flow from the remote control valve 4 side to the pilot pressure acting portion 32a side of the spool valve 3, while allowing pressure oil to flow from the pilot pressure acting portion 32a side to the remote control valve 4 side. It is configured to prevent the inflow of oil. Such a shockless valve 20 does not limit the flow rate of pressure oil directed from the remote control valve 4 to the pilot pressure acting portion 32a per unit time. limit the flow of

Next, the action of the hydraulic circuit 1 shown in FIG. 8 will be described.

First, when the operating lever 4a of the remote control valve 4 is not operated, both the pilot lines 11 and 12 communicate with the tank 7. As shown in FIG. Therefore, no pilot pressure is generated in any of the pilot pressure acting portions 32a and 32b, and the spool 31 is held at the neutral position shown in FIG.

In order to move the spool 31 from the neutral position to the first operating position, the operating lever 4a of the remote control valve 4 is operated to bring the pilot line 11 and the pilot hydraulic pressure source 6 into communication. As a result, pressure oil is supplied from the pilot hydraulic pressure source 6 to the pilot line 11 . The pressure oil supplied to the pilot line 11 passes through the shockless valve 20 and flows into the pilot pressure acting portion 32a. The shockless valve 20 does not limit the flow rate per unit time of pressure oil flowing into the pilot pressure acting portion 32a. Therefore, a pilot pressure corresponding to the amount of operation of the operating lever 4a is immediately generated in the pilot pressure acting portion 32a, and the spool 31 immediately moves from the neutral position to the first operating position at a speed corresponding to the amount of operation of the operating lever 4a. Moving. Therefore, the actuator 2 operates without delay in response to the operation of the operating lever 4a.

Next, in order to move the spool 31 from the first operating position to the neutral position, the control lever 4a of the remote control valve 4 is operated to connect the pilot line 11 to the tank 7. As a result, the pilot pressure in the pilot line 11 disappears. Then, the pressure oil in the pilot pressure acting portion 32a flows in the direction toward the remote control valve 4, and along with this, the spool 31 starts moving to the neutral position. Here, the shockless valve 20 limits the flow rate per unit time of pressure oil that flows from the pilot pressure acting portion 32 a toward the remote control valve 4 . Therefore, the spool 31 moves slowly from the first operating position to the neutral position. This prevents the actuator 2 from suddenly stopping due to the sudden movement of the spool 31 . As a result, it is possible to prevent the occurrence of shocks and vibrations caused by sudden stoppage of the actuator 2 .

As described above, the shockless valve 20 can prevent the response delay of the actuator 2 when the spool 31 moves from the neutral position to the first operating position, and the spool 31 can move from the first operating position to the neutral position. It is possible to prevent the actuator 2 from generating a shock or vibration when moving to.

JP-A-08-312801

However, when the shockless valve 20 is provided separately from the spool valve 3 and the remote control valve 4 as shown in FIG. 8, the hydraulic circuit 1 becomes large and complicated. Further, with a simpler structure, the response delay of the actuator 2 when the spool 31 moves from the neutral position to one side can be prevented, and the impact of the actuator 2 when the spool returns from the one side to the neutral position can be prevented. and to prevent vibration from occurring.

Furthermore, the shockless valve 20 shown in FIG. 8 reduces the flow rate per unit time of pressure oil flowing in the direction from the pilot pressure acting portion 32a toward the remote control valve 4 even when the spool 31 moves from the neutral position to the other side. Restrict. For this reason, the spool 31 cannot immediately move from the neutral position to the other side, and the response delay of the actuator 2 occurs. Therefore, the spool is neutralized while preventing the response delay of the actuator when the spool moves from the neutral position to one side and the impact and vibration caused by the actuator when the spool returns from the one side to the neutral position. It would be desirable to have a spool valve that can prevent actuator response delays when moving from one position to the other.

The present invention has been devised in consideration of such points, and is capable of preventing a response delay of the actuator when the spool moves from the neutral position to one side and the other side with a simple structure. Further, it is an object of the present invention to provide a spool valve capable of preventing the actuator from generating impact and vibration when the spool returns to the neutral position from the one side.

A spool valve according to the present invention comprises:
a spool disposed in a spool chamber and movable by application of a pilot pressure to one end or the other end of the spool chamber;
a poppet movable to close or open one side end of the spool chamber;
The poppet is contactable with the spool.

More specifically, when the pilot pressure at one end and the other end of the spool chamber has disappeared and the spool is stopped, the poppet is in contact with the spool. .

In such a spool valve, when the pilot pressure at one end and the other end of the spool chamber disappears and the spool is stopped, the one end of the spool chamber is open. may have been

Also, the poppet includes a first internal passage communicating between a back pressure chamber containing pressurized oil for pushing the poppet toward the spool chamber and one end of the spool chamber; and a second internal passage communicating with one end of the and formed with a constriction.

Further, the poppet closes the one side end of the spool chamber when the pilot pressure at the one side end of the spool chamber disappears and the spool starts moving toward the one side end of the spool chamber. The pressure oil in the one side end of the spool chamber may flow out of the spool chamber through the second internal passage.

In this case, when the pilot pressure at the one side end of the spool chamber disappears and the spool starts to move toward the one side end of the spool chamber,
First, the poppet closes one side end of the spool chamber, and pressure oil in the one side end of the spool chamber flows out of the spool chamber through the second internal passage,
The spool may then move with the poppet to open one end of the spool chamber.

Further, in a state in which a pilot pressure is generated at one side end of the spool chamber, the poppet opens the one side end of the spool chamber,
Immediately after the pilot pressure in one end of the spool chamber is dissipated, the poppet may move closer to the spool chamber to close the one end of the spool chamber.

A valve body block formed with a spool hole for accommodating the spool, and a valve cover attached to one end of the valve body block,
The poppet may be housed within the valve cover.

According to the present invention, a response delay of an actuator when a spool moves from a neutral position to one side (the other side of the neutral position) and the other side (the one side of the neutral position) is prevented with a simple structure. In addition, it is possible to provide a spool valve that can prevent the actuator from generating impact and vibration when the spool returns from the one side (the other side of the neutral position) to the neutral position.

1 is a hydraulic circuit diagram showing an example of a hydraulic circuit using a spool valve according to an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view schematically showing one side end of the spool valve shown in FIG. 1, the spool positioned in the spool chamber and positioned at a neutral position, and the poppet positioned to open the one side end of the spool chamber; figure. FIG. 3 is a view corresponding to FIG. 2 and schematically showing a cross-sectional view of the spool starting to move from the neutral position to the first operating position and the poppet moving away from the spool; FIG. 3 is a view corresponding to FIG. 2 and schematically showing a cross-sectional view of the spool beginning to move from the first operating position to the neutral position and the poppet positioned to close one side end of the spool chamber; FIG. 3 is a view corresponding to FIG. 2 , and is a cross-sectional view schematically showing the spool that has moved from the position shown in FIG. 4 toward a neutral position, and the poppet that is pushed by the spool and moves together with the spool; FIG. 3 is a view corresponding to FIG. 2 , and is a cross-sectional view schematically showing a spool that has started to move from a neutral position to a second operating position, and a poppet that is pushed by the spool and moves together with the spool; FIG. 3 is a view corresponding to FIG. 2 , and is a cross-sectional view schematically showing the spool that has started to move from the second operating position to the neutral position and the poppet that moves following the spool; A hydraulic circuit diagram showing an example of a hydraulic circuit using a conventional shockless valve.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings attached to this specification are simplified, and the drawings include parts where, for example, the dimensions of each element, the dimensional ratio between each element, and the specific shape of each element differ from those of the real thing. can be However, those skilled in the art will be able to fully appreciate the embodiments described below and other embodiments of the invention from such simplified drawings. 1 to 7, parts similar to those of the conventional example shown in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows an example of a hydraulic circuit using a spool valve according to one embodiment of the invention. The spool valve 30 functions as a directional switching valve for controlling supply and discharge of pressure oil to and from the actuator. The spool valve 30 has a spool 31 on one side (the left side in FIG. 1; in the illustrated example, the other side in the axial direction Dx described later) and on the other side (the right side in FIG. 1; A function (response delay prevention function) for preventing a response delay of the actuator 2 when moving in the axial direction Dx in the example, and a function for preventing the spool 31 from returning to the neutral position from the one side (left side in FIG. 1). and a function (shockless function) to prevent the occurrence of shock and vibration by the actuator 2 of the above. FIG. 2 is a partial cross-sectional view schematically showing a cross section of one side (right side in FIG. 1) end (one side end in the axial direction Dx) of the spool valve 30 shown in FIG.

As shown in FIGS. 1 and 2, the spool valve 30 of this embodiment has, as main components, a valve body block 33 and a spool 31 housed in a spool hole 33a of the valve body block 33. ing. The spool hole 33a defines at least part of a spool chamber 40, which will be described later. The spool 31 is a rod-shaped member and has a longitudinal direction. The spool 31 is supported by the valve body block 33 so as to be movable in a direction Dx parallel to its central axis Ax (hereinafter also simply referred to as "axial direction").

The spool valve 30 includes a pilot pressure acting portion 50 located on one side in the axial direction Dx and a pilot pressure acting portion 32b located on the other side in the axial direction Dx. The pilot pressure acting portions 50 and 32b are means for applying pilot pressure to the ends of the spool 31 for the purpose of driving the spool 31. As shown in FIG. The spool 31 can move to one side and the other side of the neutral position in the axial direction Dx by the action of the pilot pressure at both ends of the spool chamber 40 .

The spool valve 30 shown in FIGS. 1 and 2 has an oil supply port connected to the main hydraulic pressure source 5 and an oil drain port connected to the tank 7 . The spool valve 30 changes the connection state between the oil supply port and the oil discharge port and the two ports of the actuator 2 according to the position of the spool 31 . Specifically, the position of the spool 31 is changed to the neutral position shown in FIG. 1, the first operating position moved from the neutral position to the other side in the axial direction Dx (the left side in FIG. 1), and the axial direction Dx from the neutral position. The connection state between the oil supply port and the oil discharge port of the spool valve 30 and the two ports of the actuator 2 is changed by changing between the second operating position moved to one side (right side in FIG. 1). do.

When the spool 31 is in the neutral position shown in FIG. 1, the oil supply port and the oil discharge port of the spool valve 30 are not connected to the ports of the actuator 2 . Therefore, pressure oil is not supplied to or discharged from the actuator 2 . In the illustrated example, the actuator 2 is a hydraulic cylinder having a piston rod 2r, and includes a head side port provided in the head side oil chamber 2a, a rod side port provided in the rod side oil chamber 2b, have Since the oil supply port and the oil discharge port of the spool valve 30 are not connected to either the head side port or the rod side port, pressure oil is not supplied to or discharged from the head side oil chamber 2a or the rod side oil chamber 2b. 2 piston rod 2r does not move.

On the other hand, when the spool 31 is in the first operating position, the oil supply port and the oil discharge port of the spool valve 3 are connected to one port and the other port of the actuator 2, respectively. In the illustrated example, when the spool 31 is in the first operating position, the oil supply port is connected to the head side port and the oil drain port is connected to the rod side port. As a result, the main hydraulic pressure source 5 and the head-side oil chamber 2a communicate with each other through the spool valve 30, and the rod-side oil chamber 2b and the tank 7 communicate with each other. As a result, pressure oil is supplied to the head-side oil chamber 2a and simultaneously discharged from the rod-side oil chamber 2b, so that the piston rod 2r of the hydraulic cylinder 2 begins to extend.

Further, when the spool 31 is in the second operating position, the oil supply port and the oil discharge port of the spool valve 3 are connected to the other port and one port of the actuator 2, respectively. In the illustrated example, when the spool 31 is in the second operating position, the oil supply port is connected to the rod side port and the oil drain port is connected to the head side port. As a result, the main hydraulic pressure source 5 and the rod-side oil chamber 2b communicate with each other through the spool valve 30, and the head-side oil chamber 2a and the tank 7 communicate with each other. As a result, the pressure oil is supplied to the rod-side oil chamber 2b and at the same time, the pressure oil is discharged from the head-side oil chamber 2a, so that the piston rod 2r of the hydraulic cylinder 2 is retracted.

The spool valve 30 shown in FIGS. 1 and 2 has a function (first response delay prevention function) for preventing a response delay when the actuator 2 is operated by moving the spool 31 from the neutral position to the first operating position; A function (shockless function) is provided to prevent the occurrence of shock and vibration when the spool 31 is moved from the first operating position to the neutral position to stop the operation of the actuator 2 . Further, the spool valve 30 is provided with a function (second response delay prevention function) for preventing response delay when the actuator 2 is operated by moving the spool 31 from the neutral position to the second operating position. The configuration of the spool valve 30 of this embodiment will be described in detail below with reference to FIG.

As shown in FIG. 2, the spool valve 30 has a valve cover 51 attached to one end of the valve body block 33 in the axial direction Dx, and a poppet 61 housed in the valve cover 51. there is In the illustrated example, the pilot pressure acting portion 50 is composed of a valve cover 51 and a poppet 61 .

The valve cover 51 is a cylindrical member closed at one end in the axial direction Dx. Inside the valve cover 51 , an annular protruding portion 53 is provided that extends from the inner peripheral wall of the valve cover 51 toward the center axis Ax of the spool 31 . The circumferential projection 53 defines an opening 53a that communicates between the space on one side of the circumferential projection 53 and the space on the other side.

Of the internal space of the valve cover 51, the space on the other side of the circumferential protrusion 53 in the axial direction Dx communicates with the internal space of the spool hole 33a that accommodates the spool 31, and the one side of the spool 31 in the axial direction Dx. contains the ends. Therefore, it can be considered that the spool hole 51a is formed on the other side of the circumferential protrusion 53 of the valve cover 51 . The spool hole 51a forms a spool chamber 40 that accommodates the spool 31 together with the spool hole 33a. The spool chamber 40 extends along the center axis Ax of the spool 31 . One end of the spool chamber 40 in the axial direction Dx is defined by a circumferential protrusion 53 . The spool chamber 40 accommodates the spool 31 so as to be movable in the axial direction Dx, and is supplied with pressure oil for moving the spool 31 in the axial direction Dx as described later.

That is, the valve cover 51 and the valve body block 33 constitute a valve body 35 that movably accommodates the spool 31 . However, the present invention is not limited to this example, and the valve cover 51 and the valve body block 33 may be integrally formed. Also, the spool chamber 40 may be formed only by the spool hole 33 a of the valve body block 33 .

Of the internal space of the valve cover 51 , a space on one side of the circumferential protrusion 53 in the axial direction Dx forms an operating oil passage 52 that communicates with the pilot line 11 . The hydraulic oil passage 52 has a portion 52a extending in a direction non-parallel to the axial direction Dx, particularly in a direction perpendicular to it, and communicates with the pilot line 11 at the portion 52a. When the pilot hydraulic pressure source 6 and the pilot line 11 are communicated by the remote control valve 4 and pressurized oil is supplied to the pilot line 11 , the pressurized oil is supplied to the hydraulic oil passage 52 , and the pilot oil is supplied to the hydraulic oil passage 52 . pressure is generated.

A poppet 61 is movably accommodated in the valve body 35 . In the illustrated example, the poppet 61 is positioned within the valve cover 51 as described above. The poppet 61 is movable in the axial direction Dx between a position where one side end of the spool chamber 40 is closed and a position where the one side end of the spool chamber 40 is opened to communicate with the hydraulic oil passage 52. are placed in The poppet 61 forms a poppet valve 60 that is seated on the circumferential protrusion 53 and closes one end of the spool chamber 40 . By using the poppet 61, it is possible to realize the spool valve 30 having the above-described first response delay prevention function and shockless function with a simple configuration. Further, by disposing the poppet 61 inside the valve cover 51, the spool valve 30 having the first response delay prevention function and the shockless function can be easily assembled.

In order to allow the poppet 61 to move in the axial direction Dx, a back pressure chamber 66 is formed on one side of the poppet 61 within the valve cover 51 . The back pressure chamber 66 contains pressure oil that pushes the poppet 61 toward the spool chamber 40 . More specifically, a concave portion 67 extending in the axial direction Dx is formed on one side of the working flow path 52 in the valve cover 51 . The recess 67 opens into the hydraulic oil passage 52 and accommodates one end of the poppet 61 in the axial direction Dx. A back pressure chamber 66 is defined by the recess 67 and the poppet 61 . The shape and dimensions of the recess 67 correspond to the shape and dimensions of one side end of the poppet 61, and the pressurized oil in the back pressure chamber 66 operates by passing between the poppet 61 and the inner peripheral surface of the recess 67. It is designed not to flow out into the flow path 52 . In the illustrated example, the back pressure chamber 66 accommodates a spring 68 that biases the poppet 61 toward the spool chamber 40 .

The poppet 61 has a body portion 62 arranged on one side of the circumferential protrusion 53 (that is, on the hydraulic oil passage 52 side). One end of the body portion 62 in the axial direction Dx is accommodated in the recess 67 . The other side end portion of the body portion 62 is located in the hydraulic oil passage 52 and faces the opening 53 a defined by the circumferential projection portion 53 .

A shoulder portion 64 is formed at the other end portion of the body portion 62 (that is, the end portion on the side facing the circumferential protrusion 53). The shoulder portion 64 circumferentially contacts the circumferential protrusion 53 when the poppet 61 is seated on the circumferential protrusion 53 . In this specification, the state in which the shoulder portion 64 is in circumferential contact with the circumferential protrusion 53 is referred to as a state in which one side end of the spool chamber 40 is closed. Further, the shoulder portion 64 is separated from the circumferential projecting portion 53, and the one side end portion of the spool chamber 40 and the hydraulic oil passage 52 are communicated through the gap between the poppet 61 and the inner peripheral surface of the opening 53a. The state in which one side end of the spool chamber 40 is open is called a state in which the spool chamber 40 is open. The shoulder 64 has an inclined surface 65 inclined with respect to one direction. In the illustrated example, the inclined surface 65 has a shape of a side surface of a cone or a side surface of a truncated cone that tapers toward the spool 31 side along the axial direction Dx.

In the illustrated example, the poppet 61 further has an extending portion 63 extending from the other side end portion of the main body portion 62 to the other side in the axial direction Dx. The extension 63 extends into one side end of the spool chamber 40 through the opening 53a. The other end of the extension 63 faces one end of the spool 31 .

A surface 62a of the body portion 62 facing the back pressure chamber 66 forms a first action surface on which the pressure of the pressure oil in the back pressure chamber 66 and the elastic force of the spring 68 act. A surface 63a of the extending portion 63 on the spool 31 side forms a second working surface on which the pressure of the pressure oil in the one side end of the spool chamber 40 or the pressing force of the spool 31 acts. Further, the shoulder portion 64 is also pressured by the pressure oil in the hydraulic oil passage 52 .

When the spool 31 is in the neutral position shown in FIG. 1, the poppet 61 is such that the tip of the extending portion 63 (the end on the side of the second working surface 63a) comes into contact with one side end of the spool 31. ing. Further, in the illustrated example, when the spool 31 is in the neutral position shown in FIG. 1, the main body portion 62 of the poppet 61 is separated from the circumferential projecting portion 53 and one end of the spool chamber 40 is open. It communicates with the hydraulic oil passage 52 . Specifically, by adjusting the elastic force of the spring 68 and the elastic force of the spring 13, such a design can be made possible.

The poppet 61 is also provided with a first internal passage 71 that communicates the back pressure chamber 66 with one end of the spool chamber 40 . One end of the spool chamber 40 and the back pressure chamber 66 are maintained at the same pressure through the first internal passage 71 . However, in the poppet 61, the area of the first action surface 62a of the body portion 62 on the back pressure chamber 66 side is larger than the area of the second action surface 63a of the extension portion 63 on the spool chamber 40 side. The poppet 61 is pushed toward the spool 31 when there is no pressure oil acting on the poppet 61 . The poppet 61 is also provided with a second internal passage 72 that communicates the hydraulic oil passage 52 with one end of the spool chamber 40 . A throttle 73 is formed in the second internal passage 72 . Due to this throttle 73 , the flow rate of pressure oil that can flow through the second internal passage 72 per unit time is kept sufficiently low compared to the first internal passage 71 .

The operation of the spool valve will now be described with reference to FIGS.

First, when the operating lever 4a of the remote control valve 4 is not operated, both the pilot lines 11 and 12 are communicated with the tank 7. As shown in FIG. Therefore, pressure oil is not supplied from the pilot hydraulic pressure source 6 to the pilot lines 11 and 12, and no pilot pressure is generated in any of the pilot pressure acting portions 50 and 32b. Therefore, no pilot pressure acts on the spool 31, and the spool 31 is held at the neutral position shown in FIGS. When the spool 31 is in the neutral position, as shown in FIG. 2, one side end of the spool 31 and the other side end of the poppet 61 are in contact, and one side end of the spool chamber 40 is open. and communicates with the hydraulic oil passage 52 .

Next, referring to FIG. 3, the operation of spool valve 30 when moving spool 31 from the neutral position to the first operating position will be described. When moving the spool 31 from the neutral position to the first operating position, the control lever 4a of the remote control valve 4 is operated to communicate the pilot hydraulic pressure source 6 and the pilot line 11, and pressure is applied from the pilot hydraulic pressure source 6 to the pilot line 11. supply oil. The pressure oil supplied to the pilot line 11 flows into the working oil passage 52 . As a result, a pilot pressure corresponding to the amount of operation of the operating lever 4a is generated in the operating oil passage 52. As shown in FIG. As shown in FIG. 3, one end of the spool chamber 40 is opened and communicated with the hydraulic fluid passage 52 before the pilot pressure is generated in the hydraulic fluid passage 52. Therefore, when the pressure in the hydraulic fluid passage 52 increases, , the pressure oil in the hydraulic oil passage 52 immediately flows into one end of the spool chamber 40 . As a result, the pilot pressure of the hydraulic fluid passage 52 immediately acts on one side end of the spool 31, and the spool 31 moves away from the poppet 61 in the direction S1 (that is, the axis to the other side of direction Dx) immediately. As a result, the actuator 2 immediately operates according to the operation of the operating lever 4a without delay in response. Therefore, the operator of the operating lever 4a can cause the actuator 2 to perform a desired operation, and can operate the actuator 2 without discomfort.

Here, the poppet 61 resists the back pressure that the pilot pressure acting on the shoulder portion 64 applies to the first action surface 62a from the back pressure chamber 66, and moves away from the spool 31 in the direction P2 (that is, one side in the axial direction Dx). ). Therefore, the hydraulic oil passage 52 and one end of the spool chamber 40 are maintained in communication. As a result, the pilot pressure continues to act on the one end of the spool 31 while the pilot pressure is being generated in the hydraulic fluid passage 52 . As a result, rapid movement of the spool 31 to the first operating position is achieved.

Note that even if one end of the spool chamber 40 is closed by the poppet 61 before the pilot pressure is generated in the hydraulic oil passage 52, the actuator 2 will not operate when the spool 31 moves to the first operating position. Response delay can be prevented. This is because even if the poppet 61 is seated on the circumferential projecting portion 53 and one side end of the spool chamber 40 is closed, the pilot pressure generated in the hydraulic oil passage 52 acts on the shoulder portion 64 of the poppet 61 . , the poppet 61 can be immediately moved in the direction P2 (that is, one side of the axial direction Dx) in which the shoulder portion 64 is separated from the circumferential projection 53, and the one side end portion of the spool chamber 40 can be opened. is.

The operation of the spool valve 30 when moving the spool 31 from the first operating position to the neutral position will now be described with reference to FIGS. 4 and 5. FIG. When moving the spool 31 from the first operating position to the neutral position, the control lever 4 a of the remote control valve 4 is operated to connect the pilot line 11 to the tank 7 . As a result, immediately after the pilot pressure in the working oil passage 52 disappears, the poppet 61 moves toward the circumferential projecting portion 53 in the direction P1 of the shoulder portion 64 due to the elastic force of the spring 68 in the back pressure chamber 66 . (that is, the other side of the axial direction Dx) (see FIG. 4). Then, the poppet 61 is seated on the circumferential protrusion 53 to close one end of the spool chamber 40 . At this time, the pressure in the hydraulic fluid passage 52 is lower than the pressure at one end of the spool chamber 40 . Therefore, the pressure oil at one end of the spool chamber 40 flows through the second internal flow path 72 into the working oil path 52 , but the flow rate per unit time is limited by the throttle 73 . Therefore, the pressure of the pressurized oil applied to one end of the spool 31 does not drop immediately after the operating lever 4a is operated.

As the pressure oil at the one end of the spool chamber 40 flows into the working oil passage 52 via the second internal flow path 72, the pressure at the one end of the spool chamber 40 gradually decreases, and the spool 31 slowly moves in the direction S2 toward the poppet 61 . As shown in FIG. 5, when the spool 31 abuts against the poppet 61, the spool 31 moves the poppet 61 in a direction P2 (that is, one side in the axial direction Dx) in which the shoulder portion 64 of the poppet 61 separates from the circumferential protrusion 53. push. As a result, the one side end of the spool chamber 40 is opened to communicate with the working oil passage 52 , and the pressurized oil in the one side end of the spool chamber 40 immediately flows into the working oil passage 52 . As a result, the pressure at one end of the spool chamber 40 quickly drops. After the one side end of the spool chamber 40 is opened, the spool 31 quickly moves to the intermediate position.

In this way, the poppet 61, which is positioned to open one side end of the spool chamber 40 in a state where the pilot pressure is generated in the working oil passage 52, immediately after the pilot pressure in the working oil passage 52 disappears. One end of the spool chamber 40 is closed by being pushed to the other side in the axial direction Dx, and the flow rate of pressure oil from the one end of the spool chamber 40 to the hydraulic oil passage 52 per unit time is restricted. As a result, the spool 31 is moved from the first operating position to the neutral position and the actuator 2 is operated while preventing a delay in response when the spool 31 is moved from the neutral position to the first operating position and the actuator 2 is operated. It is possible to prevent the occurrence of shock and vibration when stopping.

In particular, in the illustrated example, the poppet 61 is provided with a first internal passage 71 that communicates between one side end of the spool chamber 40 and the back pressure chamber 66 , so that the pressure in the back pressure chamber 66 is can be equal to the pressure in one end of the As a result, the movement of the poppet 61 is not hindered due to excessively high or low pressure in the back pressure chamber 66 .

Further, by providing the second internal passage 72 with the restrictor 73 in the poppet 61, the flow rate per unit time of the pressurized oil flowing from one end of the spool chamber 40 to the hydraulic oil passage 52 can be stably restricted. can be done. As a result, the movement of the spool 31 from the first operating position to the neutral position can be stably slowed down. As a result, it is possible to stably prevent the occurrence of shocks and vibrations due to the spool 31 moving toward the neutral position at high speed and the actuator 2 suddenly stopping.

On the other hand, spool 31 contacts poppet 61 before reaching the neutral position. The spool 31 pushes the poppet 61 and moves together with the poppet 61 to open one end of the spool chamber 40 to communicate with the hydraulic oil passage 52 . As a result, the operation of the spool 31 can be slowed down for a while after the pilot pressure in the hydraulic fluid passage 52 has disappeared, and then the spool 31 can be moved quickly. As a result, it is possible to effectively prevent the occurrence of an excessive response delay in the operation of the actuator 2 due to the exertion of the shockless function.

Next, referring to FIG. 6, the operation of the spool valve 30 when moving the spool 31 from the neutral position to the second operating position will be described. When moving the spool 31 from the neutral position to the second operating position, the control lever 4 a of the remote control valve 4 is operated to connect the pilot line 12 to the pilot hydraulic pressure source 6 . As a result, pressure oil is supplied from the pilot hydraulic pressure source 6 to the pilot pressure acting portion 32b. As a result, a pilot pressure corresponding to the amount of operation of the operating lever 4 a is generated in the pilot pressure acting portion 32 b , and the pilot pressure acts on the other side end portion of the spool 31 . Then, the spool 31 starts to move in the direction S2 toward the second operating position (that is, one side of the axial direction Dx). At this time, one side end of the spool 31 and the other side end of the poppet 61 are in contact with each other. It is moved in the separating direction P2 (that is, one side of the axial direction Dx). Therefore, one side end of the spool chamber 40 is kept open. Therefore, when the spool 31 moves from the neutral position to the second operating position, the flow rate per unit time of the pressure oil flowing from the one side end of the spool chamber 40 to the hydraulic oil passage 52 is restricted, thereby hindering the movement of the spool 31. There is no such thing as

In this way, by maintaining the one side end of the spool chamber 40 in an open state, when the pilot pressure is generated in the pilot pressure acting portion 32b, the spool 31 immediately moves to one side in the axial direction Dx. can move. As a result, the actuator 2 immediately operates in response to the operation of the operating lever 4a without delay in response. Therefore, the operator of the operating lever 4a can cause the actuator 2 to perform a desired operation, and can operate the actuator 2 without discomfort.

Next, referring to FIG. 7, the operation of the spool valve 30 when moving the spool 31 from the second operating position to the neutral position will be described. When moving the spool 31 from the second operating position to the neutral position, the operation lever 4 a of the remote control valve 4 is operated to connect the pilot line 12 to the tank 7 . When the pilot pressure of the pilot pressure acting portion 32b disappears, the spool 31 starts to move in the direction S1 toward the neutral position due to the elastic force of the spring 13. As shown in FIG. At this time, as shown in FIG. 7, the poppet 61 moves in a direction P2 (that is, the other side of the axial direction Dx) following the spool 31 due to the elastic force of the spring 68 received by the first action surface 62a. return to the position shown in .

Although the case where the pilot pressure acting portion 50 located on one side of the spool 31 is configured by the valve cover 51 and the poppet 61 has been described above, the present invention is not limited to this. For example, the pilot pressure acting portion 32b located on the other side of the spool valve 30 may be composed of the same valve cover and poppet as the pilot pressure acting portion 50 does. In this case, the valve cover accommodates the other end of the spool 31 in the axial direction Dx, and the hydraulic oil passage provided in the valve cover communicates with the pilot line 12 . The spool valve 30 configured in this way has a function of preventing a response delay of the actuator 2 when the actuator is operated by moving the spool 31 from the neutral position to the second operating position and the first operating position (response delay prevention function). function) and a function (shockless function) of preventing the occurrence of shock and vibration when the spool 31 is moved from the second operating position to the neutral position to stop the operation of the actuator 2 .

A pilot pressure acting portion 50 positioned on one side of the spool 31 is constituted by the valve cover 51 and the poppet 61, and a pilot pressure acting portion 32b positioned on the other side of the spool 31 in the axial direction Dx is provided with a pilot pressure. It may be configured by a valve cover and a poppet similar to the acting portion 50 . That is, pilot pressure acting portions 50 or pilot pressure acting portions configured similarly to the pilot pressure acting portions 50 may be provided on both sides of the spool 31 .

When the pilot pressure acting portion 50 or the pilot pressure acting portion configured similarly to the pilot pressure acting portion 50 is provided on both sides of the spool 31, the spool valve operates as follows. That is, when the spool 31 moves from the neutral position to the first operating position, the spool 31 pushes the poppet of the pilot pressure acting portion 32b to move the other side end of the spool chamber 40 (the end on the pilot pressure acting portion 32b side). open the Therefore, the pressure oil at the other end of the spool chamber 40 immediately flows into the working oil path of the pilot pressure acting portion 32b, and the pressure of the pressure oil applied to the other end of the spool 31 is immediately reduced. This results in immediate movement of spool 31 to the first operating position. Further, when the spool 31 moves from the neutral position to the second operating position, as described above, the spool 31 pushes the poppet 61 of the pilot pressure acting portion 50 to push the one side end of the spool chamber 40 (the pilot pressure acting portion). 50 side) is opened. Therefore, the pressure oil at one end of the spool chamber 40 immediately flows into the working oil passage 52, and the pressure of the pressure oil applied to the one end of the spool 31 is immediately reduced. This results in immediate movement of spool 31 to the second operating position. As described above, response delay of the actuator 2 can be prevented both when the spool 31 is moved from the neutral position to the first actuation position and when it is moved from the neutral position to the second actuation position. On the other hand, when the spool 31 moves from the first operating position to the neutral position, one end of the spool chamber 40 (the end on the side of the pilot pressure acting portion 50) is closed as described above. Therefore, the flow rate per unit time of pressure oil flowing from one end of the spool chamber 40 to the hydraulic oil passage 52 is restricted. As a result, the pressure of the pressurized oil applied to one end of the spool 31 does not drop immediately, and the spool 31 slowly moves from the first operating position to the neutral position. Further, when the spool 31 moves from the second operating position to the neutral position, the other side end of the spool chamber 40 (the end on the side of the pilot pressure acting portion 32b) is closed. Therefore, the flow rate per unit time of pressure oil flowing from the other end of the spool chamber 40 to the working oil passage of the pilot pressure acting portion 32b is restricted. As a result, the pressure of the pressurized oil applied to the other end of the spool 31 does not drop immediately, and the spool 31 slowly moves from the second operating position to the neutral position. As described above, both when the spool 31 is moved from the first operating position to the neutral position and when it is moved from the second operating position to the neutral position, the occurrence of impact and vibration when stopping the operation of the actuator 2 is suppressed. can be prevented.

Furthermore, a first internal passage 71 communicating between the back pressure chamber 66 and one end of the spool chamber 40, and a second internal passage 72 communicating between the hydraulic oil passage 52 and one end of the spool chamber 40 are , may not be provided inside the poppet 61 . For example, internal passages 71 and 72 may be formed in valve cover 51 . For example, the second internal passage 72 that communicates between the hydraulic oil passage 52 and one end of the spool chamber 40 may be formed in the circumferential protrusion 53 . Alternatively, the second internal passage 72 may be formed as a groove in the side of the poppet 61 .

The spool valve 30 according to the present embodiment described above includes the spool 31 arranged in the spool chamber 40 and movable by the application of pilot pressure to one side end and the other side end of the spool chamber 40; and a poppet 61 movable to close or open one end of the spool chamber 40 . The poppet 61 can then come into contact with the spool 31 . More specifically, when the pilot pressure at one end and the other end of the spool chamber 40 disappears and the spool 31 is stopped, that is, when the spool 31 is in the neutral position, the poppet 61 is in contact with the spool 31 .

According to the spool valve 30 as described above, when the remote control valve 4 is operated and the pilot pressure is generated in the hydraulic oil passage 52, the poppet 61 is arranged at the position where one end portion of the spool chamber 40 is opened. By not restricting the flow rate per unit time of the pressurized oil that flows from the hydraulic oil passage 52 to one side end of the spool chamber 40, the spool 31 is moved from the neutral position to the other side of the neutral position (first operating position). d) can be moved immediately. Thereby, the spool valve 30 exhibits a function (first response delay prevention function) of preventing a response delay of the actuator 2 when the spool 31 is moved from the neutral position to the other side (to the first actuation position). be able to.

Further, when the remote control valve 4 is operated and the pilot pressure in the hydraulic oil passage 52 disappears, the poppet 61 is arranged in a position to close the one side end of the spool chamber 40, and the one side end of the spool chamber 40 is closed. The spool 31 can be slowly moved from the other side (from the first operating position) to the neutral position by limiting the flow rate per unit time of the pressure oil flowing into the hydraulic oil passage 52 from the second side. As a result, the spool valve 30 exhibits a function (shockless function) of preventing the actuator 2 from generating shock and vibration when the spool 31 is moved from the other side (from the first operating position) to the neutral position. can be done.

Furthermore, when pilot pressure is generated in the pilot pressure acting portion 32b on the other side, the spool 31 is pushed from the neutral position toward one side of the neutral position (toward the second actuation position). Since the spool 31 is in contact with the poppet 61 at the neutral position, the spool 31 pushes the poppet 61 and moves together with the poppet 61 . For this reason, when the spool 31 starts to move from the neutral position to the one side (to the second operating position), even if the one side end of the spool chamber 40 is closed by the poppet 61, one side of the spool chamber 40 is closed. The side ends can be immediately opened and communicated with hydraulic fluid passage 52 . Therefore, the flow rate per unit time of the pressure oil flowing into the hydraulic oil passage 52 from the one side end of the spool chamber 40 is not limited, and the spool 31 is directed to the one side (toward the second operating position). You can start moving immediately. The poppet 61 continues to be pushed by the spool 31 until the spool 31 finishes moving to the one side (to the second operating position), and the one side end of the spool chamber 40 and the hydraulic oil passage 52 are communicated. maintained as is. Therefore, until the spool 31 finishes moving to the one side (to the second operating position), the flow rate per unit time of pressure oil flowing into the hydraulic oil passage 52 from the one side end of the spool chamber 40 is Not restricted. As a result, the spool 31 can immediately move to the one side (to the second operating position). Thus, the spool valve 30 exhibits a function (second response delay prevention function) of preventing a response delay of the actuator 2 when the spool 31 is moved from the neutral position to the one side (to the second operating position). can do.

That is, according to the spool valve 30 of the embodiment described above, the spool 31 is directed from the neutral position to the other side (to the first operating position) by the poppet 61 built into the one side end of the spool valve 30. (towards) as well as to said one side (towards a second operating position), and from said other side of spool 31 (towards a first operating position) to a neutral position. movement can be delayed. As a result, the spool valve 30 can prevent a delay in response at the start of operation of the actuator 2 when the spool 31 moves from the neutral position to the other side and the one side, and the spool 31 can be moved to the other side. It is possible to prevent the occurrence of impact when the actuator 2 stops operating when moving from the side to the neutral position.

In addition, since the poppet 61 is arranged inside the spool valve 30, the spool valve 30 itself is endowed with excellent response delay prevention function and shockless function. Therefore, there is no need to install a separate shockless valve or the like in the hydraulic circuit 10, and the increase in size and complexity of the hydraulic circuit 10 can be effectively avoided.

Further, in the present embodiment, when the pilot pressure at one end and the other end of the spool chamber 40 disappears and the spool 31 is stopped, that is, when the spool 31 is at the neutral position , one side end of the spool chamber 40 is open. Therefore, in this case, one side end of the spool chamber 40 communicates with the hydraulic oil passage 52 . As a result, when the pilot pressure is generated in the working oil passage 52, the pressurized oil in the working oil passage 52 can effectively and rapidly flow into the one end portion of the spool chamber 40. FIG. Then, the movement of the spool 31 from the neutral position to the other side can be effectively speeded up.

Further, in this configuration, when the pilot pressure in the hydraulic fluid passage 52 disappears and the spool 31 returns to the neutral position from the other side, the spool 31 is pushed out of the spool chamber 40 before reaching the neutral position. It will hit a poppet 61 closing one end. Then, the spool 31 moves to the neutral position while pushing the poppet 61 to open one side end of the spool chamber 40 . Therefore, the spool 31, which had been slowly moving toward the neutral position after the pilot pressure in the hydraulic fluid passage 52 was lost, moves toward the one side end of the spool chamber 40 after the one side end of the spool chamber 40 is opened. As the pressurized oil in the section quickly flows into the working oil passage 52, it quickly moves to the neutral position. That is, by configuring as described above, the operation of the spool 31 can be slowed for a while after the pilot pressure in the hydraulic fluid passage 52 has disappeared, and then the spool 31 can be rapidly moved. As a result, the movement of the actuator 2 when the spool 31 returns to the neutral position from the other side is delayed more than necessary as the shockless function is exhibited when the spool 31 moves from the other side to the neutral position. can be effectively prevented.

In addition, the poppet 61 includes a first internal passage 71 that communicates a back pressure chamber 66 containing pressurized oil that pushes the poppet 61 toward the spool chamber 40 and one side end of the spool chamber 40, and the outside of the spool chamber 40 ( Specifically, it has a second internal passage 72 that communicates between the hydraulic oil passage 52) and one side end of the spool chamber 40 and that has a throttle 73 formed therein. The poppet 61 is provided with the first internal passage 71 that communicates the one side end of the spool chamber 40 and the back pressure chamber 66 , so that the pressure in the back pressure chamber 66 is reduced to the one side end of the spool chamber 40 . can be equal to pressure. As a result, the movement of the poppet 61 is not hindered due to excessively high or low pressure in the back pressure chamber 66 . Further, by providing the second internal passage 72 with the restrictor 73 in the poppet 61, the flow rate per unit time of the pressurized oil flowing from one end of the spool chamber 40 to the hydraulic oil passage 52 can be stably restricted. can be done. As a result, the movement of the spool 31 from the other side (from the first operating position) to the neutral position can be stably slowed down. As a result, the spool valve 30 can stably perform the function (shockless function) of preventing the occurrence of shocks and vibrations caused by the spool 31 moving to the neutral position at high speed and the actuator 2 suddenly stopping. .

Specifically, when the pilot pressure at one end of the spool chamber 40 (and thus within the hydraulic fluid passage 52) disappears and the spool 31 begins to move toward the one end of the spool chamber 40, the poppet 61 closes one side end of the spool chamber 40, and the pressurized oil in the one side end of the spool chamber 40 flows out of the spool chamber 40 (specifically, into the hydraulic oil passage 52) through the second internal passage 72. flow to As a result, after the pilot pressure in the hydraulic oil passage 52 disappears, the pressure of the pressurized oil in the one-side end of the spool chamber 40 can be stably and gradually reduced, and the spool 31 can be moved from the other side ( It can be moved steadily and slowly towards the neutral position (from the first operating position). As a result, the operation of the actuator 2 at this time can also be stabilized.

In particular, in the present embodiment, the pilot pressure (within hydraulic fluid passage 52 ) at one end of spool chamber 40 disappears and spool 31 starts moving toward one end of spool chamber 40 . First, the poppet 61 closes one side end of the spool chamber 40, and the pressure oil in the one side end of the spool chamber 40 flows through the second internal passage 72 to the outside of the spool chamber 40 (specifically, the operating pressure). 52 ), and then the spool 31 moves with the poppet 61 to open one end of the spool chamber 40 , thereby communicating with the hydraulic fluid passage 52 . As described above, in this case, after the pilot pressure disappears, it is possible to slow the movement of the spool 31 from the other side toward the neutral position for a while, and then quickly move the spool 31 to the neutral position. can. As a result, it is possible to effectively prevent the movement of the spool 31 from the other side to the neutral position from being unnecessarily delayed due to the exertion of the shockless function when the spool 31 is moved from the other side to the neutral position. can do.

Further, in the present embodiment, in a state where pilot pressure is generated at the one side end of the spool chamber 40 (specifically, in the working oil passage 52), the poppet 61 is positioned at the one side end of the spool chamber 40. is opened, thereby communicating with the hydraulic oil passage 52 . Then, immediately after the pilot pressure at one end of the spool chamber 40 (specifically, in the hydraulic oil passage 52) disappears, the poppet 61 moves closer to the spool chamber 40, Close one end. As a result, the spool valve 30 exerts a response delay prevention function (first response delay prevention function) when the spool 31 is moved from the neutral position to the other side, and A shockless function can be exhibited when moving from the side to the neutral position.

Further, in this embodiment, the valve body block 33 formed with the spool hole 51a for accommodating the spool 31, and the valve cover 51 attached to one end of the valve body block 33 are provided. , are accommodated in the valve cover 51 . In this case, the spool valve 30 has a simple structure that can be easily assembled, and has a response delay prevention function when the spool 31 moves from the neutral position to the other side and from the neutral position to the one side. Also, a shockless function is exhibited when the spool 31 is moved from the other side to the neutral position.

The invention is not limited to the embodiments described above. For example, various modifications may be made to each element of the above-described embodiments. Embodiments of the present invention also include forms including components and/or methods other than the components and/or methods described above. Embodiments of the present invention also include forms that do not include some of the components and/or methods described above. Further, the effects achieved by the present invention are not limited to those described above, and specific effects according to the specific configurations of the respective embodiments can also be exhibited.

1, 10 Hydraulic circuit 2 Hydraulic actuator 4 Remote control valve 13 Springs 3, 30 Spool valve 31 Spool 40 Spool chamber 51 Valve cover 52 Hydraulic oil passage 53 Opening 60 Poppet valve 61 Poppet 66 Back pressure chamber 71 First internal passage 72 Second interior Passage 73 Aperture

Claims (8)

A spool having a central axis and disposed in a spool chamber extending in an axial direction parallel to the central axis, wherein a pilot pressure generated at one end or the other end of the spool chamber in the axial direction is applied to the spool. a spool movable in the axial direction by acting on one end or the other end in the axial direction ;
a poppet movable to close or open one side end of the spool chamber;
A spool valve, wherein the poppet is contactable with the spool. 2. The poppet of claim 1, wherein the poppet is in contact with the spool when pilot pressure at one end and the other end of the spool chamber is absent and the spool is stopped. spool valve. 2. The one end of the spool chamber is open when pilot pressure is lost in one end and the other end of the spool chamber and the spool is stopped. 3. or the spool valve according to 2. The poppet includes a first internal passage that communicates between a back pressure chamber that stores pressure oil that pushes the poppet toward the spool chamber and one side end of the spool chamber, and a first internal passage that communicates between the outside of the spool chamber and the one side of the spool chamber. 4. The spool valve according to any one of claims 1 to 3, further comprising a second internal passage communicating with the side end and formed with a throttle. when the pilot pressure at one end of the spool chamber disappears and the spool starts moving toward the one end of the spool chamber, the poppet closes the one end of the spool chamber; 5. The spool valve according to claim 4, wherein pressure oil in one side end of said spool chamber flows out of said spool chamber via said second internal passage. When the pilot pressure at one end of the spool chamber disappears and the spool starts moving toward the one end of the spool chamber,
First, the poppet closes one side end of the spool chamber, and pressure oil in the one side end of the spool chamber flows out of the spool chamber through the second internal passage,
6. The spool valve of claim 5, wherein said spool then moves with said poppet to open one end of said spool chamber. The poppet opens the one side end of the spool chamber in a state where a pilot pressure is generated at the one side end of the spool chamber,
The poppet moves closer to the spool chamber to close the one side end of the spool chamber immediately after the pilot pressure in the one side end of the spool chamber disappears. A spool valve according to any one of the preceding claims. a valve body block formed with a spool hole for accommodating the spool; and a valve cover attached to one end of the valve body block in the axial direction ,
A spool valve as claimed in any preceding claim, wherein the poppet is housed within the valve cover.

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