JP2020060287A - Direction selector valve - Google Patents

Abstract

To provide a direction selector valve capable of reducing the leakage of working fluid in the direction selector valve and maintaining the controllability of an actuator, in a simple construction without increasing the size of the direction selector valve.SOLUTION: A direction selector valve 3 includes a valve body 40 in which two ports are provided, and a spool 30 to be moved relative to the valve body 40 for opening/closing a flow path provided in the valve body 40 for connecting the two ports, the spool 30 having an internal passage 70 which is opened/closed with the movement relative to the valve body 40 so as to be communicated with the two ports.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a directional control valve.

  2. Description of the Related Art Direction switching valves that control supply and discharge of working fluid to and from actuators of construction machines such as hydraulic excavators have been known. The direction switching valve has a valve body and a spool housed in a spool hole formed in the valve body.

  The valve body is provided with a supply port communicating with the main pump and a tank port communicating with the tank. Further, the actuator has a fluid chamber that accommodates a working fluid, and the valve body is provided with an actuator port that communicates with this fluid chamber. Further, the valve body is provided with a passage communicating with each port. These passages open to the spool holes and are connected through the spool holes to form a working fluid flow path together with the spool holes. That is, the ports are connected by the flow path. A portion of the inner wall of the spool hole between the openings where the flow path is opened forms an annular land portion.

  The spool has a plurality of land portions that can be fitted to the annular land portion and a cutout portion arranged between the land portions. By moving the spool in the spool hole and changing the positions of the land portion and the notch portion with respect to the annular land portion, it is possible to open and close the flow path connecting the ports, and to supply and discharge the working fluid to and from the actuator. It can be controlled.

  For example, the land portion of the spool is an annular land portion between the opening portion of the actuator passage communicating with the actuator port and the opening portion of the tank passage communicating with the tank port (hereinafter, referred to as “tank-side annular land portion”). It is possible to close the flow path connecting the actuator port and the tank port by closing the inner space of the annular land portion by fitting with. This can prevent discharge of the working fluid from the actuator. On the other hand, by separating the land portion from the tank-side annular land portion and disposing the cutout portion in the internal space of the tank-side annular land portion, the internal space can be opened. Thereby, the flow path connecting the actuator port and the tank port can be opened, and the working fluid can be discharged from the actuator.

  As described above, by opening and closing the flow path connecting the actuator port and the tank port, and the flow path connecting the actuator port and the supply port, it is possible to control the supply and discharge of the working fluid to and from the actuator. , The actuator can be operated as desired. When the spool is in the so-called "neutral position", the land portion of the spool closes the flow path between the actuator port and the tank port and the flow path between the actuator port and the supply port to operate the actuator. Fluid supply / discharge is stopped. As a result, the actuator does not move and its posture is maintained.

  In such a directional control valve, for example, if the working fluid is discharged from the actuator only after the land portion is separated from the tank-side annular land portion, the actuator suddenly operates and shock and vibration are generated. Will end up. In order to prevent such a situation, a method is known in which a notch is provided on the outer peripheral surface of the land portion of the spool to cause a so-called "pre-flow" of the working fluid to prevent the actuator from generating impact and vibration. There is. For example, in order to prevent the impact and vibration from being generated by the actuator when the land part separates from the tank-side annular land part, on the outer peripheral surface of the land part, from the actuator passage side end of the land part to the tank passage side, Provide a notch that extends to the middle of the land. Then, before the spool moves from the neutral position to the tank passage side and the land portion separates from the tank-side annular land portion, the actuator passage and the tank passage are communicated with each other through the notch, and the working fluid is discharged little by little from the actuator. As a result, the operation of the actuator can be started before the land part separates from the tank-side annular land part, and it is possible to prevent the occurrence of vibration and impact due to the abrupt operation of the actuator.

JP, 2005-155278, A Japanese Patent Laid-Open No. 01-269705

  By the way, such a notch generally has a sufficient length so that the actuator can be stably operated before the land part separates from the annular land part.

  On the other hand, if the notch has the sufficient length, unintended leakage of the working fluid may occur in the directional control valve. For example, when the notch as described above is provided in the land portion that fits into the tank passage-side annular land portion, the land portion has the actuator port and the tank port only in the portion on the tank passage side of the notch. The connecting flow path can be closed. The length along the moving direction of the spool of the area where this portion and the annular land portion on the tank passage side overlap is called the overlap amount. If this overlap amount is not large enough, the working fluid leaks from one side of the tank passage side annular land portion to the other side, specifically, from the actuator passage side to the tank passage side. Therefore, the working fluid in the fluid chamber of the actuator decreases, and the posture of the actuator cannot be maintained.

  If the notch length is shortened and the overlap amount is increased in order to reduce the leakage of the working fluid, the controllability of the actuator is changed. For example, the time length from the start of the operation of the directional control valve to the start of the operation of the actuator changes. Further, the actuator cannot be sufficiently operated before the land part is separated from the annular land part. For this reason, the operator feels uncomfortable. Further, in order to prevent the leakage of the working fluid, a check poppet may be provided in the actuator port to prevent the working fluid from flowing out from the actuator as in the directional control valve described in Patent Document 2, but in this case. However, the direction switching valve becomes complicated and large.

  The present invention has been made in consideration of the above point, and is a directional switching valve capable of preventing vibration and impact from occurring due to abrupt movement of an actuator. It is an object of the present invention to provide a directional switching valve that can reduce the leakage of the working fluid in the directional switching valve with a simple configuration without performing the above and can maintain the controllability of the actuator.

The directional control valve according to the present invention comprises
A valve body provided with two ports,
A spool that is provided in the valve body and that opens and closes a flow path that connects the two ports, the spool having an internal passage that is opened and closed with movement of the valve body and that communicates with the two ports, Equipped with.

  In this case, the internal passage of the spool may be opened before the flow passage in the valve body.

  Further, the internal passage of the spool may be opened by the action of the working fluid that moves the spool.

  In this case, the internal passage of the spool may be opened before starting the movement of the spool.

Further, the spool has a cutout portion that connects the two ports, and a land portion that blocks the two ports,
The land portion is provided with an elongated notch in the moving direction of the spool,
One end of the internal passage opens on the land portion at a position that is on the front side when the spool moves from the position where the flow passage in the valve body is closed to the position where the flow passage is opened, rather than the notch. May be.

  In this case, the one end of the internal passage may open in a position that partially overlaps the notch in the moving direction of the spool.

  Further, the one end of the internal passage may open at a position deviated from the notch in a circumferential direction centered on a moving direction of the spool.

  Further, the internal passage of the spool may be opened and closed as the selector moves.

  In this case, the selector may move as the spool moves with respect to the valve body.

  Further, in this case, the selector may be moved by the action of the working fluid that moves the spool.

Alternatively, the directional control valve according to the invention is
A valve body provided with two ports,
A spool that moves with respect to the valve body to open and close a flow path that is provided in the valve body and that connects the two ports;
A selector that opens and closes an internal passage formed in the spool and communicating with the two ports by moving with respect to the spool.

  In this case, the selector may move with respect to the spool as the spool moves with respect to the valve body.

  Further, the internal passage of the spool may be opened before the flow passage in the valve body.

  Further, the selector may be moved by the action of the working fluid that moves the spool.

  In this case, the spool may be provided with a selector hole that accommodates the selector, and a working fluid hole that opens to the pressure receiving surface on which the working fluid acts and communicates with the selector hole.

  Further, the internal passage of the spool may be opened before the movement of the spool is started.

Further, the spool has a cutout portion that connects the two ports, and a land portion that blocks the two ports,
The land portion is provided with an elongated notch in the moving direction of the spool,
One end of the internal passage opens on the land portion at a position that is on the front side in the moving direction of the spool from the position that closes the flow path in the valve body to the position that opens the flow path, rather than the notch. May be.

  In this case, the one end of the internal passage may open in a position that partially overlaps the notch in the moving direction of the spool.

  Further, the one end of the internal passage may open at a position deviated from the notch in a circumferential direction centered on a moving direction of the spool.

  Further, the internal passage of the spool may be closed in a state where the spool is maintained at a position that closes the flow passage in the valve body.

  The internal passage of the spool may be opened when the spool moves from a position where the flow passage in the valve body is closed to a position where the flow passage is opened.

  Further, the internal passage of the spool may be opened in a state where the spool is maintained at a position where the flow passage is opened in the valve body.

  According to the present invention, there is provided a directional switching valve capable of preventing vibration and impact from being generated due to abrupt movement of an actuator. It is possible to provide a directional control valve capable of reducing the leakage of the working fluid and maintaining the controllability of the actuator.

FIG. 3 is a working fluid circuit diagram showing an example of a working fluid circuit using the directional control valve according to the embodiment of the present invention. Sectional drawing of the direction switching valve shown in FIG. Sectional drawing which shows typically the internal passage and the selector formed in the spool of the direction switching valve shown in FIG. The front view which shows the opening part and notch of the internal passage provided in the outer peripheral surface of the spool shown in FIG. Sectional drawing which followed the II line | wire of FIG. Sectional drawing which shows typically the internal passage and selector shown in FIG. Sectional drawing which shows typically the internal passage and selector shown in FIG. Sectional drawing which shows typically the internal passage and selector shown in FIG. Sectional drawing which shows typically the internal passage and selector shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings attached to the present specification are simplified and, for example, the drawings include portions in which the dimensions of each element, the dimensional ratio between each element, and the specific shape of each element differ from those of the actual product. Can be However, those skilled in the art can fully understand the embodiments described below and other embodiments of the present invention from such simplified drawings.

  FIG. 1 shows an example of a working fluid circuit using a directional control valve according to an embodiment of the present invention.

  The working fluid circuit 1 shown in FIG. 1 includes an actuator 2, a directional switching valve 3 for controlling supply and discharge of a working fluid (pressure oil in the illustrated example) to the actuator 2, and an actuator via the directional switching valve 3. 2 and a main pump 5 for supplying a working fluid. The working fluid circuit 1 also includes a pilot control valve (hereinafter, referred to as a remote control valve) 4 for controlling the operation of the directional control valve 3, a pilot pump 6, and a tank 7.

  In the illustrated example, the actuator 2 is a hydraulic cylinder having a piston rod 2r and has a head side fluid chamber 2a and a rod side fluid chamber 2b.

  The direction switching valve 3 is connected to the main pump 5 and the tank 7. The direction switching valve 3 has a spool 30, and by moving the spool 30 in the first direction (the left-right direction in FIG. 1) D1, the main pump 5 and the tank 7, and the head-side fluid chamber 2a of the actuator 2 are moved. The connection state between the rod side fluid chamber 2b and the rod side fluid chamber 2b can be changed.

  As shown in FIG. 1, the directional control valve 3 includes pilot pressure acting portions 51 and 52 at both ends in the first direction D1. The pilot pressure acting portions 51 and 52 are means for applying pilot pressure to the end portion of the spool 30 for the purpose of driving the spool 30. By loading the pilot pressure on the pilot pressure acting portion 51 located on the other side of the first direction D1 (left side in FIG. 1), the spool 30 is moved from the neutral position shown in FIG. It can be moved to the first operating position which has been moved to the right in FIG. 1). Further, by loading the pilot pressure on the pilot pressure acting portion 52 located on one side of the first direction D1 (on the right side of FIG. 1), the spool 30 is moved from the neutral position shown in FIG. It can be moved to the second operating position, which has moved to the side (to the left in FIG. 1).

  The direction switching valve 3 also includes elastic members 61 and 62 that apply an elastic force to the spool 30 in the first direction D1. When the pilot pressure is not generated in the pilot pressure acting portions 51 and 52 by the elastic members 61 and 62, the spool 30 is held at the neutral position shown in FIG.

  When the spool 30 is in the neutral position, the main pump 5 and the tank 7 are not connected to either the head side fluid chamber 2a or the rod side fluid chamber 2b of the actuator 2 (see FIG. 1), and the actuator 2 The working fluid is not supplied to or discharged from the unit. On the other hand, when the spool 30 is in the first operating position, the main pump 5 and the tank 7 are connected to the rod side fluid chamber 2b and the head side fluid chamber 2a of the actuator 2, respectively. As a result, the working fluid is supplied to the rod-side fluid chamber 2b, and at the same time, the working fluid is discharged from the head-side fluid chamber 2a, and the piston rod 2r moves in the pulling direction. When the spool 30 is in the second operating position, the main pump 5 and the tank 7 are connected to the head side fluid chamber 2a and the rod side fluid chamber 2b of the actuator 2, respectively. As a result, the working fluid is supplied to the head-side fluid chamber 2a, and at the same time, the working fluid is discharged from the rod-side fluid chamber 2b, and the piston rod 2r moves in the exit direction. In this way, the spool 30 of the direction switching valve 3 is moved to change the connection state between the main pump 5 and the tank 7 and the head-side fluid chamber 2a and the rod-side fluid chamber 2b of the actuator 2 2 can be operated as desired.

  The remote control valve 4 is a valve for controlling the pilot pressure described above. Here, pilot lines 11 and 12 are connected to the pilot pressure acting portions 51 and 52 of the directional control valve 3, respectively. The remote control valve 4 connects the pilot lines 11 and 12 on the side corresponding to the operating direction of the operating lever 4a and the pilot pump 6 to supply working fluid to the pilot lines 11 and 12. As a result, pilot pressure is generated in the pilot pressure acting portions 51 and 52 connected to the pilot lines 11 and 12. The remote control valve 4 makes the other pilot lines 12, 11 communicate with the tank 7 when the one pilot lines 11, 12 communicate with the pilot pump 6. When the operating lever 4a is not operated, the remote control valve 4 connects both pilot lines 11 and 12 to the tank 7.

  Next, the directional control valve 3 will be described in more detail with reference to FIGS. 2 and 3. FIG. 2 shows a cross section along the longitudinal direction of the spool 30 of the directional control valve 3 shown in FIG. FIG. 3 is a partial cross-sectional view schematically showing the internal passage 70 and the selector 80 formed in the spool 30 shown in FIG.

  The directional control valve 3 shown in FIG. 2 has, as main components, an elongated spool 30 extending along the first direction D1, a valve body 40 provided with a spool hole 41 for accommodating the spool 30, and a valve body 40. And valve covers 53 and 54 attached to both sides of the.

  The valve covers 53 and 54 are tubular members having a connecting portion whose one end in the first direction D1 is connected to the pilot lines 11 and 12. The valve covers 53 and 54 accommodate the other end and one end of the spool 30, respectively. The insides of the valve covers 53 and 54 are connected to the pilot lines 11 and 12, respectively. When the working fluid is supplied to the pilot lines 11 and 12, pilot pressure is generated inside the valve covers 53 and 54, and the pilot pressures are increased. It acts on the other end surface 31 and the one end surface 32 of the spool 30. That is, the interiors of the valve covers 53 and 54 form the pilot pressure acting portions 51 and 52 described above. The other end surface 31 and the one end surface 32 of the spool 30 are pressure receiving surfaces on which the pilot pressure generated inside the valve covers 53 and 54 acts.

  Inside the valve covers 53 and 54, elastic members 61 and 62 that apply an elastic force to the spool 30 toward one side and the other side of the first direction D1 are arranged, respectively. In the illustrated example, the elastic members 61 and 62 are springs.

  A spool hole 41 extending in the first direction D1 is formed in the valve body 40. The spool 30 is movably arranged in the spool hole 41. Various passages including a supply passage 44, an actuator passage 45, and a tank passage 46 are formed in the valve body 40. Although not shown, the valve body 40 is connected to a supply port connected to the main pump 5, a head side actuator port connected to the head side fluid chamber 2a of the actuator 2, and a rod side fluid chamber 2b of the actuator 2. A rod side actuator port and a tank port connected to the tank 7.

  The supply passage 44 communicates with the supply port. In the example shown in FIG. 2, the supply passage 44 is branched midway, one forming the first supply passage 44a and the other forming the second supply passage 44b. The first and second supply passages 44 a and 44 b open into the spool hole 41.

  The actuator passage 45 has a first actuator passage 45a and a second actuator passage 45b. The first and second actuator passages 45a and 45b communicate with the head-side actuator port and the rod-side actuator port, respectively. Therefore, the first actuator passage 45a is connected to the head side fluid chamber 2a of the actuator 2 via the head side actuator port. Further, the second actuator passage 45b is connected to the rod side fluid chamber 2b of the actuator 2 via the rod side actuator port. The first and second actuator passages 45 a and 45 b are also open to the spool hole 41.

  The tank passage 46 communicates with the tank port. In the example shown in FIG. 2, the tank passage 46 is branched midway, one of which constitutes the first tank passage 46a and the other of which constitutes the second tank passage 46b. The first and second tank passages 46 a and 46 b are opened to the spool hole 41, respectively.

  On the inner wall 41a of the spool hole 41, in order from the valve cover 54 side, the opening of the first tank passage 46a, the opening of the first actuator passage 45a, the opening of the first supply passage 44a, and the second supply passage 44b. The opening, the opening of the second actuator passage 45b, and the opening of the second tank passage 46b are formed. An area between the openings of the inner wall 41a of the spool hole 41 forms an annular land portion RL.

  Note that, hereinafter, the annular land portion RL between the opening portion of the first tank passage 46a and the opening portion of the first actuator passage 45a is referred to as a "first tank passage-side annular land portion RL1". Further, the annular land portion RL between the opening of the first actuator passage 45a and the opening of the first supply passage 44a is referred to as a "first supply passage-side annular land portion RL2". The annular land portion RL between the opening of the second supply passage 44b and the opening of the second actuator passage 45b is referred to as a "second supply passage-side annular land portion RL3". Further, the annular land portion RL between the opening of the second actuator passage 45b and the opening of the second tank passage 46b is referred to as a "second tank passage-side annular land portion RL4".

  The spool 30 is a columnar member as a whole, and has a plurality of land portions L arranged apart from each other in the first direction D1 and a plurality of cutout portions M provided between the land portions L. The outer diameter of each land portion L is substantially equal to the inner diameter of the annular land portion RL of the spool hole 41. The outer diameter of each notch M is smaller than the inner diameter of the annular land RL.

  When each land part L is fitted in the corresponding annular land part RL, the internal space of the annular land part RL is closed. As a result, the flow path between the two ports connected to the two passages that open on both sides of the land portion L is blocked. On the other hand, when the land portion L is separated from the corresponding annular land portion RL and the cutout portion M is disposed in the internal space of the annular land portion RL, the operation between the two passages opened on both sides of the annular land portion RL. Fluid flow is allowed. That is, the flow passage between the two ports connected to the two passages is opened. In this way, the spool 30 can change the flow direction of the working fluid by connecting the two ports with the notch M and blocking the two ports with the land L.

  Note that, hereinafter, the land portion L corresponding to the first tank passage-side annular land portion RL1 is referred to as “first tank passage-side land portion L1”. The land portion L corresponding to the first supply passage side annular land portion RL2 is referred to as a "first supply passage side land portion L2". The land portion L corresponding to the second supply passage side annular land portion RL3 is referred to as a "second supply passage side land portion L3". The land portion L corresponding to the second tank passage side annular land portion RL4 is referred to as a "second tank passage side land portion L4". The cutout portion M between the first tank passage side land portion L1 and the first supply passage side land portion L2 is referred to as a "first cutout portion M1". Further, the cutout portion M between the second supply passage side land portion L3 and the second tank passage side land portion L4 is referred to as a "second cutout portion M2".

  Specifically, when the spool 30 is arranged at the neutral position shown in FIG. 2, the first tank passage side land portion L1 is fitted into the first tank passage side annular land portion RL1 and the first actuator passage 45a is formed. And the first tank passage 46a are disconnected from each other. As a result, the flow path that connects the head-side actuator port and the tank port is closed. Further, the first supply passage side land portion L2 is fitted to the first supply passage side annular land portion RL2 to cut off the connection between the first actuator passage 45a and the first supply passage 44a. As a result, the flow path that connects the head-side actuator port and the supply port is closed. In addition, the second tank passage side land portion L4 is fitted to the second tank passage side annular land portion RL4 to block between the second actuator passage 45b and the second tank passage 46b. As a result, the flow path that connects the rod-side actuator port and the tank port is closed. In addition, the second supply passage side land portion L3 is fitted to the second supply passage side annular land portion RL3 to cut off between the second actuator passage 45b and the second supply passage 44b. As a result, the flow path that connects the rod-side actuator port and the supply port is closed. As described above, the working fluid from the main pump 5 connected to the supply port is not supplied to any of the fluid chambers 2a and 2b of the actuator 2. Further, the working fluid in any of the fluid chambers 2a and 2b of the actuator 2 is not discharged to the tank 7 connected to the tank port. Therefore, the actuator 2 does not operate and its posture is maintained.

  When the spool 30 is moved in the spool hole 41 from the neutral position shown in FIG. 2 to one side in the first direction (right side in FIG. 2) to the first operating position, the first tank passage-side land portion L1 is located in the first tank passage. A first cutout portion M1 is disposed in the internal space of the first tank passage-side annular land portion RL1 which is separated from the side annular land portion RL1. As a result, the first actuator passage 45a and the first tank passage 46a communicate with each other through the space between the first cutout portion M1 and the first tank passage-side annular land portion RL1. Therefore, the flow path connecting the head side actuator port and the tank port is opened. At this time, the first supply passage side land portion L2 is still fitted to the first supply passage side annular land portion RL2, and the first supply passage 44a and the first actuator passage 45a are not blocked. Up to. Therefore, the flow path connecting the head-side actuator port and the supply port remains closed. Further, the second supply passage side land portion L3 is separated from the second supply passage side annular land portion RL3, and the second cutout portion M2 is arranged in the internal space of the second supply passage side annular land portion RL3. As a result, the second actuator passage 45b and the second supply passage 44b communicate with each other through the space between the second cutout portion M2 and the second supply passage-side annular land portion RL3. Therefore, the flow path connecting the rod-side actuator port and the supply port is opened. At this time, the second tank passage-side land portion L4 remains fitted in the second tank passage-side annular land portion RL4, and the second actuator passage 45b and the second tank passage 46b remain blocked. is there. Therefore, the flow path connecting the rod-side actuator port and the tank port remains closed. As described above, the working fluid from the main pump 5 connected to the supply port enters the rod side fluid chamber 2b through the second supply passage 44b, the internal space of the second supply passage side annular land portion RL3 and the second actuator passage 45b. Inflow. Further, the working fluid in the head side fluid chamber 2a flows into the tank 7 through the first actuator passage 45a, the internal space of the first tank passage side annular land portion RL1 and the first tank passage 46a. As a result, the piston rod 2r of the actuator 2 moves in the pulling direction.

  When the spool 30 is moved from the neutral position shown in FIG. 2 to the other side (left side in FIG. 2) of the first direction D1 in the spool hole 41 to the second operating position, the first supply passage side land portion L2 is used for the first supply. A first cutout portion M1 is disposed in the internal space of the first supply passage-side annular land portion RL2, which is separated from the passage-side annular land portion RL2. As a result, the first actuator passage 45a and the first supply passage 44a communicate with each other through the space between the first cutout portion M1 and the first supply passage-side annular land portion RL2. Therefore, the flow path connecting the head side actuator port and the supply port is opened. At this time, the first tank passage side land portion L1 remains fitted in the first tank passage side annular land portion RL1, and the first actuator passage 45a and the first tank passage 46a remain blocked. is there. Therefore, the flow path connecting the head-side actuator port and the tank port remains closed. Further, the second tank passage side land portion L4 is separated from the second tank passage side annular land portion RL4, and the second cutout portion M2 is disposed in the internal space of the second tank passage side annular land portion RL4. As a result, the second actuator passage 45b and the second tank passage 46b communicate with each other through the space between the second cutout portion M2 and the second tank passage-side annular land portion RL4. Therefore, the flow path connecting the rod-side actuator port and the tank port is opened. At this time, the second supply passage side land portion L3 remains fitted in the second supply passage side annular land portion RL3, and the second actuator passage 45b and the second supply passage 44b remain blocked. is there. Therefore, the flow path connecting the rod-side actuator port and the supply port remains closed. As described above, the working fluid from the main pump 5 connected to the supply port passes through the first supply passage 44a, the internal space of the first supply passage-side annular land portion RL2, and the first actuator passage 45a, and the head-side fluid chamber. Flows into 2a. The working fluid in the rod-side fluid chamber 2b flows into the tank 7 via the second actuator passage 45b, the internal space of the second tank passage-side annular land portion RL4, and the second tank passage 46b. As a result, the piston rod 2r of the actuator 2 moves in the exit direction.

  In such a direction switching valve, for example, when the working fluid is discharged from the head side fluid chamber 2a of the actuator 2 to retract the rod 2r, the first tank passage side annular land portion RL1 to the first tank passage side land portion L1 are If the flow path connecting the head-side actuator port and the tank port is opened only after the actuator is detached, the actuator 2 may suddenly operate to generate shock and vibration. In order to prevent such a situation, it is known to provide a notch extending in the spool movement direction on the outer peripheral surface of the land portion. That is, when the spool is moved, before the land portion is separated from the annular land portion, the passages that open on both sides of the annular land portion are communicated with each other through the notches so that the so-called working fluid flows from one passage to the other passage. Cause a pre-flow of. With this, the actuator can start the operation before the land part is separated from the annular land part, and it is possible to prevent the occurrence of vibration and impact due to the abrupt operation of the actuator.

  In the example shown in FIGS. 2 and 3, the notch N is provided on the outer peripheral surface of the first tank passage side land portion L1. 3, the notch N is elongated in the moving direction D1 of the spool 30 and extends from the end of the first tank passage side land portion L1 on the first actuator passage 45a side to the first tank passage 46a side. Extends to. Since the notch N is provided on the outer peripheral surface of the first tank passage side land portion L1, the spool 30 moves to one side in the first direction D1 (right side in FIG. 2) and the first tank passage side land portion L1. The first actuator passage 45a and the first tank passage 46a are communicated with each other through the notch N before the second actuator separates from the first tank passage-side annular land portion RL1. A pre-flow of working fluid through N can occur. That is, the working fluid can be discharged little by little from the first actuator passage 45a to the first tank passage 46a through the notch N. In the following, the first tank passage-side land portion from the position where the internal space of the first tank passage-side annular land portion RL1 is closed to the position where the inner space of the first tank passage-side land portion L1 is closed than the notch N is opened. A portion on the front side (right side in FIG. 2) in the moving direction of L1 (spool 30) (right direction in FIG. 2) is referred to as a notch non-forming portion L1a.

  Here, as shown in FIG. 3, when the spool 30 is in the neutral position, the internal space of the first tank passage side annular land portion RL1 is closed by the notch non-forming portion L1a of the first tank passage side land portion L1. ing. Therefore, when the spool 30 is in the neutral position, there is no pre-flow of working fluid through the notch N. The pre-flow of the working fluid through the notch N starts when the spool 30 moves to one side (the right side in FIG. 3) of the first direction D1 and one end of the notch N faces the first tank passage 46a. . This causes the actuator 2 to start operating. The forward flow of the working fluid through the notch N continues until the first tank passage side land portion L1 separates from the first tank passage side annular land portion RL1.

  By the way, generally, such a notch has a sufficient length so that the operating speed of the actuator does not suddenly change before and after the land portion is separated from the annular land portion. That is, since the notch has a sufficient length, it is possible to gradually increase the opening area of the flow passage that connects the passages that open on both sides of the annular land portion as the spool moves. The amount of working fluid discharged from the fluid chamber is gradually increased, and the operating speed of the actuator can be gradually increased. On the other hand, the notch having a sufficient length causes the following problems. First, the longer the notch N is, the more the notch forming portion L1a of the land portion L1 and the annular land portion RL1 overlap each other along the moving direction D1 of the spool 30 when the spool 30 is in the neutral position. The length W (hereinafter referred to as “overlap amount”) W becomes shorter. If the overlap amount W is short, even if the spool 30 is arranged in the neutral position to maintain the posture of the actuator 2, one side (the passage 45a side) of the annular land portion RL1 to the other side (the passage 46a side). ), The working fluid leaks out, and the posture of the actuator 2 cannot be maintained.

  In consideration of such a point, in the illustrated example, the length of the notch N is set shorter than in the conventional case, and the overlap amount W when the spool 30 is in the neutral position is set larger than in the conventional case.

  By the way, generally, when the overlap amount or the notch length is changed, the controllability of the actuator is also changed. For example, even if the operation lever of the remote control valve is operated as in the conventional case, the time length from the start of the operation of the operation lever to the start of the pre-flow of the working fluid is different from the conventional time. The time length from the start of the operation of 1 to the start of the operation of the actuator is also different from the conventional one. In addition, when the length of the notch is shortened, the length of time during which the forward flow of the working fluid is continued becomes shorter than in the conventional case, so that the actuator cannot be sufficiently operated before the land portion is separated from the annular land portion. Further, in this case, since the maximum opening area due to the notch of the passage to which the notch connects is smaller than that in the conventional case, the operating speed of the actuator cannot be made sufficiently high before the land part separates from the annular land part. This makes the operator of the operating lever feel uncomfortable.

  In consideration of such circumstances, the directional control valve 3 of the present embodiment has a sufficient overlap amount W between the first tank passage side land portion L1 and the first tank passage side annular land portion RL1 at the neutral position. The device is designed to maintain the controllability of the actuator 2 while setting it large.

  Specifically, the directional control valve 3 has an internal passage 70 that communicates with the head-side actuator port and the tank port via the head-side actuator passage 45a and the first tank passage 46a. The internal passage 70 is closed when the spool 30 is in the neutral position, but is opened when the spool 30 moves from the neutral position to the first operating position. By causing the pre-flow of the working fluid through the internal passage 70, it is possible to maintain the controllability of the actuator 2 while setting the overlap amount W sufficiently large.

  Hereinafter, the internal passage 70 and its opening / closing mechanism will be described in detail with reference to FIGS. 2 to 5. 4 is a partial front view showing the outer peripheral surface of the spool 30 in the vicinity of the first cutout portion M1, and FIG. 5 is a sectional view taken along the line I-I of FIG. 4 and 5, the selector 80 and the elastic member 85, which will be described later, are not shown.

  As shown in FIGS. 2 to 5, the spool 30 is formed with a selector hole 71 that accommodates the selector 80. As shown in FIG. 3, the selector hole 71 extends in the first direction D1 from the first tank passage side land portion L1 to the first supply passage side land portion L2. One end of the selector hole 71 is closed by a plug 75. Further, the spool 30 is formed with a first hole 72 opening on the first tank passage side land portion L1 and a second hole 73 opening on the first cutout portion M1. As shown in FIGS. 3 and 5, the first hole 72 and the second hole 73 respectively extend in the radial direction D2 of the spool 30 and open on the inner peripheral surface of the selector hole 71. Note that, hereinafter, the opening of the first hole 72 provided on the outer peripheral surface of the first tank passage side land L1 is referred to as an “outer opening 72a of the first hole 72”, and the inner circumference of the selector hole 71 is called. The opening of the first hole 72 provided on the surface is referred to as an “inner opening 72b of the first hole 72”. Similarly, the opening of the second hole 73 provided on the outer peripheral surface of the first cutout portion M1 is referred to as an “outer opening 73a of the second hole 73” and is provided on the inner peripheral surface of the selector hole 71. The opening of the second hole 73 is referred to as an “inner opening 73b of the second hole 73”.

  The first hole 72 and the second hole 73 are communicated with each other by the selector hole 71. The first hole 72 and the second hole 73, together with the selector hole 71, form the internal passage 70. The first hole 72 and the second hole 73 form one end and the other end of the internal passage 70, respectively. Such an internal passage 70 has one end (first hole 72) whose first tank passage side land portion L1 is the first tank passage side annular land portion when the spool 30 moves from the neutral position to the first operating position. Before it separates from RL1 and the internal space of the annular land portion RL1 is opened, it faces the first tank passage 46a.

  As shown in FIG. 3, the outer opening 72a of the first hole 72 is provided at a position facing the first tank passage side annular land RL1 when the spool 30 is at the neutral position. Therefore, when the spool 30 is in the neutral position, the internal passage 70 is closed by the first tank passage-side annular land portion RL1.

  In the spool 30, a working fluid hole 74 extending in the first direction D1 is formed on the other side of the selector hole 71 in the first direction D1. The working fluid hole 74 opens on the pressure receiving surface 31 of the spool 30 on the pilot pressure acting portion 51 side and communicates with the selector hole 71. As a result, the working fluid supplied to the pilot pressure acting portion 51 can flow into the selector hole 71 through the working fluid hole 74.

  Further, the plug body 75 closing one end of the selector hole 71 in the first direction D1 is formed with a sub working fluid hole 76 penetrating the plug body 75 in the first direction D1. The auxiliary working fluid hole 76 opens to the pressure receiving surface 32 of the spool 30 on the pilot pressure acting portion 52 side, and communicates with the selector hole 71. As a result, the working fluid in the selector hole 71 can be discharged to the pilot pressure acting portion 52 through the sub working fluid hole 76.

  The internal passage 70 described above is also opened and closed by the selector 80 housed in the selector hole 71. Hereinafter, the selector 80 will be described in detail.

  The selector 80 opens and closes the internal passage 70 formed in the spool 30 by moving with respect to the spool 30. More specifically, the inner passage 70 is opened and closed between the first hole 72 and the second hole 73.

  In the illustrated example, the selector 80 is a columnar member as a whole and extends in the first direction D1. The selector 80 connects the first large diameter portion 81 facing the plug 75, the second large diameter portion 82 facing the working fluid hole 74, and the first large diameter portion 81 and the second large diameter portion 82. And a small diameter portion 83. The outer diameters of the first and second large diameter portions 81 and 82 match the inner diameter of the selector hole 71. The outer diameter of the small diameter portion 83 is smaller than the inner diameter of the selector hole 71. The other end surface 84 of the selector 80 facing the working fluid hole 74 is a pressure receiving surface. The pressure receiving surface 84 receives the pressure of the working fluid flowing from the pilot pressure acting portion 51 through the working fluid hole 74 into the selector hole 71.

  An elastic member 85 that presses the selector 80 toward the other side in the first direction D1 is housed between the selector 80 and the plug 75. In the illustrated example, the elastic member 85 is a spring. As a result, when the pressure receiving surface 84 of the selector 80 is not loaded with pressure, as shown in FIG. 3, the selector 80 is located at a position most distant from the plug 75 (thus, at a position closest to the working fluid hole 74). Retained. When pressure is applied to the pressure receiving surface 84, the pressure receiving surface 84 moves in the selector hole 71 toward the one side in the first direction D1 with respect to the spool 30. That is, when the working fluid is supplied to the pilot pressure acting portion 51, the selector 80 moves toward the stopper 75 against the pressing force of the elastic member 85.

  The pressure applied to the pressure receiving surface 84 of the selector 80 to move the selector 80 is the pressure due to the working fluid supplied to the pilot pressure acting portion 51 to move the spool 30. That is, the selector 80 moves by the action of the working fluid that moves the spool 30.

  Here, when the working fluid is not supplied to the pilot pressure acting portion 51 and the spool 30 is in the neutral position, the selector 80 is held at the position most distant from the plug 75 by the pressing force of the elastic member 85. At this time, as shown in FIG. 3, the first large diameter portion 81 of the selector 80 has the inner opening 72b of the first and second holes 72, 73 on the inner peripheral surface of the selector hole 71 in the first direction D1. The first hole 72 and the second hole 73 are closed by fitting in a portion (hereinafter, referred to as “selector hole annular land portion SRL”) located between 73b. That is, the selector 80 closes the internal passage 70.

      When the working fluid is supplied to the pilot pressure acting portion 51, the working fluid of the pilot pressure acting portion 51 flows into the working fluid hole 74, and the pressure of the working fluid is applied to the pressure receiving surface 84 of the selector 80. When the working fluid acts on the pressure receiving surface 84, the selector 80 moves with respect to the spool 30 so as to approach the stopper 75. As a result, as shown in FIG. 6, the first large diameter portion 81 of the selector 80 separates from the selector hole annular land portion SRL, and the small diameter portion 83 is arranged in the internal space of the selector hole annular land portion SRL. In this way, the internal space of the selector hole annular land portion SRL is opened (thus, between the first hole 72 and the second hole 73). That is, the selector 80 opens the internal passage 70.

  Thus, the selector 80 opens and closes the internal passage 70 under the action of the pressing force of the elastic member 85 and the working fluid flowing into the working fluid hole 74. When the working fluid flows into the pilot pressure acting portion 51 and the selector 80 moves, the pilot pressure is applied to the pressure receiving surface 31 of the spool 30 on the pilot pressure acting portion 51 side. Therefore, the spool 30 moves with respect to the valve body 40 toward one side in the first direction D1. That is, the selector 80 moves with respect to the spool 30 and opens the internal passage 70 when the spool 30 moves toward one side of the first direction D1 (in other words, with the movement of the spool 30). . In this way, the internal passage 70 is closed when the spool 30 is in the neutral position and opened when the spool 30 is moved from the neutral position, so that the working fluid is supplied to one side of the internal passage 70 when the spool 30 is in the neutral position. Leakage through the internal passage 70 from the side (the side of the passage 45a) to the other side (the side of the passage 46a) is reduced, while the operation through the internal passage 70 is performed when the spool 30 moves from the neutral position. A pre-flow of fluid can occur.

  Further, in the illustrated example, as described above, when the spool 30 is in the neutral position, the internal passage 70 is also opened / closed by the annular land portion RL1 with which the land portion L1 is fitted. More specifically, the outer opening 72a of the first hole 72 is closed by the annular land RL1. The outer opening 72a is opened when the spool 30 moves from the neutral position toward one side of the first direction D1 (in other words, with the movement of the spool 30). That is, the land portion L1 opens the internal passage 70 as the spool 30 moves. As a result, it is more effective that the working fluid leaks from one side of the internal passage 70 (the side of the passage 45a) to the other side (the side of the passage 46a) through the internal passage 70 when the spool 30 is in the neutral position. However, when the spool 30 moves from the neutral position, a forward flow of the working fluid through the internal passage 70 can be generated.

  Further, in the illustrated example, the pressing force of the elastic member 85 is released so that the internal passage 70 of the spool 30 is released before the first tank-side land portion L1 is separated from the first tank-side annular land portion RL1 ( In other words, the flow paths 45a, 41, and 46a in the valve body 40 connecting the head-side actuator port and the tank port are opened prior to the opening). This allows a pre-flow of working fluid through the internal passage 70. In this case, when the spool 30 moves to one side in the first direction D1, the passages 45a and 46a are first connected by the internal passage 70 and then further connected by the internal space of the first tank passage-side annular land portion RL1. Like Therefore, it is possible to gradually increase the opening area of the flow path connecting the two ports communicating with the passages 45a and 46a. By gradually increasing the opening area of the flow path connecting the two ports, the flow rate of the working fluid flowing out from the fluid chamber 2a of the actuator 2 per unit time is gradually increased to increase the operating speed of the actuator 2. Can be gradually faster. As a result, it is possible to prevent the actuator 2 from suddenly operating and causing vibration and impact.

  In the illustrated example, the pressing force of the elastic member 85 is adjusted so that the selector 80 moves in the selector hole 71 to open the internal passage 70 before the movement of the spool 30 starts. Thereby, the pre-flow of the working fluid through the internal passage 70 can be generated more reliably. Therefore, it is possible to more reliably increase the opening area of the flow path connecting the two ports communicating with the passages 45a and 46a.

  In addition, as described above, the notch N is provided in the first tank-side land portion L1. As described above, the length of the notch N in the first direction D1 is shorter than the conventional one. Therefore, the time length from the operation of the operation lever 4a to the start of the pre-flow of the working fluid through the notch N is longer than in the conventional case. Therefore, in the example shown in FIGS. 3 and 4, the first hole 72 of the internal passage 70 is formed so that the pre-flow of the working fluid through the internal passage 70 starts before the pre-flow of the working fluid through the notch N starts. It is provided in the position like. That is, the first hole 72 moves the first tank passage-side land portion L1 (of the spool 30) from the position where the inner space of the first tank passage-side annular land portion RL1 is closed to the position where the first hole 72 is opened, rather than the notch N. The first tank passage side land portion L1 is opened at a position on the front side (right side in FIGS. 2 and 3) in the direction (right direction in FIGS. 2 and 3). Thus, when the spool 30 moves from the neutral position to the first operating position, one end (first hole 72) of the internal passage 70 faces the first tank passage 46a before one end of the notch N. . Therefore, the pre-flow of the working fluid through the internal passage 70 occurs before the pre-flow of the working fluid through the notch N. Therefore, even if the length of the notch N becomes shorter than in the conventional case, the working fluid is transferred from the first actuator passage 45a side to the first tank passage 46a side in the same length of time as in the conventional case after the operation lever 4a is operated. The operation of the actuator 2 can be started by starting the pre-flow. Further, the maximum opening area of the notches N of the passages 45a and 46a and the internal passage 70 can be made similar to the maximum opening area of the conventional long notch. That is, the operating speed of the actuator 2 can be increased to the same level as in the conventional case before the land portion is separated from the annular land portion. In this way, the operability of the actuator 2 through the direction switching valve 3 is maintained as in the conventional case.

  Further, since the notch N is provided at a position on the rear side (left side in FIGS. 2 and 3) in the moving direction of the spool 30 with respect to one end of the internal passage 70, a flow connecting the two ports is formed. The opening area of the passage can be increased more smoothly. That is, the opening area of the flow path connecting the above two ports is calculated from the opening area of the flow paths 45a, 70, 46a and the opening area of the flow paths 45a, 70, 46a and the opening areas of the flow paths 45a, N, 46a. , And the sum of the opening areas of the flow paths 45a, 70, 46a, the opening areas of the flow paths 45a, N, 46a, and the opening areas of the flow paths 45a, 41, 46a. As a result, the operating speed of the actuator 2 controlled via the direction switching valve 3 can be increased more smoothly. Therefore, excellent operability of the actuator 2 can be provided.

  Further, in the example shown in FIGS. 3 and 4, the first hole 72 is opened at a position that partially overlaps the notch N in the moving direction D1 of the spool 30 (left and right direction in FIGS. 3 and 4). Thus, when the spool 30 moves from the neutral position to the first operating position, one end (first hole 72) of the internal passage 70 and one end of the notch N continuously face the first tank passage 46a. Come to do. In this case, when the spool 30 moves to one side in the first direction D1, the passages 45a and 46a are first connected by the internal passage 70, continuously connected by the notch N, and further continuously by the first tank passage side. It is connected by the internal space of the annular land portion RL1. Therefore, the opening area of the flow path connecting the two ports communicating with the passages 45a and 46a can be continuously increased. By continuously increasing the opening area of the flow path connecting the two ports, the flow rate of the working fluid flowing out of the fluid chamber 2a of the actuator 2 per unit time can be continuously increased. Therefore, more excellent operability of the actuator 2 can be provided. In this case, as shown in FIG. 5, the outer opening 72a of the first hole 72 is opened at a position displaced from the notch N in the circumferential direction D3 about the moving direction D1 of the spool 30. It should be provided.

  Next, the operation of the directional control valve 3 will be described with reference to FIGS. 1 to 3 and 6 to 9. The operation of the directional control valve 3 when the spool is moved from the neutral position shown in FIGS. 2 and 3 to the first operating position will be described below.

  First, when the operation lever 4a of the remote control valve 4 is not operated, the pilot lines 11 and 12 are both in communication with the tank 7. Therefore, the working fluid is not supplied from the pilot pump 6 to the pilot lines 11 and 12, and no pilot pressure is generated in any of the pilot pressure acting portions 51 and 52. Therefore, the pilot pressure does not act on the spool 30, and the spool 30 is held at the neutral position shown in FIGS. 1 and 2 by the elastic force of the elastic members 61 and 62. At this time, as well shown in FIG. 3, the first tank passage side land portion L1 is fitted to the first tank passage side annular land portion RL1.

  In addition, since the overlap amount W between the first tank passage side land portion L1 and the first tank passage side annular land portion RL1 is set to be sufficiently large, it has flowed into the notch N from the first actuator passage 45a side. Leakage of the working fluid to the first tank passage 46a side is reduced.

  Further, the internal passage 70 is provided in the spool 30, but the internal passage 70 is closed because the first large diameter portion 81 of the selector 80 is fitted in the internal space of the selector hole annular land portion SRL. ing. Therefore, the working fluid that has flowed into the other end (second hole 73) of the internal passage 70 from the first actuator passage 45a side is prevented from leaking to the first tank passage 46a side. Further, one end of the internal passage 70 (more specifically, the outer opening 72a of the first hole 72) is closed by the first tank passage-side annular land portion RL1. As a result, the working fluid flowing from the first actuator passage 45a side to the other end (second hole 73) of the internal passage 70 is further effectively reduced from leaking to the first tank passage 46a side.

  As described above, when the spool 30 is at the neutral position shown in FIGS. 2 and 3, the working fluid is prevented from flowing out from the head side fluid chamber 2a of the actuator 2, and the posture of the actuator 2 is maintained.

  Next, when moving the spool 30 from the neutral position to the first operating position, the operating lever 4a of the remote control valve 4 is operated to make the pilot pump 6 and the pilot line 11 communicate with each other, and the pilot pump 6 to the pilot line 11 is connected. Supply working fluid. The working fluid supplied to the pilot line 11 flows into the valve cover 53. As a result, a pilot pressure corresponding to the operation amount of the operation lever 4a is generated in the valve cover 53.

  The working fluid that has flowed into the valve cover 53 flows into the working fluid hole 74 that is opened in the pressure receiving surface 31 of the spool 31, and acts on the pressure receiving surface 84 of the selector 80. As a result, as shown in FIG. 6, the selector 80 resists the elastic force of the elastic member 85 to one side of the spool 30 in the first direction D1 (on the right side in FIG. 2) and to the plug body 75. Move towards. Then, the small diameter portion 83 of the selector 80 is arranged in the internal space of the selector hole annular land SRL. As a result, one end (first hole 72) and the other end (second hole 73) of the internal passage 70 communicate with each other. When the selector 80 moves toward the plug 75, the working fluid contained in the space between the selector 80 and the plug 75 in the selector hole 71 is the auxiliary working fluid penetrating the plug 75. It is discharged to the pilot pressure acting portion 52 through the hole 76.

  After the selector 80 moves toward the plug body 75 and one end (first hole 72) and the other end (second hole 73) of the internal passage 70 communicate with each other, the spool 30 is connected to the valve as shown in FIG. Due to the action of the pilot pressure in the cover 53, the elastic member 62 moves toward one side (the right side in FIG. 3) in the first direction D1 against the elastic force of the elastic member 62. As a result, the outer opening 72a of the first hole 72 of the internal passage 70 faces the first tank passage 46a, and the first actuator passage 45a and the first tank passage 46a communicate with each other through the internal passage 70. This causes a pre-flow of the working fluid through the internal passage 70 from the first actuator passage 45a to the first tank passage 46a. As a result, the working fluid in the head-side fluid chamber 2a of the actuator 2 flows out, and the actuator 2 starts operating. Specifically, the rod 2r starts moving so as to retract.

  Subsequently, as shown in FIG. 8, when the spool 30 further moves toward one side of the first direction D1 (right side of FIG. 3) by the action of the pilot pressure in the valve cover 53, one side end of the notch N. The portion faces the first tank passage 46a. As a result, the first actuator passage 45a and the first tank passage 46a communicate not only with the internal passage 70 but also with the notch N. As a result, a pre-flow of the working fluid through the notch N occurs from the first actuator passage 45a to the first tank passage 46a. Since the first actuator passage 45a and the first tank passage 46a communicate with each other by the notch N, the opening area of the passage that connects the passages 45a and 46a is increased. As a result, the flow rate of the working fluid flowing out of the head-side fluid chamber 2a of the actuator 2 per unit time increases, and the actuator 2 accelerates its operating speed. Specifically, the retracting speed of the rod 2r is further increased. The opening area of the flow path that connects the passages 45a and 46a is such that the portion of the notch N facing the first tank passage 46a along with the movement of the spool to one side in the first direction D1 (right side in FIG. 3). It increases as it increases. As a result, the flow rate of the working fluid flowing out of the head side fluid chamber 2a per unit time also increases.

  Then, as shown in FIG. 9, the spool 30 further moves toward one side of the first direction D1 (right side in FIG. 3), and the first tank passage side land portion L1 becomes the first tank passage side annular land portion. When separated from RL1, the first actuator passage 45a and the first tank passage 46a communicate with each other through the internal space of the first tank passage-side annular land portion RL1. Since the first actuator passage 45a and the first tank passage 46a are also communicated with each other by the internal space of the annular land portion RL1, the opening area of the passage connecting the passages 45a and 46a is further increased. As a result, the flow rate of the working fluid flowing out of the head-side fluid chamber 2a of the actuator 2 per unit time is further increased, and the operating speed of the actuator 2 is further increased. Specifically, the retracting speed of the rod 2r is further increased.

  As described above, the operating speed of the actuator 2 can be gradually increased by gradually increasing the outflow amount of the working fluid from the head-side fluid chamber 2a per unit time. As a result, it is possible to prevent the actuator 2 from suddenly operating to generate vibration or impact.

  In the present embodiment described above, the case where both the notch N and the internal passage 70 are provided in the spool 30 has been described. However, the present invention is not limited to this, and the notch N may not be provided in the spool 30. In this case as well, a pre-flow of the working fluid is generated through the internal passage 70, so that it is possible to prevent the occurrence of shock or vibration due to the sudden operation of the actuator 2.

  The directional control valve 3 according to the present embodiment described above is provided in the valve main body 40 by moving with respect to the valve main body 40 provided with two ports, and the two ports described above. A spool 30 for opening and closing the connecting flow paths 45, 41, 46, the spool 30 having an internal passage 70 that opens and closes as the valve body 40 moves and communicates with the two ports. .

  According to such a directional control valve 3, a forward flow of the working fluid can be generated through the internal passage 70. Therefore, it is possible to prevent the actuator 2 controlled through the direction switching valve 3 from suddenly operating to generate shock and vibration. On the other hand, since the internal passage 70 is opened and closed with the movement of the spool 30, when the spool 30 is in the predetermined position, the internal passage 70 is closed and the internal passage 70 is passed through inside the directional control valve 3. It is possible to reduce the occurrence of leakage of the working fluid.

  Further, according to such a directional control valve 3, the present embodiment can be simply and inexpensively performed by simply replacing the spool of the conventional directional control valve with the spool 30 described above, that is, without changing the valve body. The directional control valve 3 of the form can be realized. Moreover, the directional control valve 3 does not increase in size.

  More specifically, the internal passage 70 of the spool 30 opens and closes as the selector 80 moves.

  Further, in the present embodiment, the selector 80 moves along with the movement of the spool 30 with respect to the valve body 40. In this case, it is easy to open and close the internal passage 70 as the spool 30 moves with respect to the valve body 40.

  Further, in the present embodiment, the internal passage 70 of the spool 30 is opened before the flow passages 45a, 41, 46a in the valve body 40. In this case, the opening area of the flow path connecting the two ports is gradually increased (that is, from the opening areas of the flow paths 45a, 70, 46a to the opening areas of the flow paths 45a, 70, 46a and the flow path). The operating speed of the actuator 2 controlled via the directional control valve 3 can be gradually increased (increasing to the sum of the opening areas of 45a, 41 and 46a). Therefore, it is possible to prevent the actuator 2 from suddenly operating to generate shock and vibration.

  Further, in the present embodiment, the internal passage 70 of the spool 30 is opened by the action of the working fluid that moves the spool 30. In this case, with a simple configuration, the internal passage 70 can be opened and closed as the spool 30 moves.

  More specifically, the selector 80 moves by the action of the working fluid that moves the spool 30. Accordingly, the selector 80 can be moved to open and close the internal passage 70 without involving a complicated mechanism. Further, it is easy to move the selector 80 along with the movement of the spool 30 with respect to the valve body 40.

  Further, in the present embodiment, the internal passage 70 of the spool 30 is opened before the movement of the spool 30 is started. In this case, it can be ensured that the opening area of the flow path connecting the two ports is gradually increased.

  Further, in the present embodiment, the spool 30 has a cutout portion M1 that connects the two ports and a land portion L1 that blocks the two ports, and the movement of the spool 30 on the land portion L1. An elongated notch N is provided in the direction D1, and one end of the internal passage 70 is moved from the position where the flow passages 45a, 41, 46a in the valve body 40 are closed to the position where the spool 30 is moved to an open position rather than the notch N. It opens on the land portion L1 at a position on the front side.

  In this case, in order to reduce the leakage of the working fluid through the notch N inside the direction switching valve 3, the length of the notch N is made shorter than in the conventional case, and the land portion L1 and the land portion L1 are fitted together. Even if the overlap amount W with the annular land portion RL1 is set large, the controllability of the actuator 2 can be maintained as in the conventional case. Specifically, in this case, when the spool 30 moves to the front side, one end of the internal passage 70 faces the passage 46a before the notch N. Therefore, the pre-flow of the working fluid through the internal passage 70 can be generated before the pre-flow of the working fluid through the notch N occurs. Therefore, even if the length of the notch N is shorter than that of the conventional one, the forward flow of the working fluid can be started in the same length of time as that of the conventional one after operating the operation lever 4a, and the operation of the actuator 2 is started. Can be made. Further, even if the length of the notch N is shorter than that of the conventional one, the maximum opening area due to the notch N of the flow path connecting the two ports and the internal passage 70 (that is, the maximum opening area of the flow paths 45a, N, 46a is The sum of the maximum open areas of the flow paths 45a, 70, 46a) can be made similar to the maximum open area of a conventional long notch. That is, the operating speed of the actuator 2 can be increased to the same level as in the conventional case before the land portion L1 is separated from the annular land portion RL1. In this way, the operability of the actuator 2 through the direction switching valve 3 can be maintained as in the conventional case.

  Further, since the notch N is provided at a position on the rear side of the one end of the internal passage 70 when the spool 30 moves, the opening area of the flow path connecting the two ports can be made smoother. Can be increased. That is, from the opening areas of the channels 45a, 70, 46a to the sum of the opening areas of the channels 45a, 70, 46a and the opening areas of the channels 45a, N, 46a, and the openings of the channels 45a, 70, 46a. It can be increased to the sum of the area and the opening area of the channels 45a, N, 46a and the opening areas of the channels 45a, 41, 46a. As a result, the operating speed of the actuator 2 controlled via the direction switching valve 3 can be increased more smoothly. Therefore, excellent operability of the actuator can be provided.

  Further, in the present embodiment, one end of the internal passage 70 is opened at a position that partially overlaps the notch N in the moving direction D1 of the spool 30. In this case, the opening area of the flow path connecting the two ports can be continuously increased, and the operating speed of the actuator 2 can be continuously increased. That is, it is possible to provide more excellent actuator operability.

  Further, in the present embodiment, one end of the internal passage 70 opens at a position displaced from the notch N in the circumferential direction D3 centered on the moving direction D1 of the spool 30. In this case, the notch N and the opening position of the internal passage 70 can be overlapped in the axial direction of the spool 30 with a simple configuration.

  The present invention is not limited to the above embodiments. For example, various modifications may be added to each element of the above-described embodiment. Further, forms including components and / or methods other than the components and / or methods described above are also included in the embodiments of the present invention. Further, a mode in which some of the components and / or methods described above are not included is also included in the embodiments of the present invention. Further, the effects produced by the present invention are not limited to the above-mentioned effects, and peculiar effects according to the specific configurations of the respective embodiments can be exhibited.

1 Working Fluid Circuit 2 Actuator 2a Head Side Fluid Chamber 2b Rod Side Fluid Chamber 3 Directional Change Valve 4 Remote Control Valve 30 Spool 40 Valve Body 44 Supply Passage 44a First Supply Passage 45 Actuator Passage 45a First Actuator Passage 46 Tank Passage 46a 1st Tank passages 61, 62 Elastic member 70 Internal passage 71 Selector hole 74 Working fluid hole 75 Plug 80 Selector 85 Elastic member L Land portion L1 First tank passage side land portion L2 First supply passage side land portion M Notch portion M1 First Notch portion N1 First notch RL Annular land portion RL1 First tank passage-side annular land portion RL2 First supply passage-side annular land portion

Claims (10)

A valve body provided with two ports,
A spool that is provided in the valve body and that opens and closes a flow path that connects the two ports, the spool having an internal passage that is opened and closed with movement of the valve body and that communicates with the two ports, Directional switching valve equipped with.   The directional control valve according to claim 1, wherein the internal passage of the spool is opened prior to the flow passage in the valve body.   The directional control valve according to claim 1 or 2, wherein the internal passage of the spool is opened by an action of a working fluid that moves the spool.   The directional control valve according to claim 3, wherein the internal passage of the spool is opened before the movement of the spool is started.   The directional control valve according to any one of claims 1 to 4, wherein the internal passage of the spool is opened / closed as the selector moves.   The directional control valve according to claim 5, wherein the selector moves along with the movement of the spool with respect to the valve body.   7. The directional control valve according to 5 or 6, wherein the selector moves by an action of a working fluid that moves the spool. The spool has a cutout portion that connects the two ports, and a land portion that blocks the two ports,
The land portion is provided with an elongated notch in the moving direction of the spool,
One end of the internal passage opens on the land portion at a position that is on the front side when the spool moves from a position that closes the flow passage in the valve body to a position that opens the flow passage in the valve body rather than the notch. The directional control valve according to any one of claims 1 to 7.   9. The direction switching valve according to claim 8, wherein the one end of the internal passage is opened at a position that partially overlaps the notch in the moving direction of the spool.   The directional control valve according to claim 8 or 9, wherein the one end of the internal passage opens at a position displaced from the notch in a circumferential direction centered on a moving direction of the spool.