JPH07167317A - Directional changeover control valve - Google Patents

Abstract

PURPOSE:To loosen shock generated when a spool is operated from an ogirinal position to a fluid pressure supply position, and secure speedy reset of the spool to the original position. CONSTITUTION:A first damper member 42 and a second damper member 44 are arranged between one end of a spool 20 and a pilot port 12B, while a damper chamber is formed between both members. The first damper member 42 is abutted against the spool 20 until the spool 20 is moved from an original position to at least a fluid pressure supply position. The first damper member 42 is energized to the side of the spool 20 by means of a spring 46. A fluid passage is formed on the first damper member 42 for communicating inside with outside of the damper chamber, while a check valve 50 is arranged on the way of the fluid passage for allowing only the flow in the direction into the damper chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot type directional control valve used for drive control of hydraulic winches.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional directional control valve.

The illustrated direction switching control valve 10 is a three-position fluid pressure (hydraulic pressure) pilot switching valve, and is used for drive control of a hydraulic motor of a winch for raising and lowering a hanging hook in this example. Pilot ports 12A and 12B are provided at both ends of the direction switching control valve 10, and a variable pressure reducing valve 16A and a variable pressure reducing valve 16B of the remote control valve 14 are connected to the pilot ports 12A and 12B, respectively.

The remote control valve 14 is configured to supply a pilot pressure proportional to the operation amount to the pilot port 12A (or 12B) on the side corresponding to the operation direction of the operation lever (not shown). In the example, when the operation lever is operated to the winding side, the pilot pressure proportional to the operation amount is supplied from the variable pressure reducing valve 16A to the pilot port 12A, and the operation lever is operated to the winding side. The pilot pressure proportional to the manipulated variable is supplied from the variable pressure reducing valve 16B to the pilot port 12
It is designed to be supplied to B.

The directional control valve 10 includes a central main block 18 and pilot blocks 1 on both left and right sides thereof.
9A and 19B, and accommodates therein a spool 20 extending in the left-right direction so as to be movable in the axial direction. On the left wing of the main block 18, there are P ports 22A and T.
A port 24A, a P port 22B and a T port 24B are formed in the right wing part, and a P port 26 for freed-off control is formed in the center part. Each of the P ports 22A, 22B, 2
6 is connected to a fluid pressure pump (not shown), and each T port 24
A and 24B are connected to a tank (not shown). Further, an A port 28A for fluid pressure output is provided between the P port 22A and the T port 24A, and a P port 22B and a T port 2 are provided.
B port 28B for fluid pressure output is formed between 4B and 4B, respectively.

On the other hand, small-diameter spool rods 30A are formed at predetermined positions on the left and right of the spool 20. A pin 32 is fixed to an end portion (left end portion in the drawing) of the spool 20 facing the pilot block 19A on the lowering side, and a spring seat 33 is attached to a head portion 32a of the pin 32 and an end portion of the spool 20. Spring seats 34 are fitted in the respective parts, and a spring 36 is interposed between both spring seats 33, 34 in a compressed state. Due to the elastic force of the spring 36, the spring seat 33 is moved to the pilot block 1
The spring seat 34 is held at a position where it abuts against the end face of the main block 18 at a step portion 38 formed in the vicinity of the pilot port 12A within 9A, whereby the spool rod 30A of the spool 20 is retained. The spool rod 30B is held at a neutral position (origin position; position shown) facing only the A port 28A and only facing the B port 28B.

Next, the operation of the directional control valve 10 will be described.

First, in the neutral state where the pilot pressure is not supplied, the spool rods 30A and 30B of the spool 20 have the A port 2 due to the elastic force of the spring 36.
8A and B port 28B, respectively, are held in the illustrated neutral position.

From this state, when the operation lever (not shown) is operated to the lowering side, for example, pilot pressure proportional to the operation amount is introduced into the pilot port 12A through the variable pressure reducing valve 16A of the remote control valve 14, and this pilot is operated. Upon receiving the pressure, the spring seat 33, the pin 32, and the spool 20 move integrally to the right in the drawing. Then, from the time when the spool rod 30A straddles the A port 28A and the T port 24A and the spool rod 30B straddles the B port 28B and the P port 22B, the fluid pressure pump discharges at a flow rate corresponding to the opening area. Fluid is P port 2
2B is supplied to one port of a fluid pressure motor (not shown) through the B port 28B, and the return fluid from the other port is released from the A port 28A to the tank (not shown) through the T port 24A. The pressure motor is driven in the lowering direction.

After that, when the operating lever is returned to the neutral position and the pilot pressure supply is stopped, the spool 20 is immediately returned to the neutral position by the elastic force of the spring 36.

[0011]

The above-mentioned directional control valve 1
At 0, when the spool 20 operates rapidly due to the introduction of pilot pressure, the spool rod 30A (or 30
When B) opens to the P port 22A (or 22B), the fluid pressure is suddenly supplied to the A port 28A (or B port 28B), and the shock is great. In particular, the shock at the time of lowering and switching (when fluid pressure is guided to the B port 28B in the illustrated example) cannot be ignored, and its mitigation becomes a major problem.

In order to avoid the shock, the driver may operate the operation lever extremely slowly, but it is difficult to request the driver to perform such an operation, and the burden is increased. Further, it is effective to provide a damper on the direction switching control valve 10 to regulate the stroke speed of the spool 10. However, by simply installing such a damper,
Since the speed at which the spool 20 returns from the fluid pressure supply position to the neutral position is regulated, there is a new inconvenience in that the fluid pressure supply cannot be immediately stopped.

Although the directional switching control valve 10 which is a three-position switching valve is shown in FIG. 6, the above-mentioned inconvenience is caused by having a unidirectional fluid pressure supply position and a block position (origin position).
The same applies to the position switching valve.

In view of such circumstances, the present invention reduces the shock at the time of switching from the origin position to the fluid pressure supply position, while at the same time ensuring a quick return to the origin position. The purpose is to provide.

[0015]

As means for solving the above problems, the present invention is directed to a fluid pressure supply position for guiding a fluid pressure introduced into a fluid pressure inlet port to a fluid pressure outlet port and an origin position other than that. And a holding means for holding the spool at the origin position, and moves the spool from the origin position to the fluid pressure supply position against the holding force of the holding means. In a directional control valve provided with a pilot supply passage for introducing a pilot pressure to be applied, at least a position where the spool comes into contact with a spool end opposite to the pilot port by the time the spool reaches the fluid pressure supply position. A first damper member that is provided and moves together with the spool in a direction from the origin position to the fluid pressure supply position in a state of being in contact with the spool end portion; The first damper member is fitted with the second damper member, and the first damper member forms a damper chamber whose volume changes with the movement of the first damper member. An urging means for urging in a direction from the supply position to the origin position, and at least one of the first damper member and the second damper member is formed with a throttle portion that communicates the inside and outside of the damper chamber, and The first damper member is provided with a fluid introduction passage that has a larger flow passage area than the throttle portion and communicates the inside and the outside of the damper chamber, and the fluid is introduced only in the direction from the outside to the inside of the damper chamber in the middle of the fluid introduction passage. It is provided with a direction regulating means for allowing the flow (Claim 1).

It is more preferable that the maximum inner diameter of the damper chamber is smaller than the maximum outer diameter of the spool.

The arrangement position of the first damper member is as follows.
It is more preferable that a position such that a gap having a size smaller than the stroke from the origin position to the fluid pressure supply position is formed between the spool end held at the origin position and the first damper member (claim) Item 3).

Further, the side walls of the first damper member and the second damper member are provided with communicating portions for communicating the inside and outside of each side wall, and the spool contacting the first damper member reaches the fluid pressure supply position. By setting the positions of both the communication parts so that the two communication parts face each other after moving further by a predetermined distance after that, a more excellent effect as described later can be obtained (claim 4).

A second fluid pressure different from the fluid pressure outlet port is applied to the fluid pressure inlet port at a position opposite to the fluid pressure supply position across the spool from the origin position. The spool is configured to be movable between a second fluid pressure supply position guided to the outlet port and the origin position, and this spool moves from the origin position to the second fluid pressure supply position against the holding force of the holding means. A second pilot supply passage may be provided for introducing a pilot pressure that operates in the direction (claim 5).

[0020]

In the control valve, when pilot pressure is supplied from the pilot supply passage, the spool moves from the neutral position to the fluid pressure supply position against the holding force of the holding means. At this time, the end of the spool contacts the first damper member at least until the spool reaches the fluid pressure supply position, and the first damper member also moves in the same direction as the spool. The first damper member moves in the above-mentioned direction while reducing the volume inside the damper chamber, but in the fluid introduction path communicating between the inside and outside of the damper chamber, the action of the direction regulating means prevents the outflow of the fluid, so that the volume of the damper chamber is reduced. The flow rate of the fluid outflow in the damper chamber due to the decrease is regulated by the throttle. For this reason, the stroke speeds of the first damper member and the spool are also regulated, and the spool reaches the fluid pressure supply position at a low speed, thereby relaxing the shock at the time of switching the fluid pressure supply.

In this fluid pressure supply state, the spool and the first damper member are in contact with each other, but since the two are separate members, when the supply of the pilot pressure is stopped, the spool is held by the holding force of the holding means. Immediately returns from the first damper member to the neutral position. Further, since the fluid inflow from the outside to the inside of the damper chamber is allowed in the fluid introduction passage, the volume of the damper chamber is increased along with this inflow, and the first damper member is relatively urged by the urging force of the urging means. Follows the return of the spool quickly. Therefore, even if the pilot pressure supply is restarted relatively early after the pilot pressure is stopped, the stroke speed reducing action by the damper chamber can be obtained as in the previous case.

In this control valve, the smaller the maximum inner diameter of the damper chamber, the larger the force required to return the first damper member to the original position while increasing the volume of the damper chamber (that is, the urging means. (Urging force) can be reduced. Further, the larger the maximum outer diameter of the spool on the pilot port side (that is, the larger the pressure receiving area thereof), the larger the total operating force that the pilot pressure gives to the spool. Therefore, when the maximum inner diameter of the damper chamber is set to be smaller than the maximum outer diameter of the spool as in the control valve according to the second aspect, the biasing force of the biasing means affects the spool stroke by the pilot pressure. Can be smaller.

Further, in the control valve according to the third aspect, a gap smaller than the stroke from the neutral position to the fluid pressure supply position is provided between the spool end held at the neutral position and the first damper member. Since it is formed, the spool does not come into contact with the first damper member until the spool moves from the neutral position by the above-mentioned gap, and therefore operates quickly as in the conventional control valve. After the spool comes into contact with the first damper member, the stroke speed of the spool is reduced by the action of the damper chamber as described above.
After that, the spool reaches the fluid pressure supply position at a low speed.

Further, in the control valve of the fourth aspect, the first damper member and the second damper member are provided after the spool reaches the fluid pressure supply position in a state where the first damper member is in contact with the spool end portion. The communicating portions provided on the member start to face each other. From this point onward, the fluid in the damper chamber also flows to the outside through both the communicating portions, so that the stroke speed of the spool increases again.

Further, in the control valve according to the fifth aspect, the spool is moved from the neutral position to the second fluid pressure supply position opposite to the fluid pressure supply position by the pilot pressure supply from the second pilot supply passage. Thereby, the fluid pressure is guided to the second fluid pressure outlet port different from the fluid pressure outlet port.
That is, the control valve acts as a switching valve having at least three positions. Moreover, since the spool end portion is separated from the first damper member at the neutral position and the pilot pressure introduced from the second pilot supply passage acts on the entire end portion, the pilot pressure does not have to be particularly high. Also, the spool can be operated to the second fluid pressure supply position side with sufficient force.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, the remote control valve 14, the main block 18 of the direction switching control valve 10, the spool 20,
The internal structure of the pilot block 19A on the lowering side is the same as that shown in FIG. 6, and the description thereof is omitted here.

In this embodiment, as a feature of the direction switching control valve 10, a stroke speed control device 40 for controlling the stroke speed of the spool 20 is provided inside the winding side pilot block 19B. The stroke speed control device 40 includes a first damper member 42, a second damper member 44, and a spring 46.

As shown in FIG. 2, the first damper member 4 is provided.
2 has a bush portion 42a, a main body portion 42b, and a cylindrical piston portion 42c in this order from the side closer to the spool 20. The bush portion 42a has a maximum outer diameter of the spool 20 (outer diameter of portions other than the spool rods 30A and 30B;
Hereinafter, this is simply referred to as the spool diameter. ) D has a cylindrical shape having an inner diameter slightly larger than D, and the end portion of the spool 20 is fitted in the bush portion 42a. Body 42b
Is integrally formed with the bush portion 42a and has an outer diameter smaller than the spool diameter D. The cylindrical piston portion 42c has an outer diameter equal to that of the main body portion 42b, and is connected to the main body portion 42b.

On the other hand, the second damper member 44 integrally has a cylinder portion 44a and a collar portion 44b in order from the side closer to the spool 20. The cylinder portion 44a is
The cylindrical piston portion 42c and the main body portion 42b of the first damper member 42 have inner diameters into which the cylindrical piston portion 42c and the main body portion 42b are fitted with each other with almost no gap, and the first damper member 42 forms a variable volume damper chamber 56. Therefore, the maximum inner diameter of the damper chamber 56 (that is, the inner diameter of the cylinder portion 44a; hereinafter simply referred to as the damper chamber diameter) d is smaller than the spool diameter D. Further, the flange portion 4 is provided on the side wall of the cylinder portion 44a.
The portion close to 4b penetrates the side wall of the cylinder portion (that is, communicates the inside and outside thereof) with a small area 58.
Has been drilled.

The collar portion 44b is the cylinder portion 44a.
The second damper member 44 has a larger outer diameter and hits the step portion 47 at the peripheral edge of the hoisting side pilot port 12B to prevent the second damper member 44 from moving toward the pilot port 12B side. A groove 44c that connects the hoisting side pilot port 12B and the chamber around the cylinder portion 44a is formed in the collar portion 44b. And this collar part 44
The spring (biasing means) 46 is interposed in a compressed state between b and the bush portion 42a, and the elastic force of the spring 46 causes the first damper member 42 to approach the spool 20 (see FIG. No. 1 and 2 are urged to the left). Here, the disposition position of the first damper member 42 is from the neutral position to the fluid pressure supply position between the end surface of the spool 20 and the bottom surface of the bush portion 42a with the spool 20 in the neutral position. Is set so as to secure a gap (FIG. 2) having a dimension δ smaller than the stroke so (FIG. 1).

Further, the bush portion 42a is formed with a through hole 42d which communicates the inside of the bush portion 42a with the storage chamber of the spring 46. The through hole 42d, the groove 44c, and the pilot port 12B form a through hole 42d. A pilot supply path (second pilot supply path in the present invention) that guides the hoisting pilot pressure to the spool 20 is configured.

Further, a fluid passage 42e is formed in the main body portion 42b so that the inside of the cylindrical piston portion 42c, the storage chamber of the spring 46 and the inside of the bush portion 42a communicate with each other. A portion of the fluid passage 42e that faces the inside of the cylindrical piston portion 42c is a valve chamber 49 having a larger inner diameter than other portions, and a plug 48 having an axial through hole 48a is formed so as to close the valve chamber 49. The through hole 48a of the plug 48 and the fluid passage 42e are attached to form a fluid introduction passage that communicates the inside and outside of the damper chamber 56.

A ball 52 and a spring 54 are housed in the valve chamber 49 in order from the side closer to the spool 20.
As a result, the check valve (direction regulating means) 50 is formed. The spring 54 includes the ball 52 and the flag 4 described above.
8 is interposed in a compressed state with the spring 5
The ball 52 is pressed against the tapered valve seat surface 42f formed in the valve chamber 49 by the elastic force of 4.
Sealing is performed at this contact portion. Therefore, the check valve 50 allows the fluid to flow from the outside to the inside of the damper chamber 56 by the elastic force of the spring 54, while preventing the fluid from flowing from the inside to the outside of the damper chamber 56. .

Next, the operation of the directional control valve 10 will be described.

First, in the neutral state where the pilot pressure is not supplied, the spool 20 is elastically urged by the spring 36 so that the spool rods 30A and 30B shown in FIG. 1 face the A port 28A and the B port 28B respectively. Held in. In this state, both ports 28A, 2
8B is cut off from the hydraulic pump and the tank.

Next, when the operation lever (not shown) is operated, for example, to the lowering side, pilot pressure proportional to the operation amount is introduced into the pilot port 12A through the variable pressure reducing valve 16A of the remote control valve 14, and this pilot pressure is supplied. In response to this, the spring seat 33, the pin 32, and the spool 20 integrally move to the right in the drawing. And spool rod 3
0A crosses the A port 28A and the T port 24A, and the spool rod 30B crosses the B port 28B and the P port 22B, that is, the spool 20 shown in FIG.
From the time point of moving by the stroke so shown in Fig. 10, the discharge fluid of the fluid pressure pump is supplied from the P port 22B to the one port of the fluid pressure motor (not shown) through the B port 28B at a flow rate according to the opening area, and the other port. The return fluid from is released to the tank (not shown) from the A port 28A through the T port 24A, whereby the fluid pressure motor is driven in the lowering direction.

On the other hand, in the stroke speed control device 40, since the spool 20 is separated from the first damper member 42 from the start of the operation of the spool 20 to the movement of the dimension δ, the stroke speed There is no regulation, so the spool 20 operates independently and quickly as before. On the other hand, from the time when the spool 20 contacts the first damper member 42 (the time before reaching the fluid pressure supply position), the spool 20 and the first damper member 42 move to the second damper member 44. Move together towards.
In order for the first damper member 42 to move in this direction, it is necessary to reduce the volume of the damper chamber 56 while pushing out the fluid in the damper chamber 56, but the check valve 50 acts to pass through the through hole 48a and the fluid passage 42e. Since the outflow of the fluid is blocked, most of the fluid in the damper chamber 56 flows out to the outside only from the throttle portion 58. Here, the diaphragm unit 5
Since the flow passage area of 8 is minute and the outflow rate is reduced accordingly, the moving speeds of the spool 20 and the first damper member 42 are remarkably reduced (see FIG. 3).

Therefore, after the spool 20 and the first damper member 42 come into contact with each other, the spool 20 reaches the fluid pressure supply position at a low speed, so that the shock at the start of the fluid pressure supply is greatly reduced. It

After that, when the operation lever is returned to the neutral position and the supply of the pilot pressure is stopped, the spool 20 is also separated from the first damper member 42 by the elastic force of the spring 36 and immediately returns to the neutral position. That is, by returning the operation lever to the neutral position, the fluid pressure supply can be quickly stopped without causing a significant operation delay. Moreover, since the check valve 50 allows the fluid to flow from the outside to the inside of the damper chamber 56, the first damper member 42 also increases the elastic force of the spring 46 while increasing the volume of the damper chamber 56 with this inflow. Moves relatively quickly to the original position (that is, to the left in FIGS. 1 and 2). Therefore, even if the operating lever is re-operated to the lowering side (that is, the pilot pressure supply is restarted) at a relatively early time after the return of the spool 20 to the neutral position, the spool 20 and the first spool can be operated at substantially the same time as described above. The damper member 44 can be brought into contact with the damper member 44, and the same stroke speed reducing action as described above can be obtained again.

Further, when the operating lever is operated to the winding side from the neutral position, the pilot pressure output from the variable pressure reducing valve 16B is applied to the pilot port 12B and the groove 44.
c and through the through hole 42d, the spool 20 is directly supplied to the spring seat 34.
Along with pressing the spring 36, it moves to the left side in FIG. The spool rod 30A is connected to the P port 2
2A and A port 28A, and spool rod 30B straddles T port 24B and B port 28B, so that A port 28A is connected to the fluid pressure pump and B port 28B is connected to the tank. The motor is driven on the winding side.

As described above, according to the directional control valve 10, the shock generated during the operation on the lowering side is effectively alleviated, while the return from the lowering position to the neutral position can be performed quickly. Further, even when the operation is performed again in the unwinding direction from the neutral state, the shock mitigating effect equivalent to the previous time can be obtained.

Further, in the neutral state, a gap is secured between the spool 20 and the first damper member 44, and a large stroke speed is secured in a period before the spool 20 reaches the lowering drive position. Therefore, it is possible to maximize the switching responsiveness while reducing the shock at the time of lowering and switching.

The smaller the diameter d of the damper chamber, the smaller the elastic force of the spring 46 for returning the first damper member 42 to the original position while increasing the volume of the damper chamber 56. The larger the diameter D (that is, the larger the pressure receiving area), the larger the total operating force of the pilot pressure applied to the spool. Here, in the directional control valve 10, the damper chamber diameter d is larger than the spool diameter D. Since it is also set small, the above spring 4
It is possible to further reduce the influence of 6 on the spool stroke due to the pilot pressure, and it is possible to ensure good spool operation despite the presence of the spring 46.

The second embodiment is shown in FIG. In this embodiment, the side wall of the cylindrical piston portion 42c shown in the first embodiment is provided with the narrowed portion 60 having a minute flow passage area that penetrates the side wall, and the inner peripheral surface of the side wall of the cylinder portion 44a is in a neutral state. A peripheral groove 62 is formed at a position separated from the narrowed portion 60 by a distance s, and a through hole 64 that connects the peripheral groove 62 and the outside of the cylinder portion 44c is formed. Here, the distance s is set such that the sum (δ + s) of the distance s and the gap size δ is larger than the stroke so from the neutral position to the lowering drive position.

According to such a structure, when the spool 20 reaches the lowering drive position and further moves by a predetermined dimension (specifically, it moves by a distance (δ + s) from the neutral position), the throttle portion 60 moves around the circumference. By facing the groove 62, the fluid in the damper chamber 56 can also flow out through the throttle portion 60 and the through hole 64. The damper room 56
As a result, the speed regulation due to is decreased, and the spool operating speed is increased again as shown in FIG.

Therefore, according to this embodiment, the spool operating speed can be reduced to reduce the shock at the time of switching the winding operation, and a high spool operating speed can be secured both before and after the shock.

The present invention is not limited to the above embodiments, but the following modes can be adopted as examples.

(1) In the above embodiment, the directional switching control valve 10 for switching three positions is shown. However, the present invention is a two position switchable to a unidirectional fluid pressure supply position and a block position (origin position). It can also be applied to a switching valve. In this case, in the directional control valve 10 shown in FIG. 1, the pilot port 12B may be a drain port, for example. Further, when it is used as a three-position switching valve, it is not limited to the one used for the winch drive control as described above, but can be widely applied when it is necessary to mitigate the shock when switching to one direction. .

(2) In the first embodiment, the gap dimension δ
Is set to 0, that is, even if the end portion of the spool 20 and the first damper member 44 are kept in contact with each other in the neutral state,
It is possible to secure a shock reduction at the time of lowering and a quick return to the neutral position.

(3) In each of the above embodiments, the bush portion 4
The stroke 2a can be omitted, and at least the stroke speed reducing effect can be obtained as long as the first damper member 44 and the spool 20 contact each other before the spool 20 reaches the fluid pressure supply position.

(4) In the above embodiment, the first damper member 42
Although the piston part and the cylinder part are provided on the second damper member 44 to form the damper chamber, the cylinder part is provided on the first damper member 42 and the piston part is provided on the second damper member 44. It is also possible to form a damper chamber.

(5) In the first embodiment described above, the A port 28A and the B port 28B are blocked at the neutral position. However, at the neutral position, both ports 28A and 28B are connected to both the fluid pressure pump and the tank, respectively. To communicate with
The present invention is also applicable to a device that connects both ports 28A and 28B.

(6) In the second embodiment, a through hole having a normal area is provided on the side of the cylindrical piston portion 42c, and the cylinder portion 4
A narrowed portion may be provided on the side of 4a, or normal through holes may be provided on both sides.

[0054]

As described above, according to the present invention, the first damper member and the second damper member form a damper chamber for speed regulation,
Since the spool comes into contact with the first damper member and moves together with the first damper member at least before reaching the fluid pressure supply position, the spool speed at the time of reaching the fluid pressure supply position is By reducing this, the shock at the time of position switching is mitigated, while the return from the fluid pressure supply position of the spool to the home position is performed quickly, so that the responsiveness at the time of switching to the home position is the same as before. There is an effect that it can be secured well. Moreover, a direction regulating means for urging the first damper member in the direction toward the spool and providing a fluid introduction path communicating between the inside and outside of the damper chamber, and allowing the flow of the fluid only in the direction toward the damper chamber in the fluid introduction path. Since the spool is returned to the original position, the first damper member can be returned to the original position (that is, brought closer to the spool) at a relatively high speed following the return to the original position. Even if the pilot pressure is re-supplied at a relatively early stage after returning to the position, the same stroke speed reduction effect as the previous time can be obtained.

In the control valve according to the second aspect of the present invention, the maximum inner diameter of the damper chamber is set smaller than the maximum outer diameter of the spool, so that the urging force of the urging means can be kept low while the pilot pressure is reduced. By maintaining a large total pressure for operating the spool, the effect of the biasing force on the spool stroke by the pilot pressure can be reduced.

Further, in the control valve of the third aspect, a gap smaller than the stroke from the origin position to the fluid pressure supply position is provided between the spool end held at the origin position and the first damper member. Since it is formed, by maintaining a high spool operating speed for a predetermined period before the spool reaches the fluid pressure supply position, it is possible to obtain a high switching responsiveness while securing a shock absorbing effect at the time of switching. There is.

Further, in the control valve according to the fourth aspect, after the spool reaches the fluid pressure supply position, the communicating portions provided on the first damper member and the second damper member are made to face each other so that the communicating portions are opposed to each other. Also, since the fluid in the damper chamber is made to flow to the outside, a high spool operating speed can be obtained both before and after switching to the fluid pressure supply position, and there is an effect that responsiveness can be further enhanced.

Further, in the control valve according to the fifth aspect, the spool is moved from the origin position to the second fluid pressure supply position opposite to the fluid pressure supply position by the pilot pressure supply from the second pilot supply passage. The second fluid pressure outlet port different from the above fluid pressure outlet port is communicated with the fluid pressure inlet port, so that at least three control valves are provided.
It can be used as a position switching valve. Moreover, as described above, the spool end portion is separated from the first damper member at the origin position, and the pilot pressure introduced from the second pilot supply passage acts on the entire end portion. There is an effect that the spool can be operated to the second fluid pressure supply position side with a sufficient force without setting it high.

[Brief description of drawings]

FIG. 1 is a sectional view of a directional control valve according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a main part of the directional control valve.

FIG. 3 is a graph showing a change in spool stroke speed in the directional control valve.

FIG. 4 is a sectional view showing a main part of a directional control valve according to a second embodiment.

FIG. 5 is a graph showing a change in spool stroke speed in the directional control valve.

FIG. 6 is a sectional view showing an example of a conventional directional control valve.

[Explanation of symbols]

10 Directional Control Valve 12A Pilot Port (Pilot Supply Channel) 12B Pilot Port (Second Pilot Supply Channel) 22A, 24A P Port (Fluid Pressure Inlet Port) 28A A Port (Fluid Pressure Outlet Port) 28B B Port (No. 2 fluid pressure outlet port) 36 spring (holding means) 40 stroke speed control device 42 first damper member 42d through hole (constituting second pilot supply passage) 44 second damper member 44c groove (constituting second pilot supply passage) 46 spring (biasing means) 50 check valve (direction regulating means) 56 damper chamber 58 throttle portion 60 throttle portion (communication portion) 64 through hole (communication portion) δ gap size between spool end portion and first damper member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F16K 31/12 7214-3H

Claims (5)

[Claims] 1. A spool that moves in the axial direction between a fluid pressure supply position that guides the fluid pressure introduced to the fluid pressure inlet port to the fluid pressure outlet port and an origin position other than that, and a spool that moves the spool to the origin position. And a holding means for holding the spool, and a direction switching control provided with a pilot supply passage for introducing a pilot pressure for moving the spool from the origin position to the fluid pressure supply position against the holding force of the holding means. The valve is provided at a position where it abuts on the spool end opposite to the pilot port at least by the time the spool reaches the fluid pressure supply position. From the first to the fluid pressure supply position, and a first damper member that is fitted to the first damper member, A second damper member that forms a damper chamber whose volume changes with the movement of the first damper member;
Urging means for urging the damper member in the direction from the fluid pressure supply position to the origin position, and a throttle unit that communicates the inside and outside of the damper chamber with at least one of the first damper member and the second damper member. And the first
The damper member is provided with a fluid introduction passage that has a larger flow passage area than the throttle portion and communicates the inside and outside of the damper chamber, and a fluid flow is provided only in the direction from the outside to the inside of the damper chamber in the middle of the fluid introduction passage. A directional control valve, which is provided with a directional control means that allows it. 2. The directional control valve according to claim 1, wherein the maximum inner diameter of the damper chamber is set to be smaller than the maximum outer diameter of the spool. 3. The directional control valve according to claim 1, wherein the stroke from the origin position to the fluid pressure supply position is between the spool end held at the origin position and the first damper member. A directional control valve, wherein the disposition position of the first damper member is set so that a clearance having a small size is formed. 4. The directional control valve according to claim 3, wherein the side walls of the first damper member and the second damper member are provided with communication portions that communicate the inside and outside of each side wall, and contact the first damper member. The directional control valve is characterized in that the positions of the two communication parts are set so that the two communication parts face each other when the spool further moves a predetermined distance after reaching the fluid pressure supply position. 5. The directional control valve according to claim 3 or 4, wherein the spool is a fluid that is introduced into the fluid pressure inlet port at a position opposite to the fluid pressure supply position across the origin position. It is configured to be movable between a second fluid pressure supply position that guides pressure to a second fluid pressure outlet port different from the fluid pressure outlet port and the origin position, and this spool resists the holding force of the holding means. From the origin position to the second
A directional control valve comprising a second pilot supply passage for introducing a pilot pressure for operating in a direction toward a fluid pressure supply position.