JPS63145804A - Pilot operated type opening and closing valve - Google Patents

Abstract

PURPOSE:To make secure shutting-off between an inflowing port and an outflowing port by controlling the pilot liquid discharge, which is for actuating a poppet valve unit to open and close, by means of a pilot operated type valve unit composed of a poppet valve portion. CONSTITUTION:An inflowing port A2 and an outflowing port A1 are of a constitution so that the connection between the two ports shall be shutoff by a poppet valve unit 24. The pilot liquid discharge, which is for actuating the poppet valve unit 24 to open and close, is controlled by a pilot operated type valve unit 49 composed of a poppet valve portion 50. This method makes it possible to control a large volume of pressure liquid with a small volume of pilot liquid and, furthermore, it enables the poppet valve unit 24 to make secure shutting-off between the inflowing port A2 and the outflowing port A1 because there is not leak of the pilot liquid if the poppet valve portion 50 closes.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a pilot-operated on-off valve,
In particular, it relates to a pilot-operated on-off valve that has both a counterbalance function that prevents the piston from advancing rapidly when the cylinder load suddenly decreases, and a locking function that prevents the piston from falling under its own weight.

(Prior Art) Fig. 3 shows a conventional self-weight drop prevention circuit using a pilot check valve and an external pilot type counterbalance valve. In Fig. 3, 1 is a hydraulic source, 2 is a tank, 3 is an electromagnetic directional valve, 4 is a hydraulic cylinder that is supplied with pressure oil from the hydraulic source 1 by switching the directional valve 3, and 5 is a hydraulic cylinder. The acting load 6 is a conduit connecting the rod chamber of the hydraulic cylinder 4 and the directional control valve 3, and the conduit 6 includes a pilot check valve 7 and a well-known counterbalance valve 9 with a built-in check valve 8. is provided. 10 is a pipe connecting the head chamber of the hydraulic cylinder 4 and the directional control valve 3; 11 is a pilot pipe connecting the pilot boat of the pilot check valve 7 and the pipe 10; 12 is a pilot port of the counterbalance valve 9. This is a pilot pipe line that connects the pipe line 10 and the pipe line 10.

In this hydraulic circuit, when the directional control valve 3 is switched to the A position, pressure oil is supplied to the rod chamber of the hydraulic sill 4 through the check valve 8 and the pilot check valve 7, and the load 5 increases. When the directional control valve 3 is in the neutral position shown, the pilot check valve 7 shuts off the pipe line 6, so the hydraulic cylinder 4 is locked. When the directional control valve 3 is switched to the B position, pressure oil is supplied to the head chamber of the hydraulic cylinder 4 through the line 10, and at this time, the pressure oil in the line 10 passes through the pilot line 11 and the pilot line 12 to the pilot check. It acts on the valve 7 and the counterbalance valve 9, and each valve 7,
Open 9. As a result, the rod chamber of the hydraulic sill 4 and the tank 2 are communicated with each other, and the load 5 is lowered. At this time, the pressure oil flowing out from the hydraulic cylinder 4 gradually flows out from the valve outlet while going against the set pressure of the counterbalance valve 9, so that even if the load suddenly decreases, the piston will not move rapidly.

(Problems to be Solved by the Invention) Since the counterbalance valve 9 and the directional control valve 3 used in the conventional self-weight drop prevention circuit described above are composed of spool valves, the sliding contact surface between the spool valve and the body hole There is a small amount of oil leaking, so even if the directional control valve 3 is switched to the neutral position, the piston moves down little by little. In order to prevent this and reliably lock the piston position, the pilot check valve 7 is essential.

By the way, the pilot pressure that enables backflow of the pilot check valve generally requires a pressure that is 40% or more of the outlet side pressure, but in the hydraulic circuit with the above configuration, even if the pressure in the pipe line 10 is constant, the hydraulic sill 4 used Since the pressure of the oil in the rod chamber is increased depending on the ratio of the rod-side pressure-receiving area to the head-side pressure-receiving area, the pressure in the pipe line 6 differs. Therefore, in order to open the pilot check valve 7 with the pilot pressure led from the pipe line 10, the ratio of the seat diameter of the pilot check valve 7 and the pilot piston diameter must be changed according to the ratio of the pressure receiving area on the rod side and the pressure receiving area on the head side. The ratio between the pressure on the outlet side A2 of the check valve 7 and the pilot pressure required to open the pilot check valve 7 must be adjusted as appropriate.

In addition, the pressure on the outlet side A2 changes depending on the magnitude of the load 5, and accordingly the pressure in the pipe line 10 required to open the pilot check valve 7 also changes greatly, which causes cylinder shock and increases vibration and noise. There was a risk that this would occur.

(Means for Solving the Problems) In view of the above problem α, the present invention provides a pilot-operated on-off valve that can lock the position of the piston without providing a special pilot check valve and that can prevent the piston from advancing rapidly. The purpose is to provide the following.

The structure of the present invention that meets this purpose is that the inflow hole A2 and the outflow hole A
1, and a first pilot flow that guides the pilot liquid to the action chamber 3J formed at the back of the poppet valve body 24. F33, the crest 32 interposed in the first pilot flow path 33, the return spring 27 that is engaged with one end of the poppet valve body 24 and biases the poppet valve body in the closing direction, and the action chamber 31. a first communication passage 34.41 connected to the working chamber 31 for discharging the pilot liquid;
A small-diameter sliding hole 43 connected to the communication passage 34, 41, a large-diameter hole 44 connected to the sliding hole 43, and a step formed in the connecting step between the large-diameter hole 44 and the sliding hole 43. Valve seat 48 and large diameter hole 4
4, and the valve seat 48 at one end.
A poppet valve portion 50 is formed at the other end of the poppet valve portion 50 to detach from the slide hole 43 to block communication between the slide hole 43 and the large diameter hole 44, and a slide portion 53 is formed at the other end to slidably fit into the slide hole 43. The valve portion 50 and the sliding portion 53 are connected by a connecting shaft portion 54 to form the first communication path 3.
A valve body 49 on which a hydraulic pressure of 4°41 acts in equilibrium, and the valve body 49
A return spring 58 that is engaged with and urges the poppet valve portion 50 to seat on the valve seat 48, and a return spring 58 that is engaged with the valve portion 50 and urges the poppet valve portion 50 to seat on the valve seat 48; 2 pilot flow paths 60.

(Function) According to the above configuration, when there is no pilot liquid in the second pilot flow path 60 with a pressure that overcomes the biasing force of the return spring 58, the return spring 58 causes the poppet valve portion 50 to move toward the valve seat 48.
The sliding hole 43 and the large-diameter hole 44 are shut off, and the first communication path 34, 41 and the second communication path 45 connected to the sliding hole 43 and the large-diameter hole 44 are also cut off. . Therefore, at this time, when the pilot liquid is introduced into the action chamber 31 through the first pilot flow path 33, the second pilot fluid is not discharged from the action chamber 31, but acts on the back of the poppet valve body 24, and the second pilot fluid acts on the back of the poppet valve body 24. The body 24 blocks the darkness of the inflow hole A2 and the outflow hole A1. At that time, the first pilot flow path 33
The action chamber 3 is provided with resistance by interposing the ridge 32
The pilot liquid of No. 1 does not leak out from the first pilot flow path 33. Pilot pressure is also applied to the valve body 49 through the first communication passage 34.41;
9, the poppet valve portion 50 will not open due to this pilot pressure.

On the other hand, when a pilot liquid at a predetermined pressure is introduced into the second pilot flow path 60 and acts on the valve body 49, the poppet valve portion 5 resists the return spring 58 due to this pilot pressure.
0 is removed from the valve seat 48, and the first communication passage 34.41 and the second
The communication paths 45 communicate with each other. As a result, the pilot liquid in the action chamber 31 is transferred from the first communication path 34.41 to the second communication path 4.
When the pressure liquid acts on the inflow hole A2, the poppet valve body 24 opens due to the pressure, and the inflow hole A2 and the outflow hole A1 communicate with each other.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. The main valve body 20 has an inflow hole A2, an outflow hole A1, and these inflow hole A2 and outflow hole A1.
An annular groove 21 communicating with the annular groove 21 and a sliding hole 22 connected to the annular groove 21 are provided. A valve seat 23 having a diameter smaller than the inner diameter of the sliding hole 22 is formed at the step where the inflow hole A2 and the annular groove 21 are connected. On the other hand, a poppet valve body 24 is slidably fitted into the sliding hole 22, and is seated on a valve seat 23 at the left end of the poppet valve body 24 to block the flow between the inflow hole A2 and the outflow hole 1. A truncated conical portion 25 is formed, and a hole 26 is bored at the right end for the return spring receiver.

A return spring 27 is attached to the hole 26 of the return spring receiver, and urges the poppet valve body 24 in a direction to seat the truncated conical portion 25 on the valve seat 23. Reference numeral 28 denotes an O ring wrapped around the poppet valve body 24 to prevent liquid leakage from the sliding contact surface between the poppet valve body 24 and the sliding hole 22. The sliding hole 22
A plug 29 is fitted to the rear end of the poppet valve body 24, and an action chamber 31 is provided on the back of the poppet valve body 24. 30 is an O-ring wrapped around the plug 29 to prevent liquid leakage from the joint surface between the sliding hole 22 and the plug 29. Furthermore, the main valve body 2
0, a first pilot flow path 33 communicating with the action chamber 31 and having a ridge 32 interposed in the intermediate portion is bored. Further, the plug 30 is also provided with a passage 34 that communicates with the action chamber 31 .

Next, 40 is an auxiliary valve body, and the auxiliary valve body 40 is connected to the main valve body 20 by fastening means (not shown) such as bolts.
are integrally fixed by. This auxiliary valve body 4
0 is provided with a flow path 41 connected to the flow path 34,
An O-ring 42 for preventing liquid leakage is provided at the connecting portion between the two. These passages 34 and 42 form a first communication passage for discharging the pilot liquid from the working chamber 31. Further, the auxiliary body 40 is provided with a small-diameter sliding hole 43 communicating with the flow path 41, a large-diameter hole 44 connected to the sliding hole 43, and a second communicating path 45 communicating with the large-diameter hole 44. has been done. The lower end surface of this large diameter hole 44 is closed by a plug 4.6 screwed onto the auxiliary body 40.

Reference numeral 47 denotes an O-ring for preventing liquid leakage, which is interposed between the joint surfaces of the large-diameter hole 44 and the plug 46. A valve seat 48 is formed in the gear stage portion of the sliding hole 43 and the large diameter hole 44, and the sliding hole 4
A valve body 49 is slidably fitted into the valve body 3 . Valve body 49
A poppet valve portion 50 and a return spring 58 are provided at the lower end of the valve seat 48 to heat the valve seat 48 and cut off communication between the sliding hole 43 and the large diameter hole 44.
A step portion 52 is formed for engaging the slider, and a sliding portion 53 is formed at the upper end to slidably fit into the sliding hole 43.
The poppet valve part 50 and the sliding part 53 are connected by a connecting shaft part 54. Reference numeral 55 denotes an O-ring wrapped around the sliding portion 53 to prevent liquid leakage from the sliding contact surfaces of the sliding hole 43 and the sliding portion 53. Since the diameter of the valve seat 48 and the diameter of the sliding portion 53 are set to be the same, the areas of the pressure receiving surface 56 of the poppet valve body 50 and the pressure receiving surface 57 of the sliding portion 53 on which the pilot liquid in the flow path 41 acts are equal. Therefore, the pilot pressure in the flow path 41 acts in equilibrium on the valve body 49, so that no matter how much the pilot pressure is, the poppet valve portion 50 is moved against the valve seat 49 by the pilot pressure.
There will be no departure from 8. A return spring 58 is engaged between the stepped portion 52 and the plug 46, and biases the poppet valve portion 50 to seat on the valve seat 48. Further, the auxiliary valve body 40 is formed with a pressurizing chamber 59 connected to the sliding hole 43 and a second pilot passage 60 communicating with the pressurizing chamber 59.

This embodiment has the above-mentioned configuration.Next, the operation when this embodiment is applied to a self-weight drop prevention circuit in place of the pilot check valve 7 and counterbalance valve 9 shown in FIG. 3 is shown in FIGS. This will be explained based on Figure 2.

First, connect the rond side of the hydraulic cylinder 4 and the inflow hole A2 to the pipe 7.
1. Conduit 72. The outflow hole A1 and the directional control valve 3 are connected by a pipe 74. It is connected by a conduit 75. Next, a pipe line 76 is interposed between the pipe line 72 and the pipe line 75, and a check valve 77 is provided in the pipe line to prevent free flow of the return oil from the rod side of the silling 4. Also hydraulic shilling 4
The head side of the directional control valve 3 is connected to the directional control valve 3 by a conduit 78. Further, a pilot pipe line 79 branched from the pipe line 71 is connected to the first pilot flow path 33. Further, the second pilot channel 60 is connected to a pilot channel 80 branched from the channel 78, and the second communicating path 45 and the channel 75 are connected by a channel 81.

In the hydraulic circuit configured as described above, when the directional control valve 3 is in the neutral position shown in FIG. Instead, the valve body 49 is urged upward by the return spring 58, the poppet valve portion 50 is seated on the valve seat 48, and the space between the large diameter hole 44 and the sliding hole 43 is cut off. On the other hand, the pressure oil in the rod chamber of the sill 4 pressurized by the load 5 flows from the pipe 71 to the pilot pipe 79. It passes through the first pilot flow path 33, flows into the action chamber 31, acts on the back of the poppet valve body 24, and flows from the pipe 71 to the pipe 72 and pipe 73 to the truncated conical part 25 of the poppet valve body 24. also works. However, since the pressure acting on the back of the poppet valve element and the biasing force of the return spring 27 exceed the pressure acting on the truncated cone part 25, the poppet valve element 24 moves to the left, and the truncated cone part 25 moves toward the valve seat 25.
MH the inflow hole A2 and the outflow hole A1.

As a result, pipe line 71, pipe line 72, pipe line 73, pipe line 74,
Since the flow path formed by the pipe line 75 is blocked, the pressure oil in the rod chamber of the cylinder 4 is not discharged to the tank 2, and the piston position of the cylinder 4 is locked. Meanwhile, since the first pilot flow path 33 is provided with a throttle 32 to provide resistance to the flow path, the pressure oil in the working chamber 31 will not leak through the first pilot flow path 33. Inflow hole A2
Since the outflow hole A1 is closed by the poppet valve body 21 which has an excellent sealing effect, it is possible to reliably prevent the load 5 from falling under its own weight due to oil leakage as seen in valves with a spool structure.

Similarly, since the poppet valve section 50 also blocks the darkness between the sliding hole 43 and the large diameter hole 44, there is a risk that the pilot liquid in the action chamber 31 will leak and the pilot pressure acting on the poppet valve body 24 will decrease. Nor. Moreover, the pilot pressure applied to the valve body 49 through the flow passage 34 and the flow passage 41 forming the first communication passage has a balanced effect on the valve body 49.
No matter how much this pilot pressure is, the poppet valve portion 50 will not open unless the pilot pressure acts on the valve body 49 through the second pilot line 60.

Next, when the directional control valve 3 is switched to the A position, the hydraulic power source 1
Pressure oil supplied from pipe 75. A check valve 77 disposed within the conduit 76, a conduit 72. The cylinder 4 passes through the conduit 71.
is supplied to the rod chamber, and the load 5 is lifted. A part of the pressure oil supplied from the hydraulic source flows into the outflow hole A1 through the pipe line 74, and at the same time flows into the large diameter hole 44 through the pipe line 81 and the second communication path 45. The flow is blocked by the poppet valve body 24 and the poppet valve portion 50.

On the other hand, the oil in the head chamber of the cylinder 4 is discharged into the tank 2 through a pipe 78.

When the directional control valve 3 is switched to the B position, the pressure oil supplied from the hydraulic source 1 is supplied to the head chamber of the cylinder 4 through the pipe 78. At this time, a part of this pressure oil flows into the pressurizing chamber 59 as a pilot liquid through the pipe line 80 and the second pilot channel 60, and acts on the back of the sliding portion 53 of the valve body 49. When this pilot pressure overcomes the biasing force of the return spring 58, the valve body 49 is slid downward, and the poppet valve portion 50
is separated from the valve seat 48, and the large diameter hole 44 and the sliding hole 43 communicate with each other. As a result, the pressure oil in the action chamber 31 is transferred to the flow path 34 and the flow path 41.
, sliding hole 43, large diameter hole 44, second communication path 45, pipe line 81
, through line 75 to tank 2=16-. Therefore, the pilot pressure acting on the back of the poppet valve body 24 decreases, and on the other hand, the pressure oil sent from the rod chamber of the cylinder 4 acts on the truncated cone portion 25 of the poppet valve body 24, so this pressure causes the truncated cone portion 25 to Valve seat 23
The inflow hole A2 and the outflow hole A1 communicate with each other.

As a result, the oil in the rod chamber side of the cylinder 4 passes through the pipes 71, 72, 73, 74, and 75 and is discharged into the tank 2, and the load 5 is accordingly lowered. that time,
When the load 5 falls rapidly, the pressure in the conduit 78 decreases,
Since the pilot pressure acting on the valve body 49 through the second pilot flow path 60 also decreases, the valve body 49 slides upward by the return spring 58, and the poppet valve portion 50 seats on the valve seat 48 and the slide hole 49 and the large diameter hole 44. As a result, the discharge of the pressure oil from the working chamber 31 is stopped and the pilot pressure in the working chamber 31 increases, so that the poppet valve body 24 again blocks the inflow hole A2 and the outflow hole A1. As a result, the oil discharge from the rod chamber of the cylinder 4 is stopped, and the load 5 is prevented from falling rapidly.

(Effects of the Invention) According to the present invention, since the inflow hole and the outflow hole are configured to be communicated and cut off by the poppet valve body, there is no liquid leakage when shutting off, which occurs in valves with a spool structure, and loads such as shilling can be reliably handled. It is possible to lock and prevent the product from falling due to its own weight, and there is no need to use a pilot check valve that requires troublesome pilot pressure adjustment to prevent liquid leakage. Furthermore, since the discharge of the pilot liquid for opening and closing the poppet valve element is controlled by another pilot-operated valve element, it is possible to control a large amount of pressurized liquid with a small amount of pilot liquid. Furthermore, since a poppet valve portion is formed on this valve body, when this poppet valve portion is closed, there is no leakage of the pilot liquid, and therefore, the opening of the inflow hole and the outflow hole can be reliably blocked by the poppet valve body. Furthermore, the pilot pressure required to open the valve body that forms the poppet valve part is set only by the return spring, and does not depend on the size of the load, so the pressure in the pipe that takes out this pilot pressure will not change significantly when the load is lowered. Schilling shock can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the first embodiment of the present invention, Fig. 2 is a Schilling self-weight fall prevention circuit to which the first embodiment is applied,
The figure shows a conventional Schilling fall prevention circuit. A1... Outflow hole A2... Inflow hole 24... Poppet valve body 27... Return spring 31... Action chamber 3
2... Crest 33... First pilot channel 34.
4i...First communication path 43...Sliding hole 44...
Large diameter hole 45...Second communication path 48...Valve seat 49.
...Valve body 50...Poppet valve part 53...Sliding part
54-...Connection shaft portion 58...Return spring 60...
Second pilot flow path

Claims (1)

[Claims] A poppet valve body (24) that blocks communication between the inflow hole (A2) and the outflow hole (A1), and a first valve that guides the pilot liquid to an action chamber (31) formed at the back of the poppet valve body (24).
A pilot flow path (33) and the first pilot flow path (3
3) and the emblem (32) interposed in the poppet valve body (24)
A return spring (27) that is attached to one end and biases the poppet valve body (24) in the closing direction, a pilot of the action chamber (31) that is connected to the action chamber (31), and a large diameter hole ( 44)
and a valve seat (48) formed in the connecting step of the sliding hole (43), and a second communicating path (45) connected to the large diameter hole (44).
The valve seat (48) has a first communication passage (3) at one end that discharges the liquid.
4, 41), a small diameter sliding hole (43) connected to the first communicating path (34, 41), and a large diameter hole (44) connected to the sliding hole (43). The sliding hole (43) and the large diameter hole (
44) A poppet valve part (50) is formed for communicating and blocking communication between the poppet valve part (50), and a sliding part (53) is formed at the other end to slidably fit into the sliding hole (43). and the sliding part (53) are connected by the connecting shaft part (54), and the first communication path (3
A valve body (49) on which the hydraulic pressure of 4, 41) acts in equilibrium, and a return spring that is engaged with the valve body (49) and urges the poppet valve portion (50) to seat on the valve seat (48). (58) and
A pilot operation characterized by comprising a second pilot flow path (60) through which a pilot liquid acts on the valve body (49) so that the poppet valve portion (50) separates from the valve seat (48). type on-off valve.