JPH0741153U - Pilot operated check valve - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a pilot-operated check valve that has a flow rate adjusting function and that has excellent workability in component parts while maintaining operating characteristics without shock. [Structure] An annular valve seat provided in a flow path between a supply / discharge port and a load port, the annular valve seat is closed by pressure of the load port and a cracking spring force, and the annular valve is formed by pressure on the supply / discharge port side. A check valve element that separates from the seat, a pilot piston that presses the check valve element when it receives pilot pressure and separates from the annular valve seat, and a pilot piston that projects from the tip of the pilot piston so that it can contact the check valve element. ,
The annular valve seat is closed with a predetermined overlap amount, and when the pilot piston separates the check valve body from the annular valve seat, the communication opening degree between the supply / discharge port and the load port is set in the annular valve seat. A flow rate adjusting valve body to be opened
There is provided a flow rate adjusting means that adjusts the limit position of movement of the check valve element in the seat separating direction from the outside.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pilot-operated check valve used, for example, for holding the position of a hydraulic actuator, and in particular, it has a function to adjust the flow rate of pressure oil that is opened when the pilot operation is performed. It is related to the type of pilot operation check valve.

[0002]

[Prior art]

 As a conventional example of a pilot operated check valve having a flow rate adjusting function, for example, there is one known from Japanese Utility Model Publication No. 4-136372. This conventional pilot operated check valve has a relatively large diameter check valve body that closes the large-diameter valve seat between the load flow passage and the supply / discharge flow passage by the pressure oil from the load flow passage and the spring force. And a small-diameter check valve body that closes the load flow path and the supply / discharge flow path in parallel by being seated by the spring on a small-diameter valve seat arranged inside the check valve body. Free flow from the supply / exhaust flow path to the load flow path is achieved by separating the large-diameter check valve body from the large-diameter valve seat against the spring by the pressure oil pressure from the supply / exhaust flow path side. For the reverse flow from the load flow path to the supply / exhaust flow path, the pilot piston causes the small-diameter check valve body to move away from the small-diameter valve seat, and the position of the backward movement of the small-diameter check valve body for this separation is adjusted in advance. So that the desired regulated flow rate can be obtained. To have.

[0003]

[Problems to be solved by the device]

 In this conventional pilot operated check valve, a cylindrical head that is inserted in a small-diameter valve seat by oil-tight fitting is integrally formed with the small-diameter check valve body so that a rapid rise of the flow rate does not occur at the start of reverse free flow. Therefore, when machining large-diameter check valve bodies and small-diameter check valve bodies, the inner peripheral surface of the large-diameter check valve bodies and the outer peripheral surface of the small-diameter check valve bodies that should be fitted to them, and the large-diameter check valve The small-diameter valve seat formed inside the body and the small-diameter valve body poppet seal to be seated there, the small-diameter valve seat inner hole of the large-diameter check valve body, and the small-diameter check valve body to be oil-tightly fitted thereto It is necessary that the three pairs with the cylindrical head be coaxial, and this coaxial accuracy greatly affects the internal leakage performance of the valve.Therefore, when working the small-diameter check valve body and the large-diameter check valve body, respectively. Extremely high coaxial accuracy at three locations There is a problem that must be earned.

The present invention has a flow rate adjusting function and prevents sudden rise of flow rate at the start of reverse flow to maintain shock-free operation characteristics, and at the time of machining components such as a check valve body. It is an object of the present invention to provide a pilot-operated check valve with excellent workability, which requires the coaxial precision of at most two places instead of the coaxial precision of three places.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, in the pilot operated check valve of the invention according to claim 1, an annular valve seat provided on the inner peripheral surface of the flow path connecting the pressure oil supply / discharge port and the load port of the valve body. And is seated on the annular valve seat by the pressure oil pressure guided from the load port and the spring force of the cracking spring to close the ring valve seat, and the pressure oil pressure on the pressure oil supply / discharge port side resists the spring. And a check valve element that opens the annular valve seat by moving away from the annular valve seat, and abuts against the check valve element when it receives pilot pressure oil pressure and presses it against the spring. And a pilot piston that is moved away from the annular valve seat by means of a protrusion projecting from the tip of the pilot piston so that it can contact the check valve body, and the annular valve seat is closed with a predetermined overlap amount. In both cases, when the pilot piston disengages the check valve body from the annular valve seat, the pressure oil supply / discharge port and the load port gradually move after the movement of the overlap amount or more in the annular valve seat. A flow rate adjusting valve element that sets the communication opening degree to a predetermined flow rate adjusting opening degree, and a movement limit position of the check valve element in the seating direction for adjusting the flow rate adjusting opening degree are externally adjustable. And a flow rate adjusting means.

In this case, preferably, the flow rate adjusting means is axially retractable against the spring by a predetermined distance when in the fully closed position where the flow rate is zero. An outer peripheral surface is formed that can close the annular valve seat with the overlap amount longer than the distance when the flow rate adjusting unit is in the fully closed position where the flow rate is zero.

[0007]

[Action]

 In the pilot operated check valve according to the present invention, the check valve body performs the check valve function exclusively, and the flow rate adjusting function is performed not by the head of the check valve body but by the flow rate adjusting valve body protruding from the pilot piston. Moreover, the check valve body and the flow rate adjusting valve body cooperate with a common annular valve seat to perform their respective functions. Therefore, since the check valve body and the flow rate adjustment valve body are configured as separate parts with respect to the annular valve seat, a plurality of coaxial parts are included in each component that constitutes the valve function element of the pilot operated check valve with the flow rate adjustment function. It is not necessary to machine to secure accuracy at the same time, and machining of parts is much easier than the conventional one.

[0008]

【Example】

FIG. 1 shows the construction of the pilot operated check valve according to the embodiment of the present invention together with various operating states. In Fig. 1, the right side shows the flow rate adjusting screw in the fully closed position and the left side shows the flow rate adjusting screw in the fully open position. The upper halves are from port A ₁ to port A ₂ and port B _{2 respectively.} To port B ₁ and the lower half shows the neutral condition. The embodiment shown in FIG. 1 is of a laminated valve type having both A and B port functions, but the present invention is also applicable to a type having only one port function of A or B. It goes without saying that it can be applied to types other than the valve type.

In FIG. 1, a valve body 1 includes a pair of pressure oil supply / discharge ports A ₁ and B ₁ which are opened on an upper surface which is a laminated surface with a valve laminated on an upper portion, and a valve or a manifold laminated on a lower portion. It has a pair of load ports A ₂ and B ₂ opened on the lower surface which is a stacking surface with the block, and these ports are connected to a flow path (external flow path) in an adjacent valve or manifold block in a stacked state.

Inside the valve body 1, the A side and the B side are symmetrical with respect to the central pilot operating piston 2, and if the A side is explained _first , the ports A ₁ and A ₂ are connected. The body 1 is provided with an annular valve seat 3a so as to be located in the flow passage. The seat portion of the annular valve seat 3a is provided with a check valve body 4a from the side opposite to the piston 2. It is possible to sit on the conical surface of.

The check valve body 4a receives the force of a spring 7a supported by a retainer 9a attached to the end of the valve body 1 from the tail end side, and is thereby seated on the annular valve seat 3a. A plurality of radial openings 41a are formed on the peripheral surface of the check valve body 4a closer to the tail end than the conical surface. The openings 41a communicate with the spring chamber 6a in which the spring 7a is arranged, The pressure on the load port A ₂ side is always guided to the spring chamber 6a through the opening 41a. A play amount v is applied between the check valve body 4a and the tip of the piston 2.

What is screwed to the retainer 9a is a flow rate adjusting screw 5a which is set so that the backward limit position of the check valve body 4a can be adjusted by a turning operation by a handle or the like. As shown in the right side of FIG. Even when the adjusting screw 5a is in the fully closed position, the check valve body 4a can be retracted by the minimum stroke amount x. This minimum stroke amount x is the flow rate control when the adjusting screw 5a is in the fully closed position. The overlap amount y, which will be described later, is selected so that the parts do not open.

The above is the configuration of the check valve on the A side, but the B side is also configured to be bilaterally symmetrical with a substantially similar structure. However, in FIG. 1, the position of each part on the B side shown on the left side is a state in which the adjusting screw 5b is at the fully open position and the flow rate control part is at the fully open position, and the other parts are the same as those on the A side. ..

The pilot operation piston 2 located in the center projects piston rods 2a and 2b to the left and right, and reverse taper shaped flow rate adjusting valve bodies 8a and 8b are provided at their respective tips. Each of the flow rate adjusting valve bodies 8a and 8b gradually opens the communication opening degree with the annular valve seat 3a when it enters the annular valve seat 3a and further passes therethrough, and the check valve bodies are in contact with the front end face. When the flow rate adjusting screws 5a and 5b reach the retracted limit positions 4a and 4b, the flow rate control unit F having a set opening degree is formed between the flow rate adjusting screws 5a and 5b and the annular valve seat 3a.

Each of the flow rate adjusting valve bodies 8a, 8b is provided with a cylindrical outer peripheral surface 81a, 81b that is oil-tightly fitted into the annular valve seat 3a at each tip, and the cylindrical outer peripheral surface 81a, 81b and each valve seat. The dimension w of the overlap portion formed by the inner diameter portions of 3a and 3b is such that when the flow rate adjusting screw 5a or 5b is in the fully closed position where the flow rate is zero, the annular valve seat 3a is smaller than the minimum stroke amount x. It is defined to satisfy y = wv> x so as to be closed with a long overlap amount y.

The pilot piston 2 moves leftward by using the pilot piston 2 as a pilot pressure when a pressure is introduced to the port A ₁ , and the flow rate adjusting valve element 81b protruding at the tip of the pilot piston 2 is provided in the annular valve seat 3b. The check valve body 4b is pushed and moved to the backward limit position set by the adjusting screw 5b. At this time, when the cylindrical outer peripheral surface 81b of the flow rate adjusting valve body 8b that contacts the check valve body 4b passes through the annular valve seat 3b, the flow rate control unit F between the annular valve seat 3b and the annular valve seat 3b is gradually opened to the set opening. Therefore, the flow rate adjustment function is fulfilled. On the contrary, when the pressure is introduced to the port B ₁ side, the pilot operating piston 2 moves the A side check valve body 4a to the right side to its retracted limit position, which is the same as the above in the case of the reverse flow. Various flow rate adjusting functions are performed by the flow rate adjusting valve body 8a.

In the above-described embodiment, the case where the flow rate control unit F is formed by the seat opening shoulder of the annular valve seat and the reverse tapered conical surface of the flow rate adjusting valve body has been described. Instead of the surface, the flow rate control unit can be configured by forming a concave portion or a V groove by end milling while leaving an overlapping amount on the cylindrical outer peripheral surface of the flow rate adjusting valve body.

Now, assuming that a pump and a tank line are connected to the ports A ₁ and B ₁ via a directional control valve in FIG. 1 and a reciprocating actuator is connected to the ports A ₂ and B ₂ , First, when the pressure oil from the pump line is supplied to the port A ₁ , when the supply pressure exceeds the cracking pressure determined by the spring 7a, the check valve body 4a moves to the right while bending the spring 7a. As a result, the annular valve seat 3a is opened, so that free flow flows to the actuator.

Further, at this time, the piston 2 is moved leftward by using the pressure oil pressure supplied to the port A ₁ as a pilot pressure, and the flow rate adjusting valve body 8b projecting at the tip of the piston rod 2b is on the B side. It contacts the check valve body 4b and is pushed against the spring 7b. When the flow rate adjusting valve body 8b comes into contact with the check valve body 4b and then moves to the left by the above-mentioned lift amount v, the check valve body 4b separates from the annular valve seat 3b, but the check valve body 4b does not move. Even if it is separated from 3b, the annular valve seat 3b remains closed while the movement amount of the flow rate adjusting valve body 8b is within the range of the overlap amount y. At this time, the pressure of the return pressure oil from the actuator port B ₂ is acting, the spring chamber 6b is communicated to port B ₂ via the opening 41b, impede the movement of the check valve element 4 b There is no need to be.

When the amount of movement of the check valve body 4b exceeds the overlap amount y, the annular valve seat 3b is gradually opened by the reverse tapered conical surface of the flow rate adjusting valve body 8b, which allows shockless type flow rate control. Be started. It goes without saying that the final opening degree of the flow rate control unit F is determined by the check valve body 4b reaching the backward limit position set by the flow rate adjusting screw 5b. In this way, the return pressure oil flowing into the port B ₂ is adjusted in a meter-out manner by the flow rate control unit F formed between the reverse tapered conical surface of the flow rate adjusting valve body 8b and the annular valve seat 3b. You will exit from port B ₁ .

Conversely, when pressure oil is supplied to the port B ₁ side from the pump line, the same operation as described above is performed symmetrically.

[0022]

[Effect of device]

 As described above, according to the pilot operated check valve of the present invention, the flow control section is formed not between the head of the check valve body but between the flow control valve body on the pilot piston side and the annular valve seat. Moreover, the check valve body and the flow rate adjusting valve body cooperate with the common annular valve seat to perform their respective functions, and the check valve body and the flow rate adjusting valve body are configured as separate parts with respect to the annular valve seat. Therefore, it is not necessary to make a work that simultaneously secures multiple coaxial accuracy for each part that constitutes the valve function element of the pilot-operated check valve with flow rate adjustment function. The result is that it is significantly easier.

[Submission date] October 31, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

[Prior art]

As a conventional example of a pilot operated check valve having a flow rate adjusting function, for example, there is one known from Japanese Utility Model Publication No. 4-136372. This conventional pilot operated check valve has a relatively large diameter check valve body that closes the large-diameter valve seat between the load flow passage and the supply / discharge flow passage by the pressure oil from the load flow passage and the spring force. And a small-diameter check valve body that closes the load flow path and the supply / discharge flow path in parallel by being seated by the spring on a small-diameter valve seat arranged inside the check valve body. Free flow from the supply / exhaust flow path to the load flow path is achieved by separating the large-diameter check valve body from the large-diameter valve seat against the spring by the pressure oil pressure from the supply / exhaust flow path side. reverse flow from the load passage to supply and discharge flow path, together with Ru unseats the small diameter check valve body from the small-diameter valve seat by the pilot piston, precondition the position of the retracting movement of the small diameter check valve body for the unseated So that the desired adjusted flow rate can be obtained. You have me.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a pilot operated check valve throttle check valve according to an embodiment of the present invention together with various operating states.

[Explanation of symbols]

1 Valve body 2 Pilot operation piston 2a, 2b Piston rod 3a, 3b Annular valve seat 4a, 4b Check valve body 5a, 5b Flow rate adjusting screw 6a, 6b Spring chamber 7a, 7b Spring 8a, 8b Flow rate adjusting valve body 9a, 9b Retainer 41a, 41b Opening A ₁ , B ₁ Pressure oil supply / discharge port A ₂ , B ₂ Load port

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[Procedure amendment]

[Submission date] October 31, 1994

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG. 1 is a pilot operation check according to an embodiment of the present invention.
It is sectional drawing which shows the structure of a valve together with various operating states.

Claims (1)

[Scope of utility model registration request] 1. An annular valve seat provided on an inner peripheral surface of a flow path connecting a pressure oil supply / discharge port of a valve body and a load port, a pressure oil pressure introduced from the load port and a spring of a cracking spring. A check valve that is seated on the annular valve seat by a force to close the annular valve seat and that opens the annular valve seat by separating from the annular valve seat against the spring by the pressure oil pressure on the pressure oil supply / discharge port side. A body, a pilot piston that abuts against the check valve body when it receives pilot pressure oil pressure, and pushes it against the spring to separate it from the annular valve seat; The pilot piston is provided so as to be contactable with the pilot piston, and the annular valve seat is closed by a predetermined overlap amount, and the pilot piston separates the check valve body from the annular valve seat. When this is done, the flow rate adjustment valve body gradually changes the communication opening degree between the pressure oil supply / discharge port and the load port to a predetermined flow rate adjustment opening degree after the movement of the overlap amount or more in the annular valve seat. And a flow rate adjusting means that adjusts the movement limit position of the check valve body in the separating direction from the outside in order to adjust the flow rate adjusting opening, and a pilot operated check valve. .