JP4424674B2 - Pressure reducing valve - Google Patents

Description

  The present invention relates to a pressure reducing valve for reducing pressure entering from a primary side inlet and outputting from a secondary side outlet, and more particularly to a pressure reducing valve in a pneumatic circuit, in addition to an original pressure reducing function, a pressure drop on a primary side The present invention relates to a pressure reducing function-equipped pressure reducing valve having a function of maintaining the pressure on the secondary side.

  The pneumatic circuit is a technique for operating various types of operating devices, and this type of pressure reducing valve is essential. The operating source of the pneumatic circuit is compressed air produced by the compressor. The compressed air is firstly dusted through an air processing device such as an air dryer, oil and moisture are removed, and the processed compressed air is supplied to the primary inlet of the pressure reducing valve. Then, the compressed air is reduced to a more stable pressure by the pressure reducing valve, and is output from the secondary side outlet of the pressure reducing valve to the operating device.

As one of such pressure reducing valves, there is a type in which a pressure to be reduced is set using a piston as disclosed in Patent Document 1. The piston receives the force of the pressure setting spring at one end and the secondary pressure at the other end. The piston is accompanied by a valve body, and can move with a change in pressure. Therefore, when the secondary side pressure reaches the set pressure due to the supply pressure from the primary side, the valve body comes into contact with the valve seat provided on the valve housing side and stops the increase of the secondary side pressure (depressurized state).
Japanese Patent Laid-Open No. 10-220613

  In the conventional pressure reducing valve, when the primary pressure is reduced when the pressure is reduced, the secondary pressure is also reduced following the decrease. Therefore, in the pneumatic circuit, when the air dryer or the like upstream of the pressure reducing valve is removed (such a case occurs when the air dryer is maintained or parts are replaced), the downstream operating device (for example, the automatic door of the bus) This causes a situation where the door engine for opening and closing cannot be operated. For example, there is a disadvantage that the door cannot be opened and closed during the maintenance of the air dryer.

  In order to eliminate such inconvenience, it is conceivable to attach a check valve to the pressure reducing valve. However, if a check valve is simply added, the pressure reducing valve will increase in size as much as the check valve. In addition, existing pressure reducing valves, including valve housings, must be changed considerably, and existing components cannot be used effectively.

Accordingly, the present invention can make the pressure reducing valve function as a check valve (that is, a pressure holding function) by making a slight change to the existing one while effectively utilizing the components of the existing pressure reducing valve. The purpose is to provide technology that can be used.
Other objects of the present invention will become clear from the following description.

  The basic idea of the present invention is to make the valve seat on which the valve body is attached and detached movable (movable relative to the valve housing). In conventional pressure reducing valves, the valve seat is always integral with the valve housing, and there is no relative movement between the valve seat and the valve housing. The present invention is based on a novel concept of making the valve seat that has been stationary movable.

  By making the valve seat movable, the valve body that is attached to and detached from the valve seat has the function of a check valve (or pressure holding function), and the secondary side pressure drop due to the primary side pressure drop described above. Can be prevented. In that respect, the effect of the movable valve seat can be known by considering why the secondary pressure decreases. When the primary side pressure decreases in the reduced pressure state, the secondary side pressure separates the valve body from the valve seat, so that the secondary side pressure also leaks to the primary side, and the secondary side pressure also decreases accordingly. When the secondary side pressure decreases, the piston pressure setting spring moves the piston from the primary side to the secondary side. The valve body moves along with the movement of the piston. In the conventional pressure reducing valve, the valve body has to be separated from the stationary valve seat, but in the pressure reducing valve of the present invention, the valve seat is movable, so the movable valve seat follows the movement of the valve body. In addition, the secondary pressure can be maintained in cooperation with the valve body.

  Making the valve seat movable can be accommodated with slight changes around the existing valve seat. That is, the valve seat may be constituted by a ring member separate from the valve housing, and the position of one side of the ring member may be restricted by the stopper while the other side may be restricted by the return spring.

  1 to 3 show different states of a preferred embodiment of the pressure reducing valve of the present invention. 1 shows a no-pressure state and a state before pressure reduction, FIG. 2 shows a pressure-reduced state, and FIG. 3 shows a state where the primary side has no pressure. Therefore, the pressure reducing valve 10 as an embodiment will be clarified with reference to those drawings.

  The main components of the pressure reducing valve 10 are a valve housing 20 that partitions an internal space (so-called valve chamber) 200, a pressure setting piston 30 in the internal space 200, a valve body 50 that follows the movement of the piston 30, and The ring member 70 is a valve seat for the valve body 50.

  The internal space 200 of the valve housing 20 is in the form of a cylinder hole. The large diameter hole 201, the first medium diameter hole 202, the second medium diameter hole 203, and the small diameter hole 204 are arranged in the vertical direction with the axis centering in that order. It is continuous. The valve housing 20 includes two pipe connection ports 21 and 22 on the same side surface. These two pipe connection ports 21 and 22 are arranged in the vertical direction, and their axial centers are parallel to each other. The upper pipe connection port 22 opens to the first medium diameter hole 202, and the lower pipe connection port 21 opens to the second medium diameter hole 203. The pipe connection port 22 located on the upper side is the secondary side outlet, and the pipe connection port 21 located on the lower side is the primary side inlet.

  Next, let us look at the inside of the internal space 22 of the valve housing 20. The piston 30 is located in a portion from the large diameter hole 201 to the second medium diameter hole 203 in the internal space 22. The piston 30 integrally includes a large-diameter portion 301 that fits into the large-diameter hole 201 and a cone portion 302 that extends from the lower end of the large-diameter portion 301. The large-diameter portion 301 has a cylindrical shape, and the inner concave portion 301h receives most of the coil spring 34 for pressure setting. The bottom of the recess 301 h supports one end of the coil spring 34, and the lid component 40 positioned at the opening of the large-diameter hole 201 supports the other end of the coil spring 34. A set pressure adjusting means including a screw 42 is attached to the lid constituent member 40.

  The piston 30 holds a seal ring 32 at the upper portion of the outer peripheral side surface, and the seal ring 32 hermetically partitions the side where the coil spring 34 is located and the lower side of the cone portion 302. The side on which the coil spring 34 is provided communicates with the atmosphere through the air holes of the lid component 40, while the lower side of the cone 302 is a pressure chamber that receives the pressure on the primary side and the secondary side. . The piston 30 is movable in the vertical direction at the large diameter portion 301 along the inner peripheral wall of the large diameter hole 201. When such movement is performed, the piston 30 is guided at both the upper and lower ends of the large-diameter portion 301, and thus can move smoothly without causing a twist or the like. The portions that guide the piston 30 are an upper land 301 a that defines a ring groove into which the seal ring 32 is inserted, and a lower land 301 b on the lower end side of the large diameter portion 301.

  The cone portion 302 of the piston 30 includes a passage 302p that passes through the center. The passage 302p has an upper end opened to the recess 301h and a lower end opened to the second medium-diameter hole 203. The small piston-like valve body 50 is located below the cone portion 302 so as to block the lower opening of the passage 302p. Here, the small piston is a word that means a smaller piston than the piston 30. The valve body 50 includes a main body portion 501 having a stepped structure and a rubber portion 502 attached to an end surface of the main body portion 501. Such a valve body 50 also has a central hole 503 that penetrates the rubber portion 502 and the main body portion 501. The main body portion 501 of the valve body 50 fits into the small diameter hole 204 of the valve housing 20 and can move in the vertical direction. The valve body 50 carries a seal ring 52 on the outer periphery of the main body portion 501 and a valve spring 54 on the end opposite to the rubber portion 502. The force of the valve spring 54 is extremely small as compared with that of the coil spring 34 for setting the pressure. However, the small piston-like valve body 50 receives the force of the valve spring 54 and causes the rubber portion 502 to be a cone of the piston 30. It is applied to the lower end of the portion 302. Therefore, the valve body 50 can block the portion to which the pressure on the primary side and the secondary side is applied from the atmosphere (or atmospheric pressure) by the connection of the cone portion 302 / rubber portion 502 and the sealing function by the seal ring 52. it can.

  Now, pay attention to the outer peripheral portion of the cone portion 302 of the piston 30. A valve seat for the valve body 50 is provided on the outer peripheral portion. Whereas the conventional valve seat has always been a fixed valve seat integrated with the valve housing 20, the present invention makes the valve seat movable. The valve seat according to the present invention includes a ring member 70 that is separate from the valve housing 20, and supports the ring member 70 so as to be movable with respect to the valve housing 20. The ring member 70 has an outer diameter that fits into the second medium-diameter hole 203 and holds a seal ring 72 on the outer periphery. In addition, the inner diameter of the ring member 70 is set smaller than the outer diameter of the rubber portion 502 of the valve body 50, whereby the rubber portion 502 of the valve body 50 is seated on one surface (that is, the lower surface) of the ring member 70. It is like that. In such a ring member 70, the position of the upper surface of the ring is restricted by a stopper 76 made of a C-shaped ring, whereas the lower surface is only restrained by a return spring 74.

  Since the stopper 76 is located above the second medium-diameter hole 203, the ring member 70 is located between the side communicating with the primary side inlet 21 and the side communicating with the secondary side outlet 22. Since the ring member 70 has the stopper 76, the ring member 70 cannot move upward beyond the stopper 76, but can move downward than the stopper 76 while deforming the return spring 74. In other words, in the present invention, only a partial change is made to make the ring member 70 movable. Such a change can be easily dealt with by utilizing an existing one. However, although it is a slight change, it is possible to bring a new effect of the pressure holding function to the pressure reducing valve 10 by the change.

  In the no-pressure state and before pressure reduction shown in FIG. 1, the ring member 70 maintains a position where the upper surface hits the stopper 76 by the force of the return spring 74, thereby passing through the inner periphery of the ring member 70 from the primary side inlet 21. An air passage leading to the secondary side outlet 22 is secured. From such a state, when compressed air (pressure) is supplied through the primary side inlet 21 and the supplied pressure reaches the set pressure of the pressure reducing valve 10, the piston 30 moves upward while deforming the coil spring 34. 2 to the reduced pressure state. When shifting to the reduced pressure state as described above, the valve body 50 receives the force of the valve spring 54 and follows the movement of the piston 30. Therefore, the valve body 50 (that is, the rubber portion 502 of the valve body 50) is in contact with the lower surface of the ring member 70 that is the valve seat, blocks the air passage, and stops the increase (pressurization) of the secondary side pressure. . When the primary pressure is supplied and the secondary pressure becomes excessive, the piston 30 receiving the excessive secondary pressure overcomes the force of the coil spring 34, and the lower end of the cone 302 is It leaves | separates from the rubber part 502 of the valve body 50. FIG. Accordingly, an excessive secondary pressure can be released to the atmosphere through the passage 302p that penetrates the center of the cone portion 302.

  The pressure reducing valve 10 generates functions such as pressure reduction and relief, and also has a function of maintaining the secondary pressure. It is assumed that a situation occurs in which the primary pressure is lower than the secondary pressure in the reduced pressure state. In such a case, since the ring member 70 is movable, the ring member 70 is pushed downward by the secondary side pressure and can maintain the state in contact with the valve body 50. Therefore, the air passage which connects the secondary side and the primary side can be shut off, and the secondary side pressure can be maintained.

It is sectional drawing of the pressure-reduction valve of one Example of this invention, and has shown the state before a pressureless state and pressure reduction. It is sectional drawing which shows the pressure reduction state of the pressure reducing valve of FIG. FIG. 2 is a cross-sectional view showing a state where no pressure is applied to the primary side in the pressure reducing valve of FIG. 1.

Explanation of symbols

10 Pressure reducing valve 20 Valve housing 201 Large diameter hole (piston guide hole)
203 Second medium-diameter hole (ring member guide hole)
21 Primary side inlet 22 Secondary side outlet 200 Internal space 30 Piston 50 Valve body 70 Ring member (valve seat)
74 Return spring 76 Stopper

Claims (4)

A pressure reducing valve for reducing the pressure entering from the primary side inlet and outputting from the secondary side outlet,
A valve housing having a primary side inlet and a secondary side outlet defining an internal space and communicating with the internal space, respectively;
A piston located in the internal space of the valve housing, having a communication hole leading from one end to the other end, receiving a force of a pressure setting spring at one end, and receiving a secondary pressure at the other end;
A valve body that is opposite to the other end of the piston and that can open and close a communication hole that opens to the other end;
A ring shape that communicates with the primary side inlet and the secondary side outlet through a hole on the inside of the ring, and a ring member on which one side of the ring serves as a valve seat of the valve body,
This ring member has a pressure-reducing valve in which the movement toward the side facing the secondary side outlet is restricted by the stopper, whereas the movement toward the side facing the primary side inlet is only restricted by the return spring. .   The reduced pressure according to claim 1, wherein when the pressure on the primary side decreases in the reduced pressure state in which the valve body is in contact with the ring member, the ring member is pressed by the pressure on the secondary side to maintain the state in contact with the valve body. valve.   The pressure reducing valve according to claim 1, wherein the valve housing has a piston guide hole for guiding the piston and a ring member guide hole for guiding the ring member.   The pressure reducing valve according to claim 1, wherein the valve body is a small piston that moves while being guided by the valve housing.

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