JP2011064221A - Exhaust valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a sounding phenomenon of an exhaust valve caused by the opening and closing motion of a valve element. <P>SOLUTION: In the exhaust valve 23, when pressure in a primary side port 24 becomes equal to or larger than a predetermined pressure, the valve element 34 separates from a valve seat 35 and releases gas in the primary side port 24 to an atmospheric pressure port 25 to adjust the pressure in the primary side port 24. A shuttle 33 is contained in a casing 31 to reciprocate in the axial direction and the shuttle 33 is provided with a pressure receiving head 33a forming a pressure chamber 47 which has a cross sectional area larger than the cross sectional area of an air flow passage formed between the valve element 34 and the valve seat 35. In the casing 31, the valve element 34 is provided with a holder 36 holding a spring member for closing the primary side port 24 and there is provided a discharge flow passage having a cross sectional area smaller than the cross sectional area of the pressure chamber 47. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust valve that is provided in a pneumatic circuit and discharges compressed air to the outside to keep the pressure in the pneumatic circuit at a set value.

  In a pneumatic circuit that supplies compressed air to a pneumatic device, a relief valve, that is, an exhaust valve is used to discharge the compressed air to the outside and maintain the pressure in the pneumatic circuit at a set value. An exhaust valve is also referred to as a safety valve when it is used to prevent destruction of pneumatic equipment and piping forming a pneumatic circuit. As such an exhaust valve, for example, there is an exhaust valve having a poppet type valve body as described in Patent Document 1.

  In a pneumatic circuit in which compressed air is supplied to a pneumatic cylinder as a pneumatic device and the piston rod of the pneumatic cylinder is reciprocated linearly, the compressed air applied to the piston during the forward and backward movement of the piston rod The pressure may be different. In such a pneumatic circuit, an exhaust valve may be used in order to make the constant pressure compressed air supplied by being regulated from a pneumatic pressure source differ between when the piston rod moves forward and when it moves backward. For example, in a pneumatic circuit in which the piston rod of a pneumatic cylinder is moved forward or moved forward to open the door, and the piston rod is moved backward or moved backward to close the door, the pneumatic cylinder is connected to the pneumatic cylinder when the door is opened. An exhaust valve is used to lower the pressure supplied to the pneumatic cylinder when closing the door than the supplied pressure.

  An exhaust valve used in such a pneumatic circuit supplies compressed air set to a pressure for moving the piston rod forward to a pneumatic cylinder by reducing the pressure when moving the piston rod backward. become.

JP 2004-1000093 A

  When the pressure of the primary port connected to the air pressure source is higher than the set pressure, the exhaust valve opens the primary port with a poppet type valve body and discharges the air of the primary port to the atmospheric pressure port Therefore, when the difference between the pressure of air supplied from the air pressure source and the adjustment pressure set by the exhaust valve is large, the valve body vibrates so as to open and close the primary port frequently, and the valve Sound resonance occurs due to body resonance. This sounding phenomenon occurs when the valve body frequently opens and closes the primary side port. Therefore, as described in Patent Document 1, avoiding the occurrence of lateral vibration of the valve body is avoided. Can not do it.

  An object of the present invention is to prevent the occurrence of a noise phenomenon of an exhaust valve.

  The exhaust valve of the present invention closes the primary side port by closing a valve body by a spring force against a valve seat provided on the primary side port, and the pressure of the primary side port is equal to or higher than a predetermined pressure. An exhaust valve that adjusts the pressure of the primary port by releasing the gas of the primary port to the atmospheric pressure port away from the valve seat, the primary port and the other end provided at one end A housing for forming a housing hole communicating with the atmospheric pressure port provided at a portion and the valve body for reciprocatingly moving the shuttle provided at one end in the axial direction; and one end of the shuttle A pressure chamber having a cross-sectional area larger than a cross-sectional area of an air flow path formed between the valve body and the valve seat when the valve body is separated from the valve seat; A pressure receiving head formed between the shuttle and the housing; A holder formed with a guide hole that holds a spring member that applies a spring force toward the valve seat with respect to the valve body, and has a guide hole into which the other end of the shuttle enters, and a cross-sectional area of the pressure chamber. It has a narrow cross-sectional area, and has a discharge passage for restricting air flowing in the axial direction from the pressure chamber toward the atmospheric pressure port.

  The exhaust valve of the present invention is characterized in that the discharge flow path is formed between the guide hole of the holder and the outer peripheral surface of the other end of the shuttle. The exhaust valve of the present invention communicates with an outer discharge passage formed between the guide hole of the holder and the outer peripheral surface of the other end of the shuttle, and an exhaust inlet formed in the pressure receiving head. The discharge channel is formed by an inner discharge channel formed in the shuttle. The exhaust valve of the present invention is provided with a stopper surface on the holder that the pressure receiving head abuts to regulate the open limit position of the valve body, and the pressure receiving head abuts on the stopper surface. Air in the pressure chamber is guided to the atmospheric pressure port via the inner discharge flow path, and the inner discharge flow path and the outer discharge flow path are in a state where the pressure receiving head is separated from the stopper surface. The air in the pressure chamber is guided to the atmospheric pressure port via the. The exhaust valve according to the present invention is characterized in that the pressure receiving head has a tapered surface whose outer diameter increases from one end side where the valve body is provided toward the other end side. In the exhaust valve of the present invention, a gap between the outermost peripheral surface of the pressure receiving head and the accommodation hole is 0.2 to 0.5 mm.

  According to the present invention, the shuttle provided with the valve body for opening and closing the primary side port is provided with the large-diameter pressure receiving head, and the shuttle body is provided with compressed air flowing from the primary side port into the pressure chamber. The thrust in the direction away from the valve seat is applied, and this thrust does not rapidly decrease the pressure in the pressure chamber, so the valve body repeats opening and closing operations until the pressure in the primary port drops below the specified value. Not open. Since the valve body is prevented from opening and closing the primary side port, the occurrence of a noise phenomenon due to the opening and closing operation of the valve body is prevented. As a result, an exhaust valve that quietly relieves air is obtained, and the frequent opening / closing operation of the valve body is prevented, so that the durability of the exhaust valve can be improved.

It is a pneumatic circuit diagram showing an example of a control device of a pneumatic equipment provided with an exhaust valve according to an embodiment of the present invention. It is sectional drawing which shows the exhaust valve shown by FIG. (A) is sectional drawing which shows the exhaust valve in the state from which the valve body left | separated from the valve seat, (B) is sectional drawing which shows the exhaust valve in the state in which the valve body was in the open limit position. FIG. 4 is a partially enlarged cross-sectional view of FIG. It is sectional drawing which shows the exhaust valve which is other embodiment of this invention. It is sectional drawing which shows the conventional exhaust valve as a comparative example. It is an operation characteristic diagram which shows the operation characteristic of the exhaust valve of the present invention compared with the exhaust valve of a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. A pneumatic cylinder 10 as a pneumatic device shown in FIG. 1 has a cylinder tube 12 in which a piston 11 is incorporated so as to reciprocate in an axial direction, and a piston rod 13 attached to the piston 11 is a tip of the cylinder tube 12. It protrudes from the part. The cylinder chamber in the cylinder tube 12 is partitioned by the piston 11 into a forward pressure chamber 14a and a backward pressure chamber 14b. When compressed air is supplied to the forward pressure chamber 14a, the piston rod 13 moves forward in a direction protruding from the cylinder tube 12, and when compressed air is supplied to the backward pressure chamber 14b, the piston rod 13 enters the cylinder tube 12. Move backward in the direction.

  A pneumatic cylinder 10 shown in FIG. 1 is attached to a train body and used to open and close the train door. The piston rod 13 is opened when the piston rod 13 moves forward, and the door is closed when the piston rod 13 moves backward. . In order to synchronize and move the two doors by linear reciprocation of the piston rod 13, the piston rod 13 is connected to the door via an interlocking mechanism (not shown). A forward flow path 15a is connected to the forward pressure chamber 14a, and a backward flow path 15b is connected to the backward pressure chamber 14b. The supply flow path 17 connected to the air pressure source 16 is connected to the forward flow path 15b. An opening / closing valve 18 is provided in the supply flow path 17 in order to switch between a state of communication with the passage 15a and a state of communication with the retreating flow path 15b.

  The on-off valve 18 is an electromagnetic valve having a coil, and when electric power is supplied to the coil, the on-off valve 18 is in a position where the supply passage 17 is communicated with the advance passage 15a. Thereby, the piston rod 13 moves forward and the door is opened. On the other hand, when the power supply to the coil is released, as shown in FIG. 1, the on-off valve 18 is in a position where the supply flow path 17 communicates with the retreat flow path 15b. Thereby, the piston rod 13 moves backward and the door is closed. A muffler 20 for silencing is provided in the exhaust passage 19 that guides the air discharged from the forward pressure chamber 14a and the reverse pressure chamber 14b to the outside.

  A pressure for switching the pressure of the compressed air supplied to the backward pressure chamber 14b to the same pressure as the pressure supplied to the forward pressure chamber 14a and a pressure lower than the pressure in the backward passage 15b. A switching valve 21 is provided, and this pressure switching valve is also called a pressure weakening valve. The pressure switching valve 21 is also an electromagnetic valve having a coil. When power is supplied to the coil, the pressure switching valve 21 is in a position where the retreating flow path 15b communicates with the exhaust flow path 22. Thereby, the pressure of the compressed air supplied to the backward pressure chamber 14b is set to a pressure lower than the pressure supplied to the forward pressure chamber 14a. On the other hand, when the power supply to the coil is released, the pressure switching valve 21 is in a position where the supply flow path 17 communicates with the retreating flow path 15b via the on-off valve 18, as shown in FIG. Thus, the air having the same pressure as the compressed air supplied to the forward pressure chamber 14a is supplied to the backward pressure chamber 14b without the backward passage 15b communicating with the exhaust passage 22. .

  The exhaust flow path 22 is provided with an exhaust valve 23. When power is supplied to the coil of the pressure switching valve 21, the supply flow path 17 communicates with the exhaust flow path 22 and the retreat flow path 15b. The air that has flowed into the exhaust valve 23 from the primary port 24 of the exhaust valve 23 is discharged to the outside of the exhaust valve 23 from the atmospheric release port, that is, the atmospheric pressure port 25, and is supplied from the supply flow path 17 to the retreat pressure chamber 14b. The pressure of the compressed air is reduced by the exhaust valve 23. The air discharged from the exhaust valve 23 is exhausted to the outside through the muffler 26 for silencing.

  As shown in FIGS. 2 and 3, the exhaust valve 23 has a valve housing, that is, a casing 31 in which a primary port 24 is provided at one end, and an atmospheric pressure port is provided at the other end of the casing 31. 25 is provided. The primary side port 24 and the atmospheric pressure port 25 are formed in the casing 31 in a concentric state while communicating with each other via a receiving hole 32 formed in the casing 31. A shuttle 33 is incorporated in the housing hole 32 of the housing 31 so as to reciprocate in the axial direction, and a poppet type rubber valve element 34 is provided at one end of the shuttle 33. The valve body 34 is in close contact with the valve seat 35 provided in the primary port 24, closes the primary port 24, away from the valve seat 35, and connects the primary port 24 to the atmospheric pressure via the accommodation hole 32. It opens and closes between the position where the port 25 is opened.

  The shuttle 33 has a pressure receiving head 33a on the primary port 24 side, that is, one end side, and a main body portion 33b on the opposite side, that is, the other end side. A cylindrical holder 36 is disposed on the atmospheric pressure port 25 side, that is, the other end side of the casing 31. The holder 36 is a male screw that is screwed to a female screw 37 formed on the other end side of the casing 31. 38 is formed, and the holder 36 is screwed to the housing 31. One end surface of the holder 36 serves as a stopper surface 39 with which the pressure receiving head 33a of the shuttle 33 abuts. The stopper surface 39 restricts the opening limit position where the valve element 34 is farthest from the valve seat 35. The holder 36 is formed with a guide hole 40 into which the main body 33 b of the shuttle 33 enters, and the end wall 41 provided at the other end of the holder 36 is formed with a plurality of communication holes 42. The primary side port 24 and the atmospheric pressure port 25 communicate with each other through the communication hole 42.

  A guide rod 43 is attached to the central portion of the shuttle 33 in the radial direction. A valve element 34 is fixed to one end portion of the guide rod 43, that is, a portion protruding from one end surface of the shuttle 33, and the other end portion is a holder 36. The guide hole 44 formed in the end wall portion 41 is supported so as to be slidable in the axial direction. A spring accommodating hole 45 is formed at the other end of the shuttle 33, and a compression coil spring 46 whose both ends abut against the bottom surface of the spring accommodating hole 45 and the end wall 41 of the holder 36 is incorporated in the spring accommodating hole 45. ing. In this way, a spring force in a direction toward the valve seat 35 is applied to the shuttle 33 and the valve body 34 by the compression coil spring 46 as a spring member held in the holder 36.

  A pressure receiving head 33 a provided at one end of the shuttle 33 has a larger diameter than the main body 33 b, and a pressure chamber 47 is formed at one end of the accommodation hole 32. The pressure chamber 47 is an air flow path formed between the valve body 34 and the valve seat 35 when the pressure receiving head 33a of the shuttle 33 abuts against the stopper surface 39 and the valve body 34 reaches the open limit position. The cross-sectional area is larger than the cross-sectional area. Accordingly, when the valve body 34 is separated from the valve seat 35 against the spring force by the pressure of the primary port 24 from the state in which the valve body 34 is in close contact with the valve seat 35, the pressure receiving pressure is larger than the above-described cross-sectional area of the air flow path. A large thrust is applied to the valve body 34 and the shuttle 33 in the direction away from the primary port 24 by the pressure applied to the pressure receiving head 33a having an area.

  Thus, the thrust in the direction of separating the valve body 34 from the valve seat 35 due to the pressure of the primary port 24 is larger than the pressing force of the valve body 34 against the valve seat 35 set by the compression coil spring 46 as the spring member. Thus, when the valve body 34 is separated from the valve seat 35, the pressure of the primary side port 24 enters the pressure chamber 47. When the pressure of the compressed air that has entered the pressure chamber 47 is applied to the pressure receiving head 33a of the shuttle 33, a thrust force that keeps the valve element 34 open against the spring force is applied to the shuttle 33 due to the pressure in the pressure chamber 47. Will be. Since the pressure receiving head 33a has a large pressure receiving area, the valve body 34 is directed toward the valve seat 35 and the primary side port 24 is more than the pressure of the primary port 24 when the valve body 34 is separated from the valve seat 35. The pressure at the time of closing becomes a small value. That is, when the valve body 34 is opened and closed, the valve body 34 comes into close contact with the valve seat 35 when the pressure becomes lower than the pressure of the primary port 24 when the valve body 34 moves away from the valve seat 35. Has hysteresis between open and closed.

  The pressure receiving head 33a of the shuttle 33 is formed with a tapered surface 48 having an outer diameter that increases from one end to the other end. A cylindrical portion 49 is formed at the base end of the pressure receiving head 33a. Is provided. A communication hole 51 having a diameter larger than that of the guide rod 43 is formed in the pressure receiving head 33a, and a plurality of exhaust inflow ports 52 for communicating the communication hole 51 and the pressure chamber 47 are formed in the radial direction. Between the guide rod 43 and the communication hole 51, an inner discharge flow channel 53 that connects the pressure chamber 47 and the atmospheric pressure port 25 through the exhaust inlet 52 is formed. On the other hand, an outer discharge channel 54 that connects the pressure chamber 47 and the atmospheric pressure port 25 is formed between the guide hole 40 of the holder 36 and the outer peripheral surface of the main body 33 b of the shuttle 33. The total cross-sectional area of the inner discharge channel 53 and the outer discharge channel 54 is set to be smaller than the cross-sectional area of the pressure chamber 47, and the air flowing from the pressure chamber 47 to the atmospheric pressure port 25 is discharged to the inner side. It is throttled by the flow path 53 and the outer discharge flow path 54 and discharged to the atmospheric pressure port 25.

  As shown in FIG. 4, the gap R0 between the cylindrical portion 49 that forms the outermost peripheral surface of the pressure receiving head 33a and the accommodation hole 32 is set to 0.4 mm, and the inner discharge channel 53 and the outer side The clearances R1 and R2 of the discharge channel 54 are set to 0.2 mm, respectively. In this way, by setting the gaps R1 and R2 between the inner discharge passage 53 and the outer discharge passage 54 as the throttle passages to be smaller than the gap R0 between the pressure receiving head 33a and the accommodation hole 32, respectively. A flow resistance is applied to the air from the pressure chamber 47 toward the atmospheric pressure port 25.

  FIG. 2 shows a state in which the valve body 34 is in close contact with the valve seat 35 and the primary port 24 is closed. When the pressure of the compressed air at the primary port 24 is equal to or lower than a predetermined pressure, a compression coil spring is shown. Due to the spring force of 46, the valve body 34 comes into close contact with the valve seat 35 and the primary port 24 is closed. For example, when the exhaust valve 23 is used in the pneumatic circuit shown in FIG. 1 and the power supply to the coils of the on-off valve 18 and the pressure switching valve 21 is stopped, the reverse flow as shown in FIG. Compressed air is supplied to the retreat pressure chamber 14b through the passage 15b, but since the compressed air is not supplied to the primary side port 24 of the exhaust valve 23, the primary side port 24 of the exhaust valve 23 is a valve body. 34 is closed.

  In this state, when the coil of the pressure switching valve 21 is energized, the compressed air is supplied to the primary port 24 of the exhaust valve 23 via the on-off valve 18. The primary port 24 is opened away from the seat 35, and the compressed air from the air pressure source 16 flows into the pressure chamber 47. When compressed air flows into the pressure chamber 47, the pressure chamber 47 communicates with the atmospheric pressure port 25 through the inner discharge channel 53 and the outer discharge channel 54. Since the air that has flowed into the pressure chamber 47 is throttled by the inner discharge channel 53 and the outer discharge channel 54, the air that has flowed into the pressure chamber 47 causes the valve element 34 to move the shuttle 33 to the stopper surface 39. It will move to the open limit position where it abuts. When the shuttle 33 moves to the open limit position, the shuttle 33 comes into contact with the stopper surface 39, so the outer discharge channel 54 is closed, and the compressed air in the pressure chamber 47 enters the atmospheric pressure port 25 only through the inner discharge channel 53. Guided.

  In the state of the intermediate position in the process of moving the valve body 34 to the open limit position as shown in FIG. 3B, as shown in FIG. 3A, the pressure chamber 47 has the inner discharge flow path 53 and the outer discharge flow. Since it communicates with the atmospheric pressure port 25 via the passage 54, the compressed air quickly flows toward the atmospheric pressure port 25 from both flow paths. As a result, the pressure of the primary side port 24 quickly reaches the set value, and the shuttle 33 receives a centering action by the air flowing through the respective discharge passages to prevent vibration in the radial direction. When the valve body 34 moves to the open limit position, the outer discharge channel 54 is closed, so that the air in the pressure chamber 47 is discharged to the atmospheric pressure port 25 only through the inner discharge channel 53. Also at this time, the shuttle 33 receives a centering action by the air flowing into the inner discharge passage 53 from the exhaust inlet 52 and flowing therethrough, thereby preventing the occurrence of vibrations.

  When the valve body 34 opens and moves to the open limit position, the primary side port 24 and the atmospheric pressure port 25 are coaxially provided in the housing 31, so that the primary side port 24 and the atmospheric pressure port 25 are provided. The flow of the compressed air toward the center does not bend greatly in the casing 31 and flows in the casing 31 as a whole in a stable manner in the axial direction. There is no vibration. Moreover, even if the valve body 34 is opened, a discharge flow path as a throttle flow path is formed between the pressure chamber 47 and the atmospheric pressure port 25, so that the compressed air that has flowed into the pressure chamber 47 suddenly flows. Once the valve body 34 is opened, the valve body 34 returns toward the valve seat 35 until the pressure of the primary side port 24 is reduced to a pressure lower than the set pressure. Is prevented. As a result, in combination with the formation of a stable flow of compressed air in the casing 31, the valve body 34 is moved to the valve seat 35 until the pressure of the primary port 24 drops below the set value. The occurrence of vibration in the axial direction due to the frequent opening and closing operation of the primary side port 24 is prevented. Therefore, when the compressed air is discharged to the atmospheric pressure port 25, there is no occurrence of a noise phenomenon due to the vibration of the valve body 34, and the exhaust valve operates silently.

  When the pressure of the primary side port 24 falls below a set value, the valve element 34 is closed toward the valve seat 35 by the spring force of the compression coil spring 46. In this process, the shuttle 33 is stopped. When separated from the surface 39, the outer discharge channel 54 is opened in addition to the inner discharge channel 53, so that the pressure in the pressure chamber 47 is prevented from increasing, and the valve element 34 closes the valve seat 35. In this case, the primary side port 24 is reliably closed without causing the return operation, and it is possible to prevent the sounding phenomenon from occurring even during the closing operation.

  FIG. 5 is a cross-sectional view showing an exhaust valve 23 according to another embodiment of the present invention. In FIG. 5, the same members as those in the exhaust valve 23 shown in FIG. . In the exhaust valve 23, the pressure receiving head 33a is not provided with the exhaust inlet 52 described above, and the inner exhaust passage 53 is not provided. In the exhaust valve 23, a communication discharge channel 55 is formed between one end of the holder 36 and the accommodation hole 32, and the communication discharge channel 55 is connected to the outer discharge channel 54 via the communication hole 56. Communicating with Therefore, when the valve element 34 is separated from the valve seat 35, the exhaust valve 23 causes the compressed air that has flowed into the pressure chamber 47 until the shuttle 33 comes into contact with the stopper surface 39 to communicate with the communication discharge channel 55. 56 flows into the outer discharge flow path 54 through 56, and flows into the outer discharge flow path 54 through a gap between the pressure receiving head 33 a of the shuttle 33 and the stopper surface 39. On the other hand, when the shuttle 33 comes into contact with the stopper surface 39, the gap between the pressure receiving head 33 a of the shuttle 33 and the stopper surface 39 is closed, so that the compressed air in the pressure chamber 47 communicates with the communication discharge channel 55. It flows to the outer discharge channel 54 only through the hole 56. Also in the exhaust valve 23 shown in FIG. 5, the function similar to the exhaust valve 23 shown in FIG. 2 is acquired.

  FIG. 6 is a cross-sectional view showing a conventional exhaust valve 23a as a comparative example. An atmospheric pressure port 25 is formed in the casing 31 of the exhaust valve 23a so as to face a direction perpendicular to the primary side port 24. The housing 31 has a plug mounting hole 61 formed coaxially with the primary port 24 so as to face the primary port 24, and a spring mounting plug 62 is screwed into the plug mounting hole 61. Yes. A compression coil spring 46 is mounted between the spring mounting plug 62 and the valve body 34 in order to apply a spring force in the direction toward the valve seat 35 to the valve body 34. One end of the compression coil spring 46 is in contact with a metal ring 63 attached to the valve body 34, and the other end is in contact with a flange portion of the spring mounting plug 62.

  FIG. 7 is a characteristic diagram showing the operating characteristics of the exhaust valve 23 of the present invention in comparison with the exhaust valve 23a of the comparative example. In FIG. 7, the solid line indicates the operating characteristics of the exhaust valve 23 shown in FIG. 2, and the two-dot chain line indicates the operating characteristics of the exhaust valve 23a of the comparative example shown in FIG.

  In the conventional exhaust valve 23a shown in FIG. 6, when supply pressure is applied to the primary side port 24, the valve body 34 vibrates until the pressure of the primary side port 24 reaches the set pressure, that is, the relief pressure. Had occurred. This is because when the valve body 34 is separated from the valve seat 35 and the pressure of the primary port 24 is released, the valve body 34 resonates due to the pulsating flow of compressed air flowing through the exhaust valve 23a and the spring force. It is believed that there is. Due to this resonance phenomenon, the valve element 34 opens and closes the primary port 24 in small increments, and a reduction in exhaust efficiency is inevitable.

  On the other hand, the exhaust valve 23 of the present invention can be reduced to the relief pressure in a time earlier than the exhaust valve 23a of the comparative example, and no resonance phenomenon occurred. The reason is that the shuttle 33 is provided with a large pressure receiving head 33a, and the pressure is reduced at a time until the pressure of the primary side port 24 becomes lower than the relief pressure. This is considered to be because hysteresis is set in the operating pressure at the time of opening and closing so that the valve body 34 is closed when the pressure becomes lower than the pressure at the time of opening the port 24. Thus, by providing hysteresis, the valve body 34 does not vibrate so as to open and close the primary side port 24, and the exhaust valve 23 does not generate a noise phenomenon at the time of relief. became.

  In the exhaust valve 23 of the present invention, the gap R0 between the cylindrical portion 49 of the pressure receiving head 33a, that is, the outermost peripheral surface of the pressure receiving head 33a, and the accommodation hole 32 is set to 0.4 mm. Since the clearance between the valve body 34 and the accommodation hole 32 in the exhaust valve 23a shown in FIG. 6 is set to 0.2 mm, the valve body 34 moves to the inner periphery of the accommodation hole 32 as the exhaust valve 23a operates. The outer peripheral surface of the valve body 34 was worn in contact with the surface, and the durability was limited. In contrast, the exhaust valve shown in FIG. 2 is provided with an inner discharge passage 53 and an outer discharge passage 54, and the exhaust valve 23 shown in FIG. 5 is provided with an outer discharge passage 54. Since the air flowing toward the atmospheric pressure port 25 is throttled through these discharge passages, the gap R0 between the outermost peripheral surface of the shuttle 33 and the accommodation hole 32 is made larger than the exhaust valve 23a of the comparative example. In addition, even if wear is generated on the outer peripheral surface of the shuttle 33 with a small setting, the operating characteristics of the exhaust valve are not changed by long-term use of the exhaust valve. Thereby, even if the clearance R0 was set to 0.1 to 0.5 mm, the durability of the exhaust valve could be improved.

  The operation of the pneumatic cylinder 10 when the above-described exhaust valve 23 is used in the pneumatic circuit shown in FIG. 1 will be described. When the door is opened, power is supplied to the coil of the on-off valve 18 so that the supply flow path 17 communicates with the forward flow path 15a, and compressed air is supplied to the forward pressure chamber 14a. Move forward in the direction to project. At this time, the air in the retreat pressure chamber 14 b is guided to the exhaust passage 19 via the pressure switching valve 21 and the on-off valve 18.

  On the other hand, when closing the door, power supply to the coil of the on-off valve 18 is stopped and power is supplied to the coil of the pressure switching valve 21. As a result, the supply flow path 17 communicates with the retreat flow path 15b via the on-off valve 18 and also communicates with the primary port 24 of the exhaust valve 23, and the retreat pressure chamber 14b is supplied to the advance pressure chamber 14a. Compressed air adjusted to a pressure lower than the pressure is supplied. Therefore, when closing the train door, the door is closed with a weaker closing force than when opening the door, and even if the passenger's baggage and clothes of the train are caught in the door, it is caught You can easily pull in your baggage. When the power supply to the coil of the pressure switching valve 21 is stopped after the door is almost closed, the compressed air supplied from the supply flow path 17 is supplied to the retreat pressure chamber 14b without being depressurized. Therefore, the door is kept closed with a strong force. In the case shown in FIG. 1, the piston rod 13 is moved forward to open the door and moved backward to close the door, but the door opening and closing operation and the reciprocating direction of the piston rod 13 are reversed. You may make it let it.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the case where the exhaust valve 23 is used in the pneumatic circuit shown in FIG. 1 has been described. However, if the exhaust valve 23 is for reducing the compressed air supplied to the primary side port 24, as shown in FIG. In addition to the operation control of the pneumatic cylinder 10, it can be used for various purposes.

DESCRIPTION OF SYMBOLS 10 Pneumatic cylinder 11 Piston 12 Cylinder tube 13 Piston rod 18 On-off valve 21 Pressure switching valve 24 Primary side port 25 Atmospheric pressure port 31 Housing | casing 32 Accommodating hole 33 Shuttle 33a Pressure receiving head 33b Main body part 34 Valve body 35 Valve seat 36 Holder 39 Stopper surface 40 Guide hole 41 End wall portion 42 Communication hole 43 Guide rod 44 Guide hole 46 Compression coil spring (spring member)
47 Pressure chamber 48 Tapered surface 49 Cylindrical portion 51 Communication hole 52 Exhaust inflow port 53 Inner discharge flow channel 54 Outer discharge flow channel 55 Communication discharge channel 56 Communication hole

Claims (6)

The valve body is brought into close contact with the valve seat provided in the primary port by a spring force to close the primary port, and the valve body is separated from the valve seat when the pressure of the primary port is equal to or higher than a predetermined pressure. An exhaust valve that adjusts the pressure of the primary port by opening the gas of the primary port to the atmospheric pressure port,
An accommodation hole is formed to communicate the primary side port provided at one end with the atmospheric pressure port provided at the other end, and the valve body is reciprocated in the axial direction with the shuttle provided at one end. A housing for free storage;
A pressure chamber provided at one end of the shuttle and having a cross-sectional area larger than a cross-sectional area of an air flow path formed between the valve body and the valve seat when the valve body is separated from the valve seat. A pressure receiving head that forms between the accommodation hole and the shuttle;
A holder that is provided in the housing and holds a spring member that applies a spring force toward the valve seat with respect to the valve body and is formed with a guide hole into which the other end of the shuttle enters;
An exhaust valve having a cross-sectional area that is narrower than a cross-sectional area of the pressure chamber, and a discharge passage that restricts air flowing in an axial direction from the pressure chamber toward the atmospheric pressure port.   2. The exhaust valve according to claim 1, wherein the exhaust passage is formed between the guide hole of the holder and an outer peripheral surface of the other end of the shuttle.   2. The exhaust valve according to claim 1, wherein the exhaust valve communicates with an outer discharge passage formed between the guide hole of the holder and an outer peripheral surface of the other end of the shuttle, and an exhaust inlet formed in the pressure receiving head. Then, the exhaust flow path is formed by an inner discharge flow path formed in the shuttle.   The exhaust valve according to claim 3, wherein a stopper surface is provided on the holder to contact the pressure receiving head to regulate an open limit position of the valve body, and the pressure receiving head is in contact with the stopper surface. The air in the pressure chamber is guided to the atmospheric pressure port through the inner discharge flow path, and the inner discharge flow path and the outer discharge flow are in a state where the pressure receiving head is separated from the stopper surface. An exhaust valve for guiding the air in the pressure chamber to the atmospheric pressure port through a passage.   5. The exhaust valve according to claim 1, wherein the pressure-receiving head has a tapered surface whose outer diameter increases from one end side to the other end side where the valve body is provided. An exhaust valve characterized by.   The exhaust valve according to any one of claims 1 to 5, wherein a gap between an outermost peripheral surface of the pressure receiving head and the accommodation hole is 0.2 to 0.5 mm. Exhaust valve.

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