TW202238018A - Selector valve - Google Patents

Abstract

To provide a selector valve which can control a flow rate gradually and prevent a delay from occurring in a flow rate switch point when an operation is resumed after use stop. A selector valve 1 includes a main valve 50 which may move in a sleeve 10 and is provided with: a first passage 31 and a first on-off valve 41 which allow a pilot supply port 26 and an open port 28 to communicate with each other; a second passage 32 and a second on-off valve 42 which allow a supply port 20 and the open port 28 to communicate with each other; a third passage 33 and a third on-off valve 43 which allow the supply port 20 and a first exhaust port 22 to communicate with each other; and a fourth passage 34 which allows the supply port 20 and a second exhaust port 24 to communicate with each other. In the first on-off valve 41 and the second on-off valve 42, a valve body and a valve seat contact with each other or separate from each other in a moving direction of the main valve 50. When pilot supply air is larger than a predetermined pressure, the first on-off valve 41 and the second on-off valve 42 are closed and the third on-off valve 43 is opened. When the pilot supply air is smaller than the predetermined pressure, the first on-off valve 41 and the second on-off valve 42 are opened and the third on-off valve 43 is closed.

Description

switching valve

This invention relates to switching valves for air compression.

Devices using air cylinders are often used in automatic equipment production lines for assembling mechanical devices, electronic devices, and the like. However, if the moving speed of the piston in the cylinder is increased, the cycle time can be shortened, but on the contrary, the shock at the time of stopping becomes large, which shortens the life of the cylinder.

In the past, there is generally the following method: a shock absorber (such as an oil type) is installed in the mechanism part connected to the piston of the air cylinder to alleviate the impact when the air cylinder (piston) stops, so that even if the moving speed of the piston of the air cylinder is increased, the air will not stop. The impact of time will not increase.

Alternatively, a technology related to a cylinder with a cushioning mechanism that alleviates the shock at the time of stopping is also disclosed by providing a shock-relieving cushioning mechanism in the cylinder itself (refer to Patent Document 1: Japanese Patent Application Laid-Open No. 2003-254303). [Prior Art Literature] [Patent Document]

Patent Document 1: Japanese Patent Laid-Open No. 2003-254303 Patent Document 2: Japanese Patent Laid-Open No. 2014-055631

However, for example, in the case of a structure in which a shock absorber is provided to relieve the shock when the piston of the cylinder stops, since the shock absorber needs to be assembled into the device, there are problems such as complicated mechanism, component cost, and assembly cost increase. .

In order to solve this problem, the inventors of the present application have developed a speed controller with a buffer function, which can control the machine assembled to the external air compressor in stages with a simple structure without using a shock absorber. The moving speed in a single stroke of the cylinder (piston) (refer to Patent Document 2: Japanese Patent Laid-Open No. 2014-055631).

Here, in the case of using a speed controller with a buffer function to control the moving speed in a single stroke of the cylinder (piston) of the external air compressor in stages, it is important to make the switching point of the gas flow rate by passing The switching point of the specified speed is stable. The reason is that, for example, if the switching point of the speed is delayed, the buffer cannot perform its function and a huge impact will be generated until the stroke end of the cylinder (piston).

After careful study, the inventors of the present application found that in the conventional speed controller with a buffer function, the problem that the main valve or the equivalent The components of the main valve are stuck, and the switching point of the flow rate, that is, the speed switching point may be delayed at the first stroke after restart.

[Problem to be solved by the invention]

The present invention is made in view of the above circumstances, and its object is to provide a switching valve configured to be used in connection with an external air compressor, which can control the flow rate of the passing gas in stages, and can prevent the flow rate of the gas passing through after stopping for a certain period of time. When restarting, a delay is introduced at the switching point of the flow.

As one embodiment, the above-mentioned problems are solved by means of solutions disclosed below.

A switching valve is disclosed, characterized by, It includes: a sleeve having a cylindrical shape and having a supply port opening to connect the inside and the outside, a first exhaust port, a second exhaust port, a guide supply port, and an open port; and a main valve arranged to be movable along the axial direction within the aforementioned sleeve, A first flow path for connecting the guiding supply port with the open port, a second flow path for connecting the supply port with the open port, and a flow path for connecting the supply port to the first exhaust port are provided to pass through the sleeve. port, and a fourth flow path that connects the supply port with the second exhaust port, and is provided with a first on-off valve for opening and closing the first flow path, and a valve for opening and closing the second flow path. The second on-off valve, the third on-off valve that opens and closes the aforementioned third flow path; The cylinder is integrated or separately installed, and the other is integrated or separately installed with the aforementioned main valve; in the aforementioned first on-off valve and the aforementioned second on-off valve, the aforementioned valve body and the aforementioned valve seat are configured to be in contact with the aforementioned main valve. When the pressure of the pilot supply air supplied to the pilot supply port is higher than a predetermined pressure, the main valve is in a state of moving toward the first end side in the sleeve, and the The first on-off valve and the second on-off valve are closed, and the third on-off valve is opened; and when the pressure of the pilot supply air supplied to the pilot supply port is lower than a predetermined pressure, the main valve is turned on. In a state in which the sleeve moves toward the second end portion, the first on-off valve and the second on-off valve are opened, and the third on-off valve is closed. [Effect of Invention]

According to the switching valve disclosed, when used in connection with an external air compressor, the flow rate of passing gas can be controlled in stages. Furthermore, it is possible to prevent a delay at the switching point of the flow rate when the use is restarted after being stopped for a certain period of time.

[Mode for Carrying Out the Invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 are front cross-sectional views (schematic views) showing a structural example of the switching valve 1 according to the present embodiment, and are also used as operation explanatory views. In addition, in all the drawings for explaining the embodiments, members having the same functions are given the same reference numerals, and repeated description thereof may be omitted.

As an example, the switching valve 1 of this embodiment is assumed to be used in such a way that it is disposed (connected) to the exhaust gas (discharged by the movement of the piston) of a reciprocating cylinder (hereinafter, simply referred to as "cylinder") C. Compressed air with a predetermined pressure) flows through the flow path, and the operating speed of the cylinder C is controlled in stages (for example, in two stages of high speed and low speed). External air compressor.

As shown in FIGS. 1 to 3 , the switching valve 1 is configured by including a main valve 50 disposed in a cylindrical (as an example, substantially cylindrical) sleeve 10 so as to be able to move along the axial direction ( Moving in the direction of the central axis S), the sleeve 10 has a space portion at the center in the radial direction. In addition, as the constituent material of the switching valve 1, a resin material (such as POM, PBT, etc.), a metal material (such as , stainless steel alloy, aluminum alloy, brass, etc.).

The sleeve 10 of this embodiment is constituted by a cylindrical (as an example, substantially cylindrical) first guide sleeve 14 and a cylindrical (as an example, substantially cylindrical) second guide sleeve 16, respectively. Through sealing members 18A, 18B, and 18C (for example, O-rings made of rubber, elastomer, etc.) fitted into the inner cylinder portion of the cylindrical (for example, approximately cylindrical) main sleeve 12, The first guide bush 14 has a space in the radial center, the second guide bush 16 has a space in the radial center, and the main sleeve 12 has a space in the radial center. Therefore, the main valve 50 that moves in the axial direction in the sleeve 10 is more specifically configured to move in the axial direction in the first guide sleeve 14 and the second guide sleeve 16 (that is, in the respective spaces). . However, the structure of the sleeve 10 is not limited to the above, and as a modified example, the sleeve 10 may be integrally formed, and the first guide sleeve 14 and the second guide sleeve 16 may be integrally formed, etc. not shown).

In this sleeve 10, there is provided a method to communicate the inside and outside of the cylindrical part (that is, to communicate the inside and outside in the whole of the fitted main sleeve 12, first guide sleeve 14, and second guide sleeve 16). ) form the port below the opening. Specifically, a supply port 20 , a first exhaust port 22 , a second exhaust port 24 , a guide supply port 26 , and an open port 28 are provided.

In addition, each of these ports is provided with the following flow passages configured to pass between the inner cylinder portion of the sleeve 10 and the outer peripheral portion of the main valve 50 (shown in FIG. ). Specifically, a first flow path 31 for connecting the guide supply port 26 to the open port 28, a second flow path 32 for connecting the supply port 20 to the open port 28, and a second flow path 32 for connecting the supply port 20 to the first exhaust port 22 are provided. The third flow path 33 and the fourth flow path 34 connecting the supply port 20 and the second exhaust port 24 .

Moreover, a first on-off valve 41 for opening and closing the first flow path 31, a second on-off valve 42 for opening and closing the second flow path 32, and a third on-off valve 43 for opening and closing the third flow path 33 are provided (in order to avoid distortion of the figure). It is complicated and shown in Fig. 2 and Fig. 3).

As for the above-mentioned first on-off valve 41, the valve body 41a formed separately using rubber, elastic body, etc. is provided on the main valve 50, and the valve seat 41b is connected to the sleeve 10 (in this embodiment, the first guide sleeve). 14) It is set in one piece (also can be formed separately). In addition, as a modified example, a configuration in which the valve body 41 a is arranged on the sleeve 10 and the valve seat 41 b is arranged on the main valve 50 is also conceivable (not shown).

Similarly, for the second on-off valve 42, the valve body 42a formed separately using rubber, elastic body, etc. is provided on the main valve 50, and the valve seat 42b is connected to the sleeve 10 (in this embodiment, the first valve body). The guide sleeve 14) is provided in one piece (also can be formed separately). In addition, as a modified example, a configuration in which the valve body 42 a is arranged on the sleeve 10 and the valve seat 42 b is arranged on the main valve 50 is also conceivable (not shown). In addition, in the third on-off valve 43, the valve body 43a formed separately using rubber, elastic body, etc. is provided on the main valve 50, and the valve seat 43b is connected to the sleeve 10 (in this embodiment, the first guide sleeve). 14) It is set in one piece (also can be formed separately). In addition, as a modified example, a configuration in which the valve body 43 a is arranged on the sleeve 10 and the valve seat 43 b is arranged on the main valve 50 is also conceivable (not shown).

In addition, in this embodiment, a structure is adopted in which the valve body 41a of the first on-off valve 41 and the valve body 42a of the second on-off valve 42 are provided on a gasket member 40 of an integral structure, and the gasket member 40 is embedded in the The outer peripheral portion of the main valve 50 . According to this, the number of parts can be reduced and the cost can be reduced. However, it is not limited to this structure, The valve body 41a and the valve body 42a may be comprised separately (not shown).

Here, gas at a predetermined pressure (compressed air of about 0.5 MPa as an example) is supplied (input) to the pilot supply port 26 as "pilot supply air". On the other hand, gas of a predetermined pressure (compressed air of about 0.5 MPa as an example) is supplied (input) to the supply port 20 as "supply air". Each gas (compressed air) can be supplied from a common supply source (for example, a compression pump etc.), for example, and can adopt the structure (not shown). However, it is not limited to this, and it is also possible to adopt a configuration (not shown) that supplies from respective supply sources (compression pumps, etc., as an example).

The switching valve 1 having such a structure operates as follows. Specifically, when the pressure of the pilot supply air supplied to the pilot supply port 26 is higher than a predetermined pressure (hereinafter, referred to as “first set pressure”), the main valve 50 is turned toward the first end portion in the sleeve 10 . (the right end in the figure) 10a side moves state (the state shown in Fig. 1), the first on-off valve 41 and the second on-off valve 42 are set to "close", and the third on-off valve 43 is set to "open". ". On the other hand, when the pressure of the pilot supply air supplied to the pilot supply port 26 is lower than the predetermined pressure (the first set pressure), the main valve 50 is moved toward the second end portion (the left end portion in the figure) in the sleeve 10 . ) 10b side moving state (state shown in FIG. 3 ), the first on-off valve 41 and the second on-off valve 42 are "opened", and the third on-off valve 43 is "closed". Note that the state shown in FIG. 2 is in the middle of transition from the state shown in FIG. 1 to the state shown in FIG. 3 , or in the middle of transition from the state shown in FIG. 3 to the state shown in FIG. 1 .

Thereby, as an example, it is possible to switch between a circuit in which the supply air supplied to the supply port 20 is exhausted from both the first exhaust port 22 and the second exhaust port 24 and a circuit in which the air is exhausted only from the second exhaust port 24. to switch. That is, it is possible to switch the exhaust flow path, specifically, switch between the third flow path 33 and the fourth flow path 34 and the fourth flow path 34. Therefore, the cross-sectional area of the flow path (maximum The switching of the narrow part) switches the flow rate of the compressed air passing through. In addition, a throttle valve 62 and a throttle valve 64 (refer to FIG. 4 ) are provided in the third flow path 33 and the fourth flow path 34 , respectively, so that the flow rate of compressed air passing through each flow path can be adjusted.

Here, as an example of use (connection example) of the switching valve 1 of this embodiment, as shown in the circuit diagram of FIG. connected to use. At this time, when compressed air of a predetermined pressure (here, the aforementioned 0.5 MPa, etc.) is supplied to the suction port of the cylinder C to move the piston, compressed air of the same pressure is sent out from the discharge port. The compressed air is supplied (input) to the supply port 20 of the switching valve 1 .

Therefore, by switching the valve 1, it is possible to achieve the effect that the supply air supplied to the supply port 20 can be exhausted from both the first exhaust port 22 and the second exhaust port 24 and only from the second exhaust port. Port 24 exits the loop for switching. That is, it is possible to switch the cross-sectional integration of the flow path for exhausting the external air compressor (cylinder C) in stages (here, two stages). Thereby, the operating speed (axial movement speed) of the piston of the air cylinder C can be switched from high-speed movement to low-speed movement, and a buffer function can be produced. Therefore, the speed before the stop of the piston can be reduced, so that the shock at the time of stop can be alleviated.

Furthermore, as another example, for example, by adopting a structure such as providing an on-off valve (not shown) for opening and closing the fourth flow path 34, it is possible to supply air supplied to the supply port 20 from only the first exhaust port 22. Switching is made between a circuit that is exhausted and a circuit that is exhausted only from the second exhaust port 24 . According to this structure, the same effect as above can be obtained, that is, a buffer function can be produced by switching the flow rate of the compressed air passing through.

However, if the damping function is generated only when the piston of the air cylinder C moves, it can also be realized by a conventional speed controller with a damping function, a spool-type switching valve, etc. as described above. However, in the conventional products, the problem that the internal main valve (or a member equivalent to the main valve) will be fixed when restarting after stopping for a certain period of time, and the first stroke after restarting There may be a delay at the switching point of the flow, that is, the speed switching point. Here, the experimental results using the conventional mechanism are shown in FIG. 5 . Set the time to restart after both stop using. Curve (plot) A1 is the standard data during normal operation, curve A2 is the data when restarting after 10 minutes of stopping use, and curve A3 is the data when restarting after stopping using for 3 hours. In the above-mentioned curves A1-A3, the vertical axis is the pressure value of the pilot supply air, and the horizontal axis is the value of the response delay time when the main valve 50 responds (starts to move) in response to the pressure change of the pilot supply air. It can be seen from the graph that the longer the time of non-use, the longer the delay time for the main valve 50 to respond (start moving point: point E in FIG. 5 ), that is, the greater the degree of fixation of the main valve 50 becomes.

In order to solve the above-mentioned problems, the switching valve 1 of the present embodiment has the following configuration. First, in the first on-off valve 41 and the second on-off valve 42 , the valve body and the valve seat (specifically, the valve body 41 a and the valve seat 41 b and the valve body 42 a and the valve seat 42 b ) are arranged so as to be in contact with the main valve 50 . contact and separation in the direction parallel to the moving direction of the sleeve 10 (that is, the same direction as the central axis S of the inner cylindrical portion of the sleeve 10). It is clear from the studies of the inventors of the present application that the sticking of the subject main valve is caused by the tight contact state caused by the pressure contact between the valve body provided in each on-off valve and the corresponding valve seat. In this regard, according to the above-mentioned structure, even if the valve body (41a, 42a here) is pressed against the corresponding valve seat (41b, 42b here) to form a close contact state, the close contact state is easily eliminated, and can be eliminated (or suppressed). The generation of fixation.

Here, the experimental results using the switching valve 1 of this embodiment having this structure are shown in FIG. 6 . Curve B1 is the standard data during normal operation, and curve B2 is the data when restarting after stopping for 3 hours. In addition, the indexes of the vertical axis and the horizontal axis are the same as those in FIG. 5 . As can be seen from the graph, according to the switching valve 1 of the present embodiment, the degree of fixation of the main valve 50 is almost non-existent (or very small) even if the time of non-use is prolonged.

Furthermore, as a modified example, a structure may also be adopted in which the valve seats 41b, 42b, 43b are formed using metal materials or resin materials, and all or a part of them are placed on the contact surfaces with the corresponding valve bodies 41a, 42a, 43a. , performing plating treatment or grease coating to lower the friction coefficient of the surface. Thereby, even if the valve body (here, 41a, 42a) is press-contacted with the corresponding valve seat (here, 41b, 42b) to form a close contact state, the close contact state is easily eliminated, and the elimination (or suppression) of sticking can be further improved. the resulting effect.

In addition, in the switching valve 1 of the present embodiment, there is a structure characterized in that the second flow path 32 (here, the gap between the inner cylinder portion of the first guide sleeve 14 and the outer peripheral portion of the main valve 50 The minimum cross-sectional area of the narrowest portion) is smaller than the minimum cross-sectional area of the first flow path 31 (here, downstream of the first on-off valve 41 and to the outlet of the open port 28 ). Assuming that the minimum cross-sectional area of the second flow path 32 is greater than or equal to the minimum cross-sectional area of the first flow path 31, the compressed air supplied to the supply port 20 flows into the pilot supply port 26 side when the main valve 50 moves, so that the pilot supply The pressure of the air creates a thrust that rises above the setting. As a result, there arises a problem that the main valve 50 cannot be switched stably at a desired timing.

To solve this problem, in this embodiment, by providing an open port 28 (details will be described later) that guides the exhaust of the supplied air to the atmosphere, and making the minimum cut-off of the second flow path 32 as described above A structure having an area smaller than the minimum cross-sectional area of the first flow path 31 can solve the above problems. That is, according to these structures, when the switching (moving) of the main valve 50 is carried out toward the direction of opening the first on-off valve 41, the guide supply air is released to the atmosphere at one go, and almost no (or extremely small) passing through the first on-off valve 41 can be generated. The function of the secondary channel 32 to flow to the supply port 20 side. Moreover, the supply air that flows from the supply port 20 through the second flow path 32 can be made to flow to the open port 28 side rather than to the guide supply port 26 side, so that almost no (or extremely small) flow of the supply air by the guide can be caused. The thrust generated by the pressure rises above the set action. Therefore, the movement, that is, the switching of the main valve 50 can be stably performed at a desired timing. In addition, the switching timing can be set by the speed controller 66 (see FIG. 4 ).

As described above, in the present embodiment, the open port 28 adopts a structure in which gas is opened and circulated under atmospheric pressure. However, it is not limited to the above-mentioned structure, and the same effects can be obtained even if a structure in which gas is openly circulated under a slight pressure (for example, about 0.2 MPa or less).

In addition, in the switching valve 1 of this embodiment, a biasing member (for example, a coil spring or other spring member) 60 is provided, and the aforementioned biasing member is used to make the main valve 50 move toward the second end in the sleeve 10 . 10b The direction of movement is biased. Thereby, the moving operation of the main valve 50 can be assisted, and the posture of the main valve 50 can be stabilized when no supply air is applied (or when a small amount of supply air is applied). In addition, the biasing force of the biasing member 60 (for example, a coil spring) is appropriately set according to the size of the sleeve 10 and the main valve 50, and is set so that a biasing force of about 1 N is generated during assembly as an example.

When adopting such a structure including the spring 60, the above-mentioned "first set pressure" is set as the pressure of the supply air supplied to the supply port 20 and the biasing force of the biasing member 60 (such as a coil spring) after conversion. The pressure obtained by adding the pressure.

Here, as described above, the configuration is such that the supply air (compressed air) supplied to the supply port 20 and the pilot supply air (compressed air) supplied to the pilot supply port 26 are supplied from a common supply source (in addition, "supply Air" is supplied through cylinder C). Therefore, it is necessary to adjust the pressure of the guide supply air to be higher than the first set pressure.

Regarding this point, in the main valve 50 of the present embodiment, the pressure receiving area of the pilot supply air supplied from the pilot supply port 26 (specifically, the diameter of the valve body 41a (the contact position with the valve seat 41b) The predetermined pressure receiving area) is larger than the pressure receiving area of the supply air supplied from the supply port 20 (specifically, the pressure receiving area defined by the diameter of the valve body 42a (contact position with the valve seat 42b)). According to this structure, the thrust force for moving the main valve 50 toward the first end portion 10 a by the pressure of the guided supply air can be set to be higher than the thrust force for moving the main valve 50 toward the first end portion 10 a by the pressure of the supplied air and the biasing force of the biasing member 60 . The thrust force to move in the direction of the second end portion 10b is large. In addition, as an example, since the supply port 20 is connected to the exhaust port of the cylinder C, the flow velocity of the exhaust gas is high and the pressure of the supply air is low. Therefore, these effects overlap and occur. , The effect of maintaining a high state of the thrust generated by the pressure of the guided supply air is improved.

As described above, according to the switching valve disclosed above, the flow rate when the gas is discharged at a predetermined pressure supplied (input) to the supply port can be controlled in stages (two stages in this case). As an example, if it is configured to be connected to the exhaust port of a cylinder assembled to an external air compressor, the piston of the cylinder can be moved at high speed for a short period of time after starting to move to shorten the operation time, and the piston can The movement speed is switched from high speed to low speed at the set point of time immediately before the stop. Therefore, shock absorption when the piston of the air cylinder stops can be realized without using a shock absorber.

Furthermore, this switching valve can prevent a delay in the switching point of the flow rate due to the main valve being fixed to the sleeve when the use is restarted after stopping for a certain period of time.

In addition, the present invention is not limited to the embodiments described above, and various changes can be made without departing from the scope of the present invention, which needless to say.

1: switch valve 10: Sleeve 10a: first end 10b: second end 12: Main sleeve 14: First guide sleeve 16: Second guide sleeve 18A, 18B, 18C: sealing member 20: supply port 22: The first exhaust port 24: Second exhaust port 26: boot supply port 28: open port 31: The first channel 32: Second flow path 33: The third channel 34: The fourth channel 40: Gasket member 41: The first opening and closing valve 41a: valve body 41b: valve seat 42: Second opening and closing valve 42a: valve body 42b: valve seat 43: The third opening and closing valve 43a: valve body 43b: valve seat 50: Main valve 60: Offset member 62,64: throttle valve 66: Speed controller C: Cylinder S: central axis

Fig. 1 is a schematic diagram showing a structural example of a switching valve according to an embodiment of the present invention and also an operation explanatory diagram. Fig. 2 is a schematic diagram showing a structural example of a switching valve according to an embodiment of the present invention, and also an operation explanatory diagram. Fig. 3 is a schematic diagram showing a structural example of a switching valve according to an embodiment of the present invention and also an operation explanatory diagram. Fig. 4 is a circuit diagram showing an example in which a switching valve according to an embodiment of the present invention is connected to an external air compressor. Fig. 5 is an explanatory diagram (experimental data using a known mechanism) for explaining technical problems to be solved by the switching valve according to the embodiment of the present invention. Fig. 6 is an explanatory diagram for explaining the effect achieved by the switching valve according to the embodiment of the present invention (experimental data using the switching valve according to the embodiment of the present invention).

1: switch valve

10: Sleeve

10a: first end

10b: second end

12: Main sleeve

14: First guide sleeve

16: Second guide sleeve

20: supply port

22: The first exhaust port

24: Second exhaust port

26: boot supply port

28: open port

31: The first channel

32: Second flow path

33: The third channel

34: The fourth channel

40: Gasket member

41: The first opening and closing valve

42: Second opening and closing valve

43: The third opening and closing valve

50: Main valve

60: Offset member

S: central axis

Claims (6)

A switching valve characterized by, have: a sleeve having a cylindrical shape and having a supply port, a first exhaust port, a second exhaust port, a guide supply port, and an open port opening so as to connect the inside and the outside; and a main valve configured to be movable in the axial direction within the aforementioned sleeve, The first flow path that connects the aforementioned guide supply port with the aforementioned open port, the second flow path that connects the aforementioned supply port with the aforementioned open port, and the aforementioned supply port with the aforementioned first exhaust port are set in such a way as to pass through the aforementioned sleeve. The third flow path communicated, and the fourth flow path that communicates the aforementioned supply port with the aforementioned second exhaust port, and is provided with a first on-off valve that opens and closes the aforementioned first flow path, and a second on-off valve that opens and closes the aforementioned second flow path. Two on-off valves, and a third on-off valve that opens or closes the aforementioned third flow path, The aforementioned first on-off valve, the aforementioned second on-off valve, and the aforementioned third on-off valve are all, one of the valve body and the valve seat is integrally or separately provided with the aforementioned sleeve, and the other is integrally or separately provided with the aforementioned main valve. set up, In the first on-off valve and the second on-off valve, the valve body and the valve seat are arranged to contact and separate in a direction parallel to the direction of movement of the main valve, When the pressure of the pilot supply air supplied to the pilot supply port is higher than a predetermined pressure, the main valve is in a state of moving toward the first end side in the sleeve, and the first on-off valve and the second on-off valve are moved to each other. is set to be closed, and the aforementioned third on-off valve is set to be opened; and when the pressure of the pilot supply air supplied to the aforementioned pilot supply port is lower than a predetermined pressure, the aforementioned main valve becomes to move toward the second end portion side in the aforementioned sleeve state, the first on-off valve and the second on-off valve are opened, and the third on-off valve is closed. The switching valve according to claim 1, wherein the minimum cross-sectional area of the second flow path is smaller than the minimum cross-sectional area of the first flow path. The switching valve according to claim 1 or 2, further comprising a biasing member, and the biasing member is biased in a direction to move the main valve in the sleeve toward the second end. The switching valve according to claim 3, wherein the predetermined pressure is a pressure obtained by adding the pressure of the supply air supplied to the supply port to the pressure converted from the biasing force of the biasing member. The switching valve according to any one of claims 1 to 4, wherein the valve seat is formed using a metal material or a resin material, and a plating treatment or grease coating is performed on a contact surface with the valve body. The switching valve according to any one of claims 1 to 5, wherein the supply port is configured to be used in connection with an exhaust port of a cylinder incorporated in an external air compressor.

Images