switching valve

Abstract

The present application provides a switching valve capable of controlling flow rate in stages and preventing delay of switching point of flow rate at the time of resuming after use is stopped. The switching valve includes a main valve movable in a sleeve, a first flow path and a first opening and closing valve provided to communicate a pilot supply port with a release port, a second flow path and a second opening and closing valve to communicate the supply port with the release port, a third flow path and a third opening and closing valve to communicate the supply port with a first exhaust port, a fourth flow path to communicate the supply port with a second exhaust port, in the first and second opening and closing valves, a valve core and a valve seat are in contact and separation in a moving direction of the main valve, at the time of pilot supply air being greater than a prescribed pressure, the first and second opening and closing valves are closed and the third opening and closing valve is opened, at the time of being less than the prescribed pressure, the first and second opening and closing valves are opened and the third opening and closing valve is closed.

Description

Technical Field

[0001] This invention relates to a switching valve for air compression. Background Technology

[0002] In automated production lines that assemble mechanical devices, electronic equipment, and the like, cylinders are widely used. However, while increasing the speed of the piston in the cylinder can reduce cycle time, it also increases the impact upon stopping, thus shortening the cylinder's lifespan.

[0003] In the past, in order to reduce the impact when the cylinder (piston) stops even when the piston moves at a high speed, the following method was generally used: a shock absorber (e.g., oil type) was installed in the mechanism connecting the piston to the cylinder to mitigate the impact when the cylinder (piston) stops.

[0004] Alternatively, a technology involving a cylinder with a buffer mechanism is also disclosed: by providing a buffer mechanism to mitigate the impact when the cylinder stops, the impact is mitigated (see Patent Document 1: Japanese Patent Application Publication No. 2003-254303).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-254303

[0008] Patent Document 2: Japanese Patent Application Publication No. 2014-055631

[0009] However, in structures where shock absorbers are installed to mitigate the impact when the cylinder piston stops, technical problems arise such as increased mechanism complexity, component costs, and assembly costs because the shock absorbers need to be installed into the device.

[0010] In order to solve the above-mentioned technical problems, the inventors of this application have developed a speed controller with a buffer function, which can control the movement speed of a cylinder (piston) installed in an external air compressor in a single stroke in stages through a simple structure without using a shock absorber (see Patent Document 2: Japanese Patent Application Publication No. 2014-055631).

[0011] Here, when using a speed controller with a buffer function to control the movement speed of the cylinder (piston) of an external air compressor in stages during a single stroke, it is important to stabilize the speed switching point specified by the switching point of the gas flow. For example, if there is a delay in the speed switching point, a large impact will occur because the buffer cannot perform its function before the cylinder (piston) stroke ends.

[0012] After careful study, the inventors of this application discovered that the following technical problem has become significant in conventional speed controllers with buffer function: when restarting after a period of inactivity, the main valve or equivalent component may stick, and the flow switching point, i.e. the speed switching point, may be delayed during the initial stroke after restarting. Summary of the Invention

[0013] The present invention was 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 compression device, capable of controlling the flow rate of the gas passing through in stages, and preventing a delay in the flow switching point when restarting after a period of inactivity.

[0014] As one implementation method, the aforementioned technical problem is solved by the following disclosed solutions.

[0015] A switching valve is disclosed, characterized by comprising the following structure: a sleeve, the sleeve being cylindrical and having a supply port, a first exhaust port, a second exhaust port, a pilot supply port, and a release port formed as openings to allow communication between the inside and outside; and a main valve, the main valve being configured to move along an axial direction within the sleeve, and having a first flow path, a second flow path, a third flow path, and a fourth flow path arranged to pass through the sleeve, wherein the first flow path connects the pilot supply port to the release port, the second flow path connects the supply port to the release port, the third flow path connects the supply port to the first exhaust port, and the fourth flow path connects the supply port to the second exhaust port, and is provided with a first on-off valve, a second on-off valve, and a third on-off valve, wherein the first on-off valve opens or closes the first flow path, and the second on-off valve opens or closes the second flow path. The third on / off valve opens or closes the third flow path. In the first, second, and third on / off valves, one of the valve core and valve seat is integrally or separately disposed with the sleeve, and the other is integrally or separately disposed with the main valve. In the first and second on / off valves, the valve core and valve seat are configured to contact and separate in a direction parallel to the movement direction of the main valve. When the pressure of the pilot supply air supplied to the pilot supply port is greater than the specified pressure, the main valve moves towards the first end side within the sleeve, closing the first and second on / off valves and opening the third on / off valve. When the pressure of the pilot supply air supplied to the pilot supply port is less than the specified pressure, the main valve moves towards the second end side within the sleeve, opening the first and second on / off valves and closing the third on / off valve.

[0016] According to the disclosed switching valve, when used in conjunction with an external air compressor, the flow rate of the gas passing through can be controlled in stages. Furthermore, it prevents delays in the flow switching point when restarting after a period of inactivity. Attached Figure Description

[0017] Figure 1 This is a schematic diagram and an operational illustration of a structural example of a switching valve according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram and an operational illustration of a structural example of a switching valve according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram and an operational illustration of a structural example of a switching valve according to an embodiment of the present invention.

[0020] Figure 4 This is a circuit diagram illustrating an example of connecting the switching valve of an embodiment of the present invention to an external air compression device.

[0021] Figure 5 This is an explanatory diagram (experimental data of a conventional mechanism) used to illustrate the technical problem to be solved by the switching valve of the embodiment of the present invention.

[0022] Figure 6 This is an explanatory diagram illustrating the effect achieved by the switching valve according to an embodiment of the present invention (experimental data of the switching valve according to an embodiment of the present invention). Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figures 1-3 This is a front sectional view (general view) showing a structural example of the switching valve 1 in this embodiment, which also serves as an operational explanation diagram. Furthermore, in all the drawings used to explain the embodiments, components with the same function are sometimes labeled with the same symbols, and repeated descriptions are omitted.

[0024] As an example, the switching valve 1 in this embodiment is configured (connected) to a flow path through which the exhaust (compressed air at a specified pressure discharged by the movement of the piston) of the reciprocating cylinder (hereinafter referred to as "cylinder") C flows, thereby controlling the operating speed of the cylinder C in stages (for example, in two stages: high speed and low speed). The reciprocating cylinder is installed in an external air compression device that constitutes an automated production line or the like.

[0025] like Figures 1-3As shown, the switching valve 1 is configured to include a main valve 50, which is arranged within a cylindrical (for example, approximately cylindrical) sleeve 10 and is movable along the axial direction (along the direction of the central axis S). The sleeve 10 has a space at its radial center. Furthermore, as the constituent materials of the switching valve 1, in addition to the sealing members and the like which can use rubber, elastomers, etc. (described later), resin materials (e.g., POM, PBT, etc.) and metal materials (e.g., stainless steel alloys, aluminum alloys, brass, etc.) can be appropriately used depending on the operating conditions.

[0026] In this embodiment, the sleeve 10 is configured such that a cylindrical (for example, generally cylindrical) first guide sleeve 14 and a cylindrical (for example, generally cylindrical) second guide sleeve 16 are respectively fitted into the inner cylinder portion of a cylindrical (for example, generally cylindrical) main sleeve 12, sandwiching sealing members 18A, 18B, and 18C (for example, O-rings made of rubber, elastomers, etc.). The first guide sleeve 14, the second guide sleeve 16, and the main sleeve 12 all have a space at their radial centers. Therefore, the main valve 50, which moves along the axial direction within the sleeve 10, is more specifically configured to move along the axial direction within the first guide sleeve 14 and the second guide sleeve 16 (i.e., within their respective spaces). However, the structure of the sleeve 10 is not limited to the above situation. As a variation, it can also be configured to form the sleeve 10 as a whole, or to form the first guide sleeve 14 and the second guide sleeve 16 as a whole (none of which are shown in the figure).

[0027] The sleeve 10 is provided with the following ports formed as openings to allow communication between the inside and outside of the cylindrical portion (i.e., to allow communication between the inside and outside of the fitted main sleeve 12, the first guide sleeve 14, and the second guide sleeve 16 as a whole). Specifically, it is provided with a supply port 20, a first exhaust port 22, a second exhaust port 24, a pilot supply port 26, and a release port 28.

[0028] Furthermore, for each of the aforementioned ports, the following flow path is provided, which is formed between the inner cylinder portion of the sleeve 10 and the outer periphery of the main valve 50 (to avoid complicating the diagram, in...). Figure 2 (represented in the text). Specifically, a first flow path 31 is provided that connects the pilot supply port 26 to the release port 28, a second flow path 32 that connects the supply port 20 to the release port 28, a third flow path 33 that connects the supply port 20 to the first exhaust port 22, and a fourth flow path 34 that connects the supply port 20 to the second exhaust port 24.

[0029] Furthermore, a first on / off valve 41 is provided to open or close the first flow path 31, a second on / off valve 42 to open or close the second flow path 32, and a third on / off valve 43 to open or close the third flow path 33 (to avoid complicating the diagram). Figure 2 , Figure 3 (represented in Chinese).

[0030] In the first on / off valve 41, a valve core 41a, made of rubber, elastomer, or other materials, is disposed on the main valve 50, and a valve seat 41b is integrally disposed with the sleeve 10 (in this embodiment, the first guide sleeve 14) (or they can be disposed separately). Furthermore, as a variation, a structure in which the valve core 41a is disposed on the sleeve 10 and the valve seat 41b is disposed on the main valve 50 is also considered (not shown).

[0031] Similarly, in the second on / off valve 42, a valve core 42a, formed separately from rubber, elastomer, etc., is disposed on the main valve 50, and the valve seat 42b is integrally disposed with the sleeve 10 (in this embodiment, the first guide sleeve 14) (or may be disposed separately). Furthermore, as a variation, a structure in which the valve core 42a is disposed on the sleeve 10 and the valve seat 42b is disposed on the main valve 50 is also considered (not shown). In addition, in the third on / off valve 43, a valve core 43a, formed separately from rubber, elastomer, etc., is disposed on the main valve 50, and the valve seat 43b is integrally disposed with the sleeve 10 (in this embodiment, the first guide sleeve 14) (or may be disposed separately). Furthermore, as a variation, a structure in which the valve core 43a is disposed on the sleeve 10 and the valve seat 43b is disposed on the main valve 50 is also considered (not shown).

[0032] Furthermore, in this embodiment, the following structure is adopted: the valve core 41a of the first on / off valve 41 and the valve core 42a of the second on / off valve 42 are integrated into a gasket member 40, and the gasket member 40 is embedded in the outer periphery of the main valve 50. This reduces the number of components and lowers costs. However, the structure is not limited to the above; the valve core 41a and valve core 42a can also be constructed separately (not shown).

[0033] Here, a gas at a predetermined pressure (for example, compressed air at approximately 0.5 MPa) is supplied (input) at the pilot supply port 26 as "pilot supply air". On the other hand, a gas at a predetermined pressure (for example, compressed air at approximately 0.5 MPa) is supplied (input) at the supply port 20 as "supply air". The various gases (compressed air) can, for example, be supplied from a common supply source (for example, a compressor pump). However, it is not limited to this; a structure can also be adopted where the gas is supplied from different supply sources (for example, a compressor pump) (not shown).

[0034] The switching valve 1, including the above-described structure, operates as follows. Specifically, when the pressure of the pilot supply air supplied to the pilot supply port 26 is greater than a predetermined pressure (hereinafter referred to as the "first set pressure"), the main valve 50 moves within the sleeve 10 towards the first end (right end in the figure) 10a. Figure 1 In the state shown, the first on / off valve 41 and the second on / off valve 42 are "closed," and the third on / off valve 43 is "opened." On the other hand, when the pressure of the pilot supply air supplied to the pilot supply port 26 is lower than the specified pressure (first set pressure), the main valve 50 moves within the sleeve 10 towards the second end (left end in the figure) 10b. Figure 3 (As shown in the diagram), the first on / off valve 41 and the second on / off valve 42 are "opened," and the third on / off valve 43 is "closed." Additionally, Figure 2 The state shown is from Figure 1 The state transition shown is to Figure 3 The state shown is in the middle, or from Figure 3 The state transition shown is to Figure 1 The state shown is the state in progress.

[0035] Therefore, as an example, it is possible to switch between a circuit in which the supply air supplied to the supply port 20 is discharged from both the first exhaust port 22 and the second exhaust port 24, and a circuit in which the air is discharged only from the second exhaust port 24. Specifically, the exhaust flow path can be switched between the third flow path 33 and the fourth flow path 34, thus the flow rate of the compressed air can be switched by changing the cross-sectional area (narrowest part) of the flow path. Furthermore, throttle valves 62 and 64 (see reference) are respectively provided in the third flow path 33 and the fourth flow path 34. Figure 4 This transforms the structure into one that can regulate the flow rate of compressed air passing through each flow path.

[0036] Here, as an example of the use (connection example) of the switching valve 1 in this embodiment, such as Figure 4 As shown in the circuit diagram, the supply port 20 of the switching valve 1 is connected to the exhaust port of the cylinder C, which is installed in an external air compressor. At this time, when compressed air at a specified pressure (here, 0.5 MPa, etc.) is supplied to the intake port of the cylinder C to move the piston, compressed air at the same pressure is discharged from the exhaust port. This constitutes the structure where the compressed air is supplied (input) to the supply port 20 of the switching valve 1.

[0037] Therefore, the switching valve 1 can achieve the following function: it can switch between a circuit in which the supply air supplied to the supply port 20 is discharged from both the first exhaust port 22 and the second exhaust port 24, and a circuit in which the air is discharged only from the second exhaust port 24. That is, it can switch the cross-sectional area of ​​the flow path for exhausting the external air compressor (cylinder C) in stages (in this case, two stages). As a result, the piston's movement speed (axial movement speed) in cylinder C can be switched from high speed to low speed, thereby producing a buffering function. Therefore, the speed before the piston stops can be reduced, thus mitigating the impact when stopping.

[0038] Furthermore, as another example, by employing a structure that includes an on / off valve (not shown) to open or close the fourth flow path 34, it is possible to switch between a circuit where the supply air supplied to the supply port 20 is discharged only from the first exhaust port 22 and a circuit where it is discharged only from the second exhaust port 24. With such a structure, the same effect as described above can be achieved, namely, a buffering function can be generated by switching the flow rate of the compressed air.

[0039] However, if the buffering function is only generated during the piston movement of cylinder C, it can be achieved, as mentioned earlier, using conventional speed controllers with buffering functions, spool-type switching valves, etc. However, in conventional products, the following problem becomes significant: after a period of inactivity, upon restarting, the internal main valve (or a component equivalent to the main valve) may stick, potentially causing a delay in the flow switching point, i.e., the speed switching point, during the initial stroke after restarting. Here, experimental results using a conventional mechanism will be presented... Figure 5 The diagram shows the time between shutdown and restart. Curve A1 represents the standard data during normal operation, curve A2 represents the data after a 10-minute shutdown and restart, and curve A3 represents the data after a 3-hour shutdown and restart. In curves A1 to A3, the vertical axis represents the pilot air pressure, and the horizontal axis represents the response delay time of the main valve 50 in response to changes in the pilot air pressure (start of movement). As can be seen from the graphs, the longer the shutdown time, the slower the main valve 50's response (start of movement). Figure 5 The greater the delay time before point E in the equation, the greater the adhesion of the main valve 50.

[0040] To solve the aforementioned technical problems, the switching valve 1 of this embodiment includes the following structure. First, in the first on / off valve 41 and the second on / off valve 42, the valve core and valve seat (specifically, valve core 41a and valve seat 41b, and valve core 42a and valve seat 42b) are arranged to contact and separate in a direction parallel to the movement direction of the main valve 50 (i.e., the same direction parallel to the central axis S of the inner cylinder portion of the sleeve 10). Through the research of the inventors of this application, it has been found that the adhesion of the main valve, a technical problem, is caused by the tight-fitting state achieved by the pressing of the valve cores provided in each on / off valve with the corresponding valve seats. In contrast, according to the aforementioned structure, even if the valve cores (here, 41a, 42a) and the corresponding valve seats (here, 41b, 42b) are pressed together and a tight-fitting state is generated, the tight-fitting state is easily eliminated, thereby eliminating (or suppressing) the occurrence of adhesion.

[0041] Here, experimental results using the switching valve 1 of this embodiment, which includes the structure described above, will be presented. Figure 6 The diagram shows the data. Curve B1 represents the standard data during normal operation, while curve B2 represents the data after a 3-hour shutdown followed by restarting. Additionally, the indices on the vertical and horizontal axes are related to... Figure 5 The same applies. As can be seen from the graph, according to the switching valve 1 of this embodiment, even if the time of inactivity is longer, the adhesion of the main valve 50 is almost (or very small).

[0042] Furthermore, as a variation, the following structure can be adopted: valve seats 41b, 42b, and 43b are formed using metal or resin materials, and a plating treatment or grease coating is applied to all or part of them, and to the contact surfaces with the corresponding valve cores 41a, 42a, and 43a, to reduce the coefficient of friction. In this way, even if the valve cores (41a and 42a in this case) are pressed together with the corresponding valve seats (41b and 42b in this case) and a tight-fitting state occurs, the tight-fitting state is easily eliminated, thereby further improving the effect of eliminating (or suppressing) adhesion.

[0043] Furthermore, the switching valve 1 in this embodiment includes a structure characterized in that the minimum cross-sectional area of ​​the second flow path 32 (located at its narrowest point between the inner cylinder portion of the first guide sleeve 14 and the outer periphery of the main valve 50) is smaller than the minimum cross-sectional area of ​​the first flow path 31 (located downstream of the first on / off valve 41 and before the outlet of the release port 28). Assuming the minimum cross-sectional area of ​​the second flow path 32 is larger than or equal to the minimum cross-sectional area of ​​the first flow path 31, when the main valve 50 moves, the compressed air supplied to the supply port 20 flows into the pilot supply port 26 side, causing the thrust generated by the pressure of the pilot supply air to rise above a set value. As a result, the main valve 50 cannot switch stably at the specified time.

[0044] To address the aforementioned problems, this embodiment solves them by providing a release port 28 (details will be described later) that releases the exhaust of the pilot supply air to the atmosphere, and by making the minimum cross-sectional area of ​​the second flow path 32 smaller than that of the first flow path 31, as described above. That is, according to this structure, when the main valve 50 is switched (moved) in the direction that opens the first on / off valve 41, all the pilot supply air is released to the atmosphere, resulting in almost no (or minimal) flow through the second flow path 32 to the supply port 20. Furthermore, the supply air flowing from the supply port 20 through the second flow path 32 flows to the release port 28 instead of the pilot supply port 26, thus almost no (or minimal) thrust generated by the pressure of the pilot supply air rises above a set level. Therefore, the movement of the main valve 50, i.e., the switching, can be performed stably at the desired time. Additionally, the speed controller 66 (see reference...) Figure 4 Set the switching time.

[0045] As described above, in this embodiment, the release port 28 employs a structure that releases the flowing gas at atmospheric pressure. However, it is not limited to the above structure; even if a structure is used to release the flowing gas at a very low pressure (e.g., around 0.2 MPa or less), the same effect can be achieved.

[0046] Furthermore, the switching valve 1 in this embodiment also includes a force-applying member (e.g., a coil spring or other spring member) 60, which applies force in the direction that moves the main valve 50 within the sleeve 10 toward the second end 10b. This assists in the movement of the main valve 50 and stabilizes its position when no air supply is applied (or a small amount of air supply is applied). The force applied by the force-applying member 60 (e.g., a coil spring) is appropriately set according to the dimensions of the sleeve 10 and the main valve 50; for example, it is set to generate approximately 1N of force upon insertion.

[0047] When a structure including the spring 60 described above is adopted, the aforementioned "first setting force" is set to the pressure obtained by adding the pressure of the supply air supplied to the supply port 20 to the pressure obtained by converting the force applied by the force-applying member 60 (e.g., a coil spring).

[0048] 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, the "supply air" is supplied along with cylinder C). Therefore, it is necessary to adjust the pressure of the pilot supply air to be higher than the first set pressure.

[0049] Regarding this, in this embodiment, the main valve 50 is configured such that the pressure-bearing area of ​​the pilot supply air supplied from the pilot supply port 26 (specifically, the pressure-bearing area defined by the diameter of the valve core 41a (the contact position with the valve seat 41b)) is larger than the pressure-bearing area of ​​the supply air supplied from the supply port 20 (specifically, the pressure-bearing area defined by the diameter of the valve core 42a (the contact position with the valve seat 42b)). According to this configuration, the thrust that moves the main valve 50 towards the first end 10a by the pressure of the pilot supply air can be set to be larger than the thrust that moves the main valve 50 towards the second end 10b by the pressure of the supply air and the force applied by the force-applying member 60. Furthermore, as an example, since in the usage mode where the supply port 20 is connected to the exhaust port of the cylinder C, the exhaust gas flow rate is high and the supply air pressure is low, the combined effect of these conditions enhances and maintains the state where the thrust generated by the pressure of the pilot supply air is higher.

[0050] As explained above, according to the disclosed switching valve, for gas supplied (input) at a specified pressure to the supply port, the flow rate of the discharged gas can be controlled in stages (in this case, two stages). For example, if configured to connect to the exhaust port of a cylinder installed in an external air compressor, the piston of the cylinder can move at high speed for a period of time after it begins to move, thereby shortening the action time, and the movement speed can be switched from high speed to low speed at a set moment just before the piston stops. Therefore, shock absorption when the piston of the cylinder stops can be achieved without using a shock absorber.

[0051] Furthermore, the switching valve can prevent the following situation: when restarting after a period of inactivity, the flow switching point is delayed due to the main valve sticking to the sleeve.

[0052] Furthermore, 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 goes without saying.

Claims

1. A switching valve, characterized in that, The structure includes the following: A sleeve, the sleeve being cylindrical, and having a supply port, a first exhaust port, a second exhaust port, a pilot supply port, and a release port formed as openings to allow communication between the inside and outside; and The main valve is configured to move along the axial direction within the sleeve. The sleeve is provided with a first flow path, a second flow path, a third flow path, and a fourth flow path. The first flow path connects the pilot supply port to the release port, the second flow path connects the supply port to the release port, the third flow path connects the supply port to the first exhaust port, and the fourth flow path connects the supply port to the second exhaust port. A first on-off valve, a second on-off valve, and a third on-off valve are also provided. The first on-off valve opens or closes the first flow path, the second on-off valve opens or closes the second flow path, and the third on-off valve opens or closes the third flow path. In the first, second, and third on / off valves, one of the valve core and valve seat is either integrally or separately disposed with the sleeve, while the other is integrally or separately disposed with the main valve. In both the first and second on / off valves, the valve core and the valve seat are configured to contact and separate in a direction parallel to the movement direction of the main valve. When the pressure of the pilot supply air supplied to the pilot supply port is greater than the specified pressure, the main valve moves towards the first end within the sleeve, closing the first and second on / off valves and opening the third on / off valve. When the pressure of the pilot supply air supplied to the pilot supply port is less than the specified pressure, the main valve moves towards the second end within the sleeve, opening the first and second on / off valves and closing the third on / off valve.

2. The switching valve as described in claim 1, characterized in that, The minimum cross-sectional area of ​​the second flow path is smaller than the minimum cross-sectional area of ​​the first flow path.

3. The switching valve as described in claim 1 or 2, characterized in that, It also includes a force-applying component that applies force in a direction that causes the main valve to move within the sleeve toward the second end.

4. The switching valve as described in claim 3, characterized in that, The specified pressure is the pressure obtained by adding the pressure of the supply air supplied to the supply port to the pressure after converting the force applied by the force-applying component.

5. The switching valve as described in claim 1 or 2, characterized in that, The valve seat is formed of metal or resin material, and is plated or coated with grease on the contact surface with the valve core.

6. The switching valve as described in claim 1 or 2, characterized in that, It is configured to connect the supply port to the exhaust port of a cylinder installed in an external air compressor.

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