Pulse air generation device

Abstract

To enable obtaining a desired discharge time and cutoff time while avoiding unintentional change of a cycle length.SOLUTION: An on-duty ratio, which is a ratio of a discharge time during which air is discharged from a discharge port 14 to the outside to a cut-off time during which discharge of the air from the discharge port 14 is blocked, is adjusted based on a value obtained by dividing a pressure receiving area of a first spool pressure receiving surface 82 by a pressure receiving area of a first piston pressure receiving surface 81 and a value obtained by dividing a pressure receiving area of a second spool pressure receiving surface 84 by a pressure receiving area of a second piston pressure receiving area 83. Further, the pressure receiving areas of the first piston pressure receiving surface 81, the first spool pressure receiving surface 82, the second piston pressure receiving surface 83, and the second spool pressure receiving surface 84 are pre-set so as to obtain a desired cut-off time.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pulsed air generator. [Background technology]

[0002] Pulse air generators that intermittently discharge air from a discharge port have been known for some time. For example, the pulse air generator disclosed in Patent Document 1 includes two adjustment valves that adjust the flow rate of air. One adjustment valve adjusts the discharge time during which air is discharged from the discharge port, and the other adjustment valve adjusts the cut-off time during which the discharge of air from the discharge port is cut off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-167436 Summary of the Invention [Problem to be solved by the invention]

[0004] In the pulse air generator of Patent Document 1, for example, suppose one of the adjusting valves is used to adjust the discharge time during which air is discharged from the discharge port. This unintentionally changes the length of the cycle, which is the time from when air is discharged from the discharge port until the discharge of air from the discharge port is stopped and the discharge of air from the discharge port is resumed. Furthermore, suppose the other adjusting valve is used to adjust the interruption time during which air discharge from the discharge port is interrupted. This unintentionally changes the length of the cycle. Therefore, in order to adjust the discharge time and the interruption time without changing the length of the cycle, fine adjustment of the two adjusting valves is required simultaneously, which is a complicated process. Therefore, there is a need for a pulse air generator that can obtain desired discharge times and interruption times while avoiding unintentional changes in the length of the cycle. [Means for solving the problem]

[0005] Various aspects for solving the above problems will be described below. [Aspect 1] A pulse air generator that intermittently discharges air from a discharge port, Body and a valve hole formed in the body; a first spool valve and a second spool valve that are accommodated in the valve hole so as to be able to reciprocate and are arranged adjacent to each other in the axial direction of the valve hole; a supply port, a first output port, a second output port, and a discharge port formed in the body and communicating with the valve hole, respectively; a first piston provided at an end of the first spool valve and moving integrally with the first spool valve; a second piston provided at an end of the second spool valve and moving integrally with the second spool valve; a first pilot chamber to which pilot air for moving the first piston is supplied and discharged; a second pilot chamber to which pilot air for moving the second piston is supplied and discharged; a first communication passage connected to the discharge port and communicating between the first output port and the first pilot chamber; a second communication passage communicating the second output port and the second pilot chamber, when air is discharged from the first pilot chamber, the first spool valve switches to a first position where it blocks the flow of air between the supply port and the second output port and allows the flow of air between the second output port and the exhaust port, and when air is supplied to the first pilot chamber, it switches to a second position where it allows the flow of air between the supply port and the second output port and blocks the flow of air between the second output port and the exhaust port, the second spool valve is switched to a third position allowing air to flow between the supply port and the first output port when the first spool valve is switched to the first position, and is switched to a fourth position blocking air to flow between the supply port and the first output port when the first spool valve is switched to the second position; the first piston has a first piston pressure-receiving surface that receives pressure of pilot air supplied to the first pilot chamber to move the first spool valve from the first position to the second position, the first spool valve has a first spool pressure-receiving surface that receives pressure of air supplied from the supply port on the side opposite to the first piston in order to move the first spool valve from the second position to the first position, the second piston has a second piston pressure-receiving surface that receives pressure of pilot air supplied to the second pilot chamber to move the second spool valve from the third position to the fourth position, the second spool valve has a second spool pressure-receiving surface that receives pressure of air supplied from the supply port on the side opposite to the second piston in order to move the second spool valve from the fourth position to the third position, a duty ratio, which is the ratio between a discharge time during which air is discharged to the outside from the discharge port and a cut-off time during which the discharge of air from the discharge port is cut off, is adjusted based on a value obtained by dividing a pressure-receiving area of ​​the first spool pressure-receiving surface by a pressure-receiving area of ​​the first piston pressure-receiving surface and a value obtained by dividing a pressure-receiving area of ​​the second spool pressure-receiving surface by a pressure-receiving area of ​​the second piston pressure-receiving surface.

[0006] [Aspect 2] The pulsed air generator according to [Aspect 1], wherein the first communication flow path or the second communication flow path is provided with an adjustment valve that adjusts the flow rate of air flowing through the first communication flow path or the second communication flow path, in order to adjust the length of a cycle that is the time from when air is discharged from the discharge port until the discharge of air from the discharge port is stopped and the discharge of air from the discharge port is started again.

[0007] [Aspect 3] the regulating valve has a columnar regulating valve body that regulates the opening degree of a regulating valve hole that forms a part of the first communication flow path or the second communication flow path, The body has an insertion hole formed therein, the insertion hole having a first end opening to an outer surface of the body and a second end communicating with the adjustment valve hole, The adjustment valve body is inserted into the insertion hole so as to be capable of reciprocating motion, a recess extending in the axial direction of the adjustment valve body is formed on the outer peripheral surface of the adjustment valve body, A stopper member is provided in the insertion hole, The pulse air generator according to [Aspect 2], wherein the stopper member is engaged with a portion of the recess located on a first end side of the insertion hole, thereby restricting movement of the adjustment valve body in a direction to close the adjustment valve hole, and is engaged with a portion of the recess located on a second end side of the insertion hole, thereby restricting movement of the adjustment valve body in a direction to open the adjustment valve hole.

[0008] [Aspect 4] The first pilot chamber is a first piston chamber in which the first piston reciprocates; a first expansion chamber communicating with the first piston chamber, The second pilot chamber is a second piston chamber in which the second piston reciprocates; The pulsed air generator according to any one of [Aspect 1] to [Aspect 3], further comprising a second expansion chamber communicating with the second piston chamber. [Effects of the Invention]

[0009] According to this invention, it is possible to obtain the desired discharge time and shut-off time while avoiding unintentional changes in the length of the cycle. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a cross-sectional view showing an air blow gun according to an embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing a part of the air blow gun. [Figure 3] FIG. 3 is a perspective view showing a part of the air blow gun. [Figure 4] FIG. 4 is a front view showing a part of the air blow gun. [Figure 5] FIG. 5 is an enlarged cross-sectional view showing a part of the air blow gun. [Figure 6] FIG. 6 is an enlarged cross-sectional view showing a part of the air blow gun. [Figure 7] FIG. 7 is an enlarged cross-sectional view showing a part of the air blow gun. [Figure 8] FIG. 8 is an enlarged cross-sectional view showing a part of the air blow gun. [Figure 9] FIG. 9 is a graph showing the relationship between the on-duty ratio and the pressure-receiving area of ​​the first piston pressure-receiving surface. [Figure 10] FIG. 10 is a graph showing the relationship between the on-duty ratio and the value obtained by dividing the pressure-receiving area of ​​the first spool pressure-receiving surface by the pressure-receiving area of ​​the first piston pressure-receiving surface. [Figure 11] 11(a), 11(b), 11(c), 11(d) and 11(e) are time charts showing the state in which air is intermittently discharged from the discharge port. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment in which a pulse air generator is embodied in an air blow gun will be described below with reference to Figs. <Overall configuration of the air blow gun> As shown in Fig. 1, an air blow gun 10, which is a pulse air generator, includes a pulse generating unit 11 and a manual valve unit 12. The pulse generating unit 11 includes a body 13. Therefore, the air blow gun 10 includes the body 13. The air blow gun 10 includes a discharge port 14. The air blow gun 10 intermittently discharges air from the discharge port 14.

[0012] The body 13 has a valve casing 15 and a flow path forming block 16. The valve casing 15 has a casing main body 18, a first connecting block 19, and a second connecting block 20. The casing main body 18 is made of, for example, aluminum alloy die-casting. The first connecting block 19 and the second connecting block 20 are made of, for example, a synthetic resin material.

[0013] As shown in FIG. 2 , the casing body 18 has a shape of an elongated rectangular block. The casing body 18 has a first end face 181 facing the first connecting block 19. The first end face 181 is an end face located on one side of the casing body 18 in the longitudinal direction. The casing body 18 has a second end face 182 facing the second connecting block 20. The second end face 182 is an end face located on the other side of the casing body 18 in the longitudinal direction. The casing body 18 also has a third end face 183 facing the flow path forming block 16. The casing body 18 also has a fourth end face 184, which is a face located on the opposite side of the third end face 183. The third end face 183 and the fourth end face 184 each extend in the longitudinal direction of the casing body 18. The third end face 183 and the fourth end face 184 connect the first end face 181 and the second end face 182.

[0014] The air blow gun 10 has a valve hole 21. The valve hole 21 is formed in the casing main body 18. Therefore, the valve hole 21 is formed in the body 13. The valve hole 21 is a circular hole. The valve hole 21 extends in the longitudinal direction of the casing main body 18. A first end of the valve hole 21 opens to a first end face 181 of the casing main body 18. A second end of the valve hole 21 opens to a second end face 182 of the casing main body 18. Therefore, the valve hole 21 passes through the casing main body 18 in the longitudinal direction.

[0015] The air blow gun 10 has a supply port 22, a first output port 23, a second output port 24, and a discharge port 25. The supply port 22, the first output port 23, the second output port 24, and the discharge port 25 are formed in the casing main body 18. Therefore, the supply port 22, the first output port 23, the second output port 24, and the discharge port 25 are formed in the body 13. The supply port 22, the first output port 23, the second output port 24, and the discharge port 25 are each communicated with the valve hole 21. The discharge port 25, the second output port 24, the supply port 22, and the first output port 23 are formed in the casing main body 18 in this order from one end to the other end in the longitudinal direction of the casing main body 18. The supply port 22, the first output port 23, the second output port 24, and the discharge port 25 open to a third end face 183. The supply port 22 and the second output port 24 also open to the fourth end surface 184 .

[0016] A communication port 26 is formed in the casing body 18. The communication port 26 is disposed between the supply port 22 and the second output port 24 in the longitudinal direction of the casing body 18. The communication port 26 communicates with the valve hole 21. The communication port 26 opens to the third end face 183.

[0017] The first connecting block 19 has a first connecting surface 191 that is connected to a first end surface 181 of the casing main body 18. The first connecting block 19 is connected to the casing main body 18 with the first connecting surface 191 and the first end surface 181 of the casing main body 18 abutting against each other. The first connecting block 19 also has an opposing surface 192 that faces the flow path forming block 16. The first connecting block 19 has a first piston accommodating recess 19a. The first piston accommodating recess 19a opens to the first connecting surface 191.

[0018] The second connection block 20 has a second connection surface 201 that is connected to the second end surface 182 of the casing main body 18. The second connection block 20 is connected to the casing main body 18 with the second connection surface 201 and the second end surface 182 of the casing main body 18 abutting against each other. The second connection block 20 also has an opposing surface 202 that faces the flow path forming block 16. The second connection block 20 has a second piston accommodating recess 20a. The second piston accommodating recess 20a opens to the second connection surface 201.

[0019] The flow path forming block 16 has a flat rectangular block shape. The flow path forming block 16 has block surfaces 161 that are arranged opposite the third end surface 183 of the casing main body 18, the opposing surface 192 of the first connecting block 19, and the opposing surface 202 of the second connecting block 20. The block surfaces 161 extend in the longitudinal direction of the flow path forming block 16. The flow path forming block 16 is connected to the casing main body 18 with a gasket 28 interposed between the block surface 161 and the third end surface 183 of the casing main body 18.

[0020] The passage-forming block 16 is formed with an insertion hole 16a and a joint mounting hole 16b. Therefore, the body 13 is formed with the insertion hole 16a. A first end of the insertion hole 16a opens into an end face located on one side in the longitudinal direction of the passage-forming block 16. Therefore, the first end of the insertion hole 16a opens into the outer surface of the body 13. A first end of the joint mounting hole 16b opens into an end face located on the other side in the longitudinal direction of the passage-forming block 16.

[0021] The passage-forming block 16 is formed with a first-block communication passage 16c, a second-block communication passage 16d, and a third-block communication passage 16e. The passage-forming block 16 also has a regulation valve hole 16h. A first end of the first-block communication passage 16c opens to the block face 161. A second end of the first-block communication passage 16c communicates with the middle of the second-block communication passage 16d. A first end of the second-block communication passage 16d communicates with the second end of the joint mounting hole 16b. A second end of the second-block communication passage 16d communicates with a first end of the regulation valve hole 16h. A second end of the regulation valve hole 16h communicates with the second end of the insertion hole 16a. Therefore, a first end of the insertion hole 16a opens to the outer surface of the body 13, and a second end communicates with the regulation valve hole 16h. A first end of the third block communication passage 16e opens to the inner circumferential surface of the insertion hole 16a. A second end of the third block communication passage 16e opens to a portion of the block surface 161 facing the first connection block 19.

[0022] An annular sealing member 29 is interposed between the portion of the block face 161 facing the first connecting block 19 and the facing face 192 of the first connecting block 19. The sealing member 29 seals the gap between the flow path forming block 16 and the first connecting block 19 at an opening on the block face 161 side of the third block communicating flow path 16e.

[0023] A communication passage 30 is formed in the block surface 161 of the flow passage forming block 16. The communication passage 30 connects the supply port 22 and the communication port 26. A block supply / discharge passage 17 is formed in the flow passage forming block 16. The block supply / discharge passage 17 has a first supply / discharge passage 17a, a second supply / discharge passage 17b, and a third supply / discharge passage 17c. A first end of the first supply / discharge passage 17a opens at a position on the block surface 161 facing the second output port 24. A second end of the first supply / discharge passage 17a is located inside the flow passage forming block 16. A first end of the second supply / discharge passage 17b connects to the second end of the first supply / discharge passage 17a. The second end of the second supply / discharge passage 17b is closed by a seal member 17d. A first end of the third supply / discharge passage 17c connects to a portion of the second supply / discharge passage 17b. A second end of the third supply / discharge path 17c opens to a portion of the block surface 161 facing the second connecting block 20. A first end of the first supply / discharge path 17a forms a first end of the block supply / discharge path 17. A second end of the third supply / discharge path 17c forms a second end of the block supply / discharge path 17.

[0024] An annular sealing member 38 is interposed between the portion of the block surface 161 facing the second connection block 20 and the opposing surface 202 of the second connection block 20. The sealing member 38 seals the gap between the flow path forming block 16 and the second connection block 20 at the opening of the block supply / discharge flow path 17 on the block surface 161 side.

[0025] The air blow gun 10 is equipped with a discharge port joint 31. The discharge port joint 31 has a discharge port 14. The discharge port joint 31 is attached to the joint mounting hole 16b. The discharge port 14 is in communication with the second block communication passage 16d via the joint mounting hole 16b.

[0026] The air blow gun 10 includes a first spool valve 32 and a second spool valve 33. The first spool valve 32 and the second spool valve 33 are accommodated in the valve hole 21 so as to be able to move back and forth. The first spool valve 32 and the second spool valve 33 are arranged adjacent to each other in the axial direction of the valve hole 21. The first spool valve 32 and the second spool valve 33 are accommodated in the valve hole 21 with the axis of the first spool valve 32 and the axis of the second spool valve 33 aligned with each other.

[0027] The air blow gun 10 includes a first piston 34 and a second piston 35. The first piston 34 is disk-shaped. The first piston 34 is connected to an end of the first spool valve 32 opposite to the second spool valve 33. Therefore, the first piston 34 is provided at an end of the first spool valve 32. The first piston 34 moves integrally with the first spool valve 32. The second piston 35 is disk-shaped. The second piston 35 is connected to an end of the second spool valve 33 opposite to the first spool valve 32. Therefore, the second piston 35 is provided at an end of the second spool valve 33. The second piston 35 moves integrally with the second spool valve 33. The outer diameter of the first piston 34 and the outer diameter of the second piston 35 are the same.

[0028] An end of the first spool valve 32 opposite to the second spool valve 33 can extend and retract from the valve hole 21 into the first piston accommodating recess 19a. A first piston 34 is accommodated in the first piston accommodating recess 19a. The first piston 34 can reciprocate within the first piston accommodating recess 19a. The first piston 34 defines a first piston chamber 36 within the first piston accommodating recess 19a. The first piston chamber 36 is a space located within the first piston accommodating recess 19a closer to the bottom wall of the first piston accommodating recess 19a than the first piston 34. The first piston 34 reciprocates within the first piston chamber 36. When the first spool valve 32 protrudes most deeply into the first piston accommodating recess 19a from the valve hole 21, the first piston 34 abuts against the bottom wall of the first piston accommodating recess 19a.

[0029] An end of the second spool valve 33 opposite to the first spool valve 32 can extend and retract from the valve hole 21 into the second piston accommodating recess 20a. A second piston 35 is accommodated in the second piston accommodating recess 20a. The second piston 35 is capable of reciprocating within the second piston accommodating recess 20a. The second piston 35 defines a second piston chamber 37 within the second piston accommodating recess 20a. The second piston chamber 37 is a space located closer to the bottom wall of the second piston accommodating recess 20a than the second piston 35 within the second piston accommodating recess 20a. The second piston 35 reciprocates within the second piston chamber 37. The second piston 35 abuts against the bottom wall of the second piston accommodating recess 20a when the second spool valve 33 protrudes most deeply into the second piston accommodating recess 20a from the valve hole 21.

[0030] A first expansion chamber 41 is formed in the first connecting block 19. The first expansion chamber 41 is in communication with the first piston chamber 36. The first piston chamber 36 and the first expansion chamber 41 form a first pilot chamber 45 to which pilot air that moves the first piston 34 is supplied and discharged. Therefore, the air blow gun 10 is provided with the first pilot chamber 45. In this way, the first pilot chamber 45 has the first piston chamber 36 and the first expansion chamber 41.

[0031] A second expansion chamber 42 is formed in the second connecting block 20. The second expansion chamber 42 is in communication with the second piston chamber 37. The second piston chamber 37 and the second expansion chamber 42 form a second pilot chamber 46 to which pilot air that moves the second piston 35 is supplied and discharged. Therefore, the air blow gun 10 is provided with the second pilot chamber 46. In this way, the second pilot chamber 46 has the second piston chamber 37 and the second expansion chamber 42.

[0032] 3 and 4 show the relationship between the first piston chamber 36 and the first expansion chamber 41. The relationship between the second piston chamber 37 and the second expansion chamber 42 is the same as the relationship between the first piston chamber 36 and the first expansion chamber 41, and therefore a detailed description thereof will be omitted.

[0033] 3 and 4, the first expansion chamber 41 is composed of a circular first hole 43 formed in the center of the bottom wall of the first piston accommodating recess 19a and a plurality of fan-shaped second holes 44 in a plan view formed around the first hole 43. The first hole 43 and each of the second holes 44 communicate with the first piston chamber 36.

[0034] As shown in FIG. 2, a first flow path 19b is formed in the first connecting block 19. A first end of the first flow path 19b opens to the opposing surface 192. The first end of the first flow path 19b communicates with the third block communication flow path 16e. A second end of the first flow path 19b communicates with one of the multiple second holes 44 that form the first expansion chamber 41. Therefore, the first flow path 19b communicates with the first pilot chamber 45.

[0035] A second flow path 20b is formed in the second connecting block 20. A first end of the second flow path 20b opens to the opposing surface 202. The first end of the second flow path 20b communicates with the third supply / discharge path 17c of the block supply / discharge path 17. A second end of the second flow path 20b communicates with one of the multiple second holes 44 that form the second expansion chamber 42. Therefore, the second flow path 20b communicates with the second pilot chamber 46.

[0036] The gasket 28 provides a seal between the third end surface 183 of the casing body 18 and the block surface 161 of the passage-forming block 16. The gasket 28 is formed with a first communication hole 28a, a second communication hole 28b, a third communication hole 28c, and a fourth communication hole 28d. The first communication hole 28a connects the first output port 23 to the first block communication passage 16c. The second communication hole 28b connects the supply port 22 to the communication passage 30. The third communication hole 28c connects the communication port 26 to the communication passage 30. The supply port 22 and the communication port 26 are always in communication with each other via the second communication hole 28b, the communication passage 30, and the third communication hole 28c. The fourth communication hole 28d connects the second output port 24 to the block supply / discharge passage 17.

[0037] <First communication channel> The air blow gun 10 has a first communication passage 51. The first communication passage 51 is composed of the first communication hole 28a, the first block communication passage 16c, the second block communication passage 16d, the adjustment valve hole 16h, the insertion hole 16a, the third block communication passage 16e, and the first passage 19b. Therefore, the first communication passage 51 is connected to the discharge port 14, and communicates between the first output port 23 and the first pilot chamber 45. The adjustment valve hole 16h forms a part of the first communication passage 51.

[0038] <Second communicating channel> The air blow gun 10 has a second communication passage 52. The second communication passage 52 is made up of the fourth communication hole 28d, the first supply / discharge passage 17a, the second supply / discharge passage 17b, the third supply / discharge passage 17c of the block supply / discharge passage 17, and the second passage 20b. Therefore, the second communication passage 52 communicates between the second output port 24 and the second pilot chamber 46.

[0039] <Regulating valve> As shown in Fig. 5, the air blow gun 10 is provided with an adjusting valve 60. The adjusting valve 60 has an adjusting valve body 61. The adjusting valve body 61 is columnar. The adjusting valve body 61 is inserted into the insertion hole 16a so as to be able to reciprocate. In this manner, the adjusting valve 60 is provided in the first communication flow path 51.

[0040] The regulating valve element 61 has a main body portion 62 and a valve portion 63. The main body portion 62 is columnar. The valve portion 63 is columnar and protrudes from an end face located at a first end of the main body portion 62. The valve portion 63 has a tapered shape that narrows as it moves away from the first end of the main body portion 62. The main body portion 62 is disposed within the insertion hole 16a. The valve portion 63 enters the regulating valve hole 16h from the insertion hole 16a. The valve portion 63 adjusts the aperture of the regulating valve hole 16h by entering into the regulating valve hole 16h. Therefore, the regulating valve element 61 adjusts the aperture of the regulating valve hole 16h. The regulating valve 60 is a needle valve.

[0041] A portion of the insertion hole 16a is a female threaded hole 16f. The female threaded hole 16f is a portion of the insertion hole 16a that is closer to one side in the longitudinal direction of the flow path forming block 16. A portion of the main body 62 is a male threaded portion 64. The male threaded portion 64 can be threaded into the female threaded hole 16f. The adjustment valve 60 adjusts the amount of insertion of the valve portion 63 into the adjustment valve hole 16h by adjusting the threading position of the male threaded portion 64 relative to the female threaded hole 16f. This adjusts the flow rate of air passing through the adjustment valve hole 16h.

[0042] For example, the more the male thread portion 64 is threaded into the female threaded hole 16f to increase the insertion amount of the valve portion 63 into the adjustment valve hole 16h, the smaller the aperture of the adjustment valve hole 16h. This reduces the flow rate of air passing through the adjustment valve hole 16h. On the other hand, for example, the more the male thread portion 64 is threaded back into the female threaded hole 16f to decrease the insertion amount of the valve portion 63 into the adjustment valve hole 16h, the larger the aperture of the adjustment valve hole 16h. This increases the flow rate of air passing through the adjustment valve hole 16h. Therefore, the adjustment valve 60 adjusts the flow rate of air passing through the adjustment valve hole 16h by mechanically moving the valve portion 63. The nut 65 fixes the adjustment valve element 61 to the insertion hole 16a.

[0043] The adjustment valve 60 adjusts the flow rate of air flowing from the second block communication passage 16d through the adjustment valve hole 16h and the insertion hole 16a to the third block communication passage 16e. The adjustment valve 60 also adjusts the flow rate of air flowing from the third block communication passage 16e through the insertion hole 16a and the adjustment valve hole 16h to the second block communication passage 16d. In this way, the adjustment valve 60 adjusts the flow rate of air flowing through the first communication passage 51.

[0044] An annular seal member 66 is attached to the outer peripheral surface of the main body 62. The seal member 66 prevents air in the insertion hole 16a from leaking out of the flow passage forming block 16 through a gap between the outer peripheral surface of the main body 62 and the inner peripheral surface of the insertion hole 16a.

[0045] <recess> An annular recess 67 is formed on the outer peripheral surface of the main body 62. The recess 67 is formed in a portion of the outer peripheral surface of the main body 62 between the portion where the seal member 66 is attached and the male thread portion 64. In this manner, the recess 67 is formed on the outer peripheral surface of the adjustment valve body 61. The recess 67 extends in the axial direction of the adjustment valve body 61. The recess 67 has a first inner surface 67a, which is a portion of the recess 67 located on the first end side of the insertion hole 16a, and a second inner surface 67b, which is a portion of the recess 67 located on the second end side of the insertion hole 16a. The first inner surface 67a extends annularly in a direction perpendicular to the axial direction of the adjustment valve body 61. The second inner surface 67b extends annularly in a direction perpendicular to the axial direction of the adjustment valve body 61. The first inner surface 67a and the second inner surface 67b face each other in the axial direction of the adjustment valve body 61.

[0046] <Stopper member> A stopper member 68 is provided in the insertion hole 16a. The stopper member 68 is cylindrical. The stopper member 68 is disposed in the recess 67. The stopper member 68 is disposed in the recess 67 with the axial direction of the stopper member 68 perpendicular to the axial direction of the adjustment valve body 61. The stopper member 68 is engaged with the first inner surface 67a to restrict movement of the adjustment valve body 61 in a direction to close the adjustment valve hole 16h, and is engaged with the second inner surface 67b to restrict movement of the adjustment valve body 61 in a direction to open the adjustment valve hole 16h.

[0047] <First and second positions of the first spool valve> 2, when air is discharged from the first pilot chamber 45, the first spool valve 32 switches to the first position, which blocks the flow of air between the communication port 26 and the second output port 24 and allows the flow of air between the second output port 24 and the discharge port 25. At this time, the supply port 22 and the communication port 26 are always in communication with each other via the second communication hole 28b, the communication passage 30, and the third communication hole 28c. Therefore, when the first spool valve 32 is switched to the first position, it can be said that the flow of air between the supply port 22 and the second output port 24 is blocked.

[0048] 6, when air is supplied to the first pilot chamber 45, the first spool valve 32 switches to the second position, which allows air to flow between the communication port 26 and the second output port 24 and blocks air from flowing between the second output port 24 and the exhaust port 25. At this time, the supply port 22 and the communication port 26 are always in communication with each other via the second communication hole 28b, the communication passage 30, and the third communication hole 28c. Therefore, when the first spool valve 32 is switched to the second position, it can be said that air is allowed to flow between the supply port 22 and the second output port 24.

[0049] <Second spool valve in third and fourth positions> As shown in FIG. 2, when the first spool valve 32 is switched to the first position, the second spool valve 33 is switched to the third position, which allows air to flow between the supply port 22 and the first output port 23.

[0050] As shown in FIG. 7, when the first spool valve 32 is switched to the second position, the second spool valve 33 is switched to the fourth position where it blocks the flow of air between the supply port 22 and the first output port 23.

[0051] <Manual valve section> As shown in FIG. 1 , the manual valve unit 12 includes a manual valve block 70 and a cylindrical supply joint 71. The manual valve block 70 has an opposing surface 70a that faces the fourth end surface 184 of the casing body 18. The manual valve block 70 has a first supply passage 72, a valve chamber 73, and a second supply passage 74. One end of the first supply passage 72 is connected to an air supply source 75 via the supply joint 71. The other end of the first supply passage 72 communicates with the valve chamber 73. One end of the second supply passage 74 communicates with the valve chamber 73. The other end of the second supply passage 74 opens to the opposing surface 70a. A second end of the second supply passage 74 communicates with the supply port 22.

[0052] The manual valve unit 12 includes a valve element 76, a biasing spring 77, and a manual shaft 78. The valve element 76 is housed in a valve chamber 73. The manual valve block 70 has a valve seat 79. The valve seat 79 is arranged around the opening of the second supply flow path 74 on the valve chamber 73 side. The valve element 76 is movable toward and away from the valve seat 79. The biasing spring 77 is housed in the valve chamber 73. The biasing spring 77 biases the valve element 76 toward the valve seat 79. When the valve element 76 is seated on the valve seat 79, communication between the valve chamber 73 and the second supply flow path 74 is blocked.

[0053] The manual shaft 78 is retractable relative to the manual valve block 70. When the manual shaft 78 is pushed in a direction to retract into the manual valve block 70 while it is protruding from the manual valve block 70, the manual shaft 78 can press the valve disc 76 in a direction away from the valve seat 79 against the biasing force of the biasing spring 77. When the manual shaft 78 presses the valve disc 76 in a direction away from the valve seat 79 against the biasing force of the biasing spring 77 and the valve disc 76 is separated from the valve seat 79, air is permitted to flow from the first supply flow path 72 to the second supply flow path 74 via the valve chamber 73.

[0054] <First piston pressure surface> 2, the first piston 34 has a first piston pressure surface 81. The first piston pressure surface 81 is an end face of the first piston 34 located on the opposite side from the first spool valve 32. The first piston pressure surface 81 faces the bottom wall of the first piston accommodating recess 19a. The first piston pressure surface 81 receives pressure of pilot air supplied to the first pilot chamber 45 to move the first spool valve 32 from the first position to the second position.

[0055] <First spool pressure surface> The first spool valve 32 has a first spool pressure-receiving surface 82. The first spool pressure-receiving surface 82 is an end face of the first spool valve 32 located on the opposite side from the first piston 34. The first spool pressure-receiving surface 82 receives the pressure of air supplied from the supply port 22 on the side opposite to the first piston 34 in order to move the first spool valve 32 from the second position to the first position.

[0056] <Second piston pressure surface> The second piston 35 has a second piston pressure surface 83. The second piston pressure surface 83 is an end face of the second piston 35 located on the opposite side from the second spool valve 33. The second piston pressure surface 83 faces the bottom wall of the second piston accommodating recess 20a. The second piston pressure surface 83 receives pressure of pilot air supplied to the second pilot chamber 46 to move the second spool valve 33 from the third position to the fourth position. The pressure-receiving area of ​​the second piston pressure surface 83 that receives the pressure of the pilot air in the second pilot chamber 46 is the same as the pressure-receiving area of ​​the first piston pressure surface 81 that receives the pressure of the pilot air in the first pilot chamber 45.

[0057] <Second spool pressure surface> The second spool valve 33 has a second spool pressure-receiving surface 84. The second spool pressure-receiving surface 84 is an end face of the second spool valve 33 located on the opposite side from the second piston 35. The second spool pressure-receiving surface 84 faces the first spool pressure-receiving surface 82. The second spool pressure-receiving surface 84 receives the air supplied from the supply port 22 to move the second spool valve 33 from the fourth position to the third position on the side opposite to the second piston 35. The pressure-receiving area of ​​the second spool pressure-receiving surface 84 that receives the pressure of the air supplied from the supply port 22 is the same as the pressure-receiving area of ​​the first spool pressure-receiving surface 82 that receives the pressure of the air supplied from the supply port 22.

[0058] [Operation of the embodiment] Next, the operation of the embodiment will be described. When the manual shaft 78 of the air blow gun 10 is pressed from a state in which it protrudes from the manual valve block 70 toward a direction in which it retracts into the manual valve block 70, air is intermittently discharged from the discharge port 14.

[0059] Specifically, when the manual shaft 78 is pressed in a direction to be immersed in the manual valve block 70, the manual shaft 78 presses the valve element 76 in a direction to move away from the valve seat 79 against the biasing force of the biasing spring 77. As a result, the valve element 76 is separated from the valve seat 79, and air from the air supply source 75 is supplied to the supply port 22 via the first supply flow path 72, the valve chamber 73, and the second supply flow path 74.

[0060] A portion of the air supplied to the supply port 22 flows through the second communication hole 28b, the communication passage 30, and the third communication hole 28c to the communication port 26. At this time, as shown in FIG. 2, for example, if the first spool valve 32 is moved to the first position and the second spool valve 33 is moved to the third position, a portion of the air supplied to the supply port 22 is output to the first output port 23. Then, the air output from the supply port 22 to the first output port 23 is discharged to the outside from the discharge port 14 via the first communication hole 28a, the first block communicating passage 16c, the second block communicating passage 16d, and the joint mounting hole 16b.

[0061] Furthermore, a portion of the air flowing through the second block communicating passage 16d is supplied as pilot air to the first pilot chamber 45 via the adjusting valve hole 16h, the insertion hole 16a, the third block communicating passage 16e, and the first passage 19b. In this way, pilot air is supplied from the first output port 23 to the first pilot chamber 45 via the first communicating passage 51.

[0062] 6, when pilot air is supplied from the first output port 23 to the first pilot chamber 45 via the first communication passage 51, the first piston pressure-receiving surface 81 receives the pressure of the pilot air supplied to the first pilot chamber 45. This causes the first spool valve 32 to move from the first position to the second position. Then, air flowing from the supply port 22 to the communication port 26 via the second communication hole 28b, the communication passage 30, and the third communication hole 28c is output to the second output port 24.

[0063] As shown in FIG. 7 , the air output to the second output port 24 is supplied as pilot air to the second pilot chamber 46 via the fourth communication hole 28d, the first supply / discharge passage 17a, the second supply / discharge passage 17b, the third supply / discharge passage 17c of the block supply / discharge passage 17, and the second passage 20b. In this manner, pilot air is supplied from the second output port 24 to the second pilot chamber 46 via the second communication passage 52. When pilot air is supplied from the second output port 24 to the second pilot chamber 46 via the second communication passage 52, the second piston pressure-receiving surface 83 receives the pressure of the pilot air supplied to the second pilot chamber 46. This moves the second spool valve 33 from the third position to the fourth position. As a result, the flow of air between the supply port 22 and the first output port 23 is blocked, and the discharge of air to the outside from the discharge port 14 is blocked.

[0064] 8, when the second spool valve 33 is in the fourth position, the flow of air between the supply port 22 and the first output port 23 is blocked, and air is discharged from the first pilot chamber 45 to the outside via the first communication passage 51 and the discharge port 14. Then, the first spool pressure-receiving surface 82 receives the air pressure supplied from the supply port 22, and the first spool valve 32 moves from the second position to the first position.

[0065] This allows air to flow between the second output port 24 and the discharge port 25, and air is discharged from the second pilot chamber 46 to the outside via the second communication passage 52, the second output port 24, and the discharge port 25. Then, the second spool pressure-receiving surface 84 receives pressure from the air supplied from the supply port 22, and as shown in FIG. 2, the second spool valve 33 moves from the fourth position to the third position. As a result, air is allowed to flow between the supply port 22 and the first output port 23. Then, the air output from the supply port 22 to the first output port 23 is discharged to the outside from the discharge port 14 via the first communication hole 28a, the first block communicating passage 16c, the second block communicating passage 16d, and the joint mounting hole 16b.

[0066] The regulating valve 60 adjusts the flow rate of air supplied from the first output port 23 to the first pilot chamber 45 via the first communication flow path 51, thereby adjusting the time until air is filled into the first pilot chamber 45. The regulating valve 60 also adjusts the flow rate of air discharged from the first pilot chamber 45 to the outside via the first communication flow path 51 and the discharge port 14, thereby adjusting the time until air is discharged from the first pilot chamber 45. This adjusts the length of the cycle T1, which is the time from when air is discharged from the discharge port 14 to when the discharge of air from the discharge port 14 is stopped and the discharge of air from the discharge port 14 is resumed. In this way, the regulating valve 60 adjusts the flow rate of air flowing through the first communication flow path 51 to adjust the length of the cycle T1.

[0067] The inventors have found that the value obtained by dividing the pressure-receiving area of ​​the first spool pressure-receiving surface 82 by the pressure-receiving area of ​​the first piston pressure-receiving surface 81 is related to the cut-off time until the discharge of air from the discharge port 14 is blocked. The inventors have also found that the value obtained by dividing the pressure-receiving area of ​​the second spool pressure-receiving surface 84 by the pressure-receiving area of ​​the second piston pressure-receiving surface 83 is related to the cut-off time until the discharge of air from the discharge port 14 is blocked.

[0068] Figure 9 shows the relationship between the on-duty ratio, which is the ratio of the discharge time during which air is discharged to the outside from the discharge port 14 to the blocking time during which the discharge of air from the discharge port 14 is blocked, and the pressure-receiving area of ​​the first piston pressure-receiving surface 81.

[0069] In the following description, the discharge time during which air is discharged to the outside from the discharge port 14 may be simply referred to as the "discharge time." The blocking time during which the discharge of air from the discharge port 14 is blocked may be simply referred to as the "blocking time." Furthermore, the on-duty ratio, which is the ratio between the discharge time during which air is discharged to the outside from the discharge port 14 and the blockage time during which the discharge of air from the discharge port 14 is blocked, may be simply referred to as the "on-duty ratio." The relationship between the on-duty ratio and the pressure-receiving area of ​​the second piston pressure-receiving surface 83 is the same as the relationship between the on-duty ratio and the pressure-receiving area of ​​the first piston pressure-receiving surface 81.

[0070] 10 shows the relationship between the on-duty ratio and the value obtained by dividing the pressure-receiving area of ​​the first spool pressure-receiving surface 82 by the pressure-receiving area of ​​the first piston pressure-receiving surface 81. The relationship between the on-duty ratio and the value obtained by dividing the pressure-receiving area of ​​the second spool pressure-receiving surface 84 by the pressure-receiving area of ​​the second piston pressure-receiving surface 83 is the same as the relationship between the on-duty ratio and the value obtained by dividing the pressure-receiving area of ​​the first spool pressure-receiving surface 82 by the pressure-receiving area of ​​the first piston pressure-receiving surface 81.

[0071] As shown in FIG. 9 , the larger the pressure-receiving area of ​​the first piston pressure surface 81, the smaller the on-duty ratio. Specifically, the larger the pressure-receiving area of ​​the first piston pressure surface 81, the more easily the pressure of the pilot air supplied to the first pilot chamber 45 acts on the first piston pressure surface 81. As a result, the first spool valve 32 moves more easily from the first position to the second position. Furthermore, the larger the pressure-receiving area of ​​the second piston pressure surface 83, the more easily the pressure of the pilot air supplied to the second pilot chamber 46 acts on the second piston pressure surface 83. As a result, the second spool valve 33 moves more easily from the third position to the fourth position. This lengthens the blocking time during which the discharge of air from the discharge port 14 is blocked. Thus, the larger the pressure-receiving areas of the first piston pressure surface 81 and the second piston pressure surface 83, the longer the blocking time during which the discharge of air from the discharge port 14 is blocked, and therefore the smaller the on-duty ratio.

[0072] 10, the on-duty ratio increases as the value obtained by dividing the pressure-receiving area of ​​the first spool pressure surface 82 by the pressure-receiving area of ​​the first piston pressure surface 81 increases. Specifically, the smaller the pressure-receiving area of ​​the first spool pressure surface 82 and the larger the pressure-receiving area of ​​the first piston pressure surface 81, the easier it is for the first spool valve 32 to move from the first position to the second position and the more difficult it is for it to move from the second position to the first position. Furthermore, the smaller the pressure-receiving area of ​​the second spool pressure surface 84 and the larger the pressure-receiving area of ​​the second piston pressure surface 83, the easier it is for the second spool valve 33 to move from the third position to the fourth position and the more difficult it is for it to move from the fourth position to the third position. In this way, the on-duty ratio is adjusted based on the value obtained by dividing the pressure-receiving area of ​​the first spool pressure-receiving surface 82 by the pressure-receiving area of ​​the first piston pressure-receiving surface 81, and the value obtained by dividing the pressure-receiving area of ​​the second spool pressure-receiving surface 84 by the pressure-receiving area of ​​the second piston pressure-receiving surface 83.

[0073] FIG. 11(a) shows an air blow gun 10 with an on-duty ratio of 50% and a frequency adjusted to 5 Hz (5 cycles / second) intermittently discharging air from the discharge port 14. FIG. 11(b) shows an air blow gun 10 with an on-duty ratio of 33% and a frequency adjusted to 5 Hz (5 cycles / second) intermittently discharging air from the discharge port 14. FIG. 11(c) shows an air blow gun 10 with an on-duty ratio of 25% and a frequency adjusted to 5 Hz (5 cycles / second) intermittently discharging air from the discharge port 14. FIG. 11(d) shows an air blow gun 10 with an on-duty ratio of 25% and a frequency adjusted to 15 Hz (15 cycles / second) intermittently discharging air from the discharge port 14. Figure 11(e) shows the state in which air is intermittently discharged from the discharge port 14 in an air blow gun 10 with an on-duty ratio of 50% and a frequency adjusted to 15 Hz (15 cycles / second).

[0074] As shown in FIGS. 11(a) to 11(e), the pressure-receiving areas of the first piston pressure surface 81, the first spool pressure surface 82, the second piston pressure surface 83, and the second spool pressure surface 84 are preset so as to obtain a desired shut-off time. As a result, the discharge time during which air is discharged from the discharge port 14 is the time from when air is discharged from the discharge port 14 until the discharge of air from the discharge port 14 is stopped and the discharge of air from the discharge port 14 is resumed, excluding the shut-off time. As a result, the on-duty ratio, which is the ratio of the discharge time during which air is discharged from the discharge port 14 to the shut-off time during which the discharge of air from the discharge port 14 is stopped, can be adjusted. Furthermore, by adjusting the flow rate of air flowing through the first communication flow path 51 using the adjustment valve 60, the length of the cycle T1 can be set to a desired length. As a result, the frequency of the air blow gun 10 can be adjusted.

[0075] [Effects of the embodiment] The above embodiment can provide the following effects. (1) The inventors have found that the value obtained by dividing the pressure-receiving area of ​​the first spool pressure-receiving surface 82 by the pressure-receiving area of ​​the first piston pressure-receiving surface 81 is related to the cut-off time during which the discharge of air from the discharge port 14 is cut off. The inventors have also found that the value obtained by dividing the pressure-receiving area of ​​the second spool pressure-receiving surface 84 by the pressure-receiving area of ​​the second piston pressure-receiving surface 83 is related to the cut-off time during which the discharge of air from the discharge port 14 is cut off. Therefore, the pressure-receiving areas of the first piston pressure-receiving surface 81, the first spool pressure-receiving surface 82, the second piston pressure-receiving surface 83, and the second spool pressure-receiving surface 84 are each set in advance so as to obtain a desired cut-off time. As a result, the discharge time during which air is discharged from the discharge port 14 is the time from when air is discharged from the discharge port 14 until the discharge of air from the discharge port 14 is cut off and the discharge of air from the discharge port 14 is resumed, excluding the cut-off time. As a result, it is possible to adjust the on-duty ratio, which is the ratio between the discharge time during which air is discharged to the outside from the discharge port 14 and the blocking time during which the discharge of air from the discharge port 14 is blocked. In this way, it is possible to obtain the desired discharge time and blocking time while avoiding unintentional changes to the length of the cycle T1, which is the time from when air is discharged from the discharge port 14 to when the discharge of air from the discharge port 14 is blocked and then the discharge of air from the discharge port 14 is started again.

[0076] (2) The first communication flow path 51 is provided with an adjustment valve 60. The adjustment valve 60 adjusts the flow rate of air flowing through the first communication flow path 51 in order to adjust the length of a cycle T1, which is the time from when air is discharged from the discharge port 14 until the discharge of air from the discharge port 14 is stopped and then when air is discharged again from the discharge port 14. This allows the length of the cycle T1 to be set to a desired length, making it possible to perform blowing that is appropriate for the blowing target.

[0077] (3) A recess 67 extending in the axial direction of the adjusting valve element 61 is formed on the outer peripheral surface of the adjusting valve element 61. A stopper member 68 is provided within the insertion hole 16a. The stopper member 68 is engaged with a portion of the recess 67 located on the first end side of the insertion hole 16a, thereby restricting further movement of the adjusting valve element 61 in a direction to close the adjusting valve hole 16h. This prevents the adjusting valve element 61 from completely closing the adjusting valve hole 16h. Meanwhile, the stopper member 68 is engaged with a portion of the recess 67 located on the second end side of the insertion hole 16a, thereby restricting further movement of the adjusting valve element 61 in a direction to open the adjusting valve hole 16h. This prevents the adjusting valve hole 16h from being opened too widely. This prevents the air blow gun 10 from operating normally.

[0078] (4) The first pilot chamber 45 has a first piston chamber 36 in which the first piston 34 reciprocates and a first expansion chamber 41 that communicates with the first piston chamber 36. The second pilot chamber 46 has a second piston chamber 37 in which the second piston 35 reciprocates and a second expansion chamber 42 that communicates with the second piston chamber 37. This allows the volume of the first pilot chamber 45 to be larger than when the first pilot chamber 45 does not have the first expansion chamber 41. Furthermore, the volume of the second pilot chamber 46 can be larger than when the second pilot chamber 46 does not have the second expansion chamber 42. Therefore, the charging time of pilot air supplied to the first pilot chamber 45 and the second pilot chamber 46 can be extended, preventing the first spool valve 32 and the second spool valve 33 from reciprocating excessively quickly. As a result, it is possible to avoid the process of discharging air from the discharge port 14, then stopping the discharge of air from the discharge port 14, and then discharging air from the discharge port 14 again being repeated too frequently, thereby making it easier to save energy on air.

[0079] (5) According to the present embodiment, a spring for reciprocating the first spool valve 32 and the second spool valve 33 is not required, and therefore, unlike the air blow gun 10 provided with such a spring, there is no need to consider the durability of the spring. Therefore, even if the air blow gun 10 is operated frequently, it can be used for a long time.

[0080] [Example of change] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0081] In the embodiment, the adjustment valve 60 may be provided in the second communication flow path 52 instead of the first communication flow path 51. In this case, an adjustment valve hole 16h is formed in a portion of the second communication flow path 52. The adjustment valve element 61 adjusts the aperture of the adjustment valve hole 16h, which forms a portion of the second communication flow path 52. In short, it is sufficient that the adjustment valve 60 that adjusts the flow rate of air flowing through the first communication flow path 51 or the second communication flow path 52 is provided in the first communication flow path 51 or the second communication flow path 52. The adjustment valve element 61 adjusts the aperture of the adjustment valve hole 16h, which forms a portion of the first communication flow path 51 or the second communication flow path 52. It is sufficient that the adjustment valve 60 can adjust the length of the cycle T1, which is the time from when air is discharged from the discharge port 14, until the discharge of air from the discharge port 14 is stopped and the discharge of air from the discharge port 14 is resumed.

[0082] In the embodiment, the air blow gun 10 may be configured such that the adjustment valve 60 is not provided in the first communication flow path 51. In the embodiment, the recess 67 does not have to be formed on the outer circumferential surface of the adjustment valve body 61. Furthermore, the stopper member 68 does not have to be provided inside the insertion hole 16a.

[0083] In the embodiment, the first pilot chamber 45 does not necessarily have to have the first expansion chamber 41. In the embodiment, the second pilot chamber 46 does not necessarily have to have the second expansion chamber 42.

[0084] In the embodiment, the pressure receiving area of ​​the first piston pressure receiving surface 81 and the pressure receiving area of ​​the second piston pressure receiving surface 83 may be different. In the embodiment, the pressure receiving area of ​​the first spool pressure receiving surface 82 and the pressure receiving area of ​​the second spool pressure receiving surface 84 may be different.

[0085] In the embodiment, the first piston 34 is not limited to a disk shape, and may be, for example, an elliptical plate shape or an oblong plate shape. In short, the shape of the first piston 34 is not particularly limited.

[0086] In the embodiment, the second piston 35 is not limited to a disk shape, and may be, for example, an elliptical plate shape or an oblong plate shape. In short, the shape of the second piston 35 is not particularly limited.

[0087] In the embodiment, the air blow gun 10 may be provided with an electromagnetic valve unit that electrically controls the opening and closing of the valve element 76, instead of the manual valve unit 12. [Explanation of symbols]

[0088] 10...air blow gun which is a pulse air generator, 13...body, 14...discharge port, 16a...insertion hole, 16h...regulating valve hole, 21...valve hole, 22...supply port, 23...first output port, 24...second output port, 25...discharge port, 32...first spool valve, 33...second spool valve, 34...first piston, 35...second piston, 36...first piston chamber, 37...second piston chamber, 41...first expansion chamber, 42...second expansion chamber, 45...first pilot chamber, 46...second pilot chamber, 51...first communicating flow path, 52...second communicating flow path, 60...regulating valve, 61...regulating valve body, 67...recess, 68...stopper member, 81...first piston pressure receiving surface, 82...first spool pressure receiving surface, 83...second piston pressure receiving surface, 84...second spool pressure receiving surface.

Claims

1. A pulse air generator that intermittently discharges air from a discharge port, Body and a valve hole formed in the body; a first spool valve and a second spool valve that are accommodated in the valve hole so as to be able to reciprocate and are arranged adjacent to each other in the axial direction of the valve hole; a supply port, a first output port, a second output port, and a discharge port formed in the body and communicating with the valve hole, respectively; a first piston provided at an end of the first spool valve and moving integrally with the first spool valve; a second piston provided at an end of the second spool valve and moving integrally with the second spool valve; a first pilot chamber to which pilot air for moving the first piston is supplied and discharged; a second pilot chamber to which pilot air for moving the second piston is supplied and discharged; a first communication passage connected to the discharge port and communicating between the first output port and the first pilot chamber; a second communication passage communicating the second output port and the second pilot chamber, When air is discharged from the first pilot chamber, the first spool valve switches to a first position where the flow of air is blocked between the supply port and the second output port and the flow of air is permitted between the second output port and the exhaust port, and when air is supplied to the first pilot chamber, the first spool valve switches to a second position where the flow of air is permitted between the supply port and the second output port and the flow of air is blocked between the second output port and the exhaust port, the second spool valve is switched to a third position allowing air to flow between the supply port and the first output port when the first spool valve is switched to the first position, and is switched to a fourth position blocking air from flowing between the supply port and the first output port when the first spool valve is switched to the second position; the first piston has a first piston pressure-receiving surface that receives pressure of pilot air supplied to the first pilot chamber to move the first spool valve from the first position to the second position; the first spool valve has a first spool pressure-receiving surface that receives pressure of air supplied from the supply port on the side opposite to the first piston in order to move the first spool valve from the second position to the first position; the second piston has a second piston pressure-receiving surface that receives pressure of pilot air supplied to the second pilot chamber to move the second spool valve from the third position to the fourth position, the second spool valve has a second spool pressure-receiving surface that receives pressure of air supplied from the supply port on the side opposite to the second piston in order to move the second spool valve from the fourth position to the third position, an on-duty ratio, which is the ratio between a discharge time during which air is discharged to the outside from the discharge port and a cut-off time during which the discharge of air from the discharge port is cut off, is adjusted based on a value obtained by dividing a pressure-receiving area of ​​the first spool pressure-receiving surface by a pressure-receiving area of ​​the first piston pressure-receiving surface and a value obtained by dividing a pressure-receiving area of ​​the second spool pressure-receiving surface by a pressure-receiving area of ​​the second piston pressure-receiving surface.

2. 2. The pulse air generator according to claim 1, wherein the first communication flow path or the second communication flow path is provided with an adjustment valve that adjusts the flow rate of air flowing through the first communication flow path or the second communication flow path, in order to adjust the length of a cycle that is a time period from when air is discharged from the discharge port until the discharge of air from the discharge port is stopped and the discharge of air from the discharge port is started again.

3. the regulating valve has a columnar regulating valve body that regulates the opening degree of a regulating valve hole that forms a part of the first communication flow path or the second communication flow path, The body has an insertion hole formed therein, the insertion hole having a first end that opens to an outer surface of the body and a second end that communicates with the adjustment valve hole, The adjustment valve body is inserted into the insertion hole so as to be capable of reciprocating motion, a recess extending in the axial direction of the adjustment valve body is formed on the outer peripheral surface of the adjustment valve body, A stopper member is provided in the insertion hole, 3. The pulse air generator according to claim 2, wherein the stopper member is engaged with a portion of the recess located on a first end side of the insertion hole, thereby restricting movement of the adjustment valve body in a direction to close the adjustment valve hole, and is engaged with a portion of the recess located on a second end side of the insertion hole, thereby restricting movement of the adjustment valve body in a direction to open the adjustment valve hole.

4. The first pilot chamber is a first piston chamber in which the first piston reciprocates; a first expansion chamber communicating with the first piston chamber, The second pilot chamber is a second piston chamber in which the second piston reciprocates; 4. The pulse air generator according to claim 1, further comprising: a second expansion chamber communicating with the second piston chamber.

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