JP7736558B2 - air pump - Google Patents

Description

The present invention relates to an air pump in which air is discharged from a discharge hole in a cylinder.

In the pump described in Patent Document 1 below, a seal member is disposed between the right and left side walls of the plunger, and a slit is provided in the seal member. When the drive means moves the plunger to the right, the seal member seals between the pump cylinder and the left side wall of the plunger, sealing the gap between the pump cylinder and the plunger, allowing oil to be discharged from the fluid passage of the pump cylinder. On the other hand, when the drive means moves the plunger to the left, the seal member does not seal between the pump cylinder and the right side wall of the plunger via the slit, and the gap between the pump cylinder and the plunger is not sealed.

In such pumps, it is desirable to improve the durability of the sealing members, especially when air is discharged from the fluid passages of the pump cylinder.

Japanese Patent Application Publication No. 8-4650

In consideration of the above, the present invention aims to provide an air pump that can improve the durability of the sealing member.

The air pump of a first aspect of the present invention comprises a cylinder having a discharge hole on one side; a piston movable within the cylinder, having one side and another side, and having a passage hole on the one side; a seal member disposed between the one side and the other side; and a moving device such that when the piston is moved to one side, the seal member seals between the cylinder and the other side, thereby sealing the gap between the cylinder and the piston and allowing air to be discharged through the discharge hole, and when the piston is moved to the other side, the seal member does not seal the passage hole, resulting in an open gap between the cylinder and the piston.

The air pump of the second aspect of the present invention is the air pump of the first aspect of the present invention, further comprising a communication hole provided on the other side portion that is sealed by the sealing member when the moving device moves the piston to one side.

The air pump of the third aspect of the present invention is the air pump of the first or second aspect of the present invention, wherein the outer periphery of the one side portion is capable of contacting the cylinder.

The air pump of the fourth aspect of the present invention is an air pump of any one of the first to third aspects of the present invention, wherein the outer periphery of the other side portion is capable of contacting the cylinder.

The air pump of a fifth aspect of the present invention is an air pump according to any one of the first to fourth aspects of the present invention, further comprising a protrusion that is provided on the piston and protrudes toward the sealing member, forming a communication passage between the piston and the sealing member that connects one side of the piston to the other side when the movement device moves the piston to the other side.

The sixth aspect of the air pump of the present invention is the air pump of any one of the first to fifth aspects of the present invention, wherein the cross section of the sealing member is circular.

The air pump of the first aspect of the present invention has a discharge hole on one side of the cylinder, allowing a piston to move within the cylinder. The piston also has one side and another side, and a seal member is disposed between the one side and the other side of the piston. Furthermore, when the moving device moves the piston to one side, the seal member seals the gap between the cylinder and the other side of the piston, sealing the gap between the cylinder and the piston, allowing air to be discharged from the discharge hole of the cylinder.

Here, a passage hole is provided on one side of the piston, and when the movement device moves the piston to the other side, the sealing member does not seal the passage hole, and the gap between the cylinder and the piston is not sealed. Therefore, when the movement device moves the piston to the other side, the passage hole in the piston does not seal the gap between the cylinder and the piston, which allows the shape of the sealing member to be simplified and improves the durability of the sealing member.

In the air pump of the second aspect of the present invention, a communication hole is provided on the other side of the piston, and a sealing member seals the communication hole when the moving device moves the piston to one side. Therefore, when the moving device moves the piston to the other side, air can be effectively sucked into the one side of the piston through the communication hole.

In the air pump of the third aspect of the present invention, the outer periphery of one side of the piston is allowed to come into contact with the cylinder. This allows the piston to move appropriately within the cylinder.

In the air pump of the fourth aspect of the present invention, the outer periphery of the other side of the piston is able to come into contact with the cylinder. This allows the piston to move appropriately within the cylinder.

In the air pump of the fifth aspect of the present invention, when the movement device moves the piston to the other side, the circumferential surface of the communication passage that connects one side of the piston to the other is formed between the protruding portion of the piston and the seal member, and the protruding portion protrudes toward the seal member. Therefore, the protruding portion can suppress sudden fluctuations in the distance between the seal member and the piston in the communication passage, allowing air to be effectively sucked into one side of the piston via the communication passage.

In the air pump of the sixth aspect of the present invention, the cross section of the sealing member is circular. This effectively simplifies the shape of the sealing member, effectively improving the durability of the sealing member.

1 is an exploded perspective view of an air pump according to an embodiment of the present invention, viewed obliquely from the front left. 1A and 1B are diagrams showing the inside of an air pump according to an embodiment of the present invention, where FIG. 1A is a top view seen from above, and FIG. 1B is a perspective view seen from the rear diagonally left. 1A to 1D are diagrams showing a piston and an O-ring of an air pump according to an embodiment of the present invention, where 1A is a perspective view seen from the rear left, 1B is a perspective view seen from the front, 1C is a front view seen from the front, 1D is a rear view seen from the rear, and 1E is a perspective view seen from the left showing a rod of the air pump according to an embodiment of the present invention. (A) to (F) are top views showing the inside of an air pump according to an embodiment of the present invention, where (A) shows the piston at its top dead center, (B) shows the first stage in which the piston is moved rearward, (C) shows the second stage in which the piston is moved rearward, (D) shows the piston at its bottom dead center, (E) shows the first stage in which the piston is moved forward, and (F) shows the second stage in which the piston is moved forward. (A) to (C) are cross-sectional views from the left showing the cylinder, piston, and O-ring of an air pump according to an embodiment of the present invention, where (A) shows the piston being moved rearward, (B) shows the piston being moved rearward in detail, and (C) shows the piston being moved forward in detail.

Figure 1 shows an exploded perspective view of an air pump 10 according to an embodiment of the present invention, viewed diagonally from the front left. Furthermore, Figure 2(A) shows a top view of the interior of the air pump 10, viewed from above, and Figure 2(B) shows a perspective view of the interior of the air pump 10, viewed diagonally from the rear left. In the drawings, the front of the air pump 10 is indicated by arrow FR, the right of the air pump 10 is indicated by arrow RH, and the top of the air pump 10 is indicated by arrow UP.

The air pump 10 according to this embodiment is installed in, for example, a vehicle (automobile), and the air pump 10 discharges (presses out) air from the discharge hole 24B described below, which is then sprayed through a tube and from a nozzle at the tip of the tube onto the lens or mirror of the vehicle's camera, thereby cleaning the lens or mirror.

As shown in Figures 1, 2(A) and 2(B), the air pump 10 is provided with a roughly rectangular box-shaped case 12, which is composed of an upper case 12A and a lower case 12B assembled together. The case 12 is roughly L-shaped when viewed from above, with the rear portion protruding to the left and the left portion of the case 12 open to the front.

A motor 14 serving as a movement device is fixed within the right portion of the case 12, with its output shaft 14A extending rearward. A worm 16 serving as a first gear is coaxially fixed to the output shaft 14A, and when the motor 14 is driven, the worm 16 rotates integrally with the output shaft 14A. A worm wheel 18 serving as a second gear is located to the left of the worm 16, and is rotatably supported within the case 12 with its axial direction aligned vertically. The worm wheel 18 is meshed with the worm 16, restricting its rotation; when the worm 16 rotates, the worm wheel 18 rotates.

A helical gear 20, which serves as a third gear and a driving member, is located to the left of the worm wheel 18. The helical gear 20 is rotatably supported within the left portion of the case 12 with its axial direction oriented vertically. The helical gear 20 is meshed with the worm wheel 18, and when the worm wheel 18 rotates, the helical gear 20 rotates. A cylindrical support shaft 20A is integrally formed at the radially middle portion of the helical gear 20, and the support shaft 20A protrudes upward from the helical gear 20.

A long, plate-shaped rod 22 (see Figure 3(E)) is positioned above the helical gear 20 as a connecting member, and the rear end of the rod 22 is rotatably supported on the support shaft 20A of the helical gear 20. A circular connecting hole 22A is formed through the front end of the rod 22, and a roughly triangular mating hole 22B is formed through the rod 22 behind the connecting hole 22A.

A generally cylindrical cylinder 24 with a bottom is attached to the front side of the left side of the case 12, with the axial direction of the cylinder 24 extending in the front-to-rear direction. The interior of the cylinder 24 is open to the rear and is connected to the interior of the left side of the case 12. A generally cylindrical discharge tube 24A is integrally formed coaxially with the front wall (bottom wall) of the cylinder 24, and the discharge tube 24A extends forward from the cylinder 24. The interior of the discharge tube 24A forms a discharge hole 24B which is connected to the interior of the cylinder 24, and the above-mentioned tube is connected to the discharge tube 24A.

A roughly cylindrical piston 26 is fitted coaxially within the cylinder 24. The piston 26 is movable forward (one side) and backward (the other side) within the cylinder 24, and forms a pressure chamber 28 on the front side of the cylinder 24.

A connecting piece 30 (see Figure 3(A)) with an L-shaped cross section is integrally formed on the rear side of the piston 26, with the lower portion of the connecting piece 30 protruding rearward from the piston 26. The rear portion of the connecting piece 30 forms a cylindrical connecting shaft 30A, which protrudes upward. A roughly triangular plate-shaped locking portion 30B is integrally formed on the upper end of the connecting shaft 30A, and the locking portion 30B protrudes to the left from the connecting shaft 30A.

The connecting shaft 30A and the locking portion 30B are adapted to fit into the connecting hole 22A and the mating hole 22B of the rod 22, respectively. The connecting hole 22A and the mating hole 22B are fitted into the connecting shaft 30A and the locking portion 30B from above, respectively, and are then moved downward to the locking portion 30B, whereby the connecting hole 22A is rotatably fitted into the connecting shaft 30A, and the rod 22 is rotatably supported by the connecting shaft 30A. Therefore, the rod 22 connects the helical gear 20 (support shaft 20A) and the piston 26 (connection shaft 30A). Rotating the helical gear 20 causes the rod 22 to rotate relative to the support shaft 20A and the connecting shaft 30A while reciprocating forward and backward, causing the piston 26 to reciprocate forward and backward within the cylinder 24 (see Figures 4A-4F). The position to which the piston 26 is moved furthest forward is the top dead center of the piston 26 (position in Figure 4(A)), and the position to which the piston 26 is moved furthest rearward is the bottom dead center of the piston 26 (position in Figure 4(D)). Furthermore, when the piston 26 is moved back and forth forward and rearward by the rod 22, it is never positioned in a rotational position where the fitting hole 22B fits into the locking portion 30B, so the upward movement of the rod 22 is locked by the locking portion 30B, preventing the rod 22 (connecting hole 22A) from falling off the piston 26 (connecting shaft 30A).

A substantially circular front plate 32 (see Figures 3B and 3C) is coaxially mounted on the front end of the piston 26 as one side. The front plate 32 has an outer diameter slightly smaller than the inner diameter of the cylinder 24 and is capable of contacting the inner peripheral surface of the cylinder 24. A predetermined number of substantially elongated rectangular through holes 32A are formed through the outer periphery of the front plate 32, and the predetermined number of through holes 32A are arranged at equal intervals around the periphery of the front plate 32. The longitudinal direction of the through holes 32A is in the radial direction of the front plate 32, and the radially inner end surface of the front plate 32 is convexly curved, and the through holes 32A are open radially outward from the front plate 32.

A roughly circular rear plate 34 (see Figures 3A and 3D) is coaxially mounted on the rear end of the piston 26 as the other side, and the outer diameter of the rear plate 34 is the same as the outer diameter of the front plate 32. Therefore, the outer diameter of the rear plate 34 is slightly smaller than the inner diameter of the cylinder 24, allowing the rear plate 34 to come into contact with the inner circumferential surface of the cylinder 24. A predetermined number of roughly semicircular communication holes 34A are formed through the outer periphery of the rear plate 34, and the predetermined number of communication holes 34A are arranged at equal intervals around the circumferential direction of the rear plate 34. The circumferential surface of the communication holes 34A is convexly curved, and the communication holes 34A open radially outward from the rear plate 34. The maximum radial dimension of the communication holes 34A in the rear plate 34 is smaller than the maximum radial dimension of the through holes 32A in the front plate 32, and the maximum circumferential dimension of the communication holes 34A in the rear plate 34 is smaller than the maximum circumferential dimension of the through holes 32A in the front plate 32. The number of communication holes 34A is greater than the number of through holes 32A, and the spacing between the communication holes 34A in the circumferential direction of the rear plate 34 is smaller than the spacing between the through holes 32A in the circumferential direction of the front plate 32.

A generally cylindrical intermediate shaft 36 (see FIG. 5A) is coaxially disposed between the front plate 32 and rear plate 34 of the piston 26 as an intermediate portion. The intermediate shaft 36 is integrally formed with the front plate 32 and rear plate 34, forming the front plate 32 and rear plate 34 as a single unit. The diameter (minimum diameter) of the intermediate shaft 36 is the same as the diameter of the front plate 32 at the position where the radially inner end of the through hole 32A in the front plate 32 is located. An annular protrusion 36A is integrally formed coaxially on the outer periphery of the intermediate shaft 36. The protrusion 36A extends from near the front end to the rear end of the intermediate shaft 36 and is integral with the rear plate 34. The cross section (cross section perpendicular to the circumferential direction) of the protrusion 36A is generally triangular, and the outer peripheral surface of the protrusion 36A is inclined radially outward as it extends rearward, with the rear end of the outer peripheral surface of the protrusion 36A being located radially near the communication hole 34A of the rear plate 34. The outer peripheral surface of the protrusion 36A is curved concavely in the axial direction (front-to-rear direction) of the intermediate shaft 36, and the outer peripheral surface of the protrusion 36A is smoothly connected to the outer peripheral surface of the intermediate shaft 36 on its front side (radially inward) and smoothly connected to the front surface of the rear plate 34 on its rear side (radially outward).

A circular O-ring 38 is disposed between the front plate 32 and rear plate 34 of the piston 26 as a sealing member. The O-ring 38 is made of rubber, providing elasticity and sealing properties, and has a circular cross section (cross section perpendicular to the circumferential direction). The inner diameter of the O-ring 38 is smaller than the outer diameters of the front plate 32 and rear plate 34. The O-ring 38 is temporarily elastically expanded to allow the front plate 32 or rear plate 34 to pass radially inside, thereby being disposed between the front plate 32 and rear plate 34. The outer diameter of the O-ring 38 (outer diameter before being disposed in the cylinder 24) is larger than the inner diameter of the cylinder 24. The O-ring 38 is pressed against the inner circumferential surface of the cylinder 24 and elastically contracts radially inward. Therefore, when the O-ring 38 moves forward or rearward, it slides against the inner circumferential surface of the cylinder 24.

The longitudinal dimension of the O-ring 38 (the diameter of a cross section perpendicular to the circumferential direction) is smaller than the longitudinal separation between the front plate 32 and the rear plate 34. When the piston 26 is moved forward, the O-ring 38 abuts against the rear plate 34 and is moved forward by the rear plate 34 while sliding against the inner surface of the cylinder 24 (see Figure 5(C)). When the piston 26 is moved rearward, the O-ring 38 abuts against the front plate 32 and is moved rearward by the front plate 32 while sliding against the inner surface of the cylinder 24 (see Figure 5(B)).

The radius of the cross section (cross section perpendicular to the circumferential direction) of the O-ring 38 is larger than the distance between the inner surface of the cylinder 24 and the radially inner end of the rear plate 34 of the communication hole 34A. When the piston 26 is moved forward, the O-ring 38 abuts radially inward from the communication hole 34A in the rear plate 34, sealing the gap between the cylinder 24 and the rear plate 34 (and the communication hole 34A). The radius of the cross section (cross section perpendicular to the circumferential direction) of the O-ring 38 is smaller than the distance between the inner surface of the cylinder 24 and the radially inner end of the through hole 32A in the front plate 32. When the piston 26 is moved rearward, the O-ring 38 abuts radially outward from the front plate 32 rather than from the radially inner end of the through hole 32A in the front plate 32, not sealing the gap between the cylinder 24 and the front plate 32 (through hole 32A).

The inner diameter of the O-ring 38 is larger than the minimum diameter (diameter at the front end) of the protruding portion 36A on the intermediate shaft 36 of the piston 26, and smaller than the maximum diameter (outer diameter at the rear end) of the protruding portion 36A. When the piston 26 is moved rearward, a communication passage 40 is formed between the O-ring 38 and the circumferential surface of the intermediate shaft 36 (including the outer surface of the protruding portion 36A) and the front surface of the rear plate 34.

Next, we will explain the operation of this embodiment.

In the air pump 10 configured as described above, when the motor 14 is driven and the output shaft 14A, worm 16, worm wheel 18, and helical gear 20 are rotated, the rod 22 is moved back and forth forward and backward, and the piston 26 is moved back and forth forward and backward within the cylinder 24 (see Figures 4A to 4F).

As the piston 26 moves rearward from top dead center to bottom dead center, the O-ring 38 abuts against the front plate 32 of the piston 26 and is moved rearward by the front plate 32 while sliding against the inner circumferential surface of the cylinder 24 (see Figures 4A-4D and 5B). Furthermore, the O-ring 38 abuts against the radially outer side of the front plate 32 rather than the radially inner end of the through hole 32A in the piston 26, thereby not sealing the gap between the cylinder 24 and the front plate 32 (through hole 32A and the gap between the front plate 32 and the cylinder 24). As a result, air is drawn into the pressurized chamber 28 of the cylinder 24 (forward of the piston 26) through the communication hole 34A in the rear plate 34 of the piston 26, the gap between the rear plate 34 and the cylinder 24, the communication passage 40, the through hole 32A, and the gap between the front plate 32 and the cylinder 24. This prevents air from being drawn into the pressurized chamber 28 from the discharge tube 24A (discharge hole 24B) of the cylinder 24, eliminating the need to provide a check valve in the discharge hole 24B and reducing the number of parts.

When the piston 26 moves forward from bottom dead center to top dead center, the O-ring 38 abuts against the rear plate 34 of the piston 26 and is moved forward by the rear plate 34 while sliding against the inner surface of the cylinder 24 (see Figures 4D-4F and 4A and 5C). Furthermore, the sliding resistance of the O-ring 38 against the inner surface of the cylinder 24 and the air pressure from the front and radially inward force causes the O-ring 38 to abut (closely contact) radially inward from the communication hole 34A of the rear plate 34 and against the inner surface of the cylinder 24, sealing the gap between the cylinder 24 and the rear plate 34 (the gap between the communication hole 34A and the cylinder 24 and the rear plate 34). Therefore, even if the air in the pressurized chamber 28 passes through the passage hole 32A in the front plate 32 of the piston 26 and the gap between the front plate 32 and the cylinder 24, it does not flow out to the rear side of the piston 26 from between the cylinder 24 and the rear plate 34, so the pressure of the air in the pressurized chamber 28 increases and the air in the pressurized chamber 28 is discharged (pressed out) through the discharge hole 24B of the cylinder 24. Also, because no check valve is provided in the discharge hole 24B as described above, no resistance from the check valve acts on the air being discharged from the discharge hole 24B.

Here, a through hole 32A is provided in the front plate 32 of the piston 26, and when the piston 26 is moved rearward, the O-ring 38 does not seal the through hole 32A, and the gap between the cylinder 24 and the piston 26 is not sealed. Therefore, when the piston 26 is moved rearward, the through hole 32A of the piston 26 does not seal the gap between the cylinder 24 and the piston 26, eliminating the need to provide a hole in the O-ring 38 to prevent the gap from being sealed between the cylinder 24 and the piston 26. This simplifies the shape of the O-ring 38 and improves the durability of the O-ring 38.

In addition, the cross section of the O-ring 38 (a cross section perpendicular to the circumferential direction) is circular, and the entire circumferential surface of the O-ring 38 is curved. This effectively simplifies the shape of the O-ring 38, effectively improving the durability of the O-ring 38.

Furthermore, in the piston 26, the cross section of the through hole 32A in the front plate 32 (cross section perpendicular to the axis of the front plate 32) is larger than the cross section of the communication hole 34A in the rear plate 34 (cross section perpendicular to the axis of the rear plate 34). Therefore, when the piston 26 is moved rearward, the O-ring 38 can appropriately open the through hole 32A, allowing air to be effectively sucked into the pressurized chamber 28 of the cylinder 24 through the through hole 32A.

In addition, a communication hole 34A is provided in the rear plate 34 of the piston 26, and when the piston 26 is moved forward, an O-ring 38 seals the communication hole 34A, sealing the gap between the cylinder 24 and the rear plate 34. Therefore, when the piston 26 is moved rearward, air can be effectively sucked into the pressure chamber 28 of the cylinder 24 not only through the gap between the cylinder 24 and the rear plate 34, but also via the communication hole 34A.

Furthermore, the piston 26 has a greater number of communication holes 34A than the number of through holes 32A. Therefore, when the piston 26 is moved rearward, air can be more effectively drawn into the pressure chamber 28 of the cylinder 24 through the communication holes 34A.

In addition, the peripheral surface of the communication passage 40 between the intermediate shaft 36 of the piston 26 and the O-ring 38 is formed by the protruding portion 36A of the intermediate shaft 36, with the protruding portion 36A protruding toward the O-ring 38. As a result, when the piston 26 is moved rearward, the protruding portion 36A prevents the distance between the O-ring 38 and the intermediate shaft 36 in the communication passage 40 from changing suddenly, allowing air to be effectively sucked into the pressurized chamber 28 of the cylinder 24 via the communication passage 40.

Furthermore, the O-ring 38 is curved convexly toward the protruding portion 36A, and the outer surface of the protruding portion 36A is curved concavely away from the O-ring 38. As a result, when the piston 26 moves rearward, the protruding portion 36A effectively prevents the distance between the O-ring 38 and the intermediate shaft 36 in the communicating passage 40 from changing suddenly, allowing air to be more effectively sucked into the pressurized chamber 28 of the cylinder 24 via the communicating passage 40.

In addition, the outer periphery of the front plate 32 of the piston 26 is able to come into contact with the inner periphery of the cylinder 24. This prevents the axial direction of the piston 26 from tilting relative to the axial direction of the cylinder 24, allowing the piston 26 to move appropriately within the cylinder 24.

Furthermore, the outer periphery of the rear plate 34 of the piston 26 is able to come into contact with the inner periphery of the cylinder 24. This further prevents the axial direction of the piston 26 from tilting relative to the axial direction of the cylinder 24, allowing the piston 26 to move more appropriately within the cylinder 24.

In addition, between the time when the piston 26 moves rearward from top dead center and the time when the front plate 32 abuts against the O-ring 38, and between the time when the piston 26 moves forward from bottom dead center and the time when the rear plate 34 abuts against the O-ring 38, the piston 26 (front plate 32 and rear plate 34) does not cause the O-ring 38 to slide against the inner surface of the cylinder 24. This reduces the movement resistance of the piston 26 when it is moved from top dead center and bottom dead center.

In this embodiment, the through hole 32A of the front plate 32 of the piston 26 opens radially outward from the front plate 32. However, the through hole 32A of the front plate 32 does not have to open radially outward from the front plate 32.

Furthermore, in this embodiment, the communication hole 34A of the rear plate 34 of the piston 26 opens radially outward from the rear plate 34. However, the communication hole 34A of the rear plate 34 does not have to open radially outward from the rear plate 34.

Furthermore, in this embodiment, a communication hole 34A is provided in the rear plate 34. However, the communication hole 34A does not have to be provided in the rear plate 34. In this case, the outer diameter of the rear plate 34 may be smaller than in this embodiment, as long as it is larger than the inner diameter of the O-ring 38.

In addition, in this embodiment, the cross section (cross section perpendicular to the circumferential direction) of the O-ring 38 is circular. However, the cross section (cross section perpendicular to the circumferential direction) of the O-ring 38 may be elliptical, or part or all of the cross section (cross section perpendicular to the circumferential direction) of the O-ring 38 may be polygonal.

Furthermore, in this embodiment, the inner circumferential shape of the cylinder 24 is circular. However, the inner circumferential shape of the cylinder 24 may also be elliptical or rectangular.

In addition, in this embodiment, the outer circumferential shape of the piston 26 is circular. However, the outer circumferential shape of the piston 26 may also be elliptical or rectangular.

Furthermore, in this embodiment, the front plate 32 and rear plate 34 of the piston 26 are integrated. However, the front plate 32 and rear plate 34 of the piston 26 may also be separate pieces.

10: Air pump, 14: Motor (movement device), 24: Cylinder, 24B: Discharge hole, 26: Piston, 32: Front plate (one side), 32A: Passage hole, 24: Rear plate (other side), 34A: Communication hole, 36A: Protrusion, 38: O-ring (sealing member), 40: Communication passage

Claims (7)

a cylinder having a discharge hole on one side;
a piston that is movable within the cylinder, has one side and another side, and has a passage hole formed in the one side;
a seal member disposed between the one side portion and the other side portion;
a moving device in which, when the piston is moved to one side, the seal member seals between the cylinder and the other side portion, thereby sealing the gap between the cylinder and the piston, and thereby air is discharged from the discharge hole, and, when the piston is moved to the other side, the seal member does not seal the passage hole, so that the gap between the cylinder and the piston is not sealed;
a plurality of communication holes provided on the other side portion, the number of which is greater than the number of the passage holes, the communication holes being sealed by the seal member when the moving device moves the piston to one side;
An air pump comprising: a cylinder having a discharge hole on one side;
a piston that is movable within the cylinder, has one side and another side, and has a passage hole formed in the one side;
a seal member disposed between the one side portion and the other side portion;
a moving device in which, when the piston is moved to one side, the seal member seals between the cylinder and the other side portion, thereby sealing the gap between the cylinder and the piston, and thereby air is discharged from the discharge hole, and, when the piston is moved to the other side, the seal member does not seal the passage hole, so that the gap between the cylinder and the piston is not sealed;
a communication hole that is provided in the other side portion, the communication hole being positioned in the circumferential direction of the piston and the passage hole being positioned in the circumferential direction of the piston, and that is sealed by the seal member when the moving device moves the piston to one side;
An air pump comprising: a cylinder having a discharge hole on one side;
a piston that is movable within the cylinder, has one side and another side, and has a passage hole formed in the one side;
a seal member disposed between the one side portion and the other side portion;
a moving device in which, when the piston is moved to one side, the seal member seals between the cylinder and the other side portion, thereby sealing the gap between the cylinder and the piston, and thereby air is discharged from the discharge hole, and, when the piston is moved to the other side, the seal member does not seal the passage hole, so that the gap between the cylinder and the piston is not sealed;
a protrusion provided on the piston, protruding toward the seal member, and curved concavely, the protrusion forming a communication passage between the seal member and one side of the piston when the moving device moves the piston to the other side;
An air pump comprising: a cylinder having a discharge hole on one side;
a piston that is movable within the cylinder, has one side and another side, and has a passage hole formed in the one side;
a seal member disposed between the one side portion and the other side portion;
a moving device in which, when the piston is moved to one side, the seal member seals between the cylinder and the other side portion, thereby sealing the gap between the cylinder and the piston, and thereby air is discharged from the discharge hole, and, when the piston is moved to the other side, the seal member does not seal the passage hole, so that the gap between the cylinder and the piston is not sealed;
a protrusion provided on the piston, protruding toward the seal member, and arranged on one side of the outer periphery of the piston along the moving direction of the piston , linearly continuing with the circumferential surface of the passage hole, forming a communication passage between the one side of the piston and the seal member, which communicates with the other side of the piston when the moving device moves the piston to the other side;
An air pump comprising: An air pump according to any one of claims 1 to 4, wherein the outer periphery of the one side portion is capable of contacting the cylinder. An air pump according to any one of claims 1 to 5, wherein the outer periphery of the other side portion is capable of contacting the cylinder. An air pump according to any one of claims 1 to 6, wherein the cross section of the sealing member is circular.