Diaphragm pump

Abstract

The present invention provides a diaphragm pump that can increase the flow path cross-sectional area of ​​the suction and discharge through-holes while preventing damage to the valve body. [Solution] The system comprises a diaphragm having a pump section, a pump chamber, an intake passage, a discharge passage, a drive mechanism that converts the rotation of a motor into reciprocating motion to deform the pump section, an intake valve 31, and a discharge valve 41. The discharge passage includes a discharge through-hole 33 that penetrates the valve holder 8. The discharge valve 41 has a valve body 44 that closes the discharge through-hole 33. The valve body 44 has a sealing surface 48 that is in close contact with the outer wall surface 8a of the valve holder 8. A recess 49 is formed in the portion of the sealing surface 48 that corresponds to the discharge through-hole 33.

Description

Technical Field

[0001] The present invention relates to a diaphragm pump provided with a valve that adheres to the opening edge of a through-hole serving as a fluid passage.

Background Art

[0002] Conventionally, as a diaphragm pump provided with a valve that opens and closes a through-hole serving as a fluid passage, for example, there is one described in Patent Document 1. The diaphragm pump shown in Patent Document 1 includes a flat partition wall that forms part of the wall of the pump chamber. In this partition wall, a suction through-hole that forms part of the suction passage and a discharge through-hole that forms part of the discharge passage are drilled.

[0003] The suction valve of this diaphragm pump is configured such that a valve body provided in the pump chamber opens and closes the opening of the suction through-hole. The valve body of this suction valve has a sealing surface that adheres to the inner wall surface on the pump chamber side of the partition wall. Further, the discharge valve of this diaphragm pump is configured such that a valve body provided outside the pump chamber opens and closes the opening of the discharge through-hole. The valve body of this discharge valve has a sealing surface that adheres to the outer wall surface on the side opposite to the pump chamber of the partition wall. In recent years, diaphragm pumps including the diaphragm pump described in Patent Document 1 have been required to further improve the suction efficiency and discharge efficiency. In order to increase the suction efficiency and discharge efficiency, it is effective to increase the flow path cross-sectional area of the flow path composed of the suction through-hole and the discharge through-hole, and to form the opening of the through-hole into a shape with a small inlet loss.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, conventional diaphragm pumps have limitations in increasing the cross-sectional area of ​​the suction and discharge through-holes, making it difficult to further improve suction and discharge efficiency. The reason why the cross-sectional area of ​​the flow path cannot be further increased is that the suction and discharge valves become more susceptible to wear. Pressure may be applied to the valve bodies of the intake and discharge valves toward the intake and discharge through-holes. In the case of the intake valve, the valve body is pushed toward the through-hole when the pump chamber is in the discharge stroke. In the case of the discharge valve, the valve body is pulled toward the through-hole when the pump chamber is in the intake stroke. Furthermore, in the case of a multi-cylinder diaphragm pump with multiple pump chambers, the discharge pressure from other cylinders may be applied to the valve body of the discharge valve, causing this valve body to be pushed toward the through-hole.

[0006] If the diameter of the through-hole is increased, a portion of the valve body's sealing surface will bite into the through-hole when the valve body is pushed toward it. In other words, over a long period of time, the valve body will be damaged by repeated biting into the opening edge of the through-hole, causing the suction valve and discharge valve to become the bottleneck in the diaphragm pump's lifespan. As a result, it is not possible to increase the flow path cross-sectional area by increasing the diameter of the suction and discharge through-holes.

[0007] The objective of the present invention is to provide a diaphragm pump that can increase the flow path cross-sectional area of ​​the suction through-hole and discharge through-hole while preventing damage to the valve body. [Means for solving the problem]

[0008] To achieve this objective, the diaphragm pump according to the present invention comprises a diaphragm having a cup-shaped pump section, a pump chamber formed by a partition wall closing the opening portion of the pump section and the pump section, an intake passage communicating with the pump chamber, a discharge passage communicating with the pump chamber, a drive mechanism that converts the rotation of a motor into reciprocating motion to alternately deform the pump section in a direction that increases the volume of the pump chamber and in a direction that decreases the volume of the pump chamber, and a rubber material which elastically deforms during the stroke in which the volume of the pump chamber increases to open the intake passage, and in the other strokes to open the intake passage. The pump comprises an intake valve that closes a passage and a discharge valve made of rubber material that elastically deforms during a stroke in which the volume of the pump chamber decreases to open the discharge passage and closes the discharge passage during other strokes, wherein at least one of the intake passage and the discharge passage includes a through hole that penetrates the partition wall, and the valve of the intake valve and the discharge valve that opens and closes the passage having the through hole has a valve body that closes the through hole by making close contact with the wall surface of the partition wall through which the through hole opens, the valve body has a sealing surface that makes close contact with the wall surface, and a recess is formed in the portion of the sealing surface corresponding to the through hole.

[0009] In the present invention, the opening width of the recess may be larger than the opening width of the through hole in the diaphragm pump.

[0010] The present invention relates to a diaphragm pump in which the pump chamber and the through-hole are provided at multiple positions arranged at equal intervals in the circumferential direction of a virtual circle located on the same axis as the motor axis, the through-hole is a discharge through-hole included in the discharge passage, the valve having the valve body is a discharge valve, the discharge valve is provided on the same axis as the motor axis and has the valve body at positions corresponding to the multiple pump chambers, the recess is provided for each discharge through-hole, and the opening shape of the recess may be formed to extend in the circumferential direction of the virtual circle.

[0011] In the present invention, the diaphragm pump may be formed such that the opening on the downstream side of the through hole gradually increases in diameter from the inside of the partition wall toward the wall surface.

[0012] In the present invention, in the diaphragm pump, the opening of the through hole that opens to the wall surface in which the valve body of the partition wall is in close contact may be formed in a shape in which the diameter of the through hole gradually increases from the inside of the partition wall toward the wall surface. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a diaphragm pump that can increase the flow path cross-sectional area of ​​the suction through-hole and discharge through-hole while preventing damage to the valve body. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a cross-sectional view of the diaphragm pump according to the present invention. [Figure 2] Figure 2 shows the discharge valve. [Figure 3] Figure 3 is a cross-sectional view showing an enlarged view of the main part. [Modes for carrying out the invention]

[0015] Hereinafter, one embodiment of the diaphragm pump according to the present invention will be described in detail with reference to Figures 1 to 3. The diaphragm pump 1 shown in Figure 1 is attached to the motor 2 located at the bottom of Figure 1 and is driven and operated by this motor 2. The diaphragm pump 1 in this embodiment is a pump that inhales and discharges air. This diaphragm pump 1 includes a housing 3 fixed to a motor 2. The functional components that make up this diaphragm pump 1 are held in this housing 3.

[0016] The housing 3 is formed in a cylindrical shape by combining a plurality of members in the axial direction of the motor 2 and is positioned on the same axis as the rotation axis 4 of the motor 2. The plurality of members constituting the housing 3 include a bottom body 5 in the shape of a bottomed cylinder attached to the motor 2, a diaphragm holder 6 attached to the opening portion of the bottom body 5, a disc-shaped valve holder 8 attached to the diaphragm holder 6 with a diaphragm 7, which will be described later, sandwiched therebetween, a lid body 9 attached in a state of overlapping the valve holder 8, and the like. In this embodiment, the valve holder 8 corresponds to the "partition wall" in the present invention. The valve holder 8 is formed in a disc shape located on the same axis as the axis C1 of the motor 2.

[0017] The diaphragm 7 is held sandwiched between the diaphragm holder 6 and the valve holder 8. Further, the diaphragm 7 has a plurality of cup-shaped pump portions 11 that open toward the valve holder 8. These pump portions 11 are respectively provided at positions that divide the diaphragm 7 into a plurality in the circumferential direction of the housing 3. The diaphragm pump 1 according to this embodiment is a three-cylinder type having three pump portions 11. FIG. 1 is drawn so that two of the three cylinders are shown. The opening portion of the pump portion 11 is blocked by the valve holder 8.

[0018] A pump chamber 12 is formed between the pump portion 11 and the valve holder 8. For this reason, the diaphragm 7 constitutes a part of the wall of the pump chamber 12. The pump chambers 12 are respectively provided at a plurality of positions (three positions) arranged at equal intervals in the circumferential direction of the housing 3. A connecting piece 13 that protrudes in a direction opposite to the pump chamber 12 is provided on the bottom wall 11a of the cup-shaped pump portion 11. A drive mechanism 21 is connected to the connecting piece 13.

[0019] The drive mechanism 21 includes a crank body 22 attached to the rotating shaft 4 of the motor 2, and a drive body 24 connected to the crank body 22 via a drive shaft 23. The crank body 22 is fixed to the rotating shaft 4 and rotates integrally with the rotating shaft 4. The crank body 22 and the drive body 24 are formed of a plastic material. The drive shaft 23 is formed of a metal material.

[0020] The drive shaft 23 is fixed to the eccentric portion of the crank body 22 in a state inclined with respect to the rotating shaft 4 of the motor 2. The direction in which the drive shaft 23 inclines is the direction in which the amount of eccentricity with respect to the rotating shaft 4 decreases at the tip of the drive shaft 23.

[0021] The drive body 24 is composed of a columnar shaft portion 25 to which the drive shaft 23 is connected, and a plurality of arm portions 26 protruding radially outward from the shaft portion 25. The shaft portion 25 is composed of a bearing member 25a that rotatably supports the drive shaft 23, and a cylindrical body 25b that covers the bearing member 25a.

[0022] The arm portions 26 of the drive body 24 are provided for each pump portion 11 of the diaphragm 7 and extend radially outward from the shaft portion 25. Through holes 26a are formed in the arm portions 26. The connecting pieces 13 of the diaphragm 7 are engaged with the through holes 26a. The connecting pieces 13 are fixed to the arm portions 26 in a state of passing through the arm portions 26. Therefore, the arm portions 26 are respectively connected to the plurality of pump portions 11 of the diaphragm 7.

[0023] According to this drive mechanism 21, when the rotating shaft 4 of the motor 2 rotates, the crank body 22 and the drive shaft 23 rotate about the rotating shaft 4. At this time, since the rotation of the drive body 24 is restricted by the diaphragm 7, the drive body 24 swings as the direction of inclination of the drive shaft 23 changes. Due to this swinging, the arm portions 26 push and pull the pump portions 11. Therefore, the drive body 24 converts the rotation of the rotating shaft 4 into a reciprocating motion and transmits it to the pump portions 11.

[0024] As the pump section 11 of the diaphragm 7 is pulled toward the motor 2 by the arm section 26 and expands, the volume of the pump chamber 12 increases. On the other hand, as the pump section 11 of the diaphragm 7 is pushed toward the valve holder 8 by the arm section 26, the pump section 11 contracts and the volume of the pump chamber 12 decreases. Therefore, as the crank body 22 rotates continuously, the pump section 11 alternately deforms in a direction that increases the volume of the pump chamber 12 and in a direction that decreases the volume of the pump chamber 12, and the state of increasing volume and the state of decreasing volume of the pump chamber 12 alternately repeat.

[0025] The portion of the valve holder 8 that constitutes the wall of the pump chamber 12 is provided with an intake valve 31, and an intake through-hole 32 and a discharge through-hole 33 are formed therein. The intake valve 31 is made of rubber material and is provided for each pump chamber 12. The intake valve 31 in this embodiment has a shaft 31a that penetrates the valve holder 8 and is fixed to the valve holder 8, and a valve body 31b that is in close contact with the wall surface of the valve holder 8 on the pump chamber 12 side.

[0026] The suction through-hole 32 is a hole that penetrates the valve holder 8 and connects the pump chamber 12 to the suction fluid chamber 34, which will be described later. This suction through-hole 32 is included in the suction passage 35 that communicates with the pump chamber 12. The opening of the suction through-hole 32 on the pump chamber 12 side is opened and closed by the valve body 31b of the suction valve 31. The suction passage 35 opens when the valve body 31b moves away from this opening, and closes when the valve body 31b closes this opening. In other words, as shown on the right side of Figure 1, the suction valve 31 elastically deforms to open the suction passage 35 in the stroke in which the volume of the pump chamber 12 increases, and closes the suction passage 35 in other strokes.

[0027] The suction fluid chamber 34 is formed on the outer circumference between the valve holder 8 and the cover 9, and is separated from the discharge passage 36 (described later) by a cylindrical wall 9a protruding from the center of the valve holder 8. The tip of the cylindrical wall 9a is in airtight contact with the cover 9. In this embodiment, the upstream end of the suction fluid chamber 34 is formed by an intake pipe 37 provided on the outer circumference of the cover 9. The suction passage 35 is formed by the suction fluid chamber 34, which includes the internal space of this intake pipe 37, and the intake through-hole 32.

[0028] The discharge through-holes 33 are holes that constitute part of the discharge passage 36, which will be described later, and are formed to penetrate the wall portion of each pump chamber 12 in the valve holder 8. More specifically, the discharge through-holes 33 are provided at three locations, which are arranged at equal intervals in the circumferential direction of a virtual circle C2 {see Figure 2(A)} located on the same axis as the motor 2 axis C11.

[0029] The discharge passage 36 is composed of a discharge fluid chamber 38 formed in the central part between the valve holder 8 and the lid 9, inside the cylindrical wall 9a, the internal space of the discharge pipe 39 protruding from the axial center of the lid 9, and a discharge through-hole 33. The discharge through-hole 33 connects the pump chamber 12 and the discharge fluid chamber 38. In this embodiment, the discharge passage corresponds to "at least one of the suction passage and the discharge passage" as referred to in the present invention. A discharge valve 41 is provided within the discharge fluid chamber 38, at the center of the valve holder 8. This discharge valve 41 is a so-called hat-shaped valve and is made of rubber material.

[0030] As shown in Figures 2(A) to (C), the discharge valve 41 is formed in a disc shape overall. Figure 2(A) is a plan view of the discharge valve as seen from the cover side, Figure 2(B) is a bottom view of the discharge valve, and Figure 2(C) is a perspective cross-sectional view of the discharge valve. The break in Figure 2(C) is shown by the line II-II in Figure 2(B). The discharge valve 41 according to this embodiment is formed by a fixing projection 43 that is sandwiched between the valve holder 8 and the annular projection 42 (see Figure 1) of the cover 9 and fixed to these members, and a valve body 44 that is integrally formed with the fixing projection 43.

[0031] As shown in Figures 2(A) and (B), the fixing projection 43 is formed to extend radially in three directions from the center of the discharge valve 41. Furthermore, the fixing projection 43 is formed so as not to overlap with the discharge through-hole 33 when the discharge valve 41 is attached to the valve holder 8. The position of the discharge through-hole 33 relative to the discharge valve 41 attached to the valve holder 8 is indicated by the dashed line in Figures 2(A) and (B).

[0032] A recess 45 is formed in the portion of the fixing projection 43 that faces the valve holder 8. The recess 45 is shaped to accommodate a projection 46 (see Figure 1) that protrudes from the valve holder 8. The recess 45 and projection 46 are each formed in a roughly Y-shape, following the shape of the fixing projection 43 in a plan view, so that the circumferential position of the discharge valve 41 relative to the valve holder 8 does not change. By fitting the projection 46 into the recess 45, the discharge valve 41 is positioned on the same axis as the valve holder 8 and is provided on the same axis as the axis C1 of the motor 2.

[0033] The valve bodies 44 open and close the opening on the downstream side (discharge fluid chamber 38 side) of the discharge through hole 33, and are formed at three locations adjacent to the fixing projections 43 (positions corresponding to the pump chamber 12) in the plan view shown in Figure 2(A). Each valve body 44 is formed in a fan shape in a plan view, and is formed in a cantilever shape with the part connected to the fixing projection 43 as the base end and the arc of the fan as the free end. On the base end of each valve body 44 opposite to the valve holder 8 and connected to the fixing projection 43, a groove 47 is formed that extends along the fixing projection 43. The valve body 44 in which this groove 47 is formed has a weak part 44a (see Figure 3) at the base of the cantilever beam where the rigidity is partially reduced.

[0034] A flat sealing surface 48 is formed on the portion of the valve body 44 facing the valve holder 8, which is in close contact with the outer wall surface 8a (see Figure 3) of the valve holder 8 opposite to the pump chamber 12. This sealing surface 48 is located on the same plane as the portion of the fixing projection 43 facing the valve holder 8. The sealing surface 48 in close contact with the outer wall surface 8a causes the valve body 44 to close the discharge through-hole 33. A recess 49 is formed in the sealing surface 48 in the portion corresponding to the discharge through-hole 33. A recess 49 is provided for each discharge through-hole 33, in other words, for each of the three valve bodies 44.

[0035] The opening width of the recess 49 is greater than the opening width of the discharge through-hole 33. In this embodiment, the opening shape of the recess 49 is formed in an oval shape extending in the circumferential direction of the discharge valve 41, as shown in Figure 2(B). In other words, the opening shape of the recess 49 is formed in a shape that extends in the circumferential direction of a virtual circle C2 located on the same axis as the axis C1 of the motor 2. This recess 49 is formed in the area outside the groove 47 of the fan-shaped valve body 44 in a plan view, excluding the arc portion 44b of the fan. Furthermore, as shown in Figure 3, the recess 49 has a bottom surface 49a such that its depth is constant. A concave curved surface 49b is formed in the portion of the recess 49 from the opening edge to the bottom surface 49a.

[0036] As shown in Figure 3, the downstream opening of the discharge through-hole 33 (the upper opening in Figure 3) is formed in such a shape that the diameter of the discharge through-hole 33 gradually increases as it moves from the inside of the valve holder 8 toward the outer wall surface 8a. In this embodiment, the boundary between the discharge through-hole 33 and the outer wall surface 8a is formed by a convex curved surface 51.

[0037] In the diaphragm pump 1 configured in this way, the rotation of the motor 2 is converted into reciprocating motion by the drive mechanism 21 and sequentially transmitted to the three pump sections 11. When the pump section 11 moves in a direction that increases the volume of the pump chamber 12, the intake valve 31 opens the intake passage 35, and air is drawn into the pump chamber 12 through the intake passage 35. When the pump section 11 moves in a direction that decreases the volume of the pump chamber 12, the discharge valve 41 elastically deforms and opens the discharge passage 36, and air is discharged from the pump chamber 12 through the discharge passage 36.

[0038] Air is discharged from all pump chambers 12 into the discharge passage 36. Therefore, when the discharge valve 41 is closed, the valve body 44 may be pushed toward the discharge through-hole 33 by the pressure of the air discharged from the other pump chambers 12. In addition, the valve body 44 is pulled toward the discharge through-hole 33 by the negative pressure propagated from the discharge through-hole 33 during the suction stroke. When the valve body 44 is biased toward the discharge through-hole 33 in this way, the portion of the valve body 44 where the recess 49 is formed will bend toward the valve holder 8, as shown by the dashed line in Figure 3. That is, the distance between the valve body 44 and the opening of the discharge through-hole 33 is longer than when the recess 49 is not formed, so when the valve body 44 is biased toward the discharge through-hole 33, the valve body will not sink into the discharge through-hole 33 as in the conventional design. Therefore, according to this embodiment, it is possible to provide a diaphragm pump that can increase the flow path cross-sectional area of ​​the discharge through-hole while preventing damage to the valve body.

[0039] In this embodiment, the opening width of the recess 49 is larger than the opening width of the discharge through-hole 33. Therefore, compared to the case where the recess 49 is not formed, the pressure-receiving surface of the valve body 44 that receives the discharge pressure is larger. This means that the discharge valve 41 opens more easily. Therefore, in this embodiment, the resistance when the discharge valve 41 opens is reduced, making it possible to improve the discharge efficiency.

[0040] In this embodiment, the pump chamber 12 and discharge through-hole 33 are provided at multiple positions arranged at equal intervals in the circumferential direction of a virtual circle C2 located on the same axis as the motor 2's axis C1. The discharge valve 41 is located on the same axis as the motor 2's axis C1 and has a valve body 44 for each pump chamber 12. A recess 49 is provided for each discharge through-hole 33. The opening shape of the recess 49 is formed to extend in the circumferential direction of the virtual circle C2 described above. Therefore, even though multiple valve bodies 44 are provided in the discharge valve 41, a recess 49 with a large opening can be formed. As a result, the discharge efficiency can be further increased.

[0041] In this embodiment, the downstream opening of the discharge through-hole 33 is formed in such a shape that the diameter of the discharge through-hole 33 gradually increases from the inside of the valve holder 8 toward the outer wall surface 8a. Therefore, even if the valve body 44 is biased toward the discharge through-hole 33 and comes into contact with the discharge through-hole 33, the valve body 44 will not be damaged because there are no corners at the contact point. Thus, a highly reliable diaphragm pump can be realized in preventing damage to the valve body 44.

[0042] In the embodiments described above, an example of applying the present invention to the discharge valve 41 of a diaphragm pump 1 that uses air as the fluid was explained. However, the present invention can be applied to diaphragm pumps that use liquid as the fluid, and it can also be applied to suction valves. [Explanation of symbols]

[0043] 1...Diaphragm pump, 2...Motor, 7...Diaphragm, 8...Valve holder (bulkhead), 11...Pump section, 12...Pump chamber, 21...Drive mechanism, 31...Intake valve, 33...Discharge through-hole (through-hole), 35...Intake passage, 36...Discharge passage, 41...Discharge valve, 44...Valve body, 48...Sealing surface, 49...Recess, C1...Axis, C2...Imaginary circle.

Claims

1. A diaphragm having a cup-shaped pump section, A pump chamber formed by a partition wall that closes the opening portion of the pump section and the pump section, A suction passage connected to the aforementioned pump chamber, A discharge passage connected to the aforementioned pump room, A drive mechanism that converts the rotation of the motor into reciprocating motion to alternately deform the pump section in a direction that increases the volume of the pump chamber and in a direction that decreases the volume of the pump chamber, An intake valve, formed of a rubber material, elastically deforms during a stroke in which the volume of the pump chamber increases to open the intake passage, and closes the intake passage during other strokes, The pump comprises a discharge valve made of rubber material, which elastically deforms during a stroke in which the volume of the pump chamber decreases to open the discharge passage, and closes the discharge passage during other strokes. At least one of the intake passage and the discharge passage includes a through-hole that penetrates the partition wall. The valves among the intake valve and discharge valve that open and close the passage having the through hole have a valve body that closes the through hole by being in close contact with the wall surface of the partition wall through which the through hole opens. The valve body has a sealing surface that is in close contact with the wall surface, A diaphragm pump characterized in that a recess is formed in the portion of the sealing surface corresponding to the through hole.

2. In the diaphragm pump described in claim 1, A diaphragm pump characterized in that the opening width of the recess is greater than the opening width of the through hole.

3. In the diaphragm pump described in claim 2, The pump chamber and the through-hole are provided at multiple positions that are equally spaced in the circumferential direction of a virtual circle located on the same axis as the motor's axis. The aforementioned through-hole is a discharge through-hole included in the discharge passage, The valve having the valve body is a discharge valve, The discharge valve is provided on the same axis as the motor axis and has the valve body at a position corresponding to each of the multiple pump chambers. The recess is provided for each of the discharge through holes, A diaphragm pump characterized in that the opening shape of the recess is formed to extend in the circumferential direction of the virtual circle.

4. In a diaphragm pump as described in any one of claims 1 to 3, A diaphragm pump characterized in that the downstream opening of the through-hole is formed in such a shape that the diameter of the through-hole gradually increases as it moves from the inside of the partition wall toward the wall surface.

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