Diaphragm pump

Abstract

The invention provides a diaphragm pump in which a center plate is not liable to warp. A diaphragm pump (1) is provided with: a pump housing (10); a crank mechanism (20) attached to the pump housing (10); and a diaphragm structure (22) connected to the crank mechanism (20). The diaphragm structure section (22) has a diaphragm (30) and a center plate (32) that holds an inner peripheral section (38) of the diaphragm (30). The center plate (32) has: a first holding member (34) having a fitting recess (52); and a second holding member (36) having a fitting projection (58) press-fitted and fitted to the fitting recess (52), the second holding member (36) sandwiching an inner peripheral portion (38) of the diaphragm (30) between the first holding member (34) and the second holding member (36). A screw (48) for fixing the center plate (32) is mounted by passing through insertion holes (54, 60) of the fitting recess (52) and the fitting projection (58). The inner diameter of the fitting recess (52) and the outer diameter of the fitting projection (58) are larger than those of the insertion holes (54, 60).

Description

Technical Field

[0001] The present invention relates to a diaphragm pump that performs suction and discharge of a fluid by reciprocatingly vibrating a diaphragm. Background Art

[0002] For example, as shown in Patent Document 1, a diaphragm pump installs a center plate at the center of a disk-shaped diaphragm formed of an elastic member such as rubber, and reciprocates the center plate through a drive mechanism such as a crank mechanism and an electromagnetic reciprocating mechanism, thereby sucking and discharging fluids such as air or water. The center plate is composed of an inner center plate and an outer center plate, which are fixed to the drive mechanism by being pressed by screws in a manner that the diaphragm is clamped between them. It should be noted that a recess is formed in the center of the outer center plate, and a convex portion is formed in the center of the inner center plate, and by inserting the convex portion into the recess, the center positions of the outer center plate and the inner center plate are aligned.

[0003] Existing patent literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-225190 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the diaphragm pump as described above, the demand for high output and high flow rate is increasing. As a means for high output and high flow rate, increasing the diaphragm diameter can be cited. In this case, it is preferred that the center plate is also increased as the diaphragm diameter is increased. However, when the center plate is increased, the distance from the center position held by the screws to the outer peripheral end of the center plate becomes longer, and accordingly, when the center plate reciprocates, the center plate is prone to warping due to the force received from the diaphragm. As a result, a gap is generated between the inner center plate and the outer center plate, and the diaphragm cannot be maintained, and the diaphragm may be offset relative to the center plate.

[0008] Therefore, an object of the present invention is to provide a diaphragm pump in which warping is unlikely to occur in the center plate even if the center plate has a larger diameter.

[0009] Means for solving problems

[0010] That is, the present invention provides a diaphragm pump, wherein:

[0011] The diaphragm pump has:

[0012] Pump housing;

[0013] A driving mechanism portion, which is mounted on the pump housing;

[0014] a diaphragm having an outer peripheral portion and an inner peripheral portion, wherein the outer peripheral portion is fixed to the pump housing;

[0015] a center plate connected to the driving mechanism portion and holding the inner peripheral portion of the diaphragm, the center plate having a first holding member and a second holding member, the first holding member having a fitting recess, the second holding member having a fitting protrusion pressed into and fitted in the fitting recess, the inner peripheral portion of the diaphragm being clamped between the first holding member and the second holding member, the center plate having an insertion hole extending through the fitting recess and the fitting protrusion; and

[0016] a fixing member which is installed through the insertion hole and is used to fix the diaphragm to the driving mechanism part via the center plate,

[0017] An inner diameter of the fitting recess and an outer diameter of the fitting projection are larger than those of the insertion hole.

[0018] In this diaphragm pump, the first and second holding members of the center plate are fixed by fitting the fitting recess and the fitting protrusion which are larger than the insertion hole for fixing the fixing member, so that the distance from the fixing position to the outer peripheral end of the center plate can be shortened. Thus, even if the first and second holding members of the center plate are subjected to force from the diaphragm in the direction of separation from each other during driving, the first and second holding members are less likely to be warped. In particular, even when the diameter of the center plate is increased, the diameter of the fitting recess and the fitting protrusion is increased accordingly, so that warping during driving can be prevented.

[0019] In addition, only a portion of the outer circumferential surface of the fitting convex portion may be engaged with the inner circumferential surface of the fitting concave portion, and a retreat space may be formed between the inner circumferential surface of the fitting concave portion and the outer circumferential surface of the fitting convex portion. More specifically, the fitting convex portion may have a portion that is recessed radially inward, and the retreat space is formed by the recessed portion. More specifically, the fitting convex portion may have a plurality of recessed portions that are equally spaced in the circumferential direction, thereby forming a plurality of protrusions that protrude radially outward, and only the outer circumferential surfaces of the plurality of protrusions are engaged with the inner circumferential surface of the fitting concave portion.

[0020] By providing a retreat space between the inner circumferential surface of the fitting concave portion and the outer circumferential surface of the fitting convex portion, the deformation of the fitting concave portion and the fitting convex portion generated when the fitting concave portion is pressed into the fitting convex portion can be released into the retreat space. As a result, the fitting concave portion and the fitting convex portion can be firmly fitted and fixed, and excessive stress can be prevented from being generated in other parts of the first holding member and the second holding member, which can prevent them from being warped or otherwise deformed when the first holding member and the second holding member are assembled.

[0021] Hereinafter, embodiments of the diaphragm pump according to the present invention will be described with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a perspective view of a diaphragm pump according to one embodiment of the present invention.

[0023] Figure 2 yes Figure 1 A cross-sectional view of a diaphragm pump at the center of the diaphragm.

[0024] Figure 3 It is a cross-sectional view of the diaphragm structure.

[0025] Figure 4 is a perspective view of an upper surface of a first retaining member of a center plate.

[0026] Figure 5 is a perspective view of the lower surface of the second retaining member of the center plate.

[0027] Figure 6 yes Figure 3 Cross-sectional view at line A-A. DETAILED DESCRIPTION

[0028] like Figure 1 As shown, a diaphragm pump 1 according to an embodiment of the present invention includes a pump housing 10 and a motor 12 mounted on the pump housing 10, and the pump housing 10 is provided with a suction port 14 and a discharge port 16. The diaphragm pump 1 reciprocates a diaphragm structure 22, which is built into the pump housing 10 and will be described later, by the motor 12, thereby sucking air from the suction port 14 and discharging it from the discharge port 16. The diaphragm pump 1 is mounted at a predetermined position via a vibration-proof rubber 18.

[0029] like Figure 2 As shown, the diaphragm pump 1 further includes a crank mechanism 20 connected to the motor 12 and a diaphragm structure 22 mounted on the crank mechanism 20. A pump chamber 24 is formed between the inner peripheral surface 10a of the pump housing 10 and the diaphragm structure 22. A one-way valve 26 is installed between the suction port 14 and the pump chamber 24, which allows only air from the suction port 14 to pass through the pump chamber 24. In addition, a one-way valve 28 is installed between the pump chamber 24 and the discharge port 16, which allows only air from the pump chamber 24 to pass through the discharge port 16. The diaphragm structure 22 reciprocates mainly in the up-and-down direction by the crank mechanism 20, thereby increasing and decreasing the volume of the pump chamber 24, and air is sucked from the suction port 14 to the pump chamber 24 and sent from the pump chamber 24 to the discharge port 16.

[0030] The diaphragm structure 22 is composed of a disk-shaped diaphragm 30 and a center plate 32 that holds the diaphragm 30. Figure 3As shown in FIG. 1 , the center plate 32 is composed of a first holding member 34 at the lower side and a second holding member 36 at the upper side, which clamp and hold the inner peripheral portion 38 of the diaphragm 30. The diaphragm 30 has an outer peripheral stopper 42 protruding upward at its outer peripheral portion 40, an inner peripheral stopper 44 protruding downward at the inner peripheral portion 38, and an intermediate curved portion 46 curved upward at the intermediate position. Figure 2 As shown, the outer peripheral stopper portion 42 of the diaphragm 30 is fixed to the pump housing 10 . In addition, the center plate 32 is fixed to the connecting rod 50 of the crank mechanism 20 by means of screws (fixing members) 48 .

[0031] like Figure 4 As shown in FIG. 1 , the first holding member 34 of the center plate 32 has a circular fitting recess 52 and an insertion hole 54 extending through the center thereof on the upper surface 34a. An annular retaining groove 56 is also formed on the upper surface 34a of the first holding member 34 at the outer position of the fitting recess 52. Figure 5 As shown in FIG. 1 , the second holding member 36 of the center plate 32 has a fitting protrusion 58 and an insertion hole 60 extending through the center position thereof on the lower surface 36a. Two annular protrusions 62 are further formed on the lower surface 36a of the second holding member 36 at the outer position of the fitting protrusion 58. The fitting protrusion 58 has six radially inwardly recessed portions 64 at equal intervals in the circumferential direction, thereby forming six protruding protrusions 66. The fitting protrusion 58 has a gear-like shape.

[0032] like Figure 3 As shown, with the inner peripheral retaining portion 44 of the diaphragm 30 inserted into the annular retaining groove 56 of the first retaining member 34, the fitting protrusion 58 of the second retaining member 36 is pressed into and fitted into the fitting recess 52 of the first retaining member 34, thereby assembling the diaphragm structure 22. The inner peripheral portion 38 of the diaphragm 30 is clamped and held between the upper surface 34a of the first retaining member 34 and the lower surface 36a of the second retaining member 36. In addition, the two annular protrusions 62 of the second retaining member 36 are sunken into the diaphragm 30, thereby more firmly holding the diaphragm 30. As shown in FIG. Figure 6As shown, a retreat space 68 is formed between the fitting convex portion 58 and the fitting concave portion 52 at the recessed portion 64 of the fitting convex portion 58. In addition, the fitting convex portion 58 is engaged with the inner circumferential surface 52a of the fitting concave portion 52 only at the outer circumferential surface 58a on the protruding portion 66 thereof. In the state before assembly, the outer diameter of the fitting convex portion 58 is substantially the same as or slightly larger than the inner diameter of the fitting concave portion 52. Therefore, if the fitting convex portion 58 is pressed into the fitting concave portion 52, the protruding portion 66 of the fitting convex portion 58 or the fitting concave portion 52 may be slightly deformed, but since the deformed portion can be evacuated to the adjacent retreat space 68, unnecessary stress will not act on other portions. In the absence of the retreat space 68, the retreat place of the deformed portion disappears, and sometimes a large stress acts on other portions, especially near the root of the fitting convex portion 58, causing the second retaining member 36 to warp as a whole. In contrast, in this embodiment, a retreat space 68 is provided, so that the warping during assembly can be prevented. It should be noted that the shape and number of the protrusion 66 and the retreat space 68 can be changed arbitrarily. In addition, the inner circumferential surface 52a of the fitting recess 52 can also be formed with a portion that is recessed radially outward to form a retreat space. Other various shapes can also be considered, as long as only a part of the outer circumferential surface 58a of the fitting protrusion 58 is engaged with the inner circumferential surface 52a of the fitting recess 52 when the fitting protrusion 58 is pressed into the fitting recess 52 and a retreat space is formed in other parts, then any shape can also be used.

[0033] The assembled diaphragm structure 22 is fixed to the connecting rod 50 of the crank mechanism 20 by the screw 48 as described above, but the first holding member 34 and the second holding member 36 of the center plate 32 are substantially fixed to each other by the fitting concave portion 52 and the fitting convex portion 58 fitting together.

[0034] In the diaphragm pump 1, the first holding member 34 and the second holding member 36 of the center plate 32 holding the diaphragm 30 are fixed to each other integrally not by the screw 48 but mainly by the fitting of the fitting recess 52 and the fitting protrusion 58. Since the inner diameter of the fitting recess 52 and the outer diameter of the fitting protrusion 58 are larger than the insertion holes 54 and 60, the distance from the inner peripheral surface 52a of the fitting recess 52 and the outer peripheral surface 58a of the fitting protrusion 58 that fit together to the outer peripheral end 32a of the center plate 32 is shorter than the distance from the screw 48 to the outer peripheral end 32a of the center plate 32. During the driving process, the outer peripheral portion 70 of the second holding member 36 of the center plate 32 receives a force from the diaphragm 30 in a direction away from the first holding member 34, but the distance from the outer peripheral surface 58a of the fitting protrusion 58 where the second holding member 36 is fixed relative to the first holding member 34 to the outer peripheral end 32a thereof is shortened, and thus the second holding member 36 is less likely to be warped compared to the case where the fitting protrusions 58 are fixed to each other only by the screws 48. In addition, the fitting recess 52 is fitted with the fitting protrusion 58, so that the first holding member 34 and the second holding member 36 can be prevented from rotating relative to each other. Thus, it is possible to prevent the second holding member 36 from rotating when the screw 48 is tightened and an unnecessary force from being applied to the diaphragm 30, or to prevent the second holding member 36 from rotating during the driving process and causing the screw 48 to loosen.

[0035] The embodiments of the present invention are described above, but the present invention is not limited to these embodiments. For example, the first retaining member of the center plate may be formed as an integral component with the connecting rod of the crank mechanism. In addition, it may be configured so that the second retaining member of the center plate is fixed to the crank mechanism and the first retaining member is fixed to the second retaining member. That is, it is also possible to form an interlocking protrusion on the member on the connecting rod side and to form an interlocking recess on the other member. In the above-mentioned embodiment, a structure composed of a motor and a crank mechanism is used as the driving mechanism part, but other mechanisms such as an electromagnetic reciprocating motion mechanism may also be used. In addition, the fluid used as the conveying object is not limited to air, and liquids such as water may also be conveyed.

[0036] Description of reference numerals:

[0037] 1Diaphragm pump

[0038] 10 Pump housing

[0039] 10a Inner circumference

[0040] 12 Motor

[0041] 14 suction port

[0042] 16 outlets

[0043] 18 Anti-vibration rubber

[0044] 20 Crank mechanism

[0045] 22 Diaphragm structure

[0046] 24 Pump Room

[0047] 26 Check valve

[0048] 28 Check valve

[0049] 30 Diaphragm

[0050] 32 center plate

[0051] 32a Outer peripheral end

[0052] 34 first retaining member

[0053] 34a Upper surface

[0054] 36 second holding member

[0055] 36a Lower surface

[0056] 38 Inner circumference

[0057] 40 peripheral part

[0058] 42 peripheral stopper

[0059] 44 inner circumference stopper

[0060] 46 Middle bend

[0061] 48 screws (fixing components)

[0062] 50 Connecting rod

[0063] 52 fitting recess

[0064] 52a Inner Surface

[0065] 54 through hole

[0066] 56 annular retaining groove

[0067] 58 fitting convex part

[0068] 58a Outer surface

[0069] 60 through hole

[0070] 62 annular protrusion

[0071] 64 Concave part

[0072] 66 protrusion

[0073] 68 Retreat Space

[0074] 70 peripheral part.

Claims

1. A diaphragm pump, wherein: The diaphragm pump has: Pump housing; A driving mechanism portion, which is mounted on the pump housing; a diaphragm having an outer peripheral portion and an inner peripheral portion, wherein the outer peripheral portion is fixed to the pump housing; a center plate connected to the driving mechanism portion and holding the inner peripheral portion of the diaphragm, the center plate having a first holding member and a second holding member, the first holding member having a fitting recess, the second holding member having a fitting protrusion pressed into and fitted in the fitting recess, the inner peripheral portion of the diaphragm being clamped between the first holding member and the second holding member, and having an insertion hole extending through the fitting recess and the fitting protrusion; and a fixing member which is installed through the insertion hole and is used to fix the diaphragm to the driving mechanism portion via the center plate, An inner diameter of the fitting recess and an outer diameter of the fitting projection are larger than those of the insertion hole.

2. The diaphragm pump according to claim 1, wherein: Only a portion of the outer peripheral surface of the fitting convex portion is engaged with the inner peripheral surface of the fitting concave portion, and a retreat space is formed between the inner peripheral surface of the fitting concave portion and the outer peripheral surface of the fitting convex portion.

3. The diaphragm pump according to claim 2, wherein: The fitting protrusion has a portion that is recessed radially inward, and the recessed portion forms the escape space.

4. The diaphragm pump according to claim 3, wherein: The fitting convex portion has a plurality of the concave portions at equal intervals in the circumferential direction, thereby forming a plurality of protrusions protruding radially outward, and only the outer circumferential surfaces of the plurality of protrusions engage with the inner circumferential surface of the fitting concave portion.

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