Diaphragm pump

Abstract

To provide a diaphragm pump in which coaxial adjustment of a bearing portion supporting a driving body can be easily performed, and wear resistance of the bearing portion is high.SOLUTION: A diaphragm pump comprises a diaphragm comprising a deformation part serving as a portion of a pump chamber, a crank body, a driving shaft provided in the crank body, and a driving body 44 rotatably supported by the driving shaft via a bearing member 43. The driving body 44 comprises a shaft part 51 and an arm part 52. The bearing member 43 comprises a first bearing member 43A and a second bearing member 43B. A first shaft hole 61A of the first bearing member 43A is a through hole, and a second shaft hole 61B of the second bearing member 43B is a non-through hole. An oil sump part 68 opened over a whole area in a circumferential direction in a shaft hole 61 is formed in a boundary portion between the first bearing member 43A and the second bearing member 43B.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a diaphragm pump provided with an oil reservoir for storing lubricating oil in a bearing portion of a driving body that converts rotation into reciprocating motion.

Background Art

[0002] As a conventional diaphragm pump of this type, for example, there is one described in Patent Document 1. The diaphragm pump disclosed in Patent Document 1 includes a crank body that is driven by a motor to rotate, a drive shaft having one end fixed to the crank body and inclined, and a drive body having a shaft portion rotatably supported by the drive shaft. The drive body has an arm portion extending radially outward from an end portion of the shaft portion opposite to the crank body, and converts the rotation of the motor into reciprocating motion and transmits it to a deformation portion that forms a pump chamber of the diaphragm from the arm portion.

[0003] The shaft portion of the drive body has a recess that opens toward the crank body and a bearing member that is housed in the recess and through which the drive shaft passes. A shaft hole formed of a non-through hole into which the tip of the drive shaft is rotatably fitted is formed at the center of the bottom surface of the recess. The bearing member is formed in a columnar shape and is fixed in a fitted state to the recess of the shaft portion in a state where the drive shaft is rotatably fitted and passes through. An oil reservoir for storing lubricating oil is formed at the boundary portion between the bottom surface of the recess and the bearing member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The diaphragm pump described in Patent Document 1 had two problems in the bearing portion of the drive body. The first problem is that coaxial adjustment is required between the shaft hole formed in the drive body and the recess that houses the bearing member, and this adjustment requires a great deal of time. Coaxial adjustment of the drive body is the process of positioning the shaft hole and the bearing member on the same axis. Coaxial adjustment is important because positioning the shaft hole and the bearing member on the same axis reduces the load during rotation. This coaxial adjustment is performed by machining the mold, and is carried out not only in the mold that forms the drive body, but also in the mold that forms the bearing member.

[0006] Coaxial adjustment of a mold for forming a drive unit includes adjusting the diameter of the shaft hole, adjusting the diameter of the recess, and aligning the shaft hole and the recess. Coaxial adjustment of a mold for forming a bearing member includes adjusting the inner and outer diameters of the bearing member and aligning the inner and outer surfaces of the bearing member.

[0007] Coaxial adjustment of the drive unit is performed whenever a new mold is created, when a mold is modified or corrected, or when another drive unit (with different materials, number of cylinders, etc.) that uses the same bearing components is created. The bearing components are smaller than the drive unit. The mold used to mold these bearing components is designed to mold multiple bearing components simultaneously. Therefore, when producing the same number of drive units and bearing components, the mold used to mold the drive units must be updated before the mold used to mold the bearing components. As a result, coaxial adjustment is performed on the mold used to mold the drive units more frequently, and there is a need to simplify the adjustment work performed on the mold used to mold the drive units so that it can be easily carried out.

[0008] The second problem is that the wear resistance of the shaft hole formed in the drive body is low. The drive body described in Patent Document 1 is formed as shown in Figure 10. The drive body 1 shown in Figure 10 has a shaft hole 2 in the center and three arm portions 3 extending radially from the shaft hole 2. The shaft hole 2 is a hole into which the tip of a drive shaft (not shown) is rotatably fitted. Through holes 4 are drilled in the tips of the arm portions 3 through which connecting pieces (not shown) provided at each deformed part of the diaphragm are inserted.

[0009] The shaft hole 2 is formed in approximately the same position as the arm portion 3 in the axial direction of the drive shaft. Therefore, around the shaft hole 2, there is a thick-walled portion A, which is relatively thicker because it is connected to the arm portion 3, and a thin-walled portion B, which is relatively thinner because it is connected between the arm portions 3. Compared to the thick-walled portion B, the thick-walled portion A generates more sink marks during the molding of the drive body 1. As a result, sink marks occur unevenly around the shaft hole 2 during molding. If the sink marks around the shaft hole 2 are uneven, the roundness of the shaft hole 2 tends to decrease, and the clearance between the hole wall of the shaft hole 2 and the drive shaft may become excessively narrow, causing the oil film between the shaft hole 2 and the drive shaft to be interrupted in some areas. As a result, wear progresses in the areas where the oil film is interrupted, and the wear resistance of the shaft hole 2 decreases as described above.

[0010] The objective of the present invention is to provide a diaphragm pump that simplifies the adjustment work performed on the mold for forming the drive body and improves the wear resistance of the bearing portion. [Means for solving the problem]

[0011] To achieve this objective, the diaphragm pump according to the present invention comprises a diaphragm having a deformable portion that constitutes part of the wall of the pump chamber, a crank body fixed to the rotating shaft of a motor, a tilted drive shaft with one end fixed at an eccentric position of the crank body, a drive body rotatably supported on the drive shaft via a bearing member and converting the rotation of the crank body into reciprocating motion and transmitting it to the deformable portion, and a pump mechanism that alternately repeats a state in which fluid is discharged from the pump chamber and a state in which fluid is drawn into the pump chamber as a result of the reciprocating motion of the drive body, wherein the drive body comprises a shaft portion that houses and holds the bearing member in a fitted state, and a radially outward portion from the shaft portion The bearing member has an arm portion that protrudes and is connected to the deformed portion, and the bearing member is composed of a first bearing member and a second bearing member that are stacked on top of each other in an axial direction of the drive shaft, the first bearing member and the second bearing member are formed in a cylindrical shape having an axial hole into which the drive shaft is rotatably fitted, the axial hole of one of the first bearing member and the second bearing member that is closer to the crank body is formed as a through hole, and the axial hole of the other bearing member is formed as a non-through hole, and an oil reservoir portion is formed at the boundary between the first bearing member and the second bearing member that opens over the entire circumferential direction of the axial hole.

[0012] The present invention relates to a diaphragm pump in which the oil reservoir is formed by a circular recess formed on at least one of the end faces of the first bearing member facing the second bearing member and the end face of the second bearing member facing the first bearing member, and the shaft bore may have an oil passage formed so that lubricating oil in the circular recess flows from the circular recess in at least one direction in the axial direction.

[0013] The present invention relates to a diaphragm pump in which the arm portion of the drive body is integrally formed with the end of the shaft portion opposite to the crank body, and of the first bearing member and the second bearing member, the other bearing member located opposite to the crank body is formed in a shape that reaches the end of the shaft portion in the axial direction of the drive shaft, and the space between the end of the shaft portion and the second bearing member may be an annular gap when viewed from the axial direction of the drive shaft. [Effects of the Invention]

[0014] In this invention, it is no longer necessary to provide a shaft hole in the drive body into which the drive shaft rotatably fits. Therefore, the only adjustment work required on the mold used to form the drive body is to adjust the inner diameter of the portion into which the bearing member fits. Furthermore, since the first and second bearing members are formed separately from the arms of the drive body, they are not affected by sink marks that occur during the molding of the drive body. As a result, the roundness of the shaft holes formed in the first and second bearing members can be maintained at a high level. Therefore, according to the present invention, it is possible to provide a diaphragm pump in which the adjustment work performed on the mold for forming the drive body is simplified, and the wear resistance of the bearing portion is improved. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a cross-sectional view of the diaphragm pump according to the present invention. [Figure 2] Figure 2 is a perspective cross-sectional view of the drive unit with the bearing member incorporated. [Figure 3] Figure 3 is an exploded perspective view of a part of the drive mechanism. [Figure 4] Figure 4 is an exploded perspective view of a part of the drive mechanism. [Figure 5] Figure 5 shows the bottom view and cross-sectional view of the drive unit. [Figure 6] Figure 6 shows a plan view and a cross-sectional view of the first bearing member. [Figure 7] Figure 7 shows the bottom view and cross-sectional view of the second bearing member. [Figure 8] FIG. 8 is a plan view and a sectional view showing a modified example of the first bearing member. [Figure 9] FIG. 9 is a bottom view and a sectional view showing a modified example of the second bearing member. [Figure 10] FIG. 10 is a sectional view of a conventional driving body.

BEST MODE FOR CARRYING OUT THE INVENTION

[0016] Hereinafter, an embodiment of a diaphragm pump according to the present invention will be described in detail with reference to FIGS. 1 to 8. The diaphragm pump 11 shown in FIG. 1 is attached to a motor 12 located at the bottom in FIG. 1 and is driven by this motor 12 to operate. The diaphragm pump 11 according to this embodiment is a pump that sucks and discharges air. This diaphragm pump 11 includes a housing 13 fixed to the motor 12. The functional components constituting this diaphragm pump 11 are held in this housing 13.

[0017] (Description of the housing) The housing 13 is formed in a columnar shape by combining a plurality of members in the axial direction of the motor 12 and is positioned on the same axis as the rotation axis 14 of the motor 12. The plurality of members constituting the housing 13 include a bottom body 15 having a bottom and being cylindrical and attached to the motor 12, a diaphragm holder 16 attached to the opening portion of the bottom body 15, and a disc-shaped valve holder 18 attached to the diaphragm holder 16 with a diaphragm 17 described later sandwiched between the diaphragm holder 16 and the diaphragm holder 16, and a lid body 19 attached in a state of overlapping the valve holder 18.

[0018] The diaphragm 17 is held between the diaphragm holder 16 and the valve holder 18. The diaphragm 17 also has a plurality of cup-shaped deformable portions 21 that open toward the valve holder 18. These deformable portions 21 are provided at positions that divide the diaphragm 17 into multiple parts in the circumferential direction of the housing 13. In this embodiment, the deformable portions 21 are provided at positions that divide the housing 13 into three equal parts in the circumferential direction. The opening of the deformed portion 21 is closed by the valve holder 18.

[0019] A pump chamber 22 is formed between this deformed portion 21 and the valve holder 18. Therefore, the deformed portion 21 constitutes part of the wall of the pump chamber 22. The bottom wall 21a of the cup-shaped deformed portion 21 is provided with a connecting piece 23 that protrudes in the direction opposite to the pump chamber 22.

[0020] (Explanation of the pump mechanism) A suction valve 24 is provided in the portion of the valve holder 18 that constitutes the wall of the pump chamber 22, and an suction passage 25 and a discharge passage 26 are open to it. The suction valve 24 is made of rubber material and is provided for each pump chamber 22. The suction valve 24 in this embodiment has a shaft portion 24a that penetrates the valve holder 18 and is fixed to the valve holder 18, and a valve body 24b that is in close contact with the wall surface of the valve holder 18 on the pump chamber 22 side.

[0021] The intake passage 25 is formed by connecting multiple holes and spaces. In this embodiment, the upstream end of the intake passage 25 is made up of an intake pipe 27 provided on the outer circumference of the cover 19. The internal passage 27a of this intake pipe 27 is in communication with the space S inside the diaphragm holder 16 via a first through hole 28 in the valve holder 18. On the other hand, the downstream end of the intake passage 25 is made up of a second through hole 29 that penetrates the valve holder 18 with one end opening into the pump chamber 22.

[0022] This second through-hole 29 connects the suction fluid chamber 30, formed between the valve holder 18 and the cover 19, to the pump chamber 22. The suction fluid chamber 30 is connected to the aforementioned space S via a fluid passage (not shown). The suction fluid chamber 30, although not shown in detail, is formed in an annular shape and is located coaxially with the housing 13, and is connected to each pump chamber 22 via a second through-hole 29 for each pump chamber 22. The opening portion of the second through-hole 29 on the pump chamber 22 side is closed by the valve body 24b of the suction valve 24.

[0023] The discharge passage 26 is composed of a discharge fluid chamber 31 formed in the axial center of the housing 13 between the valve holder 18 and the cover 19, a third through hole 32 drilled in the valve holder 18 so as to communicate the discharge fluid chamber 31 with the pump chamber 22, and a discharge pipe 33 protruding from the axial center of the cover 19. The internal space 33a of this discharge pipe 33 is connected to the discharge fluid chamber 31. A discharge valve 34 is provided inside the discharge fluid chamber 31. This discharge valve 34 is made of rubber material and has a valve body 34a that is in close contact with the wall surface of the valve holder 18 on the discharge fluid chamber 31 side. This valve body 34a closes the opening of the third through hole 32.

[0024] The discharge valve 34 and the aforementioned suction valve 24 open and close in accordance with the increase or decrease in the volume of the pump chamber 22. The discharge valve 34 opens during the contraction stroke when the volume of the pump chamber 22 decreases, and remains closed otherwise. The suction valve 24 opens during the expansion stroke when the volume of the pump chamber 22 increases, and remains closed otherwise. The volume of the pump chamber 22 changes as the deformable portion 21 of the diaphragm 17 is pushed or pulled by the drive mechanism 35, which will be described later.

[0025] In this embodiment, the pump mechanism 36 according to the present invention is composed of an intake valve 24 and a discharge valve 34, an intake pipe 27, a first through hole 28, a space S, a fluid passage (not shown), an intake fluid chamber 30, a second through hole 29, a third through hole 32, a discharge fluid chamber 31, a discharge pipe 33, and the like.

[0026] (Explanation of the drive mechanism) The drive mechanism 35 includes a crank body 41 attached to the rotating shaft 14 of the motor 12, a tilted drive shaft 42 with one end fixed to an eccentric position on the crank body 41, and a drive unit 44 rotatably supported on the drive shaft 42 via a bearing member 43. The crank body 41 has a first shaft hole 45 which is a non-through hole and a second shaft hole 46 which is a through hole, and is also provided with a counterweight 47 for vibration suppression. The second shaft hole 46 and the counterweight 47 are positioned on either side of the first shaft hole 45.

[0027] The rotating shaft 14 is press-fitted into the first shaft hole 45. Therefore, the crank body 41 is fixed to the rotating shaft 14 and rotates integrally with the rotating shaft 14. The crank body 41 and the drive body 44 are made of plastic material. The drive shaft 42 is made of metal material. In this embodiment, since the drive body 44 does not come into contact with the drive shaft 42, it does not need to be made of a material capable of supporting sliding parts, and is made of a material with the minimum necessary wear resistance and rigidity. The bearing member 43 is made of a plastic material that can slidably support the rotating drive shaft 42 and is also oil-resistant.

[0028] The drive shaft 42 is supported by the crank body 41, with one end 42a on the crank body 41 side fixed to a portion of the crank body 41 that is eccentric with respect to the rotation axis 14, and its axis C1 is inclined in a predetermined direction with respect to the axis C2 of the rotation axis 14. The drive shaft 42 is fixed to the crank body 41 by press-fitting one end 42a of the drive shaft 42 into a second shaft hole 46 drilled in the crank body 41. The direction in which the drive shaft 42 is inclined is such that the amount of eccentricity with respect to the rotation axis 14 at the other end 42b of the drive shaft 42 is reduced.

[0029] As shown in Figures 2 to 4, the drive unit 44 has a shaft portion 51 that houses and holds the bearing member 43 (described later) in a fitted state, and three arm portions 52 that protrude radially outward from the shaft portion 51. These arm portions 52 are integrally formed at the end 51a of the shaft portion 51 opposite to the crank body 41, and extend radially in three directions from the shaft portion 51. Through holes 52a are formed at the tips of the arm portions 52 through which the connecting piece 23 provided in the deformed portion 21 of the diaphragm 17 described above is inserted.

[0030] The shaft portion 51 is formed in a cylindrical shape by a mold (not shown) used to mold the drive body 44, and has first to third functional portions 53 to 55 arranged in the axial direction, as shown in Figures 2 and 5(A) and (B). Figure 5(A) is a bottom view of the drive body, and Figure 5(B) is a cross-sectional view taken along line VV in Figure 5(A). The end portion 51b of the shaft portion 51 adjacent to the crank body 41 is provided with the first functional portion 53. The first functional part 53 has the function of housing ring-shaped retaining members 56 and 57. In this embodiment, the first functional part 53 is fitted with two retaining members 56 and 57 so as to overlap in the axial direction of the shaft part 51. The retaining members 56 and 57 are formed in a ring shape having a number of elastic claw pieces 56a and 57a (see Figures 3 and 4) that press the inner circumferential surface of the first functional part 53 radially outward. These retaining members 56 and 57 are fixed to the first functional part 53 by the frictional force generated when the elastic claw pieces 56a and 57a press against the inner circumferential surface of the first functional part 53.

[0031] The second functional part 54 is located in the axial center of the shaft 51, adjacent to the first functional part 53, and has the function of housing the bearing member 43, which will be described later, in a fitted state. The inner diameter of the second functional part 54 is smaller than the inner diameter of the first functional part 53. The aforementioned retaining members 56 and 57 are for preventing the bearing member 43 from coming out of the second functional part 54 and moving towards the first functional part 53.

[0032] The third functional part 55 is located at the end 51a of the shaft 51 opposite to the crank body 41 and has the function of connecting the shaft 51 to the arm 52 of the drive body 44. The inner diameter of the third functional part 55 is smaller than the inner diameter of the second functional part 54. For this reason, the third functional part 55 has a ring-shaped end face 58 perpendicular to the axis of the drive shaft 42 at the boundary with the second functional part 54.

[0033] (Bearing component description) As shown in Figure 2, the bearing member 43 is composed of a first bearing member 43A and a second bearing member 43B that are stacked on top of each other in the axial direction (up and down direction in Figure 2) of the drive shaft 42. In this embodiment, the first bearing member 43A is positioned closer to the crank body 41 than the second bearing member 43B. These first bearing member 43A and second bearing member 43B are formed of plastic material in a cylindrical shape, each having a shaft hole 61 into which the drive shaft 42 is rotatably fitted. Hereinafter, the portion of the shaft hole 61 formed in the first bearing member 43A will simply be referred to as the first shaft hole 61A, and the portion formed in the second bearing member 43B will simply be referred to as the second shaft hole 61B.

[0034] Of the first bearing member 43A and the second bearing member 43B, the shaft hole (first shaft hole 61A) of the first bearing member 43A, which is the bearing member closer to the crank body 41, is formed as a through hole, as shown in Figures 6(A) and (B). Figure 6(A) is a plan view of the first bearing member 43A, and Figure 6(B) is a cross-sectional view taken along line VI-VI in Figure 6(A). The shaft hole (second shaft hole 61B) of the other bearing member, the second bearing member 43B, is formed as a non-through hole, as shown in Figures 7(A) and (B). Figure 7(A) is a bottom view of the second bearing member 43B, and Figure 7(B) is a cross-sectional view taken along line VII-VII in Figure 7(A).

[0035] As shown in Figure 6(B), the first bearing member 43A is formed in a cylindrical shape with a constant outer diameter from one end to the other in the axial direction of the drive shaft 42. The outer diameter of the first bearing member 43A is the diameter at which the first bearing member 43A is press-fitted into the second functional part 54 of the shaft 51. The first shaft hole 61A is formed in the axial center of the first bearing member 43A. A detailed explanation of the first shaft hole 61A will be given later.

[0036] The second bearing member 43B is formed in a cylindrical shape, having a large-diameter portion 62 with the same outer diameter as the first bearing member 43A, and a small-diameter portion 63 with a smaller outer diameter than the large-diameter portion 62. The outer diameter of the large-diameter portion 62 is the diameter at which the large-diameter portion 62 is press-fitted into the second functional portion 54. The second shaft hole 61B is formed in the axial center of the second bearing member 43B. A detailed description of the second shaft hole 61B will be given later. The axial length of the first bearing member 43A and the axial length of the large-diameter portion 62 of the second bearing member 43B are such that, when the first and second bearing members 43A and 43B are superimposed in the axial direction, the axial length of the second functional portion 54 of the shaft portion 51 is equal.

[0037] Therefore, when the large-diameter portions 62 of the first bearing member 43A and the second bearing member 43B are press-fitted into the second functional portion 54 and the retaining members 56 and 57 are assembled to the first functional portion 53, the large-diameter portion 62 of the second bearing member 43B abuts against the end face 58 which forms the boundary between the second functional portion 54 and the third functional portion 55 of the shaft portion 51, and the first and second bearing members 43A and 43B are held between the retaining members 56 and 57 and the end face 58.

[0038] The small-diameter portion 63 of the second bearing member 43B is formed in a shape that reaches the end 51a of the shaft portion 51 (the end opposite to the crank body 41 and the third functional portion 55) in the axial direction of the drive shaft 42. In this embodiment, as shown in Figure 2, the small-diameter portion 63 penetrates the third functional portion 55 of the shaft portion 51 in the axial direction of the drive shaft 42. The outer diameter of the small-diameter portion 63 is such that it can be loosely inserted into the third functional portion 55 of the shaft portion 51. The space between the end portion 51a (third functional portion 55) of the shaft portion 51 and the small-diameter portion 63 of the second bearing member 43B is an annular gap d (see Figure 5(A)) when viewed from the axial direction of the drive shaft 42. Therefore, when the large-diameter portion 62 of the second bearing member 43B is press-fitted into the shaft portion 51 (second functional portion 54), the small-diameter portion 63 does not come into contact with the end portion 51a of the shaft portion 51 and receive external force from the end portion 51a.

[0039] A first circular recess 65 is formed on the inner end surface 64 of the first bearing member 43A facing the second bearing member 43B (see Figures 6(A) and 6(B)). A second circular recess 67 is formed on the inner end surface 66 of the second bearing member 43B facing the first bearing member 43A (see Figures 7(A) and 7(B)). These first circular recess 65 and second circular recess 67 are each formed in a circular shape when viewed from the axial direction of the drive shaft 42 and are located on the same axis as the shaft hole 61. Furthermore, the first circular recess 65 and the second circular recess 67 are formed to have the same opening diameter and are stacked so that their openings face each other. By stacking the first circular recess 65 and the second circular recess 67 facing each other in this way, an oil reservoir 68 is formed, which is a space that communicates with the shaft hole 61. Although not shown, the oil reservoir 68 is filled with lubricating oil.

[0040] As shown in Figure 6(B), the first shaft hole 61A of the first bearing member 43A in this embodiment is composed of a first large-diameter hole 71 opening into the first circular recess 65 and a first small-diameter hole 72 opening at the end of the first bearing member 43A adjacent to the crank body 41. The diameter of the first large-diameter hole 71 is such that an annular space S1 is formed between it and the drive shaft 42. The diameter of the first small-diameter hole 72 is such that the drive shaft 42 can slide rotatably. The annular space S1 between the first large-diameter hole 71 and the drive shaft 42 constitutes a first oil passage 73 for flowing lubricating oil from the first circular recess 65 to the first small-diameter hole 72 located on one side in the axial direction of the drive shaft 42.

[0041] As shown in Figure 7(B), the second shaft hole 61B of the second bearing member 43B is composed of a second large-diameter hole 74 that opens into the second circular recess 67 and a second small-diameter hole 75 formed within the small-diameter portion 63 of the second bearing member 43B. The diameter of the second large-diameter hole 74 is such that an annular space S2 is formed between it and the drive shaft 42. The second small-diameter hole 75 is a non-through hole. The diameter of the second small-diameter hole 75 is such that the drive shaft 42 can slide rotatably. The annular space S2 between the second large-diameter hole 74 and the drive shaft 42 constitutes a second oil passage 76 for flowing lubricating oil from the second circular recess 67 to the second small-diameter hole 75 located on the other side in the axial direction of the drive shaft 42.

[0042] (Explanation of diaphragm pump operation) In the diaphragm pump 11 configured in this way, the rotation of the motor shaft 14 of the motor 12 causes the crank body 41 and the drive shaft 42 to rotate around the rotation shaft 14. At this time, the drive body 44 oscillates in accordance with the change in the direction of inclination of the drive shaft 42, because its rotation is restricted by the diaphragm 17. This oscillating motion causes the arm portion 52 to push and pull the deformable portion 21 of the diaphragm 17. As a result, the drive body 44 converts the rotation of the rotation shaft 14 into reciprocating motion and transmits it to the deformable portion 21 of the diaphragm 17. As the deformable portion 21 is pulled toward the motor 12 by the arm portion 52 and expands, the volume of the pump chamber 22 increases, the intake valve 24 opens, and air is drawn into the pump chamber 22 from the intake pipe 27 through the intake passage 25.

[0043] Meanwhile, the deformed portion 21 of the diaphragm 17 is pushed toward the valve holder 18 by the arm portion 52, causing the deformed portion 21 to contract and reducing the volume of the pump chamber 22. This opens the discharge valve 34, and the air in the pump chamber 22 is discharged through the discharge passage 26 and out of the discharge pipe 33. As the crank body 41 rotates continuously, the pump mechanism 36 alternates between a state in which air is discharged from the pump chamber 22 and a state in which air is drawn into the pump chamber 22.

[0044] When the diaphragm pump 11 operates in this manner, the drive shaft 42 rotates while in contact with the first small-diameter hole 72 of the first bearing member 43A and the second small-diameter hole 75 of the second bearing member 43B. In other words, the drive shaft 42 slides relative to the shaft hole 61. An oil reservoir 68 opens into the shaft hole 61. The lubricating oil in the oil reservoir 68 flows through the first and second oil passages 73 and 76, which are formed by the minute gap between the drive shaft 42 and the first and second large-diameter holes 71 and 74, to reach the first and second small-diameter holes 72 and 75 and lubricate them. In this way, lubricating oil can be supplied to the first and second small-diameter holes 72 and 75 from the oil reservoir 68.

[0045] In this embodiment, the drive unit 44 is not provided with a shaft hole into which the drive shaft 42 is rotatably fitted. Therefore, it is not necessary to perform the coaxial adjustment that was conventionally performed on the mold used to form the drive unit 44. The coaxial adjustment is performed on the mold used to form the first bearing member 43A and the second bearing member 43B. This coaxial adjustment determines the outer diameters of the first bearing member 43A and the second bearing member 43B. The mold used to form the drive unit 44 is then adjusted to match the inner diameter of the second functional part 54. The precision required for this adjustment is the same high precision as in the conventional method, but by adopting this embodiment, it is possible to reduce the effort required for mold processing and inspection during mold creation, modification, and correction.

[0046] Furthermore, since the first and second bearing members 43A and 43B in this embodiment are formed separately from the drive body 44, they are not affected by sink marks that occur in the arm portion 52 during the molding of the drive body 44. As a result, the roundness of the first small-diameter hole 72 of the first bearing member 43A and the second small-diameter hole 75 of the second bearing member 43B can be maintained at a high degree. Therefore, according to this embodiment, it is possible to provide a diaphragm pump in which the adjustment work performed on the mold for molding the drive unit 44 is simplified and the wear resistance of the bearing portion is improved.

[0047] The oil reservoir 68 in this embodiment is formed by a first circular recess 65 formed on the inner end face 64 of the first bearing member 43A facing the second bearing member 43B, and a second circular recess 67 formed on the inner end face 66 of the second bearing member 43B facing the first bearing member 43A. The shaft hole 61 has first and second oil passages 73 and 76 formed so that the lubricating oil in the first and second circular recesses 65 and 67 flows axially from the first and second circular recesses 65 and 67. Therefore, lubricating oil is supplied to the first and second small-diameter holes 72 and 75, and the sliding portion between the drive shaft 42 and the first and second bearing members 43A and 43B can be lubricated. As a result, even though there are two bearing members (the first bearing member 43A and the second bearing member 43B), it becomes possible to reliably lubricate the bearing portion.

[0048] In this embodiment, the arm portion 52 of the drive body 44 is integrally formed with the end portion 51a of the shaft portion 51 opposite to the crank body 41. Of the first bearing member 43A and the second bearing member 43B, the second bearing member 43B, which is located opposite to the crank body 41, is formed in a shape that reaches the end portion 51a of the shaft portion 51 in the axial direction of the drive shaft 42. The space between the end portion 51a of the shaft portion 51 and the second bearing member 43B is an annular gap d when viewed from the axial direction of the drive shaft 42. Therefore, when adopting a configuration in which the large-diameter portion 62 of the second bearing member 43B is press-fitted into the second functional portion 54 of the shaft portion 51, no load is applied to the small-diameter portion 63 from the shaft portion 51. Furthermore, even if the end portion 51a of the shaft portion 51 deforms due to the effect of shrinkage during molding that occurs in the arm portion 52 of the drive body 44, this deformation is absorbed by the annular gap d, so no pressing force is applied to the second bearing member 43B from the end portion of the shaft portion 51. Consequently, the roundness of the small-diameter portion 63 of the second bearing member 43B can be maintained at an even higher level, and the wear resistance of the second bearing member 43B can be further improved.

[0049] (Variations of oil passages) The oil passages formed in the shaft bore can be configured as shown in Figures 8 and 9. In Figures 8 and 9, the same or equivalent components as those described in Figures 1 to 7 are denoted by the same reference numerals, and detailed explanations are omitted as appropriate. The first shaft hole 61A shown in Figure 8 has a first oil passage 81 consisting of a plurality of grooves extending from the first circular recess 65 toward the first bearing member 43A in the axial direction of the drive shaft 42. The second shaft hole 61B shown in Figure 9 has a second oil passage 82 consisting of a plurality of grooves extending from the second circular recess 67 toward the second bearing member 43B in the axial direction of the drive shaft 42. The plurality of grooves constituting the first oil passage 81 and the plurality of grooves constituting the second oil passage 82 are each formed to be arranged at predetermined intervals in the circumferential direction of the drive shaft 42. The portions of the first shaft hole 61A and the second shaft hole 61B where grooves (first and second oil passages 81 and 82) are not formed are sliding surfaces on which the drive shaft 42 can rotatably slide. Even when the oil passages are configured in this way, it is possible to ensure reliable lubrication of the bearing portion of the drive unit.

[0050] The shaft bore 61 shown in the above-described embodiment has first oil passages 73, 81 and second oil passages 76, 82, and is formed so that lubricating oil is guided from the oil reservoir 68 in both axial directions of the drive shaft 42. However, the diaphragm pump 11 according to the present invention is not limited to this, and can be configured so that lubricating oil is guided from the oil reservoir 68 in only one axial direction of the drive shaft 42. That is, the oil reservoir 68 can be formed by a circular recess formed on either the inner end surface 64 of the first bearing member 43A or the inner end surface 66 of the second bearing member 43B. Furthermore, the oil passages of the shaft bore 61 can be formed so as to extend from the first and second circular recesses 65, 67 in one or the other axial direction of the drive shaft 42.

[0051] The diaphragm pump 11 shown in the above-described embodiment is a three-cylinder type equipped with three pump chambers 22. However, the present invention is not limited to such limitations. That is, the number of cylinders in the diaphragm pump according to the present invention can be changed as appropriate, such as single-cylinder, two-cylinder, four-cylinder or more. [Explanation of symbols]

[0052] 11...Diaphragm pump, 12...Motor, 14...Rotating shaft, 17...Diaphragm, 22...Pump chamber, 21...Deformed part, 36...Pump mechanism, 41...Crank body, 42...Drive shaft, 43...Bearing member, 43A...First bearing member, 43B...Second bearing member, 44...Drive unit, 51...Shaft part, 52...Arm part, 61...Shaft hole, 61A...First shaft hole (through hole), 61B...Second shaft hole (non-through hole), 64, 66...Inner end face, 65...First circular recess, 67...Second circular recess, 68...Oil reservoir, 71...First large diameter hole, 73...First oil passage, 74...Second large diameter hole, 76...Second oil passage, d...Annular gap.

Claims

1. A diaphragm having a deformable portion that forms part of the wall of the pump room, A crank body fixed to the motor's rotating shaft, The aforementioned crank body has one end fixed to an eccentric position and is inclined, A drive unit is rotatably supported on the drive shaft via a bearing member, and converts the rotation of the crank body into reciprocating motion and transmits it to the deformation part. The pump mechanism comprises a drive unit that, in conjunction with the reciprocating motion of the drive unit, alternately repeats a state in which fluid is discharged from the pump chamber and a state in which fluid is drawn into the pump chamber. The drive unit has a shaft portion that houses and holds the bearing member in a fitted state, and an arm portion that protrudes radially outward from the shaft portion and is connected to the deformed portion. The bearing member is composed of a first bearing member and a second bearing member that are stacked on top of each other in an axial direction of the drive shaft. The first bearing member and the second bearing member are formed in a cylindrical shape having an axial hole into which the drive shaft is rotatably fitted, The shaft hole of the first bearing member adjacent to the crank body is formed as a through hole, and the shaft hole of the second bearing member is formed as a non-through hole. An oil reservoir is formed at the boundary between the first bearing member and the second bearing member, opening over the entire circumferential direction of the shaft hole. The arm portion of the drive body is integrally formed with the end of the shaft portion opposite to the crank body, The diaphragm pump is characterized in that the second bearing member has a large-diameter portion that fits into the shaft portion and a small-diameter portion that is formed to loosely fit with the end portion of the shaft portion.

2. In the diaphragm pump according to claim 1, The aforementioned oil reservoir section is, The end face of the first bearing member facing the second bearing member, It is formed by a circular recess formed on at least one of the end faces of the second bearing member and the end face facing the first bearing member, The diaphragm pump is characterized in that the shaft bore has an oil passage formed so that the lubricating oil in the circular recess flows from the circular recess in at least one direction in the axial direction.

3. In the diaphragm pump according to claim 1 or claim 2, The second bearing member is formed in a shape that reaches the end of the shaft portion in the axial direction of the drive shaft, A diaphragm pump characterized in that the space between the end of the shaft portion and the second bearing member is an annular gap when viewed from the axial direction of the drive shaft.

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