阅读说明：本技术 旋转隔膜泵 (Rotary diaphragm pump ) 是由 手岛一清 浦田大辅 于 2018-11-06 设计创作，主要内容包括：提供一种能够以简易的结构抑制成本提高的旋转隔膜泵。旋转隔膜泵(1)具有：壳体(2)；活塞(3),其配置为能够相对于上述壳体的内周面滑动,能够在轴向上往返移动；旋转隔膜(4),其具有可动部(41)、固定部(42)以及挠性的连结部(43),所述可动部(41)配置于活塞(3)的轴向一端部,能够与活塞(3)一体地往返移动,所述固定部(42)固定于壳体(2),所述连结部(43)将可动部(41)和固定部(42)连结；泵室(5),其在壳体(2)内的轴向一侧由旋转隔膜(4)划分形成,因伴随着活塞(3)的往返移动的连结部(42)的变形而使得室内的容积变化,由此将移送流体吸入及排出；以及工作流体室(6),其在壳体(2)内的轴向另一侧由活塞(3)的轴向另一端部划分形成,相对于室内对工作流体进行供给/排出,由此使得活塞(3)往返移动。(Provided is a rotary diaphragm pump which can be configured in a simple manner and can suppress an increase in cost. A rotary diaphragm pump (1) is provided with: a housing (2); a piston (3) that is disposed slidably with respect to the inner peripheral surface of the housing and is capable of reciprocating in the axial direction; a rotary diaphragm (4) having a movable portion (41), a fixed portion (42), and a flexible connecting portion (43), the movable portion (41) being disposed at one axial end of the piston (3) and being capable of moving back and forth integrally with the piston (3), the fixed portion (42) being fixed to the housing (2), the connecting portion (43) connecting the movable portion (41) and the fixed portion (42); a pump chamber (5) which is formed on one axial side in the housing (2) by being partitioned by a rotating diaphragm (4), and which sucks and discharges a transfer fluid by changing the volume in the chamber due to the deformation of a connecting portion (42) accompanying the reciprocating movement of the piston (3); and a working fluid chamber (6) which is defined by the other end portion in the axial direction of the piston (3) on the other side in the axial direction in the housing (2), and which supplies/discharges a working fluid to/from the chamber, thereby causing the piston (3) to reciprocate.)

1. A rotary diaphragm pump in which, in a diaphragm pump,

the rotary diaphragm pump includes:

a housing;

a piston that is disposed slidably with respect to an inner peripheral surface of the housing and is capable of reciprocating in an axial direction of the housing;

a rotary diaphragm having a movable portion, a fixed portion, and a flexible coupling portion, the movable portion being disposed at one end portion in an axial direction of the piston and being capable of reciprocating integrally with the piston, the fixed portion being fixed to the housing, the coupling portion coupling the movable portion and the fixed portion;

a pump chamber that is defined by the rotary diaphragm on one axial side in the housing and sucks and discharges a transfer fluid by changing a volume in the chamber due to deformation of the connection portion accompanying reciprocation of the piston; and

and a working fluid chamber defined by the other end portion of the piston in the axial direction on the other axial side in the housing, and configured to supply/discharge a working fluid to/from the chamber and to reciprocate the piston.

2. A rotary diaphragm pump according to claim 1,

the piston has: a sliding portion that is slidable with respect to an inner peripheral surface of the housing; a closely attached portion to which the deformed coupling portion can be closely attached; and a connecting portion that connects the sliding portion and the closely attached portion,

the sliding portion, the adhered portion, and the connecting portion are formed of a single member.

Technical Field

The present invention relates to a rotary diaphragm pump.

Background

For example, in the production processes of semiconductors, liquid crystals, organic EL, solar cells, and the like, a rotary diaphragm pump is sometimes used as a pump for feeding a chemical solution when applying or preparing the chemical solution.

For example, as described in patent document 1, in such a rotary diaphragm pump, the volume of a pump chamber (pressure chamber) sealed by a rotary diaphragm in a cylinder is changed by the reciprocating movement of a piston housed in the cylinder, and thereby a chemical liquid is sucked into or discharged from the pump chamber.

The piston is connected to an electric motor as a driving source via a shaft and a ball screw which are coaxially disposed with respect to the axis thereof. The rotary motion of the motor is converted into linear motion by a ball screw or the like to reciprocate the piston.

Patent document 1: japanese patent laid-open publication No. 2015-98855

Disclosure of Invention

The rotary diaphragm pump requires a motor as a driving source, a ball screw for converting a rotational motion of the motor into a linear motion, and the like. Therefore, there is a problem that the structure is complicated and the cost is very high. In particular, if the discharge amount of the pump is increased, the size of the motor needs to be increased to obtain a required load, which significantly increases the cost.

The present invention has been made in view of such circumstances, and an object thereof is to provide a rotary diaphragm pump that can suppress an increase in cost with a simple structure.

The rotary diaphragm pump of the present invention comprises: a housing; a piston that is disposed slidably with respect to an inner peripheral surface of the housing and is capable of reciprocating in an axial direction of the housing; a rotary diaphragm having a movable portion, a fixed portion, and a flexible coupling portion, the movable portion being disposed at one end portion in an axial direction of the piston and being capable of reciprocating integrally with the piston, the fixed portion being fixed to the housing, the coupling portion coupling the movable portion and the fixed portion; a pump chamber that is defined by the rotary diaphragm on one axial side in the housing and sucks and discharges a transfer fluid by changing a volume in the chamber due to deformation of the connection portion accompanying reciprocation of the piston; and a working fluid chamber defined by the other end portion of the piston in the axial direction on the other axial side in the housing, the working fluid chamber being configured to supply/discharge a working fluid to/from the chamber, thereby reciprocating the piston.

According to the present invention, if the working fluid is supplied to and discharged from the working fluid chamber, the piston reciprocates, and the volume in the pump chamber changes due to the deformation of the rotary diaphragm accompanying the reciprocation, whereby the transfer fluid can be sucked and discharged. Accordingly, since the conventional motor, ball screw, or the like is not required, the rotary diaphragm pump can be formed into a simple structure, and cost increase can be suppressed.

Preferably, the piston has: a sliding portion that is slidable with respect to an inner peripheral surface of the housing; a closely attached portion to which the deformed coupling portion can be closely attached; and a coupling portion that couples the sliding portion and the attached portion, wherein the sliding portion, the attached portion, and the coupling portion are formed of a single member.

In this case, since the sliding portion and the adhered portion are integrally formed via the connecting portion, it is not necessary to connect the sliding portion and the adhered portion by the connecting means or to provide a locking portion for locking the connecting means with the sliding portion and the adhered portion. This can suppress the occurrence of strain in the sliding portion and the closely contacted portion due to a load concentrated on the locking portion during the reciprocating movement of the piston. Further, since the sliding portion, the connecting portion, and the closely attached portion are formed of a single member, the piston can be easily manufactured.

Effects of the invention

According to the present invention, cost increase can be suppressed with a simple configuration.

Drawings

Fig. 1 is a perspective view of a rotary diaphragm pump according to an embodiment of the present invention.

Fig. 2 is a sectional view of the rotary diaphragm pump showing a state where the piston is at the discharge end position.

Fig. 3 is a partially enlarged sectional view of the rotary diaphragm pump of fig. 2.

Fig. 4 is a sectional view of the rotary diaphragm pump showing a state where the piston is at the suction end position.

Fig. 5 is an enlarged cross-sectional view of the portion I of fig. 2.

Fig. 6 is a sectional view showing the rotary diaphragm pump in a state in which the piston is just about to reach the most advanced position.

Fig. 7 is an enlarged perspective view of a main portion of fig. 1 showing a mounting structure of the proximity sensor.

Fig. 8 is an enlarged cross-sectional view of a main portion of fig. 2 showing a mounting structure of the proximity sensor.

Fig. 9 is an enlarged oblique view showing a modification of the mounting structure of the proximity sensor.

Fig. 10 is a sectional view of the rotary diaphragm pump showing a state where the piston is at the most advanced position.

Fig. 11 is an enlarged sectional view of a portion II of fig. 10.

Fig. 12 is a partially enlarged sectional view of a rotary diaphragm pump according to another embodiment of the present invention.

Fig. 13 is a partially enlarged sectional view of a rotary diaphragm pump according to another embodiment of the present invention.

Fig. 14 is a partially enlarged sectional view of a rotary diaphragm pump according to another embodiment of the present invention.

Detailed Description

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a perspective view of a rotary diaphragm pump according to an embodiment of the present invention. Fig. 2 is a sectional view of the rotary diaphragm pump. In fig. 1 and 2, a rotary diaphragm pump 1 includes a housing 2, a piston 3, and a rotary diaphragm 4. In the present embodiment, the longitudinal direction (axial direction) of the rotary diaphragm pump 1 (hereinafter, also simply referred to as pump 1) is arranged in the vertical direction, but may be arranged in the horizontal direction.

[ Structure of case ]

The housing 2 has a cylinder 11 and a pump head 12. The cylinder 11 has: a cylinder main body 13 formed in a cylindrical shape; and a disk-shaped bottom plate 14 fixed to the axial lower end of the cylinder main body 13. The cylinder main body 13 and the bottom plate 14 are made of metal such as aluminum, for example.

The cylinder main body 13 includes: a 1 st flange portion 13a integrally formed on an outer periphery of an axial upper end portion; and a 2 nd flange portion 13b integrally formed on an outer periphery of the axial lower end portion.

The 1 st flange portion 13a is formed in a regular quadrilateral shape, for example, and insertion holes 13c penetrating in the thickness direction (vertical direction) are formed in four corners thereof, respectively. The 2 nd flange 13b is formed in a circular ring shape, for example. The cylinder body 13 is formed with a vent hole 15 penetrating in the thickness direction (left-right direction). The vent 15 is connected to a pressure reducing device (not shown) such as a vacuum pump or a suction device.

A supply/discharge port 16 for supplying/discharging pressurized air and depressurized air into/from the casing 2 is formed in the bottom plate 14. One end of the supply/discharge port 16 opens at the center of the upper surface of the bottom plate 14, and the other end of the supply/discharge port 16 opens at the outer peripheral surface of the bottom plate 14. The other end of the supply/discharge port 16 is not shown, but is connected to any one of an air supply device such as an air compressor for supplying pressurized air and a pressure reducing device such as a vacuum pump or a suction device for forcibly discharging pressurized air by switching a valve.

The pump head 12 is formed in a cylindrical shape with a cover from a fluororesin such as Polytetrafluoroethylene (PTFE), for example. The pump head 12 is disposed on the upper surface of the 1 st flange portion 13a of the cylinder main body 13 so as to close the opening of the cylinder main body 13. The pump head 12 has substantially the same inner diameter as the cylinder main body 13. Thus, the internal space of the pump head 12 and the internal space of the cylinder main body 13 together constitute an accommodation space in which the piston 3 can be accommodated.

A flange plate 17 made of metal (e.g., stainless steel such as SUS 304) is attached to an axial upper end surface of the pump head 12. The flange plate 17 is formed in a square shape, for example, so as to have substantially the same outer shape as the 1 st flange portion 13a of the cylinder body 13. Insertion holes 17a penetrating in the thickness direction (vertical direction) are formed at four corners of the flange plate 17.

A single connection port 18 and a plurality of connection ports 19 are formed through the axial upper end portion of the pump head 12 in the thickness direction. The connection port 18 is used as a discharge port for discharging a liquid in the pump chamber 5 (described later) for the purpose of discharging air or the like. The connection port 19 functions as a suction port for sucking liquid into the pump chamber 5 or a discharge port for discharging liquid from the pump chamber 5.

One end of a cylindrical connector 21 having male screws cut at both ends is attached to the connection port 18 by passing through the flange plate 17. A nut for fixing a pipe inserted into the connector 21 is attached to the other end of the connector 21. Similarly, a flange plate 17 is inserted through one end of a cylindrical connector 22 having male screws cut at both ends thereof and is attached to the connection port 19. A nut for fixing a pipe inserted into the connector 22 is attached to the other end of the connector 22. In the present embodiment, 4 connection ports 19 and 4 connectors 22 are provided, respectively. The number of the connection ports 18 (connectors 21) and the connection ports 19 (connectors 22) is not limited to that in the present embodiment. The method of connecting the pipes is not limited to the present embodiment.

A connector 22 (for example, a connector 22a shown in fig. 1) attached to the connection port 19 serving as the suction port is not shown, and is connected to a liquid container for storing a liquid (transfer fluid) such as a chemical solution via a tube, a valve, or the like. A connector 22 (for example, a connector 22b shown in fig. 1) attached to the connection port 19 serving as the discharge port is not shown, and is connected to a liquid supply portion such as an ejection nozzle to which the liquid is applied via a tube, a valve, or the like.

[ Structure of piston ]

The piston 3 is disposed slidably with respect to the inner peripheral surface of the housing 2 and is disposed to be reciprocally movable in the axial direction (vertical direction) of the housing 2. The piston 3 is formed in a cylindrical shape by a single member made of synthetic resin such as polypropylene (PP), for example. A through hole 3a concentric with the axial center is formed in the center of the piston 3 so as to penetrate in the axial direction.

The piston 3 of the present embodiment includes a sliding portion 31 (lower cross-sectional portion in fig. 2), a connecting portion 32 (cross-sectional portion in fig. 2), and an attached portion 33 (upper cross-sectional portion in fig. 2) in this order from the axial lower end toward the axial upper end. In fig. 2, for convenience of explanation, the boundary between the sliding portion 31 and the coupling portion 32 and the boundary between the coupling portion 32 and the adhered portion 33 are indicated by virtual lines (two-dot chain lines) (the same applies to fig. 3, 4, 6, 8, 10, and 11).

Fig. 3 is a partially enlarged sectional view of the pump 1 of fig. 2. The sliding portion 31 of the piston 3 has an outer diameter slightly smaller than the inner diameter of the cylinder body 13, and an annular minute gap is formed between the outer peripheral surface 31a of the sliding portion 31 and the inner peripheral surface 13d of the cylinder body 13.

An annular seal groove 31b is formed over the entire circumference of the outer circumferential surface 31a of the sliding portion 31, and an O-ring seal 34 is attached to the seal groove 31 b. The O-ring 34 is made of a rubber material such as fluororubber. A slide ring 35 is fitted in the seal groove 31b radially outward of the O-ring 34, and the sliding portion 31 and the slide ring 35 are sealed by the elastic force of the O-ring 34 (see also fig. 11). The outer diameter of the slide ring 35 is set to be slightly larger than the inner diameter of the cylinder body 13, and the outer peripheral surface of the slide ring 35 slides while being pressed against the inner peripheral surface 13d of the cylinder body 13, so that the two peripheral surfaces are sealed, and the working fluid chamber 6 and the decompression chamber 7, which will be described later, can be separated from each other. Further, the outer diameter of the seal groove 31b of the sliding portion 31 (the diameter of the outer peripheral surface of the seal groove 31b as the bottom surface) is preferably substantially the same as the outer diameters of the coupling portion 32 and the adhered portion 33.

The closely attached portion 33 is formed as a portion where a coupling portion 43 described later is closely attached to the outer peripheral surface 33a thereof. The closely contacted portion 33 of the present embodiment has an outer diameter smaller than that of the sliding portion 31, and an annular gap is formed between the outer peripheral surface 33a of the closely contacted portion 33 and the inner peripheral surface 13d of the cylinder main body 13. The closely attached portion 33 is formed to be longer than the sliding portion 31 in the axial direction (see fig. 2). A recess 33b having a shape along the outer shape of the lower surface of the movable portion 41 described later is formed on the upper surface of the closely contacted portion 33.

The coupling portion 32 is a portion integrally coupling the sliding portion 31 and the attached portion 33. The coupling portion 32 of the present embodiment has the same outer diameter as the closely attached portion 33, and an annular gap is formed between the outer peripheral surface 32a of the coupling portion 32 and the inner peripheral surface 13d of the cylinder main body 13. The coupling portion 32 is formed to be longer than the closely attached portion 33 in the axial direction (see fig. 2). The outer diameter of the coupling portion 32 is preferably the same as the outer diameter of the closely attached portion 33.

The hole diameter of the through hole 3a changes to slightly expand at the lower portion in the axial direction of the coupling portion 32 (see fig. 3). A nut 38 screwed to the rear end of the through bolt 36 is attached to the stepped surface of the diameter expansion changing portion of the through hole 3a via a washer 39. A triangular groove is provided in the diameter-expansion-varied portion of the through-hole 3a so as to cut a part of the stepped surface thereof, and an O-ring is attached to the triangular groove. This seals the through hole 3a and the gasket 39, and the through hole 3a cuts off the communication in the vertical direction at the diameter-expanded portion.

Instead of the connection portion 32, the sliding portion 31 and the attached portion 33 may be connected by a connection means such as a rod as another member. However, in this case, it is necessary to provide a locking portion (for example, a screw-fixing portion of the rod) for locking the coupling unit in each of the sliding portion 31 and the attached portion 33. Therefore, when the piston 3 reciprocates, the load is concentrated on the locking portions provided in the sliding portion 31 and the closely attached portion 33, respectively.

Therefore, if the pump 1 having the coupling means and the locking portion is used for a long time, strain may occur in the sliding portion 31 and the closely contacted portion 33. In particular, when the sliding portion 31 and the adhered portion 33 are formed of a resin material as in the present embodiment, the strain is likely to be generated. When the portion to be adhered 33 is strained, the discharge amount of the liquid from the pump 1 may change. Further, when the sliding portion 31 is strained, the sealing performance may be degraded by the O-ring 34 and the sliding ring 35 that seal between the outer peripheral surface of the sliding ring 35 and the inner peripheral surface 13d of the cylinder body 13.

In contrast, in the present embodiment, the sliding portion 31 and the closely attached portion 33 are formed integrally via the connecting portion 32, and therefore the connecting means and the locking portion are not required. This can suppress the occurrence of strain in the sliding portion 31 and the closely contacted portion 33, and therefore, it is possible to effectively suppress a change in the amount of liquid discharged from the pump 1 or a reduction in the sealing performance between the outer peripheral surface of the sliding ring 35 and the inner peripheral surface 13d of the cylinder main body 13. Further, since the sliding portion 31, the connecting portion 32, and the closely attached portion 33 are formed of a single member, the piston 3 can be easily manufactured.

[ Structure of rotating diaphragm ]

In fig. 3, the rotating diaphragm 4 is made of a fluororesin such as PTFE and is accommodated in the case 2. The rotating diaphragm 4 has: a movable portion 41 disposed at an axial upper end portion (one axial end portion) of the piston 3; an annular fixing portion 42 attached to the housing 2; and a coupling portion 43 that couples the movable portion 41 and the fixed portion 42. The rotary diaphragm 4 is configured such that the movable portion 41 reciprocates in the axial direction integrally with the piston 3 with respect to the fixed portion 42 positioned by the housing 2.

The fixing portion 42 of the rotary diaphragm 4 is fitted into an annular recess 13e formed in the upper surface of the 1 st flange portion 13a of the cylinder main body 13, and is positioned between the cylinder main body 13 and the pump head 12. In this state, as shown in fig. 2, the nuts 25 are screwed into both end portions of the through bolts 23 inserted into the insertion holes 17a of the flange plate 17 and the insertion holes 13c of the 1 st flange portion 13a via a predetermined number of coil springs 24. The fixing portion 42 is strongly sandwiched between the joint surfaces of the cylinder main body 13 and the pump head 12 and fixed to the housing 2 by tightening the nut 25. Both ends of each through bolt 23 are covered and protected by a cover 26 together with a nut 25 and a predetermined number of coil springs 24.

Returning to fig. 3, the movable portion 41 of the rotating diaphragm 4 has substantially the same outer diameter as the portion 33 of the piston 3 to be closely attached. The movable portion 41 of the present embodiment is formed in a truncated cone shape so as to gradually decrease in diameter downward, and is fitted into the concave portion 33b of the adhered portion 33. Thereby, the movable portion 41 and the piston 3 are arranged coaxially.

A screw hole 41a is formed in the lower surface of the movable portion 41, and the tip end portion of the through bolt 36 inserted into the through hole 3a of the piston 3 is screwed into the screw hole 41 a. Thus, the movable portion 41 is fixed to the closely contacted portion 33 of the piston 3, and therefore, the movable portion 41 can be moved downward together with the piston 3 in the suction step described later.

The coupling portion 43 of the rotating diaphragm 4 couples the radially inner end of the fixed portion 42 and the radially outer end of the movable portion 41. The connecting portion 43 is formed to be thin (film-like) so as to have flexibility. On the other hand, the movable portion 41 and the fixed portion 42 are formed to have a sufficiently larger thickness than the connecting portion 43 so as to have rigidity.

In the state shown in fig. 3, the coupling portion 43 is bent in a U-shape in cross section between the inner peripheral surface 13d of the cylinder body 13 and the outer peripheral surface 33a of the closely contacted portion 33. Specifically, the connecting portion 43 extends axially downward from the radially inner end of the fixed portion 42 along the inner peripheral surface 13d of the cylinder body 13, then turns back radially inward, and extends axially upward to the movable portion 41 along the outer peripheral surface 33a of the closely contacted portion 33. In this state, the coupling portion 43 is in close contact with the inner peripheral surface 13d of the cylinder body 13 and the outer peripheral surface 33a of the closely contacted portion 33.

Further, if the piston 3 moves to the most retracted position shown in fig. 4, the coupling portion 43 deforms into a cylindrical shape along the inner peripheral surface 13d of the cylinder body 13, and most of the outer peripheral surface comes into close contact with the inner peripheral surface 13 d. Then, if the piston 3 moves to the most advanced position shown in fig. 10, the connecting portion 43 deforms into a cylindrical shape along the outer peripheral surface 33a of the closely contacted portion 33, and the entire inner peripheral surface closely contacts the outer peripheral surface 33 a.

[ division chamber in case ]

In fig. 2, a pump chamber 5, a working fluid chamber 6, and a decompression chamber 7 are partitioned by a piston 3, a rotary diaphragm 4, and the like in a casing 2 of a pump 1.

The pump chamber 5 is defined by the rotary diaphragm 4 on the upper side (one side in the axial direction) in the axial direction in the housing 2, and is configured to be capable of changing the volume in the chamber.

The pump chamber 5 of the present embodiment is formed to be surrounded by the movable portion 41 and the connecting portion 43 of the rotary diaphragm 4, and the pump head 12, and is communicated with the connection port 18 and the connection port 19, respectively. The volume in the chamber of the pump chamber 5 changes due to the reciprocating movement of the piston 3.

The working fluid chamber 6 is defined by an axial lower end portion (the other axial end portion) of the piston 3 on an axial lower side (the other axial side) in the housing 2. The working fluid chamber 6 communicates with the supply and discharge ports 16. Then, in the working fluid chamber 6, pressurized air and depressurized air (working fluid) are supplied/discharged by an air supply device and a depressurization device connected through the supply/discharge port 16, and thereby the piston 3 is reciprocated in the housing 2.

The decompression chamber 7 is defined between the pump chamber 5 and the working fluid chamber 6 in the housing 2 by the piston 3, the coupling portion 43 of the rotary diaphragm 4, and the cylinder body 13. The decompression chamber 7 communicates with the vent 15. The decompression chamber 7 is decompressed to a predetermined pressure (negative pressure) by a decompression device connected through the vent 15 when the pump 1 is driven.

[ method of driving Pump ]

In the above configuration, the discharge step of supplying pressurized air into the working fluid chamber 6 to move the piston 3 upward in the axial direction and the suction step of forcibly discharging the pressurized air in the working fluid chamber 6 to the outside to reduce the pressure in the chamber to move the piston 3 downward in the axial direction are alternately repeated. This enables the liquid stored in the liquid container or the like to be supplied from the pump 1 to the liquid supply unit.

That is, in the suction step, the movable portion 41 of the rotary diaphragm 4 moves downward (changes from the state shown in fig. 2 to the state shown in fig. 4) following the return movement of the piston 3. In this process, the coupling portion 43 of the rotating diaphragm 4 rotates so that the bent position is displaced downward from a state in which it is bent in the gap between the inner peripheral surface 13d of the cylinder body 13 and the outer peripheral surface 33a of the closely contacted portion 33 until a state in which most of the outer peripheral surface is closely contacted with the inner peripheral surface 13d of the cylinder body 13. As the volume of the pump chamber 5 increases, the liquid in the liquid container is sucked into the pump chamber 5 through the connection port 18.

In the discharge step, the movable portion 41 of the rotating diaphragm 4 moves upward (changes from the state shown in fig. 4 to the state shown in fig. 2) following the outward movement of the piston 3. In this process, the coupling portion 43 of the rotating diaphragm 4 rotates so that the bending position is displaced upward from the state where the large portion of the outer peripheral surface is in close contact with the inner peripheral surface 13d of the cylinder body 13 to the state where the coupling portion bends in the gap between the inner peripheral surface 13d of the cylinder body 13 and the outer peripheral surface 33a of the closely contacted portion 33. As the volume of the pump chamber 5 is reduced, the liquid in the pump chamber 5 is discharged from each connection port 19.

In the suction step and the discharge step, the decompression chamber 7 is decompressed to a predetermined pressure (negative pressure) by a decompression device connected through the vent 15. Therefore, the coupling portion 43 of the rotating diaphragm 4 can be reliably brought into close contact with each of the inner peripheral surface 13d of the cylinder body 13 and the outer peripheral surface 33a of the closely contacted portion 33.

As described above, if the pressurized air and the depressurized air are supplied to and discharged from the inside of the working fluid chamber 6, the piston 3 moves back and forth, and the volume in the pump chamber 5 changes due to the deformation of the connecting portion 43 of the rotary diaphragm 4 accompanying the back and forth movement, whereby the liquid can be sucked and discharged. This eliminates the need for a conventional motor, ball screw, or the like, and therefore, the pump 1 can be formed in a simple configuration, and cost increase can be suppressed.

In the present embodiment, although the decompression air is supplied into the working fluid chamber 6 by the decompression device in the suction step, instead of supplying the decompression air, the supply/discharge port 16 of the working fluid chamber 6 may be opened to the atmosphere, and the piston 3 may be moved back in the axial direction downward by the pressure of the liquid in the pump chamber 5. In this case, since the movable portion 41 of the rotary diaphragm 4 moves back together with the piston 3 by the pressure of the liquid, there is no need to fix the movable portion 41 to the through bolt 36 of the piston 3. Further, since the coupling portion 43 of the rotating diaphragm 4 can be brought into close contact with the inner peripheral surface 13d of the cylinder body 13 and the outer peripheral surface 33a of the closely contacted portion 33 by the pressure of the liquid, the decompression chamber 7 and the vent 15 are not required.

[ sealing Structure of case ]

Fig. 5 is an enlarged sectional view of the portion I of fig. 2, and shows a seal structure between the joint surfaces of the cylinder main body 13 and the pump head 12 of the housing 2. In fig. 5, the fixing portion 42 of the rotary diaphragm 4 located between the joint surfaces of the cylinder main body 13 and the pump head 12 has an annular groove portion 42a formed on the upper surface thereof.

A circular ring-shaped projection 12a formed to project from the lower surface of the pump head 12 penetrates the groove 42 a. This piercing structure prevents the liquid in the pump chamber 5 from leaking to the outside from between the joining surfaces. Further, instead of the piercing structure, a lip seal structure or an O-ring seal structure may be formed, and at least 2 seal structures of the piercing structure, the lip seal structure, and the O-ring seal structure may be used together.

An annular seal groove 13f is formed in the bottom surface of the recess 13e in the 1 st flange portion 13a of the cylinder body 13, and an O-ring 27 is fitted to the seal groove 13 f. The O-ring 27 is made of a rubber material such as fluororubber, for example, and is pressed against the lower surface of the fixing portion 42. The decompression chamber 7 (see fig. 2) is sealed by the O-ring 27. Instead of the O-ring 27, lip sealing or gasket sealing may be performed, or at least 2 types of sealing methods among the O-ring 27, lip sealing, and gasket sealing may be used together.

[ mounting Structure of proximity sensor ]

In fig. 1 and 2, a plurality of (3 in the illustrated example) 1 st, 2 nd, and 3 rd proximity sensors 51, 52, and 53 that detect the sliding position of the piston 3 are attached to the outer peripheral surface of the cylinder main body 13 of the housing 2 via an attachment plate 60.

The 1 st proximity sensor 51 detects the position of the piston 3 at the end of the suction process (the position of fig. 4, hereinafter referred to as "suction end position"). The control of stopping the return movement of the piston 3, the control of stopping the return movement and starting the outward movement, and the like are executed by this detection. As shown in fig. 4, the intake end position of the piston 3 in the present embodiment is set to a position at which the piston 3 moves back to the maximum retreating position.

The 2 nd proximity sensor 52 detects the position of the piston 3 at the end of the discharge step (the position in fig. 2, hereinafter referred to as "discharge end position"). The control of stopping the forward movement of the piston 3, the control of stopping the forward movement and starting the return movement, and the like are executed by this detection. As shown in fig. 2, the discharge end position of the piston 3 in the present embodiment is set to a position when the piston 3 moves to the vicinity of the substantially center in the axial direction in the housing 2.

As shown in fig. 6, the 3 rd proximity sensor 53 detects a position (hereinafter referred to as "the most advanced position to be reached") at which the piston 3 is about to perform forward movement to the most advanced position (see fig. 10). The 3 rd proximity sensor 53 is a backup proximity sensor for use when the piston 3 moves forward to a position above the discharge end position due to a failure of the 2 nd proximity sensor 52 or the like. The proximity sensors 51 to 53 can detect the sliding position of the piston 3 to determine the remaining amount of the liquid in the pump chamber 5.

Each of the proximity sensors 51 to 53 is a magnetic proximity sensor, and detects the magnetic force of an annular permanent magnet 56 (see fig. 3) attached to the lower end portion of the piston 3. In the present embodiment, one end surface (left end surface in fig. 8) in the axial direction of each of the proximity sensors 51 to 53 is a detection surface for detecting the magnetic force of the permanent magnet 56.

The permanent magnet 56 is fitted to the outer periphery of the coupling portion 32 of the piston 3 in the decompression chamber 7, and has substantially the same outer diameter as the sliding portion 31. The permanent magnet 56 is held by the piston 3 by its own weight in a state where its lower end surface is in contact with the stepped surface 37 of the coupling portion 32 and the slide portion 31. Thereby, the permanent magnet 56 and the piston 3 move back and forth together.

FIG. 7 is an enlarged perspective view of a main part of FIG. 1 showing a mounting structure of proximity sensors 51 to 53. FIG. 8 is an enlarged sectional view of a main part of FIG. 2 showing a mounting structure of proximity sensors 51 to 53.

In fig. 7 and 8, the mounting plate 60 is a rectangular flat plate member, and is detachably mounted to the outer peripheral surface of the cylinder main body 13 by a plurality of (6 in fig. 7) screws 61.

A long hole 60a extending in the longitudinal direction of the attachment plate 60 is formed through the attachment plate 60 in the thickness direction. A pair of nuts 54, 55 screwed to the end portions of the proximity sensors 51 to 53 on the detection surface side are disposed in the elongated hole 60a in a state where the attachment plate 60 is sandwiched. Thereby, the nuts 54, 55 are fastened to fix the proximity sensors 51 to 53 to the mounting plate 60.

A guide groove 13g extending in the axial direction is formed in the outer peripheral surface of the cylinder body 13, and a nut 55 screwed to the outer end in the axial direction of each of the proximity sensors 51 to 53 is fitted into the guide groove 13 g. This regulates the rotation of the nut 55 around the axial center.

Therefore, the proximity sensors 51 to 53 can be easily fixed to the mounting plate 60 by rotating the nut 54 that is not fitted into the guide groove 13g in the tightening direction. Further, by loosening the fastening of the corresponding nut 54, the proximity sensors 51 to 53 can be moved along the guide groove 13g and the elongated hole 60 a. This allows the position of each proximity sensor 51 to 53 to be adjusted with respect to the mounting position (detection position) of the housing 2.

FIG. 9 is an enlarged perspective view showing a modification of the mounting structure of the proximity sensors 51 to 53. In fig. 9, in the present modification, the proximity sensors 51 to 53 are mounted to the outer peripheral surface of the cylinder main body 13 of the housing 2 via a mounting plate 62 so that the position adjustment is not possible. Specifically, instead of the long holes, 3 circular holes (not shown) are formed in the mounting plate 62 so as to penetrate in the thickness direction. The proximity sensors 51 to 53 are fixed to the mounting plate 62 by inserting the detection surface-side end portions of the proximity sensors 51 to 53 into the circular holes, and fastening the pair of nuts 54 and 55 in this state.

[ Structure of stopper ]

Fig. 10 is a sectional view of the pump 1 showing a state in which the piston 3 is at the most advanced position. Fig. 11 is an enlarged sectional view of a portion II of fig. 10.

In fig. 10 and 11, a stopper 28 for restricting the outward movement of the piston 3 in the axial direction above the maximum advanced position is provided on the inner circumferential surface of the housing 2. The stopper 28 is used when the piston 3 moves forward further upward than the most advanced position due to a failure of the 3 rd proximity sensor 53 or the like.

In the present embodiment, the cylinder main body 13 has an annular stopper 28 integrally formed on an inner peripheral surface thereof so as to protrude radially inward. The stopper 28 has an inner diameter larger than the outer diameter of the coupling portion 32 of the piston 3 and smaller than the outer diameter of the permanent magnet 56. The stopper 28 is formed on the inner peripheral surface of the cylinder body 13 at a position where the upper end surface of the permanent magnet 56 abuts against the lower end surface of the stopper 28 when the piston 3 moves forward to the maximum advanced position. Further, the stopper 28 may be provided as a different component with respect to the cylinder main body 13.

According to the above configuration, the stopper 28 can restrict the forward movement of the piston 3 in the axial direction upward from the maximum advanced position. When the piston 3 is at the most advanced position, the upper surface of the movable portion 41 of the rotary diaphragm 4 is located below the top surface 12b in the pump head 12.

Therefore, the stopper 28 restricts the forward movement of the piston 3 in the axial direction from the maximum advanced position, and the upper surface of the movable portion 41 can be prevented from coming into contact with the top surface 12b of the pump head 12. As a result, generation of particles (fine dust) from the movable portion 41 can be suppressed.

In the present embodiment, the permanent magnet 56 for detection of the proximity sensors 51 to 53 also functions as a member that abuts against the stopper 28, and therefore, it is not necessary to separately provide a member that abuts against the stopper 28 on the piston 3 side. This enables the pump 1 to have a simple structure.

The vent 15 is formed to penetrate radially from the outer peripheral surface of the cylinder body 13 toward the inner peripheral surface of the stopper 28 at the portion of the cylinder body 13 where the stopper 28 is formed. Accordingly, since the vent 15 is formed in a portion of the cylinder main body 13 having a large radial thickness, a decrease in rigidity of the cylinder main body 13 can be suppressed as compared with a case where the vent is formed in a portion of the cylinder main body 13 having a small radial thickness.

Further, the vent 15 may be formed above the stopper 28 of the cylinder main body 13. However, as shown in fig. 4, when the piston 3 moves back to the most retracted position, the coupling portion 43 of the rotating diaphragm 4 is in close contact with the inner peripheral surface 13d of the cylinder body 13. Therefore, when the vent hole 15 is formed above the stopper 28 of the cylinder body 13, the length L of the cylinder body 13 from the upper end surface of the stopper 28 to the upper end surface of the cylinder body 13 needs to be longer than that of the present embodiment so that the lower end portion of the coupling portion 43 in the state shown in fig. 4 is located above the vent hole 15 without the coupling portion 43 blocking the vent hole 15.

Therefore, when the vent hole 15 is formed in the portion of the cylinder main body 13 where the stopper 28 is formed as in the present embodiment, the overall length of the housing 2 in the axial direction (vertical direction) can be reduced as much as possible, compared to the case where the vent hole 15 is formed in the upper portion of the cylinder main body 13 with respect to the stopper 28.

[ others ]

The shape of the recess 33b of the piston 3 to be closely contacted 33 can be changed in various ways as shown in fig. 12 to 14, and is preferably formed in a mortar shape as in the present embodiment (see fig. 3). That is, the piston 3 and the rotary diaphragm 4 are preferably fitted to each other via tapered surfaces 33c and 41c provided on the opposing surfaces of the both (the closely contacted portion 33 and the movable portion 41). The reason for this is as follows.

The center portion of the movable portion 41 of the rotating diaphragm 4 needs to be thickened in advance to such an extent that the distal end portions of the through bolts 36 can be screwed together.

As shown in fig. 12, when the entire movable portion 41 of the rotary diaphragm 4 is thickened, the length of the coupling portion 43 is shortened, and the variable volume of the pump chamber 5 is reduced (conversely, if the length of the coupling portion 43 is set to be the same as that of the present embodiment and the variable volume of the pump chamber 5 is secured to the same extent as that of the present embodiment, the length L of the cylinder body 13 is longer than that of the present embodiment (see fig. 4), and the overall length of the housing 2 in the axial direction (vertical direction) is increased).

As shown in fig. 13, when only the center portion of the movable portion 41 of the rotating diaphragm 4 is sharply thickened, the load applied from the portion 33 of the piston 3 to be closely contacted concentrates on the corner portion 41d (including the chamfered portion) as the boundary portion (the load is applied from the corner portion 33d in a concentrated manner), and thus the movable portion 41 may break with the corner portion 41d as a starting point. The reason for this is that, when the piston 3 and the rotary diaphragm 4 are normally aligned between the opposing surfaces 33e and 41e on the outer peripheral side portions of both (the closely contacted portion 33 and the movable portion 41) and a small gap is provided between the opposing surfaces 33f and 41f on the central portion of both, the movable portion 41 is screwed to the distal end portion of the through bolt 36, and the entire periphery of the screw hole 41a is pulled toward the closely contacted portion 33.

As shown in fig. 14, even when most of the movable portion 41 of the rotating diaphragm 4 excluding the outer peripheral portion is rapidly thickened, the load applied from the portion 33 of the piston 3 to be closely contacted is concentrated on the corner portion 41d, and therefore the movable portion 41 may break starting from the corner portion 41d, as in the case shown in fig. 13.

Therefore, in the present embodiment (see fig. 3), the upper surface (inner circumferential surface of the recess 33 b) of the closely attached portion 33 is formed as the tapered surface 33c whose inner diameter increases toward the upper side in the axial direction so that the load applied from the closely attached portion 33 of the piston 3 to the movable portion 41 of the rotary diaphragm 4 is not concentrated on the corner portion 41d (including a case of chamfering). The movable portion 41 is formed with a tapered surface 41c having an outer diameter that increases toward the axial upper side, and the thickness gradually decreases from the central portion to the outer peripheral portion. The piston 3 and the rotary diaphragm 4 are fitted to each other via tapered surfaces 33c and 41c of both (the closely contacted portion 33 and the movable portion 41).

It should be understood that the embodiments disclosed herein are examples in all respects, and no limitation is imposed thereon. The scope of the present invention is indicated by the claims, and includes a range equivalent to the scope of the claims and all modifications within the scope.

Description of the reference numerals

1 rotary diaphragm pump

2 casing

3 piston

5 rotating diaphragm

6 pump chamber

7 working fluid chamber

31 sliding part

32 connecting part

33 closely adhered part

41 Movable part

42 fixed part

43 connecting part