JP4243595B2 - Rolling diaphragm pump - Google Patents

Description

  The present invention relates to a rolling diaphragm pump, and more particularly to a rolling diaphragm pump that can be suitably used for semiconductor and liquid crystal processes.

  The rolling diaphragm pump is configured by a piston housed in a cylinder and driven in a reciprocating manner. An inner peripheral portion of the rolling diaphragm is attached to the piston, and an outer peripheral portion thereof is attached to the cylinder, and is defined by the rolling diaphragm, the cylinder, and the piston. A fluid suction port and a discharge port are respectively opened in the pressure chamber, and the fluid suction port and the discharge port are connected to a fluid tank and a discharge fluid supply unit via check valves, respectively. When the piston is driven to reciprocate, the volume of the pressure chamber changes, fluid is sucked from the suction port in the process of increasing the volume, and fluid is discharged from the discharge port in the process of shrinking.

A rolling diaphragm made of rubber is used for this pump, and a hydraulic or pneumatic cylinder is used as a pump drive source (see, for example, “Patent Document 1”).
JP-A 61-197779

  For example, a conventional rolling diaphragm pump cannot be applied as a semiconductor or liquid crystal process pump such as a semiconductor resist solution coating pump. The reason is that since a rolling diaphragm made of rubber is used, the rolling diaphragm made of rubber is deteriorated by a resist solution, and it is difficult to ensure the quantitativeness of the pump due to the elasticity of the rolling diaphragm made of rubber. is there. Therefore, by adopting a rolling diaphragm made of a fluororesin such as polytetrafluoroethylene (PTFE) in place of the rubber rolling diaphragm, the rolling diaphragm has corrosion resistance and chemical resistance, and the rolling diaphragm has elasticity. In addition, since it is easy to ensure the quantitativeness of the pump, it can be expected to be used as a rolling diaphragm pump as a semiconductor or liquid crystal process pump.

  However, when a hydraulic pressure or pneumatic cylinder is used as the pump drive source, no rotational moment (torsional force) is applied to the rolling diaphragm, and cracks and holes are hardly generated even if the rolling diaphragm is molded with a fluororesin. In this case, since the reciprocating motion of the piston can be performed only between two fixed positions, even if a constant discharge amount and discharge speed (discharge pressure) can be obtained, they cannot be controlled, and there is a problem in general use. Produce. On the other hand, by using a linear actuator that converts the rotational movement of the motor unit into a linear movement and outputs it as a pump drive source, the stroke of the piston can be controlled, and the discharge amount and discharge speed can be changed and adjusted. In such a case, a rotational moment acts on the rolling diaphragm, and a rolling diaphragm made of a fluororesin tends to cause cracks and holes, resulting in a problem in durability. For this reason, the application of rolling diaphragm pumps to semiconductors and liquid crystal process pumps has not been realized so far.

  The purpose of the present invention is to adopt a rolling diaphragm made of a fluororesin, while ensuring the corrosion resistance and chemical resistance of the rolling diaphragm and the quantitativeness of the pump, while making the rolling diaphragm made of the fluororesin less susceptible to cracks and holes, Moreover, it is possible to change and adjust the discharge amount and discharge speed of the pump. For example, a rolling diaphragm (quantitative) excellent in durability and versatility applicable as a semiconductor or liquid crystal process pump, such as a semiconductor resist solution coating pump. To provide a pump.

For the present invention to achieve the above object, a piston reciprocatingly driven is housed in the cylinder, the inner peripheral portion is attached to the piston, on its outer circumference through the folded portions of the piston periphery the cylinder and rolling diaphragm mounted, and these cylinders, pistons and the rolling diaphragm pressure chamber defined by, in a rolling diaphragm pump having a suction port and discharge port of the fluid respectively communicating to the pressure chamber, the piston, The cylinder head side has a large diameter portion, the cylinder head side has a small diameter portion that forms a predetermined gap with the cylinder, and an outer peripheral surface of the large diameter portion The rolling diaphragm is made of a fluororesin and is guided on the tip surface of the small diameter portion of the piston. A screw shaft portion screwed into a bottomed screw hole provided axially, and an end portion of the inner peripheral portion is attached to the small diameter portion of the piston by screw connection by the screw hole and the screw shaft portion; As a pump drive source, a motor unit, a screw nut that converts the rotational motion of the motor unit into a linear motion and outputs it, and a linear motion mechanism unit including an output screw shaft screwed into the screw nut A linear actuator, and the linear actuator is coaxially attached to an end of the cylinder opposite to the cylinder head side, and one end of the output screw shaft protruding into the cylinder from the linear actuator is a large piston. Rutotomoni is coaxially coupled to the distal end of the diameter portion, also provided with detent means for restricting rotation while allowing reciprocating movement of the piston between the piston and the cylinder It is.

  According to the above configuration, since the piston is allowed to reciprocate and the rotation is restricted by the rotation preventing means provided between the piston and the cylinder, the piston can be reciprocated (directly moved) by the linear actuator. . For this reason, the piston stroke can be controlled, and the discharge amount and discharge speed of the pump can be changed and adjusted. Further, the rotation stopping means of the piston prevents the rotational moment from acting on the rolling diaphragm, and even if a rolling diaphragm made of a fluororesin is employed, cracks and holes are hardly generated.

In the present invention, detent means of said piston includes a long hole which is opened and formed along the axis in the cylinder, one end is attached to the large diameter portion of the piston, the other end through the elongated hole is the cylinder it is desirable to configure in an engaging pin to operate the piston and integrally protruded outside. Further, it is desirable to provide a sensor for detecting a predetermined position of said piston by said engagement pin protruding out of the cylinder.

  By adopting the above-described configuration, it becomes possible to detect the reference position of the piston by the sensor using the rotation preventing means when the piston stroke control (pump discharge amount and discharge speed control) is performed. For this reason, a dedicated part for detecting the piston position is not required, the number of parts can be reduced, and the size and cost of the pump can be reduced.

In the present invention, the sealing member is provided on between the sliding surfaces of the large diameter portion of the cylinder and the piston, the cylinder, the rolling diaphragm in the piston stroke end position on the side to increase the volume of the pressure chamber an air suction outlet located near the back of the folded portion is provided in, within the cylinder, it is desirable to have a negative pressure chamber on the opposite side of the pressure chamber.

  By adopting this configuration, the inner peripheral portion of the rolling diaphragm can be brought into close contact with the outer peripheral surface of the piston, and the outer peripheral portion can be brought into close contact with the inner peripheral surface of the cylinder. For this reason, even when a rolling diaphragm made of a fluororesin is employed, it is possible to prevent the cross-sectional shape of the inner peripheral portion and the outer peripheral portion of the rolling diaphragm from being deformed into, for example, a polygon and causing wrinkles. This also makes it difficult for cracks or holes to occur in the rolling diaphragm made of a fluororesin. In addition, by providing an air suction port near the back of the folding part of the rolling diaphragm, the above functions can be exerted with good responsiveness almost simultaneously with the start of the pump, and cracks, holes, etc. are generated in the rolling diaphragm made of fluororesin. Can be effectively suppressed. Further, the sliding powder of the seal member provided between the sliding surfaces of the cylinder and the piston can be sucked out and discharged from the air suction port. For this reason, it is possible to prevent the sliding powder and the like from entering and accumulating between the inner peripheral portion of the rolling diaphragm and the outer peripheral surface of the piston or between the outer peripheral portion of the rolling diaphragm and the inner peripheral surface of the cylinder. This also makes it difficult for cracks or holes to occur in the rolling diaphragm made of a fluororesin. With regard to this function as well, by providing an air suction port in the vicinity of the back of the folding part of the rolling diaphragm, it can be effectively exerted, and it is possible to effectively suppress the generation of cracks or holes in the rolling diaphragm made of fluororesin. be able to.

  According to the present invention, a rolling diaphragm made of a fluororesin is employed to ensure the chemical resistance and quantification of the pump, while the rolling diaphragm made of the fluororesin is hardly cracked or perforated, and the pump discharge To provide a rolling diaphragm (quantitative) pump excellent in durability and versatility that can be applied as a semiconductor or liquid crystal process pump, such as a semiconductor resist solution coating pump, which can change and adjust the amount and discharge speed. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a rolling diaphragm pump in a suction state according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a discharging state of the rolling diaphragm pump.

  In this rolling diaphragm pump, a piston 2 is accommodated in the cylinder 1 so as to be movable in the axial direction, and a reciprocating motion is given to the piston 2 by a pump drive source and rotation preventing means described later. The piston 2 is formed so that a substantially half portion on the opposite side to the cylinder head side is formed to be substantially the same diameter as the cylinder inner diameter, and a substantially half portion on the cylinder head side is formed with a cylinder inner diameter so as to form a predetermined gap with the cylinder 1. It has a stepped structure with a smaller diameter, a large diameter portion 2a and a small diameter portion 2b, and is slidably guided in the axial direction along the inner peripheral surface of the cylinder 1 on the outer peripheral surface of the large diameter portion 2a. . The outer peripheral surfaces of the large diameter portion 2a and the small diameter portion 2b are connected by an inclined surface (taper surface) 2c that gradually decreases in diameter from the large diameter portion 2a toward the small diameter portion 2b.

  As shown in FIG. 3, the rolling diaphragm 3 provided in the rolling diaphragm pump includes a screw shaft that is screwed into a bottomed screw hole 2 d that is coaxially provided at the distal end surface of the small diameter portion 2 b of the piston 2. Part 3a, flange part 3b which is formed to project radially from one outer peripheral surface on the head side of screw shaft part 3a, and is in close contact with the outer edge part of the distal end surface of small diameter part 2b of piston 2, and the end part of flange part 3a A rolling diaphragm inner peripheral portion 3c extending in the axial direction along the outer peripheral surface of the distal end portion of the small-diameter portion b of the piston 2 and closely contacting the outer peripheral surface of the distal end portion of the small-diameter portion 2b of the piston 2, and the rolling diaphragm It extends in the axial direction from the end of the inner peripheral portion 3c through the U-shaped folded portion 3d along the inner peripheral surface of the cylinder 1 on the cylinder head side, and is in close contact with the inner peripheral surface of the cylinder 1 on the cylinder head side. A thin-film rolling diaphragm outer peripheral portion 3e, and a ring portion 3f extending in a radial direction from an end portion of the rolling diaphragm outer peripheral portion 3e and sandwiched between the cylinder 1 and a cylinder head (pump head) 1a at one end thereof The head 3g having a two-face notch structure is provided so as to project from one end face on the head side of the screw shaft portion 3a and for fitting a tool such as a wrench when the screw shaft 3a is screwed into the screw hole 2d. A pressure chamber 4 is defined on the cylinder head side in the cylinder 1 by the rolling diaphragm 3 (piston 2) and the cylinder 1. An O-ring 5 made of fluoro rubber as a seal member is provided between the joint surfaces of the cylinder 1 and the ring portion 3f. FIG. 3 shows the rolling diaphragm 3 when the piston 2 moves to the stroke end position in the suction process, and the rolling diaphragm outer peripheral portion 3e is greatly swollen with respect to the rolling diaphragm inner peripheral portion 3c. Yes. A rolling diaphragm pump is provided with a rolling diaphragm 3 in which the state shown in FIG.

  In the cylinder head 1a, a fluid suction port 6 and a discharge port 7 communicating with the pressure chamber 4 are opened, and the suction port 6 is connected to a liquid tank via a pipe line provided with a suction side air operated valve (not shown). The discharge port 7 is communicatively connected to the discharge liquid supply unit via a pipe line provided with a discharge side air operated valve (not shown). At the time of discharge, only the discharge side air operation valve is opened and the suction side air operation valve is closed. At the time of suction, the discharge side air operation valve is closed and only the suction side air operation valve is opened.

  In the above configuration, when the piston 2 is reciprocated by the pump drive source and the rotation preventing means, which will be described later, and the piston 2 is reciprocated in the cylinder 1, the volume of the pressure chamber 4 is increased. In the right-hand process in FIGS. 1 and 2, the liquid in the liquid tank is sucked into the pressure chamber 4 and the volume of the pressure chamber 4 is reduced (the left-hand process in FIGS. 1 and 2). Thus, the liquid in the pressure chamber 4 is supplied to the discharge liquid supply unit. Therefore, the liquid in the liquid tank can be supplied to the discharge liquid supply unit by the reciprocating drive of the piston 1.

  In the rolling diaphragm pump configured as described above, at least the liquid contact portion, that is, the cylinder head 1a and the rolling diaphragm 3 are formed of a fluororesin such as polytetrafluoroethylene (PTFE), whereby the liquid contact portion In addition to providing corrosion resistance and chemical resistance to the rolling diaphragm 3, the rolling diaphragm 3 is not stretchable and facilitates ensuring the quantitativeness of the pump. This rolling diaphragm pump can be used, for example, as a semiconductor resist solution coating pump (resist solution The pump is configured to be used as a semiconductor or liquid crystal process pump, such as a pump for supplying a constant discharge amount and discharge speed from the storage tank to the resist outlet.

  Further, the rolling diaphragm pump is provided with a linear actuator 8 as a pump drive source so that the discharge amount and discharge speed of the pump can be changed and adjusted by the stroke control of the piston 2. The linear actuator 8 includes a multi-phase (for example, five-phase) stepping motor unit 9 and a linear motion mechanism unit 10 that converts the rotational motion of the motor unit 9 into linear motion and outputs the linear motion. The motor unit 9 includes a hollow rotating shaft 11, a rotor 12 attached to the outer peripheral surface of the rotating shaft 11, and a stator 13 provided around the rotor 12. The rotating shaft 11 has a stepped structure including a small-diameter portion 11a supported by a bearing 14 and a large-diameter portion 11b supported by a bearing 15 that receives both thrust load and radial load, and rotates to the small-diameter portion 11a. A screw nut 16 (to be described later) is disposed in the large-diameter portion 11b while the child 12 is attached. The inner side of the bearing 15 is fixed to the large-diameter portion 11b by a lock nut 17 that is screwed onto the outer peripheral surface of the end portion of the large-diameter portion 11b. In this configuration, in the motor unit 9, the rotating shaft 11 rotates together with the rotor 12 with energization of a stator winding (not shown).

An output screw shaft (ball screw shaft) 18 is coaxially penetrated through the hollow portion of the rotating shaft 11, and a screw nut (ball screw nut) 16 screwed into the output screw shaft 18 is inserted into the large diameter portion 11b. Has been inserted. The screw nut 16 has a flange portion 16 a that protrudes in the radial direction from the open end of the rotary shaft 11 on the large diameter portion 11 b side, and the flange portion 16 a is fixed to the lock nut 17 via a bolt 28 . In this configuration, the screw nut 16 can rotate together with the rotating shaft 11.

  The output screw shaft 18 is linearly moved in the axial direction along with the rotation of the screw nut 16 by restricting the rotation about the axis thereof by a rotation preventing means described later. Therefore, in the linear actuator 8, the rotational motion of the rotary shaft 11 is converted into the linear motion of the output screw shaft 18.

  The linear actuator 8 is coaxially attached to the end of the cylinder 1 opposite to the cylinder head, and one end of the output screw shaft 18 is coaxially screwed to the tip of the piston 2 on the large diameter portion 2a side. They are connected together. That is, the output screw shaft 18 of the linear actuator 8 is configured to serve as a piston rod.

  By the way, since the piston 2 is connected to the cylinder 1 via the rolling diaphragm 3, the rolling diaphragm 3 also regulates the rotation about the same axis line of the piston 2 and the output screw shaft 18 coupled thereto. In this case, however, a rotational moment (twisting force) acts on the rolling diaphragm 3, and cracks, holes, and the like are generated in the rolling diaphragm 3 made of a fluororesin.

  Therefore, in the present embodiment, a detent means is provided between the piston 2 and the cylinder 1 in the rolling diaphragm pump to allow the piston 2 to reciprocate and restrict the rotation. Specifically, the anti-rotation means includes a long hole 19 formed in the side wall of the cylinder 1 along the axis, and one end screwed and fixed to the outer peripheral surface of the distal end side of the large diameter portion 2a of the piston 2, The engagement pin 20 is mounted in a protruding shape in the radial direction from the outer peripheral surface of the distal end side of the large-diameter portion 2a, and the other end protrudes out of the cylinder 1 through the long hole 19 of the cylinder 1. In this configuration, the engagement pin 20 reciprocates integrally with the piston 2.

  In the above configuration, the rotation of the piston 2 around the axis is restricted, and the piston 2 can reciprocate in the axial direction within the range of the long hole 19, and the output screw shaft 18 coupled integrally with the piston 2 and Rotation about the axis of the rolling diaphragm 3 made of fluororesin is also restricted at the same time, and cracks or holes are generated in the rolling diaphragm 3 made of fluororesin without giving a rotational moment to the rolling diaphragm 3 made of fluororesin. The piston 2 can be reciprocated by the linear actuator 8 while preventing the above. For this reason, a piston stroke can be controlled and the discharge amount and discharge speed of a pump can be changed and adjusted.

  Further, the rolling diaphragm pump is provided with a sensor 21 for detecting a reference position of the piston 2 when performing stroke control (pump discharge amount and discharge speed control) of the piston 2. As shown in FIG. 4, the sensor 21 is attached to the light emitting element 21 a attached to one end of the tip of the sensor base 22 whose tip is branched in a U-shape, and to the other end of the tip of the sensor base 22. The light receiving element 21b and the light receiving element 21b disposed to face each other with a predetermined interval are photoelectrically configured. The sensor 21 is located slightly before the stroke end position in the suction process of the piston 2, and the tip of the engagement pin 20 protruding outside the cylinder 1 passes between the light emitting element 21 a and the light receiving element 21 b, and the light emitting element It is fixedly installed outside the cylinder 1 so as to block the light irradiated from 21a toward the light receiving element 21b, and this light blocking position is detected as a reference position of the piston 2.

  In the above configuration, when the stroke control of the piston 2 (pump discharge amount and discharge speed control) is performed, the reference position of the piston 2 can be detected by the sensor 21 by using the engagement pin 20 of the detent means. it can. For this reason, a dedicated component for detecting the position of the piston 2 is not required, the number of components can be reduced, and the size and cost of the pump can be reduced. As a sensor for detecting the reference position of the piston 2 by using the engaging pin 20 of the detent means, various sensors other than the photoelectric sensor 21 and switches such as limit switches are used. May be.

  In addition, the rolling diaphragm pump provided with the linear actuator 8 capable of performing highly accurate position control as a pump drive source immediately after the discharge process of the piston 2 is performed, the piston 2 is set in the discharge direction while only the discharge side air operated valve is opened. By slightly moving in the reverse suction direction, it is possible to provide a function (suck back function) for preventing liquid from dropping from the nozzle at the tip of the discharge side pipe line. For this reason, a normal pump must have a suck-back valve separately from the pump, but this rolling diaphragm pump does not require it, and the number of parts can be reduced when constructing a pump system. At the same time, in the suck back valve used separately from the normal pump, it was necessary to manually adjust each time with the screw attached to the suck back valve in order to adjust the suck back amount. Since the rolling diaphragm pump has a suck back function in the pump itself, the suck back amount and the suck back speed can be adjusted, and the suck back function is stabilized. Since the suck back amount affects the discharge amount in the next discharge step, if the suck back amount becomes stable, the discharge amount becomes more stable, and high-precision quantitative discharge can be realized.

  Further, in this rolling diaphragm pump, the large diameter portion 2a of the piston 2 is provided between the sliding surfaces of the cylinder 1 and the piston 2, that is, between the inner peripheral surface of the cylinder 1 and the outer peripheral surface of the large diameter portion 2a of the piston 2. O-ring 23 made of fluoro rubber as a seal member via an annular packing groove 2e provided adjacent to the inclined surface 2c, and polytetrafluoro provided on the outer periphery of the O-ring 23 A slipper ring 24 made of a fluororesin such as ethylene (PTFE) is provided, and the side wall of the cylinder 1 is behind the folded portion 3d of the rolling diaphragm 3 at the stroke end position in the suction process of the piston 2 (FIG. 1). The air suction port 25 is provided in the vicinity of the right side in FIG. As a result, the cylinder 1 is defined by the rolling diaphragm 3, the O-ring 23, the inner peripheral surface of the cylinder 1, and the small diameter portion 2 b of the piston 2 on the side opposite to the pressure chamber 5, and communicates with the air suction port 25. A negative pressure chamber 26 is provided. The negative pressure chamber 26 is maintained at a pressure sufficiently lower than the pressure of the pressure chamber 4 by an intake action by an aspirator (vacuum generator) (not shown) connected to the air suction port 25.

  In the above configuration, the rolling diaphragm 3 includes the rolling diaphragm inner peripheral portion 33c on the outer peripheral surface of the distal end portion of the small diameter portion 2b of the piston 3, and the rolling diaphragm outer peripheral portion 3e on the inner peripheral surface on the cylinder head side of the cylinder 1, respectively. Since it can make it contact | adhere, it can prevent that the cross-sectional shape of the inner peripheral part 3c and the outer peripheral part 3e of the rolling diaphragm 3 which consists of a fluororesin deform | transforms into a polygon, for example, and a wrinkle is produced. This also makes it difficult for cracks or holes to occur in the rolling diaphragm 3 made of a fluororesin. Further, by providing the air suction port 25 in the vicinity of the back of the folded portion 3d of the rolling diaphragm 3, the above function can be exerted with high responsiveness almost simultaneously with the start of the pump, and the rolling diaphragm 3 made of fluororesin has cracks and holes. Etc. can be effectively suppressed. Further, since the sliding powder and the like of the slipper ring 24 on the outer periphery of the O-ring 23 which is a sealing member provided between the sliding surfaces of the cylinder 1 and the piston 2 can be sucked and discharged from the air suction port 25, the rolling The sliding powder enters between the diaphragm inner peripheral portion 3c and the outer peripheral surface of the distal end portion of the small diameter portion 2b of the piston 2 or between the rolling diaphragm outer peripheral portion 3e and the inner peripheral surface of the cylinder 1 on the cylinder head side. Can be prevented. This also makes it difficult for cracks or holes to occur in the rolling diaphragm 3 made of a fluororesin. With respect to this function, the air suction port 25 can be effectively provided by providing the air suction port 25 in the vicinity of the back portion 3d of the rolling diaphragm 3, and the rolling diaphragm 3 made of a fluororesin can be cracked or holed. It can be effectively suppressed.

  The rolling diaphragm pump of the present embodiment configured as described above employs a rolling diaphragm 3 made of a fluororesin, so that the rolling diaphragm 3 made of a fluororesin is secured while ensuring chemical resistance and quantitativeness of the pump. Durability and versatility can be used as semiconductor and liquid crystal process pumps, such as semiconductor resist solution coating pumps, etc. It is an excellent rolling diaphragm (quantitative) pump.

  As mentioned above, although this Embodiment showed an example of the suitable embodiment of this invention, this invention is not limited to it, Various modifications can be implemented within the range which does not deviate from the summary.

  For example, in the present embodiment, a semiconductor resist solution supply pump is used as an example, but it can be used as various other liquid metering pumps, and is particularly suitable as a liquid metering pump having corrosive properties. is there. Further, a linear actuator having a structure different from that of the illustrated linear actuator 8 may be used as a pump drive source.

It is a longitudinal cross-sectional view of the suction state of the rolling diaphragm pump which shows embodiment of this invention. It is a longitudinal cross-sectional view of the discharge state of the rolling diaphragm pump. It is a longitudinal cross-sectional view of a push type rolling diaphragm. It is explanatory drawing of the reference position detection part of a piston.

Explanation of symbols

1 cylinder 2 piston
2a Large diameter part
2b Small diameter part
2d Screw hole 3 Rolling diaphragm
3a Screw shaft portion 3c Rolling diaphragm inner peripheral portion 3d Rolling diaphragm folded portion 3e Rolling diaphragm outer peripheral portion 4 Pressure chamber 6 Suction port 7 Discharge port 8 Linear actuator (pump drive source)
9 Motor part
10 Linear motion mechanism
15 Screw nut
18 Output screw shaft 18 Output screw shaft 18
19 Long hole (non-rotating means)
20 Engagement pin (rotation stop means)
21 Sensor (for piston reference position detection)
23 O-ring (seal member)
25 Air outlet 26 Negative pressure chamber

Claims (4)

A piston 2 reciprocatingly driven is housed in the cylinder 1, an inner peripheral portion 3c is attached to the piston 2, the outer peripheral portion 3e is attached to the cylinder 1 through the piston 2 the outer circumference of the bent portion 3d a rolling diaphragm 3, these cylinders 1, a piston 2 and a rolling diaphragm 3 pressure chamber 4 which is defined by, in a rolling diaphragm pump having a suction port 6 and outlet 7 of fluid respectively communicating with the pressure chamber 4 ,
The piston 2 has a large-diameter portion 2a on the side opposite to the cylinder head side, and a small-diameter portion 2b that forms a predetermined gap with the cylinder 1 on the cylinder head side. Is slidably guided in the axial direction along the inner peripheral surface of the cylinder 1 on the outer peripheral surface of
The rolling diaphragm 3 is made of a fluororesin, and has a screw shaft portion 3a that is screwed into a bottomed screw hole 2d that is coaxially provided on a tip surface of the small diameter portion 2b of the piston 3, and the inner peripheral portion 3c. Is attached to the small-diameter portion 2b of the piston 2 by screw connection through the screw hole 2d and the screw shaft portion 3a.
As a pump drive source, a motor unit 9, a linear motion mechanism unit 10 including a screw nut 16 that converts the rotational motion of the motor unit 9 into a linear motion and outputs it, and an output screw shaft 18 screwed into the screw nut 16. comprises a linear actuator 8 with, the linear actuator 8 is coaxially mounted on the opposite end the cylinder head side of the cylinder 1, the output screw shaft protrudes from the linear actuator 8 to the cylinder 1 18 one end of which is coaxially coupled to the distal end of the large diameter portion 2a of the piston 2 Rutotomoni,
Rolling diaphragm pump, characterized in that a detent means for restricting rotation while allowing reciprocating movement of the piston 2 between the cylinder 1 and the piston 2. Detent means of the piston 2, a long hole 19 which is opened and formed along the axis on the cylinder 1, one end is attached to the large diameter portion 2a of the piston 2, the other end through the elongated hole 19 rolling diaphragm pump of claim 1 wherein the configuration at the engagement pin 20 which operates integrally with the piston 2 that protrudes to the outside the cylinder 1. Rolling diaphragm pump according to claim 2, further comprising a sensor 21 for detecting a predetermined position of the piston 2 by the engagement pin 20 that protrudes outside the cylinder 1. The sealing member 23 is provided on between the sliding surfaces of the large diameter portion 2a of the cylinder 1 and the piston 2, the cylinder 1, the rolling diaphragm in the piston stroke end position on the side to increase the volume of the pressure chamber 4 The air suction port 25 located in the back vicinity of the 3 folding | turning part 3b is provided, and the negative pressure chamber 26 is provided in the said cylinder 1 on the opposite side to the said pressure chamber 4 , The any one of Claim 1 thru | or 3 Rolling diaphragm pump.

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