JP2011247249A - Positive-displacement pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive displacement pump capable of efficiently driving a movable component to change the volume of a pump chamber.SOLUTION: The positive-displacement pump 1 includes a linearly-actuating moving component 33, a fixed body 34, and a moving body 12 mounted on the moving component 33 to change the volume of a pump chamber 8. The moving component 33 has a magnet 331, and the fixed component 34 includes a yoke 37 and a drive coil 38. The yoke 37 includes a shaft part 371 extending in the moving direction of the moving component 33, and a first projecting part 372 and a second projecting part 373 projecting to the side of the magnet 331 from both ends of the shaft part 371. The drive coil 38 is wound in the direction orthogonal to the moving direction of the moving component 33 around a part between the first projecting part 372 and the second projecting part 373 of the yoke 37, and is opposed to magnetic pole faces 331a, 331b of the magnet 331. The length of the magnet 331 in the moving direction of the moving component 33 is larger than that of the yoke 37.

Description

  The present invention relates to a positive displacement pump in which a movable body for changing the capacity of a pump chamber is driven by an electromagnetic actuator. More specifically, the present invention relates to a positive displacement pump that improves efficiency by improving an electromagnetic actuator and realizes reduction of power consumption and miniaturization.

  A positive displacement pump that discharges the sucked fluid from the pump chamber by expanding the volume of the pump chamber to suck the fluid into the pump chamber and reducing the volume of the pump chamber is known. Such a positive displacement pump has a movable body such as a diaphragm for changing the volume of the pump chamber, and an electromagnetic actuator for reciprocating the movable body.

  In the positive displacement pump described in Patent Document 1, the electromagnetic actuator includes a cylindrical drive coil, a moving body made of a magnetic material inserted inside the drive coil, and magnets arranged on both sides in the axial direction of the drive coil. It has. When an excitation current is supplied to the drive coil, the drive coil and the moving body function as electromagnetic coils, and the moving body moves in the axial direction by the attractive force or repulsive force of the electromagnetic coil and magnet. The movable body is attached to the moving body and is displaced by the movement of the moving body.

JP 2005-163547 A

  Here, it is generally difficult for an electromagnetic actuator that uses the attractive force or repulsive force between an electromagnetic coil and a magnet to efficiently obtain a thrust. That is, in such an electromagnetic actuator, in order to obtain a large thrust for displacing the movable body, it is necessary to increase the excitation current supplied to the drive coil or increase the number of turns of the drive coil. As a result, the power consumption and size of positive displacement pumps have been hindered.

  In view of the above problems, an object of the present invention is to provide a positive displacement pump that can efficiently drive a movable body for changing the volume of a pump chamber.

In order to solve the above problems, the positive displacement pump of the present invention is
A movable body that can move directly;
A fixed body for linearly moving the moving body;
A movable body attached to the movable body to change the capacity of the pump chamber,
Either one of the moving body and the fixed body includes a magnet having a magnetic pole surface parallel to the moving direction of the moving body,
The other of the movable body and the fixed body includes a yoke and a drive coil facing the magnetic pole surface with a certain gap in a state of being wound around the yoke,
The yoke includes a shaft portion extending in a moving direction of the moving body, a first protrusion projecting from one end portion of the shaft portion in the moving direction of the moving body toward the magnet, and the moving body. A second protrusion protruding from the other end portion of the shaft portion in the moving direction toward the magnet;
The drive coil is wound in a direction orthogonal to the moving direction of the movable body around a portion of the yoke between the first protrusion and the second protrusion.
The length dimension of the magnet in the moving direction of the moving body is shorter than the length dimension of the yoke in the moving direction of the moving body.

  According to the present invention, either the moving body or the fixed body includes a magnet having a magnetic pole surface parallel to the moving direction of the moving body, and the other of the moving body and the fixed body faces the magnetic pole surface of the magnet. And a drive coil wound in a direction orthogonal to the moving direction of the moving body. Accordingly, when power is supplied to the drive coil, a Lorentz force is generated because the direction of the excitation current flowing through the drive coil and the direction of the magnetic field of the magnet are orthogonal. Further, since the drive coil is wound around the yoke, when power is supplied to the drive coil, the drive coil and the yoke function as an electromagnetic coil (electromagnet), and electromagnetic attraction is provided between the electromagnetic coil and the magnet. Force and electromagnetic repulsive force are generated. Furthermore, since the first protrusion and the second protrusion protruding toward the magnet are provided at both ends of the yoke extending in the moving direction of the moving body, the linearly moving moving body is placed on any of these protrusions. When approaching, a magnetic attractive force is generated between the magnet and the protrusion. That is, in the positive displacement pump of the present invention, the Lorentz force, the electromagnetic attractive force or electromagnetic repulsive force generated between the electromagnetic coil and the magnet, and the magnetic force generated between the protruding portion of the yoke and the magnet. The attractive suction force can be used as the thrust of the movable body. As a result, a thrust can be obtained using these three forces, so that the movable body for changing the volume of the pump chamber can be driven efficiently.

  In the present invention, in the state where the positive displacement pump is not operated, the moving body is configured such that a magnetic attraction force between the magnet and the first protrusion or a magnetic force between the magnet and the second protrusion. It is desirable that the first position or the second position different from the first position is selectively held by a suction force. In this way, when the positive displacement pump is not operating, the moving body can be prevented from moving due to vibrations applied from the outside.

  In the present invention, the moving body includes the magnet, the fixed body includes the yoke and the drive coil, and the magnet includes a first magnetic pole surface parallel to a moving direction of the moving body, And a second magnetic pole surface facing in a direction opposite to the first magnetic pole surface, wherein the first magnetic pole surface and the second magnetic pole surface are two-pole magnetized so as to have different poles, The fixed body includes a first fixed body in which the drive coil faces the first magnetic pole surface and a second fixed body in which the drive coil faces the second magnetic pole surface. To do. In this way, since the moving body can be driven by two fixed bodies, thrust can be obtained efficiently.

  In this case, in order to efficiently generate the Lorentz force, each driving coil of each fixed body has a rectangular cross-sectional shape by a plane orthogonal to the moving direction of the moving body, and each driving coil The outer peripheral surface portion which is one long side of the cross-sectional shape is opposed to each magnetic pole surface of the magnet, and the width dimension of each magnetic pole surface in the direction orthogonal to the moving direction of the moving body is It is desirable that it is shorter than the width dimension of the said outer peripheral surface part in the direction orthogonal to a moving direction.

  In this case, in order to move the moving body linearly, a case covering the first fixed body and the second fixed body, each magnetic pole surface of the moving body, and each drive coil of each fixed body, A guide mechanism for linearly moving the movable body while maintaining a constant gap between the guide, the guide mechanism projecting from the movable body, and the first of the case It is desirable to provide a guide groove provided between the fixed body and the second fixed body.

  In the present invention, the movable body is preferably a diaphragm.

  According to the present invention, either the moving body or the fixed body includes a magnet having a magnetic pole surface parallel to the moving direction of the moving body, and the other of the moving body and the fixed body faces the magnetic pole surface of the magnet. And a drive coil wound in a direction orthogonal to the moving direction of the moving body. Accordingly, when power is supplied to the drive coil, a Lorentz force is generated because the direction of the excitation current flowing through the drive coil and the direction of the magnetic field of the magnet are orthogonal. Further, since the drive coil is wound around the yoke, when power is supplied to the drive coil, the drive coil and the yoke function as an electromagnetic coil (electromagnet), and electromagnetic attraction is provided between the electromagnetic coil and the magnet. Force and electromagnetic repulsive force are generated. Furthermore, since the first protrusion and the second protrusion protruding toward the magnet are provided at both ends of the yoke extending in the moving direction of the moving body, the linearly moving moving body is placed on any of these protrusions. When approaching, a magnetic attractive force is generated between the magnet and the protrusion. That is, in the positive displacement pump of the present invention, the Lorentz force, the electromagnetic attractive force or electromagnetic repulsive force generated between the electromagnetic coil and the magnet, and the magnetic force generated between the protruding portion of the yoke and the magnet. The attractive suction force can be used as the thrust of the movable body. As a result, a thrust can be obtained using these three forces, so that the movable body for changing the volume of the pump chamber can be driven efficiently.

1 is an external perspective view of a positive displacement pump to which the present invention is applied. It is a longitudinal cross-sectional view of the positive displacement pump of FIG. It is a disassembled perspective view of the positive displacement pump of FIG. It is a fragmentary sectional view of the periphery of the electromagnetic linear motion actuator in a state where the moving body is in the raised position. FIG. 5 is a cross-sectional view of the electromagnetic linear motion actuator taken along line AA ′ in FIG. 4. It is explanatory drawing for demonstrating drive control and operation | movement of an electromagnetic linear motion actuator. It is a fragmentary sectional view of the periphery of the electromagnetic linear motion actuator in a state where the moving body is in the lowered position. It is a time chart which shows the electric current value of the exciting current to an electromagnetic linear actuator. It is the graph which verified the relationship between the position of a moving body and thrust. It is the graph which verified the relationship between the position of a moving body in the state which considered the reaction force of the diaphragm, and thrust. It is a fragmentary sectional view around a valve chamber. It is a fragmentary sectional view around an active valve in a state where an inflow side channel is closed. It is explanatory drawing for demonstrating the force which acts on the valve body of an active valve. It is a fragmentary sectional view around an active valve in a state where an inflow side channel is opened. It is explanatory drawing for demonstrating the electromagnetic type linear motion actuator of a modification. It is explanatory drawing for demonstrating the electromagnetic type linear actuator of another modification. It is a longitudinal cross-sectional view of the positive displacement pump of the modification.

  A positive displacement pump to which the present invention is applied will be described with reference to the drawings.

(overall structure)
FIG. 1 is an external perspective view of a positive displacement pump to which the present invention is applied. FIG. 2 is a longitudinal sectional view of the positive displacement pump of FIG. The positive displacement pump 1 includes a pump unit 2 and an electromagnetic direct acting actuator 3 and an active valve 4 arranged in parallel below the pump unit 2. In the following description, the direction in which the electromagnetic linear actuator 3 and the active valve 4 are arranged is the device width direction (shown as the left-right direction in FIG. 1), and the device width direction and the direction orthogonal to the up-down direction are the device directions. The front-rear direction. The electromagnetic linear actuator 3 is disposed on the left side in the apparatus width direction, and the active valve 4 is disposed on the right side in the apparatus width direction.

  An outlet pipe 5 protruding upward is provided on the left side portion of the pump unit 2, and the upper end opening of the outlet pipe 5 is a fluid outlet 5a. An inflow pipe 6 is provided below the active valve 4, and a lower end opening of the inflow pipe 6 serves as a fluid inlet 6a. The electromagnetic linear actuator 3 and the active valve 4 are driven and controlled by a drive controller 7.

  As shown in FIG. 2, a pump chamber 8 is formed inside the pump unit 2. An inflow side channel 9 is formed between the fluid inlet 6 a and the pump chamber 8, and an active valve 4 that opens and closes the inflow side channel 9 is disposed in the inflow side channel 9. An outflow channel 10 is formed between the pump chamber 8 and the fluid outlet 5a. A check valve 11 for preventing a back flow of fluid is disposed in the outflow side channel 10.

  The bottom surface of the pump chamber 8 is defined by a diaphragm (movable body) 12, and the volume of the pump chamber 8 is changed by reciprocating the diaphragm 12 by the electromagnetic linear actuator 3. That is, the positive displacement pump 1 opens the active valve 4 to expand the volume of the pump chamber 8 to suck fluid from the fluid inlet 6a into the pump chamber 8, and closes the active valve 4 to reduce the volume of the pump chamber 8. By doing so, the fluid sucked into the pump chamber 8 is discharged from the fluid outlet 5a.

(Pumping unit)
FIG. 3 is an exploded perspective view of the positive displacement pump 1. The pump unit 2 will be described with reference to FIGS. The pump unit 2 includes an upper housing 21 and a lower housing 22 disposed below the upper housing 21.

  The upper housing 21 is made of PPS (polyphenylene sulfide) resin. The outflow pipe 5 protrudes upward from the left side portion of the upper end surface of the upper housing 21. As shown in FIG. 2, a circular first recess 211 that is recessed upward is provided on the left side of the lower end surface of the upper housing 21. A lower end opening 212 a of the first flow path 212 communicating with the outflow pipe 5 is exposed at the central portion of the ceiling surface of the first recess 211.

  The lower housing 22 is made of PPS (polyphenylene sulfide) resin. A circular upper protrusion 221 that fits into the first recess 211 of the upper housing 21 is formed on the left side of the upper end surface. A circular second recess 222 that is recessed downward is formed in the central portion of the upper protrusion 221. The upper protrusion 221 is fitted in the first recess 211, and the valve chamber 13 is formed coaxially with the outflow pipe 5 by the first recess 211 of the upper housing 21 and the second recess 222 of the lower housing 22. An O-ring 14 is disposed between the outer peripheral surface of the upper protrusion 221 and the inner peripheral surface of the first recess 211. A check valve 11 is configured in the valve chamber 13.

  A circular lower protrusion 223 is formed on the lower surface of the left portion of the lower housing 22. A circular third recess 224 that is recessed upward is provided at the center of the lower protrusion 223. The ceiling surface 224a of the third recess 224 is a tapered surface inclined upward toward the central portion, and the lower end opening 225a of the second flow path 225 communicating with the valve chamber 13 is exposed at the central portion. ing. The upper end opening 225 b of the second flow path 225 is exposed at the central portion of the circular bottom surface 13 a of the valve chamber 13. The ceiling surface 224 a and the inner peripheral surface of the third recess 224 define the ceiling surface and the inner peripheral surface of the pump chamber 8. The pump chamber 8, the second flow path 225, the valve chamber 13, the first flow path 212, and the outflow pipe 5 are formed on the same axis, and the second flow path 225, the valve chamber 13, the first flow path 212, the outflow The pipe 5 constitutes the outflow side channel 10.

  A diaphragm 12 that defines the bottom surface of the pump chamber 8 is disposed below the lower protrusion 223. The diaphragm 12 is a rubber elastic body made of EPDM (ethylene propylene diene rubber) or the like, and has a circular planar shape when viewed from above. The diaphragm 12 has a central portion and an outer peripheral edge portion formed thick, and a connecting film portion having a constant thickness that curves so as to bulge upward is provided between the central portion and the outer peripheral edge portion. A connection portion 12 a for connecting the electromagnetic linear actuator 3 is provided at a lower portion of the central portion of the diaphragm 12.

  The electromagnetic linear actuator 3 is attached to the lower housing 22 using the outer peripheral side of the lower protrusion 223. When the electromagnetic linear actuator 3 is attached, the outer peripheral edge portion of the diaphragm 12 is sandwiched between the annular lower end surface of the lower protrusion 223 and the electromagnetic linear actuator 3 and is fixed. Is done.

  A circular fourth recess 226 that is recessed upward is formed on the lower surface of the right side portion of the lower housing 22. The fourth recess 226 includes, from below, a flat large-diameter portion 226a and a small-diameter portion 226b having a smaller diameter than the large-diameter portion. The upper end portion of the active valve 4 is inserted into the fourth recess 226 via the O-ring 15.

  In a state where the active valve 4 is inserted into the fourth recess 226, a space is formed in the upper end portion 226c of the small diameter portion 226b, and there is a space between the upper end portion 226c and the pump chamber 8. A third flow path 227 for communication is formed. The right end opening of the third channel 227 is exposed on the inner peripheral side surface of the upper end portion 226c of the small diameter portion 226b, and the left end opening of the third channel 227 is the ceiling surface of the pump chamber 8 and the lower end of the second channel 225. The part is exposed.

(Electromagnetic linear actuator)
The electromagnetic linear actuator 3 will be described with reference to FIGS. 1 and 3 to 5. FIG. 4 is a partial cross-sectional view of the periphery of the electromagnetic linear actuator 3 with the moving body 33 in the raised position. FIG. 5 is a sectional view of the electromagnetic linear actuator 3 taken along the line AA ′ of FIG.

  As shown in FIG. 1, the electromagnetic linear actuator 3 has an actuator case 30 that has a rectangular parallelepiped shape as a whole. As shown in FIG. 3, the actuator case 30 includes a box-shaped upper case 31 having an opening at the lower end, and a lower case 32 attached so as to close the opening at the lower end of the upper case 31. Yes. Inside the upper case 31 and the lower case 32, a movable body 33 that can move in the vertical direction and a fixed body 34 for moving the movable body 33 are arranged. The upper end portion of the moving body 33 is fixed to the connecting portion 12a of the diaphragm 12. When the moving body 33 reciprocates in the vertical direction, the diaphragm 12 reciprocates in the vertical direction to change the volume of the pump chamber 8. The fixed body 34 includes a first fixed body 35 disposed on the left side of the moving body 33 in the apparatus width direction and a second fixed body 36 disposed on the right side.

  As shown in FIG. 3, the moving body 33 includes a rectangular parallelepiped magnet 331 that has a side surface that is parallel to the moving direction of the moving body 33. The magnet 331 is two-pole magnetized, and magnetic pole surfaces 331a and 331b magnetized to different poles on the left and right sides facing the device width direction. In the present embodiment, the magnetic pole surface 331a is magnetized to the S pole, and the magnetic pole surface 331b is magnetized to the N pole (see FIG. 6). In addition, the moving body 33 includes a magnet holder 332 that holds an outer peripheral surface portion excluding the magnetic pole surfaces 331 a and 331 b of the magnet 331.

  The magnet holder 332 includes front and rear vertical frame portions 332a that hold the front and rear side surfaces of the magnet 331 from the front and rear direction of the apparatus, an upper frame portion 332b that connects upper end portions of the front and rear vertical frame portions 332a, The lower frame part 332c which has connected the lower end part of the vertical frame part 332a is provided. The front and rear vertical frame portions 332a are provided with guide protrusions 333 and 333 that protrude in parallel with the magnetic pole surfaces 331a and 331b, respectively. Each guide protrusion 333 has a rectangular parallelepiped shape and has a predetermined length in the vertical direction. A connection part 334 with the diaphragm 12 is provided on the upper frame part 332b so as to protrude upward. The lower frame portion 332c is provided with a guide shaft 335 protruding downward.

  The first fixed body 35 and the second fixed body 36 include yokes 37 and 37 and drive coils 38 and 38 wound around the yokes 37 and 37, respectively. As shown in FIG. 5, the first fixed body 35 is arranged such that the drive coil 38 faces the magnetic pole surface 331a of the moving body 33 with a certain gap therebetween, and the second fixed body 36 is The drive coil 38 is arranged to face the magnetic pole surface 331b with a certain gap.

  As shown in FIG. 4, each of the yokes 37 and 37 includes a shaft portion 371 extending in the vertical direction, first protrusions 372 and 372 projecting inward from the upper end portion of the shaft portion 371, and the shaft portion 371. 2nd protrusion part 373 and 373 which protrudes inward from the lower end part of this is provided.

  Each drive coil 38, 38 is disposed at a portion of the yokes 37, 37 between the first protrusions 372, 372 and the second protrusions 373, 373 in a direction orthogonal to the moving direction (vertical direction) of the moving body 33. It is wound. As shown in FIG. 5, each drive coil 38, 38 has a rectangular cross-sectional shape by a plane orthogonal to the moving direction of the moving body 33, and an outer peripheral surface portion 38 a that is one long side of the cross-sectional shape. , 38a are opposed to the magnetic pole surfaces 331a, 331b of the magnet 331.

  Here, the width dimension of the moving body 33 in the front-rear direction of the magnet 331 is set to be shorter than the width dimension of the outer peripheral surface portions 38a, 38a in the front-rear direction of the apparatus. In addition, the length dimension “a” of the moving body 33 in the vertical direction of the magnet 331 is shorter than the length dimension “b” between the first protrusions 372 and 372 and the second protrusions 373 and 373 in each yoke 37 and 37. The length is set (see FIG. 4). The length dimension a of the magnet 331 is such that when the moving body 33 moves within a predetermined moving range in the vertical direction, the magnet 331 is magnetic between the first protrusions 372 and 372 and the second protrusions 373 and 373. There is a region where the attractive force does not work or the influence of the magnetic attractive force is small. Specifically, this region is a range of a substantially straight line passing through a displacement amount of 0 mm and a thrust of 0 mN in the graph shown in FIG.

  Further, as shown in FIG. 3, the lower ends of the yokes 37 and 37 are held by the lower case 32, and the upper ends of the yokes 37 and 37 are supported by a frame-shaped spacer 39. Accordingly, the drive coil 38 of the first fixed body 35 and the drive coil 38 of the second fixed body 36 are maintained at a constant interval along the moving direction of the moving body 33. Further, in the yokes 37 and 37, the ends of the first protrusions 372 and 372 and the second protrusions 373 and 373 on the moving body 33 side are closer to the moving body 33 than the outer peripheral surface portions 38 a and 38 a of the drive coils 38 and 38. The protrusions of the first protrusions 372 and 372 and the protrusions of the second protrusions 373 and 373 that are located on the side and protrude from the shafts 371 and 371 toward the moving body 33 are the same.

  The lower case 32 has a flat rectangular parallelepiped shape, and a pair of concave portions 322 and 322 serving as holding portions for the yokes 37 and 37 are formed on the upper end surface. A groove 323 extending in the longitudinal direction of the apparatus is formed between the pair of recesses 322 and 322 in the apparatus width direction, and a circular through hole 324 is formed in the central portion of the groove 323. The guide shaft 335 of the magnet holder 332 is inserted into the through hole 324. A pair of engaging protrusions 325 and 325 projecting upward are formed outside the pair of recesses 322 and 322 in the apparatus width direction.

  As shown in FIG. 3, the upper case 31 includes a rectangular upper plate 311 and four side plates 312 to 315 that extend downward from four edges of the upper plate 311. The upper plate 311 is provided with a rectangular connecting portion 316 that protrudes upward from its upper end surface. A through hole 316a is formed in the central portion of the connecting portion 316, and a stepped portion 316b extending outward is provided at the upper end portion of the through hole 316a. In the state where the electromagnetic linear actuator 3 is attached to the lower housing 22, as shown in FIG. 4, the lower protrusion 223 of the lower housing 22 is inserted inside the step 316b, and the lower protrusion 223 is inserted. The peripheral edge portion of the diaphragm 12 is sandwiched between the annular lower end surface and the annular end surface of the step portion 316b.

  Engaging recesses 317 and 317 extending in the vertical direction are formed in the two side plates 312 and 314 extending in parallel in the apparatus width direction. When the upper case 31 is put on the lower case 32, the pair of engagement protrusions 325 and 325 engage with the engagement recesses 317 and 317 of the side plates 312 and 314 to fix the upper case 31 to the lower case 32.

  The two side plates 313 and 315 extending in parallel in the apparatus front-rear direction are formed with guide grooves 318 and 318 extending upward with a certain width from the lower end edge of the central portion in the apparatus width direction. The guide grooves 318 and 318 are located at the center of the first fixed body 35 and the second fixed body 36 in the apparatus width direction. When the upper case 31 is put on the lower case 32, the front and rear guide protrusions 333 and 333 of the moving body 33 are inserted into the front and rear guide grooves 318 and 318 of the upper case 31, as shown in FIG. The Here, the guide protrusions 333 and 333 and the guide grooves 318 and 318 guide the moving body 33 in the vertical direction with the gap between the magnetic pole surfaces 331a and 331b and the drive coils 38 and 38 maintained constant. The moving mechanism 33 is arranged on the axis of the pump chamber 8, the second flow path 225, the valve chamber 13, the first flow path 212, and the outflow pipe 5 by the guide mechanisms 40, 40. Will be guided.

  Upper end edges 318 a and 318 a of the guide grooves 318 and 318 define an upper limit of the moving range of the moving body 33. That is, when the moving body 33 tries to move above the raised position (first position) 33A shown in FIG. 4, the guide protrusions 333 and 333 come into contact with the upper edges 318a and 318a of the guide grooves 318 and 318, respectively. To prevent the movement. At the raised position 33A, the upper end surface 331c of the magnet 331 of the moving body 33 is located below the upper end surfaces of the first protrusions 372 and 372 of the yokes 37 and 37. In the state where the moving body 33 is located at the ascending position 33A, the diaphragm 12 sets the volume of the pump chamber 8 to the minimum first volume. The movable body 33 is configured to be positioned at the raised position 33 </ b> A by the guide protrusions 333 and 333 of the movable body 33 coming into contact with the upper end edges 318 a and 318 a of the guide grooves 318 and 318 of the upper case 31. You can also That is, the upper end edges 318a and 318a may be provided with a function as a moving body positioning unit that defines the upper limit of the moving range of the moving body 33.

  The upper end surfaces 32 a and 32 a of the lower case 32 define the lower limit of the moving range of the moving body 33. That is, when the moving body 33 tries to move downward from the lowered position (second position) 33B (see FIG. 7), the guide protrusions 333 and 333 come into contact with the upper end surfaces 32a and 32a of the lower case 32. , Stop that movement. In the lowered position 33 </ b> B, the lower end surface 331 d of the magnet 331 of the moving body 33 is positioned above the lower end surfaces of the second protrusions 373 and 373 of the yokes 37 and 37. Further, in the state where the moving body 33 is located at the lowered position 33B, the diaphragm 12 expands the volume of the pump chamber 8 to the maximum second volume. Note that the movable body 33 may be positioned at the lowered position 33B by the guide protrusions 333 and 333 of the movable body 33 coming into contact with the upper end surfaces 32a and 32a of the lower case 32. That is, the upper end surfaces 32a and 32a may be paired with the upper end edges 318a and 318a described above, and may have a function as a moving body positioning unit that defines the lower limit of the moving range of the moving body 33.

  Further, while the moving body 33 moves between the raised position 33A and the lowered position 33B, the state where the guide shaft 335 extending downward from the magnet holder 332 is inserted into the through hole 324 is maintained. Thereby, the moving body 33 moves linearly in a state in which the posture is maintained without being inclined with respect to the moving direction.

(Drive control and operation of electromagnetic linear actuator)
The drive control and operation of the electromagnetic linear actuator 3 will be described with reference to FIGS. 2 and 6 to 10. FIG. 6 is an explanatory diagram for explaining the drive control and operation of the electromagnetic linear actuator 3 and shows a state in which the moving body 33 is in the raised position 33A. FIG. 7 is a partial cross-sectional view of the periphery of the electromagnetic linear actuator with the moving body 33 in the lowered position 33B. FIG. 8 is a time chart showing the current value of the excitation current applied to the electromagnetic linear actuator 3, and shows the current value of the excitation current while the moving body 33 is reciprocated between the rising position 33A and the lowering position 33B. Show. FIG. 9 is a graph in which the relationship between the position of the moving body 33 and the thrust is verified by changing the current value of the excitation current supplied to the drive coils 38 and 38. FIG. 9 also shows a graph showing the relationship between the position of the moving body 33 and the reaction force acting on the moving body 33 from the diaphragm 12. FIG. 10 is a graph in which the relationship between the position of the moving body 33 and the thrust is verified by changing the current value of the excitation current supplied to the drive coils 38 and 38 in a state where the reaction force of the diaphragm 12 is taken into consideration.

  9 and 10, the moving body 33 and the diaphragm 12 are in the positions shown in FIG. 2, and the center of the magnet 331 and the drive coil 38 in the moving direction (vertical direction) of the moving body 33 are as follows. The center of 38 coincides. The movable body 33 is located at the raised position 33A shown in FIG. 6 at the position where the displacement is 0.6 mm, and the movable body 33 is located at the lowered position 33B shown in FIG. 7 at the position where the displacement is −0.6 mm. . Further, in FIG. 9, a graph rising to the right passing through a thrust of 0 mN and a displacement of 0 mm measured the thrust at each position (displacement) of the moving body 33 in a state where power is not supplied to the drive coils 38 and 38. Is. In FIG. 9, a downward-going graph passing through a thrust of 0 mN and a displacement of 0 mm indicates that the moving body 33 is moved from the diaphragm 12 to the moving body 33 at each position (displacement) of the moving body 33 in a state where power is not supplied to the drive coils 38 and 38. This is a measurement of the reaction force acting on. The sign of-given to the current value indicates the direction in which the excitation current flows, and means that the excitation current flows in the first direction D1 shown in FIG. The sign of + means that an exciting current is passed in the second direction D2 opposite to the direction shown in FIG. Further, the sign given to the thrust indicates the direction in which the thrust works, the + sign indicates the upper side, and the-sign indicates the lower side.

  First, in a state where power is not supplied to the drive coils 38, 38, the moving body 33 has a magnetic attractive force F 1 between the magnet 331 and the first protrusions 372, 372 of the yokes 37, 37 and the diaphragm 12. Due to the action of the reaction force R1, it stops at the raised position 33A and is held at the raised position 33A as shown in FIG.

  In this example, when the moving body 33 is in the raised position 33A, the magnetic attraction between the magnet 331 and the first protrusions 372 and 372 of the yokes 37 and 37 as shown in the graph of the current value 0 mA in FIG. A thrust of about 200 mN is generated upward by the force F1. On the other hand, when the moving body 33 is in the raised position 33A, as shown in FIG. 6, the diaphragm 12 reduces the volume of the pump chamber 8 to the minimum first volume, and its central portion is smaller than the outer peripheral edge portion. The state is displaced upward. Therefore, the diaphragm 12 generates a reaction force R1 of about 100 mN downward. As a result, as shown in FIG. 10, the moving body 33 is directed upward by subtracting the reaction force R1 of the diaphragm 12 from the magnetic attractive force F1 between the magnet 331 and the first protrusions 372 and 372 of the yokes 37 and 37. Is stopped at the ascending position 33A by the force (about 100 mN).

  Next, when performing the forward movement process (first movement process) in which the moving body 33 is moved from the raised position 33A to the lowered position 33B, power is supplied to the drive coils 38, 38. In this example, as shown in FIG. 6, in the magnet 331 of the moving body 33, the left magnetic pole surface 331a is magnetized to the S pole, and the right magnetic pole surface 331b is magnetized to the N pole. Therefore, the excitation current flowing through the winding portion constituting the outer peripheral surface portion 38a facing the magnetic pole surface 331a from the process start time t0 is applied to the left driving coil 38 facing the magnetic pole surface 331a from the front of the device. An exciting current in the first direction D1 flowing backward is passed. Further, in the right drive coil 38 facing the right magnetic pole surface 331b, the excitation current flowing through the winding portion facing the magnetic pole surface 331b from the process start time t0 in the first direction D1 from the front of the apparatus toward the rear of the apparatus. Exciting current is applied.

  Here, since the magnet 331 of the moving body 33 is located on the outer peripheral side of the drive coils 38, 38, the direction of the excitation current flowing through the drive coils 38, 38 by feeding is orthogonal to the direction of the magnetic field by the magnet 331. As a result, when power is supplied to the drive coils 38, the Lorentz force acting between the drive coils 38, 38 and the magnetic field of the magnet 331 moves the moving body 33 downward according to Fleming's left-hand rule. Work as force F2.

  Further, the drive coils 38 and 38 and the yokes 37 and 37 function as electromagnetic coils (electromagnets) by supplying power to the drive coils 38 and 38 according to Ampere's right-handed screw law. That is, the first fixed body 35 disposed on the left side of the moving body 33 functions as an electromagnetic coil having the S pole on the upper side and the N pole on the lower side. The second fixed body 36 disposed on the right side of the moving body 33 functions as an electromagnetic coil having an N pole on the upper side and an S pole on the lower side. As a result, an electromagnetic repulsive force is generated on the upper side and an electromagnetic attractive force is generated on the lower side between the magnet 331 of the moving body 33 and the first fixed body 35 and the second fixed body 36. . The resultant force F3 of the electromagnetic repulsive force and the attraction force is a thrust for moving the moving body 33 downward together with the force F2 that moves the moving body 33 downward.

  The thrust generated by the force F2 for moving the moving body 33 downward and the resultant force F3 of the electromagnetic repulsive force and the attractive force appear in FIG. 9 as the difference in thrust between the current value graph and the current value graph. In this example, when an excitation current of -10 mA is supplied to the drive coils 38, 38, a downward thrust of a little less than 100 mN appears as a difference between the graph of the current value of 0 mA and the graph of the current value of -10 mA. can get. Similarly, when an excitation current of −30 mA is supplied to the drive coils 38, 38, a downward thrust exceeding 200 mN is obtained. When an excitation current of −50 mA is supplied to the drive coils 38, 38, a downward thrust exceeding 300 mN is obtained.

  Here, in this example, the moving body 33 is held at the raised position 33A by an upward force of about 100 mN at the raised position 33A. Therefore, in this example, in the first section P1 in which the moving body 33 moves away from the ascending position 33A as shown in FIG. 10, the first exciting current I1 of −30 mA is supplied to the drive coils 38 and 38 as shown in FIG. Generating downward thrust exceeding 100 mN. Thereby, the moving body 33 moves away from the ascending position 33A and moves downward.

  Next, when the moving body 33 moves away from the ascending position 33A, the magnet 331 moves away from the first protrusions 372 and 372 of the yokes 37 and 37. Therefore, as shown in the graph of the current value 0 mA in FIG. The magnetic attractive force F1 that has been acting on decreases in inverse proportion to the square of the distance. When the moving body 33 has a displacement of 0.2 mm to −0.2 mm, the magnet 331 and the first protrusions 372 and 372 of the yokes 37 and 37 are almost affected by the magnetic attractive force F1. That is, the magnetic attractive force F1 is substantially zero.

  Further, when the moving body 33 is at a position where the displacement amount is 0 mm, the diaphragm 12 is not displaced in the vertical direction as shown in FIG. Therefore, as shown in the graph of the reaction force R1 from the diaphragm 12 in FIG. 9 (elastic force possessed by the diaphragm 12), the reaction force R1 does not act from the diaphragm 12 to the moving body 33. Therefore, in the second section P2 where the moving body 33 passes in the vicinity of the position where the displacement amount is 0 mm, the moving body 33 can be lowered only by applying a slight thrust to the moving body 33.

  Therefore, in this example, as shown in FIGS. 8 and 10, in the second section P2 in which the moving body 33 passes in the vicinity of the position where the displacement amount is 0 mm, the drive coils 38 and 38 are supplied to the drive coils 38 and 38 more than the first excitation current I1. By supplying a small −10 mA second exciting current I2, a downward thrust of slightly less than 100 mN is generated, and thereby the moving body 33 is lowered. In FIG. 4, the vertical dimension “a” of the magnet 331 is set to be shorter than the dimension “b” between the first protrusions 372 and 372 and the second protrusions 373 and 373. It is possible to lengthen the second section P2 in which the magnetic attractive force acting between the first protrusions 372 and 372 and the second protrusions 373 and 373 is substantially zero.

  Thereafter, when the moving body 33 approaches the lowered position 33B, the magnet 331 approaches the second protrusions 373 and 373, so that the magnetic attractive force F4 between the magnet 331 and the second protrusions 373 and 373 works. The suction force F4 increases in inverse proportion to the square of the distance. Moreover, since the suction force F4 is a force that works downward, the suction force F4 is a thrust that moves the moving body 33 downward. Here, when the moving body 33 approaches the lowered position 33B, the center portion of the diaphragm 12 is displaced downward with respect to the outer peripheral edge portion as shown in FIG. As shown in the graph of the force R1, the reaction force R1 from the diaphragm 12 to the moving body 33 works upward. However, as shown in FIG. 9, the reaction force R1 acting on the moving body 33 from the diaphragm 12 is smaller than the magnetic attractive force F4 between the magnet 331 and the second protrusions 373 and 373. The moving body 33 is lowered to the lowered position 33B by the suction force F4.

  That is, in this example, in the third section P3 in which the moving body 33 approaches the lowered position 33B, the moving body 33 is lowered only by the suction force F4. Therefore, in this example, as shown in FIGS. 8 and 10, in the third section P3 in which the moving body 33 approaches the lowered position 33B, the third excitation current I3 supplied to the drive coils 38 and 38 is set to zero, That is, the power supply to the drive coils 38, 38 is stopped, and the moving body 33 is lowered only by the attractive force F4.

  Thereafter, when the moving body 33 reaches the lowered position 33B shown in FIG. 7, the magnetic body 331 and the magnetic attraction force F4 between the second protrusions 373 and 373 of the yokes 37 and 37 and the moving body 33 move downward. The movable body 33 stops because the reaction force R1 from the displaced diaphragm 12 is balanced.

  In the lowered position 33B, the diaphragm 12 expands the volume of the pump chamber 8 to the maximum second volume. That is, at the lowered position 33B, when the positive displacement pump 1 is operated and the electromagnetic linear actuator 3 is operating, power is not supplied to the drive coils 38, 38. Then, the magnetic attractive force F4 and the reaction force R1 from the diaphragm 12 act between the second protrusions 373 and 373 of the yokes 37 and 37, and the moving body 33 stops. Further, in this example, when the positive displacement pump 1 is not operating, power is not supplied to the drive coils 38, 38, so that the moving body 33 has the second protrusion of the magnet 331 and the yokes 37, 37. The moving body 33 is held at the lowered position 33B by the action of the magnetic attractive force F4 with the parts 373 and 373 and the reaction force R1 of the diaphragm 12.

  Next, in the backward movement process (second movement process) in which the moving body 33 is moved from the lowered position 33B to the raised position 33A, the same force is opposite to that during the movement of the movable body 33 from the raised position 33A to the lowered position 33B. Work in the direction. Therefore, as shown in FIG. 8, the first to third excitation currents I1 to I3 in the second direction D2 opposite to the forward movement process of moving the moving body 33 from the raised position 33A to the lowered position 33B It supplies to the drive coils 38 and 38 in this order from t0. As a result, the moving body 33 has a Lorentz force generated by power feeding, an electromagnetic attractive force, and a resultant force of the electromagnetic attractive force, and a magnetic attractive force between the magnet 331 and the first protrusions 372 and 372. Ascending with F1 as a thrust, it reaches the ascending position 33A. In this example, since the forward movement process and the backward movement process are continuously performed, the process end time t1 of the forward movement process when the moving body 33 reaches the lowered position 33B is the process start time t0 of the next backward movement process. It has become.

  Thereafter, when the moving body 33 is positioned at the raised position 33A, the magnetic attractive force F1 between the magnet 331 and the first protrusions 372 and 372 of the yokes 37 and 37, and the diaphragm displaced upward by the moving body 33 The reaction force R1 from 12 balances and the moving body 33 stops. Further, in this example, when the positive displacement pump 1 is not operating, power is not supplied to the drive coils 38, 38, and the magnet 331 of the moving body 33 and each yoke 37, Since the magnetic attractive force F1 is acting between the 37 first protrusions 372 and 372, the moving body 33 is held at the raised position 33A.

  Here, as shown in FIG. 10, in this example, in order to move the moving body 33 reliably, the first section P1 is a period until the moving body 33 moves from the raised position 33A to the position where the displacement amount is 0.2 mm. A first exciting current I1 of −30 mA is supplied. The second excitation current I2 of −10 mA is supplied as the second section P2 until the moving body 33 moves from the position of the displacement amount 0.2 mm to the position of the displacement amount −0.4 mm. Power supply is stopped as the third section P3 until the moving body 33 passes the displacement amount −0.4 mm and reaches the lowered position 33B.

  On the other hand, although description in FIG. 10 is omitted, when the moving body 33 is moved from the lowered position 33B to the raised position 33A, the moving body 33 moves from the lowered position 33B to the position where the displacement is −0.2 mm. The first excitation current I1 of 30 mA is supplied as the first section P1, and the 10 mA of 10 mA is set as the second section P2 until the moving body 33 moves from the position of the displacement amount −0.2 mm to the position of the displacement amount 0.4 mm. The two excitation currents I2 are supplied, and the power supply is stopped as the third section P3 until the moving body 33 passes the displacement amount 0.4 mm and reaches the rising position 33A.

  In this example, when moving the moving body 33 from the raised position 33A to the lowered position 33B, the first section P1 is -30 mA until the moving body 33 moves from the raised position 33A to a position with a displacement of 0.4 mm. The second excitation current I2 of -10 mA is supplied and moved until the moving body 33 moves from the position of the displacement amount 0.4 mm to the position of the displacement amount 0 mm as the second section P2. The power supply may be stopped after the body 33 has passed the displacement of 0 mm. Even in this case, since a thrust force for moving the moving body 33 downward can be obtained, the moving body 33 can be moved from the raised position 33A to the lowered position 33B. In this example, the third excitation current I3 is set to zero. However, in order to move the moving body 33 with certainty, a third excitation current I3 smaller than the second excitation current I2 is used as the third excitation current I3 as a drive coil. You may supply to 38,38. For example, the third excitation current I3 may be a current close to zero.

(Check valve)
FIG. 11 is a partial cross-sectional view around the valve chamber 13. As shown in FIG. 11, the check valve 11 includes a valve seat 111 in which an upper end opening 225 b of the second flow path 225 is formed, and the upper end opening by contacting the valve seat 111 from the downstream side in the fluid flow direction. The valve body 112 blocking the 225b, and a biasing member that is inserted between the valve body 112 and the circular ceiling surface 13b of the valve chamber 13 and biases the valve body 112 to the valve seat 111 with a predetermined biasing force. It has. In this embodiment, the urging member is a compression coil spring 113, and the valve seat 111 is a circular bottom surface 13 a of the valve chamber 13.

  The valve body 112 is made of a rubber elastic material such as EPDM (ethylene propylene diene rubber), and has a circular flat plate-shaped closing portion 112a facing the valve seat 111, and downward from the lower surface of the closing portion 112a. And an annular protrusion 112b that protrudes. The annular protrusion 112 b is formed coaxially with the closing portion 112 a and abuts around the upper end opening 225 b of the second flow path 225 in the valve seat 111. The annular protrusion 112b is formed so as to be inclined downward from the outer peripheral edge of the lower surface of the closing portion 112a toward the outside, and is tapered so that the thickness dimension decreases as the distance from the closing portion 112a increases. Yes.

  Further, the valve body 112 includes a positioning portion 112c for positioning the contact position of the compression coil spring 113 on the upper surface of the closing portion 112a located on the side opposite to the valve seat 111. The positioning portion 112c is a cylindrical protrusion having an outer diameter corresponding to the inner diameter of the lower end opening 113a of the compression coil spring 113, and is formed coaxially with the annular protrusion 112b.

  The compression coil spring 113 has an inner diameter that increases upward. The inner diameter of the lower end opening 113a is larger than the opening diameter of the upper end opening 225b of the second flow path 225, and is set to a size that allows the positioning portion 112c to be inserted. When the check valve 11 is disposed in the valve chamber 13 with the lower end opening 113a of the compression coil spring 113 inserted into the positioning portion 112c, the upper end of the compression coil spring 113 has the second end of the circular ceiling surface 13b of the valve chamber 13. Abutting around the lower end opening 212a of one channel 212, the circular end of the lower end abuts on the upper surface of the closing portion 112a, and is compressed. As a result, the compression coil spring 113 biases the valve body 112 toward the valve seat 111. Note that the compression coil spring 113 is preferably disposed so that the circular end at the lower end is in contact with or near the position corresponding to the annular protrusion 112b on the upper surface of the closing portion 112a.

  The check valve 11 has a predetermined pressure equal to or higher than a predetermined urging force by the compression coil spring 113 in the outflow side passage 10 when the volume of the pump chamber 8 is reduced by the diaphragm 12 and the pump chamber 8 becomes high pressure. Is applied in the outflow direction, the upper end opening 225b of the second flow path 225 is opened, and the outflow side flow path 10 is opened. When pressure is applied to the outflow side channel 10 in the direction opposite to the outflow direction, the upper end opening 225b of the second channel 225 is closed and the outflow side channel 10 is closed.

(Active valve)
Next, the active valve 4 will be described in detail with reference to FIG. 2, FIG. 3, and FIG. FIG. 12 is a partial cross-sectional view of the periphery of the active valve 4 in a state where the inflow channel 9 is closed. As shown in FIG. 3, the active valve 4 includes a cylindrical body 41, an orifice component 42 extending coaxially upward from the body 41, and an inflow pipe extending coaxially downward from the body 41. 6 is provided.

  The orifice constituting part 42 has a smaller diameter than the body part 41, and the inflow pipe 6 has a smaller diameter than the orifice constituting part 42. The inflow pipe 6 also serves as the inflow pipe 6 of the positive displacement pump 1, and the downstream end is a fluid inlet 6a. As shown in FIG. 2, in the active valve 4, the orifice component 42 is inserted into the small diameter portion 226b of the fourth recess 226 of the lower housing 22, and the upper end portion of the body portion 41 is inserted into the large diameter portion 226a. And attached to the lower housing 22.

  As shown in FIG. 12, the orifice component 42 includes a columnar portion 421 and an annular flange portion 422 formed on the outer peripheral side of the lower end of the columnar portion 421. The cylindrical portion 421 is formed with an orifice 423 penetrating in the vertical direction along the central axis. A lower end opening 423 a of the orifice 423 is exposed at the lower end surface of the cylindrical portion 421. In addition, an annular recess 424 is formed around the lower end opening 423a of the orifice 423 on the lower end surface of the columnar portion 421, whereby the peripheral edge of the lower end opening 423a of the orifice 423 is an annular protrusion. . The annular protrusion serves as a valve seat 44 of the valve body 43 that opens and closes the lower end opening 423a of the orifice 423.

  The body portion 41 includes a fluid flow path 45 that allows the inflow pipe 6 and the orifice 423 to communicate with each other. The fluid channel 45 is provided coaxially with the orifice 423 and the inflow pipe 6. When the active valve 4 is fixed to the lower housing 22, the inflow side flow path 9 from the pump chamber 8 to the fluid inlet 6a is constituted by the third flow path 227, the upper end portion 226c of the fourth recess 226 and the active valve 4. Is done. A valve element 43 is inserted into the fluid flow path 45 so as to be reciprocally movable in the axial direction. The valve body 43 opens and closes the inflow channel 9 by opening and closing a lower end opening 423a on the fluid channel 45 side of the orifice 423.

  The valve body 43 has a cylindrical shape. The valve element 43 includes a stainless steel pipe 431, three circular magnets 432 arranged in the vertical direction inside the pipe 431, and three disc-shaped magnets arranged between adjacent magnets 432, respectively. The plate 433, two disk-shaped magnetic plates 434 arranged at the upper end and the lower end, a stainless steel lid plate 435 arranged on the upper magnetic plate 434, and the lower magnetic plate 434, respectively. A stainless steel bottom plate 436 is provided. In addition, the thing made from resin can also be used as the pipe 431, the cover board 435, and the baseplate 436. FIG. A circular rubber sheet 437 is attached to the upper surface of the cover plate 435 by a method such as adhesion. Here, the adjacent magnets 432 have the same poles facing the other magnet. More specifically, the upper end magnet 432 is arranged so that the upper side is the S pole and the lower side is the N pole, and the magnet 432 adjacently arranged below the upper side is the N pole and the lower side is the S pole. Further, the magnet 432 arranged below is arranged so that the upper part is an S pole and the lower part is an N pole, and the lower end magnet 432 is an N pole on the upper side and an S pole on the lower side. It is arranged to become. As a result, in the valve body 43, the magnetic lines of force are concentrated at the location where the magnetic plate 433 is located.

  The fluid channel 45 is formed inside a coil bobbin 47 around which a drive coil 46 for driving the valve body 43 is wound. A cylindrical yoke 48 is disposed on the outer peripheral side of the coil bobbin 47.

  The coil bobbin 47 is made of resin, and an annular engagement recess 471 for attaching the orifice component 42 is formed at the upper end portion of the coil bobbin 47. The flange portion 422 of the orifice constituting portion 42 is inserted into and fixed to the engaging recess 471 through the rubber packing 49. An annular holding plate 50 is fitted from above on the outer peripheral side of the columnar portion 421 of the orifice component 42, and the holding plate 50 is fixed to the upper end surface of the coil bobbin 47 and the upper end surface of the yoke 48. The orifice component 42 is fixed to the coil bobbin 47 and the yoke 48. The holding plate 50 is made of a magnetic material. The presser plate 50 is formed of a magnetic material, so that the presser plate 50 can generate a magnetic attractive force with the magnet 432 mounted on the valve body 43. .

  In addition, the coil bobbin 47 includes a cylindrical body part 472 extending in the vertical direction and six flange parts 473 that increase in diameter on the outer peripheral surface of the cylindrical body part 472. The five spaces surrounded by the cylindrical body portion 472 and the six flange portions 473 of the coil bobbin 47 are five winding portions around which the drive coil 46 is wound.

  The five drive coils 46 wound around the coil bobbin 47 have the winding directions of adjacent drive coils 46 reversed in order to reverse the direction of the excitation current. Further, the five drive coils 46 are electrically connected in series, for example. Alternatively, a configuration is adopted in which three drive coils 46 located on the inner side in the axial direction are electrically connected in parallel, and the drive coils 46 on both sides in the axial direction are electrically connected in series to those connected portions. You can also In this example, the vertical dimension of the upper and lower drive coils 46 is ½ of the vertical dimension of the three drive coils 46 positioned therebetween. In the valve body 43, the vertical dimension of the upper and lower magnets 432 is ½ of the vertical dimension of the two magnets 432 therebetween. As a result, when the valve body 43 is in contact with the valve seat 44 and the lower end opening 423a of the orifice 423 is closed, the magnetic plate 433 and the magnetic plate 434 are both positioned at the center of the drive coil 46 in the vertical direction. positioned.

  Here, the outer diameter dimension of the valve body 43 is slightly smaller than the inner diameter dimension of the cylindrical body portion 472 of the coil bobbin 47, and the valve body 43 is inserted into the space inside the cylindrical body portion 472 of the coil bobbin 47. In the state, the fluid flows between the outer peripheral side surface of the valve body 43 and the inner peripheral surface of the cylindrical body portion 472 of the coil bobbin 47.

(Active valve operation)
The operation of the active valve 4 will be described with reference to FIGS. FIG. 13 is an explanatory diagram for explaining the force acting on the valve body 43 of the active valve 4. FIG. 14 is a partial cross-sectional view of the periphery of the active valve 4 in a state where the inflow side passage 9 is open. The active valve 4 is driven and controlled by the power supply to the drive coil 46 controlled by the drive controller 7.

  As shown in FIG. 13, the valve body 43 is held in the closed position 43 </ b> A by the magnetic attractive force F <b> 5 between the magnet 432 of the valve body 43 and the presser plate 50 in a state where power is not supplied to the drive coil 46. Has been. In the closed position 43A, the valve body 43 has moved to the upper end of the fluid flow path 45 inside the coil bobbin 47, the rubber sheet 437 on the upper end surface of the valve body 43 abuts the valve seat 44, and the lower end opening of the orifice 423 is opened. 423a is blocked. Thereby, the inflow side flow path 9 will be in a closed state. Further, the magnetic plate 433 and the magnetic plate 434 of the valve body 43 are both positioned at the center position of the drive coil 46 in the vertical direction.

  Here, the valve body 43 is located upstream of the valve seat 44 in which the lower end opening 423 a of the orifice 423 is provided in the fluid flow direction, and is a fluid flow path 45 formed coaxially with the orifice 423. It is comprised so that it may move in the distribution direction of the fluid in the inside. For this reason, the fluid pressure (back pressure) of the fluid flowing into the active valve 4 from the fluid inlet 6a exerts the force F6 in the direction of moving the valve body 43 toward the closed position 43A.

  Next, when the inflow channel 9 is opened, power is supplied to the drive coil 46. In the active valve 4, the drive coil 46 wound in a cylindrical shape is disposed on the outer peripheral side of the magnet 432, so that the direction of the excitation current flowing through the drive coil 46 by feeding is orthogonal to the direction of the magnetic field by the magnet 432. As a result, as shown in FIG. 14, when power is supplied to the drive coil 46, the Lorentz force acting between the magnetic flux of the magnet 432 and the drive coil 46 causes the valve element 43 to move downward from the closed position 43A. Work as F7. Here, at the start of power supply to the drive coil 46, the magnetic plate 433 and the magnetic plate 434 of the valve body 43 are both positioned at the center position of the drive coil 46 in the vertical direction and are linked to the drive coil. Since the magnetic field is efficiently formed, a large thrust is generated as the force F7. Therefore, the valve body 43 resists the magnetic attraction force F5 between the holding plate 50 and the force F6 caused by the fluid pressure of the fluid flowing into the active valve 4 from the fluid inlet 6a. To the lower open position 43B.

  When the valve body 43 moves to the open position 43B, the valve body 43 is separated from the valve seat 44 to the upstream side in the fluid flow direction, and the rubber sheet 437 is separated from the lower end opening 423a of the orifice 423. Thereby, the inflow side flow path 9 will be in an open state. In the open position 43 </ b> B, the valve body 43 reaches the open position where the lower end of the valve body 43 abuts on the projecting portion 474 formed inside the coil bobbin 47, or balances and stops without abutment. In the open position 43B, the fluid that flows in from the fluid inlet 6a through the inflow pipe 6 (fluid passage 45) flows between the outer peripheral surface of the valve body 43 and the cylindrical body 472 of the coil bobbin 47, and passes through the lower end opening 423a. Through the orifice 423 and toward the pump chamber 8.

  Further, when the inflow side channel 9 is closed, the power supply to the drive coil 46 is stopped. When the power supply to the drive coil 46 is stopped, the force F6 caused by the magnetic attraction force F5 between the holding plate 50 and the fluid pressure of the fluid flowing into the active valve 4 from the fluid inlet 6a shown in FIG. Thus, the valve body 43 moves to the closed position 43A, the valve body 43 comes into contact with the valve seat 44, and returns to the state where the upper end rubber sheet 437 closes the lower end opening 423a of the orifice 423. Accordingly, the inflow channel 9 is closed.

  When the inflow channel 9 is closed, an excitation current in the opposite direction to the case where the valve body 43 is moved from the closed position to the open position may be supplied to the drive coil 46. In this way, the valve body 43 has a Lorentz force generated between the magnet 432 of the valve body 43 and the drive coil 46, a magnetic attractive force F5 between the valve body 43 and the holding plate 50, and a fluid inlet. It moves upward by a force F6 caused by the fluid pressure of the fluid flowing into the active valve 4 from 6a. After the valve body 43 reaches the closed position, if the power supply to the drive coil 46 is stopped, the valve body 43 is held at the closed position 43A.

(Operation of positive displacement pump)
Next, the operation of the positive displacement pump 1 will be described. The electromagnetic linear actuator 3 and the active valve 4 of the positive displacement pump 1 are driven and controlled in synchronization by the drive controller 7.

  In a state where power is not supplied to the drive coil 38 of the electromagnetic linear actuator 3 and the drive coil 46 of the active valve 4, the valve body 43 of the active valve 4 is held at the closed position 43A as shown in FIG. The active valve 4 closes the inflow side flow path 9. Further, as shown in FIG. 4, the moving body 33 of the electromagnetic linear actuator 3 is held at the raised position 33A, and the diaphragm 12 sets the volume of the pump chamber 8 to the minimum first volume. The check valve 11 closes the outflow side flow path 10 by closing the upper end opening 225b of the second flow path 225 by the urging force of the compression coil spring 113.

  When the fluid is sucked into the pump chamber 8, the valve element 43 is driven from the closed position 43 </ b> A to the open position 43 </ b> B by supplying power to the drive coil 46 of the active valve 4, and the inflow side flow path 9 is opened. It is said. That is, the active valve 4 is in the state shown in FIG. In parallel with this, power is supplied to the drive coils 38 of the electromagnetic linear actuator 3. In other words, the exciting current in the first direction D1 is supplied to the drive coils 38, 38, whereby the moving body 33 is driven from the raised position 33A to the lowered position 33B. As a result, as shown in FIG. 7, the volume of the pump chamber 8 is expanded to the maximum second volume.

  When the moving body 33 is lowered and the diaphragm 12 is displaced downward, a negative pressure is generated in the pump chamber 8, so that the fluid is sucked into the pump chamber 8. In a state where negative pressure is generated in the pump chamber 8, the check valve 11 closes the upper end opening 225 b of the second flow path 225 and closes the outflow side flow path 10.

  Next, when the fluid is discharged from the pump chamber 8, the power supply to the drive coil 46 of the active valve 4 is stopped. As a result, as shown in FIG. 13, the valve body 43 rises from the open position 43B to the closed position 43A, and the inflow side flow path 9 is closed. In parallel with this, power is supplied to the drive coils 38 of the electromagnetic linear actuator 3. That is, the exciting current in the second direction D2 opposite to that during the suction of the fluid is supplied to the drive coils 38, 38, and the moving body 33 is driven from the lowered position 33B to the raised position 33A. As a result, as shown in FIGS. 4 and 6, the volume of the pump chamber 8 is reduced to the minimum first volume.

  Here, when the volume of the pump chamber 8 is reduced, the pressure in the pump chamber 8 becomes high. Therefore, in the outflow side channel 10, a force greater than a predetermined pressure corresponding to the urging force of the valve body 112 by the compression coil spring 113 is in the outflow direction. It takes. As a result, the fluid moves the valve body 112 in the outflow direction, flows out from the upper end opening 225b of the second flow path 225, and is discharged from the fluid outlet 5a.

  Thereafter, when the positive displacement pump 1 enters a standby state, the valve body 43 of the active valve 4 is held at the closed position 43A, and the active valve 4 closes the inflow side flow path 9. The moving body 33 of the electromagnetic linear actuator 3 is held at the raised position 33A, and the diaphragm 12 sets the volume of the pump chamber 8 to the first volume. The check valve 11 closes the outflow side flow path 10 by closing the upper end opening 225 b of the second flow path 225 by the urging force of the compression coil spring 113.

(Function and effect)
According to this example, the fixed body 34 of the electromagnetic linear actuator 3 is opposed to the magnetic pole surfaces 331 a and 331 b of the magnet 331 parallel to the moving direction of the moving body 33, and in a direction orthogonal to the moving direction of the moving body 33. There are provided drive coils 38 and 38 which are wound around. Accordingly, when the electromagnetic direct acting actuator 3 is excited by supplying power to the drive coils 38, 38, the direction of the excitation current flowing through the drive coils 38, 38 and the direction of the magnetic field of the magnet 331 are orthogonal, and the Lorentz force Will occur. Further, since the drive coils 38, 38 are wound around the yokes 37, 37, when the power is supplied to the drive coils 38, 38, the drive coils 38, 38 and the yokes 37, 37 function as electromagnetic coils (electromagnets). In addition, an electromagnetic attractive force and an electromagnetic repulsive force are generated between the electromagnetic coil and the magnet 331. In addition, since the first protrusions 372 and 372 and the second protrusions 373 and 373 are provided at both ends of the yokes 37 and 37 extending in the moving direction of the moving body 33, the moving body 33 that moves linearly is the first one. When approaching one of the first protrusions 372 and 372 and the second protrusions 373 and 373, a magnetic attractive force is generated between the magnet 331 and the first protrusions 372 and 372 and the second protrusions 373 and 373. To do. That is, in the positive displacement pump 1, the Lorentz force, the electromagnetic attractive force, the electromagnetic repulsive force, and the magnetic attractive force can be used as the thrust of the diaphragm 12. As a result, a thrust can be obtained by using these three forces. Therefore, according to the positive displacement pump 1, the movable body for changing the volume of the pump chamber 8 can be driven efficiently. Therefore, the excitation current supplied to the drive coils 38 can be suppressed.

  Further, according to the present example, the thrust of the moving body 33 acts between the magnet of the moving body 33 and the first protrusions 372 and 372 or the second protrusions 373 and 373 of the yokes 37 and 37 of the fixed body 34. Since the magnetic attraction force is used, after the moving body 33 moves away from the ascending position 33A or the descending position 33B, even if the current value of the excitation current supplied to the drive coils 38, 38 is reduced, the moving body 33 can be moved. Therefore, the power consumption of the positive displacement pump 1 is compared with the case where an excitation current having a constant magnitude is continuously supplied to the drive coils 38 and 38 while the movable body 33 is moved between the raised position 33A and the lowered position 33B. Can be reduced. Further, in this example, since the third excitation current I3 is set to zero, further power saving can be achieved.

  Further, in this example, when the positive displacement pump 1 is not operating, the power supply to the drive coils 38, 38 is stopped, so the magnet 331 and the first protrusions 372, 372 or the second protrusion 373, The moving body 33 is held at a predetermined position on a straight line by the balance between the magnetic attraction force with the 373 and the reaction force of the diaphragm 12. Therefore, it is possible to prevent the moving body 33 from moving due to vibrations applied from the outside without supplying power to the drive coils 38, 38. As a result, since the power consumption of the electromagnetic linear actuator 3 in the standby state can be suppressed, the power consumption of the positive displacement pump 1 can be suppressed.

  Further, in this example, by having the first fixed body 35 and the second fixed body 36 as the fixed body 34, two drive coils 38 are provided on both sides of the magnet 331 in the direction orthogonal to the moving direction of the moving body 33. , 38 are arranged. As a result, Lorentz force is generated between the magnet 331 and the two drive coils 38, 38, and electromagnetic attraction force and electromagnetic force are generated between the magnet 331 and the first fixed body 35 and the second fixed body 36. A repulsive force can be generated. Further, a magnetic attraction force is generated between the magnet 331 and the first protrusions 372 and 372 and the second protrusions 373 and 373 of the yokes 37 and 37 of the first fixed body 35 and the second fixed body 36. be able to. Therefore, thrust for reciprocating the diaphragm 12 can be obtained using these three forces, and the responsiveness of the positive displacement pump 1 is improved.

(Modification of electromagnetic linear actuator)
FIG. 15 is an explanatory diagram for explaining a modified electromagnetic linear actuator. In FIG. 15, the arrangement of the moving body 33 and the fixed body 34 is shown by the arrangement of the magnet 331, the yoke 37, and the drive coil 38. In FIG. 15, the magnet 331, the yoke 37, and the drive coil 38 are shown cut along a plane orthogonal to the moving direction of the moving body 33.

  In the above embodiment, the first fixed body 35 and the second fixed body 36 are arranged so as to sandwich the moving body 33 from both sides in the apparatus width direction. However, as shown in FIG. Either one of the body 35 and the second fixed body 36 can be omitted. In other words, the moving body 33 may be linearly driven by one fixed body 34 facing the moving body 33.

  Further, the moving body magnet may be formed in a polygonal column shape extending in the vertical direction, and each side surface thereof may be used as a magnetic pole surface, and the number of fixed bodies corresponding to the magnetic pole surface may be provided. In this case, as shown in FIG. 15B, for example, the moving body 33 includes a quadrangular prism-shaped magnet 331A. In the magnet 331A, four side surfaces parallel to the moving direction of the moving body 33 are referred to as magnetic pole surfaces 331a, 331a ′, 331b, and 331b ′, respectively. The four fixed bodies 34 are arranged so that the drive coils 38, 38, 38, 38 face each of the magnetic pole surfaces 331 a, 331 a ′, 331 b, 331 b ′. Since a large thrust can be obtained by increasing the number of the fixed bodies 34, the efficiency of the positive displacement pump can be improved.

  Further, as shown in FIG. 15C, the magnet 331B of the moving body 33 may be a cylindrical one extending in the vertical direction and polarized and magnetized in the circumferential direction. In this case, four fixed bodies 34 corresponding to the magnetic pole surfaces 331a, 331a ′, 331b, and 331b ′ formed by polarization magnetization are provided, and at positions facing the magnetic pole surfaces 331a, 331a ′, 331b, and 331b ′. The four fixed bodies 34 may be arranged so that the four drive coils 38 face the magnetic pole surfaces 331a, 331a ′, 331b, and 331b ′ of the magnet 331B.

  FIG. 16 is an explanatory view for explaining an electromagnetic linear actuator of still another modified example. In FIG. 16, the arrangement of the moving body 33 and the fixed body 34 is shown by the arrangement of the magnet 331, the yoke 37, and the drive coil 38. In FIG. 16, the magnet 331, the yoke 37, and the drive coil 38 are shown cut along a plane parallel to the moving direction of the moving body 33.

  As shown in FIG. 16A, in this example, a yoke 37 and a drive coil 38 are provided on the moving body 33 side to which the diaphragm 12 is attached, and a magnet 331 is provided on the fixed body 34 side. Also in this example, the magnet 331 is arranged so that the magnetic pole surface 331a is parallel to the moving direction of the moving body 33. Further, a first protrusion 372 and a second protrusion 373 projecting toward the magnet 331 are provided at both ends of the yoke 37, and the drive coil 38 is wound in a direction orthogonal to the moving direction of the moving body 33. In this state, the magnet 331 is disposed so as to face the magnetic pole surface 331a. Further, the length dimension of the magnet 331 in the moving direction of the moving body 33 is set to be shorter than the length dimension of the yoke 37 in the moving direction of the moving body 33. In this example, the moving body 33 is held at the raised position 33A by the magnetic attractive force F4 ′ between the magnet 331 and the second protrusion 373. In addition, the moving body 33 is held at the lowered position 33 </ b> B by the magnetic attractive force F <b> 1 ′ between the magnet 331 and the first protrusion 372.

  In the example shown in FIG. 16B, a plurality of fixed bodies 34 including magnets 331 are arranged around a moving body 33 including a yoke 37 and a drive coil 38. In this case, the magnets 331 and 331 of the fixed bodies 34 and 34 are arranged so that the same pole faces the outer peripheral surface of the drive coil 38. Further, in this case, the first protrusion 372 and the second protrusion 373 are formed in a disk shape so that the first protrusion 372 and the second protrusion 373 protrude toward the magnets 331 and 331. Since a large thrust can be obtained by increasing the number of the fixed bodies 34, the efficiency of the positive displacement pump can be improved.

  Also in the example shown in FIG. 16, when power is supplied to the drive coil 38, the direction of the excitation current flowing through the drive coil 38 and the direction of the magnetic field of the magnet 331 are orthogonal to each other according to Fleming's left-hand rule. Will occur. Further, since the drive coil 38 is wound around the yoke 37 according to Ampere's right-handed screw rule, when power is supplied to the drive coil 38, the drive coil 38 and the yoke 37 function as electromagnetic coils (electromagnets). An electromagnetic attractive force and an electromagnetic repulsive force are generated between the electromagnetic coil and the magnet 331. Further, since the first protrusion 372 and the second protrusion 373 are provided at both ends of the yoke 37 extending in the moving direction of the moving body 33, the moving body 33 that moves linearly has the first and second protrusions. When approaching either 372 or 373, a magnetic attractive force is generated between the magnet 331 and the first and second protrusions 372 and 373. That is, in the positive displacement pump 1, the Lorentz force, the electromagnetic attractive force, the electromagnetic repulsive force, and the magnetic attractive force can be used as the thrust of the diaphragm 12.

  Also in this example, the magnetic attractive force acting between the magnet of the moving body 33 and the first protrusion 372 or the second protrusion 373 of the yoke 37 of the fixed body 34 is used as the thrust of the moving body 33. Therefore, after the moving body 33 leaves the ascending position 33A or the descending position 33B, the moving body 33 can be moved even if the current value of the excitation current supplied to the drive coil 38 is reduced. Therefore, the power consumption of the positive displacement pump 1 is reduced as compared with the case where a constant magnitude of excitation current is continuously supplied to the drive coil 38 while the moving body 33 is moved between the raised position 33A and the lowered position 33B. Can be made.

(Modification of positive displacement pump)
Next, a modification of the positive displacement pump will be described with reference to FIG. In the above-described embodiment, the active valve 4 that is driven by power feeding is disposed in the inflow side flow path 9, but a passive valve can be disposed. FIG. 17 is a longitudinal sectional view of a positive displacement pump in which a passive valve is arranged instead of the active valve 4. In addition, since the positive displacement pump 1A of this example has the same configuration as the positive displacement pump 1 of the above-described embodiment, the corresponding components are denoted by the same reference numerals and description thereof is omitted.

  In the positive displacement pump 1 </ b> A, the inflow pipe 6 protrudes from the right side portion of the upper end surface of the upper housing 21. The upper end of the inflow pipe 6 is a fluid inlet 6a. A circular fifth recess 71 that is recessed upward is provided on the right side portion of the lower end surface of the upper housing 21. A lower end opening 72 a of the fourth flow path 72 communicating with the inflow pipe 6 is exposed at the central portion of the ceiling surface of the fifth recess 71.

  A circular second upper protrusion 73 that fits into the fifth recess 71 of the upper housing 21 is formed on the right side of the upper end surface of the lower housing 22. A circular sixth recess 74 that is recessed downward is formed at the center of the second upper protrusion 73. The second upper protrusion 73 is fitted in the fifth recess 71, and an inflow side valve chamber 75 is formed coaxially with the inflow pipe 6 by the fifth recess 71 of the upper housing 21 and the sixth recess 74 of the lower housing 22. ing. An O-ring 76 is disposed between the outer peripheral surface of the second upper protrusion 73 and the inner peripheral surface of the fifth recess 71. A passive valve 77 is formed in the inflow side valve chamber 75.

  An in-housing flow path 78 is formed between the inflow side valve chamber 75 and the valve chamber 13 of the lower housing 22. The in-housing flow path 78 includes a first flow path portion 79 extending downward from the inflow side valve chamber 75 and a second flow path extending from the lower end of the first flow path portion 79 in the apparatus width direction toward the valve chamber 13. A portion 80 and a third flow path portion 81 extending upward from the left end of the second flow path portion 80 are provided. The upper end opening 79 a of the first flow path portion 79 is exposed at the central portion of the circular bottom surface 75 a of the inflow side valve chamber 75, and the upper end opening 81 a of the third flow path portion 81 is the central portion of the circular bottom surface 13 a of the valve chamber 13. Is exposed. The pump chamber 8 is formed at the central portion of the lower housing 22 in the device width direction, and the central portion of the second flow path portion 80 in the device width direction communicates with the upper end portion of the pump chamber 8. An electromagnetic linear actuator 3 is disposed below the pump chamber 8.

  The passive valve 77 includes a valve seat 82 in which a lower end opening 72a of the fourth flow path 72 is formed, and a valve body 83 that contacts the valve seat 82 from the downstream side in the fluid flow direction and closes the lower end opening 72a. And a biasing member that is inserted between the valve body 83 and the circular bottom surface 75a of the inflow side valve chamber 75 and biases the valve body 83 toward the valve seat 82 with a predetermined biasing force. Here, the valve seat 82 is a circular ceiling surface 75 b of the inflow side valve chamber 75, and the urging member is a compression coil spring 84. The valve body 83 has the same configuration as the valve body 112 of the check valve 11, and the compression coil spring 84 has the same configuration as the compression coil spring 113 of the check valve 11. .

  Here, the passive valve 77 has a predetermined pressure equal to or higher than a predetermined urging force by the compression coil spring 84 in the inflow side flow path 9 when the negative pressure is generated in the pump chamber 8 due to the expansion of the volume of the pump chamber 8. Is applied in the outflow direction, the lower end opening 72a of the fourth flow path 72 is opened. Further, the upper end opening 79a is closed when pressure is applied to the inflow side channel 9 in the direction opposite to the outflow direction.

  In addition, as a movable body for changing the volume of the pump chamber 8, a thing other than the diaphragm 12 can be used. For example, like a cylinder, you may comprise so that the bottom face of the pump chamber 8 may be raised / lowered with the movement of the mobile body 33. FIG.

1.1A positive displacement pump 2. Pump unit 3. Electromagnetic linear actuator 4. Active valve 5. Outflow pipe 5a Fluid outlet 6. Inflow pipe 6a Fluid inlet 8. Pump chamber , 9, inflow side flow path, 10 outflow side flow path, 11 check valve, 12 diaphragm (movable body), 12a connection part, 13 valve chamber, 13a circular bottom, 13b circular ceiling surface, 14.15.O-ring, 21.upper housing, 22.lower housing, 30.actuator case, 31.upper case, 32.lower case, 32a.upper end surface, 33.moving body, 33A, raised position, 33B・ Lower position, 34 ・ Fixed body, 35 ・ First fixed body, 36 ・ Second fixed body, 37 ・ Yoke, 38 ・ Drive coil, 38 a ・ Outer peripheral surface part, 39 ・ Spacer, 40 ・ Guide mechanism, 41 ・ Cylinder Department, 42 Orif 43, valve body, 43A, closed position, 43B, open position, 44, valve seat, 45, fluid flow path, 46, drive coil, 47, coil bobbin, 48, yoke, 49, rubber packing, 50, Presser plate, 71, fifth recess, 72, fourth flow path, 72a, lower end opening, 73, second upper protrusion, 74, sixth recess, 75, inflow side valve chamber, 75a, circular bottom, 75b, circular Ceiling surface, 76 / O-ring, 77 / passive valve, 78 / housing channel, 79 / first channel part, 79a / upper opening, 80 / second channel part, 81 / third channel part, 81a・ Upper end opening, 82 ・ Valve seat, 83 ・ Valve body, 83 a ・ Outer peripheral surface part, 84 ・ Compression coil spring, 111 ・ Valve seat, 112 ・ Valve body, 112 a ・ Closed part, 112 b ・ Annular projection, 112 c ・ Positioning 113, compression coil spring, 113a Lower end opening, 211 / first recess, 212 / first flow path, 212a / lower end opening, 221 / upper projection, 222 / second recess, 223 / lower projection, 224 / third recess, 224a / ceiling surface 225, second flow path, 225a, lower end opening, 225b, upper end opening, 226, fourth recess, 226a, large diameter portion, 226b, small diameter portion, 226c, upper end portion, 227, third flow path, 311, upper Plate, 312 to 315, side plate, 316, connection portion, 316a, through hole, 316b, stepped portion, 317, engagement recess, 318, guide groove, 318a, upper edge, 322, recess, 323, groove, 324, penetration Hole, 325, engaging protrusion, 331, 331A, 331B, magnet, 331a, 331b, 331a ', 331b', magnetic pole surface, 331c, upper end surface, 332, magnet holder, 332a, vertical frame portion, 3 2b · upper frame portion, 332c · lower frame portion, 333 · guide projection portion, 334 · connection portion, 335 · guide shaft, 371 · shaft portion, 372 · first projection portion, 373 · second projection portion, 421 · Cylindrical part, 422, flange part, 423, orifice, 423a, lower end opening, 424, annular recess, 431, pipe, 432, magnet, 433, magnetic plate, 434, magnetic plate, 435, lid plate, 436, bottom plate 437, rubber sheet, 471, engagement recess, 472, cylindrical body, 473, flange, 474, projection, D1, first direction, D2, second direction, I1 to I3, excitation current, P1 ~ P3 · section, S1 · S2 · pulse width, t0 · process start time, t1 · process end time

Claims (6)

A movable body that can move directly;
A fixed body for linearly moving the moving body;
A movable body attached to the movable body to change the capacity of the pump chamber,
Either one of the moving body and the fixed body includes a magnet having a magnetic pole surface parallel to the moving direction of the moving body,
The other of the movable body and the fixed body includes a yoke and a drive coil facing the magnetic pole surface with a certain gap in a state of being wound around the yoke,
The yoke includes a shaft portion extending in a moving direction of the moving body, a first protrusion projecting from one end portion of the shaft portion in the moving direction of the moving body toward the magnet, and the moving body. A second protrusion protruding from the other end portion of the shaft portion in the moving direction toward the magnet;
The drive coil is wound in a direction orthogonal to the moving direction of the movable body around a portion of the yoke between the first protrusion and the second protrusion.
The positive displacement pump according to claim 1, wherein a length of the magnet in the moving direction of the moving body is shorter than a length of the yoke in the moving direction of the moving body. In claim 1,
In a state where the positive displacement pump is not operated, the moving body is moved by a magnetic attraction force between the magnet and the first protrusion or a magnetic attraction force between the magnet and the second protrusion. A positive displacement pump, wherein the positive displacement pump is selectively held at one position or a second position different from the first position. In claim 1 or 2,
The moving body includes the magnet,
The fixed body includes the yoke and the drive coil,
The magnet includes a first magnetic pole surface parallel to a moving direction of the moving body, and a second magnetic pole surface facing a direction opposite to the first magnetic pole surface, and the first magnetic pole surface and the second magnetic pole surface. Two poles are magnetized so that the surface is a different pole,
The fixed body includes a first fixed body in which the drive coil faces the first magnetic pole surface and a second fixed body in which the drive coil faces the second magnetic pole surface. The positive displacement pump. In claim 3,
Each drive coil of each fixed body has a rectangular cross-sectional shape by a plane orthogonal to the moving direction of the moving body, and the outer peripheral surface portion which is one long side of the cross-sectional shape is each magnetic pole of the magnet Facing the surface,
The positive displacement pump according to claim 1, wherein a width dimension of each magnetic pole surface in a direction orthogonal to a moving direction of the moving body is shorter than a width dimension of the outer peripheral surface portion in a direction orthogonal to the moving direction of the moving body. In claim 4,
A case covering the first fixed body and the second fixed body;
A guide mechanism for linearly moving the movable body while maintaining a constant gap between each magnetic pole surface of the movable body and each drive coil of each fixed body,
The guide mechanism includes a guide protrusion protruding from the movable body, and a guide groove provided between the first fixed body and the second fixed body of the case. Type pump. In any one of claims 1 to 5,
The positive displacement pump, wherein the movable body is a diaphragm.

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