JP4547138B2 - Diaphragm pump using a reciprocating motor - Google Patents

Description

  The present invention relates to a diaphragm pump using a reciprocating motor used for a metering injection pump, a vacuum pump, or the like.

  In recent years, diaphragm pumps have been utilized in various fields such as quantitative injection. Such a diaphragm pump is desired to have high accuracy of quantitative injection and low noise.

  As a drive source for driving the diaphragm pump, there is one using a solenoid as shown in FIG.

  As described above, the diaphragm pump using the solenoid has high noise. This is because the plunger 12 to which the shaft 11 is fastened and the coil case 14 in which the coil 13 is housed collide at a very high speed by instantaneous horizontal movement.

In order to solve such a noise problem, one using a reciprocating motor as a drive source of a diaphragm pump is known (for example, see Patent Document 1). This reciprocating motor has a structure in which the mover fastened to the shaft and the stator connected to the motor frame do not collide. Therefore, noise such as a diaphragm pump using a solenoid is not generated.
JP-A-8-68379

  In the first place, the diaphragm pump is intended to inject a fixed amount of chemicals and the like. In a diaphragm pump using a reciprocating motor, the flow rate discharged while the reciprocating motor shaft reciprocates once is constant. The stroke length of the shaft is determined by the drive current flowing through the reciprocating motor.

  In order to change the discharge flow rate per unit time, it was necessary to change the drive frequency of the reciprocating motor. In this way, if the drive frequency is changed, the impedance of the coil constituting the reciprocating motor will change, so the driving current of the reciprocating motor will change and the shaft stroke length will not be constant. There was a problem that could not.

  The reciprocating motor has a structure in which a shaft is fastened to a mover having a magnetic material such as iron, and a stator made of an electromagnetic steel plate or the like is fastened to a motor frame at a position facing the magnetic material. Further, a motor coil is arranged around the stator, and the mover and the shaft are only held at the center position by a leaf spring or the like fastened to the motor frame, and the reciprocating movement of the shaft is positioned. It wasn't.

  For this reason, the stroke length of the shaft fluctuates due to the pressure of the pipe line for injecting the chemical solution and the like, and there is a problem that the accuracy of quantitative injection is lowered.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a diaphragm pump using a reciprocating motor that can perform quantitative injection with high accuracy and that is low in noise.

The invention of claim 1, wherein, in a diaphragm pump using a reciprocating motor for outputting a discharge rate corresponding to the stroke of the diaphragm in conjunction with the reciprocation of the output shaft of the reciprocating motor, a current flowing before Symbol reciprocating motor a current detector for detecting a constant current control unit for controlling the current flowing through the reciprocating motor detected by the current detection unit of this is constant current, provided on an output shaft of the reciprocating motor And a stopper that is fixed to a stator or motor frame of the reciprocating motor and a part of which is in contact with the notch so that the reciprocating stroke length of the output shaft can be regulated. It is characterized by comprising .

A second aspect of the present invention is the diaphragm pump according to the first aspect, wherein the stopper is circular and a plurality of notches are provided in a radial direction.

The invention according to claim 3 is the diaphragm pump according to claim 2, wherein the stopper is formed by laminating thin plates.

According to the onset bright, detected by the current detector the current flowing in the reciprocating motor, the current value that is to be controlled by the constant current control unit to be constant values, changing the discharge quantity of the diaphragm pump Therefore, by changing the frequency of the drive signal supplied to the reciprocating motor, the value of the current flowing in the reciprocating motor can be kept constant even if the impedance of the reciprocating motor changes. Therefore, even if the frequency of the drive signal is changed, the stroke length of the diaphragm pump can be kept constant, so that quantitative injection can be performed with high accuracy.

According to the onset bright, since the stroke length of the diaphragm is determined by a constant current value, it is possible to be able to at the highest working pressure of the diaphragm pump obtaining a predetermined stroke length.

According to the present invention, it provided the notch on the output shaft of the reciprocating motor, when the output shaft is reciprocated, since so as to abut the stopper notch, the stroke length of the forward backward motor - Can be fixed.

According to the onset bright, it is possible to reduce the propagation of vibrations to the stator and the motor frame of the reciprocating motor by a stopper. As a result, the noise level of the diaphragm pump can be reduced.

According to the present invention, by laminating the multiple sheet, it is possible to maintain the mechanical strength of the stopper.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a diaphragm pump using a reciprocating motor. In the figure, 21 is a cylindrical pump casing. One end of the pump casing 21 is provided with a suction port 22 for sucking liquid such as a chemical solution, and the other end is provided with a discharge port 23 for discharging liquid, and a pump chamber 24 is formed from the side surface to the vicinity of the central axis. Has been.

  A suction line 25 is formed between the suction port 22 and the pump chamber 24, and a discharge line 26 is formed between the pump chamber 24 and the discharge port 23.

  Furthermore, a check valve 27 that enables suction of liquid only from the suction port 22 toward the pump chamber 24 is interposed in the suction pipe line 25. Further, a check valve 28 that enables discharge of liquid from the pump chamber 24 only in the direction of the discharge port 23 is interposed in the discharge pipe line 26.

  Reference numeral 31 denotes a motor frame of the reciprocating motor 30. A cylindrical motor cover 32 is attached to the motor frame 31.

  Furthermore, one end of four support pins 33a to 33d is riveted to the motor frame 31 in the circumferential direction. In FIG. 1, only 33a and 33c are shown.

  A stopper 41, a disc-shaped plate spring 42, a stator 43, and a disc-shaped plate spring 44, which will be described in detail later with reference to FIG. 2, are fixed to the support pin 33a from the motor frame 31 side.

  Furthermore, the stopper 41, the disk-shaped leaf spring 42, the stator 45, and the leaf spring 44 are also fixed to the support pin 33c.

  The shaft (output shaft) 51 of the reciprocating motor 30 is supported at both ends by leaf springs 42 and 44.

  A support member 53 is fixed to one end side of the shaft 51. The support member 53 is formed with a notch 52 having a constant width in which a part of the stopper 41 is projected and retracted.

  Furthermore, the one end side of the shaft 51 has a small-diameter portion 51a having a small diameter. A cylindrical piston member 62 is attached to the small diameter portion 51a via a diaphragm 61.

  A first coil 71 is wound around the stator 43, and a second coil 72 is wound around the stator 45.

  Further, a permanent magnet 73 is magnetized on the side surface of the stator 43 facing the shaft 51 in the axial direction of the shaft 51, and the side surface of the stator 45 facing the shaft 51 in the axial direction of the shaft 51. A permanent magnet 74 is magnetized. Here, the polarities of the permanent magnets 73 and 74 are the same.

  The first coil 71 and the second coil 72 are connected in series as shown in FIG. 4, and a current I (for example, shown in FIG. 5) flowing through the first coil 71 and the second coil 72 is controlled. It is controlled by a drive signal from the unit 81. The control unit 81 includes a current detection unit 81a that detects the current I, and a constant current control unit 81b that keeps the value of the current I detected by the current detection unit 81b constant.

  Further, the winding direction is determined so that the direction of the magnetic field generated by the current I flowing through the first coil 71 and the second coil 72 is the same.

  Therefore, when a current as shown in FIG. 5 or FIG. 6 flows in the first coil 71 and the second coil 72, the current direction periodically changes, so that the current flows in the first coil 71 and the second coil 72. The magnetic field generated by the current causes the magnetic fields of the permanent magnets 73 and 74 to be increased or decreased.

  As a result, the shaft 51 reciprocates periodically in the axial direction. By reciprocating the shaft 51, the diaphragm 61 also reciprocates, and the piston member 62 also reciprocates.

  The magnitude of the reciprocating motion of the diaphragm 61, that is, the stroke length ΔL is determined by the magnitude of the current I.

  In FIG. 1, the end surface of the piston member 62 on the pump chamber 24 side has a step, but the upper half (indicated by reference numeral 62 a) indicates the end position of the discharge process for discharging the liquid in the pump chamber 24, and the lower side Half (indicated by reference numeral 62 b) indicates the end position of the suction step for sucking the liquid into the pump chamber 24.

  Reference numeral 91 denotes a connector. A connector 92 connected to a control line 92 from the control unit 81 is connected to the connector 91. Thereby, an electric circuit as shown in FIG. 4 is formed.

  The control unit 81 includes a current detection unit 81a that detects the current I flowing through the first coil 71 and the second coil 72, and a constant current control unit 81b that maintains the current I at a constant value. This makes the stroke length ΔL constant by controlling the current value I to be kept constant.

  Thus, by making the stroke length ΔL constant, the end position of the discharge process for discharging the liquid in the pump chamber 24 and the end position of the suction process for sucking the liquid into the pump chamber 24 can be made constant. The amount of liquid discharged from the chamber 24 can be kept constant.

  Next, the configuration of the stopper 41 will be described with reference to FIGS. As shown in FIG. 2, the stopper 41 is formed by laminating a plurality of circular thin plates. A plurality of notches 100a to 100f are provided from the center position of the stopper 41 to approximately half the radial direction. Tongue portions 101a to 101f are formed by adjacent notches 100a to 100f.

  Then, as shown in FIG. 3, the tongue portions 101 a to 101 f appear and disappear in the cutout portion 52.

  As described above, the notch 52 having a constant width is provided on the shaft of the reciprocating motor 30, and when the output shaft reciprocates, the stopper 41 protrudes into the notch 52 and comes into contact with both ends of the notch 52. As a result, the stroke length ΔL of the reciprocating motor 30 can be kept constant even when the pressure in the pipeline, for example, the discharge pipeline 26 fluctuates.

  Next, the operation will be described. A sine wave current I as shown in FIG. 5 flows through the first coil 71 and the second coil 72 by the control of the drive signal from the control unit 81.

  As a result, the diaphragm 61 reciprocates with a stroke length ΔL corresponding to the magnitude of the sine wave current I.

  As a result, the piston member 62 reciprocates in the pump chamber 24 with a stroke length ΔL. That is, the piston member 62 reciprocates between the end position 62b of the suction process for sucking the liquid into the pump chamber 24 and the end position 62a of the discharge process for discharging the liquid in the pump chamber 24.

  Accordingly, the liquid sucked into the pump chamber 24 in the suction process is discharged through the discharge port 23 in the discharge process. At this time, the discharge amount of the liquid discharged from the discharge port 23 is determined by the stroke length ΔL.

  This stroke length ΔL is determined by the magnitude of the sine wave current I flowing through the first coil 71 and the second coil 72.

  By the way, the magnitude of the sine wave current I flowing through the first coil 71 and the second coil 72 is detected by the current detector 81a. The constant current control unit 81b controls the sine wave current I flowing in the first coil 71 and the second coil 72 to be kept constant.

  Therefore, if the sine wave current I flows through the first coil 71 and the second coil 72, the amount of liquid discharged while the pump member 62 reciprocates once is constant.

  By the way, when the frequency of the sine wave current I is varied, the number of times the piston member 62 reciprocates with a stroke length ΔL per unit time changes.

  Thereby, the amount of liquid ejected per unit time is varied.

  At this time, the impedances of the first coil 71 and the second coil 72 change according to the frequency of the drive signal output from the control unit 81. As a result, the sine wave current I also changes.

However, in the present invention, the current value of the sine wave current I is detected by the current detector 81a, and the constant current controller 81b is provided so as to keep this current value constant. Even if the impedance of the first coil 71 and the second coil 72 changes,
The current flowing through the first coil 71 and the second coil 72 can be kept constant.

  As described above, the current flowing through the first coil 71 and the second coil 72, that is, the current flowing through the reciprocating motor 30 is detected by the current detection unit 81a, and the constant current control unit is set so that the current value becomes a constant value. Since the control is performed by 81b, even if the impedance of the reciprocating motor changes by changing the frequency of the drive signal supplied to the reciprocating motor in order to change the discharge amount of the diaphragm pump, the current flowing to the reciprocating motor The value can be kept constant. Therefore, even if the frequency of the drive signal is changed, the stroke length of the diaphragm pump can be kept constant, so that quantitative injection can be performed with high accuracy.

  Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 7, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the second embodiment, a position detection unit 100 that detects the position of the shaft 51 of the reciprocating motor 30 in the axial direction is provided on the inner wall of the motor cover 32. A position signal indicating the axial position of the shaft 51 of the reciprocating motor 30 detected by the position detection unit 100 is input to the control unit 81.

  The control unit 81 controls the current flowing through the first coil 71 and the second coil 72 according to the position signal indicating the axial position of the shaft 51 of the reciprocating motor 30 detected by the position detection unit 100. Then, control is performed to keep the stroke length ΔL of the reciprocating motor 30 constant.

  In this way, the position of the shaft 51 of the reciprocating motor 30 is detected by the position detection unit 100, and the current flowing through the reciprocating motor 30 according to the position of the shaft 51 of the reciprocating motor 30 detected by the position detection unit 100. Since the stroke amount ΔL of the diaphragm interlocked with the reciprocating motion of the shaft 51 of the reciprocating motor is controlled to be constant, the frequency of the drive signal supplied to the reciprocating motor 30 and the pipe pressure are controlled. Even if changes, the reciprocating motor can always be driven with a constant stroke length ΔL.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, pump casings 21 a and 21 b are provided on both sides of the shaft 51 of the reciprocating motor 30. Pump chambers 24a and 24b are provided in the pump casings 21a and 21b, respectively. The stoppers 41a and 41b and the diaphragms 61a and 61b are also provided on both sides of the reciprocating motor 30, but may be stoppers (41a and 41b) only on one side. Other configurations are the same as those in FIG.

  Thus, by providing the pump casings 21a and 21b on both sides of the shaft 51 of the reciprocating motor 30, the other pump can be used while the suction process for sucking the liquid is performed in the pump chamber 24a of the one pump casing 21a. A discharge process for discharging liquid is performed in the pump chamber 24b of the casing 21b.

  In this way, uniform injection can be achieved by adopting a discharge process in which the other pump discharges liquid during the suction process of one pump.

  Furthermore, in the above embodiment, the control unit 81 controls the current flowing in the reciprocating motor 30 to be constant. However, the current flowing in the reciprocating motor 30 is variably controlled to control the reciprocating motor 30. The stroke length ΔL may be varied to vary the discharge flow rate.

1 is a cross-sectional view of a diaphragm pump using a reciprocating motor according to a first embodiment of the present invention. FIG. 3 is a plan view of the stopper according to the first embodiment. FIG. 3 is a cross-sectional view of a main part showing a state where the stopper according to the first embodiment is mounted in the cutout part. FIG. 3 is an electric circuit diagram for driving a diaphragm pump using the reciprocating motor according to the first embodiment. FIG. 6 is a waveform diagram of a drive signal that drives a diaphragm pump using the reciprocating motor according to the first embodiment. FIG. 6 is a waveform diagram of a drive signal that drives a diaphragm pump using the reciprocating motor according to the first embodiment. FIG. 5 is a cross-sectional view of a diaphragm pump using a reciprocating motor according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view of a diaphragm pump using a reciprocating motor according to a third embodiment of the present invention. Sectional drawing of the principal part of the diaphragm pump using the conventional solenoid.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 ... Pump casing, 41 ... Stopper, 43 ... Stator, 51 ... Shaft 81 ... Control part, 81a ... Current detection part, 81b ... Constant current control part.

Claims (3)

In a diaphragm pump using a reciprocating motor that outputs a discharge amount corresponding to the stroke amount of the diaphragm linked to the reciprocating motion of the output shaft of the reciprocating motor,
A current detector that detects a current that determines a stroke length of the diaphragm by flowing in the reciprocating motor;
A constant current control unit that controls the current flowing through the reciprocating motor detected by the current detection unit to have a constant current value;
A notch provided in the output shaft of the reciprocating motor;
A stopper fixed to the stator or motor frame of the reciprocating motor, a part of which is in contact with the notch, so that the reciprocating stroke length of the output shaft can be regulated. Diaphragm pump using a reciprocating motor characterized by   The diaphragm pump using a reciprocating motor according to claim 1, wherein the stopper has a circular shape and is provided with a plurality of notches in the radial direction.   3. The diaphragm pump using a reciprocating motor according to claim 2, wherein the stopper is a laminate of thin plates.

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