JP2009007976A - Electromagnetic pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic pump capable of being built up with a valve such as a direction change valve for chucking a machine tool or greatly saving the energy of a clamp circuit. <P>SOLUTION: The electromagnetic pump 30 has a pump part 32 engaged with a solenoid valve 31. The pump part 32 has a body 48 engaged with a stopper 38 via a screw mechanism, and a rod 43 of the stopper 38 is connected to one end of a piston member 49 slidably fitted into the body 48. The other end of the piston member 49 is thrust by a spring member 51 engaged with a piston shaft 52 mounted on the body 48. A suction passage 64 and a discharge passage 57 are communicated with the pump chamber 53, and a discharge check valve 62 is provided on the way of the discharge passage 57 and a suction check valve 60 is provided on the way of the suction passage 64. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic pump, and more particularly to a structure of an electromagnetic pump capable of discharging a liquid by operating an electromagnetic coil.

Conventionally, this type of electromagnetic pump discharges pressure oil by an electromagnetic force (attraction force) generated when an electromagnetic coil is excited, and by the elastic force of a spring member bent by the attraction force when the electromagnetic coil is not excited. The present applicant has proposed a technique in which oil is sucked from the tank port when the position of the piston of the electromagnetic pump is restored (see, for example, Patent Document 1).
JP 2007-51567 A

However, the electromagnetic pump disclosed in Patent Document 1 often excites the electromagnetic coil frequently. In this case, the temperature of the electromagnetic coil rises, so that the resistance of the electromagnetic coil increases. As a result, although the same voltage is continuously excited in the electromagnetic coil, the current value decreases and the attractive force of the electromagnetic coil decreases.
Further, when the temperature of the electromagnetic coil of the electromagnetic pump is low, such as when the air temperature is low, the resistance of the electromagnetic coil decreases, and conversely, the current value increases and the attractive force increases.
Furthermore, the set pressure of the conventional electromagnetic pump is determined by a pressure balance including the attractive force of the electromagnetic coil, the elastic force of the spring member, and the generated hydraulic pressure. Therefore, if the suction force changes during the operation of the electromagnetic pump, there is a possibility that the initially set pressure cannot be maintained.
The present invention has been made in order to solve the above-described problems. The spring member sucks pressure oil by the suction force of the coil when the electromagnetic coil is excited, and is bent by the suction force of the coil when the coil is not excited. It is an object of the present invention to provide an electromagnetic pump that can continue to maintain a set pressure regardless of changes in coil temperature of the electromagnetic pump by discharging pressure oil with the elastic force.

In order to achieve the above object, an invention according to claim 1 includes an electromagnetic valve member having an electromagnetic coil,
A pump member having a pump body liquid-tightly engaged with the electromagnetic valve member;
An electromagnetic pump comprising:
Oil is sucked by the suction force of the electromagnetic coil when the electromagnetic coil is excited, and pressure oil is discharged by the elastic force of the spring member bent by the suction force of the electromagnetic coil when the electromagnetic coil is not excited. .
According to the present invention, the oil is sucked by the suction force of the coil when the electromagnetic coil is excited, and the pressure oil is discharged by the elastic force of the spring member bent by the suction force of the coil when the coil is not excited. As a result, the set pressure can be maintained regardless of changes in the coil temperature of the electromagnetic pump.

  In the present invention, the force for discharging the pressure oil can be set not by the suction force of the electromagnetic coil but by the elastic force on the spring member, so there is no fluctuation in the set pressure due to the oil temperature or the temperature change of the electromagnetic coil, The set pressure can be maintained.

A preferred embodiment of the electromagnetic pump of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a schematic structure of an electromagnetic pump 30 according to an embodiment of the present invention.
As shown in FIG. 1, the electromagnetic pump 30 basically includes an electromagnetic valve (electromagnetic valve member) 31 that generates a suction force and a pump unit (pump member) 32.

  The electromagnetic valve 31 includes a coil body 33 including an electromagnetic coil 34 that generates a magnetic field, a coil bobbin 35, a coil case 35a that serves as an external magnetic path, and rings 36 and 37, and a function of a fixed core when a magnetic field is applied. A plunger 39 which is a movable iron core sucked by a stopper 38 having a guide, a guide 40 for supporting the plunger 39 and applying a magnetic field to the plunger 39, and a plunger 39 from the guide 40 to the stopper 38 via the plunger 39. The sleeve body 42 is provided with a nonmagnetic material 41 welded so that a magnetic field flows. In this case, the electromagnetic coil 34 is attached to the coil bobbin 35 and is inserted into the coil bobbin 35 together with the coil case 35a and the rings 36 and 37, and is inserted into a mold (not shown) and is then coiled by the injection molding machine. Is formed.

A rod 43 abutting on the plunger 39 is inserted into the stopper 38 so as to be freely displaceable at an axial center thereof, and one end of the rod 43 is slidable on a main body 48 (pump main body) of the pump portion 32. It is in contact with the piston member 49 that is inserted.
When the coil main body 33 and the sleeve main body 42 are assembled, the sleeve 44 is inserted into the hole 33a of the coil main body 33, and the fixing nut 46 is screwed into the screw portion 45a formed in the boss portion 45 of the sleeve 44. It is worn. Further, the protrusion 47 formed at one end of the stopper 38 is joined to a screw mechanism 59 a formed in the pump chamber 53 of the main body 48 of the pump unit 32.

  In the main body 48, a piston member 49 is slidably fitted on the same axis as the rod 43. One end of the piston 49 member abuts on the rod 43, and the other end receives the spring member 51 by the retainer 50. Via the piston shaft 52. The piston shaft 52 is movably provided in a screw mechanism (not shown) provided in a boss portion 55 screwed into a screw mechanism 59b in a pump chamber 54 opened in an end surface of the main body 48, and the piston shaft 52 is axially centered. When displaced in the direction, the elastic force of the spring member 51 is adjusted. Therefore, by adjusting the elastic force of the spring member 51, the return force of the piston member 49 when the solenoid valve 31 is not excited is adjusted.

On the other hand, the suction passage 64 and the discharge passage 57 formed in the main body 48 communicate with the pump chamber 53. The suction path 64 communicates with a tank port 68 through which valve return oil passes through a suction check valve (pressure adjusting mechanism) 60, and the discharge path 57 is a liquid supply destination (not shown) A. Connected to port 66. Further, a discharge check valve (pressure adjusting mechanism) 62 is provided in the middle of the discharge path 57. The discharge check valve 62 opens when the liquid flows from the pump chamber 53 to the discharge passage 57, and closes when the liquid flows from the suction passage 64 to the pump chamber 53. Here, a pump mechanism 63 is formed by the pump chamber 53, the suction path 64, the discharge path 57, the suction check valve 60, and the discharge check valve 62.
The pump chamber 54 is connected to a flow path 56 that communicates with the tank port 68. The flow path 56 has a function of sucking liquid from the tank port 68 into the pump chamber 54 when the piston member 49 is displaced in the arrow X direction. When displaced in the Y direction, the liquid stored in the pump chamber 54 is returned to the tank port 68. Reference numeral 65 indicates a pressure port connected to a pressure supply source (not shown), and reference numeral 67 indicates a B port communicating with a liquid supply destination. The attachment hole 69 is for attaching the electromagnetic pump 30 to a sub-plate (not shown).

The electromagnetic pump 30 according to the embodiment of the present invention is basically configured as described above, and the operation of the electromagnetic pump 30 will be described with reference to FIG.
FIG. 2A shows a state where the electromagnetic coil 34 is not excited (OFF). In this state, the piston member 49 is displaced in the arrow X direction via the retainer 50 by the elastic force of the spring member 51. Therefore, the rod 43 is displaced in the arrow X direction together with the plunger 39.

Next, as shown in FIG. 2B, when the electromagnetic coil 34 is energized (ON), the plunger 39 is displaced in the direction of the arrow Y because it is attracted to the stopper 38. Therefore, the piston member 49 is pressed by the rod 43 and the spring member 51 is bent in the arrow Y direction by the retainer 50. As a result, the volume of the pump chamber 53 increases, so that the pump chamber 53 becomes negative pressure, and the suction check valve 60 is opened by the amount corresponding to the increase in volume, and pressure oil is sucked from the tank port 68 through the suction passage 64. .
Further, since the volume of the pump chamber 54 is reduced, the excess pressure oil corresponding to the reduced amount is returned to the tank port 68 through the flow path 56.

  On the other hand, when the electromagnetic coil 34 is changed from the excited (ON) state to the non-excited (OFF) state, as shown in FIG. 2 (A), the elastic force of the spring member 51 bent by the attractive force of the electromagnetic coil 34 is obtained. The piston member 49 is displaced in the direction of the arrow X via the retainer 50 by the generated force. Therefore, the rod 43 is displaced in the arrow X direction together with the plunger 39. At that time, the volume of the pump chamber 53 decreases, and excess pressure oil corresponding to the volume decrease of the pump chamber 53 opens the discharge check valve 62 and is discharged to the A port 66 through the discharge check valve 62. . In this case, the volume of the pump chamber 54 increases by the amount of displacement of the piston member 49 in the direction of the arrow X, so that the oil corresponding to the increased volume is filled into the pump chamber 54 from the tank port 68 via the suction passage 56.

It is a longitudinal section showing a schematic structure of an electromagnetic pump concerning an embodiment of the invention. 2A and 2B are operation explanatory diagrams of the electromagnetic pump of FIG. 1, in which FIG. 1A shows a non-excited state, and FIG. 1B shows an excited state.

Explanation of symbols

30 Solenoid pump 31 Solenoid valve
32 Pump part 34 Electromagnetic coil 48 Main body 56 Suction path 57 Discharge path 60 Discharge check valve 62 Suction check valve 65 Pressure port 66 A port 67 B port 68 Tank port

Claims (1)

An electromagnetic valve member having an electromagnetic coil;
A pump member having a pump body liquid-tightly engaged with the electromagnetic valve member;
An electromagnetic pump comprising:
Oil is sucked by the suction force of the electromagnetic coil when the electromagnetic coil is excited, and oil is discharged by the elastic force of the spring member bent by the suction force of the electromagnetic coil when the electromagnetic coil is not excited. pump.

Images