JP2007278171A - Solenoid and electromagnetic pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid with its service life extendable by preventing a plunger from being tilted relative to the sliding direction. <P>SOLUTION: This solenoid 34 comprises an exciting coil 35, a cylindrical guide pipe 37 which is installed on the inside of the exciting coil 35 and in which a plunger insertion hole 39 is formed, a fixed yoke 36 so disposed as to surround the exciting coil 35, and the plunger 38 slidably disposed in the plunger insertion hole 39 of the guide pipe 37, disposed at a gap between itself and the fixed yoke 36, and having a magnetic circuit formed between itself and the fixed yoke 36. The center axis of the plunger insertion hole 39 of the guide pipe 37 is deviated from the center axis of the outer periphery of the guide pipe 37. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a solenoid that reciprocally drives a plunger by flowing an exciting current through an exciting coil, and an electromagnetic pump that operates a diaphragm by reciprocatingly driving the plunger.

A diaphragm pump, which is a type of positive displacement pump, is a device that changes the volume of a diaphragm chamber (pump chamber) by reciprocating the diaphragm and allows the fluid to be sucked and discharged.
An electromagnetic pump using a solenoid as a drive source for reciprocating the diaphragm is generally known (see, for example, Patent Document 1).

A conventionally known electromagnetic pump 10 is shown in FIGS.
The diaphragm 12 is disposed in the diaphragm chamber 13, and a plunger 14 is fixed at the center. The plunger 14 is slidably provided in a plunger insertion hole 16 formed in a guide pipe 15 disposed inside an excitation coil (not shown in FIGS. 4 and 5).

The diaphragm chamber 13 of the electromagnetic pump 10 is provided with a suction valve 17 that sucks fluid into the diaphragm chamber 13 from the outside of the pump and a discharge valve 18 that discharges fluid from the diaphragm chamber 13 to the outside of the pump.
The suction valve 17 and the discharge valve 18 shown here are check balls, which are disposed in a suction hole 19 and a discharge hole 20 that communicate with the diaphragm chamber 13 and the outside of the pump, respectively. Operates to open and close.

The check ball 17 on the suction side is urged by a spring 21 so as to close an outer opening 22 formed between the suction hole 19 and the outside of the pump, and the plunger 14 moves to the other side to move to the diaphragm chamber. When the volume of 13 increases, it moves to the diaphragm chamber 13 side against the biasing force of the spring 21 and opens the suction hole 19.
At this time, the check ball 18 on the discharge side is urged by the spring 23 so as to close the inner opening 24 formed between the discharge hole 20 and the diaphragm chamber 13, and closes the discharge hole 20 as it is. ing.

  When the plunger 14 moves to one side and the volume of the diaphragm chamber 13 decreases, the check ball 17 on the suction side is pressed by the fluid in the diaphragm chamber 13 and moves to the outside of the pump to close the suction hole 19. The check ball 18 on the discharge side is pressed by the fluid in the diaphragm chamber 13 and moves to the outside of the pump to open the discharge hole 20.

Japanese Patent Laid-Open No. 5-87005 (FIG. 2 etc.)

  In the conventional electromagnetic pump, during the suction, the inside of the diaphragm chamber 13 becomes a negative pressure, and the suction valve 17 is opened. For this reason, the fluid flows from the outside of the pump into the diaphragm chamber 13 through the suction hole 19, and the negative pressure acting on the suction valve side 12 a of the diaphragm 12 is remarkably reduced. On the other hand, the negative pressure acting on the discharge valve side 12b is not reduced because the discharge valve 18 is closed. As a result, the negative pressure generated in the diaphragm chamber 13 acts so as not to separate the discharge valve side 12 b of the diaphragm 12 from the discharge valve 18. The unbalance of the negative pressure generated between the suction valve side 12a and the discharge valve side 12b of the diaphragm 12 acts as a rotational force on the plunger 14, and the other end of the plunger 14 moves toward the discharge valve side. (The arrow direction in FIG. 4), the plunger 14 is inclined with respect to the sliding direction in the guide pipe 15.

Further, at the time of discharge, the fluid flows out from the discharge hole 20, but since the suction valve 17 is closed on the suction side, the suction valve side 12a of the diaphragm 12 becomes positive pressure, and the suction valve side 12a of the diaphragm 12 becomes positive. It acts to prevent movement in the direction of the intake valve. Thus, since the diaphragm 12 receives a force that the suction valve side 12a does not always approach the suction valve side, the inclination of the plunger 14 is not corrected.
Here, the line A in FIG. 4 is the original central axis of the plunger 14, and the line B indicates the central axis of the plunger 14 inclined.

In this way, when the plunger 14 remains tilted in the guide pipe 15 by driving the electromagnetic pump, a portion on the other end side of the plunger 14 and the guide pipe 15 on the discharge valve side (position C in FIG. 4). Then, there is a problem that the plunger 14 and the guide pipe 15 are always in contact with each other at a portion (position D in FIG. 4) on one end side of the plunger 14 and the guide pipe 15 and the load is concentrated. .
Thus, if there is a part where the plunger and the guide pipe always come into contact with each other and the load is concentrated, this part may be worn out and the life of the pump may be shortened.

  Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a solenoid and an electromagnetic pump that can extend the life by preventing the plunger from being inclined with respect to the sliding direction. .

That is, according to the solenoid according to the present invention, an excitation coil, a cylindrical guide pipe provided with a plunger insertion hole therein, provided inside the excitation coil, and a fixed yoke disposed around the excitation coil, A solenoid that includes a plunger that is slidably disposed in a plunger insertion hole of the guide pipe, is disposed with a gap between the fixed yoke, and forms a magnetic circuit with the fixed yoke. The center axis of the plunger insertion hole of the guide pipe is characterized in that it is deviated from the center axis with respect to the outer periphery of the guide pipe.
By adopting this configuration, the gap between the plunger and the fixed yoke on the displaced side becomes narrower than the gap between the displaced side and the fixed yoke on the opposite side. Accordingly, since the permeance between the plunger and the fixed yoke is larger on the displaced side than on the opposite side, the plunger always receives a force toward the displaced side. The permeance is the reciprocal of the magnetic resistance, and the larger the permeance, the more the magnetic flux in the magnetic circuit increases and the magnetic energy increases. For this reason, the plunger receives a large magnetic energy on the side where the plunger insertion hole is displaced, and receives a force toward the displaced side.

According to the electromagnetic pump of the present invention, an excitation coil, a cylindrical guide pipe provided inside the excitation coil and having a plunger insertion hole formed therein, a fixed yoke disposed around the excitation coil, and The plunger is slidably disposed in the plunger insertion hole of the guide pipe, and is disposed with a predetermined gap between the fixed yoke and a plunger that forms a magnetic circuit with the fixed yoke. In an electromagnetic pump comprising a diaphragm, a discharge valve that discharges fluid in the diaphragm chamber by reciprocating drive of the diaphragm, and a suction valve that sucks fluid into the diaphragm chamber by reciprocating drive of the diaphragm, the flow direction of fluid in the discharge valve The central axis of the plunger is arranged between a straight line connecting the axis of the pipe and the axis of the fluid flow direction in the intake valve, The permeance of the magnetic circuit between the fixed yoke and the plunger on either the outlet side or the suction valve side is greater than the permeance of the magnetic circuit between the other fixed yoke and the plunger. It is characterized by being provided.
By adopting this configuration, on one side where the permeance between the plunger and the fixed yoke is set to be large, a suction force that approaches the opposing surface of the fixed yoke acts on the plunger. The permeance is the reciprocal of the magnetic resistance, and the larger the permeance, the more the magnetic flux in the magnetic circuit increases and the magnetic energy increases. In this way, the plunger can be prevented from tilting by receiving a force directed to one side where the permeance of the magnetic circuit is set large.

Further, the central axis of the plunger insertion hole of the guide pipe is formed so as to be deviated to either the discharge valve side or the suction valve side from the central axis with respect to the outer periphery of the guide pipe. Also good.
According to such a configuration, the gap between the plunger and the fixed yoke is smaller on either the discharge valve side or the suction valve side than on the other side. That is, the permeance is proportional to the cross-sectional area of the magnetic path and inversely proportional to the size of the air gap (gap) formed in the magnetic path. Therefore, the permeance increases on the one side where the air gap is small, and the magnetic energy increases. . For this reason, the inclination of the plunger can be prevented by receiving the force toward the one side of the plunger.

According to the solenoid according to the present invention, since the inclination of the plunger with respect to the sliding direction can be prevented, the wear of the contact portion between the plunger and the guide pipe can be prevented, and the life can be extended.
According to the electromagnetic pump according to the present invention, since the plunger can receive a force directed toward the discharge valve side or the suction valve side, the inclination of the plunger with respect to the axial direction caused by the drive of the pump can be prevented. Thus, the wear of the contact portion between the plunger and the guide pipe can be prevented, and the life of the pump can be extended.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
Based on FIG. 1, it shows about the whole structure of an electromagnetic pump.
The electromagnetic pump 30 of the present embodiment is a type of positive displacement pump, and is a device that sucks and discharges fluid by reciprocating a diaphragm 32 in the diaphragm chamber 33 and changing the volume in the diaphragm chamber 33.

As a driving system of the diaphragm 32, a solenoid 34 is used.
Hereinafter, the configuration of the solenoid 34 will be described.
The solenoid 34 includes an exciting coil 35, a fixed yoke 36, and a plunger 38. The plunger 38 is housed and held in a plunger insertion hole 39 formed in the guide pipe 37. The guide pipe 37 is made of a nonmagnetic material, and is specifically made of synthetic resin.

The fixed yoke 36 is made of a magnetic material and is formed so as to cover the periphery of the exciting coil 35. Insulating members 40 are provided between both ends of the exciting coil 35 and the fixed yoke 36.
The fixed yoke 36 includes an upper yoke 36a disposed on one side of the exciting coil 35 and a lower yoke 36b disposed on the other side and connected to the upper yoke 36a.
In this embodiment, a part of the lower yoke 36b extends to one side as a side wall part 36c so as to cover the side surface of the coil, and the side wall part 36c is connected to the upper yoke 36a on one side.

The plunger 38 is a member made of a magnetic material. The plunger 38 has a small-diameter portion 42 that is a part accommodated in the guide pipe 37 and a large-diameter portion 44 provided at the other end of the small-diameter portion 42.
The outer diameter of the small diameter portion 42 is formed to be slightly smaller than the inner diameter of the guide pipe 37, and the plunger 38 is provided so as to slide well within the guide pipe 37.
The outer diameter of the large diameter portion 44 is formed larger than the inner diameter of the guide pipe 37, and the large diameter portion 44 is not housed in the guide pipe 37 and is located outside the guide pipe 37.

  The plunger 38 operates in the direction attracted by the magnetic energy generated by the exciting coil 35. The plunger 38 is moved in the protruding direction by a spring 47.

A first facing surface 51 is formed at the center of the upper yoke 36a so as to face the end surface 42a on one side of the small diameter portion 42 of the plunger 38. In the upper yoke 36a, a second facing surface 52 is formed on the inner wall surface of the extending portion that surrounds the first facing surface 51 and rises perpendicularly to the other direction with respect to the first facing surface 51. ing. The second facing surface 52 faces the outer peripheral surface 42 b in the vicinity of one end surface 42 a of the small diameter portion 42 of the plunger 38.
In the upper yoke 36 a, the first facing surface 51 and the second facing surface 52 form a magnetic path between the plunger 38.

The lower yoke 36 b includes a side wall portion 36 c that covers the side surface of the exciting coil 35 and an opposing surface portion 36 d that covers the other end of the exciting coil 35. The facing surface portion 36 d has a third facing surface 53 that faces the outer peripheral surface 44 b of the large diameter portion 44, and a fourth facing surface 54 that faces the end surface 44 a on one side of the large diameter portion 44.
The third facing surface 53 is formed on the inner wall surface of the extending portion that rises perpendicularly to the other direction with respect to the fourth facing surface 54.

  The second facing surface 52 and the third facing surface 53 are arranged with a slight gap so as not to contact the outer peripheral surface 42b of the small diameter portion 42 and the outer peripheral surface 44b of the large diameter portion 44 of the plunger 38, respectively. The

  An anti-vibration rubber 55 is attached to the facing surface portion 36d of the lower yoke 36b. When the plunger 38 moves to one side, the end surface 44a on one side of the large diameter portion 44 comes into contact with the anti-vibration rubber 55, thereby preventing vibration caused by the large diameter portion 44 coming into contact with the lower yoke 36b. can do.

  A support rod 56 connected to the center portion 32 a of the diaphragm 32 is provided at the center portion of the plunger 38 of the solenoid 34. The support rod 56 is provided so as to protrude from the solenoid 34 to one side, and is fixed to the center portion 32 a of the diaphragm 32.

  The plunger 38 is urged in the other direction by a spring 47. The spring 47 is disposed around the support rod 56 in the spring accommodating portion 58 formed inside the plunger 38, and between the other end surface of the spring accommodating portion 58 and the first opposing surface 51 of the upper yoke 36 a. It is provided to be compressed.

The plunger 38 acts in a direction in which it moves in one direction by a magnetic circuit formed by passing an exciting current through the exciting coil 35. When the exciting current flowing through the exciting coil 35 is turned off, the force generated by the magnetic circuit disappears, and the plunger 38 moves in the other direction by the biasing force of the spring 47.
The plunger 38 reciprocates by turning on and off the exciting current flowing to the exciting coil 35 in this way.

Next, the configuration on the pump side will be described.
A pump cover 60 is attached to one end of the solenoid 34, and the diaphragm 32 is provided in the pump cover 60. The diaphragm 32 is reciprocated by a solenoid 34, changes the volume in the diaphragm chamber 33, and sucks and discharges fluid.

  The diaphragm 32 is fixed between the upper yoke 36 a that is one end of the solenoid 34 and the pump cover 60, and forms a diaphragm chamber 33 between the inner wall surface of the pump cover 60.

  Side wall portions 36c of the lower yoke 36b are disposed on the outer peripheral surfaces of the pump cover 60 and the upper yoke 36a. A claw portion 61 is formed at the tip of the side wall portion 36c, and the claw portion 61 is bent along one end face of the pump cover 60 to sandwich the upper yoke 36a and the pump cover 60.

The pump cover 60 is provided with an intake valve that operates by reciprocating driving of the diaphragm 32 and a discharge valve. The suction valve and the discharge valve are provided inside two cylindrical portions 62 and 63 protruding from the pump cover 60 to one side.
A suction hole 64 that communicates between the diaphragm chamber 33 and the outside of the pump is formed in one of the cylindrical portions 62 and 63 of the pump cover 60. In the suction hole 64, a check ball 68 that contacts the inside of the outer opening 66 that is a part of the suction hole 64 that contacts the outside of the pump and closes the suction hole 64 is disposed. The check ball 68 corresponds to the intake valve.

  One end of a spring 69 is in contact with the check ball 68 and is urged so as to close the outer opening 66 by the urging force of the spring 69. The other end of the spring 69 is in contact with a retaining ring 70 that holds the other end of the spring 69. The retaining ring 70 is formed in a ring shape, and is formed with an inner opening 71 serving as a portion communicating with the diaphragm chamber 33 of the suction hole 64.

  A discharge hole 72 that communicates the diaphragm chamber 33 and the outside of the pump is formed in the other of the cylindrical portions 62 and 63 of the pump cover 60. In the discharge hole 72, a check ball 74 that contacts the outside of the inner opening 73 that is a part of the discharge hole 72 in contact with the diaphragm chamber 33 and closes the discharge hole 72 is disposed. The check ball 74 corresponds to the discharge valve.

  One end of a spring 76 is in contact with the check ball 74 and is urged so as to close the inner opening 73 by the urging force of the spring 76. The other end of the spring 76 is in contact with a retaining ring 78 that holds the other end of the spring 76. The retaining ring 78 is formed in a ring shape, and is formed with an outer opening 79 serving as a portion communicating with the outside of the pump of the discharge hole 72.

FIG. 2 shows a cross section of the guide pipe 37 and the positional relationship among the plunger 38, the suction valve 68, and the discharge valve 74 when viewed from the E direction (one side) in FIG.
A central axis V of the plunger 38 is a straight line G connecting an axis X in the fluid movement direction with respect to the suction valve 68 and an axis Y in the fluid movement direction of the discharge valve 74, and is between the axis X and the axis Y. Is arranged.

  The guide pipe 37 is formed such that the central axis V of the plunger insertion hole 39 (which coincides with the central axis V of the plunger 38) is biased toward the discharge valve 74 with respect to the central axis W of the outer periphery of the guide pipe 37. Has been. That is, the guide pipe 37 is formed so that the discharge valve 74 side is thinner than the suction valve 68 side.

Based on FIG. 3, the structure mentioned above about the case where it sees from a cross-sectional direction is further demonstrated.
The inner diameter of the second facing surface 52 of the upper yoke 36a is d1. If the outer diameter of the large-diameter portion 44 of the plunger 38 is d3, the center line of d1 and the center line of d3 are the same straight line.
However, since the plunger insertion hole 39 is deviated toward the discharge valve 74, when the outer diameter of the small diameter portion 42 of the plunger 38 is d2, the center line of d2 is more on the discharge valve 74 side than the center lines of d1 and d3. Is shifted in parallel by Δd.

For this reason, the plunger 38 has a smaller gap between the discharge valve 74 side and the second opposing surface 52 of the upper yoke 36a than the suction valve 68 side, and the third opposing surface 53 of the lower yoke 36b. It arrange | positions so that the space | gap between may become narrow.
Accordingly, a force F directed toward the discharge valve 74 acts on the plunger 38, and the inclination of the plunger 38 can be prevented.

In the above-described embodiment, the large diameter portion 44 is provided on the other end side of the plunger 38, and the third yoke for forming a magnetic path between the lower yoke 36 b and the outer peripheral surface 44 b of the large diameter portion 44. The configuration in which the opposite surface 53 is provided has been described.
However, the present invention is not limited to such a configuration, and the large diameter portion 44 may not be provided in the plunger 38. Even if the large diameter portion 44 is provided, the large diameter portion is provided in the lower yoke 36b. The 3rd opposing surface which opposes the outer peripheral surface 44b of 44 may not be provided.

In the electromagnetic pump of the above-described embodiment, in the permeance between the plunger and the fixed yoke, the gap between the plunger on the discharge valve side and the fixed yoke is set to be larger than the suction valve side. Adopted a configuration that is narrower than the intake valve side.
However, the permeance between the plunger of the electromagnetic pump and the fixed yoke is not limited to such a configuration in which the discharge valve side is made larger than the suction valve side. The discharge valve side may be wider than the suction valve side.

  Furthermore, the present invention is not limited to the case where the displacement direction of the plunger insertion hole 39 is directed toward the discharge valve 74 side. The plunger 38 is displaced toward the suction valve 68 side to displace the plunger 38 from the suction valve. The inclination of the plunger 38 can also be prevented by generating a force to be attracted to the 68 side.

  Since such an electromagnetic pump can prevent the wear of the plunger and extend its life, it is preferable to adopt it in a field where it is difficult to replace it once it is provided. For example, it can be favorably used in various applications such as a pump for supplying air and fuel for a fuel cell, a medical instrument, and a notebook PC for cooling.

  Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. .

It is sectional drawing of the electromagnetic pump concerning this invention. It is explanatory drawing which shows the case where the cross section of a guide pipe and the positional relationship of a plunger, a suction valve, and a discharge valve are seen from the E direction of FIG. It is sectional drawing of the electromagnetic pump which shows the mode of displacement of a plunger. It is sectional drawing which shows the mode at the time of inhalation of the conventional electromagnetic pump. It is sectional drawing which shows the mode at the time of discharge of the conventional electromagnetic pump.

Explanation of symbols

30 Electromagnetic pump 32 Diaphragm 32a Center part 33 Diaphragm chamber 34 Solenoid 35 Excitation coil 36 Fixed yoke 36a Upper yoke 36b Lower yoke 36c Side wall part 36d Opposing surface part 37 Guide pipe 38 Plunger 39 Plunger insertion hole 40 Insulating member 42 Small diameter part 42a One side End surface 42b outer peripheral surface 44 large diameter portion 44a one end surface 44b outer peripheral surface 47 spring 51 first opposing surface 52 second opposing surface 53 third opposing surface 54 fourth opposing surface 55 vibration isolating rubber 56 support rod 58 Spring housing part 60 Pump cover 61 Claw part 62, 63 Tubular part 64 Suction hole 66, 79 Outer opening part 68 Check ball (suction valve)
69, 76 Spring 70, 78 Retaining ring 71, 73 Inner opening 72 Discharge hole 74 Check ball (discharge valve)

Claims (3)

An exciting coil;
A cylindrical guide pipe provided inside the exciting coil and having a plunger insertion hole formed therein;
A fixed yoke arranged around the excitation coil;
In a solenoid comprising a plunger that is slidably disposed within a plunger insertion hole of a guide pipe, and is disposed with a gap between the fixed yoke and a plunger that forms a magnetic circuit with the fixed yoke,
The solenoid characterized in that the central axis of the plunger insertion hole of the guide pipe is formed deviating from the central axis with respect to the outer periphery of the guide pipe. An exciting coil;
A cylindrical guide pipe provided inside the exciting coil and having a plunger insertion hole formed therein;
A fixed yoke arranged around the excitation coil;
A plunger that is slidably disposed in a plunger insertion hole of the guide pipe, is disposed with a predetermined gap between the plunger and the fixed yoke, and forms a magnetic circuit with the fixed yoke;
A diaphragm to which a plunger is connected;
A discharge valve for discharging the fluid in the diaphragm chamber by reciprocating drive of the diaphragm;
In an electromagnetic pump comprising a suction valve for sucking fluid into a diaphragm chamber by reciprocating driving of the diaphragm,
The central axis of the plunger is disposed between a straight line connecting the axis of the fluid flow direction in the discharge valve and the axis of the fluid flow direction in the suction valve,
The permeance of the magnetic circuit between the fixed yoke and the plunger on either the discharge valve side or the suction valve side is larger than the permeance of the magnetic circuit between the other fixed yoke and the plunger. The electromagnetic pump characterized by being provided in.   The center axis of the plunger insertion hole of the guide pipe is formed so as to be deviated to either the discharge valve side or the suction valve side with respect to the center axis with respect to the outer periphery of the guide pipe. Item 3. The electromagnetic pump according to Item 2.

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