JP2011133071A - Self-holding solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-holding solenoid valve in which a fixed core and a permanent magnet are integrally moved to easily adjust the stroke of the movable core and the lateral attraction of the movable core is suppressed. <P>SOLUTION: A first contact part 41a and a second contact part 41c are formed on the fixed core 41 at both ends in the axial direction, and the first and second contact parts 41a, 41c are connected to each other through a small-diameter part 42. A recess 43 is formed in the fixed core 41 between the first contact part 41a and the second contact part 41c, and the permanent magnet 45 is disposed in the recess 43. While a coil 33a is not electrified, the small-diameter part 42 is magnetically saturated since part of the magnetic fluxes generated from the permanent magnet 45 passes therethrough. A magnetic circuit is maintained by the magnetic fluxes other than the magnetic fluxes passing through the small-diameter part 42. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a self-holding solenoid valve.

  For example, Patent Document 1 discloses a self-holding solenoid valve. As shown in FIG. 5, the self-holding solenoid valve 50 of Patent Document 1 includes a valve body 51 and a pressure fluid supply port 51 a and a pressure fluid discharge port that are spaced apart from one side surface of the valve body 51 at a predetermined interval. 51b and an exhaust port 51c are formed. In the valve body 51, a valve mechanism 60 that switches the communication state between the ports 51a to 51c is provided.

  A bottomed cylindrical bonnet 52 is integrally connected to one side surface of the valve body 51, and a bottomed cylindrical frame member 53 made of a magnetic material is fitted in the bonnet 52. . A cylindrical bobbin 54 around which a plurality of coils 54 a are wound is disposed inside the frame member 53, and a fixed iron core 55 is fixed inside the bobbin 54. A cylindrical guide ring 56 is fitted inside the frame member 53 and closer to the valve body 51 than the bobbin 54, and a movable iron core 57 is inserted into the guide ring 56. .

  The movable iron core 57 is urged in a direction away from the fixed iron core 55 under the action of the elastic force of the first spring member 58. One end of the first spring member 58 is engaged with the annular protrusion 57 a of the movable iron core 57, and the other end is provided so as to be engaged with the annular groove of the guide ring 56. The fixed iron core 55 and the movable iron core 57 are provided coaxially. An annular permanent magnet 59 is mounted between the bobbin 54 and the guide ring 56 so as to surround a part of the outer peripheral surface of the fixed iron core 55 and the movable iron core 57.

  In the self-holding solenoid valve 50 having the above-described configuration, when the coil 54a is energized by energizing the coil 54a, the exciting action and the attractive force of the permanent magnet 59 overcome the spring force of the first spring member 58 and the movable iron core 57. Is attracted and moved toward the fixed iron core 55, and the movable iron core 57 comes into contact with the fixed iron core 55. When the energization of the coil 54 a is stopped, the attractive force due to the exciting action of the coil 54 a disappears, but the attractive force of the permanent magnet 59 that attracts the movable iron core 57 to the fixed iron core 55 side is the spring force of the first spring member 58. Therefore, the state where the movable iron core 57 is attracted to the fixed iron core 55 is maintained.

JP 2002-188743 A

  However, in the self-holding electromagnetic valve 50 of Patent Document 1, the permanent magnet 59 is disposed so as to surround a part of the movable iron core 57 on the fixed iron core 55 side, thereby attracting the fixed iron core 55 and the movable iron core 57 to each other. Permanent magnets 59 are disposed around the surface. When the permanent magnet 59 is disposed around the attracting surface of the fixed iron core 55 and the movable iron core 57, the attractive force for attracting the movable iron core 57 toward the fixed iron core 55 is increased, but the movable iron core 57 is guided by the guide ring 56 in the permanent magnet 59. It tends to be adsorbed (laterally adsorbed) toward the side end face. Therefore, the self-holding solenoid valve 50 of Patent Document 1 requires means for smoothly moving the movable iron core 57 toward the fixed iron core 55 side by reducing the lateral adsorption of the movable iron core 57 by the permanent magnet 59 as much as possible. Thus, the configuration of the self-holding solenoid valve 50 becomes complicated.

  Therefore, in order to prevent the movable iron core 57 from being laterally attracted by the permanent magnet 59, it can be considered that the permanent magnet 59 is arranged along the moving direction of the movable iron core 57 with respect to the movable iron core 57. In this case, in order to suppress that the movable iron core 57 is directly attracted to the permanent magnet 59 and an impact is applied to the permanent magnet 59, as shown by a two-dot chain line in FIG. It is necessary to interpose the fixed iron core 55 between them. Therefore, in order to obtain a desired stroke length in the movable iron core 57 (for stroke adjustment), when the positions of the fixed iron core 55 and the permanent magnet 59 are to be adjusted, the fixed iron core 55 and the permanent magnet 59 are not moved separately. There was a problem that the stroke adjustment was troublesome.

  The present invention has been made paying attention to such problems existing in the prior art, and its purpose is to easily move the fixed iron core and the permanent magnet to adjust the stroke of the movable iron core. It is an object of the present invention to provide a self-holding electromagnetic valve that can be performed and that can suppress lateral adsorption of a movable iron core.

  In order to achieve the above object, the invention according to claim 1 is provided so that a cylindrical bobbin around which a coil is wound, a fixed iron core inserted into the bobbin, and coaxial with the fixed iron core. A self-holding electromagnetic valve comprising: a movable iron core; and a permanent magnet for self-holding the movable iron core by adsorbing the movable iron core when the coil is energized, Abutting portions are formed on both end sides, and both the abutting portions are connected by a connecting portion having a cross-sectional area smaller than the cross-sectional area of both abutting portions, and the permanent magnet is interposed between the abutting portions. The gist is that it is arranged.

The gist of the invention according to claim 2 is that, in the invention according to claim 1, the permanent magnet is disposed between the contact portions so as to surround the connecting portion.
The gist of the invention described in claim 3 is that, in the invention described in claim 1 or claim 2, the connecting part is connected by a small diameter part having a smaller diameter than both contact parts.

  The invention according to claim 4 is the gist of the invention according to claim 3, wherein the permanent magnet has a semi-cylindrical shape and two permanent magnets are disposed between the small diameter portions. To do.

  According to the present invention, the fixed iron core and the permanent magnet can be integrally moved to easily adjust the stroke of the movable iron core, and the horizontal adsorption of the movable iron core can be suppressed.

A longitudinal section showing a self-holding type electromagnetic valve in an embodiment. The perspective view which shows a fixed iron core and a permanent magnet. The longitudinal cross-sectional view of the solenoid part which shows the state by which it supplied with electricity to the coil and the coil was excited. The graph which shows the relationship between the cross-sectional area of a small diameter part, and suction force. The longitudinal cross-sectional view which shows the self-holding type | mold solenoid valve of a prior art example.

Hereinafter, an embodiment of a self-holding solenoid valve (hereinafter simply referred to as “solenoid valve”) embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the electromagnetic valve 10 includes a main valve portion 11 having a valve body 21 for switching an air flow path, and a solenoid portion 31 for driving the valve body 21.

First, the main valve part 11 will be described.
The main valve portion 11 includes a long box-shaped body 12 made of a non-magnetic material (made of a synthetic resin material), and a through-hole 12a is formed in the body 12 from one end to the other end in the longitudinal direction. ing. Further, on one side surface of the body 12, a supply port 13, an output port 14, and a discharge port 15 are formed in this order from one end of the body 12 in the longitudinal direction to the other end. It is opened toward the through hole 12a. Positive pressure air is supplied to the supply port 13 from a positive pressure supply source (not shown), and the output port 14 is connected to a pneumatic device (not shown) such as an air cylinder. The exhaust port 15 is connected to an exhaust pipe (not shown).

  One end of the through hole 12a is sealed by attaching a cylindrical retainer 17 with a bottom. The retainer 17 includes a bottom portion 17a that seals one end of the through hole 12a, and an extending portion 17b that extends in a cylindrical shape from the peripheral edge of the bottom portion 17a. The extending portion 17b is provided so that the tip thereof extends to the periphery of the opening in the output port 14 to the through hole 12a. In the extended portion 17b, a communication hole 17c is formed at a position overlapping with the supply port 13, and the supply port 13 and the retainer 17 communicate with each other via the communication hole 17c.

  Further, a supply valve seat 18 is formed at the distal end of the extending portion 17b so as to surround the through hole 12a. Further, in the body 12, a discharge valve seat 19 is formed on an end surface surrounding the through hole 12 a between the output port 14 and the discharge port 15 so as to face the supply valve seat 18. A valve chamber 20 is defined in a space located between the supply valve seat 18 and the discharge valve seat 19 and on the output port 14. A valve body 21 is accommodated in the valve chamber 20, and the valve body 21 can be brought into contact with and separated from the supply valve seat 18 and the discharge valve seat 19. Further, the retainer 17 and the valve chamber 20 communicate with each other.

  The valve body 21 is fitted on the outer peripheral surface of a cylindrical rod 22 inserted into the through hole 12 a and is provided integrally with the rod 22. A protruding portion 22 a that protrudes outward is formed on one end side of the rod 22, and one end side of the rod 22 is inserted into the retainer 17 so that the protruding portion 22 a is positioned in the retainer 17. A valve return spring 23 is interposed between the protrusion 22 a and the bottom 17 a of the retainer 17. The valve body 21 is biased in a direction away from the supply valve seat 18 by the spring force of the valve return spring 23.

  When the valve body 21 is moved away from the supply valve seat 18 by the spring force of the valve return spring 23, the valve body 21 is seated on the discharge valve seat 19, and the supply port 13 and the output port 14 are connected to the communication hole. 17c, the retainer 17 and the valve chamber 20 communicate with each other, and positive pressure air is supplied from the output port 14 to the pneumatic equipment. When the valve body 21 moves in a direction away from the discharge valve seat 19 against the spring force of the valve return spring 23, the valve body 21 is seated on the supply valve seat 18, and the output port 14, the discharge port 15, Are communicated via the valve chamber 20 and the through hole 12a, and the air discharged from the pneumatic device to the output port 14 is discharged from the discharge port 15.

Next, the solenoid unit 31 will be described.
The solenoid unit 31 includes a cylindrical magnetic cover 32 formed of a magnetic material, and one end of the magnetic cover 32 is joined to the other end of the body 12. An insertion hole 32 a is formed at the other end of the magnetic cover 32. Inside the magnetic cover 32, a cylindrical bobbin 33 around which a plurality of coils 33a are wound is disposed.

  A guide ring 34 is provided inside the magnetic cover 32 and closer to the body 12 than the bobbin 33, and the bobbin 33 and the guide ring 34 are provided between the other end inner surface of the magnetic cover 32 and the other end surface of the body 12. Is pinched. In the guide ring 34 and the bobbin 33, a movable iron core 35 made of a magnetic material and having a substantially cylindrical shape is inserted. One end side of the movable iron core 35 extends so as to enter the other end side of the through hole 12 a, and one end surface of the movable iron core 35 is in contact with the other end surface of the rod 22. In addition, a flange 35a protruding outward is formed at one end of the movable iron core 35, and an iron core return spring 36 is interposed between the guide ring 34 and the flange 35a. The movable iron core 35 is biased in the direction of pressing the rod 22 by the spring force of the iron core return spring 36.

  The bobbin 33 has a substantially cylindrical shape and a fixed iron core 41 made of a magnetic material. One end surface of the fixed iron core 41 is a magnetic pole surface, and this magnetic pole surface is disposed so as to face the other end surface of the movable iron core 35. Therefore, the movable iron core 35 and the fixed iron core 41 are arranged coaxially. As shown in FIGS. 1 and 2, near the other end of the fixed core 41 in the axial direction, a small diameter portion 42 is formed as a connecting portion having a smaller diameter than both ends of the fixed core 41 in the axial direction. The small-diameter portion 42 is circular when viewed in cross section and is formed to extend with the same diameter along the axial direction of the fixed iron core 41.

  In addition, a cylindrical first contact portion 41 a is formed on one end side of the fixed iron core 41 in the axial direction, and the first contact portion 41 a is formed to have a larger diameter than the small diameter portion 42. Further, a disc-shaped flange portion 41b is formed on the other end side of the fixed iron core 41, and the flange portion 41b is formed to have a larger diameter than the small diameter portion 42 and the first contact portion 41a. In addition, a second contact portion 41c having a larger diameter than the small diameter portion 42 and a smaller diameter than the flange portion 41b is formed between the flange portion 41b and the small diameter portion 42. The first and second contact portions 41 a and 41 c are connected by a small diameter portion 42. In the fixed iron core 41, the first contact portion 41a, the small diameter portion 42, and the second contact portion 41c are inserted into the bobbin 33. Further, an O-ring 46 as a fine adjustment means is interposed between the inner peripheral portion on the other end side of the bobbin 33 and the flange portion 41b.

  A concave portion 43 is formed at a position surrounded by the first contact portion 41a, the small diameter portion 42, and the second contact portion 41c near the other end in the axial direction of the fixed iron core 41. The recess 43 is formed so as to be recessed over the entire circumference of the fixed iron core 41 in the circumferential direction. Two semi-cylindrical permanent magnets 45 are disposed in the recess 43 of the fixed iron core 41. The radius of the arc on the inner surface of the permanent magnet 45 is slightly larger than the radius of the small diameter portion 42. For this reason, when the permanent magnet 45 is disposed in the recess 43, the inner surface of the permanent magnet 45 follows the peripheral surface of the small diameter portion 42. Further, in the state where the two permanent magnets 45 are disposed in the recess 43 and combined in a cylindrical shape, the outer diameter of the cylinder made of the two permanent magnets 45 is slightly smaller than the inner diameter of the bobbin 33.

  The two permanent magnets 45 are provided in the recess 43 so as to surround the small diameter portion 42. The length in the longitudinal direction of the permanent magnet 45 is slightly longer than the length of the recess 43 in the axial direction of the fixed iron core 41, that is, the length between the opposing surfaces of the first contact portion 41a and the second contact portion 41c. It is getting smaller. The permanent magnet 45 is disposed in the recess 43 without any gap formed between both end surfaces in the longitudinal direction of the permanent magnet 45 and the first contact portion 41a and the second contact portion 41c facing each end surface. It is installed.

  In a state where the permanent magnet 45 is disposed in the recess 43, the position of the fixed iron core 41 in the bobbin 33 is adjusted so that the stroke length of the movable iron core 35 becomes a desired stroke length. At this time, when the fixed iron core 41 is moved in the direction of pushing into the bobbin 33, the permanent magnet 45 comes into contact with the second contact portion 41 c, and the permanent magnet 45 together with the fixed iron core 41 is fixed by the inner peripheral surface of the bobbin 33. It moves so that it may be guided along the axial direction. On the other hand, when the fixed iron core 41 is moved in the direction in which it is extracted from the bobbin 33, the permanent magnet 45 comes into contact with the first contact portion 41 a, and the permanent magnet 45 together with the fixed iron core 41 is supported by the inner peripheral surface of the bobbin 33. Move to be guided along the direction.

  When the fixed iron core 41 moves to the movable iron core 35 side, a repulsive force that pushes back the fixed iron core 41 by the elastic force of the O-ring 46 is generated. Using the repulsive force of the O-ring 46, the position of the fixed iron core 41 is finely adjusted. Thereafter, the insertion hole 32a and the flange portion 41b are joined by laser welding. Therefore, the fixed iron core 41 is fixed to the magnetic cover 32 and the fixed iron core 41 is held in the bobbin 33. As a result, the permanent magnet 45 is arranged along the moving direction of the movable iron core 35 with respect to the movable iron core 35.

  Now, in the electromagnetic valve 10 having the above-described configuration, when the coil 33a is energized by energizing the coil 33a, as shown in FIG. 3, it passes through the fixed iron core 41, the guide ring 34, and the magnetic cover 32 around the coil 33a. A magnetic circuit L (two-dot chain line shown in FIG. 3) is formed. The exciting action of the coil 33 a and the attractive force of the permanent magnet 45 overcome the spring force of the iron core return spring 36, and the movable iron core 35 is attracted and moved toward the fixed iron core 41, so that the movable iron core 35 contacts the fixed iron core 41. It will be in contact. Then, the valve element 21 moves in a direction away from the supply valve seat 18 by the spring force of the valve return spring 23 and is seated on the discharge valve seat 19 so that the supply port 13 and the output port 14 communicate with each other.

  Here, the movable iron core 35 is attracted and moved to the fixed iron core 41 side, and the movable iron core 35 comes into contact with the fixed iron core 41, so that an impact is transmitted to the fixed iron core 41, and the shock transmitted to the fixed iron core 41 is the permanent magnet 45. Try to be communicated to. However, in the present embodiment, since the fixed iron core 41 is provided with the small diameter portion 42, an impact to be transmitted to the permanent magnet 45 is transmitted to the small diameter portion 42, and the flange portion 41 b and the magnetic cover are further transmitted from the small diameter portion 42. 32. For this reason, the impact transmitted to the permanent magnet 45 from the fixed iron core 41 is relieved.

  On the other hand, when the energization to the coil 33a is stopped, the attractive force due to the exciting action of the coil 33a disappears. At this time, the permanent magnet 45 is disposed so as to sandwich the small diameter portion 42. A part of the magnetic flux generated from the two permanent magnets 45 passes and is magnetically saturated. Therefore, the magnetic circuit L is maintained by a magnetic flux other than the magnetic flux passing through the small diameter portion 42, and the state where the movable iron core 35 is attracted to the fixed iron core 41 is maintained by the magnetic circuit L.

  Here, as shown in the graph of FIG. 4, the smaller the cross-sectional area of the small-diameter portion 42, the more easily the magnetic saturation is caused by the magnetic flux of the permanent magnet 45. The suction force sucked toward the fixed iron core 41 increases. That is, the diameter of the small diameter portion 42 in the present embodiment is such that the magnetic circuit L can be maintained while the small diameter portion 42 is saturated by the magnetic flux of the permanent magnet 45, and the movable iron core 35 contacts the fixed iron core 41. The diameter is set so that the small diameter portion 42 can sufficiently withstand the impact.

  Next, when the current polarity is reversed in the forward and reverse directions and the coil 33a is energized, the magnetic flux generated from the coil 33a acts in a direction to cancel the magnetic circuit L, and the attractive force for attracting the movable iron core 35 toward the fixed iron core 41 is small. Become. Then, the movable iron core 35 tries to return to the original position by the spring force of the iron core return spring 36, and the pressing force with which the movable iron core 35 presses the rod 22 resists the spring force of the valve return spring 23. The valve body 21 is pressed by 35 and moves away from the discharge valve seat 19. Then, the valve body 21 is seated on the supply valve seat 18 so that the output port 14 and the discharge port 15 communicate with each other.

In the above embodiment, the following effects can be obtained.
(1) A first contact portion 41a and a second contact portion 41c are formed on both ends of the fixed iron core 41 in the axial direction, and the first and second contact portions 41a and 41c are separated by a small diameter portion 42. It is connected. In the fixed iron core 41, a recess 43 is formed between the first contact portion 41 a and the second contact portion 41 c, and a permanent magnet 45 is disposed in the recess 43. Therefore, by inserting the fixed iron core 41 into the bobbin 33 with the permanent magnet 45 disposed in the recess 43, the permanent magnet 45 follows the moving direction of the movable iron core 35 with respect to the movable iron core 35. It is arrange | positioned and the horizontal adsorption | suction of the movable iron core 35 can be suppressed. Further, when the fixed iron core 41 is moved in the bobbin 33, the permanent magnet 45 comes into contact with the first contact portion 41 a or the second contact portion 41 c and moves together with the fixed iron core 41. Therefore, when adjusting the position of the fixed iron core 41 in the bobbin 33 for adjusting the stroke of the movable iron core 35, the fixed iron core 41 and the permanent magnet 45 can be moved integrally, and the stroke of the movable iron core 35 can be adjusted. Adjustment can be performed easily. In a state where the coil 33 a is not energized, the small diameter portion 42 is magnetically saturated by passing a part of the magnetic flux generated from the permanent magnet 45, and the magnetic circuit is caused by magnetic flux other than the magnetic flux passing through the small diameter portion 42. L is maintained. Therefore, even if the small-diameter portion 42 is formed so that the fixed iron core 41 and the permanent magnet 45 can move integrally, the magnetic circuit L is formed between the movable iron core 35 and the fixed iron core 41. The magnetic circuit L for maintaining the state where the iron core 35 is attracted to the fixed iron core 41 is not adversely affected.

  (2) The permanent magnet 45 is disposed so as to surround the small diameter portion 42. Therefore, as compared with the case where the permanent magnet 45 is partially disposed around the small-diameter portion 42 without surrounding the small-diameter portion 42, the small-diameter portion 42 can be efficiently magnetically saturated and the magnetic circuit L Magnetic flux density can be increased.

  (3) The permanent magnet 45 has a semi-cylindrical shape, and two permanent magnets 45 are disposed in the recess 43. Therefore, for example, compared with the case where the permanent magnets divided into three or more are disposed in the recess 43, the two permanent magnets 45 can be combined in a cylindrical shape by simply disposing in the recess 43, As a result, the permanent magnet 45 can be easily disposed so as to surround the small diameter portion 42.

  (4) The diameter of the small diameter portion 42 can be saturated when the small diameter portion 42 is saturated by the magnetic flux of the permanent magnet 45 and the movable iron core 35 is attracted to the fixed iron core 41 and the movable iron core 35 contacts the fixed iron core 41. The diameter is set so that the small-diameter portion 42 can withstand this impact. Therefore, in the small diameter portion 42, it is possible to generate an attractive force that attracts the movable iron core 35 toward the fixed iron core 41, and the small diameter portion 42 can mitigate the impact transmitted to the permanent magnet 45.

  (5) The permanent magnet 45 is provided integrally with the fixed iron core 41 by being disposed in the recess 43 of the fixed iron core 41. Therefore, when assembling the solenoid valve 10, the fixed iron core 41 and the permanent magnet 45 can be handled as one part, and the fixed iron core is divided into two parts and assembled so that the permanent magnet is sandwiched between the two fixed iron cores. Compared to the case, the assembly work of the electromagnetic valve 10 can be easily performed.

  (6) In the electromagnetic valve 10 having the above configuration, the position of the fixed iron core 41 in the bobbin 33 can be finely adjusted using the elastic force of the O-ring 46. Therefore, the position in the bobbin 33 in the fixed iron core 41 can be finely adjusted, and the desired stroke length in the movable iron core 35 can be obtained more accurately.

In addition, you may change the said embodiment as follows.
In the embodiment, the permanent magnet 45 has a semi-cylindrical shape, and the two permanent magnets 45 are disposed in the recess 43. However, the present invention is not limited to this. You may arrange | position around.

  In the embodiment, the permanent magnet 45 is disposed so as to surround the small-diameter portion 42. However, the present invention is not limited to this. For example, the permanent magnet 45 is partially permanent around the small-diameter portion 42 without surrounding the small-diameter portion 42. A magnet 45 may be arranged.

  In the embodiment, the first and second contact portions 41a and 41c are connected to each other by the small-diameter portion 42 having a circular shape in cross section. However, the present invention is not limited thereto. And the 2nd contact parts 41a and 41c may be connected.

  In the embodiment, a gap may be formed between both longitudinal end surfaces of the permanent magnet 45 and the first contact portion 41a and the second contact portion 41c facing each end surface. According to this, compared with the case where a gap is not formed between both end surfaces in the longitudinal direction of the permanent magnet 45 and the first contact portion 41a and the second contact portion 41c facing each end surface, the concave portions are formed. The operation of disposing the permanent magnet 45 on 43 and the operation of removing the permanent magnet 45 from the recess 43 are facilitated.

  In the embodiment, the flange 41b may not be provided at the other end of the fixed iron core 41, and only the second contact part 41c may be provided, and the second contact part 41c and the insertion hole 32a may be welded. That is, both ends of the fixed iron core 41 may be formed with the same diameter.

  In the embodiment, the O-ring 46 is interposed as a fine adjustment means between the inner peripheral portion on the other end side of the bobbin 33 and the flange portion 41b. However, the present invention is not limited to this. A body may be interposed.

  In the embodiment, by utilizing the elastic force of the O-ring 46 between the inner peripheral portion on the other end side of the bobbin 33 and the flange portion 41b, the O-ring 46 functions as fine adjustment means. Not limited to. For example, by forming a female screw in the insertion hole 32a and a male screw on the peripheral surface of the flange portion 41b, the flange portion 41b is screwed back and forth with respect to the insertion hole 32a, so that the position of the fixed iron core 41 in the bobbin 33 is increased. May be finely adjustable. In this case, the fine adjustment means is constituted by the internal thread formed in the insertion hole 32a and the external thread formed in the flange portion 41b.

In the embodiment, the O-ring 46 may not be provided between the inner peripheral portion on the other end side of the bobbin 33 and the flange portion 41b.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

  (A) The self-holding electromagnetic according to any one of claims 1 to 4, wherein fine adjustment means capable of fine adjustment of the position of the fixed iron core in the bobbin is provided. valve.

  (B) One end surface of the fixed iron core is a magnetic pole surface facing the movable iron core, and a flange portion protruding outward is formed at the other end of the fixed iron core, and the flange portion and the bobbin The self-holding solenoid valve according to the technical idea (a), wherein the fine adjustment means is provided between them.

  (C) A gap is provided between the permanent magnet and the contact portion, and any one of the technical ideas (A) and (B) The self-holding solenoid valve according to item.

  L ... Magnetic circuit, 10 ... Self-holding solenoid valve, 33 ... Bobbin, 33a ... Coil, 35 ... Movable iron core, 41 ... Fixed iron core, 41a ... First contact portion, 41b ... Flange portion, 41c ... Second contact , 42... Small diameter portion as a connecting portion, 45. Permanent magnet, 46. O-ring as fine adjustment means.

Claims (4)

A cylindrical bobbin around which a coil is wound;
A fixed iron core inserted into the bobbin;
A movable iron core disposed coaxially with the fixed iron core;
A permanent magnet for self-holding the movable iron core by adsorbing the movable iron core when energizing the coil, and a self-holding solenoid valve,
Abutting portions are formed on both ends of the fixed iron core in the axial direction, and both the abutting portions are connected by a connecting portion having a cross-sectional area smaller than the cross-sectional area of both the abutting portions, and the permanent magnet is A self-holding solenoid valve, which is disposed between the contact portions.   The self-holding solenoid valve according to claim 1, wherein the permanent magnet is disposed between the contact portions so as to surround the connecting portion.   The self-holding solenoid valve according to claim 1 or 2, wherein the connecting portion is connected by a small diameter portion having a smaller diameter than both contact portions.   4. The self-holding solenoid valve according to claim 3, wherein the permanent magnet has a semi-cylindrical shape, and two permanent magnets are disposed between the small diameter portions.

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