Self-holding solenoid device

Abstract

To provide a self-holding solenoid device with few restrictions on the shapes of the movable iron core and fixed iron core.SOLUTION: A self-holding solenoid device 1 moves a movable iron core 3 between two stop positions, the movable iron core 3 includes a shaft portion 31 protruding in the axial direction, a shaft hole 4b through which a shaft portion 31 is inserted is formed in a fixed iron core 4, and a permanent magnet 7 that attracts a magnetic body 61b is disposed on the shaft portion 31 that is inserted into the internal space S of the fixed iron core 4 via the shaft hole 4b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a self-holding solenoid device that operates various devices using a movable iron core. [Background technology]

[0002] Solenoid devices are used in a variety of industrial fields as a means for operating various devices such as valves and machines. A solenoid device operates various devices by driving a reciprocating movable iron core through magnetic action when current is passed through a coil.

[0003] Generally, a solenoid device comprises a coil, a fixed iron core, and a movable iron core. When current is passed through the coil, a magnetic force is generated between the fixed iron core and the movable iron core, driving the movable iron core in a direction toward the fixed iron core.

[0004] The solenoid device disclosed in Patent Document 1 has a permanent magnet fixed to the surface of the movable core facing the fixed core, and when current is passed through the coil and the movable core approaches the fixed core, the magnetic force of the permanent magnet attracts the movable core in a direction toward the fixed core, thereby reducing the amount of current passed through the coil. Furthermore, this permanent magnet has a so-called self-holding function, which maintains the movable core attracted to the fixed core by its magnetic force when the movable core is stopped in a position where it is close to the fixed core, thereby eliminating the need for current to be passed through this period. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-154312 A (pages 4 to 5, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] The solenoid device of Patent Document 1 is configured so that the opposing portions of the movable iron core and the fixed iron core are nested in order to efficiently use the magnetic flux density between them. However, because a permanent magnet is provided between the movable iron core and the fixed iron core, there is a problem in that there are many restrictions on the nested shape.

[0007] The present invention has been made in view of these problems, and has as its object to provide a self-holding solenoid device in which there are few restrictions on the shapes of the movable iron core and the fixed iron core. [Means for solving the problem]

[0008] In order to solve the above problems, the self-holding solenoid device of the present invention comprises: A self-holding solenoid device comprising a coil, a movable iron core, a fixed iron core, and a permanent magnet, the self-holding solenoid device moving the movable iron core between two stop positions, The movable core has a shaft portion that protrudes in the axial direction, The fixed core has a shaft hole through which the shaft portion is inserted, The permanent magnet is disposed on the shaft portion that is inserted into the internal space of the fixed iron core via the shaft hole, and is attracted to the magnetic body. According to this, by disposing the permanent magnet in the internal space of the fixed iron core, it is possible to provide a self-holding solenoid device with few restrictions on the shapes of the movable iron core and the fixed iron core.

[0009] The magnetic body may be part of a cover that closes the internal space of the stationary core. This makes it possible to easily form a magnetic body that is attracted to the permanent magnet placed in the internal space of the fixed iron core.

[0010] The magnetic body may be a protrusion that protrudes from the cover. This allows the stroke amount of the movable core to be adjusted by the amount of protrusion of the convex portion.

[0011] The permanent magnet may be attracted to the fixed iron core at a stop position where the movable iron core is spaced apart from the fixed iron core. This not only makes it possible to self-hold the movable iron core at the two stop positions of the movable iron core, but also makes it possible to reduce the size of the solenoid device since it is configured with one permanent magnet.

[0012] a spring is provided in the internal space of the fixed iron core to bias the movable iron core in a direction away from the fixed iron core; The spring may be inserted into the protrusion. This allows the protrusion to suppress the deflection of the spring, thereby improving the linearity of the movable core.

[0013] The spring may be disposed so as to fit over the protrusion. This allows the protrusion to further suppress the bending of the spring, thereby further improving the linearity of the movable core. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing a state in which the plunger is driven to a stop position (first position) away from the center post and is self-held by a permanent magnet in the self-holding solenoid device of the first embodiment according to the present invention. [Figure 2] 4 is a cross-sectional view showing a state in which the plunger is driven to a stop position (second position) close to the center post and is self-held by the permanent magnet in the self-holding solenoid device of the first embodiment. FIG. [Figure 3] FIG. 1(a) is a diagram showing the magnetic field lines of the permanent magnet when the plunger is in the first position, and FIG. 1(b) is a diagram showing the magnetic field lines of the permanent magnet when the plunger is in the second position. [Figure 4] 10(a) and 10(b) are diagrams illustrating how the plunger moves from a state in which it is located at a first position to a state in which it is self-retained in the first embodiment. [Figure 5]10(a) and 10(b) are diagrams illustrating how the plunger moves from the second position to the first position and is self-retained in the first embodiment. [Figure 6] 10A and 10B are diagrams showing modified examples of the protrusion of the cover into which the spring is inserted; [Figure 7] 10A and 10B are diagrams showing modified examples of retainers that support permanent magnets. [Figure 8] 10A and 10B are diagrams illustrating modified examples of permanent magnets. [Figure 9] FIG. 6 is a cross-sectional view of a self-holding solenoid device according to a second embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view of a self-holding solenoid device according to a third embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional view of a self-holding solenoid device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A self-holding solenoid device according to the present invention will be described below with reference to an embodiment. [Example]

[0016] A self-holding solenoid device (hereinafter, sometimes simply referred to as a "solenoid device") according to a first embodiment will be described with reference to Figures 1 to 5. In the following description, the left and right indicated by the arrows in Figure 1 will be referred to as the left and right of the solenoid device.

[0017] 1 and 2, the solenoid device 1 is mainly composed of a solenoid molded body 2 equipped with a coil 20, a plunger 3, a center post 4, a return spring 5, a solenoid case 6, and a self-holding permanent magnet 7. The plunger 3 is the movable core of the present invention, while the center post 4, the solenoid case 6, and a lower plate 8 (described later) are the fixed core of the present invention.

[0018] The solenoid compact 2 is made of a non-magnetic material such as resin, and is mainly composed of a bobbin portion 21 and a cap portion 24. The solenoid compact 2 also has an annular lower plate 8 made of a magnetic material such as iron, which is integrally provided between the bobbin portion 21 and the cap portion 24. The solenoid compact 2 also has a recess 2a into which the plunger 3 and the center post 4 can be inserted.

[0019] A coil 20 is formed by winding a conductor 22 around the outer periphery of the bobbin portion 21. An end of the conductor 22 is connected to a lead wire 23, and when power is supplied from a power source (not shown), the coil 20 generates a magnetic flux.

[0020] The cap portion 24 is configured to close an opening 60b formed on the axial right side of the case body 60 by abutting axially against an inner wall on the axial right side of the case body 60 when the solenoid molded body 2 is inserted through the solenoid case 6, more specifically, through an opening 60a formed on the axial left side of the case body 60, which will be described later. The cap portion 24 also has a shaft hole 24a that penetrates axially through the center in the radial direction. A rod 31 serving as a shaft portion, which will be described later, is inserted through the shaft hole 24a, and the rod 31 is journaled by a bearing 25 provided on the inner peripheral surface of the shaft hole 24a.

[0021] The plunger 3 is mainly composed of a plunger body 30 having an approximately cylindrical shape and made of a magnetic material such as iron, and a rod 31 made of a non-magnetic material such as an aluminum alloy and protruding axially from the plunger body 30.

[0022] The plunger body 30 is disposed in the recess 2a of the solenoid molded body 2. A minute gap is formed between the outer peripheral surface of the plunger body 30 and the inner peripheral surface of the recess 2a by being slightly separated in the radial direction, and the plunger body 30 can move smoothly relative to the solenoid molded body 2 in the axial direction.

[0023] The plunger body 30 has a through-hole 30a formed in the radial center thereof, penetrating in the axial direction. A base 31a of a rod 31 is inserted into the through-hole 30a and is fixed integrally thereto by welding, press-fitting, or the like. That is, the plunger body 30 and the rod 31 are both movable in the axial direction. The right axial end of the rod 31 is connected to a load such as an on-off valve (not shown).

[0024] A flat surface 30b and an annular suction portion 30c are formed at the left axial end of the plunger body 30. The flat surface 30b extends radially from the outer diameter side of the through hole 30a of the plunger body 30 and faces a flat surface 40b of the center post 4, which will be described later. The suction portion 30c protrudes axially left from the outer diameter side of the flat surface 30b, and its inner circumferential surface is formed in a tapered shape.

[0025] The rod 31 has a base 31a and an attachment portion 31b formed on the tip side of the rod 31, i.e., on the left end in the axial direction of the base 31a. The attachment portion 31b is formed to have a smaller diameter than the base 31a, and a flanged retainer 32 made of a magnetic material such as iron is fitted onto the attachment portion 31b. The retainer 32 abuts in the axial direction against a step 31c formed between the base 31a and the attachment portion 31b of the rod 31, thereby restricting movement of the retainer 32 to the right in the axial direction.

[0026] The permanent magnet 7 is annular and has a through hole 70 formed with a diameter slightly larger than or equal to the outer diameter of the cylindrical portion 32a of the retainer 32 (see FIGS. 1 and 2). With the cylindrical portion 32a of the retainer 32 inserted into the through hole 70, the end face of the permanent magnet 7 on the right side in the axial direction is magnetically attached to the flange portion 32b of the retainer 32. In this embodiment, the permanent magnet 7 has an N pole on the left side in the axial direction and an S pole on the right side in the axial direction, but this is not limiting and the permanent magnet 7 may have an S pole on the left side in the axial direction and an N pole on the right side in the axial direction.

[0027] Additionally, a thin, annular snap ring 33 made of a magnetic material such as iron and having a diameter smaller than that of the permanent magnet 7 and a single cut surface in the radial direction is fixed to the left of the permanent magnet 7 in the axial direction. More specifically, the snap ring 33 is fitted into an annular groove 31d recessed in the inner radial direction in the outer peripheral surface of the mounting portion 31b of the rod 31, and the left axial end face of the permanent magnet 7 abuts against the right axial end face of the snap ring 33 in the axial direction, thereby preventing the permanent magnet 7 and the retainer 32 from slipping out to the left in the axial direction. That is, in this embodiment, the permanent magnet 7 is axially sandwiched between the flange portion 32b of the retainer 32 and the snap ring 33 at the mounting portion 31b of the rod 31. The snap ring may be C-shaped.

[0028] The center post 4 is made of a magnetic material such as iron and has a cylindrical portion 40 and a flange portion 41 that extends radially outward from the left axial end of the cylindrical portion 40. The center post 4 also has a recess 4a into which a return spring 5 is inserted.

[0029] The center post 4 is inserted into the recess 2a of the solenoid molded body 2 from the left side in the axial direction. At this time, the right side surface of the flange portion 41 in the axial direction abuts against the left end surface of the solenoid molded body 2 in the axial direction. In other words, the degree of insertion of the center post 4 into the solenoid molded body 2 can be determined by the abutment with the flange portion 41. This makes the solenoid device 1 easy to assemble.

[0030] The center post 4 also has a shaft hole 4b that penetrates the center in the axial direction at the radial center of the right end in the axial direction. A base 31a of a rod 31 is inserted into the shaft hole 4b, and the rod 31 is journaled by a bearing 42 that is provided on the inner circumferential surface of the shaft hole 4b.

[0031] A truncated cone-shaped attraction portion 40c is formed at the right axial end of the cylindrical portion 40 of the center post 4, with its right end face forming a flat surface 40b. The flat surface 40b extends radially from the outer diameter side of the axial hole 4b of the center post 4 and faces the flat surface 30b of the plunger body 30 described above. The attraction portion 40c has a tapered outer circumferential surface.

[0032] In this manner, in this embodiment, a nested shape is formed between the plunger 3 and the center post 4 by the attraction portions 30c and 40c, and the magnetic flux density is optimized.

[0033] The spring 5 inserted into the recess 4a of the center post 4 is a compression spring, and its right axial end abuts against the left axial end face of the permanent magnet 7, and its left axial end abuts against the bottom surface of the recess 61a of the cover 61 that constitutes the solenoid case 6 described later.

[0034] The solenoid case 6 is composed of a substantially cylindrical case body 60 made of a magnetic material such as iron, and a cover 61 made of a magnetic material such as iron.

[0035] The case body 60 has an opening 60a formed on its left axial side and an opening 60b formed on its right axial side. The case body 60 also has a step 60c on the inner diameter side of the left axial end.

[0036] The cover 61 has a recess 61a on its axially right end face, into which the flange portion 41 of the center post 4 can be inserted. The cover 61 also has a cylindrical protrusion 61b, which is a magnetic body and extends axially right from the radial center of the recess 61a. A recess 61c, which is recessed axially left, is formed in the radial center on the axially right end face of the protrusion 61b. In this embodiment, a spring 5 is fitted onto the outside of the protrusion 61b.

[0037] Here, an example of the assembly procedure for the solenoid device 1 will be described. First, the solenoid molded body 2 is inserted into the opening 60a of the case body 60 from the axial left side. Next, the plunger 3 and center post 4, in an assembled state, are inserted into the recessed portion 2a of the solenoid molded body 2 from the axial left side. Next, the spring 5 is inserted into the recessed portion 4a of the center post 4 from the axial left side with the spring 5 fitted onto the protruding portion 61b of the cover 61, and the flange portion 41 of the center post 4 is inserted into the recessed portion 61a of the cover 61. Finally, the left axial end of the case body 60 is crimped to the chamfered portion on the outer periphery of the cover 61. At this time, the stepped portion 60c of the case body 60 functions as a load-receiving portion that receives the axial load during crimping.

[0038] In this manner, in this embodiment, the internal space S of the center post 4 is closed by inserting the flange portion 41 of the center post 4 into the recess 61a of the cover 61. The internal space S of the center post 4 is defined by the recess 4a of the center post 4 and the end face of the cover 61 on the right side in the axial direction.

[0039] Next, the self-retaining function of the permanent magnet 7 disposed in the internal space S of the center post 4 will be described with reference to FIG.

[0040] As shown in Figure 3(a), when the plunger 3, more specifically the plunger body 30, is positioned at a stop position (hereinafter sometimes referred to as the "first position") away from the center post 4 (see Figure 1), the magnetic field lines M from the permanent magnet 7 are mostly guided to the inner surface of the center post 4, which is a magnetic body located close to the left end face in the axial direction, as shown by the solid arrows, and the permanent magnet 7 and the center post 4 attract each other, thereby self-holding the plunger 3.

[0041] On the other hand, as shown in Figure 3(b), when the plunger body 30 is positioned in a stop position (hereinafter sometimes referred to as the "second position") close to the center post 4 (see Figure 2), the magnetic field lines M from the permanent magnet 7 are mostly guided to the convex portion 61b of the cover 61, which is a magnetic body located close to the left end face in the axial direction, as shown by the solid arrow, and the permanent magnet 7 and the convex portion 61b of the cover 61 attract each other, thereby self-holding the plunger 3.

[0042] Next, the operation of the solenoid device 1 will be described.

[0043] The solenoid device 1 of this embodiment can move the plunger 3 between two stop positions, a first position on the right side of the axial direction (see Figure 1) and a second position on the left side of the axial direction (see Figure 2), by magnetic action by switching the direction of current flow to the coil 20.

[0044] First, a state in which the plunger 3 is in the first position and in a non-energized state will be described. As shown in FIG. 1, the solenoid device 1 operates in such a manner that the plunger 3 is biased by the biasing force (F sp ), the plunger 3 is pressed axially rightward by the retainer 32. This causes the axially right end face of the flange portion 32b of the retainer 32 attached to the mounting portion 31b of the rod 31 to abut against the bottom surface of the recess 4a of the center post 4, maintaining the plunger 3 in a stopped state at the first position. Furthermore, as described above, when the plunger 3 is in the first position, the magnetic field lines M (see FIG. 3(a)) of the permanent magnet 7 arranged in the internal space S of the center post 4 act on the center post 4, and the permanent magnet 7 and the center post 4 attract each other, thereby self-retaining the plunger 3.

[0045] At this time, the plunger 3 is subjected to the biasing force (F sp ) is acting on the permanent magnet 7. M ) acts on the center post 4. Therefore, the force F acts on the plunger 3, with the right axial direction being positive. plu1 =F sp +F Mis at work.

[0046] As shown in FIG. 4(a), when the plunger 3 is in the first position, the solenoid device 1 starts to be energized and a current is applied to the coil 20, which generates an electromagnetic force (F sol1 ) is generated. This electromagnetic force (F sol1 ) is the biasing force of spring 5 (F sp ) and the attractive force (F M ) exceeds the sum of (F sol1 >F sp +F M ), the plunger 3 is attracted toward the center post 4. That is, the plunger 3 begins to move axially to the left.

[0047] When the plunger 3 moves axially to the left and the permanent magnet 7 attached to the mounting portion 31b of the rod 31 approaches the protrusion 61b of the cover 61, the magnetic field lines M of the permanent magnet 7 suddenly act on the protrusion 61b of the cover 61.

[0048] At this time, since the magnetic field lines M of the permanent magnet 7 and the magnetic field lines EM generated by applying a current to the coil 20 are oriented in the same direction, the attractive force (F M ) is strengthened, the plunger 3 can be reliably and quickly moved to the second position in a state where the plunger 3 is close to the center post 4, and the amount of current flow can be reduced.

[0049] Finally, with the tip of the mounting portion 31b of the rod 31 inserted into the recess 61c formed in the protrusion 61b of the cover 61, the retaining ring 33 moves until it abuts against the end face of the protrusion 61b on the right side in the axial direction, and the plunger 3 is positioned in the second position (see Figure 2).

[0050] Furthermore, even if the current supply to the coil 20 is stopped and the coil 20 is in a non-energized state, as described above, the magnetic field lines M (see FIG. 3(b)) of the permanent magnet 7 arranged in the internal space S of the center post 4 act on the protrusion 61b of the cover 61, and the permanent magnet 7 and the protrusion 61b of the cover 61 attract each other, thereby self-holding the plunger 3 (see FIG. 4(b)). At this time, the force F acts on the plunger 3, with the right axial direction being positive. plu2 =F sp -F M is acting (however, F M >F sp ).

[0051] When the plunger 3 is in the second position, the left axial end face of the permanent magnet 7 is slightly spaced apart from the right axial end face of the protrusion 61b. When the plunger 3 is in the second position, the plunger body 30 and the center post 4, which are nested at their opposing positions, are slightly spaced apart from each other in the axial direction.

[0052] In this way, the retaining ring 33 attached to the attachment portion 31b of the rod 31 prevents the permanent magnet 7 from colliding with the protrusion 61b of the cover 61, and the plunger body 30 from colliding with the center post 4.

[0053] Next, when the self-holding function is released in a state where the plunger 3 is located at the second position, a reverse current is applied to the coil 20, and an electromagnetic force (F sol2 At this time, the current applied to the coil 20 generates the attractive force (F M ) and the electromagnetic force (F sol2 ) is generated by the application of a reverse current to the coil 20. In other words, the magnetic field lines M of the permanent magnet 7 and the magnetic field lines EM generated by the application of a reverse current to the coil 20 are in opposite directions, and the magnetic forces cancel each other out. sp) presses the plunger 3 to the right in the axial direction, causing the plunger 3 to move away from the protrusion 61b of the cover 61.

[0054] Finally, the biasing force of the spring 5 (F sp ) alone can move the plunger 3 axially to the right and return it to the first position (see FIG. 5(b)). Therefore, the application of the reverse current to the coil 20 can be done for a short period of time.

[0055] When the plunger 3 returns to the first position, the axial right end face of the flange portion 32b of the retainer 32 attached to the mounting portion 31b of the rod 31 abuts against the bottom surface of the recess 4a of the center post 4, thereby preventing a collision between the permanent magnet 7 and the center post 4.

[0056] As described above, in the solenoid device 1 of this embodiment, the plunger 3 has the rod 31 protruding in the axial direction, the center post 4 is formed with an axial hole 4b through which the rod 31 is inserted, and a magnetic body, i.e., a permanent magnet 7 that is attracted to the center post 4 in the first position and to the protrusion 61b of the cover 61 in the second position, is disposed on the mounting portion 31b of the rod 31 that is inserted into the internal space S of the center post 4 via the axial hole 4b. In this way, by disposing the permanent magnet 7 in the internal space S of the center post 4, there are fewer restrictions on the shapes of the movable iron core and the fixed iron core, more specifically, on the nested shape at the opposing portion of the plunger body 30 and the center post 4, making it possible to optimize the magnetic flux density.

[0057] Furthermore, the plunger 3 is self-held at each of the two stop positions by the magnetic body and the permanent magnet 7 attracting each other, so that it is possible to improve resistance to disturbances caused by vibrations and the like.

[0058] Furthermore, as the plunger 3 is driven, the permanent magnet 7 moves together with the center post 4 in the internal space S thereof, thereby reducing the influence of the magnetic force between the center post 4 and the permanent magnet 7, particularly while the plunger 3 is moving from the first position to the second position. This makes it easier for the magnetic flux to converge between the plunger body 30 and the center post 4, thereby stabilizing the attraction characteristics of the solenoid device 1.

[0059] Furthermore, when the plunger 3 is positioned in the second position, the magnetic body is formed of the convex portion 61b, which is part of the cover 61 that covers the internal space S of the center post 4, making it easy to form a magnetic body that is attracted to the permanent magnet 7 placed in the internal space S of the center post 4.

[0060] Furthermore, since the magnetic body is constituted by the convex portion 61b that protrudes from the cover 61, the stroke amount of the plunger 3 can be adjusted by the amount of protrusion of the convex portion 61b.

[0061] Furthermore, the permanent magnet 7 is attracted to the center post 4 when the plunger 3 is positioned in the first position, thereby not only enabling the plunger 3 to be self-held at two stop positions, but also enabling the solenoid device 1 to be made smaller since it is composed of a single permanent magnet 7.

[0062] Furthermore, by fitting the return spring 5 provided in the internal space S of the center post 4 to the outside of the protrusion 61b of the cover 61, the protrusion 61b can suppress the deflection of the spring 5 and improve the linearity of the plunger 3. Note that the return spring 5 may be fitted to the inner circumferential surface of a cylindrical protrusion 161b protruding from the cover 161, as in the modified example shown in Fig. 6, as long as it can be inserted and fitted into the protrusion of the cover.

[0063] Furthermore, the permanent magnet 7 arranged on the mounting portion 31b of the rod 31 has a flange portion 32b of the retainer 32 and a retaining ring 33 on both axial sides thereof, and at the two stopping positions of the plunger 3, the flange portion 32b of the retainer 32 and the retaining ring 33 abut against the magnetic body, thereby preventing collision between the permanent magnet 7 and the magnetic body and making the permanent magnet 7 less likely to be damaged.

[0064] Furthermore, in this embodiment, the permanent magnet 7 is annular and is journaled on the cylindrical portion 32a of the retainer 32. Therefore, even if the flange portion 32b or the snap ring 33 of the retainer 32 comes into contact with a magnetic body, the permanent magnet 7 can deform or tilt slightly, thereby mitigating the impact on the permanent magnet 7.

[0065] In addition, in this embodiment, the retainer 32 has a cylindrical portion 32a and a flange portion 32b, and is shaped to fit the inner circumferential surface and the axially right end face of the permanent magnet 7, and the snap ring 33 is fixed in abutment against the axially left end face of the cylindrical portion 32a of the retainer 32, thereby increasing the strength of the retainer 32 and the snap ring 33 that protect the permanent magnet 7.

[0066] Furthermore, in this embodiment, the retainer 32 and the snap ring 33 are formed from a magnetic material such as iron, and therefore a yoke is formed on the inner diameter side of the permanent magnet 7, away from the inner circumferential surface of the center post 4, thereby enabling the magnetic flux of the permanent magnet 7 to be balanced and dense.

[0067] The permanent magnet 7 may be sandwiched in the axial direction between a retainer 132 formed in an annular, thin plate shape and a snap ring 33, as in the modified example shown in FIG.

[0068] Furthermore, the permanent magnet is not limited to being annular, and may be configured, for example, as in the modified example shown in Fig. 8, in which a recess 107a is provided on the end face on the right side in the axial direction of a disk-shaped permanent magnet 107, and an attachment portion 131b of a rod 131 is press-fitted into the recess 107a to be fixed. The permanent magnet 107 is protected by a disk 134 made of a magnetic material such as iron and fixed to the end face on the left side in the axial direction of the permanent magnet 107, and by a retainer 132 that is the same as that in the modified example shown in Fig. 7. The permanent magnet 107 and disk 134 may be fixed by the magnetic flux of the permanent magnet 107, but it is preferable to use a method such as bonding with an adhesive or press-fitting using irregularities (not shown). [Example]

[0069] A self-holding solenoid device according to a second embodiment will be described with reference to Fig. 9. Note that a description of the same configuration as in the first embodiment will be omitted.

[0070] As shown in FIG. 9, in this embodiment, the solenoid device 201 differs from the first embodiment mainly in that the center post 204 is shorter in the axial direction and the protrusion amount of the convex portion 261b of the cover 261 that constitutes the solenoid case 6 is small.

[0071] In this way, by reducing the amount of protrusion of the convex portion 261b of the cover 261 and molding it so that the axial right end face of the convex portion 261b is flush with the axial right end face of the outer diameter portion of the cover 261, the manufacturing cost of the cover 261 can be reduced. [Example]

[0072] A self-holding solenoid device according to a third embodiment will be described with reference to Fig. 10. Note that a description of the same configuration as in the first embodiment will be omitted.

[0073] 10, in this embodiment, the solenoid device 301 differs from the first embodiment in that a cylindrical protrusion 361b is provided to protrude from the cover 361 that constitutes the solenoid case 6, and that the mounting portion 331b of the rod 331 is long in the axial direction and is supported by a bearing 362 provided on the inner peripheral surface of the protrusion 361b of the cover 361. Note that the provision of the bearing 362 eliminates the need for the bearing 42 provided on the inner peripheral surface of the shaft hole 4b of the center post 4 in the first embodiment.

[0074] In this way, by inserting the attachment portion 331b of the rod 331 into the cylindrical protrusion 361b of the cover 261 and supporting it by the bearing 362, the eccentricity of the rod 331 can be reduced.

[0075] In this embodiment, the volume of the internal space S' of the cylindrical protrusion 361b changes when the plunger 3 is moved between the two stop positions. Therefore, it is necessary to allow the fluid (gas or oil) filling the internal space S' of the protrusion 361b to breathe between it and the internal space S of the center post 4. In this regard, the clearance between the center post 4 and the bearing 362 may serve as a flow path, but it is preferable to provide a groove extending in the axial direction on the inner peripheral surface of the bearing 362 or the protrusion 361b. [Example]

[0076] A self-holding solenoid device according to a fourth embodiment will be described with reference to Fig. 11. Note that the description of the same configuration as in the first and second embodiments will be omitted.

[0077] As shown in FIG. 11, in this embodiment, the solenoid device 401 differs from the first embodiment in that the recess 404a of the center post 404 is short in the axial direction and is similar to that of the second embodiment, and the shaft hole 4b is long in the axial direction.

[0078] In this way, by lengthening the axial hole 4b of the center post 404 in the axial direction, the magnetic field lines of the permanent magnet 7 are less likely to affect the nested shape area where the plunger body 30 and the center post 404 face each other, making it easier for the magnetic flux to converge between the plunger body 30 and the center post 404, thereby stabilizing the attraction characteristics of the solenoid device 401.

[0079] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0080] For example, in the above embodiment, a configuration in which a reverse current is applied to a coil as a driving source for releasing the self-holding function of the solenoid device is described, but this is not limited to this, and a configuration in which a coil for moving the movable iron core in a direction toward the fixed iron core and a coil for moving the movable iron core in a direction away from the fixed iron core are separately arranged may also be used.

[0081] In addition, in the above embodiment, the permanent magnet is described as being a single ring-shaped or disk-shaped magnet (see Figure 8), but this is not limited to this. For example, multiple permanent magnets may be evenly arranged around the outer periphery of the shaft portion of the movable iron core.

[0082] Furthermore, the shape of the nested state at the opposing portion of the movable iron core and the fixed iron core may be freely configured as long as it can optimize the magnetic flux density.

[0083] Furthermore, when the plunger 3 is positioned at the first or second position, the retainer and the fixed core or the retaining ring and the protrusion of the cover do not necessarily need to abut each other, and they may be spaced apart as long as they are positioned at other parts. [Explanation of symbols]

[0084] 1 Self-holding solenoid device 2 Solenoid molding 3 Plunger (movable core) 4 Center post (fixed iron core, magnetic material) 4b Shaft hole 5 Spring 6 Solenoid case (fixed core) 7. Permanent magnets 8 Lower plate (fixed core) 20 coils 30 Plunger body 31 Rod (shaft) 31b Mounting part 32 Retainer 32a Cylindrical part 32b flange 33 Retaining ring 40 Cylindrical part 41 Flange 60 Case body 61 Cover (magnetic) 61b Convex part (magnetic material) 70 through holes EM magnetic field lines M magnetic field lines S interior space

Claims

1. A self-holding solenoid device comprising a coil, a movable iron core, a fixed iron core, and a permanent magnet, the self-holding solenoid device moving the movable iron core between two stop positions, The movable core has a shaft portion that protrudes in the axial direction, The fixed core has a shaft hole through which the shaft portion is inserted, A self-holding solenoid device in which the permanent magnet, which is attracted to a magnetic body, is disposed on the shaft portion that is inserted into the internal space of the fixed iron core via the shaft hole.

2. 2. The self-holding solenoid device according to claim 1, wherein the magnetic body is a part of a cover that closes the internal space of the fixed iron core.

3. 3. The self-holding solenoid device according to claim 2, wherein the magnetic body is a protrusion projecting from the cover.

4. 4. The self-holding solenoid device according to claim 1, wherein the permanent magnet is attracted to the fixed iron core when the movable iron core is at a stop position where the movable iron core is spaced apart from the fixed iron core.

5. a spring is provided in the internal space of the fixed iron core to bias the movable iron core in a direction away from the fixed iron core; 4. The self-holding solenoid device according to claim 3, wherein the spring is inserted and fitted into the protrusion.

6. 6. The self-holding solenoid device according to claim 5, wherein the spring is fitted onto the outside of the protrusion.

Images