JP2007142221A - Stator core and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stator core 10 a magnetism interrupt section 11, which has a greater magnetic reluctance characteristic and less dispersions and without deformation distortion, and to provide a simple and manufacturing-cost-effective manufacturing method of the stator core 10. <P>SOLUTION: In the stator core 10 containing therein a plunger 12 movable in the axial direction and formed with a magnetic circuit for acting a magnetic attractive force onto the plunger 12; a constriction 16 is provided to the front of the plunger 12 in the axial direction, the constriction 16 forms a thin structure 15, and a press machine loads tensile stress on the thin structure 15 and gives process hardening to the thin structure 15. Since the thin structure 15 has a greater magnetic reluctance, and further the hardening increases the magnetic saturation, the magnetic attractive force acting on the plunger 12 becomes further stronger. Thus, dispersions in magnetic attractive force can be suppressed and robustness can be improved. Moreover, since the resistance to deformation can be increased by the hardening, production of deformation distortions can be suppressed to attain smooth movement of the plunger 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic solenoid of a solenoid valve, and more particularly to a structure of a stator core that accommodates a plunger therein so as to be movable in an axial direction, and a method for manufacturing the stator core.

[Conventional technology]
Generally, an electromagnetic solenoid of a solenoid valve includes a stator core that accommodates a plunger in an axially movable manner, and the stator core applies a magnetic attractive force to the plunger when energizing an electromagnetic coil disposed on the outer peripheral side of the stator core. In order to form a magnetic circuit for this purpose, the stator core is provided with a magnetic shielding part.

  2. Description of the Related Art Conventionally, in order to stably apply a large magnetic attractive force to a plunger, there is an electromagnetic solenoid having a structure in which a gap or a thin portion is provided in a magnetic blocking portion of a stator core to increase magnetic resistance. Further, there is an electromagnetic solenoid in which a stator core is configured by integrating a magnetic body, a nonmagnetic body, and a magnetic body in this order, and is disclosed in Patent Document 1.

  In the electromagnetic solenoid disclosed in Patent Document 1, a magnetic material, a non-magnetic material, and a magnetic material are arranged in advance in the axial direction and integrated by electrical resistance welding, ultrasonic welding, press-fit projection, friction welding, laser welding, or the like. The inner peripheral side and the outer peripheral side are subjected to cutting as post-processing. Therefore, the degree of cylindricity is high, and the clearance between the stator core and the plunger can be reduced, so that it is easy to increase the magnetic attractive force of the plunger.

[Problems with conventional technology]
However, the structure and the manufacturing method of the electromagnetic solenoid disclosed in Patent Document 1 have many manufacturing processes and require precision machining, which may increase the manufacturing cost.

  On the other hand, in an electromagnetic solenoid (see FIG. 5) constituted by a stator core having a thin-walled structure that is simple to manufacture and low in manufacturing cost, for example, when applied to an electromagnetic solenoid of a sealing valve of a fuel tank for an automobile, The part generally has a thickness of 0.5 mm or more. When the thickness is 0.5 mm, the magnetic attraction force produces a force of 1400 gf, but when the thickness is only 0.1 mm thick, the attraction force is reduced by 100 gf. Magnetic attraction is very sensitive. That is, the magnetic attraction force varies with respect to the variation in the thickness of the thin portion, and the variation is large, which affects the operation of the electromagnetic solenoid. In addition, high processing accuracy is required to reduce this variation, and this also raises a concern about an increase in manufacturing cost.

Further, structurally, if the thickness of the thin portion is reduced, the magnetic resistance can be increased, which is advantageous for increasing the magnetic attractive force. However, when it is assembled with other magnetic circuit components such as a yoke, press-fitting is necessary, and the deformation may remain in the thin wall portion due to the press-fitting and the plunger may not move smoothly. Alternatively, there may be a problem that the plunger is not assembled.
JP 2003-269638 A

  Therefore, the present invention has been made in view of the above problems, and has a structure of a stator core having a large magnetoresistance characteristic of the magnetic interrupting portion of the stator core, little variation, and no deformation strain, and a simple, manufacturing cost. An object of the present invention is to provide a method for manufacturing a stator core that does not cost.

[Means of Claim 1]
According to the present invention, in a stator core of an electromagnetic solenoid that houses a plunger movably in the axial direction and forms a magnetic circuit for applying a magnetic attractive force to the plunger, the stator core is provided with a magnetic blocking portion in the axial direction front. The magnetic shielding part is characterized by providing a thin part in the constituent material of the stator core to increase the magnetic resistance, further increasing the magnetic saturation by working and hardening the thin part, and strengthening the magnetic attractive force acting on the plunger. .

  According to this, although the thin part where the magnetic resistance is increased is magnetically saturated, the magnetic saturation is increased and the magnetic attractive force can be increased by further work hardening. Thereby, variation in magnetic attractive force can be suppressed and robustness can be improved.

[Means of claim 2]
The stator core of the electromagnetic solenoid according to claim 1, wherein the thin portion is processed in a constricted shape from both the outer peripheral surface and the inner peripheral surface of the stator core, and the work hardening is performed by applying a tensile stress of the thin portion. Yes.

  According to this, by thinning (apparatus), the thickness of the thin portion can be reduced by plastic deformation of tension, work hardening can be promoted, magnetic saturation is increased, magnetic attraction force is strengthened, and variation is suppressed. It becomes possible. Further, since the deformation strength of the thin portion is increased, sufficient strength can be maintained even with a thin thickness of the thin portion with respect to press fitting of other components such as a yoke.

[Means of claim 3]
The stator core of the electromagnetic solenoid according to claim 1, wherein the thin portion is processed in a constricted shape from both the outer peripheral surface and the inner peripheral surface of the stator core, and the work hardening is performed by applying a compressive stress of the thin portion. Yes.

  According to this, work hardening can be promoted by a compression process (apparatus) that is simpler than a tensile process (apparatus), and therefore work hardening can be imparted easily and reliably. In addition, this makes it possible to increase the magnetic attraction force and suppress variations thereof. Further, since the deformation strength of the thin portion is increased, it is possible to sufficiently maintain the strength with the thickness of the thin portion with respect to press-fitting of other components such as a yoke.

[Means of claim 4]
The stator core of the electromagnetic solenoid according to claim 1, wherein the thin portion is processed in a constricted shape from an outer peripheral surface or an inner peripheral surface of the stator core, or both, and the constricted shape is a press from the outer peripheral surface or the inner peripheral surface or both. The work hardening is performed by applying a stress simultaneously with the processing of the thin wall portion by the constricted shape.

  According to this, the work hardening by compression deformation and the formation of the thin portion can be configured at the same time by the forging process itself, so that the processing process can be simplified. In addition, the variation in the thickness of the thin portion is reduced by forging, and the deformation strength of the thin portion is increased by forging and hardening, so the thin portion is thinner than the press-fitting of other components such as a yoke. Sufficient strength can be maintained even with a thick wall. In addition, since the magnetic resistance of the thin wall portion is increased and the magnetic saturation is increased by work hardening, it is possible to increase the magnetic attractive force and suppress the variation.

[Means of claim 5]
2. The method of manufacturing a stator core of an electromagnetic solenoid according to claim 1, wherein the thin portion is processed in a constricted shape from the outer peripheral surface or the inner peripheral surface of the stator core, or both to increase the magnetic resistance, and in the axial direction of the thin portion. By applying tensile stress or compressive stress, plastic deformation is caused in the thin-walled portion, work hardening is imparted, the magnetic saturation of the thin-walled portion is increased, and the magnetic attractive force acting on the plunger is strengthened. The solenoid stator core manufacturing method is adopted.

  According to this, work hardening can be promoted and magnetic saturation can be easily increased by simply applying an axial tensile stress or compressive stress. Further, since the thin portion is formed by the constriction processing from the inner and outer peripheral surfaces, the remaining plastic deformation does not protrude from the inner and outer peripheral surfaces of the thin portion. Therefore, the magnetic attraction force of the plunger that moves on the inner peripheral surface of the thin wall portion can be easily increased without requiring post-processing of the inner peripheral surface. Moreover, since it can process with a simple process and apparatus, it becomes possible to reduce manufacturing cost.

  The best mode of the present invention will be described together with Example 1 shown in the drawings.

[Configuration of Example 1]
FIG. 1 shows a conceptual cross section of an electromagnetic solenoid of an electromagnetic valve in this embodiment.

In FIG. 1, the electromagnetic solenoid 1 includes a stator core 10, a coil 13, a yoke 14, and a plunger 12 that constitute a magnetic circuit as main components.
The stator core 10 is a cylindrical body having one end (left side in the figure) having a hollow cylindrical shape with a hook and the other end (right side in the figure) having an open shape. A magnetic shield 11 having a V-shaped constriction 16 is formed uniformly from the inner and outer peripheral surfaces in the vicinity of the cylindrical flange. The magnetic shielding portion 11 is a thin portion 15 structurally formed by the constriction 16 and is a magnetic saturation portion with increased magnetic resistance in terms of magnetic circuit. Further, the thin-walled portion 15 is provided with work hardening by stress concentration of axial stress due to tension or compression, thereby increasing the magnetic saturation and increasing the deformation strength.

  The plunger 12 has a solid cylindrical shape and is accommodated on the inner peripheral side of the stator core 10 so as to be capable of reciprocating in the axial direction. One end of the plunger 12 is located at the magnetic blocking portion 11 of the stator core 10, and the other end of the plunger 12 is a cylindrical body having a length substantially coincident with the open end of the stator core 10, and generates a magnetic attractive force as will be described later. It has a structure to do.

  The coil 13 is a winding in which a coated conducting wire is wound in multiple layers around a bobbin, and is molded into a cylindrical shape with a resin. At the same time, it is integrally formed with a connector (not shown) for supplying power to the coil 13 and is electrically connected. And it becomes a cylindrical shape which has a smooth inner peripheral surface, is coaxially fitted to the outer peripheral surface of the stator core 10, is excited by energization as will be described later, and generates a magnetic flux.

The yoke 14 has a hollow cylindrical shape with one end open and the other end partially bottomed. The coil 13 is accommodated in the hollow portion, the open end thereof is in contact with the flange portion of the stator core 10, and the other end is fitted to the outer peripheral portion of the open end of the stator core 10. Thereby, a path (magnetic circuit) of magnetic flux generated by the coil 13 is formed.
The magnetic circuit of the electromagnetic solenoid 1 is configured by the above combination.

  The coil 13 is energized by energization, and the generated magnetic flux flows through the magnetic circuit. However, magnetic saturation is high in the magnetic blocker 11, and the magnetic circuit bypasses the plunger 12 and the magnetic flux flows. As a result, the plunger 12 generates a magnetic attractive force. The magnetic attractive force acts on the left side of the plunger 12 in the figure, and gives a thrust and a stroke to a valve body (not shown). As is well known, the plunger 12 always receives a biasing force from a spring (not shown) and is pushed back to a stopper position (not shown) when the coil 13 is not energized. This position corresponds to a steady position when no power is supplied.

Next, an example of a method for manufacturing the stator core 10 will be described. FIG. 2 is a cross-sectional view of a main part of a processing step and a processing apparatus in the case where a tensile stress is applied to the stator core 10 to perform work hardening.
The stator core 10 has a V-shaped constriction 16 formed in advance at a predetermined position of the cylindrical portion from the inner and outer peripheral surfaces by cutting to form a thin portion 15 having a predetermined thickness (see FIG. 2A). The thin-walled portion 15 due to the constriction 16 is configured so that stress is easily concentrated, and even if plastic deformation occurs, the shape does not protrude from the inner and outer peripheral surfaces after deformation, and the movement of the plunger 12 and the like is not hindered. .

  Next, the stator core 10 is mounted on a tensioning jig 20 as a processing device, and is tensioned by a press machine (not shown) (see FIG. 2B). As shown in FIG. 2B, the tensile jig 20 is composed of a punch 21 and a die 26. The punch 21 has a double cylindrical shape so as to sandwich the constriction 16 of the stator core 10, and is provided with an outer punch 22 in contact with the outer peripheral side of the stator core 10 and an inner punch 23 in contact with the inner peripheral side. Each of the outer punch 22 and the inner punch 23 is open and the other is a bottomed cylindrical body. And it is divided at least in the axial direction (half-divided), and each has a separate and independent structure. The bottomed portion of each of the outer punch 22 and the inner punch 23 is provided with a concavo-convex shape in the diametrical direction. Are connected to the double outer punch 22 and the inner punch 23, and a pin 24 is driven into the through hole to form a hinge structure. Thereby, the outer punch 22 and the inner punch 23 can open and close the open ends around the pins, respectively.

  On the other hand, the die 26 is a structure that clamps the flange portion of the stator core 10 from the outer periphery and the inner periphery, and is a pedestal that firmly holds the flange portion against the pull of the punch 21.

  When the stator core 10 is mounted on the tensile processing jig 20 and the press machine is operated, the punch 21 is pulled upward in the drawing. When a tensile force is applied to the pin 24 of the punch 21, the protrusions 25 having substantially the same shape as the constriction 16 of the stator core 10 provided on the open end side of the outer punch 22 and the inner punch 23 act so as to bite into the constriction 16 of the stator core 10, respectively. As the punch 21 is raised, the thin wall portion 15 due to the constriction 16 receives a tensile stress. When the punch 21 further rises, the tensile stress exceeds the yield stress of the constituent material of the stator core 10, and plastic deformation occurs. The plastic deformation can proceed effectively in a concentrated manner, that is, in a concentrated manner by applying a tensile force to the thin portion 15. When the predetermined residual strain is reached, the rise of the punch 21 is stopped, that is, the press machine is stopped, and the stator core 10 is taken out (see FIG. 2C). In the stator core 10, the thin portion 15 due to the constriction 16 is further uniformly thinned, and work hardening accompanying residual strain occurs, and magnetic saturation is increased by work hardening.

  The processing device of the tensile processing jig 20 having the above-described configuration is a highly reliable device that reliably generates work hardening only in the thin portion 15 due to the constriction 16. Since the stress concentration is intended to be achieved, the tensioning jig 20 may have a slightly simplified configuration. For example, the punch 21 is composed of an outer punch 22 and an inner punch 23 which are double cylindrical bodies, and the open end side of the stator core 10 is sandwiched between the outer punch 22 and the inner punch 23 without being divided in half. Or a structure for generating a tensile force, or a structure in which a through hole is formed at a right angle in the axial direction on the open end side of the stator core 10 and a tensile force is generated through a tension pin. . According to this, although a through hole and a clamping allowance are left in the stator core 10, it does not impair the magnetic circuit characteristics at all, and does not impair the strength characteristics in terms of mechanical strength. There is a feature that the processing jig 20 can be used.

[Operation of Example 1]
The operation of the electromagnetic solenoid 1 of the electromagnetic valve according to this embodiment will be described below.
A stator core 10 of an electromagnetic solenoid 1 that accommodates a plunger 12 therein so as to be movable in the axial direction and forms a magnetic circuit for applying a magnetic attractive force to the plunger 12, wherein the stator core 10 has a constriction 16 forward in the axial direction. The thin portion 15 is formed by the constriction 16 to increase the magnetic resistance, and the magnetic saturation is increased by work hardening by tensile plastic deformation in the axial direction. Therefore, when the coil 13 is energized by energization, the generated magnetic flux flows through the magnetic circuit described above. However, in the magnetic circuit of the stator core 10, the magnetic interrupter 11 has high magnetic saturation, so that the magnetic flux is bypassed to the plunger 12. Will flow. Thereby, a magnetic attractive force acts on the plunger 12. At this time, since the magnetic saturation is further increased by imparting work hardening, a large amount of magnetic flux bypasses the plunger 12, and the magnetic attractive force acts more strongly.

[Effect of Example 1]
In the present embodiment, a magnetic blocking portion 11 is provided in front of the stator core 10 in the axial direction, and the magnetic blocking portion 11 forms a thin portion 15 due to a constriction 16 from the inner and outer peripheral surfaces, and this thin portion 15 is loaded with a tensile stress. Since work hardening is given by this, the magnetic saturation of the thin part 15 is raised more, As a result, while increasing magnetic attraction force, the dispersion | variation can be suppressed and robustness can be improved. In addition, since the work hardening is applied, the deformation strength of the thin wall portion 15 is also increased, so that the occurrence of deformation strain at the time of assembly can be suppressed. No deformation strain (protruding deformation) remains, and the plunger 12 can always move smoothly in the stator core 10.

  Further, since the work hardening can be obtained simply by a plastic working by a tensile stress of the thin portion 15 by a press machine, it can be completed with a simple processing apparatus and processing steps, and the manufacturing cost can be reduced.

[Modification 1]
FIG. 3 shows a first modification of the stator core 10.
This stator core 10 differs in the following points. Example 1 is manufactured by applying work stress by applying tensile stress. However, the present embodiment is not limited to this, and is manufactured by applying work stress by applying compressive stress. The stator core 10 can be manufactured by mounting the tension processing jig 20 of the processing apparatus shown in FIG. 2 described above and using the press machine for compression processing. Since it is a jig | tool structure, the compression processing jig | tool 30 shown in FIG.3 (b) which can implement simple and reliable compression processing may be sufficient.

  A method for manufacturing the stator core 10 using the compression processing jig 30 will be described. First, in the stator core 10 of the workpiece, as in the first embodiment, a V-shaped constriction 16 is formed in advance at a predetermined position of the cylindrical portion from the inner and outer peripheral surfaces by cutting, and a thin portion 15 having a predetermined thickness is formed. (See FIG. 3A). The thin-walled portion 15 due to the constriction 16 is configured so that stress is easily concentrated, and even if plastic deformation occurs, the structural shape does not protrude from the inner and outer peripheral surfaces after deformation, and movement of the plunger 12 and the like is not hindered. Yes.

  Next, the stator core 10 is mounted on a compression jig 30 that is a processing device, and is compressed by a press machine (see FIG. 3B). As shown in FIG. 3 (b), the compression processing jig 30 includes a punch 31 and a die 36, and the punch 31 has a disk-like plate shape with a recess so as to be fitted to the open end of the stator core 10. In addition, the work can be hardened by the action of only the axial compressive stress by the compressive force generated by the lowering of the punch 31. That is, even if the stator core 10 starts to be inclined and deformed, the tilt does not progress and the guide of the concave portion is surely deformed in the axial direction.

  On the other hand, the die 36 has a structure in which the flange portion of the stator core 10 is clamped from the outer periphery and the inner periphery as in the first embodiment, and the flange portion of the stator core 10 is clamped from the outer periphery, and the cylindrical body of the stator core 10 is connected to the inner periphery. It is a pedestal with a concentric core that can prevent bending deformation and the like.

  When the stator core 10 is mounted on the compression processing jig 30 and the press machine is operated, the punch 31 descends downward in the figure. The stator core 10 is compressed by the compressive force of the punch 31, and stress concentrates on the thin portion 15 due to the constriction 16, so that a large compressive stress is received. As the punch 31 further descends, the compressive stress exceeds the yield stress of the constituent material of the stator core 10 and plastic deformation occurs. When the predetermined residual strain is reached, the lowering of the punch 31 is stopped, that is, the press machine is stopped, and the stator core 10 is taken out (see FIG. 3C). Although the stator core 10 has a thin portion 15 that is uniformly and slightly thicker than the initial state, magnetic saturation is increased by work hardening associated with this residual strain.

[Modification 2]
In Example 1 of the present invention, a constriction 16 by cutting is provided in advance, and tensile stress is applied and work-hardened to actively concentrate the thin-walled portion 15 by the constriction 16, but not limited thereto, The manufacturing method of processing the constriction 16 and imparting the work hardening of the thin portion 15 at the same time by forging may be used. An example is shown in FIG.
FIG. 4 is a cross-sectional view of the main part of the processing step and the processing apparatus when work hardening is imparted to the thin portion 15 due to the constriction 16 in the stator core 10.

  As shown in FIG. 4A, the stator core 10 is a straight cylindrical body having no constriction, and has a predetermined initial shape.

  Next, the stator core 10 is mounted on a forging jig 40, which is a processing apparatus, and pressed by a press machine (see FIG. 4B). As shown in FIG. 4B, the forging jig 40 includes a punch 41 and a die 46. The die 46 includes an outer die 47, an inner die 48, and a pedestal 49, and each of the outer die 47 and the inner die 48 is a split die that is divided into a large number of at least three or more. This split die forms an annular integrated die by arranging and assembling many pieces on the circumference.

  The outer die 47 is provided with a constricted protrusion 44 for processing a predetermined constriction on the inner side, and a tapered surface is formed on the outer side. Similarly, the inner die 48 is provided with a constricted protrusion 45 for processing a predetermined constriction on the outer side, and a tapered surface is formed on the inner die 48. In addition, the pedestal 49 is a fixed pedestal having smoothness and flatness that holds the flange portion of the stator core 10 and supports vertical load and horizontal load acting on the outer die 47 and the inner die 48.

  The punch 41 has a double cylindrical shape composed of an outer punch 42 and an inner punch 43. The outer periphery of the outer punch 42 has a tapered surface with the same gradient as the tapered outer peripheral surface of the outer die 47. After the taper is fitted, the axial load of the outer punch 42 is changed to the centripetal load (horizontal load) of the outer die 47. Can be converted to Similarly, the inner punch 43 has a tapered surface whose outer periphery has the same gradient as the tapered inner peripheral surface of the inner die 48. After the taper fitting, the axial load of the inner punch 43 is changed to the radial load (horizontal) of the inner die 48. Load).

  When the stator core 10 is mounted on the forging jig 40 and the press machine is operated, the punch 41 descends downward in the figure. The axial compressive force of the punch 41 is equally transmitted to the outer punch 42 and the inner punch 43, the inner peripheral taper surface of the outer punch 42 is taper-fitted with the outer peripheral taper surface of the outer die 47, and similarly, the outer peripheral taper surface of the inner punch 43 is The inner die 48 is taper-fitted to the inner peripheral tapered surface. When the punch 41 is further lowered, that is, when a compressive force is further applied, a taper fitting causes a horizontal compressive force in the centripetal direction to the outer die 47 and a horizontal compressive force in the radial direction to the inner die 48 of the cylindrical body of the stator core 10. It acts on the outer circumference and the inner circumference, respectively. However, since the outer die 47 and the projections 44 and 45 of the inner die 48 are pressed in a concentrated manner, that is, stress is concentrated, plastic deformation easily proceeds, and a constriction is formed as the compressive force increases.

  When the projecting portions 44 and 45 are all pressed to form the constriction 16, the projecting portion structures of the outer die 47 and the inner die 48 are the inner peripheral surface of the flat outer die 47 provided with the projecting portions 44 and 45 and the outer periphery of the inner die 48, respectively. Since the structure is supported by the surface, the constriction processing does not progress any further. Therefore, the predetermined constriction shape and the thickness of the thin portion 15 due to the constriction 16 are formed uniformly. When the predetermined constricted shape is formed, the lowering of the punch 41 is stopped, that is, the press machine is stopped, and the stator core 10 is taken out (see FIG. 4C). The stator core 10 can form the magnetic shielding part 11 in which the thin part 15 due to the constriction 16 has a predetermined thickness, the magnetic resistance is increased, the work hardening accompanying plastic deformation is given, and the magnetic saturation is increased. it can.

  In Modification 2, the constriction 16 is formed on the inner and outer peripheral surfaces of the stator core 10 at the same time. However, the present invention is not limited to this, and the inner peripheral surface and the outer peripheral surface may be divided and processed in order. Good. According to this, the forging jig becomes easier, and the manufacturing cost can be reduced.

  Moreover, in the modified example 2, the constriction 16 is processed on both the inner and outer peripheral surfaces, and the thin wall portion 15 and its work hardening are provided. 15 and its processing hardening may be used. Necking using the forging jig 40 is performed by a press machine and can be easily adopted with high die accuracy and high processing accuracy, and it is easy to achieve the limit thickness of the thin portion 15 with a small variation. In addition, by adopting a metal core structure for the punch 41 and the die 46, it is relatively easy to prevent the occurrence of deformation deformation. Therefore, the stator core 10 having the thin portion 15 that does not hinder the movement of the plunger 12 can be easily provided without incurring manufacturing costs.

(Example 1) which is a conceptual principal part sectional drawing of an electromagnetic solenoid. It is a process diagram in the case of applying a tensile stress to the stator core and hardening it, (a) is a cross-sectional view of the stator core at the time of constriction processing, and (b) is a processing device required for applying a tensile stress to the stator core and hardening it. (C) is sectional drawing at the time of completion extraction of a stator core (Example 1). It is a process diagram in the case of applying a tensile stress to the stator core and hardening it, (a) is a cross-sectional view of the stator core at the time of constriction processing, and (b) is a processing device required for applying a tensile stress to the stator core and hardening it. It is a fragmentary sectional view, (c) is a sectional view when the stator core is completed and taken out (Modification 1). It is a process diagram in the case of applying a tensile stress to the stator core and hardening it, (a) is a cross-sectional view of the stator core at the time of constriction processing, and (b) is a processing device required for applying a tensile stress to the stator core and hardening it. It is a fragmentary sectional view, (c) is a sectional view when the stator core is completed and taken out (Modification 2). It is a conceptual principal part sectional drawing of the stator core of an electromagnetic solenoid (conventional example).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electromagnetic solenoid 10 Stator core 11 Magnetic interruption | blocking part 12 Plunger 13 Coil 14 Yoke 15 Thin part 16 Constriction (constriction shape)
20 Tension processing jig 21, 31, 41 Punch 22, 42 Outer punch 23, 43 Inner punch 24 Pins 25, 44, 45 Protrusions 26, 36, 46 Die 30 Compression processing jig 40 Forging jig 47 Outer die 48 Inner die 49 Pedestal

Claims (5)

In a stator core of an electromagnetic solenoid that houses a plunger movably in the axial direction and forms a magnetic circuit for applying a magnetic attractive force to the plunger,
The stator core is provided with a magnetic shielding part in the axial direction front,
The magnetic interrupting portion is provided with a thin portion in the constituent material of the stator core to increase the magnetic resistance, and further, the thin portion is processed and hardened to increase magnetic saturation and to increase the magnetic attractive force acting on the plunger. A featured electromagnetic solenoid stator core. The stator core of the electromagnetic solenoid according to claim 1,
The electromagnetic solenoid stator core according to claim 1, wherein the thin portion is processed in a constricted shape from both an outer peripheral surface and an inner peripheral surface of the stator core, and the work hardening is performed by applying a tensile stress of the thin portion. The stator core of the electromagnetic solenoid according to claim 1,
The electromagnetic solenoid stator core according to claim 1, wherein the thin portion is processed in a constricted shape from both an outer peripheral surface and an inner peripheral surface of the stator core, and the work hardening is performed by applying a compressive stress of the thin portion. The stator core of the electromagnetic solenoid according to claim 1,
The thin portion is processed in a constricted shape from the outer peripheral surface or inner peripheral surface of the stator core, or both, and the constricted shape is a forging process by pressing from the outer peripheral surface or the inner peripheral surface, or both,
The stator core of an electromagnetic solenoid, wherein the work hardening is performed by applying stress simultaneously with the processing of the thin wall portion by the constricted shape. In the manufacturing method of the stator core of the electromagnetic solenoid according to claim 1,
By processing the thin-walled portion in a constricted shape from the outer peripheral surface or inner peripheral surface of the stator core, or both, increasing the magnetic resistance, and applying tensile stress or compressive stress in the axial direction of the thin-walled portion, A method for manufacturing a stator core of an electromagnetic solenoid, wherein plastic deformation is applied to a thin-walled portion, work hardening is imparted, the magnetic saturation of the thin-walled portion is increased, and the magnetic attractive force acting on the plunger is strengthened.

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