JPH0729729A - Solenoid - Google Patents

Abstract

PURPOSE:To provide a solenoid which can improve the counter surfaces of a plunger and a core in abrasion resistance without deteriorating the solenoid in plunger holding power. CONSTITUTION:Only the outer peripheries of counter surfaces 4a and 6a, which bear against each other, of a core 4 and a plunger 6 of a solenoid are subjected to a nitriding treatment. The nitriding treatment is executed through a plasma treatment process which uses the normal glow region of a glow discharge. Nitrides 4c and 6c are formed only on the peripheries of the counter surfaces 4a and 6a of the core 4 and the plunger 6 by the use of a normal glow region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic solenoid, and more particularly to a surface hardening treatment of a plunger or core of an electromagnetic solenoid.

[0002]

2. Description of the Related Art Conventionally, as an electromagnetic solenoid applied to an electromagnetic valve or the like, in Japanese Utility Model Laid-Open No. Sho 56-117518, a core and the entire surface of a plunger of which surface is nitrided is proposed. This nitriding treatment is performed for the purpose of reducing the friction coefficient of the plunger, preventing rust generation, and preventing surface wear. In particular, the opposing surfaces of the core and the plunger repeat strong collisions due to the driving of the plunger,
A nitriding process is performed on the entire facing surface to prevent wear.

[0003]

However, if the entire opposing surfaces of the core and the plunger are subjected to a nitriding treatment for improving the wear resistance, the presence of the nitrided layer weakens the ferromagnetic properties. In this case, the magnetic resistance of the nitride layer portion increases, and the magnetic flux passing through the magnetic path formed by the core and the plunger cannot be efficiently transmitted. As a result, there is a problem that the force for holding the plunger is weakened by the magnetic flux.

As a result of examining the wear state of the facing surface of the core due to the collision of the plunger, as shown in FIG.
It was found that the outer surface of the facing surface of 0 was greatly worn and the inner surface was not easily worn. For convenience of explanation, FIG.
Shows only wear of the core 10. This is because the plunger 11 is supported inside the electromagnetic solenoid by the sliding cylinder 12 with a certain clearance, so that the plunger 11 collides in a tilted state as shown by the chain double-dashed line due to friction between the two. . That is, the outer peripheral portion of the facing surface of the plunger 11 collides intensively with the outer peripheral portion of the facing surface of the core 10. Therefore, in order to prevent the opposite surfaces of the plunger and the core from being worn, it is sufficient to perform the nitriding treatment on the outer peripheral portions of the opposite surfaces.

The present invention has been made to solve the above problems, and its purpose is to improve the wear resistance of the opposing surfaces of the plunger and the core without impairing the holding force of the plunger. To provide a solenoid.

[0006]

In order to solve the above problems, the present invention has a core and a plunger arranged on the same axis, and an exciting coil arranged outside the core and the energizing control of the exciting coil. Therefore, in the electromagnetic solenoid that attracts the plunger to the core, the surface hardening treatment is applied only to the outer peripheral portion of at least one of the facing surfaces of the core and the plunger where the core and the plunger contact each other. The summary will be given.

Further, in the electromagnetic solenoid in which the core and the plunger are arranged on the same axis line, the exciting coil is arranged outside thereof, and the plunger is attracted to the core by controlling the energization of the exciting coil, The outline is that surface hardening treatment is applied to at least one of the facing surfaces of the core and the plunger in which the core and the plunger are in contact with each other, and the hardening treatment film thickness is increased toward the outer peripheral portion of the facing surface. To do.

Further, in the electromagnetic solenoid in which the core and the plunger are arranged on the same axis and the exciting coil is arranged outside the same, and the plunger is attracted to the core by controlling energization of the exciting coil, The gist of the invention is that an annular groove is formed on at least one of the facing surfaces of the core and the plunger where the core and the plunger are in contact with each other, and the outer peripheral portion of the groove is surface-hardened.

The surface hardening treatment is preferably a nitriding surface treatment.

[0010]

Therefore, in the invention described in claim 1, since the outer surface of the facing surface of the core or the plunger is surface-hardened, the facing surface of the core is inclined with respect to the facing surface of the core. Even if a collision occurs, abrasion of the collision site is suppressed. In addition, since the surface of the facing surface of the core and the plunger except the outer peripheral portion is not surface-hardened,
The magnetic flux holding the plunger passes through the inner peripheral portion of the facing surface without resistance.

According to the second aspect of the present invention, since the outer surface of the facing surface of the core or the plunger is surface-hardened, the facing surface of the core is inclined with respect to the facing surface of the core. Even if a collision occurs, abrasion of the collision site is suppressed. Further, since the inner peripheral side of the facing surface of the core and the plunger is thinner than the outer peripheral portion, the magnetic flux holding the plunger passes relatively well through the inner peripheral portion of the facing surface.

According to the third aspect of the invention, the same effect as that of the first aspect of the invention can be achieved, and the surface hardened layer can be formed on the outer peripheral portion of the groove. or,
In the invention according to claim 4, the surface-hardened layer can be formed at low cost.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention will now be described with reference to FIGS.
It will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of an essential part of an electromagnetic solenoid, in which an exciting coil 2 is wound around an outer circumference of a bobbin 1, and a cylindrical core 4 is fitted inside the bobbin 1 via a yoke 3. There is. A sliding cylinder 5 is connected to the outside of the tip of the core 4, and a plunger 6 is vertically movable in the sliding cylinder 5 extending below the sliding cylinder 5. The core 4
The plunger 6 is formed of a ferromagnetic material such as iron. A coil spring 7 is arranged between the core 4 and the plunger 6. The upper end of the coil spring 7 is the core 4
Concave portion 4b formed in the central portion of the lower surface 4a as the facing surface of the
Is attached to. The lower end of the coil spring 7 has a hole 6b formed in the center of the upper surface 6a as the facing surface of the plunger 6.
Is attached to. The coil spring 7 holds the lower surface 4a of the core 4 and the upper surface 6a of the plunger 6 at a predetermined distance. When the exciting coil 2 is energized, a closed magnetic circuit is formed by the yoke 3, the core 4 and the plunger 6, and the plunger 6 is attracted to the core 4 against the elastic force of the coil spring 7.

Nitriding portions 4c and 6c are formed on the lower surface 4a of the core 4 and the upper surface 6a of the plunger 6.
The nitriding portions 4c and 6c are formed only on the outer peripheral portions of the surfaces 4a and 6a, as shown in FIGS. The range of the nitriding portions 4c and 6c is a range including a portion where the plunger 6 immediately collides with each other when the plunger 6 is sucked by the core 4.

Next, each surface 4 of the core 4 and the plunger 6
A method of nitriding only the outer peripheral portions of a and 6a will be described. In this embodiment, the facing surfaces 4a, 6a of the core 4 and the plunger 6 are subjected to plasma treatment using the normal glow region of glow discharge shown in FIG. In the plasma processing in the normal glow region, the sputtering action is concentrated on the corners of the object to be processed. In the present embodiment, this characteristic is utilized, and when the facing surface 4a, 6a of the core 4 or the plunger 6 is subjected to the plasma treatment in the normal glow region, the sputtering action causes the facing surface 4a, 6a.
Concentrated on the outer periphery of 6a. And the facing surface 4
Annular nitriding portions 4c and 6c are formed on the outer peripheral portions of a and 6a. In this embodiment, the nitriding portion has a thickness of 10 to 20 μm.
It is formed so as to be about m. In this method,
The nitriding treatment is also performed on the side surfaces of the facing surfaces 4a and 6a that follow the outer peripheral portion, but this can be used for rust prevention of the core 4 and the plunger 6 and for reducing the friction coefficient of the plunger 6.

Further, in order to form the nitriding layers 4c and 6c only on the outer peripheral portions of the facing surfaces 4a and 6a, the abnormal glow region may be used for the plasma treatment. That is,
As shown in FIG. 5, masking 8 is applied in advance to the surfaces and side surfaces of the facing surfaces 4a and 6a excluding the outer peripheral portions. In that state, plasma treatment is performed in the abnormal glow region.
Then, by removing the masking 8, the facing surface 4
The nitriding portions 4c and 6c are formed only on the outer peripheral portions of a and 6a. A coating material is used as the masking material, or a baffle plate such as an iron plate is placed.

Next, the operation of the electromagnetic solenoid configured as described above will be described. When the exciting coil 2 of the electromagnetic solenoid is not energized, the plunger 6 is located below due to the elastic force of the coil spring 7. On the other hand, when the excitation coil 2 is energized, the magnetic flux passes through the plunger 6 via the yoke 3 and the core 4. Then, the plunger 6 is attracted to the core 4 against the elastic force of the coil spring 7,
The lower surface 4a of the and the upper surface 6a of the plunger 6 collide. At this time, since the plunger 6 collides with the core 4 in a tilted state, the outer peripheral edge of the plunger 6 directly collides with the outer peripheral portion of the core 4. Since the collision portions are the nitriding portions 4c and 6c, abrasion due to the collision is unlikely to occur.

In the suction state, the nitriding processing section 4
Since c and 6c are formed only on the outer peripheral portions of the respective surfaces 4a and 6a, the magnetic resistance of the both surfaces 4a and 6a does not increase and the magnetic flux passing through the core 4 and the plunger 6 does not decrease.
Therefore, it is possible to prevent the holding force of the plunger 6 from being reduced when energized.

FIG. 6 shows an electromagnetic solenoid A which is not nitrided.
The life test results of the electromagnetic solenoid B and the electromagnetic solenoid C of this embodiment in which the entire lower surface 4a of the core 4 and the upper surface 6a of the plunger 6 are nitrided are shown. That is, the electromagnetic solenoid C of this embodiment is the electromagnetic solenoid B whose entire surface is nitrided.
It was confirmed that the life was almost the same as that of, and the life was much longer than that of the untreated electromagnetic solenoid A.

FIG. 7 shows the test results of the holding forces of the electromagnetic solenoids A, B and C. Electromagnetic solenoid C of this embodiment
The minimum holding voltage and the minimum holding current at the minimum holding force were almost the same as those of the untreated electromagnetic solenoid A. And
The minimum holding voltage and the minimum holding current at the minimum holding force of the electromagnetic solenoid B were the largest. Therefore, it was confirmed that the electromagnetic solenoid C of this example has the same large holding force as the untreated electromagnetic solenoid A.

As described above, in this embodiment, only the outer peripheral portions of the surfaces 4a, 6a of the core 4 and the plunger 6 are nitrided. Therefore, the entire surface of the electromagnetic solenoid B is nitrided.
The same wear resistance as was obtained. Further, it has a holding force equivalent to that of the unprocessed electromagnetic solenoid A.

The present invention is not limited to the above embodiments, but may be configured as follows, for example, without departing from the spirit of the invention. (1) In the above embodiment, the nitriding treatment is performed only on the outer peripheral portions of the facing surfaces 4a and 6a of the core 4 or the plunger 6. By subjecting this to plasma processing using the normal glow region as well, as shown in FIG.
The nitriding portion 6c may be formed such that the nitriding layer becomes thicker toward the outer peripheral portion of the upper surface 6a. In this case, the plasma treatment process for forming the nitriding portion is simpler than that in the case of forming only the outer peripheral portion.

(2) As shown in FIG. 9, for example, the core 4
The annular groove 4d is formed on the facing surface 4a of the above, and the nitriding treatment by the normal glow discharge is performed. When the groove 4d is formed in this manner, the sputtering is performed on the facing surface 4a.
Since it is concentrated on the outer peripheral portion, the nitriding portion 4c can be easily formed only on the outer peripheral portion. When such a groove 4d is provided, the nitriding portion 4a is intensively formed on the outer peripheral portion of the facing surface 4a without masking 8 even in the abnormal glow discharge region portion of the use area of the present invention shown in FIG. can do.

(3) In this embodiment, the nitriding treatment is performed as the surface hardening treatment, but other than this, the surface hardening treatment may be performed using chromium or boron. Also in this case, core 4
Also, with respect to the life of the plunger 6, the same effect as in the case of the nitriding treatment is obtained.

(4) In the above embodiment, the lower surface 4 of the core 4 is
a and the nitriding portions 4c and 6c on the upper surface 6a of the plunger 6.
However, it may be formed on only one of them. However, in this case, the core 4 and the plunger 6
It is needless to say that the number of lifespans of No. 2 is inferior to the case where both are treated, but is better than the case where both are not treated.

(5) The nitriding treatment may be performed by a salt bath nitriding method (tuftride). In this case, as shown in FIG. 5, masking 8 is applied to the surfaces other than the outer peripheral portions of the facing surfaces 4a and 6a. When the masking 8 is removed after the nitriding treatment, the nitriding portion 4 is formed only on the outer peripheral portions of the facing surfaces 4a and 6a.
c, 6c are formed.

[0027]

As described in detail above, according to the invention described in claim 1, it is possible to improve the wear resistance of the opposing surfaces of the plunger and the core without impairing the holding force of the plunger. Play.

According to the second aspect of the invention, in addition to the above effects, the surface hardening treatment can be easily applied to the outer peripheral portions of the facing surfaces of the plunger and the core. According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, the surface hardening treatment can be easily performed only on the outer peripheral portion of the facing surface of the plunger and the core by the plasma treatment in the normal glow region. Can be given. Furthermore, the surface hardening treatment can be performed only on the outer peripheral portions of the facing surfaces of the plunger and the core without masking even by the plasma treatment of the abnormal glow region.

Further, according to the invention described in claim 4, the surface hardening treatment can be performed at a low cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an electromagnetic solenoid as an embodiment embodying the present invention.

FIG. 2 is a vertical cross-sectional view of a main part showing a core and a plunger.

FIG. 3A is a bottom view showing a nitriding portion of a core, and FIG. 3B is a plan view showing a nitriding portion of a plunger.

FIG. 4 is a graph showing current-voltage characteristics of glow discharge.

FIG. 5 is a longitudinal cross-sectional view of essential parts showing a state in which the facing surface and the side surface are masked and the outer peripheral portion of the facing surface is subjected to nitriding treatment.

FIG. 6 is a graph comparing the lives of electromagnetic solenoids depending on the difference in the nitriding treatment of the facing surfaces.

FIG. 7 is a graph comparing the minimum voltage and the minimum current required to obtain the holding force of the plunger of the electromagnetic solenoid due to the difference in the nitriding treatment on the facing surface.

FIG. 8 is a vertical sectional view showing a nitrided state of a plunger facing surface of another example.

FIG. 9 is likewise a vertical cross-sectional view showing a nitrided state of the core facing surface of another example.

FIG. 10 is a vertical cross-sectional view showing a worn state of opposing surfaces of a core and a plunger of a conventional example.

[Explanation of symbols]

2 ... Exciting coil, 4 ... Core, 4a ... Lower surface, 6 ... Plunger, 6a ... Upper surface.

Claims (4)

[Claims] 1. A core (4) and a plunger (6) are arranged on the same axis, an exciting coil (2) is arranged outside the core (4), and the plunger is controlled by energizing the exciting coil (2). In the electromagnetic solenoid adapted to attract (6) to the core (4), the core (4) and the plunger (6) are in contact with each other, and the opposing surfaces (4a, 6a) of the core (4) and the plunger (6) are An electromagnetic solenoid in which at least one of the facing surfaces (4a, 6a) is subjected to a surface hardening treatment only on the outer peripheral portion thereof. 2. A core (4) and a plunger (6) are arranged on the same axis, an exciting coil (2) is arranged outside the core (4), and the plunger is controlled by energizing the exciting coil (2). In the electromagnetic solenoid adapted to attract (6) to the core (4), the core (4) and the plunger (6) are in contact with each other, and the opposing surfaces (4a, 6a) of the core (4) and the plunger (6) are An electromagnetic solenoid characterized in that at least one of the facing surfaces (4a, 6a) is subjected to a surface hardening treatment so that the hardening treatment film thickness becomes thicker toward the outer peripheral portion of the facing surface (4a, 6a). 3. A plunger (6) is provided by arranging a core (4) and a plunger (6) on the same axis and an exciting coil (2) outside the core, and controlling the excitation of the exciting coil (2). In the electromagnetic solenoid adapted to attract (6) to the core (4), the core (4) and the plunger (6) are in contact with each other, and the opposing surfaces (4a, 6a) of the core (4) and the plunger (6) are An annular groove (4d) is formed on at least one of the facing surfaces (4a, 6a), and the groove (4d) is formed.
An electromagnetic solenoid having a surface-hardened outer peripheral portion. 4. An electromagnetic solenoid, wherein the surface hardening treatment according to any one of claims 1 to 3 is a nitriding surface treatment.