JPH10172407A - Electromagnetic relay and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic relay in which its reliability is improved and performance of heat radiation from a moving contact spring or a coil is enhanced in an electromagnetic relay in which an armature, standing in an counter position to an opening end of a core and a yoke is fixed at the yoke to be movable in rocker through a moving contact spring. SOLUTION: This electromagnetic relay is provided with its body 2 loaded on a base 1, and a cover 3 covering the body 2 mounted on a base 1. The body 2 is also provided with a coil 22 wound around a coil bobbin 21, and covered at least on its peripheral part with a protection layer 33, and a core 23 penetrating the coil bobbin 21, and a yoke 24 fixed at an edge of the core 23, and a moving contact spring 27 fixed tight at the yoke 24, and an armature 28 standing in a counter position to an opening end of the core 23 and the yoke 24 supported to be movable in rocker through a moving contact spring 27. The circumference of the coil 22 is covered with a thermally conductive resin layer 4, and besides the resin layer 4 and the base 1 or the cover 3 are made come closely into contact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic relay in which an armature facing an open end of an iron core and a yoke is fixed to the yoke via a movable contact spring, and more particularly to heat radiation from a movable contact spring or a coil. The present invention relates to an electromagnetic relay whose reliability is improved by improving performance.

In recent years, a large number of electromagnetic relays have been incorporated in a control circuit as means for controlling a power unit such as a motor and a solenoid. However, in an electromagnetic relay for controlling a power unit along with a reduction in size and weight of a control circuit. Also, realization of high current capacity and miniaturization is desired.

When an electromagnetic relay is energized, the coil itself generates heat corresponding to the current value due to Joule heat caused by the resistance inside the coil, and the resistance of the contacts, the contact resistance between the contacts, and the resistance of the fixed contact spring and the movable contact spring. Joule heat resulting from the heating of the movable contact spring.

[0004] The heat generated in the electromagnetic relay is radiated by heat diffusion and heat radiation by the base and the cover, heat conduction through each terminal, and the like. This may be a cause of defective insulation or deformation of an insulating material such as a coil bobbin.

[0005] Therefore, there is a demand for the development of an electromagnetic relay which enhances the heat radiation performance from a movable contact spring or a coil to improve reliability.

[0006]

2. Description of the Related Art FIG. 6 is a side sectional view showing a main part of a conventional electromagnetic relay. As shown in FIG. 6, the conventional electromagnetic relay has an electromagnetic relay main body 2 mounted on a base 1 and a cover 3 mounted on the base 1. The electromagnetic relay main body 2 includes a coil 22 wound around a coil bobbin 21 and a coil bobbin. It has an iron core 23 passing through the center of 21.

The L-shaped yoke 24 has a long axis 25 side attached to the bobbin 21 in parallel with the iron core 23 and a short axis 26 side caulked to the lower end of the iron core 23, and is formed of an elastic metal plate. One side of the L-shaped movable contact spring 27 is attached and fixed to the long axis 25 side of the yoke 24.

An armature 28 facing the open end face of the iron core 23 and the yoke 24 is fixed to the other side of the movable contact spring 27 and is swingably supported. That is, the movable contact 29 is fixed to the vicinity of the tip of the side on which the armature 28 is swingably supported.

A break-side fixed contact 30 and a make-side fixed contact 31 are provided so as to sandwich a movable contact 29 fixed to the tip of a contact support spring 27. Before energizing the coil 22, the armature 28
However, the movable contact 29 is separated from the iron core 23 and the yoke 24 and is in contact with the break-side fixed contact 30.

When the coil 22 is energized, the armature 28 is attracted to the iron core 23 and the yoke 24 and moves together with the movable contact spring 27 fixed to the armature 28, and before energizing the coil 22, the armature 28 contacts the break-side fixed contact 30. The movable contact 29 that has been in contact moves and contacts the fixed contact 31 on the make side.

[0011]

The above-mentioned electromagnetic relay generally generates heat by a current applied to the coil and a current flowing through a contact in an operating state, and the heat generated in the coil is Joule heat caused by resistance inside the coil. The amount of heat generated increases as the applied current increases.

Further, the heat generated in the contact portion is Joule heat caused by the resistance around the contact and the resistance of the fixed contact spring and the movable contact spring. The heat is increased as the current flowing through the contact increases or the contact closes. The amount of heat generated increases as the period of time increases.

The heat generated in the electromagnetic relay is radiated by heat diffusion and heat radiation by the base and the cover, heat conduction through each terminal, and the like. The amount of heat dissipated through the base, the cover and the terminals is constant.

In such an electromagnetic relay, if the current capacity is increased or the size is reduced without changing the structure, the amount of heat generated becomes larger than the heat dissipation capability, and the internal temperature of the electromagnetic relay rises, resulting in poor insulation of the coil and the coil bobbin. There is a problem that the insulating material is deformed.

An object of the present invention is to provide an electromagnetic relay in which the performance of radiating heat from a movable contact spring or a coil is enhanced to improve reliability.

[0016]

FIG. 1 is a side sectional view showing an electromagnetic relay according to the present invention. The same object is denoted by the same symbol throughout the drawings.

The above problem has an electromagnetic relay main body 2 mounted on the base 1 and a cover 3 mounted on the base 1 and covering the electromagnetic relay main body 2. The electromagnetic relay main body 2 is wound around a coil bobbin 21 and has at least an outer periphery. Part of which is covered with a protective layer 33 and a coil 23 which penetrates the coil bobbin 21
And a yoke 24 fixed to one end of the iron core 23; a movable contact spring 27 fixed to the yoke 24; and open ends of the iron core 23 and the yoke 24 that are swingably supported through the movable contact spring 27. And at least the periphery of the coil 22 is covered with a thermally conductive resin layer 4 and the resin layer 4 is in close contact with the base 1 or the cover 3. Is done.

As described above, the electromagnetic relay according to the present invention in which the coil is covered with the resin layer having excellent heat conductivity and the resin layer is in close contact with the base or the cover, the heat generated in the coil or the movable contact spring is generated by the resin. Since the heat is radiated through the layer, the heat radiation performance is improved.

As a result, it is possible to increase the current applied to the coil to increase the attraction force and increase the capacity of the contact portion.
Even if the size and capacity of the electromagnetic relay are reduced, the rise in internal temperature can be suppressed within a range in which insulation failure of the coil and deformation of the insulating material do not occur.

That is, it is possible to realize an electromagnetic relay in which the heat radiation performance from the movable contact spring or the coil is improved and the reliability is improved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a sectional side view showing a first embodiment of the present invention, FIG. 3 is a diagram showing a temperature rise of a coil in the first embodiment, and FIG. 4 is a side showing a second embodiment of the present invention. FIG. 5 is a sectional view showing the temperature rise of the movable contact spring in the second embodiment.

As shown in FIG. 1, the electromagnetic relay of the present invention has an electromagnetic relay main body 2 mounted on a base 1 and a cover 3 mounted on the base 1, and the electromagnetic relay main body 2 is a coil bobbin.
A coil 22 wound around 21 and an iron core 23 penetrating through the center of the coil bobbin 21 are provided.

The L-shaped yoke 24 is attached to the coil bobbin 21 so that the long axis 25 side is parallel to the iron core 23 and the short axis 26 side is the iron core 23.
One side of an L-shaped movable contact spring 27 formed of an elastic metal plate is attached to and fixed to the long axis 25 side of the yoke 24.

The armature 28 facing the open end face of the iron core 23 and the yoke 24 is fixed to the other side of the movable contact spring 27 and is swingably supported. That is, the movable contact 29 is fixed to the vicinity of the tip of the side on which the armature 28 is swingably supported.

A break-side fixed contact 30 and a make-side fixed contact 31 are arranged so as to sandwich the movable contact 29 fixed to the tip of the movable contact spring 27. Before the coil 22 is energized, the armature 28
However, the movable contact 29 is separated from the iron core 23 and the yoke 24 and is in contact with the break-side fixed contact 30.

When the coil 22 is energized, the armature 28 is attracted by the iron core 23 and the yoke 24 and moves together with the movable contact spring 27 fixed to the armature 28. The movable contact 29 that has been in contact moves and contacts the fixed contact 31 on the make side.

The difference between the conventional electromagnetic relay and the electromagnetic relay of the present invention is that at least one of the base 1 and the cover 3 is made of ceramics, and the thermal conductivity and electric conductivity between the electromagnetic relay main body 2 and the base 1 or the cover 3 are different. This is in that a resin layer 4 having excellent insulation properties is interposed.

That is, at least the periphery of the coil 22 and the area fixed to the yoke 24 of the movable contact spring 27 are covered with the resin layer 4 made of epoxy resin filled with SiO ₂ powder or Al ₂ O ₃ powder. The base 1 or the cover 3 is adhered to the surface of the resin layer 4.

The most general method for forming a resin layer between the electromagnetic relay main body 2 mounted on the base 1 and the cover 3 mounted on the base 1 is to interpose the resin layer between the electromagnetic relay main body 2 and the base 1. This is a potting method in which a fixed amount of liquid resin is injected into a space and cured.

However, in this method, since the resin is injected after the cover 3 is mounted on the base 1, it is necessary to close the injection hole after the injection, and the resin flows along the movable contact spring and the coil bobbin due to the capillary phenomenon. The spring characteristic of the rising movable contact spring is changed.

Moreover, the lead terminals 32 penetrating the base 1
When there is a slight gap between the base plate 1 and a through hole (not shown) provided in the base 1, and the lead terminal 32 penetrates the base 1 obliquely and a resin layer is formed, the lead terminal 32 can be formed on a printed circuit board of an electromagnetic relay. Implementation becomes difficult.

As a method for solving such a problem, the electromagnetic relay main body 2 is mounted on a molding die, the lead terminal 32 is fixed at a predetermined position, and the resin which has been heated and allowed to flow is filled with the cavity of the molding die. There is a molding method in which a resin layer is formed by injecting the resin into a resin layer.

The above problem can be solved by adopting the molding method. However, since the high-temperature resin is injected into the cavity of the molding die at high pressure, the diameter of the wire forming the coil is about 0.1 mm.
mm of the polyurethane copper wire or insulation between the wires may be broken.

Therefore, in the method of manufacturing an electromagnetic relay according to the present invention, the surface of the coil 22 is impregnated with a resin that cures at room temperature to form a protective layer 33, and the electromagnetic relay main body 2 in which the coil is protected is formed by a molding die (not shown). The resin layer 4 is formed on a mold by a molding method.

In the first embodiment formed to confirm the effect of the present invention, as shown in FIG.
In mounting, the coil bobbin 21 is brought into close contact with the base 1 and the cover 3 attached to the base 1 is brought into close contact with the resin layer 4.

In a conventional coil not covered with a resin layer, when a current is applied for 1000 seconds as shown in FIG.
The temperature rises to 80 ° C., but in the case of the coil covered with the resin layer in the first embodiment, the temperature rise becomes 40 ° C. as shown by the broken line in FIG.

In the second embodiment of the present invention, the area of the movable contact spring 27 fixed to the yoke 24 is covered with the resin layer 4 as shown in FIG. The inner wall of the cover 3 attached to the base 1 is in close contact with the resin layer 4.

In a conventional movable contact spring without a resin layer, when a current of 20 A is applied for 1000 seconds as shown in FIG.
The temperature rises to 90 ° C., but in the movable contact spring of the second embodiment covered with the resin layer, the temperature rises by 50
℃, almost halved.

As described above, the periphery of the coil, the area fixed to the yoke of the movable contact spring, or both are covered with a resin layer having excellent heat conductivity, and the resin layer is adhered to the base or the cover. In the electromagnetic relay of the present invention, heat generated in the coil or the movable contact spring is radiated through the resin layer, so that the heat radiation performance is improved.

As a result, it is possible to increase the current applied to the coil to increase the attraction force and to increase the capacity of the contact portion.
Even if the size and capacity of the electromagnetic relay are reduced, the rise in internal temperature can be suppressed within a range in which insulation failure of the coil and deformation of the insulating material do not occur.

That is, it is possible to realize an electromagnetic relay in which the heat radiation performance from the movable contact spring or the coil is enhanced and the reliability is improved.

[0042]

As described above, according to the present invention, it is possible to provide an electromagnetic relay in which the heat radiation performance from the movable contact spring or the coil is improved and the reliability is improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an electromagnetic relay according to the present invention.

FIG. 2 is a side sectional view showing the first embodiment of the present invention.

FIG. 3 is a diagram showing a temperature rise of a coil in the first embodiment.

FIG. 4 is a side sectional view showing a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a temperature rise of a movable contact spring in a second embodiment.

FIG. 6 is a side sectional view showing a main part of a conventional electromagnetic relay.

[Explanation of symbols]

 1 Base 2 Electromagnetic relay body 3 Cover 4 Resin layer 21 Coil bobbin 22 Coil 23 Iron core 24 Yoke 25 Long axis 26 Short axis 27 Movable contact spring 28 Armature 29 Movable contact 30 Break side fixed contact 31 Make side fixed contact 32 Lead terminal 33 Protective layer

Claims (5)

[Claims] An electromagnetic relay main body mounted on a base;
A cover attached to the base and covering the electromagnetic relay main body, wherein the electromagnetic relay main body is wound around a coil bobbin and has at least an outer peripheral portion covered with a protective layer; an iron core penetrating the coil bobbin; A yoke fixed to one end of the iron core, a movable contact spring fixed to the yoke, and an armature that is swingably supported via the movable contact spring and faces the open ends of the iron core and the yoke. An electromagnetic relay having at least a periphery of the coil covered with a thermally conductive resin layer, and the resin layer being in close contact with the base or the cover. 2. The electromagnetic relay according to claim 1, wherein a region of the movable contact spring fixed to the yoke is covered with a thermally conductive resin layer, and the resin layer is in close contact with a base or a cover. 3. The electromagnetic relay according to claim 1, wherein the resin layer is formed of an epoxy resin filled with a SiO ₂ powder or an Al ₂ O ₃ powder. 4. The electromagnetic relay according to claim 1, wherein the base or the cover is formed of a ceramic. 5. The method for manufacturing an electromagnetic relay according to claim 1, further comprising a protective layer forming step and a resin layer forming step performed prior to mounting the electromagnetic relay body on a base. Now, a resin that cures at or near room temperature,
A protective layer is formed on the coil surface by impregnating or applying to the coil.In the resin layer forming step, the electromagnetic relay main body on which the protective layer is formed is mounted on a molding die, and at least a base or a base is provided around the coil. A method for manufacturing an electromagnetic relay, comprising: forming a resin layer that can adhere to a cover.