Electromagnetic relay and method of manufacturing electromagnetic relay

A press-fit fixing portion fixes a drive unit and a relay unit by press-fitting a claw portion and the recess portion. A sealing member is provided on an outside of the relay unit and the drive unit. An inner cover forms a sealed space for sealing an arc-extinguishing gas together with the sealing member. An electromagnetic relay is configured to make it possible both an adjustment of a press-fitting amount of the claw portion and the recess portion and an adjustment of the gap between a ceramic insulator at an end of a shaft and a movable element by making each of the relay unit and the drive unit in a manufacturing process to the same state as in when a magnetizing coil is energized.

TECHNICAL FIELD

The disclosure of this specification relates to a closed type electromagnetic relay and a method of manufacturing the same.

BACKGROUND

An electromagnetic relay fills an arc-extinguishing gas in a sealed space. Therefore, the electromagnetic relay requires both a process of adjusting a gap for turning on and off a circuit and a process of forming the sealed space. In the above aspects, or in other aspects not mentioned, there is a need for further improvements in an electromagnetic relay and a method of manufacturing the same.

SUMMARY

An electromagnetic relay disclosed in this specification has the following configurations. A drive unit includes a magnetizing coil which forms a magnetic field by energization, a fixed core which is placed on a side of an inner diameter of the magnetizing coil, a yoke which accommodates the magnetizing coil and the fixed core, a movable core which is movable relative to the fixed core, a shaft which is able to reciprocate in an axial direction and is fixed to the movable core and a return spring which urges the movable core in a direction away from the fixed core. A relay unit includes a frame made of an insulating material, a fixed terminal fixed to the frame, a movable element which is provided on a side opposite to the movable core with respect to the fixed terminal and is movable relative to the fixed terminal, and a contact pressure spring which urges the movable element to a side to the fixed terminal. A press-fit fixing portion which fixes the drive unit and the relay unit by press-fitting a claw portion provided on one of the yoke or the frame and a recess portion provided on the other one. A sealing member in a plate-shape is provided outside the relay unit and the drive unit. The external connection terminal is fixed to the sealing member while being inserted through a hole of the sealing member, and is joined to the fixed terminal. The inner cover is joined to the sealing member in a state in which the drive unit and the relay unit are accommodated therein, and forms a sealed space for sealing the arc-extinguishing gas inside together with the sealing member.

The electromagnetic relay is configured to be able to adjust a gap between the end of the shaft and the movable element and be able to adjust a press-fitting amount between the claw portion and the recess portion, by bringing them into a state where the movable contact of the movable element and the fixed contact of the fixed terminal come into contact with each other, and the movable component and the fixed core come into contact with each other, in a state before attaching the sealing member and the inner cover. The movable component means any of a shaft, a movable core, and a component that moves integrally with them.

According to this, in the manufacturing process, the electromagnetic relay enables to adjust the gap formed between the end of the shaft and the movable element when the magnetizing coil is energized, at a state before assembling the sealing member and the inner cover to an intermediate product in which the drive unit and the relay unit are combined. Then, after adjusting the gap, the external connection terminal fixed to the sealing member and the fixed terminal are joined, the sealing member and the inner cover are joined, and the arc extinguishing gas is injected into the closed space formed by the sealing member and the inner cover. Therefore, since a potential process which may act stress on the drive unit or the relay unit after adjusting the gap between the end of the shaft and the movable element is only a joining process for the external connection terminal and the fixed terminal, it is possible to suppress changing of the gap. Therefore, the electromagnetic relay1is possible to reduce differences of the gap Gs for each product in a configuration in which the drive unit10and the relay unit20are accommodated in the closed space in which the arc extinguishing gas is sealed.

In the case that an insulating member such as a ceramic insulator is fixed to an end of the shaft on a side to the movable element, the end of the shaft means the end of the insulating member.

The method of manufacturing an electromagnetic relay disclosed in this specification includes the following steps. First, it prepares a drive unit in which a magnetizing coil which forms a magnetic field by energization, a fixed core which is placed on a side of an inner diameter of the magnetizing coil, a yoke which accommodates the magnetizing coil and the fixed core, a movable core which is movable relative to the fixed core, a shaft which is able to reciprocate in an axial direction and is fixed to the movable core and a return spring which urges the movable core in a direction away from the fixed core are assembled. It prepares a relay unit in which a frame made of an insulating material, a fixed terminal fixed to the frame, a movable element which is provided on a side opposite to the movable core with respect to the fixed terminal and is movable relative to the fixed terminal, and a contact pressure spring which urges the movable element to a side to the fixed terminal are assembled. It fixes the drive unit and the relay unit by adjusting a press-fitting amount of the claw portion provided on one of the yoke or the frame and the recess portion provided on the other side so that a gap between the end of the shaft and the movable element is adjusted to have a predetermined size in a state where the movable contact included in the movable element and the fixed contact included in the fixed terminal are brought into contact with each other and the movable component and the fixed core are brought into contact with each other. It fixes the sealing member and the external connection terminal in a state where the external connection terminal is inserted through a hole of the sealing member in a plate shape. It joins the external connection terminal and the fixed terminal while arranging the sealing member to which the external connection terminal is fixed on an outside of the relay unit and the drive unit. It forms a sealed space inside an inner cover and the sealing member by joining the inner cover in which the drive unit and the relay unit are accommodated therein and the sealing member. It seals an arc-extinguishing gas in the sealed space formed inside the inner cover and the sealing member.

According to this, the gap between the end of the shaft and the movable element is adjusted when the drive unit and the relay unit are fixed by press-fitting the claw portion provided on one of the yoke or the frame and the recess portion provided on the other side. The electromagnetic relay, which accommodates the drive unit and the relay unit in the closed space, is formed by joining the external connection terminal fixed to the sealing member and the fixed terminal, and joining the sealing member and the inner cover, after the above process. Therefore, since a process which may apply stress on the drive unit or the relay unit after adjusting the gap is only a joining process for the external connection terminal and the fixed terminal, it is possible to suppress changing of the gap. Therefore, this method of manufacturing an electromagnetic relay is possible to reduce differences of the gap Gs for each product in a configuration in which the drive unit and the relay unit are accommodated in the closed space in which the arc extinguishing gas is sealed.

A reference numeral in parentheses attached to each component or the like indicates an example of correspondence between the component or the like and specific component or the like described in embodiments below.

DETAILED DESCRIPTION

It is known that a closed type electromagnetic relay in which a relay unit including a movable element and fixed terminals and a drive unit which drives the movable element of the relay unit are accommodated in a closed space sealed with an arc extinguishing gas such as hydrogen.

The closed type electromagnetic relay described in JPH09-259728A has a configuration in which a gap is formed between a movable element of the relay unit and an end of a shaft when the magnetizing coil of the drive unit is energized. The gap works to make the end of the shaft come into contact with the movable element after increasing a kinetic energy of the shaft in response to turning off of an energization of the magnetizing coil of the drive unit. As a result, a speed separating the movable contact of the movable element from the fixed contact of the fixed terminal, i.e., hereinafter referred to as “separating speed” increases, and a current cutoff performance is improved. The electromagnetic relay described in Patent Literature 1 has a configuration in which a size of the gap is adjusted by a screw mechanism provided on the movable core and the shaft of the drive unit. In addition, this electromagnetic relay has a configuration in which a sealed space for sealing the arc extinguishing gas is formed by joining a sealing container which accommodates the fixed terminals and the movable element, a bottomed cylindrical portion which accommodates the fixed core and the movable core, and a plurality of joining members arranged between the sealing container and the bottomed cylindrical portion.

However, in the manufacturing process, the electromagnetic relay described in JPH09-259728A requires a process for joining the plurality of members for forming the closed space by, e.g., welding process after adjusting the gap between the end of the shaft and the movable element by the screw mechanism. Therefore, in the case that heat of the welding process is conducted to the drive unit or the relay unit, the gap may vary for each product.

It is an object of this disclosure in this specification, in view of the above points, to provide an electromagnetic relay and a method for manufacturing the electromagnetic relay which is capable of reducing differences of gaps formed between an end of a shaft and a movable element when a magnetizing coil is energized in a configuration in which a drive unit and a relay unit are accommodated in a sealed space in which an arc extinguishing gas is sealed.

Embodiments of the present disclosure are described herein with reference to the drawings.

First Embodiment

A first embodiment is described below. As shown inFIGS.1to4, the electromagnetic relay1includes a drive unit10, a relay unit20, a press-fit fixing unit30, a sealing member40, external connection terminals50, an inner cover60, an outer cover70, and the like.

The drive unit10included in the electromagnetic relay1includes a magnetizing coil11, a fixed core12, a yoke13, a movable core14, a shaft15, a return spring16, and the like.

The magnetizing coil11is wound around a bobbin17and is formed in a substantially circular cylindrical shape. The magnetizing coil11forms a magnetic field when it is energized. The fixed core12and the like are arranged in a side to an inner diameter of the magnetizing coil11, i.e., a central hole171formed inside the bobbin17.

The fixed core12is a circular cylindrical member made of a magnetic material, and is formed in a size corresponding to the central hole171of the bobbin17. The fixed core12has a through hole121along a central axis. A part of the shaft15is arranged in the through hole121in a sliding manner.

The yoke13is a member made of a magnetic material, and accommodates the magnetizing coil11and the fixed core12. The yoke13is arranged so as to cover a side of an outer periphery and an axial end portion of the magnetizing coil11. The yoke13has a first yoke member131and a second yoke member132.

The first yoke member131is a member called a stationary, which has a shape in which a plate material made of a magnetic material is bent into a substantially U shape, and covers a side of the outer periphery of the magnetizing coil11and a side of the one end in the axial direction of the magnetizing coil11. An opening133is formed in a portion of the first yoke member131that covers a side of the one end in the axial direction of the magnetizing coil11. The fixed core12and the first yoke member131are joined by fitting a part of the fixed core12into an inside of the opening133.

The second yoke member132is a member called a top plate, which is formed of a plate material made of a magnetic material, is connected to the first yoke member131, and covers a side of the other end in the axial direction of the magnetizing coil11. The second yoke member132is formed with a yoke hole134at a position corresponding to the fixed core12and the movable core14. A shape of an inner circumference of the second yoke member132is a shape corresponding to the movable core14.

The movable core14is a disk-shaped member made of a magnetic material, and is arranged so as to be relatively movable with respect to the fixed core12at a position corresponding to the yoke hole134of the second yoke member132. A shape of an outer circumference of the movable core14corresponds to a shape of the inner circumference of the second yoke member132. The movable core14is formed with a through hole141to which the shaft15is fixed in a penetrating state.

The shaft15is fixed to the movable core14in a state where it is inserted into the through hole141of the movable core14. Further, a portion of the shaft15on a side to the fixed core12is inserted into the through hole121formed in the fixed core12in a sliding manner. Therefore, the shaft15can reciprocate in the axial direction integrally with the movable core14.

Further, the shaft15is formed with a flange portion151having an enlarged outer diameter thereof. A surface of the movable core14on a side to the fixed core12comes in contact with the flange portion151. Therefore, a misalignment between the shaft15and the movable core14is prevented.

Further, a ceramic insulator18is fixed to the end of the shaft15opposite to the fixed core12. When the magnetizing coil11is not energized, the ceramic insulator18and the movable element23come into contact with each other.

Further, a spring holding portion142into which the return spring16is fitted is provided at a portion of the movable core14on a side to the magnetizing coil11. The spring holding portion142is formed by a protrusion protruding from one surface of the movable core14on a side to the return spring16in an annular shape, and the return spring16is fitted on an outer peripheral surface thereof.

One end of the return spring16is held by a spring holding portion142provided on the movable core14, and the other end is in contact with a step portion172provided on the bobbin17. The return spring16urges the movable core14away from the fixed core12.

The fixed core12, the yoke13, the movable core14, and the like included in the drive unit10described above form a magnetic circuit in which the magnetic flux induced by the magnetizing coil11flows when the magnetizing coil11is energized.

As shown inFIG.1, when the magnetizing coil11is not energized during a current is not supplied to the magnetizing coil11, the movable core14is located away from the fixed core12due to an urging force of the return spring16. On the other hand, as shown inFIG.2, when the magnetizing coil11is energized, the movable core14is magnetically attracted to a side to the fixed core12against the urging force of the return spring16, and a movable portion component comes into contact with the fixed core12. The movable component means any of the shaft15, the movable core14, and a component that moves integrally with them. In the present embodiment, the flange portion151of the shaft15constituting the movable component is configured to be in contact with the fixed core12, but the present invention is not limited to this. For example, the movable core14constituting the movable component may be configured to come in contact with the fixed core12.

Next, as shown inFIGS.1to4, the relay unit20included in the electromagnetic relay1includes a frame21, a fixed terminal22, a movable element23, a contact pressure spring24, and the like.

The frame21is made of, for example, an insulating material such as a resin material. The frame21is composed of a base frame25and an intermediate frame26. The base frame25and the intermediate frame26are integrally fixed. The base frame25is provided over the relay unit20and the drive unit10. The intermediate frame26is provided so as to cover a part of the fixed terminal22, the movable element23, and the contact pressure spring24.

A first fixed terminal221and a second fixed terminal222made of a conductive metal are fixed to the base frame25. The first fixed terminal221and the second fixed terminal222are connected to an external electric circuit, not illustrated, which is subject to be a turning on and off control by the electromagnetic relay1. The first fixed contact271is attached to the first fixed terminal221and the second fixed contact272is attached to the second fixed terminal222. The first fixed terminal221and the second fixed terminal222have a shape extending in a direction perpendicular to the paper surface ofFIG.1.

The movable element23is a plate-shaped member made of conductive metal, and is provided on a side opposite to the movable core14with respect to the fixed terminal22. The movable element23is provided in a movable manner in an axial direction of the shaft15with respect to the fixed terminal22. A surface of the movable element23on a side to the fixed core12can come into contact with the ceramic insulator18fixed to the end of the shaft15.

A first movable contact281and a second movable contact282are fixed to the movable element23. When the magnetizing coil11is energized, the first movable contact281is able to come into contact with the first fixed contact271, and the second movable contact282is able to come into contact with the second fixed contact272.

An annular groove261into which one end of the contact pressure spring24is fitted is formed in a central portion of the intermediate frame26. One end of the contact pressure spring24is fitted into the annular groove261and the other end comes in contact with the movable element23. The contact pressure spring24urges the movable element23to a side to the shaft15and to a side to the fixed terminal22. Therefore, the movable core14is magnetically attracted to a side to the fixed core12when the magnetizing coil11is energized, the movable element23moves to a side to the fixed terminal22due to the elastic force of the contact pressure spring24. Then, the first movable contact281and the first fixed contact271come into contact with each other, and the second movable contact282and the second fixed contact272come into contact with each other. An elastic force of the contact pressure spring24is set to be smaller than an elastic force of the return spring16.

As shown inFIG.3, the configuration of the present embodiment is a configuration in which a gap, hereinafter this may be simply referred to as a gap Gs, is formed between the ceramic insulator18provided at the end of the shaft15and the surface of the movable element23on a side to the shaft11, when the magnetizing coil11is energized. The gap Gs formed when the magnetizing coil11is energized improves a current cutoff performance by increasing a separating speed of the movable contacts281and282of the movable element23to separate from the fixed contacts271and272of the fixed terminal22in response to a turning off of a current supply to the magnetizing coil11of the drive unit10. The separating speed is determined by an elastic energies of the contact pressure spring24and the return spring16that come into contact with the movable contacts281and282and the movable element23, and the elastic energies depend on a size of the gap Gs and a magnitude of spring constants. The elastic energy and the kinetic energy have the relationship of the following equation 1.
½·k·x2=½·m·v2(Equation 1)

In Equation 1 above, the left term represents the elastic energy and the right term represents the kinetic energy. “k” is the spring constant. “x” is a distance of the gap Gs. “v” is the separating speed.

Therefore, as described below, the present embodiment provides a configuration in which it is possible to reduce differences of the gap Gs for each product.

As shown inFIG.4, the press-fit fixing portion30is configured of a plurality of claw portions31provided on the yoke13, and a plurality of recess portions32provided on the base frame25and the intermediate frame26, respectively.

The recess portion32provided in the base frame25is called a first recess portion321. The recess portion32provided on a side of the intermediate frame26to the base frame25is called a second recess portion322. The recess portion32provided on the intermediate frame26at a position away from the base frame25with respect to the second recess portion322is referred to as a third recess portion323. On the other hand, among the plurality of claw portions31provided on the yoke13, those provided at positions corresponding to the first recess portion321, the second recess portion322and the third recess portion323are called a first claw portion311, a second craw portion312, and a third claw portion313, respectively. The first claw portion311, the second claw portion312, and the third claw portion313are fixed to the first recess portion321, the second recess portion322, and the third recess portion323by press fitting, respectively. As a result, the relay unit20and the drive unit10described above are fixed.

In a state before the sealing member40and the inner cover60are attached, it is possible to adjust the gap Gs between the end portion of the shaft15, i.e., the ceramic insulator18and the movable element23when the claw portion31and the recess portion32are press-fitted. The gap Gs is adjusted in the same state as when the magnetizing coil11is energized. Specifically, when the claw portion31and the recess portion32are press-fitted, the relay unit20and the drive unit10are brought into the same state as when the magnetizing coil11is energized. The same state as when the magnetizing coil11is energized is a state in which the movable element23and the fixed terminal22included in the relay unit20come in contact with each other, and the movable component and the fixed core12included in the drive unit10come in contact with each other. Then, by adjusting the press-fitting amount between the claw portion31and the recess portion32in order to adjust the gap Gs into a predetermined size, it is possible to set the gap Gs into the predetermined size. For the adjustment of the gap Gs, for example, a jig or gauge, not shown, may be used, or an image taken by a camera may be used.

The sealing member40, the external connection terminals50, the inner cover60, and the outer cover70, described later, are assembled after the above-mentioned adjustment for the gap Gs are performed.

The sealing member40is formed in a substantially rectangular plate shape by a material having insulating properties and impermeable to arc extinguishing gas, such as ceramic. The sealing member40is provided on an outside of the relay unit20and the drive unit10. The sealing member40is provided with a plurality of holes43through which external connection terminals50, coil external connection terminals51, and the gas filling pipe52are inserted. The external connection terminals50, the coil external connection terminals51, and the gas filling pipe52are each fixed to the sealing member40by brazing or the like in a state inserted through the holes43of the sealing member40. The external connection terminal50is joined to the fixed terminal22, and the coil external connection terminal51is joined to the terminal111of the magnetizing coil11.

Here, as shown inFIG.5, joining surfaces22aand50aof the fixed terminals22and the external connection terminals50are formed parallel to the axis Ax of the shaft15. The joining surfaces22aand50aspread parallel to the axis Ax. The fixed terminal22has a convex portion protruding toward the external connection terminal50. The convex portion defines and forms the joining surface22a. The external connection terminal50has a convex portion protruding toward the fixed terminal22. The convex portion defines and forms the joining surface50a. Thereby, when the external connection terminal50and the fixed terminal22are joined, it is possible to reduce a stress acting on the fixed terminal22in the axial direction of the shaft15. Therefore, when the external connection terminal50and the fixed terminal22are joined, the fixed terminal22is prevented from being displaced in the axial direction of the shaft15. Therefore, it is possible to suppress the gap Gs from changing after the gap Gs is set.

As shown inFIGS.1to5, the inner cover60is formed in a box shape by a material such as metal that does not allow the arc-extinguishing gas to permeate. The drive unit10and the relay unit20are accommodated inside the inner cover60. The inner cover60has an opening on a side where the sealing member40is arranged. The sealing member40is arranged on a side to the opening of the inner cover60. Further, a flange61extending outward is provided in an opening of the inner cover60.

A frame member41is provided between the sealing member40and the inner cover60. The frame member41is formed of a material that does not allow the arc-extinguishing gas to permeate, such as metal. The frame member41is annularly formed so as to have substantially the same size as the opening of the inner cover60. In the present embodiment, the frame member41has an L-shaped cross section. Ac entire circumference of one outer edge of the frame member41, i.e., one distal end of the L-shape, and the sealing member40are joined by brazing. Further, an entire circumference of the other outer edge of the frame member41, i.e., the other surface of the L-shape, and the flange61of the inner cover60are joined by resistance welding. Therefore, the sealing member40and the inner cover60are joined via the frame member41in an airtight manner. Then, the sealing member40, the frame member41, and the inner cover60form a sealed space in which the arc-extinguishing gas is sealed. The relay unit20and the drive unit10are accommodated in the closed space.

The outer cover70is formed in a box shape from an insulating material such as resin, and is provided so as to cover an outside of the inner cover60. The outer cover70has an opening on a side where the sealing member40is arranged. The sealing member40is provided to close the opening of the outer cover70. An outer edge portion42of the sealing member40and the inner wall of the opening of the outer cover70are fixed by fitting. Thus, an outer shell of the electromagnetic relay1is configured by the outer cover70and the sealing member40.

The electromagnetic relay according to the present embodiment is configured by the structure described above. Subsequently, the operation of the electromagnetic relay1according to the present embodiment is described.

First, as shown inFIG.1, when the magnetizing coil11is not energized during a current is not supplied to the magnetizing coil11, the movable core14is located away from the fixed core12due to an elastic force of the return spring16. The ceramic insulator18, which is fixed to the end of the shaft15fixed to the movable core14, and the movable element23are in contact with each other, and the movable element23is moving away from the fixed terminal22. Therefore, the first movable contact281and the second movable contact282are held in a state where they are separated from the first fixed contact271and the second fixed contact272. Therefore, the first fixed terminal221and the second fixed terminal222are electrically separated, and the electromagnetic relay1is turned in an off state.

Next, as shown inFIG.2, when the electromagnetic relay1is turned on, the magnetizing coil11is energized. As a result, the magnetic flux induced by energizing the magnetizing coil11flows through the magnetic circuit composed of the movable core14, the fixed core12, the yoke13, and the like, and the movable core14is magnetically attracted to a side to the fixed core12while resisting the elastic force of the return spring16. Then, as the movable core14moves, the shaft15and the ceramic insulator18fixed to the end thereof also move to a side to the fixed core12. Therefore, due to the elastic force of the contact pressure spring24, the movable element23moves to a side to the fixed terminal22, the first movable contact281and the first fixed contact271come into contact with each other, and the second movable contact282and the second fixed contact272come into contact with each other. Therefore, since the first fixed terminal221and the second fixed terminal222are electrically conducted through the movable element23, the electromagnetic relay1is turned in an on state. As a result, an external electric circuit, not shown, to be turned on/off by the electromagnetic relay1is electrically turned in a conductive state. In this state, a gap Gs having a predetermined size is formed between the ceramic insulator18at the end of the shaft15and the movable element23.

Subsequently, when the electromagnetic relay1is switched from the on state to the off state, the energization of the magnetizing coil11is cut off. As a result, the magnetic flux generated by energizing the magnetizing coil11disappears, and the movable core14moves away from the fixed core12, i.e., to a side to the movable core14due to the elastic force of the return spring16. At that time, the movable core14, the shaft15, and the ceramic insulator18collide with the movable element23by increasing a kinetic energy while moving the distance of the gap Gs. In this way, when an electrical connection between the first fixed terminal221and the second fixed terminal222are turned off, the electromagnetic relay1is turned in the off state.

Next, the manufacturing method of the electromagnetic relay1of the present embodiment described above is described with reference to the flowchart ofFIG.6and the explanatory views ofFIGS.7to23.

First, a step S1ofFIG.6is a step of preparing the drive unit10in which the above-mentioned components such as the magnetizing coil11, the fixed core12, the yoke13, the movable core14, the shaft15, and the return spring16are assembled.

Next, a step S2is a step of preparing the relay unit20in which the components such as the frame21, the fixed terminal22, the movable element23, and the contact pressure spring24are assembled.

Subsequently, a step S3is a step of fixing the relay unit20and the drive unit10, and setting the gap Gs between the ceramic insulator18at the end of the shaft15and the movable element23. Specifically, as shown inFIG.7, the method of fixing the relay unit20and the drive unit10press-fits and fixes the first claw portion311, the second claw portion312, and the third claw portion313provided on the yoke13of the drive unit10into the first recess portion321, the second recess portion322, and the third recess portion323provided in the frame21of the relay unit20, respectively. At that time, as shown inFIG.8, both the relay unit20and the drive unit10are brought into the same state as when it is energized. Specifically, the relay unit20is brought into a state where the contacts of the movable element23and the fixed terminal22are in contact with each other. Further, the drive unit10is brought into a state where the movable component and the fixed core12are in contact with each other. The arrow symbol PD indicates the insertion direction in the press-fitting process. In this state, as shown inFIG.9, a press-fitting amount between the claw portion31and the recess portion32is adjusted so that the gap Gs has a predetermined size. As a result, the relay unit20and the drive unit10are fixed in a state where the gap Gs is set to the predetermined size. That is, it is possible to absorb error differences in the dimensions and assembly works of components configuring the relay unit20and the drive unit10by directly adjusting the gap Gs to the target value by adjusting the press-fitting amount between the claw portion31and the recess portion32.

Next, a step S4ofFIG.6is a step of fixing the external connection terminal50and the like to the sealing member40. Specifically, as shown inFIGS.10and11, the external connection terminals50, the coil external connection terminals51, and the gas filling pipe52are inserted through the plurality of holes43of the sealing member40, respectively, and fixed with no gap by brazing. Further, the entire circumference of one outer edge (one tip of the L-shape) of the frame member41is joined to the sealing member40by brazing or the like so as not to have a gap. As a result, as shown inFIG.11, the external connection terminals50, the coil external connection terminals51, the gas filling pipe52, and the frame member41are fixed to the sealing member40.

Subsequently, a step S5ofFIG.6is a step of joining the external connection terminal50and the fixed terminal22. Specifically, as shown inFIGS.12and13, the sealing member40is arranged outside the relay unit20and the drive unit10, and the external connection terminal50and the fixed terminal22are joined. Further, the coil external connection terminal51and the terminal111of the magnetizing coil11are joined.

Here, an example of a plurality of joining methods are described with respect to the joining method between the external connection terminal50and the fixed terminal22.

FIGS.14and15show a first example of the joining method of the external connection terminal50and the fixed terminal22. InFIG.14, the axial direction of the shaft15is indicated by an arrow symbol Ax.

In this first example, the joining surface50aprovided at the end of the external connection terminal50and the joining surface22aprovided at the end of the fixed terminal22are brought into contact with each other, and the joint surfaces are joined by ultrasonic welding while being pressed against each other. The arrow symbol PD indicates the pressurizing direction in the pressurizing step. The arrow symbol VD indicates the vibration direction in the ultrasonic wave applying step. At that time, both the joining surface50aof the external connection terminal50and the joining surface22aof the fixed terminal22are formed parallel to the axis Ax of the shaft15. Therefore, when the external connection terminal50and the fixed terminal22are joined, the stress acting on the fixed terminal22in the axial direction of the shaft15is reduced, and the displacement of the fixed terminal22in the axial direction of the shaft15is suppressed. Therefore, it is possible to suppress change of the gap Gs.

FIGS.16and17show a second example of the joining method of the external connection terminal50and the fixed terminal22.

In this second example, a hole50bis provided at the end of the external connection terminal50, and a dowel22bis provided at the end of the fixed terminal22. Then, after heating the end of the external connection terminal50to widen the hole50b, the dowel22bof the fixed terminal22is inserted into the hole50b. The arrow HT inFIG.16indicates a heating step for widening the hole50b. Then, the end portion of the external connection terminal50is cooled, and the external connection terminal50and the fixed terminal22are joined by the compressive stress thereof. Therefore, the joining method of the second example is a method in which a thermal stress or a mechanical stress acting on the fixed terminal22is smaller than a thermal stress or a mechanical stress acting on the external connection terminal50. Therefore, when the external connection terminal50and the fixed terminal22are joined, the stress acting on the fixed terminal22in the axial direction of the shaft15is reduced, and the displacement of the fixed terminal22in the axial direction of the shaft15is suppressed. The arrow symbol TD inFIG.17indicates the compression direction in which the dowel22bis tightened. Therefore, it is possible to suppress change of the gap Gs.

FIGS.18and19show a third example of the joining method of the external connection terminal50and the fixed terminal22. InFIG.18, the axial direction of the shaft15is indicated by an arrow symbol Ax.

In this third example, a groove50cis provided at the end of the external connection terminal50, and a protrusion22bis provided at the end of the fixed terminal22. Then, after inserting the protrusion22cof the fixed terminal22into the groove50cof the external connection terminal50, the external connection terminal50and the fixed terminal22are joined by applying caulking process from both sides of the external connection terminal50. In the joining method of the third example, both the groove50cof the external connection terminal50and the protrusion22cof the fixed terminal22are formed parallel to the axis Ax of the shaft15. The groove50cdefines and forms the joining surface50a. The protrusion22cdefines and forms the joining surface22a. Therefore, when the external connection terminal50and the fixed terminal22are joined, the stress acting on the fixed terminal22in the axial direction of the shaft15is reduced, and the displacement of the fixed terminal22in the axial direction of the shaft15is suppressed. The arrow symbol DD inFIG.19indicates the direction of plastic deformation that tightens the protrusion22c. Therefore, it is possible to suppress change of the gap Gs.

Subsequently, a step S6ofFIG.6is a step of joining the sealing member40and the inner cover60. In the present embodiment, since the sealing member40is provided with the frame member41, the frame member41and the inner cover60are joined to each other. Specifically, as shown inFIGS.20,21, and22, the L-shaped surface of the frame member41and the flange61of the inner cover60are joined by, for example, seam welding. InFIG.22, an example of a roller electrode used for seam welding is shown by alternate long and short dash lines R1and R2. As a result, the L-shaped surface of the frame member41and the flange61of the inner cover60are welded and joined over the entire circumference, and the sealed space is formed between the inner cover60and the sealing member40.

Next, a step S7ofFIG.6is a step of sealing the arc extinguishing gas in the closed space. For example, hydrogen is used as the arc extinguishing gas. However, the arc extinguishing gas is not limited to this, and may be any gas for extinguishing the arc. The arc extinguishing gas is filled in the closed space through the gas filling pipe52provided in the sealing member40. After filling the closed space with the arc extinguishing gas, the gas filling pipe52is crushed or the like to close the closed space. This prevents the arc extinguishing gas from leaking from the closed space.

Subsequently, a step S8ofFIG.6is a step of fixing the sealing member40and the outer cover70. Specifically, as shown inFIG.23, the inner wall of the opening of the outer cover70and the outer edge portion42of the sealing member40are fixed by fitting. As a result, the electromagnetic relay1is completed.

Here, in order to compare with the electromagnetic relay1of the present embodiment described above, the electromagnetic relay100of a comparative example is described with reference toFIGS.24and25.

In the electromagnetic relay100of the comparative example, the movable core14of the drive unit10is arranged on a side opposite to the relay unit20with respect to the fixed core12. The return spring16is provided between the movable core14and the fixed core12. The movable core14, the fixed core12, and the return spring16are accommodated inside the bottomed cylindrical portion101provided in the central hole of the magnetizing coil11. A screw mechanism102is provided on the inner wall of the central hole of the movable core14and the outer wall of the shaft15. The shaft15and movable core14are fixed by a screw mechanism102.

A plate-shaped first joining member103is provided on a side of the magnetizing coil11to the relay unit20. A second joining member104in a cylindrical shape is provided on a surface of the first joining member103opposite to the magnetizing coil11. A sealing container105in a bottomed cylindrical shape is provided at a portion of the second joint member104opposite to the first joint member103. The bottomed cylindrical portion101, the first joining member103, the second joining member104, and the sealing container105are airtightly joined, and a closed space in which the arc-extinguishing gas is sealed is formed therein.

Both the first fixed terminal221and the second fixed terminal222are placed through the inside and the outside of the sealing container105and fixed to the sealing container105. A movable element23is arranged on a side to the magnetizing coil11with respect to the first fixed terminal221and the second fixed terminal222. The movable element23has an insertion hole231in a central portion. The shaft15is inserted in the insertion hole231of the movable element23. Further, a spring support portion153is provided on the shaft15between the movable element23and the fixed core12. One end of the contact pressure spring24is in contact with the movable element23, the other end is in contact with the spring support portion153, and urges the movable element23toward a side to a tip end of the shaft15. An elastic force of the contact pressure spring24is set to be smaller than an elastic force of the return spring16.

As shown inFIG.24, when the magnetizing coil11is not energized during a current is not supplied to, the movable core14is located away from the fixed core12due to an urging force of the return spring16. Therefore, the movable element23is abutted and supported by the tip end portion of the shaft15, and is moved to a position away from the fixed terminal22. Therefore, the first fixed terminal221and the second fixed terminal222are electrically separated, and the electromagnetic relay100is in the off state. In this state, the distance between the fixed core12and the movable core14is assumed “A”, and the distance between the movable contacts281and282and the fixed contacts271and272is assumed “B”.

On the other hand, as shown inFIG.25, when the magnetizing coil11is energized during a current is supplied to, the movable core14is magnetically attracted to a side to the fixed core12against the urging force of the return spring16, and comes into contact with the fixed core12. Therefore, the shaft15moves to a side to the fixed terminal22, and the contacts of the movable element23and the fixed terminal22come into contact with each other. Therefore, since the first fixed terminal221and the second fixed terminal222are electrically conducted through the movable element23, the electromagnetic relay100of the comparative example is turned in the on state. In this state, a gap Gs is formed between a tip end of the shaft15and the movable element23. This gap Gs is expressed by the following equation 2.
Gs=A−B(Equation 2)

The electromagnetic relay100of the comparative example described above has a configuration in which the size of the gap Gs is adjusted by the screw mechanism102provided on the inner wall of the central hole of the movable core14and the outer wall of the shaft15. Therefore, it provides a configuration in which the size of the gap Gs cannot be directly adjusted.

Further, the electromagnetic relay100of the comparative example provides a configuration in which a sealed space for sealing the arc extinguishing gas is formed by joining the bottomed cylindrical portion101, the first joining member103, the second joining member104, and the sealing container105. Therefore, in the case that a plurality of members for forming the closed space are joined by, for example, a welding process after adjusting the gap Gs, in the manufacturing process of the electromagnetic relay1, heat of the welding process may be conducted to the drive unit10or the relay unit20, there may be a possibility of generating differences of the gap Gs for each product.

The electromagnetic relay1of the present embodiment has the following effects with respect to the electromagnetic relay100of the comparative example described above.

(1) The electromagnetic relay1of the present embodiment is configured to make it possible both an adjustment of the press-fitting amount of the claw portion31and the recess32portion and an adjustment of the gap Gs between the ceramic insulator18at the end of the shaft15and the movable element23by making each of the relay unit20and the drive unit10in the manufacturing process to the same state as in when the magnetizing coil11is energized.

According to this, in the manufacturing process, the electromagnetic relay1enables to adjust the gap Gs while adjusting the press-fitting amount between the claw portions31and the recess portions32, at a state before assembling the sealing member40and the inner cover60to an intermediate product in which the drive unit10and the relay unit20are combined. Then, after adjusting the gap Gs, the external connection terminal50fixed to the sealing member40and the fixed terminal22are joined, the sealing member40and the inner cover60are joined, and the arc extinguishing gas is injected into the closed space formed by the sealing member40and the inner cover60. Therefore, since a potential process which may act stress on the drive unit10or the relay unit20after adjusting the gap Gs between the ceramic insulator18at the end of the shaft15and the movable element23is only a joining process for the external connection terminal50and the fixed terminal22, it is possible to suppress changing of the gap Gs. Therefore, the electromagnetic relay1is possible to reduce differences of the gap Gs in a configuration in which the drive unit10and the relay unit20are accommodated in the closed space in which the arc extinguishing gas is sealed.

As described above, the electromagnetic relay1of the present embodiment can suppress a deformation by processing after adjusting the gap Gs, since it is not necessary to increase size of the return spring16and the magnetizing coil11considering differences of the gap Gs in order to satisfy the performance requirement index, it is possible to reduce size to the electromagnetic relay1. A manufacturing cost may be reduced by suppressing a material cost by reducing the size of the electromagnetic relay1. Further, a fuel efficiency of the vehicle in which the electromagnetic relay1is mounted may be improved by reducing a weight of the electromagnetic relay1.

(2) The electromagnetic relay1of the embodiment has the joining surfaces22aand50aof the fixed terminals22and the external connection terminals50which are formed parallel to the axis Ax of the shaft15. Thereby, when the external connection terminal50and the fixed terminal22are joined, it is possible to reduce a stress acting on the fixed terminal22in the axial direction of the shaft15. Therefore, when the external connection terminal50and the fixed terminal22are joined, the fixed terminal22is prevented from being displaced in the axial direction of the shaft15. Therefore, it is possible to prevent the displacement of the movable element23which comes into contact with the fixed terminal22while the magnetizing coil11is energized. Therefore, it is possible to suppress the gap Gs from changing after the gap Gs is set.

(3) The electromagnetic relay1of this embodiment includes the frame member41in an annular shape between the sealing member40and the inner cover60. In this configuration, the entire circumference of one outer edge of the frame member41and the sealing member40are joined by brazing, and the entire circumference of the other outer edge of the frame member41and the flange61of the inner cover60are joined by resistance welding.

According to this, in the case that the sealing member40is formed by an insulating material such as ceramic and the inner cover60is formed by metal, it is possible to form reliably a closed space for sealing the arc-extinguishing gas by providing the frame member41in an annular shape between the sealing member40and the inner cover60.

(4) The electromagnetic relay1of this embodiment includes an outer cover70with an insulating property. The outer cover70and the sealing member40are joined together, and the outer cover70and the sealing member40configure the outer shell of the electromagnetic relay1.

According to this, it is possible to reduce the number of components by joining both the inner cover60and the outer cover70to the sealing member40. Further, it is possible to prevent the electromagnetic relay1and external electrical components from being short circuited by forming both the outer cover70and the sealing member40from an insulating material.

(5) In the method for manufacturing the electromagnetic relay1of the present embodiment, the Gap Gs is adjusted when the drive unit10and the relay unit20are fixed by press-fitting the recess portions32provided in the frame21and the claw portions31provided in the yoke13. The electromagnetic relay1, which accommodates the drive unit10and the relay unit20in the closed space, is formed by joining the external connection terminal50fixed to the sealing member40and the fixed terminal22, and joining the sealing member40and the inner cover60, after the above process. Therefore, since a process which may apply stress on the drive unit10or the relay unit20after adjusting the gap Gs is only a joining process for the external connection terminal50and the fixed terminal22, it is possible to suppress changing of the gap Gs. Therefore, according to the method for manufacturing the electromagnetic relay1, it is possible to reduce differences of the gap Gs for each product in a configuration in which the drive unit10and the relay unit20are accommodated in the closed space in which the arc extinguishing gas is sealed.

(6) In the method for manufacturing the electromagnetic relay1of the present embodiment, the method of joining the external connection terminal50and the fixed terminal22is designed to be a method in which a thermal stress or a mechanical stress acting on the fixed terminal22ais small as compared with a thermal stress or a mechanical stress acting on the external connection terminal50.

Therefore, when the external connection terminal50and the fixed terminal22are joined, the fixed terminal22is prevented from being displaced in the axial direction of the shaft15. Therefore, it is possible to suppress the gap Gs from changing after the gap Gs is set.

(7) In the method of manufacturing the electromagnetic relay1of the present embodiment, the inner cover60and the sealing member40are joined via the frame member41. That is, it is employed a method in which the entire circumference of one outer edge of the frame member41and the sealing member40are joined by brazing, and then the entire circumference of the other outer edge of the frame member41and the inner cover60are joined by seam welding.

According to this, in the case that the sealing member40is formed by an insulating material such as ceramic and the inner cover60is formed by metal, it is possible to form reliably a closed space for sealing the arc-extinguishing gas by providing the frame member41between the sealing member40and the inner cover60.

(8) The manufacturing method of the electromagnetic relay1of the present embodiment includes a process of configuring the outer shell of the electromagnetic relay1by the outer cover70and the sealing member40by joining the outer cover70with an insulating property covering the inner cover60and the sealing member40.

According to this, it is possible to reduce the number of components by joining both the inner cover60and the outer cover70to the sealing member40. Further, it is possible to prevent the electromagnetic relay1and external electrical components from being short circuited by forming both the outer cover70and the sealing member40from an insulating material.

Other Embodiments

The disclosure in the specification is not limited to the above described embodiments and may be suitably modified within a scope described in claims.

(1) For example, the gap Gs may be adjusted by adjusting a press-fitting amount of the insulating terminal18into the shaft15.

(2) In the above embodiment, although the frame member41is arranged between the sealing member40and the inner cover60, not limited to the above, the frame member41may be eliminated and the sealing member40and the inner cover60may be directly joined. In this case, the sealed space sealing the arc-extinguishing gas is formed by the sealing member40and the inner cover60.

(3) In the above embodiment, although the insulating outer cover70is provided outside the inner cover60, not limited to the above, the outer cover70may be eliminated.

Further, in each of the above-mentioned embodiments, it goes without saying that components of the embodiment are not necessarily essential except for a case in which the components are particularly clearly specified as essential components, a case in which the components are clearly considered in principle as essential components, and the like. Further, in each of the embodiments described above, when numerical values such as the number, numerical value, quantity, range, and the like of the constituent elements of the embodiment are referred to, except in the case where the numerical values are expressly indispensable in particular, the case where the numerical values are obviously limited to a specific number in principle, and the like, the present disclosure is not limited to the specific number. Furthermore, a shape, positional relationship or the like of a structural element, which is referred to in the embodiments described above, is not limited to such a shape, positional relationship or the like, unless it is specifically described or obviously necessary to be limited in principle.