JP2009129878A - Electromagnetic relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic relay 1 which is blown out to shut down a current only when the electromagnetic relay 1 itself gets a flow of an excess current and which has a small size and has a high setting flexibility for a blowing out current. <P>SOLUTION: The electronic relay is provided with a pair of fixed contact points 6 electrically connected with an electric circuit with tow terminal bolts 4 in-between, a movable contact point 7 movable in accordance with the pair of the fixed contact points 6, a contact point pressure spring 8 for pushing down the movable contact point 7 on the fixed contact point 6, a switch portion 2 composed of a switch cover 9 or the like for housing all the above components, a solenoid portion 3 in which a fixed iron core 22 and a movable iron core 23 are mounted in an exciting coil 20 wound over a resin-make bobbin 26 with a return spring 24 in-between, and a rod 18 is pinched and assembled between the movable iron core 23 and the movable contact point 7, and furthermore, the movable contact point 7 is made of a brass material of a low melting point and an appropriate conductive cross-sectional area is set so that a Joule heat can be generated to reach a melting point in an excess current area. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic relay for intermittently energizing an electric load.

[Conventional technology]
Conventionally, an electromagnetic relay is preferably used for energizing each electric load that is used with a relatively large current, such as a vehicle-mounted heater or motor, and is used by configuring an electric circuit as shown in FIG. ing.

  The electromagnetic relay is an exciting coil that generates a magnetic force when energized, a fixed iron core, a yoke, a movable iron core as a magnetic member that converts this magnetic force into an attractive force, and returns the movable iron core to its initial position when the magnetic force disappears. There is an electromagnetic relay comprising a solenoid part having a return spring and a contact type switch part insulated and fixed above the solenoid part (see, for example, Patent Document 1).

When the exciting coil is energized, a magnetic force is generated, the movable iron core is attracted to the fixed iron core, a stroke is generated, and the movable contact of the switch unit comes into contact with the fixed contact, thereby energizing the electric load. At this time, when the electric load is, for example, a motor or the like, a large inrush current flows when the contact is closed, but the motor or the like normally operates as an electric load of the electric circuit.
JP 2005-56690 A

  However, in an electric circuit that flows a large current or an electric load that generates a large inrush current, a fuse that can be easily blown cannot be set. For example, an excessive current when a vehicle abnormality occurs may cause a vehicle malfunction. It is considered that the nature is high. If an extremely large current flows through the electrical circuit during actual operation of the electromagnetic relay due to some abnormality on the vehicle side, the wire used in the circuit may generate heat and burn out beyond the heat resistance limit of the wire. In addition, there is a possibility that the electromagnetic relay itself may malfunction due to heat generated in the terminal portion.

  In addition, if an excessive current flows to the electrical load due to an abnormality, a fuse is provided on the electrical load side to prevent damage to the electrical load side. Can be difficult and mismatched. In addition, the structure may become complicated and large due to the large current.

  Therefore, the object of the present invention has been made in view of the above problems, and when the electromagnetic relay itself flows excessively, the current is cut off to cut off the current. It is to provide a high electromagnetic relay.

[Means of Claim 1]
According to the first aspect of the present invention, the bottomed cylindrical yoke, the cylindrical excitation coil housed in the yoke, the fixed iron core disposed in the inner space of the excitation coil, and the fixed iron core are movable opposite to each other. A solenoid part including a movable iron core and a return spring that urges the movable iron core in an anti-fixed iron core direction, a rod fixed to the axial center of the movable iron core, and an opening of the yoke are sealed in the axial direction. A cover forming a working chamber, a pair of terminal through holes formed on both sides of the working chamber, a set of terminal portions penetrating through the terminal through holes, and a tip facing the cover forming a fixed contact; A movable contact that is inserted into the chamber and is pushed by a rod and faces a position away from the fixed contact; and a contact pressure spring that is disposed in a compressed state in the working chamber and biases the movable contact toward the fixed contact. In an electromagnetic relay consisting of a switch part, The fixed contact is formed by joining the fixed contact tip and the fixed base, the fixed base is integrated with the terminal portion or joined separately, and the movable contact is formed by joining the movable contact tip and the movable base. The movable base metal is characterized by being made of a material having a melting point lower than that of the terminal portion and each contact chip.

  As a result, a fusing structure at a desired location can be established by the combination of the respective constituent materials constituting the one set of terminal portion, fixed contact, and movable contact, so that a desired current value can be obtained without causing a mismatch. Can be prevented, and damage to the electric circuit can be reliably prevented. In addition, since it is possible to add parts without changing the structure, simplification and miniaturization can be realized.

[Means of claim 2]
According to the second aspect of the present invention, the constituent material of the movable base metal of the movable contact is brass.
As a result, the normal movable contact is a structure that uses a movable base made of brass, and the melting point of brass is lower than that of other components. Can be configured.

[Means of claim 3]
According to the third aspect of the present invention, the energizing cross-sectional area of the movable contact is set so that the movable contact does not generate heat in the normal current range but has a conductor resistance value in which the Joule heat reaches the melting point in the excessive current range exceeding the maximum current used It is characterized by being.
Thereby, the electric current value which interrupts | blocks electricity supply of an electric circuit can be arbitrarily set by adjusting the electricity supply cross-sectional area of the movable base metal of a movable contact, and the freedom degree of a setting increases.

[Means of claim 4]
According to the fourth aspect of the present invention, the movable base metal of the movable contact is melted to cut off the electric circuit.
Thereby, after interruption of the electric circuit, it is possible to prevent an increase in vehicle trouble due to energizing an excessive current by re-inserting the electromagnetic relay.

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

[Configuration of Example 1]
FIG. 1 is a cross-sectional view of an electromagnetic relay in the present embodiment. 2A is a top view of the fixed contact, and FIG. 2B is a front view. FIG. 3A is a top view of the movable contact, and FIG. 3B is a front view.

  As shown in FIG. 1, the electromagnetic relay 1 is configured by assembling a switch unit 2 and a solenoid unit 3 with their axes aligned. In the following description, the axial direction of the electromagnetic relay 1 closer to the switch portion 2 is the upper side, the solenoid portion 3 closer is the lower side, and the vertical direction follows this.

  The switch unit 2 includes a set of fixed contacts 6 connected to an electric circuit (not shown) via two terminal bolts 4, a movable contact 7 that moves to face the set of fixed contacts 6, It comprises a contact pressure spring 8 that presses the contact 7 against the fixed contact 6, and a switch cover 9 that is a lid that houses these components.

  The switch cover 9 is made of an electrically insulating resin, and the working chamber 10 is formed in the central axis direction. A pair of terminal through holes 14 are provided in the upper side wall portion of the working chamber 10 in the axial direction. In addition, a contact receiving portion 13 that protrudes from the working chamber 10 is provided at a central position between the terminal through holes 14.

  The two terminal bolts 4 constitute the terminal part of the switch part 2, are made of a highly conductive iron material, penetrate the terminal through hole 14 via the O-ring 17, and are exposed to the outside of the switch cover 9. Terminal portion 30 and fixed contact 6 facing inside. The terminal portion 30 has a bolt structure in order to electrically connect wiring of an electric circuit by screwing.

  As shown in FIGS. 2A and 2B, the fixed contact 6 is configured by joining a fixed contact tip 12 to a contact surface of a fixed base 11 formed integrally with the terminal bolt 4 by brazing or the like. The Usually, the constituent material of the fixed contact tip 12 is formed of a highly conductive silver alloy, and the fixed base 11 is made of a highly conductive iron material integrated with the terminal bolt 4. The set of fixed contacts 6 is disposed horizontally at a substantially center in the working chamber 10 of the switch cover 9 with a movable contact 7 described later and a predetermined contact gap G1 therebetween (see FIG. 1).

  The fixed base 11 may be composed of a separate member from the terminal bolt 4 and may be fixed to and integrated with the end of the terminal bolt 4 by brazing or the like. Even in this case, the fixing base 11 is preferably made of an iron material like the terminal bolt 4.

  The movable contact 7 is positioned in contact with a contact receiving portion 13 projecting from the working chamber 10 inside the switch cover 9 and attached with a contact pressure spring 8 disposed around the contact receiving portion 13. Under the influence of the force, it abuts against the end face of the rod 18 fixed to the movable iron core 23 described later.

  As shown in FIGS. 3A and 3B, the movable contact 7 includes a movable base 15 which is a plate-like conductor segment made of a highly conductive metal material, and a movable contact chip 16 on both sides thereof. Formed by brazing the parts in pairs. Usually, the constituent material of the movable contact tip 16 is formed of a silver alloy like the fixed contact tip 12 of the fixed contact 6, and the constituent material of the movable base metal 15 is preferably brass. In addition, an R (R) notch for narrowing the energization cross-sectional area at the center in the longitudinal direction of the movable contact 7 so that the conductor resistance value between the movable contact chips 16 of the movable contact 7 becomes a predetermined resistance value. Has been processed.

  In this embodiment, as shown in FIG. 3C, the energization cross-sectional area is reduced by increasing the R notch in the width direction to reduce the energization cross-sectional area. In addition, the energization cross-sectional area may be adjusted by denting the R notch in the thickness direction without being limited to the width direction of the movable base metal 15.

  On the other hand, the solenoid unit 3 has a known structure including a yoke 19, an exciting coil 20, a ground plate 21, a fixed iron core 22, a movable iron core 23, a return spring 24, and the like, which will be described in detail below.

  As shown in FIG. 1, the yoke 19 is provided in a bottomed cylindrical shape having a thin upper portion and an opening, and a lower bottom portion having a thick bottom portion. Also serves as a case. Moreover, the yoke 19 is made of soft iron, and ensures a magnetic path and rigidity suitably. Further, a thin portion 25 having a small thickness is provided on the outer surface of the opening portion of the yoke 19, and a caulking allowance for assembly with the switch portion 2 is provided.

  The exciting coil 20 is wound around a resin bobbin 26 and accommodated inside the yoke 19. The upper end of the bobbin 26 is formed with a flange portion 27 protruding radially outward. The ground plate 21 is insert-molded into the flange portion 27 and is inserted into the lower step of the thin portion 25 of the yoke 19. It is sandwiched and fixed between the lower end portion of the switch cover 9. Thereby, the axial positioning of the exciting coil 20 is performed.

  The fixed iron core 22 is a cylindrical magnetic member made of soft iron, is attached to the inner periphery of the exciting coil 20, and its lower end is fixed to the yoke 19. Further, a stepped portion having a diameter different from that of the outer periphery is formed on the upper outer periphery of the fixed iron core 22 so as to hold a return spring 24 described later.

  The movable iron core 23 is a soft magnetic columnar magnetic member that is slidably accommodated with the inner periphery of the exciting coil 20. A concave portion 28 is formed on the upper end surface of the movable iron core 23, and a rod 18 to be described later is fixed thereto. Further, a stepped portion is formed on the lower outer periphery and engages with the return spring 24. When the exciting coil 20 is not energized, the movable iron core 23 has an upper end surface that protrudes slightly above the ground plate 21 to suitably constitute a magnetic circuit.

  The return spring 24 is a compression coil spring, and is inserted into a gap between the stepped portion of the fixed iron core 22 and the stepped portion of the movable iron core 23. When the excitation coil 20 is not energized, the return spring 24 is attached to the upper side. A predetermined suction gap G2 is formed and held.

  In addition, an electrically insulating rod 18 made of resin is fixed to the recess 28 of the movable core 23, and the rod 18 moves up and down integrally with the movable core 23. When not energized, the movable spring 7 is in contact with the urging force of the return spring 24.

  A switch cover 9 that accommodates the movable contact 7 and the fixed contact 6 is inserted into the yoke 19 after the components of the solenoid unit 3 are incorporated into the yoke 19, and is attached to the thin portion 25 of the yoke 19. The electromagnetic relay 1 is completed by caulking and fixing via the O-ring 29.

[Operation of Example 1]
The operation of the electromagnetic relay 1 of this embodiment will be described with reference to FIG. 4A and 4B are diagrams for explaining the operation of the electromagnetic relay 1. FIG. 4A is a state when the energization is OFF (contact open state), FIG. 4B is a closing transient state immediately after the energization is turned ON, and FIG. Indicates the state.
When the power is turned off as shown in FIG. 4A, the movable iron core 23 constituting a part of the magnetic circuit does not generate a magnetic force, and is simply pushed upward by the urging force of the mechanical return spring 24 to move. The movable contact 7 abutted against the rod 18 fixed to the iron core 23 is pressed against the contact receiving portion 13 and remains in the open state in which the contact gap G1 is held between the fixed contact 6 and the movable contact 7.

  When the energization is ON as shown in FIG. 4B, a magnetic force is generated in the energized exciting coil 20, and an attractive force acts between the fixed iron core 22 and the movable iron core 23 constituting a part of the magnetic circuit. The movable iron core 23 is attracted toward the fixed iron core 22 against the urging force of the return spring 24, starts moving (stroke), and approaches the end surface of the fixed iron core 22. At this time, as shown in FIG. 4A, the suction gap G2 between the fixed iron core 22 and the movable iron core 23 when not energized is slightly larger than the contact gap G1 between the fixed contact 6 and the movable contact 7. Set to That is, since the overstroke S of the movable iron core 23 is set, the fixed contact 6 and the movable contact 7 come into contact with each other before the movable iron core 23 is attracted to the fixed iron core 22 as a transient state immediately after energization. A current starts to flow through the fixed contact 6, thereby starting the electric circuit.

  At this time, the suction force of the movable iron core 23 increases as the suction gap G2 is reduced, so that the stroke advances until the movable iron core 23 is attracted more and is attracted to the end face of the fixed iron core 22. At this time, the closing between the contacts is already performed while being in unstable contact, but a gap corresponding to the overstroke S is generated between the overstroke S and the rod 18 that contacts and presses the movable contact 7. Since the movable contact 7 and the rod 18 can be detached, stable contact between the contacts is realized by the urging force of the contact pressure spring 8 thereafter. Thereby, the closing between the contacts is stably completed, and a predetermined current flows in the electric circuit (see FIG. 4C).

  At this time, when an extremely large excessive current flows in the electric circuit due to some abnormality on the vehicle side, in the electromagnetic relay 1, the excessive current flows from one of the pair of terminal bolts 4 to the fixed contact 6, and It flows to the movable contact 7 via the fixed contact chip 12 and the movable contact chip 16 that come into contact with each other, and further passes through the movable base 15 having a predetermined energization cross-sectional area. It flows to the other terminal bolt 4 between the chip 16 and the fixed contact chip 12 and via the fixed contact 6.

  At this time, the constituent members of the switch unit 2 of the electromagnetic relay 1 are all made of a highly conductive metal material, but only the movable base 15 of the movable contact 7 is a metal material having a low melting point, for example, a brass material. Set an appropriate current-carrying cross-sectional area so that the Joule heat reaches the melting point in the overcurrent region that exceeds the maximum operating current without generating heat at the rated current that is normally used. Therefore, the excessive current is interrupted by fusing the R notch portion of the movable contact 7.

  In the configuration of this embodiment, the set of terminal bolts 4 is made of iron, each fixed contact tip 12 and each movable contact tip 16 are made of silver alloy, and the movable base 15 of the movable contact 7 is made of brass. The melting point of each constituent material is about 1530 ° C. for iron, about 960 ° C. for silver alloy, and about 900 ° C. for brass. Brass is the lowest in terms of melting point, and the current cross-sectional area is set appropriately. The movable base metal 15 that can be used is adopted. Therefore, fusing always starts at the R notch portion of the brass movable base 15 and without setting mismatch. In other words, since the two conditions of the melting point and the current cross-sectional area can be suitably set, it is easy to adjust the current at which the movable base 15 is melted with certainty while obtaining a relatively large margin. There is.

[Effect of Example 1]
In the present embodiment, a set of fixed contacts 6 connected to an electric circuit via two terminal bolts 4, a movable contact 7 that is movable facing the set of fixed contacts 6, and the movable contact 7 The fixed iron core 22 and the movable iron core are placed in the contact pressure spring 8 that presses against the fixed contact 6, the switch portion 2 including the switch cover 9 and the like for housing these components, and the exciting coil 20 wound around the resin bobbin 26. 23, the electromagnetic solenoid 3 to be mounted via the return spring 24, and the rod 18 between the movable iron core 23 and the movable contact 7 are assembled, and the movable contact 7 is made of a brass material having a low melting point. As it was used, an appropriate cross-sectional area was set so that Joule heat reaching the melting point was generated in the excessive current region.

  Accordingly, when the rated current for normal use does not generate heat, the electric circuit is normally operated (started), and when an extremely large overcurrent flows to the electric circuit due to some abnormality on the vehicle side, the movable contact 7 is melted, Overcurrent can be cut off. In addition, it is possible to cut off at the desired fusing location and current value by combining the constituent materials of the current-carrying members and setting the appropriate current-carrying cross-sectional area. Circuit damage can be prevented. Further, since it can be easily performed without adding parts or changing the structure, simplification and miniaturization can be achieved.

(Example 1) which is sectional drawing of an electromagnetic relay. (A) is a top view of a fixed contact, (b) is a front view (Example 1). (A) is a top view of a movable contact, (b) is a front view (Example 1). It is operation | movement explanatory drawing of an electromagnetic relay, (a) is at the time of energization OFF (contact opening state), (b) is the closing transient state immediately after energization ON, (c) shows the closing completion state of energization ON (Implementation) Example 1). An electric circuit diagram is shown (conventional example).

Explanation of symbols

1 Electromagnetic relay 2 Switch part 3 Solenoid part 4 Terminal bolt (terminal part)
6 fixed contact 7 movable contact 8 contact pressure spring 9 switch cover (cover)
DESCRIPTION OF SYMBOLS 10 Working chamber 11 Fixed base 12 Fixed contact tip 14 Terminal through-hole 15 Movable base 16 Movable contact tip 18 Rod 19 Yoke 20 Excitation coil 22 Fixed iron core 23 Movable iron core 24 Return spring

Claims (4)

A cylindrical yoke with a bottom, a cylindrical excitation coil accommodated in the yoke, a fixed iron core disposed in an inner space of the excitation coil, a movable iron core movable opposite to the fixed iron core, and the movable A return spring that urges the iron core in the anti-fixed iron core direction, and a solenoid part,
A rod fixed to the axial center of the movable core;
A cover that seals the opening of the yoke and forms a working chamber in the axial direction, and a pair of terminal through holes are formed on both sides of the working chamber. A pair of terminal portions whose leading ends form a fixed contact, a movable contact that is fitted into the working chamber and is pushed by the rod and faces away from the fixed contact, and is compressed in the working chamber. A contact pressure spring provided to bias the movable contact in the direction of the fixed contact;
In an electromagnetic relay consisting of
The fixed contact is formed by joining a fixed contact tip and a fixed base,
The fixed base is integral with the terminal portion or joined separately.
The movable contact is formed by joining a movable contact chip and a movable base.
The movable base is made of a material having a melting point lower than that of the terminal portion and each of the contact chips. The electromagnetic relay according to claim 1,
An electromagnetic relay characterized in that the movable base metal of the movable contact is made of brass. The electromagnetic relay according to claim 1 or 2,
The movable contact is
An electromagnetic relay characterized in that an energization cross-sectional area is set so that Joule heat reaches a conductor resistance value that reaches a melting point in an excessive current region that is greater than or equal to the maximum current that is used, in a current region that is normally used. The electromagnetic relay according to any one of claims 1 to 3,
The electromagnetic relay characterized in that the movable base metal of the movable contact is melted to cut off an electric circuit.

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