JP2009224116A - Electromagnetic switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic switch 1 capable of preventing disconnection of an attraction coil 3a due to external vibration and reducing a cost required for a winding facility. <P>SOLUTION: An electromagnetic coil 3 is constituted of the attraction coil 3a which generates an attraction force to attract a plunger 5 in order to close-operate a main contact and a retaining coil 3b which generates a holding force to hold the attracted plunger 5 in order to maintain the closed state of the main contact. The attraction coil 3a and the retaining coil 3b are respectively formed of an aluminum wire, and both the wire diameters are set to be same. Thereby, compared with the conventional attraction coil using a copper wire, vibration movement itself of the attraction coil 3a using the aluminum coil can be suppressed, and the mass of the coil terminal part becomes about a half of that of the attraction coil using copper wire, thus, even under a situation where a severe external vibration is received, stress due to vibration can be greatly reduced and durability is improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic switch for opening and closing a main contact provided in a motor circuit of a starter.

As a conventional technique, there is an electromagnetic switch disclosed in Patent Document 1.
This electromagnetic switch has a suction coil for generating a suction force for sucking the plunger and a holding coil for generating a holding force for holding the sucked plunger, and the wire diameters of the suction coil and the holding coil are substantially reduced. In order to make it the same, a copper wire is used for the suction coil and an aluminum wire is used for the holding coil.
JP-A-62-202435

However, when the electromagnetic switch described in Patent Document 1 is subjected to severe external vibration because the specific gravity of the copper wire used for the suction coil is larger than the aluminum wire used for the holding coil. In addition, the suction coil may vibrate and break.
In addition, since the coil material (copper) used for the suction coil is different from the coil material (aluminum) used for the holding coil, two types of coil wires are used when winding the suction coil and holding coil on the bobbin. (Copper wire and aluminum wire) had to be prepared, and there was a problem that the cost required for the winding equipment increased.
The present invention has been made based on the above circumstances, and an object of the present invention is to provide an electromagnetic switch that can prevent disconnection of the suction coil due to external vibration and can reduce the cost required for the winding equipment.

(Invention of Claim 1)
The present invention includes an electromagnetic coil that forms an electromagnet when energized, a fixed iron core that is magnetized by a magnetic flux generated by the electromagnet, and a plunger that is attracted and moved by the fixed iron core when the electromagnet is formed by energizing the electromagnetic coil. An electromagnetic switch that opens and closes a main contact provided in the motor circuit of the starter in conjunction with the movement of the plunger, and the electromagnetic coil generates a suction force that attracts the plunger to close the main contact The suction coil and the holding coil that generates a holding force for holding the plunger to maintain the closed state of the main contact are formed, and the suction coil and the holding coil are each formed of an aluminum wire. .

  According to said structure, disconnection of the suction coil by external vibration can be prevented by using an aluminum wire for both a suction coil and a holding coil. That is, when the aluminum wire used in the suction coil of the present invention and the copper wire used in the conventional suction coil are designed to have the same resistance value, the cross-sectional area of the aluminum wire is about 1. Since it becomes 6 times, the movement of the vibration of the suction coil using the aluminum wire can be suppressed when subjected to severe external vibration compared to the suction coil using the copper wire. Moreover, since the specific gravity of the aluminum wire with respect to the copper wire is 0.3 times, the mass of the coil terminal portion is approximately half that of the suction coil using the copper wire (1.6 × 0). .3 = 0.48). As a result, even under conditions of severe external vibration, stress due to vibration can be greatly reduced, and durability is improved.

(Invention of Claim 2)
The electromagnetic switch according to claim 1, wherein the wire diameter of the aluminum wire used for the suction coil and the wire diameter of the aluminum wire used for the holding coil are the same.
In this case, when winding the suction coil and the holding coil around the bobbin, it is not necessary to change the setup from the suction coil to the holding coil. In other words, since both the suction coil and the holding coil are made of aluminum wire and the wire diameters of both are the same, there is no need to change the setup when the suction coil is wound around the bobbin and then transferred to the holding coil. The bobbin can be continuously wound from the suction coil to the holding coil, and the workability of the winding process is improved.
Moreover, since it is not necessary to prepare two types of coil wires (copper wire and aluminum wire), the cost required for the winding equipment can be reduced.

(Invention of Claim 3)
The present invention includes an electromagnetic coil that forms an electromagnet when energized, a fixed iron core that is magnetized by a magnetic flux generated by the electromagnet, and a plunger that is attracted and moved by the fixed iron core when the electromagnet is formed by energizing the electromagnetic coil. An electromagnetic switch that opens and closes a main contact provided in the motor circuit of the starter in conjunction with the movement of the plunger, and the electromagnetic coil includes a suction force that sucks the plunger to close the main contact, In order to maintain the contact closed state, a holding force for holding the plunger is generated by one coil, and the one coil is formed of an aluminum wire.

  According to said structure, the disconnection of the electromagnetic coil by external vibration can be prevented by using an aluminum wire for an electromagnetic coil. In other words, if the resistance value of both the aluminum wire is used for the electromagnetic coil and the copper coil is used for the electromagnetic coil, the cross-sectional area of the aluminum wire is about 1. Since it becomes 6 times, when it receives severe external vibration, compared with the electromagnetic coil when using a copper wire, the movement of the vibration of the electromagnetic coil when using an aluminum wire can be suppressed. Moreover, since the specific gravity of the aluminum wire with respect to the copper wire is 0.3 times, the mass of the coil terminal portion is approximately half that of the electromagnetic coil using the copper wire (1.6 × 0). .3 = 0.48). As a result, even under conditions of severe external vibration, stress due to vibration can be greatly reduced, and durability is improved.

  The best mode for carrying out the present invention will be described in detail with reference to the following examples.

FIG. 1 is a cross-sectional view of the electromagnetic switch 1.
The electromagnetic switch 1 according to the present embodiment includes a switch case 2, an electromagnetic coil 3, a fixed iron core 4, a plunger 5, and the like described below, and is provided with a main contact (described later) provided in a motor circuit of a starter (not shown). Open and close and drive a shift lever (not shown) to push out the starter pinion gear to the engine side.
The switch case 2 is provided in a cylindrical shape having an annular bottom surface, and forms a magnetic circuit for passing a magnetic flux generated by energizing the electromagnetic coil 3.
When a start switch (not shown) is closed, the electromagnetic coil 3 is energized from the in-vehicle battery to form an electromagnet. A detailed description of the electromagnetic coil 3 will be described later.

The fixed iron core 4 is formed of a ferromagnetic material (for example, iron) that is magnetized by the magnetic flux generated by the electromagnet, and forms a magnetic circuit together with the switch case 2. The fixed iron core 4 is composed of a core portion 4a disposed to face the plunger 5 and a disk portion 4b that holds the core portion 4a. The core portion 4 a is provided in an annular body having a circular hole formed in the central portion in the radial direction, and is disposed on the inner periphery of the sleeve 6 that fits on the inner periphery of the electromagnetic coil 3. The disc portion 4b is disposed on the inner periphery of the switch case 2 on the opposite bottom side (opening portion side), and the outer diameter portion of the disc portion 4b is positioned in contact with the step formed on the inner periphery of the switch case 2. ing.
The plunger 5 is inserted into the inner periphery of the sleeve 6 and is urged toward the anti-core part direction (left direction in the drawing) by a return spring 7 disposed between the plunger 5 and the core part 4a. The plunger 5 is assembled with a shift rod 8 connected to the shift lever.

The main contact is connected to the high potential side (battery side) of the motor circuit via the B terminal bolt 9 and to the low potential side (motor side) of the motor circuit via the M terminal bolt 11. The M fixed contact 12 and the movable contact 13 that electrically connects and disconnects both the fixed contacts 10 and 12, and the movable contact 13 abuts on both the fixed contacts 10 and 12 and both the fixed contacts 10 and 12 are connected. The main contact is closed by conducting the gap, and the movable contact 13 is separated from the fixed contacts 10 and 12 and the conduction between the fixed contacts 10 and 12 is cut off, so that the main contact is opened.
The B terminal bolt 9 and the M terminal bolt 11 are fixed to a resin contact cover 14, and a B fixed contact 10 and an M fixed contact 12 are provided inside the contact cover 14.

The movable contact 13 is slidably attached to a rod 15 fixed to the plunger 5 via an insulating member 16, and the tip of the rod 15 is contacted by a contact pressure spring 17 disposed between the plunger 5 and the insulating member 16. It is urged (right direction in the figure). A washer 18 is caulked and fixed to the end of the rod 15, and the movable contact 13 is prevented from coming off the rod 15 by the washer 18.
The contact cover 14 is provided in a bottomed shape having a cylindrical leg portion 14 a, the outer periphery of the leg portion 14 a is fitted to the inner periphery of the switch case 2, and the tip surface of the leg portion 14 a is a disk of the fixed iron core 4. A part or the entire circumference of the leg part 14 a is caulked and fixed to the opening end part of the switch case 2.

Here, the electromagnetic coil 3 will be described.
The electromagnetic coil 3 includes a suction coil 3a that generates a suction force that sucks the plunger 5 in order to close the main contact, and a holding force that holds the attracted plunger 5 in order to maintain the closed state of the main contact. And is wound around the resin bobbin 19 in a two-layer state.
The suction coil 3a has one end connected to an energization terminal (not shown) fixed to the contact cover 14, and the other end connected to an M terminal bolt via a connection terminal (not shown). 11 is electrically connected.

One end of the holding coil 3b is connected to the energizing terminal together with one end of the suction coil 3a, and the other end is electrically connected to the ground side (for example, the disk portion 4b of the fixed iron core 4). And mechanically connected.
The energization terminal is sometimes called, for example, a 50 terminal, and is connected to a start switch (not shown) via a starter relay (not shown). When the start switch is turned on, the current flowing from the battery is supplied to the energization terminal via the starter relay.
By the way, the attraction coil 3a and the holding coil 3b are each formed by an aluminum wire using aluminum as a coil material, and the wire diameters of both are set to be the same.

Next, the operation of the electromagnetic switch 1 will be described.
When an electromagnet is formed by energizing the attracting coil 3a and the holding coil 3b from the battery by turning on the start switch, an attracting force is generated between the plunger 5 and the fixed iron core 4, and the attracting force is received. The plunger 5 moves to the fixed iron core 4 side. Thereby, the rod 15 fixed to the plunger 5 is pushed out, and the movable contact 13 supported by the end of the rod 15 comes into contact with the B fixed contact 10 and the M fixed contact 12. Thereafter, the plunger 5 further moves while pressing and contracting the contact pressure spring 17, and comes into contact with the end face of the core portion 4 a and stops. As a result, the reaction force stored in the contact pressure spring 17 is applied to the movable contact 13, and the movable contact 13 is pressed against the pair of fixed contacts 10 and 12, thereby closing the main contact.
When the main contact is closed, the suction coil 3a is short-circuited by the main contact. That is, no current flows through the suction coil 3a, and the plunger 5 is held in a state of being sucked only by the magnetic force (holding force) generated by the holding coil 3b.

  When the start switch is turned off after the engine is started and the main contact is closed, a current flows in series from the battery through the suction coil 3a and the holding coil 3b via the main contact. That is, a current flows through the suction coil 3a in the direction opposite to that when the plunger 5 is sucked. As a result, the magnetic force of the holding coil 3b is canceled out by the magnetic force of the attracting coil 3a and the holding force for holding the plunger 5 disappears, so that the plunger 5 receives the reaction force of the return spring 7 and is shown in FIG. It is pushed back to the rest position. As a result, the movable contact 13 is separated from the set of fixed contacts 10 and 12, and the main contact is opened.

(Effect of Example 1)
In the electromagnetic switch 1 of the present embodiment, the suction coil 3a and the holding coil 3b are each formed of an aluminum wire, so that disconnection of the suction coil 3a due to external vibration can be prevented. That is, when the aluminum wire used in the suction coil 3a of this embodiment and the copper wire used in the conventional suction coil are designed to have an equivalent resistance value, the cross-sectional area of the aluminum wire is about the cross-sectional area of the copper wire. Since it becomes 1.6 times, when it receives severe external vibration, the movement of vibration itself of the suction coil 3a using the aluminum wire can be suppressed as compared with the suction coil using the copper wire. Moreover, since the specific gravity of the aluminum wire with respect to the copper wire is 0.3 times, the mass of the coil terminal portion is approximately half that of the suction coil using the copper wire (1.6 × 0.3 = 0.48). As a result, even under conditions of severe external vibration, stress applied to the coil terminal portion by vibration can be significantly reduced, so that disconnection of the suction coil 3a can be prevented and durability is improved.

  Furthermore, since the wire diameter of the aluminum wire used for the suction coil 3a and the wire diameter of the aluminum wire used for the holding coil 3b are the same, when winding the suction coil 3a and the holding coil 3b around the bobbin 19, In addition, it is not necessary to replace the suction coil 3a with the holding coil 3b. That is, since both the suction coil 3a and the holding coil 3b are aluminum wires and the wire diameters of both are the same, the changeover is performed when the suction coil 3a is wound around the bobbin 19 and then transferred to the holding coil 3b. Since the same aluminum wire can be continuously wound around the bobbin 19 from the suction coil 3a to the holding coil 3b, the workability of the winding process is improved. Moreover, since it is not necessary to prepare two types of coil wires (copper wire and aluminum wire), the cost required for the winding equipment can be reduced.

  Further, the other end of the holding coil 3b connected to the ground can be directly welded to the iron fixed iron core 4, for example. In this case, since the difference in ionization tendency between aluminum and iron is small, corrosion due to joining of dissimilar metals can be prevented. The fixed iron core 4 may be subjected to, for example, Zn plating so that the ionization tendency with aluminum becomes small.

FIG. 2 is a side view including a partial cross section of the starter 20.
The electromagnetic switch 1 of the present embodiment is an example in which the electromagnetic coil 3 is formed of one coil. As shown in FIG. 2, the electromagnetic coil 3 has one end connected to the energizing terminal 21 and the other end connected to the switch case or the fixed iron core. That is, the electromagnetic coil 3 according to the present embodiment has a single coil that has a suction force for sucking the plunger 5 to close the main contact and a holding force for holding the plunger 5 to maintain the closed state of the main contact. It has occurred. The electromagnetic coil 3 is formed of an aluminum wire.
2 includes a motor 22 that generates a rotational force on an armature (not shown), a planetary gear reduction device 23 that reduces the rotation of the armature, and an output of the reduction device 23 is unidirectional. An output shaft 25 that is transmitted via the clutch 24, a pinion gear 26 that fits a helical spline on the outer periphery of the output shaft 25, and the like are provided on the outer periphery of the output shaft 25 via the shift lever 27 by the action of the electromagnetic switch 1. The pinion gear 26 is pushed out in the counter-motor direction (left direction in the figure), and the pinion gear 26 is engaged with the ring gear 28 of the engine.

  In the electromagnetic switch 1 shown in the second embodiment, disconnection of the electromagnetic coil 3 due to external vibration can be prevented. In other words, if the resistance value of both the aluminum coil is used for the electromagnetic coil 3 and the copper coil is used for the electromagnetic coil 3, the cross-sectional area of the aluminum wire is equal to the cross-sectional area of the copper wire. Because it is about 1.6 times larger than that of the electromagnetic coil 3 when using a copper wire, it suppresses the movement of the vibration of the electromagnetic coil 3 when using an aluminum wire when subjected to severe external vibration. it can. Moreover, since the specific gravity of the aluminum wire with respect to the copper wire is 0.3 times, the mass of the coil terminal portion is approximately half that of the electromagnetic coil using the copper wire (1.6 × 0.3 = 0.48). As a result, even under conditions of severe external vibration, stress applied to the coil terminal portion due to vibration can be significantly reduced, so that disconnection of the electromagnetic coil 3 can be prevented and durability is improved.

(Modification)
In the first embodiment, an example is described in which the wire diameters of the aluminum wires used for the suction coil 3a and the holding coil 3b are set to be the same, but the wire diameters of both may be different.

(Example 1) which is sectional drawing of an electromagnetic switch. (Example 2) which is a side view including the partial cross section of a starter.

Explanation of symbols

1 Electromagnetic Switch 3 Electromagnetic Coil 3a Suction Coil 3b Holding Coil 4 Fixed Iron Core 5 Plunger 10 B Fixed Contact (Main Contact)
12 M fixed contact (main contact)
13 Movable contact (main contact)
20 Starter

Claims (3)

An electromagnetic coil that forms an electromagnet when energized;
A fixed iron core magnetized by the magnetic flux generated by the electromagnet,
A plunger that is attracted to and moved by the fixed iron core when the electromagnetic coil is energized to form an electromagnet;
An electromagnetic switch that opens and closes a main contact provided in the motor circuit of the starter in conjunction with the movement of the plunger,
The electromagnetic coil generates a suction force for sucking the plunger to close the main contact;
A holding coil that generates a holding force for holding the plunger in order to maintain the closed state of the main contact;
The attraction coil and the holding coil are each formed of an aluminum wire. The electromagnetic switch according to claim 1,
An electromagnetic switch characterized in that a wire diameter of an aluminum wire used for the suction coil and a wire diameter of an aluminum wire used for the holding coil are the same. An electromagnetic coil that forms an electromagnet when energized;
A fixed iron core magnetized by the magnetic flux generated by the electromagnet,
A plunger that is attracted to and moved by the fixed iron core when the electromagnetic coil is energized to form an electromagnet;
An electromagnetic switch that opens and closes a main contact provided in the motor circuit of the starter in conjunction with the movement of the plunger,
The electromagnetic coil generates a suction force for sucking the plunger for closing the main contact and a holding force for holding the plunger for maintaining the closed state of the main contact with one coil. An electromagnetic switch characterized in that one coil is formed of an aluminum wire.

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