JP2002118016A - Magnet switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and weight of a magnet switch 1 by setting the shapes of a bottom section 2a of a yoke 2 and a disk section 4 of a fixed iron core 3, so that the magnetic flux density in parts become almost uniform. SOLUTION: The thicknesses of the bottom section 2a of the yoke 2 and disk section 4 of the fixed iron core 3 are made gradually thinner, going toward their outer diameter sides starting from their inner diameter sides. Consequently, the magnetic flux density in the parts can be made almost uniform between the inner and outer diameter sections and decline in magnetic flux density in the parts can be suppressed. Therefore, the excessive thicknesses of the yoke 2 and iron core 3 can be eliminated, without lowering the attracting force which acts on a plunger shaft 8 when a coil is energized, and the size and weight of the magnet switch 1 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet switch, and is suitably used as a switch for energizing a starter motor of a starter for starting an engine.

[0002]

2. Description of the Related Art A conventional magnet switch is disclosed, for example, in Japanese Utility Model Laid-Open Publication No. 61-176751. When the coil is energized, a magnetic flux is generated as shown in FIG. The dimensions of each part are set so that the magnetic flux density of the end of the yoke and the fixed iron core becomes appropriate.

[0003]

However, in the above-described magnet switch, the axial thicknesses of the yoke bottom portion and the fixed core disk portion are made uniform. For this reason,
If the thickness is determined so that the magnetic flux density at the bottom of the yoke and the inner diameter of the fixed core disk is appropriate, the extra thickness increases from the inner diameter to the outer diameter, and the physical size of the magnet switch In addition, there is a problem that the weight increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made to realize a reduction in size and weight of a magnet switch without impairing the appropriateness of the magnetic flux density at the bottom of the yoke and the fixed core disk. With the goal.

[0005]

In order to achieve the above object, the present invention employs the following technical means.

In the magnet switch according to the first aspect of the present invention, the thickness of the inner diameter portion of at least one of the bottom portion of the yoke and the fixed core disk portion is set to be larger than the thickness of the outer diameter portion. This suppresses the decrease in magnetic flux density inside the parts, reduces the attraction force acting on the plunger shaft when the coil is energized, eliminates at least one of the extra thickness of the yoke and the fixed iron core, and reduces the size of the magnet switch. The weight can be reduced.

According to a second aspect of the present invention, there is provided a magnet switch according to the first aspect, wherein at least one of the thickness of the bottom of the yoke and the fixed core is increased from the inner diameter toward the outer diameter. Gradually thinned. As a result, the magnetic flux density inside the component is made substantially uniform between the inner diameter portion and the outer diameter portion, the decrease in the magnetic flux density inside the component is suppressed, and the yoke and fixing are performed without reducing the attractive force acting on the plunger shaft when the coil is energized. By removing at least one extra thickness of the iron core, the size and weight of the magnet switch can be reduced.

According to a third aspect of the present invention, there is provided the magnet switch according to the first aspect, wherein at least one of the bottom of the yoke and the fixed core disk has a thickness increasing from the inner diameter to the outer diameter. Stepwise thinning. This allows the magnetic flux density inside the part to be
It is made substantially uniform between the outer diameter parts, suppresses the decrease in magnetic flux density inside the part, without reducing the attractive force acting on the plunger shaft when the coil is energized, removing at least one extra thickness of the yoke and the fixed iron core, The size and weight of the magnet switch can be reduced.

A magnet switch according to a fourth aspect of the present invention is the magnet switch according to the second or third aspect, wherein at least one of the yoke bottom portion and the fixed iron disk portion has a plurality of parts. It was configured in combination. Thereby, while suppressing the rise in cost, the magnetic flux density inside the part is made substantially uniform between the inner diameter portion and the outer diameter portion,
A decrease in magnetic flux density inside the component can be suppressed. Therefore, the magnet switch is reduced in size by eliminating at least one of the excess thickness of the yoke and the fixed iron core without reducing the attractive force acting on the plunger shaft when the coil is energized.
The weight can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the magnet switch of the present invention is applied to a magnet switch of a vehicle starter will be described below with reference to an embodiment shown in the drawings.

FIG. 1 is a sectional view of a magnet switch 1 according to the present invention.

The yoke 2 is formed by processing a magnetic metal (for example, low carbon steel) into a cylindrical shape with a bottom by cold forging or the like, and has a hole 2 through which the plunger shaft 8 is inserted in the center of the bottom 2a.
b is provided. In addition, the bottom 2a has an inner diameter (hole 2).
The thickness (portion b in FIG. 1) of the bottom portion 2a is set to be larger than the thickness of the outer diameter portion, and the thickness of the bottom portion 2a is smoothly reduced from the inner diameter portion to the outer diameter portion. .

The fixed iron core 3 is made of a magnetic metal (eg, iron), and is formed integrally by press-fitting and fixing the disk portion 4 to the guide portion 5. The thickness of the inner diameter portion (the fitting portion with the guide portion 5) (the dimension in the left-right direction in FIG. 1) of the disk portion 4 is larger than the thickness of the outer diameter portion, and the thickness of the disk portion 4 is outside the inner diameter portion. It is set so as to gradually decrease toward the diameter. The guide portion 5 has a regulating portion 5a for regulating the movement of the plunger shaft 8, and a hole 5b for inserting the plunger shaft 8.

The coil 6 is formed by winding a copper wire 6b provided with an insulating film around a bobbin 6a made of resin. The coil 6 has a bottom 2 a and a disc 4 on the inner periphery of the yoke 2.
, And both end surfaces in the axial direction of the bobbin 6a are formed in shapes corresponding to the bottom portion 2a and the disk portion 4, respectively.

The sleeve 7 is formed by drawing a non-magnetic conductive metal (for example, brass, copper, aluminum, etc.) into a cylindrical shape, and is fitted on the inner periphery of the yoke 2 and the outer periphery of the guide portion 5. They are fitted together.

The plunger shaft 8 is formed of a rod-shaped magnetic metal (for example, iron) and is slidably disposed in the sleeve 7 in the axial direction (the left-right direction in FIG. 1). Further, the plunger shaft 8 has a stopper 8a on the fixed iron core 3 side. When the coil 6 is energized and attracted and moved toward the fixed iron core 3, the stopper 8a comes into contact with the restricting portion 5a of the guide portion 5 and comes into contact. Stop. A movable contact 11 is held in a small diameter portion 8b provided at the fixed iron core end of the plunger shaft 8. Further, the plunger shaft 8 is urged by a return spring 9 in a direction away from the fixed core 3 (the left side in FIG. 1).

The movable contact 11 is made of a metal plate having a small electric resistance, such as copper, and has a fixed core 3 of the plunger shaft 8.
The plunger shaft 8 is sandwiched between two insulating washers 12 and 13 attached to a small diameter portion 8b formed at the side end.
And are held electrically insulated. The insulating washers 12 and 13 are slidably held in the axial direction with respect to the small-diameter portion 8b, and are prevented from falling off by a retaining ring 14 attached to the rear end of the plunger shaft 8. The movable contact 11 is urged rightward in FIG. 1 by a contact spring 15. Since the movable contact 11 is held at the rear portion of the plunger shaft 8 in this way, the plunger shaft 8 further moves rightward in FIG. 1 in a state where the movable contact 11 contacts the fixed contacts 16 and 17. Also, the movable contact 11 is fixed
The plunger shaft 8 can move rightward in FIG.

The switch cap 10 is formed from an electrically insulating material such as a resin, and has two fixed contacts 16 and 17. The two fixed contacts 16 and 17 are movable contact 11
When the terminal is attracted by the fixed iron core 3 and moves, the switch cap 10 is a terminal made of copper or the like that conducts through the movable contact 11.
Are fixed to the switch cap 10 by washers 18 and 19 mounted from outside. Two fixed contacts 1
One of 6, 17 is connected to a positive electrode of a battery (not shown), and the other is connected to a starter motor (not shown). When the movable contact 11 comes into contact with the two fixed contacts 16 and 17, the electric circuit is closed and the starter motor rotates. The switch cap 10 is attached to the yoke 2
To the rear end 2c together with the disk 4 of the stator core 4,
The yoke 2 is attached by caulking the rear end 2c inside.

The two fixed contacts 16 and 17 are movable contact 1
When the movable core 1 is moved by being attracted to the fixed iron core 3,
A terminal such as copper that conducts through the switch cap 1
The washers 18, 19 mounted from the outside of the
It is fixed to the switch cap 10. One of the two fixed contacts 16, 17 is connected to a positive pole of a battery (not shown), and the other is connected to a starter motor (not shown). The movable contact 11 has two fixed contacts 16 and 17
, The electric circuit is closed and the starter motor rotates.

Next, a method of assembling the magnet switch 1 according to one embodiment of the present invention will be briefly described.

First, the sleeve 7 is pressed into the outer periphery of the guide portion 5 of the fixed iron core 3. Next, the return spring 9 is mounted on the guide portion 5, and then the plunger shaft 8 is inserted into the sleeve 7. At this time, the small diameter portion 8b of the plunger shaft 8 is also inserted into the hole 6b of the guide portion 5.

Next, the small diameter portion 8b of the plunger shaft 8
Is projected from the fixed iron core 3, and the contact spring 15, the washer 14, the movable contact 11, and the washer 15 are inserted into the small-diameter portion 8 b in this order. Then, the retaining ring 14 is mounted on the small diameter portion 8b, and the above-described components are slidably held by the small diameter portion 8b.

Next, the coil 6 is inserted into the outer periphery of the sleeve 7 and one end of the bobbin 6a is brought into contact with the end surface of the disk portion 4, and then the yoke 2 is inserted into the outer periphery of the coil 6 and the inside of the yoke 2 is inserted. The sleeve 7 is fitted around the circumference.

Finally, the switch cap 10 to which the two fixed contacts 16 and 17 are already fixed is inserted into the rear end portion 2c of the yoke 2 and brought into contact with the disk portion 4 of the fixed iron core 3 and then to the rear end. The switch cap 10 is fixed by swaging the portion 2c.

Thus, the assembly of the magnet switch 1 is completed.

Next, the operation of the magnet switch 1 according to one embodiment of the present invention will be described. When a starter switch (not shown) is turned on, the coil 6 is energized to generate a magnetic force, and the plunger shaft 8 is attracted toward the fixed iron core 3 against the urging force of the return spring 9. Then, the movable contact 31 at the rear end of the plunger shaft 8 comes into contact with the two fixed contacts 16 and 17, and the starter motor (not shown) is energized via the movable contact 11 to rotate. At this time, the stopper portion 8a of the plunger shaft 8 has not yet contacted the regulating portion 5a. Therefore, the plunger shaft 8 further moves and stops until the stopper portion 8a comes into contact with the regulating portion 5a. At this time, contact spring 15
Is further compressed after the movable contact 11 contacts the two fixed contacts 16 and 17. Therefore, the contact spring 15
Increases the force pressing the fixed contact 13 toward the two fixed contacts 16, 17, so that the conduction between the fixed contact 13 and the two fixed contacts 16, 17 is favorably maintained.

When the engine is started and a starter switch (not shown) is turned off, the magnetic force generated by the coil 6 disappears and the suction force disappears, and the return spring 9 moves the plunger shaft 8 away from the fixed iron core 3. I do. Then, the movable contact 11 separates from the fixed contacts 16 and 17, and the energization of the starter motor (not shown) is stopped.

Here, the magnetic force generated when the coil 6 is energized will be described.

In the magnet switch 1, in order to generate an attractive force with high efficiency, the magnetic flux density (the amount of magnetic flux per unit area) in the magnetic circuit is set to an appropriate value according to the material of the members constituting the magnetic circuit. There is a need to. When the coil 6 is energized, magnetic flux flows through a magnetic circuit composed of the yoke 2, the fixed iron core 3, and the plunger shaft 8.
In the bottom portion 2a of the yoke 2 and the disk portion 4 of the fixed iron core 3, the magnetic flux flows radially in the radial direction as shown by the arrow in FIG.

FIG. 2A is a partial sectional view of the bottom 2 a of the yoke 2. In the bottom 2a, assuming that the thickness at an arbitrary diameter d is t and the magnetic flux is Φ, the magnetic flux density B in the cylindrical cross section of the diameter d is B = Φ / (π · dt). As shown in FIG. 2A, the diameter of the inner diameter of the bottom 2a is d1, the thickness is t1, and the diameter of the outer diameter of the bottom 2a is d.
2. Since the thickness is t2, the magnetic flux density B1 at the inner diameter of the bottom 2a is B1 = Φ / (π · d1 · t1),
a The magnetic flux density B2 at the outer diameter portion is B2 = Φ / (π · d
2 · t2). Here, when the magnetic flux density of each part of the magnetic circuit is almost the same at any place, the volume of the magnetic circuit becomes the minimum value. Therefore, in the case of the embodiment, in order to make the magnetic flux density of the outer diameter portion equal to the magnetic flux density of the inner diameter portion, B
From 1 = B2, t2 = t1 × (d1 / d2). d
Since 1 <d2, (d1 / d2) <1, and t1>
t2. That is, it is understood that the thickness t1 of the inner diameter portion should be larger than the thickness t2 of the outer diameter portion.

Regarding the thickness of the disk portion 4 of the fixed iron core 3,
The same relationship as in the case of the bottom 2a is established.

On the other hand, in the conventional magnet switch 1, the thickness of the bottom portion 2a and the disk portion 4 is set so that the magnetic flux density in the inner diameter portion becomes an appropriate value, and
a and the thickness of the disk portion 4 are the same for both the inner diameter portion and the outer diameter portion. Therefore, the thickness of the outer diameter part of the bottom part 2a and the disk part 4 was unnecessarily large, and both the physique and weight of the magnet switch 1 became large.

In the magnet switch 1 according to the embodiment of the present invention described above, the thickness of the inner diameter portion of the bottom portion 2a and the disk portion 4 is set to be larger than the thickness of the outer diameter portion. This suppresses a decrease in the magnetic flux density inside the component, reduces the attraction force acting on the plunger shaft 8 when the coil 6 is energized, and eliminates at least one of the excess thickness of the yoke 2 and the fixed iron core 3 to reduce the magnet. The switch 1 can be reduced in size and weight.

FIG. 3 is a partially enlarged sectional view of a first modification of the magnet switch 1 according to one embodiment of the present invention.
In the first modified example, as shown in FIG. 3, the thickness of the bottom 2a of the yoke 2 is set so as to gradually decrease from the inner diameter to the outer diameter. This also provides the same effect as the above-described embodiment.

FIG. 4 is a partially enlarged sectional view of a second modification of the magnet switch 1 according to one embodiment of the present invention.
In this second modification, as shown in FIG.
It consists of two parts. That is, the bottom 20 formed by forging or the like of a steel material is integrated with the yoke 2 obtained by pressing a steel plate having a uniform thickness by welding or the like. This also provides the same effect as the above-described embodiment. Further, since the two parts constituting the yoke 2 can be easily processed, the size and weight of the magnet switch 1 can be reduced while suppressing the manufacturing cost.

FIG. 5 is a partially enlarged sectional view of a third modification of the magnet switch 1 according to one embodiment of the present invention.
In the third modification, as shown in FIG. 5, the yoke 2 is composed of a plurality of components. That is, discs 20a to 20d having different outer diameters, which are also formed by pressing a steel plate having a uniform thickness, are stacked on the yoke 2 obtained by pressing a steel plate having a uniform thickness in order from the bottom 2a side in order of increasing outer diameter, and welding is performed. Are integrated. This also provides the same effect as the above-described embodiment.

In the magnet switch 1 according to one embodiment of the present invention, the thickness of the inner diameter of both the bottom 2a and the disk 4 is set to be larger than the thickness of the outer diameter. The thickness may be set larger than the thickness of the outer diameter portion. This also provides the same effect as the above-described embodiment.

In the magnet switch 1 according to one embodiment of the present invention, the fixed core 3 is composed of two parts, the disk part 4 and the guide part 5, but may be formed as one part by forging or the like.

[Brief description of the drawings]

FIG. 1 is a sectional view of a magnet switch 1 according to an embodiment of the present invention.

FIG. 2A is an enlarged partial cross-sectional view of a magnet switch 1 according to one embodiment of the present invention. (B)
It is the A arrow view of (a).

FIG. 3 is a partial cross-sectional view of a first modification of the magnet switch 1 according to the embodiment of the present invention.

FIG. 4 is a partial sectional view of a second modification of the magnet switch 1 according to the embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a third modification of the magnet switch 1 according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnet switch 2 Yoke 2a Bottom part 2b hole 2c Rear end part 3 Fixed iron core 4 Disk part 5 Guide part 5a Restriction part 5b hole 6 Coil 6a Bobbin 6b Copper wire 7 Sleeve 8 Plunger shaft 8a Stopper part 8b Small diameter part 9 Return spring 10 Switch Cap 11 Movable contact 12 Insulating washer 13 Insulating washer 14 Retaining ring 15 Contact spring 16 Fixed contact 17 Fixed contact 20 Bottom 20a Bottom 20b Bottom 20c Bottom 20d Bottom

Claims (4)

[Claims] A yoke made of a cylindrical magnetic material having a bottom portion; a fixed iron core made of a magnetic material having a disk portion that covers an opening of the yoke and opposes the bottom portion; A coil that is disposed between the bottom and the fixed core and generates a magnetic force when energized, and is formed by winding a coil wire having an outer periphery covered with an insulating film in a cylindrical shape, and the yoke bottom and the fixed core. A cylindrical sleeve made of a non-magnetic metal and disposed inside the coil, and slidably disposed on the inner circumferential side of the sleeve and in the axial direction of the sleeve, and the coil is energized when the coil is energized. A magnet switch including a plunger shaft made of a magnetic material and attracted in a direction toward the disk portion of a fixed core, wherein the disk of the bottom of the yoke and the fixed core is provided. Magnetic switch, characterized in that larger than the outer diameter thickness a thickness of at least one of the inner diameter portion of the. 2. The magnet according to claim 1, wherein the thickness of at least one of the bottom portion of the yoke and the disk portion of the fixed core is gradually reduced from an inner diameter portion to an outer diameter portion. switch. 3. The apparatus according to claim 1, wherein the thickness of at least one of the bottom portion of the yoke and the disk portion of the fixed core is reduced stepwise from an inner diameter portion to an outer diameter portion. magnetic switch. 4. The device according to claim 2, wherein at least one of the bottom portion of the yoke and the disk portion of the fixed core has a thickness change portion formed by combining a plurality of components.
Or the magnet switch according to claim 3.