JP2002260512A - Magnet switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abrasion of a magnetic body 19 that increases an initial attraction force by providing a sleeve 20 made of a nonmagnetic body, and to secure a sufficient contact load by arranging the magnetic body 19 away from the fixed iron core 4, in a magnetic switch 1. SOLUTION: A sleeve 20 is arranged outside the periphery of a movable iron core slidably in the axis direction so that the movable iron core 2 and the magnetic body 19 do not directly slide against each other. Hereby, it is possible to prevent degradation of slidability of the movable iron core 2 due to the abrasion of the magnetic body 19 and failures such as an operation failure caused by a newly formed magnetic circuit due to warm powder of the magnetic body 19. Additionally, the magnetic body 19 is separated away from the fixed iron core 4 in the axis direction, and arranged so as not to lap over with the outer periphery of the movable iron core 2 in the radial direction when an exciting coil 3 is not energized. Increasing the initial attraction force by above measures, it is possible to revive the attraction fore at the air gap = 0 until the similar level without the magnetic body 19 and ensure the sufficient contact load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet switch for opening and closing contacts by electromagnetic force.

[0002]

2. Description of the Related Art The operation of a conventional magnet switch will be briefly described. First, when the excitation coil is not energized, the movable core is urged by the elastic member in a direction away from the fixed core, and is separated from the fixed core. Therefore, the movable contact arranged so as to be able to move integrally with the movable core is separated from the pair of fixed contacts arranged opposite to the movable contact. As a result, the electrical conduction between the pair of fixed contacts is interrupted, and the magnet switch is in the open state. Next, when the excitation coil is energized, the movable core is attracted to the fixed core by the magnetic force generated by the excitation coil,
It moves until it comes into contact with the fixed iron core while resisting the urging force of the elastic member. At this time, the movable contact also moves integrally with the movable iron core and contacts the pair of fixed contacts. As a result, electrical conduction is provided between the pair of fixed contacts, and the magnet switch is closed.

Meanwhile, there is a demand for improving the open / close responsiveness of a magnet switch. For this purpose, it is necessary to increase the initial attractive force of the exciting coil, that is, the attractive force when the distance (air gap) between the movable iron core and the fixed iron core is maximum.

[0004] As means for increasing the initial suction force, for example, there is one disclosed in Japanese Utility Model Laid-Open No. 153331/1986.

[0005] In this method, an annular magnetic body is provided on the inner periphery of the exciting coil from the fixed iron core toward the movable iron core, and the movable iron core is slid in the axial direction on the inner circumferential surface of the magnetic material. Is loosely fitted.

[0006]

According to this configuration, although the initial suction force can be increased, the following problems may occur. That is, since the movable iron core slides directly on the peripheral surface of the magnetic body, the magnetic body wears and the sliding resistance increases. Further, an unexpected magnetic circuit is formed by the magnetic substance wear powder, and the operation of the magnet switch is hindered. Also, when the movable core is attracted to the fixed core and moves, the magnetic body protrudes from the fixed core. Leakage of magnetic flux into the body occurs. Since the direction of the leakage magnetic flux is different from the direction of the attractive force, the attractive force is reduced as compared with the case where there is no magnetic material. In particular, when the air gap is small, the suction force is significantly reduced, and therefore the load for pressing the movable contact against the fixed contact (contact pressing load) is insufficient, and arc discharge is generated between the two contacts to damage the both contacts. Etc. may be caused.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a sleeve made of a nonmagnetic material between a magnetic material and a movable iron core to prevent wear of the magnetic material. It is to be. Still another object is to secure a sufficient contact pressing load by increasing the suction force when the air gap is small by disposing the magnetic body and the fixed iron core apart from each other.

[0008]

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, a cylindrical sleeve made of a non-magnetic material is slidably disposed on the outer periphery of the movable iron core, and the magnetic material is connected to the outer periphery of the sleeve and the inside of the exciting coil. It was arranged so as to be spaced apart from the fixed core in the axial direction with the circumference. According to this configuration, since the magnetic body does not directly contact the movable iron core, wear of the magnetic body can be prevented.
Further, when the air gap is small, the magnetic flux leaking from the movable iron core to the magnetic body can be reduced, and the pressing load of the movable contact can be sufficiently secured.

In the magnet switch according to the second aspect of the present invention, the magnetic body is arranged so that the magnetic body and the outer peripheral portion of the movable iron core do not overlap in the radial direction when the excitation coil is not energized. Thus, the initial suction force can be reliably increased.

In the magnet switch according to a third aspect of the present invention, a groove coaxial with the bobbin is provided on the outer or inner periphery of the bobbin, and a magnetic material is mounted in the groove. Thus, the magnetic body can be mounted without increasing the outer diameter of the exciting coil and increasing the size of the magnet switch.

According to a fourth aspect of the present invention, the magnetic switch is insert-molded on a bobbin. As a result, the number of steps for assembling the magnet switch can be reduced.

According to a fifth aspect of the present invention, in the magnet switch, a cylindrical sleeve made of a non-magnetic material is slidably disposed on the outer periphery of the movable iron core, the magnetic material is linear, and a bobbin is substantially formed. Insert molding was carried out over the entire length in a state of being wound coaxially with the exciting coil. According to this configuration, since the magnetic body does not directly contact the movable iron core, wear of the magnetic body can be prevented. Further, since the bobbin is reinforced by the linear magnetic material that is insert-molded in the wound state, when the exciting coil generates heat, the bobbin can be suppressed from being deformed by heat.

According to a sixth aspect of the present invention, in the magnet switch, the winding state of the linear magnetic body is composed of a loosely wound portion and a densely wound portion. The tightly wound portion was arranged so that the outer peripheral portion of the movable iron core did not overlap in the radial direction. Thus, the initial suction force can be reliably increased.

[0015]

Next, a magnet switch according to the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
Excitation coil 3 of magnet switch 1 according to the embodiment
FIG. 4 shows a cross-sectional view when power is not supplied.

The magnet switch 1 uses an electromagnetic driving means to press the movable contact 5a into and out of contact with the pair of fixed contact portions 6, 6, thereby electrically connecting the fixed contact portions 6, 6 to each other. It conducts and shuts off. The electromagnetic driving means mainly includes a movable iron core 2, an exciting coil 3 arranged on the outer periphery of the movable iron core 2, and a fixed iron core 4 arranged to face the movable iron core 2 and to attract the movable iron core 2 when the exciting coil is energized. The movable core 2 holds the movable contact 5a integrally with the movable core 2 so as to be able to advance and retreat in the axial direction.

Hereinafter, the configuration of the magnet switch 1 will be described.

The bobbin 18 is made of an insulating material (for example, an insulating resin or the like), is formed into a shape in which flanges are provided at both ends of a cylinder, and the exciting coil 3 is wound therearound. As shown in FIG. 1, an annular magnetic body 19 is insert-molded on the inner peripheral portion of the bobbin 18. The magnetic body 19 is formed of a magnetic material (for example, silicon steel or the like). The axial position of the magnetic body 19 is set so as not to overlap the outer peripheral surface of the movable iron core 2 in the radial direction when the exciting coil 3 is not energized, that is, in the state shown in FIG. That is, the gap C1 is formed between the axial end face of the magnetic body 19 (the right end in FIG. 1) and the axial end face of the movable core 2 (the left end in FIG. 1).

The yoke 21 is formed in a substantially cylindrical shape with a bottom, and accommodates the bobbin 18 coaxially.

The sleeve 20 for suppressing contact and sliding between the magnetic body 19 and the movable core 2 (described later) is made of a non-magnetic material (for example, brass or resin) in a cylindrical shape.
It is press-fitted and fixed to the inner periphery of the bobbin 18 and the yoke 21. The outer peripheral surface of the sleeve 20 is in contact with the magnetic body 19. The role of the sleeve 20 is to prevent contact between the magnetic body 19 and the movable core 2, while it is desirable that the magnetic body 19 and the movable core 2 are close to each other in the radial direction in terms of the magnetic circuit configuration. Therefore, it is desirable that the thickness of the sleeve 20 be as thin as possible within a range where the assembling operation is possible. Further, since the movable core 2 slides on the inner peripheral surface of the sleeve 20, the sleeve 20 is selected from materials having good compatibility with the movable core 2 (low friction coefficient, high wear resistance, etc.). You.

The fixed iron core 4 has a substantially disc shape, and the bobbin 1
8 is fixed coaxially to the end of the yoke 21 opposite to the bottom and is in press contact with the yoke 21. Fixed iron core 4
Is fixed to the bobbin 18 and the magnetic body 19
As shown in FIG. 1, is disposed apart from the fixed iron core 4 in the axial direction. That is, the gap C2 is formed between the axial end face of the magnetic body 19 (the left end in FIG. 1) and the axial end face of the fixed core 4 (the right end in FIG. 1).

As shown in FIG. 1, the movable core 2 is slidably fitted on the inner peripheral side of the sleeve 20. Movable iron core 2
A small-diameter portion 2a is coaxially provided at an end opposite to the fixed iron core 4 to form a locking portion 2b for locking a movable portion 5 (described later). The movable portion 5 is slidably fitted to the small diameter portion 2a. A stopper 2c is fixed to the end face of the movable iron core 2 opposite to the fixed iron core 4 by welding. A spring 10 is provided between the movable part 5 and the stopper 2c.
Is provided, and the movable portion 5 is urged in the direction of the fixed contact 6b (described later) (that is, the direction in which the movable portion 5 is locked by the locking portion 2b) to bring the movable portion 5 into contact with the locking portion 2b. In addition, movable iron core 2
Is biased away from the fixed core 4 by the biasing force of the spring 9, and when the excitation coil 3 is not energized, the distance between the movable core 2 and the fixed core 4, that is, the air gap is maximized. .

Here, when the exciting coil 3 is energized, a magnetic circuit is formed by the movable iron core 2, the fixed iron core 4, and the yoke 21.

The movable section 5 comprises a movable contact 5a made of a conductive metal material, a holder 5b made of an insulating material, and a plate 5c. These three members are integrally slidably fitted to the small diameter portion 2a of the movable iron core 2 by a spring 10. The movable contact 5a is electrically insulated from the movable core 2 by the holder 5b and the plate 5c.
In addition, the movable contact 5a includes a pair of fixed contact portions 6, which will be described later,
6, the magnet switch 1 is closed.

The pair of fixed contact portions 6, 6 are made of a conductive metal material, and have a base portion 6a via a bolt 12, an insulating sleeve 13, an O-ring 14, an O-ring 15, and an insulating member 16 and a housing 8. Electrically insulated from
The housing 8 is fixed to the circumference of the housing 8 so as to face each other. The fixed contact 6b is set in a radial direction in a plane orthogonal to the axis of the housing 8. When the fixed contact 6b and the movable contact 5a come into contact, the pair of fixed contact portions 6, 6 are electrically connected.

The housing 8 accommodates the movable core 2 and the exciting coil 3 and the like, and holds the fixed contact portion 6. A cover 11 is fixed to the housing 8. When the excitation coil 3 is not energized, the movable iron core 2 moves away from the fixed iron core 4 by the urging force of the spring 9, and the holder 5 b of the movable part 5 held by the movable iron core 2 is in contact with the cover 11. .

The insulator 7 is made of a ring-shaped insulating material, is sandwiched and fixed between the exciting coil 3 and the fixed contact 6b in the housing 8, and electrically insulates the exciting coil 3 from the fixed contact 6b. I have.

Next, the operation of the magnet switch 1 will be described.

(1) When the excitation coil 3 is not energized.

At this time, the movable core 2 is urged rightward in FIG. 1 by the urging force of the spring 9, and the movable portion 5a is separated from the movable contact 5a and the pair of fixed contacts 6b, 6b.
Is in contact with the cover 17. Accordingly, conduction between the pair of fixed contact portions 6, 6 is cut off, and the magnet switch 1 is in an open state. At this time, the movable portion 5 is in contact with the locking portion 2b.

(2) When the excitation coil 3 is energized.

When the excitation coil 3 is energized, the excitation coil 3
Generates a magnetic force, and the movable iron core 2 is attracted by the fixed iron core 4 and moves to the left in FIG.

With the movement of the movable core 2, the movable part 5 also moves integrally with the movable core 2. When the movable contact 5a comes into contact with the fixed contact 6b and stops, the movable contact 5a electrically connects the pair of fixed contact portions 6, 6, and the magnet switch 1 is closed. At this time, the movable iron core 2
Has not yet contacted the fixed core 4 and moves until only the movable core 2 contacts the fixed core 4. By this movement, the spring 10 is compressed, and the repulsive force is transmitted to the movable contact 5a via the holder 5b, and the movable contact 5a
Is pressed against the pair of fixed contact portions 6. That is,
The repulsive force of the spring 10 becomes a contact pressing load. Due to this pressing load, occurrence of arc discharge and contact damage are suppressed.

(3) When the energization of the exciting coil 3 is stopped.

When the energization of the exciting coil 3 is stopped, the magnetic force of the exciting coil 3 disappears and the attraction force disappears.
Move in the direction (right side in FIG. 1) away from the
Holder 5b comes into contact with the cover 11 and stops. At this time, the movable contact 5a is separated from the fixed contact 6b, the electrical conduction between the pair of fixed contacts 6 is cut off, and the magnet switch 1 is again opened.

Next, when the exciting coil 3 is energized, the movable core 2
Will be described focusing on the effect exerted by the magnetic body 19.

FIG. 2 is a graph showing the relationship between the suction force acting on the movable core 2 and the air gap (the distance between the movable core 2 and the fixed core 4). The vertical axis indicates the suction force, and the horizontal axis indicates the air gap. Air gap = A indicates when the exciting coil 3 is not energized, while air gap = 0 indicates that the movable iron core 2 is fixed when the exciting coil 3 is energized. 4 shows the state of contact.

In FIG. 2, a characteristic X indicates an attractive force characteristic of the magnet switch 1 according to the first embodiment of the present invention. A characteristic Y indicates an attractive force characteristic of a conventional magnet switch (with a magnetic material, actual opening 61-15311). Characteristic Z
Shows the attraction force characteristics of a conventional magnet switch (without a magnetic body). Further, the characteristic S acts on the movable iron core 2,
The sum of the urging force of the spring 9 and the urging force of the spring 10 is shown.

Hereinafter, the movement of the movable core 2 until it comes into contact with the fixed core 4 will be described in several stages.

First, when the exciting coil 3 is energized, a magnetic circuit is formed by the movable iron core 2, the fixed iron core 4, and the yoke 21. Here, the magnetic body 19 plays a role of an auxiliary magnetic circuit, and reduces the magnetic resistance between the movable core 2 and the fixed core 4. Therefore, the attractive force generated immediately after the excitation coil 3 is energized, that is, the initial attractive force increases as compared with the case where the magnetic body 19 is not provided. The movable iron core 2 is reliably moved to the fixed iron core 4 side (the left side in FIG. 1 and the left side in FIG. 2) by this suction force. Then, as the movable iron core 2 moves, that is, as the air gap decreases, the suction force increases.

When the movable core 2 eventually overlaps the magnetic body 19, a magnetic flux leaking from the movable core 2 to the magnetic body 19 is generated. Since the direction of the leakage magnetic flux is different from the direction of the attractive force, the attractive force is reduced. Therefore, the moving speed of the movable iron core 2 decreases. For this reason, the speed at which the movable core 2 contacts the fixed core 4 is also reduced, so that the bounce of the movable core 2 at the time of contact with the fixed core 4 can be suppressed.

Further, after the movable core 2 moves and the tip of the movable core 2 (the left end in FIG. 1) passes through the magnetic body 19, the magnetic flux leaking from the movable core 2 to the magnetic body 19 gradually decreases. Therefore, the suction force increases again, and when the air gap is 0, the suction force is restored to the same level as when the magnetic body 19 is not provided, so that a sufficient contact load can be obtained.

On the other hand, in the conventional magnet switch (with a magnetic material, see Japanese Utility Model Application Laid-Open No. 153331/1986), the magnetic material is in contact with the fixed iron core 4, so that the movable iron core 2 is kept in contact with the fixed iron core 4. Leakage magnetic flux is generated from the movable core 2 to the magnetic body 19. Therefore, as shown by the characteristic B in FIG. 2, a sufficient contact load cannot be obtained when the air gap = 0.

As described above, in the magnet switch 1 according to the first embodiment of the present invention, the sleeve 20 is slidably disposed on the outer periphery of the movable core 2 so that the magnetic body 19 and the movable core 2 are connected to each other. It does not slide directly. Accordingly, it is possible to prevent problems such as a decrease in slidability of the movable iron core 2 due to wear of the magnetic body 19 and an operation failure due to formation of a new magnetic circuit due to abrasion powder of the magnetic body 19.

Further, the magnetic body 19 is disposed so as to be axially separated from the fixed iron core 4 and not to overlap the outer peripheral surface of the movable iron core 2 in the radial direction when the exciting coil 3 is not energized. That is, in FIG. 1, they are arranged so that the gaps C1 and C2 are formed. As a result, the suction force at the air gap = 0 is increased while the initial suction force is increased.
Can be restored to the same level as in the case where there is no contact, and a sufficient contact load can be secured.

Further, as described in the description of the operation, by providing the magnetic body 19, the moving speed of the movable core 2 can be temporarily suppressed, so that when the movable core 2 contacts the fixed core 4, Bounce can be prevented.

In the above-described magnet switch 1 according to the first embodiment of the present invention, the sizes of the gaps C1 and C2 or the magnetic characteristics of the magnetic body 19 shown in FIG. The initial suction force, the contact load, and the bounce characteristics of the movable core 2 can be optimized as needed.

In the magnet switch 1 according to the first embodiment of the present invention, the magnetic body 19 is
Although insert molding was used, it may be provided by other methods. For example, an annular groove is provided on the inner peripheral surface of the bobbin 18,
The magnetic body 19 may be fitted in this groove. In this case, as shown in FIG. 3A, for example, the magnetic body 19 has a substantially C-shaped cross-section in the circumferential direction.
As shown in (b), it is only necessary to elastically deform and mount the bobbin 18.

In the first embodiment, the magnetic material 1
9 is arranged such that its inner peripheral surface is flush with the inner peripheral surface of the bobbin 18, and is arranged such that the outer peripheral surface of the magnetic body 19 is flush with the outer peripheral surface of the bobbin 18. May be. Alternatively, as shown in FIG. 5, the magnetic body 19 may be embedded in the bobbin 18. In these cases, the sleeve 20 may be eliminated, and the movable iron core 2 may be configured to slide directly on the inner peripheral portion of the bobbin 18.

In the magnet switch 1 according to the first embodiment of the present invention, the movable portion 5 holding the movable contact 5a is locked to the movable core 2 even when the excitation coil 3 is not energized. A configuration in which these are separated may be used. That is, when the excitation coil 3 is not energized, the movable part 5 holding the movable contact 5 a and the movable core 2 are separated, but when the excitation coil 3 is energized, the movable core 2 is attracted to the fixed core 4. The movable portion 5 that holds the movable contact 5a and the movable iron core 2 may be integrally moved thereafter.

(Second Embodiment) FIG. 6 shows a second embodiment of the present invention.
1 shows a partial cross-sectional view of a magnet switch 1 according to the embodiment. In the second embodiment, the magnetic body 19 is changed from the first embodiment, and a linear magnetic body 22 is employed.

The magnetic body 22 is wound coaxially with the exciting coil 3 over substantially the entire length of the bobbin 18.
Insert molded inside. The linear magnetic body 22 is
As shown in FIG. 6, the magnetic material 19 in the first embodiment
Are wound in close contact with each other, and are wound with an interval before and after in the axial direction.

In the second embodiment, the same effect as in the first embodiment can be obtained by the closely wound portion of the magnetic body 22.

Further, the magnetic material 22 formed by insert molding
Accordingly, even if the exciting coil 3 generates heat, the bobbin 18 can be prevented from being deformed by heat.

Also, by appropriately selecting the axial position and length of the closely wound portion of the magnetic body 22, the initial suction force and the contact point can be adjusted in the second embodiment as in the first embodiment. The load and the bounce characteristics of the movable core 2 can be optimized as required.

In the second embodiment, the sleeve 20 may be omitted, and the movable iron core 2 may slide directly on the inner peripheral portion of the bobbin 18.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a magnet switch 1 according to a first embodiment of the present invention when an exciting coil 3 is not energized.

FIG. 2 is a graph showing a relationship between an attractive force acting on a movable core 2 of a magnet switch 1 and an air gap according to the first embodiment of the present invention.

FIG. 3A is a cross-sectional view of the magnet switch 1 according to the first embodiment of the present invention in a modified state in which a magnetic body 19 is mounted. FIG. 3B is a cross-sectional view of the magnet switch 1 according to the first embodiment during the mounting operation of the magnetic body 19.

FIG. 4 is a partial sectional view showing a first modification of the bobbin 18 of the magnet switch 1 according to the first embodiment of the present invention.

FIG. 5 is a partial sectional view showing a second modification of the bobbin 18 of the magnet switch 1 according to the first embodiment of the present invention.

FIG. 6 is a partial sectional view of a magnet switch 1 according to a second embodiment of the present invention.

[Description of Signs] 1 Magnet switch 2 Movable core 2a Small diameter portion 2b Locking portion 2c Stopper 3 Exciting coil 4 Fixed core 5 Movable portion 5a Movable contact 5b Holder 5c Plate 6 Fixed contact 6a Base 6b Fixed contact 7 Insulator 8 Housing 9 Spring 10 Spring 11 Cover 12 Terminal bolt 13 Insulation sleeve 14 O-ring 15 O-ring 16 Insulation member 17 Nut 18 Bobbin 19 Magnetic body 20 Sleeve 21 Yoke 22 Magnetic body A Air gap C1 Gap C2 Gap S characteristics (biasing force) X characteristics (suction force) Y characteristics (suction force) Z characteristics (suction force)

Claims (6)

[Claims] 1. A movable core, an exciting coil wound around a bobbin and loosely fitted around the outer periphery of the movable core, and fixed to be disposed to face the movable core and to attract the movable core when the exciting coil is energized. An iron core; a movable contact arranged so as to be able to advance and retreat in the axial direction integrally with the movable iron core; a pair of fixed contacts arranged to face the movable contact and coming into contact with the movable contact by moving the movable iron core; In a magnet switch having a magnetic body disposed on an inner peripheral side of an exciting coil and an outer peripheral side of the movable core, a cylindrical sleeve made of a non-magnetic substance is slidably disposed on an outer periphery of the movable core. A magnet switch, wherein the magnetic body is disposed between the outer periphery of the sleeve and the inner periphery of the exciting coil so as to be axially separated from the fixed iron core. 2. The magnetic body is arranged so that the magnetic body and the outer peripheral portion of the movable iron core do not overlap in the radial direction when the excitation coil is not energized.
Magnet switch described in. 3. The magnet switch according to claim 1, wherein a groove coaxial with the bobbin is provided on an outer periphery or an inner periphery of the bobbin, and the magnetic body is mounted in the groove. 4. The magnet switch according to claim 1, wherein the magnetic body is insert-molded on the bobbin. 5. A movable iron core, an exciting coil wound around a bobbin and loosely fitted around the outer periphery of the movable iron core, and fixed to be disposed to face the movable iron core and to attract the movable iron core when the exciting coil is energized. An iron core; a movable contact arranged so as to be able to advance and retreat in the axial direction integrally with the movable iron core; a pair of fixed contacts arranged to face the movable contact and coming into contact with the movable contact by moving the movable iron core; In a magnet switch having a magnetic body disposed on an inner peripheral side of an exciting coil and an outer peripheral side of the movable core, a cylindrical sleeve made of a non-magnetic substance is slidably disposed on an outer periphery of the movable core. A magnetic switch, wherein the magnetic body is linear and insert-molded in a state of being wound coaxially with the exciting coil over substantially the entire length of the bobbin. 6. The winding state of the magnetic body includes a loosely wound portion and a closely wound portion, and when the exciting coil is not energized, the tightly wound portion and the outer peripheral portion of the movable iron core have a radius. The magnet switch according to claim 5, wherein the close-wound portion is arranged so as not to overlap in a direction.