JPH0482639A - Magnetic fixing device - Google Patents

Abstract

PURPOSE:To maintain a magnetic void stably for a long term, by binding two members which form a magnetic void with plural screws via the nonmagnetic material arranged in the magnetic void. CONSTITUTION:A housing 20, 1st yoke 22 and an iron core 24 are integrally composed of a strong magnetic material, a 2nd yoke 28 is arranged in a magnetic void 30 from the iron core 24 and at interval from the inner face of the housing 20, and a nonmagnetic material 32 is filled up in the magnetic void 30. To the iron core 24 plural screws 34 which penetrate through the 2nd yoke 28 and which are composed of nonmagnetic materials are screwed, and plural screws 36 which abut on the iron core 24 and composed of nonmagnetic materials are screwed to the 2nd yoke 28. The relative positional relation of the housing 20, 1st yoke 22, iron core 24, 2nd yoke 8 and permanent magnet 14 is maintained by the nonmagnetic material 32 filled up in the internal space of the housing 20, and the magnetic void 30 is maintained by the common action of the nonmagnetic material 32 and screws 34, 36.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic fixing device that uses a permanent magnet and an excitation coil to attract and release a magnetic material.

(Prior art) As a magnetic fixing device that uses a permanent magnet and an excitation coil, when a magnetic body is attracted, the magnetic flux of the permanent magnet puts the attraction part in an excited state, and when the magnetic body is released, the permanent magnet is turned on. There is a device that keeps the attracting part in a non-excited state by preventing magnetic flux from appearing in the attracting part using the magnetic flux of an excitation coil.

In this known magnetic fixing device, the magnetic flux from the permanent magnet is prevented from passing through the magnetic gap, which acts as a leakage path, due to the magnetic field generated by the excitation coil, while the attraction part is in the de-energized state. It is allowed, but is prevented from passing through the suction part.

In this type of magnetic fixing device, when the size of the magnetic gap changes, the magnetic resistance value of the magnetic gap changes, and the amount of magnetic flux passing through the magnetic gap changes, so the attracting part is completely de-energized. All I can do is leave it behind.

In order to prevent this, the magnetic gap is filled with a non-magnetic material such as resin or solder, and the member forming the magnetic gap is adhered to the non-magnetic material.

(Problem to be solved) However, in conventional magnetic fixing devices of this type, after long-term use, the non-magnetic member separates from the member forming the magnetic gap, and as a result, the size of the magnetic gap changes. Put it away.

An object of the present invention is to provide a magnetic fixing device that can stably maintain a magnetic gap for a long period of time.

(Solution, Operation, Effect) The magnetic fixing device of the present invention includes an electromagnet assembly that selectively switches an attraction part that attracts a magnetic body between an energized state and a de-energized state, and a permanent magnet arranged in the electromagnet assembly. including.

The electromagnet assembly includes a cylindrical housing, a first yoke disposed at one end of the housing and magnetically connected to the housing, an iron core disposed within the housing, and a first yoke arranged around the iron core. and a second yoke disposed within the housing.

the second yoke and the iron core, the first yoke and the iron core, the first yoke and the second yoke, or
The housing and the second yoke together form a magnetic gap that acts as a leakage path for the magnetic flux from the permanent magnet while the attraction part is in a non-excited state.

A non-magnetic material is disposed in the magnetic gap, and the two members forming the magnetic gap include a plurality of screws that pass through one of the two members and the non-magnetic material and are screwed to the other of the two members. or by a plurality of screws screwed into one of the two members and abutted on the other of the two members via the non-magnetic material.

According to the magnetic fixing device of the present invention, two members forming a magnetic gap are arranged in the magnetic gap by a plurality of screws that pass through one of the members and the non-magnetic member and are screwed into the other member. Since they are coupled via a non-magnetic material, changes in the magnetic gap are prevented by the joint action of the wire and the non-magnetic material, thus making it possible to maintain the magnetic gap stably for a long period of time.

Furthermore, when assembling the magnetic fixing device, the size of the magnetic gap can be adjusted and maintained in that state using the plurality of screws, so the size of the magnetic gap can be adjusted accurately and easily. .

Another magnetic fixing device of the present invention includes a face plate that defines an attraction part that attracts a magnetic body, an electromagnet assembly that selectively switches the attraction part between an energized state and a de-energized state, and the electromagnet assembly and the face plate. and a permanent magnet disposed on one side of the magnet. The electromagnet assembly is constructed similarly to the magnetic fixing device described above.

(Example) Referring to FIGS. 1 and 2, a magnetic fixing device 10 includes an electromagnet assembly 12, a plurality of permanent magnets 14 disposed in the electromagnet assembly, and a face plate 16. The attraction surface 18 of the face plate 16 is connected to the electromagnet assembly 12 and the permanent stone 14.
When the attraction surface 18 is placed in an excited state due to the joint action of
It is attracted to the magnet and released from the attraction surface 18'' when placed in a de-energized state.

The electromagnet assembly 12 is arranged in a space formed by a square cylindrical housing sink 20, a first yoke 22 arranged to close one end of the housing, and the housing 20 and the first yoke 22. The housing 20 includes an iron core 24 made of a ferromagnetic material, an excitation coil 26 surrounding the iron core, and a second yoke 28 disposed at the other end of the housing 20.

The housing 20, the first yoke 22, and the iron core 24 are
It is made in one piece from ferromagnetic material.

The second yoke 28 is spaced apart from the core 24 by a magnetic gap 30 and from the inner surface of the housing 20 . The magnetic chamber [30 is filled with a non-magnetic material 32 such as solder or synthetic resin.

A plurality of screws 34 made of a non-magnetic material are screwed into the iron core 24 and pass through the second yoke 28 . A plurality of screws 36 are screwed together.

The permanent magnet 14 is made of a high coercivity permanent magnet material such as a ferrite magnet, preferably a polarity irreversible permanent magnet material, and is disposed between the housing 2o and the second yoke 28. The permanent magnet 14 is magnetized in a direction perpendicular to the axis of the housing 20.

For illustrative purposes, the permanent magnet 14 is attached to the housing 2 as shown.
It is assumed that the 0 side is magnetized to S and the second yoke 28 side is magnetized to N, but they may be magnetized in the opposite direction. The magnetic pole surface of the permanent magnet 14 is in contact with the housing 20 and the second yoke 28 .

The relative positional relationship of the housing 20, the first yoke 22, the iron core 24, the second yoke 28, and the permanent magnet 14 is maintained by a nonmagnetic material 32 filled in the internal space of the housing 2o.

The magnetic chamber [30 is also maintained by the cooperation of the non-magnetic material 32 filled therein and the screws 34,36.

The face plate 16 is arranged between a plurality of elongated first and second pole pieces 38.40 arranged alternately and in parallel with each other and between adjacent first and second pole pieces 38.40. It is also provided with a spacer 42 made of a non-magnetic material, and is attached to the housing 20 with a plurality of bolts (not shown).

Each first pole piece 38 is magnetically connected to the housing 20 or magnetically isolated from the second yoke 28 at both longitudinal ends thereof. On the other hand, each second pole piece 40 has a second yoke 2 at its center.
8, but magnetically isolated from the housing 20.

Each first pole piece 38 actually abuts a pair of opposing walls of the housing 20 .

Therefore, the other pair of opposing walls of the housing 20 may be made of non-magnetic material.

The attraction surface 18 that attracts the magnetic material is defined by the first and second magnetic pole pieces 38, 40 and the spacer 42.

When no excitation current is supplied to the excitation coil 26, the magnetic flux of the permanent magnet 14 is determined by the dotted lines 44a, 44b, 4 in FIG.
Pass in the direction of the arrow 4c. The magnetic flux 44a is the total magnetic flux of the permanent magnet 14 in the illustrated state. Magnetic flux 44a, 4
The magnetic flux amount of 4b and 44c is A4
4a, A44b and A44c, A44a=A
The relationship is 44b+A44c.

The magnetic flux 44a of the permanent magnet 14 enters the second yoke 28 from the N pole of the permanent magnet 14, and becomes a magnetic flux 44b.

44c. The magnetic flux 44b is transmitted through the second yoke 28,
Face plate 16, suction surface 18, face plate 16 and housing 20
The magnetic flux passes through the housing 20, merges with the magnetic flux 44c, and returns to the S rod of the permanent magnet 14.

The magnetic flux 44c is a leakage magnetic flux passing through the second yoke 28, the magnetic gap 30, the iron core 24, the first yoke 22, and the housing 20, and does not affect the attraction of the magnetic material. Therefore, the attraction surface 18 is placed in a weakly excited state by the magnetic flux 44b.

When the attraction surface 18 is placed in an excited state, a first exciting current is supplied to the exciting coil 26 . As a result, magnetic fluxes 46a, 46b, and 46c are generated by the exciting coil 26 in the direction of the arrow shown by the dashed line in FIG. The amount of magnetic flux of magnetic fluxes 46a, 46b and 46c is equal to the amount of magnetic flux B46 a
.

Assuming B46b and B46c, B46c=B46a+B46b There is a relationship between

The magnetic flux passing through the magnetic air gap 30 is a composite magnetic flux of the magnetic flux 44c caused by the permanent magnet 14 and the magnetic flux 46c caused by the excitation coil 26. However, since the magnetic fluxes 44c and 46c are set to have the same amount of magnetic flux in opposite directions and in absolute values, the magnetic fluxes 44c and 46c are prevented from passing through the magnetic air gap 30.

On the other hand, the magnetic flux passing through the attraction surface 18 is the magnetic flux 44b caused by the permanent magnet 14 and the exciting coil 26.

46b. Since the directions of the magnetic fluxes 44b and 46b are the same, only the magnetic flux corresponding to the sum of the magnetic fluxes 44b and 46b passes through the attraction surface 18. Therefore, the attraction surface 18 is placed in a strongly excited state, and the magnetic material is reliably attracted to the attraction surface 18.

When the attraction surface 18 is placed in a non-excited state, a second excitation current having a polarity opposite to that of the first excitation current is supplied to the excitation coil 26 . As a result, the magnetic fluxes 48a and 4 shown by the two-dot chain line in FIG.
8b and 48c are generated by the exciting coil 26. Magnetic flux 48a.

The directions of 48b and 48c, as indicated by the arrows, respectively correspond to the magnetic flux 46a indicated by the dashed line in FIG.

46b and 46c are the opposite. Magnetic flux 48a.

The amount of magnetic flux of 48b and 48c is C48a, respectively.

Given C48b and C48c - bundle 48a.

48b and 48c are C48c=C48a+C48b There is a relationship between

The magnetic flux passing through the second yoke 28, the face plate 16, the attraction surface 18, the face plate 16, and the housing 20 is composed of a magnetic flux 44b due to the permanent magnet 14 and a magnetic flux 48b due to the excitation coil 26.
The magnetic fluxes 44b and 48b are set to have different directions and the same amount of magnetic flux in absolute value. Therefore, the attraction surface 18 is placed in a non-excited state, and the magnetic material is reliably released from the attraction surface 18.

The magnetic flux of the permanent magnet 14 is prevented from passing through the magnetic gap 30 when the attraction surface 18 is placed in an excited state, and the magnetic flux of the permanent magnet 14 is prevented from passing through the magnetic gap 30.
When the magnet is placed in a de-energized state, it is prevented from passing through the attraction surface 18.

Therefore, according to the magnetic fixing device 10, compared to conventional magnetic fixing devices, it is possible to eliminate leakage magnetic flux passing through the magnetic gap 30 when the attraction surface 18 is placed in an excited state, and the magnetic resistance of the magnetic gap 30 can be eliminated. Since it is possible to reduce the amount of permanent magnets 14 incorporated into the device and the magnetomotive force generated by the excitation coil 26, it is possible to reduce the excitation current of the excitation coil 26.

In the magnetic fixing device 10, when the second yoke 28 is displaced with respect to the iron core 24 by the screws 34 and 36 before filling the space inside the housing 20 with the non-magnetic material 32, the size of the magnetic gap 30 changes. do. When the size of the magnetic gap 30 changes, the magnetic resistance value of the magnetic gap 30 changes, and as a result, the amount of magnetic flux appearing on the attracting surface 18 and the amount of magnetic flux passing through the magnetic gap 30 changes.

For this reason, during assembly, the size of the magnetic gap 30 is adjusted such that leakage magnetic flux does not occur between the housing 20 and the second yoke 28, for example, when the second excitation current is supplied to the excitation coil 26. is adjusted by screws 34 and 36, and then the space in the housing 20 is filled with a non-magnetic material 32,
Next, the top surface of the electromagnet assembly 12 is polished, and the rear face plate 16 is polished.
can be attached to the top surface of the electromagnet assembly 12.

In this way, the size of the magnetic gap can be reduced to 34.3
6 and maintain that state, the size of the magnetic gap 30 can be adjusted accurately and easily.

In the magnetic fixing device shown in FIGS. 1 and 2, the second
The first yoke 28 is disposed in the housing 20 so as not to be relatively displaceable, and the first yoke 22 and the iron core 24 are attached to the housing 20.
It may be disposed so as to be displaceable in the axial direction.

In this case, the first yoke 22 is separated from the housing 20 at a portion corresponding to the inner surface of the house sink 20, and is magnetically connected to the housing 20. Neshi 34
passes through the first yoke 22 and the iron core 24 and is screwed into the second yoke 28. The neck 36 is the first yoke 2
2 and the iron core 24, and is brought into contact with the lower surface of the second yoke 28.

Like the magnetic fixing device 50 shown in FIG. 3, the iron core 24 is separated from the first yoke 22, and the iron core 24 and the second yoke 2
8 may be integrated. The magnetic gap 30 is formed by the first yoke 22 and the iron core 24. The screw 34 is
It passes through the second yoke 28 and the iron core 24 and is screwed into the first yoke 22. The neck 36 is the second yoke 2
8 and the iron core 24, and is in contact with the first yoke 22.

In the magnetic fixing device 50, the magnetic flux of the permanent magnet 14, the magnetic flux generated by the excitation coil 26 when the first excitation current is supplied to the excitation coil 26, and the second excitation! The magnetic flux generated by the excitation coil 26 when supplied with the ff current is indicated by the same reference numerals as in the embodiment shown in FIG.

Therefore, when the first excitation current is supplied to the excitation coil 26, the attraction surface 18 allows the magnetic fluxes 44b and 4 to pass through the attraction surface 18.
6b are in the same orientation and the magnetic flux 44 passing through the magnetic air gap 30
Since c and 46c are in opposite directions, the magnet is placed in an excited state. Further, the attraction surface 18 receives a magnetic flux 44b that passes through the attraction surface 18 when the second excitation current is supplied to the excitation coil 26.

48b or in the opposite direction, and the magnetic flux 44 passing through the magnetic gap 3o
c and 48c are in the same direction, so they are placed in a de-energized state.

In the case of the magnetic fixing device 50 as well, the iron core 24 and the second yoke 28 may be disposed relative to the housing 20 so as not to be displaceable, and the first yoke 22 may be disposed relative to the housing 20 so as to be displaceable in the axial direction thereof. . In this case, the first yoke 2
2 is separated from the housing 20 at a portion corresponding to the inner surface of the housing 20 and is magnetically connected to the housing 2°. The screw 34 passes through the second yoke 28 and the iron core 24 and is screwed into the first yoke 22.

The screw 36 is screwed into the second yoke 28 and the iron core 24, and is brought into contact with the upper surface of the first yoke 22.

As shown in FIG. 4, the iron core 24 is
Also, the second yoke 28 may be arranged upside down. Further, the magnetic fixing device 52 also arranges the iron core 24 and the second yoke 28 in the housing 20 so as not to be relatively displaceable, and the first
The yoke 22 may be arranged to be movable in the axial direction of the housing 20.

In the magnetic fixing device 54 shown in FIG. 5, the iron core 24 and the second yoke 28 are integrated, and the integrated member is divided into two members 56a and 56b in the width direction of the housing 20. A non-magnetic elastic member 58 such as rubber is arranged between the members 56a and 56b. magnetic air gap 3
0 is formed between the housing 20 and each member 56a, 56b.

In the magnetic fixing device 54, each permanent magnet 14 is mounted between the first yoke 22 and the member 56a or 56b together with the corresponding member in the housing 20 and the first yoke 22.
It is arranged so that it can be displaced with respect to. Further, the sizes of the iron core 24 and the excitation coil 26 are selected such that the iron core 24 or the excitation coil 26 can be displaced inside the iron core 24 or the excitation coil 26. Neshi 34
passes through housing 20 and includes member 56a or 56b.
are screwed together. The screw 36 is screwed into the housing 20 and abuts against the member 56a or 56b.

Each permanent magnet 14 may be arranged on the face plate 16, like the magnetic fixing device 60 shown in FIG.

In the magnetic fixing device 60 shown in FIG.
4 is located between the first and second &B pole pieces 38° 40 and below the spacer 42. Each permanent magnet 1
One of the Mi magnetic pole faces of 4, for example S, is in contact with the first magnetic pole piece 38, and the other magnetic pole face is in contact with the second magnetic pole piece 40.

A magnetic gap 30 is formed between the first yoke 22 and the iron core 24. Therefore, in the magnetic fixing device 60, the magnetic flux when the excitation WL current is not supplied to the excitation coil 26, when the first excitation current is supplied, and when the second excitation current is supplied is as shown in FIGS. It is the same as the magnetic fixing devices 10 and 50 shown in the figure.

The magnetic fixing device 70 shown in FIGS. 7 and 8 includes a plurality of electromagnet assemblies 72, a plurality of permanent magnets 74 disposed in each electromagnet assembly, and one magnet commonly used in the electromagnet assemblies 72. It includes a face plate 76 and a flat base 78 that interconnects the electromagnet assemblies 72. The magnetic material is attracted to the attracting surface 80 of the face plate 76 when the attracting surface 80 is in an energized state due to the joint action of the electromagnet assembly 72 and the permanent magnet 74, and is attracted to the attracting surface 80 when it is in a non-energized state. To be released.

Each electromagnet assembly 72 is, in the illustrated example, the same as the electromagnet assembly 12 of the magnetic fixture @10 shown in FIGS. 1 and 2, but may be an electromagnet assembly of another magnetic fixture. good.

The face plate 76, like the face plate 16, includes a plurality of elongated first and second magnetic pole pieces 8 arranged alternately and parallel to each other.
2.84 and adjacent first and second pole pieces 82.8
4, and is attached to the housing 20 of each electromagnet assembly 72 by a plurality of bolts (not shown).

Each first pole piece 82 is magnetically connected to the housing 20 of each electromagnet assembly 72 at its ends, or is magnetically isolated from the second yoke 28 . In contrast, each second pole piece 84 is either magnetically connected to the second yoke 28 of each electromagnet assembly 72 at its center or magnetically isolated from the housing 20.

In the magnetic fixing device 70, the number of electromagnet assemblies 72 used is determined according to the size of the face plate 76.

In the magnetic fixing device 70, when no excitation current is supplied to the excitation coil 26 of each electromagnet assembly 72, the attraction surface 80 is placed in a weakly excited state by the permanent magnet 74. In contrast, the excitation coil 26 of each electromagnet assembly 72 has a first
When the excitation Wt current is supplied, the attraction surface 80 is brought into an excited state.

Further, when the second excitation current is supplied to the excitation coil 26 of each electromagnet assembly 72, the attraction surface 80 is placed in a non-excited state.

According to the magnetic fixing device 70, since the magnetic gap of each electromagnet assembly 72 is adjustable, the electromagnet assembly 72 can be standardized, and maintenance and management of the electromagnet assembly 72 is facilitated. It is possible to manufacture a large number of electromagnet assemblies 72 in advance.

The present invention can also be applied to a magnetic fixing device that supplies an excitation current to an excitation coil only when the attraction surface is placed in a non-excited state. In this case, the magnetic gap is preferably of a size such that when the attracting surface is placed in an excited state, most of the magnetic flux of the permanent magnet passes through the attracting surface without passing through the magnetic gap.

Furthermore, the present invention can also be applied to a magnetic fixing device that does not use a face plate. In this case, the attraction surface is defined by the housing and the iron core or the housing and the second yoke. If screws 34 and 36 are used, it is possible to easily adjust the magnetic gap when assembling the magnetic fixing device, and only one screw can be used.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the magnetic fixing device of the present invention, FIG. 2 is an enlarged sectional view taken along line 2-2 in FIG. 1,
3, 4 and 5 are enlarged sectional views similar to FIG. 2 showing other embodiments of the magnetic fixing device, and FIG. 6 shows still another embodiment of the magnetic fixing device. 1, FIG. 7 is a diagram showing still another embodiment of the magnetic fixing device, and FIG. 8 is a sectional view taken along line 8--8 in FIG. 7. 10.50, 52, 54, 60.70: Magnetic fixing device, 12.72 Electromagnet assembly, 14.74: Permanent magnet, 16.76: Face plate, 18.80
: suction surface, 20: housing, 22: first yoke,
24: Iron core, 26° excitation coil, 28: Second
Yoke, 30: Magnetic gap, 32: Non-magnetic material, 34. 36: Neck for magnetic gap adjustment.

Claims (2)

[Claims] (1) An electromagnet assembly that selectively switches an attraction part that attracts a magnetic material between an energized state and a non-excited state, and a permanent magnet disposed in the electromagnet assembly, and the electromagnet assembly has a cylindrical shape. a first yoke disposed at one end of the housing and magnetically connected to the housing; an iron core disposed within the housing; and a first yoke disposed around the iron core and cooperating with the permanent magnet. an excitation coil that selectively switches the attraction part between an energized state and a de-energized state, and a second yoke disposed in the housing, the second yoke, the iron core, and the first yoke and the iron core, the first yoke and the second yoke, or
The housing and the second yoke together form a magnetic gap that acts as a leakage magnetic path for magnetic flux from the permanent magnet while the attraction part is in a non-excited state, A non-magnetic material is disposed in the magnetic gap, and the two members forming the magnetic gap include a plurality of screws that pass through one of the two members and the non-magnetic material and are screwed to the other of the two members. or a plurality of screws screwed into one of the two members and abutted on the other of the two members through the non-magnetic material. (2) A face plate that defines an attraction part that attracts a magnetic material, an electromagnet assembly that selectively switches the attraction part between an energized state and a de-energized state, and a permanent magnet that is disposed on one of the electromagnet assembly and the face plate. The electromagnet assembly includes a cylindrical housing, a first yoke disposed at one end of the housing and magnetically connected to the housing, and an iron core disposed within the housing. , an excitation coil disposed around the iron core and selectively switching the attracting section between an energized state and a de-energized state in cooperation with the permanent magnet, and a second yoke disposed within the housing, the second yoke and the iron core, the first yoke and the iron core, the first yoke and the second yoke, or
The housing and the second yoke together form a magnetic gap that acts as a leakage magnetic path for magnetic flux from the permanent magnet while the attraction part is in a non-excited state, A non-magnetic material is disposed in the magnetic gap, and the two members forming the magnetic gap include a plurality of screws that pass through one of the two members and the non-magnetic material and are screwed to the other of the two members. or a plurality of screws screwed into one of the two members and abutted on the other of the two members through the non-magnetic material.