JPS62167191A - Magnetic attraction holder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic attraction and holding device that makes it possible to erase residual magnetism.

(Prior art) A magnetic circuit consisting of an electromagnet or a permanent magnet of a magnetic attraction/holding device for lifting and fixing articles or raw materials made of magnetic materials is energized to attract and hold the object, and then the excitation is released to hold the object. When releasing the object, it has the disadvantage that it is not possible to release the object properly due to the residual magnetism of the magnetic circuit and the residual magnetism of the object.

For this reason, in conventional electromagnetic magnetic attraction and holding devices, demagnetization is performed by applying a reverse excitation current to the excitation coil or by applying an attenuating alternating current.

Further, in a magnetic attraction/holding device using a permanent magnet, a forced removal means such as applying a mechanical external force to the object is used.

(Problems to be Solved by the Invention) However, the conventional magnetic attraction and holding device has the following problems.

Applying reverse excitation current or attenuated alternating current to the excitation coil of an electromagnet requires complex control such as switching the polarity of the applied voltage and adjusting the excitation current, and it is difficult to control the circuit elements due to the huge inductance of the electromagnet. Appropriate protection devices must be added to protect it, and a complex and large power supply is required.

On the other hand, in the case of permanent magnets, a mechanical device must be added to forcibly separate them against residual magnetism, and the magnetic adsorption/holding device itself is large and expensive compared to its capacity. .

Therefore, the present invention aims to solve these problems and provides a magnetic attraction holding device that can completely release an object at the same time as demagnetization without using complicated excitation current control or forced release means. It is something to do.

(Means for Solving the Problems) The magnetic adsorption holding device according to the present invention has the following configuration in order to solve the above problems.

An excitation coil 10 as a magnetic generation source, and a magnetic pole 16 for attracting and holding formed on the end surface of a core 14 as a magnetic circuit member disposed in contact with both magnetic poles generated by a permanent magnet 12.
This magnetic attraction/holding device is capable of controlling the magnetic force of the magnet, and is characterized in that a permanent magnet 18 for erasing residual magnetism having a polarity opposite to the attraction/holding magnetic pole 16 is provided in a part of the magnetic circuit or in the vicinity. .

(Function) After the object 20 is attracted by magnetism, when the excitation to the magnetic pole for attraction and holding 16 is released, the magnetic pole for attraction and holding 16
The remaining magnetic flux in the same direction is canceled out by the magnetic flux of the permanent magnet 18 and disappears, releasing the object.

(Example) Preferred examples embodying the present invention will be described below in detail with reference to the drawings.

E-shaped core 14a with three legs extending downward as shown in FIG.
An excitation coil 1° is wound around the inner core portion 24 of the E-shaped core 14a, and a magnetic flux 26a, 2 that passes vertically through the center of the core is generated, with the left side in the hour hand rotation direction and the right side in the counter hour hand rotation direction.
6b. In addition, weak permanent magnets 18 and 18 for erasing residual magnetism are buried in a recess on both sides of the core portion 24 slightly above the lower end surface of the core portion 24 at the bottom of the core portion 24 in the center of the E-type core 14a. Left magnetic flux 28
The magnetic flux 28b on the right side is formed in the counterclockwise rotational direction of the hour hand, and the magnetic flux 26a, 26b and the magnetic fluxes 28a, 28b oppose each other and cancel each other out.

FIG. 2 differs from the embodiment described above in that the core shape is H-shaped. An excitation coil 10 is wound around a core member 3o extending in the left-right direction at the center of the H-shaped core 14b to form a magnetic flux in the counterclockwise rotating direction inside the lower part of the H-shaped core 14b. Core member 32.32 on which the H-shaped core 14b is erected
A permanent magnet 18 is placed inside the inner lower side of the
．． 18 is fixed using adhesive. The left permanent magnet 18 forms a magnetic flux in the hour hand rotation direction, and the right permanent magnet 18 forms a magnetic flux in the counter hour hand rotation direction.

To give another example, as shown in FIG. 3, a core 36 is screwed into the lower part of a bottomless, box-shaped hollow case 34 made of a magnetic material. A permanent magnet 12 is disposed inside a hollow case 34 so as to be movable up and down, a plate-shaped body 38 is fixed to the upper part of the permanent magnet 12, and an operating rod 40 is erected upward from the center of the plate-shaped body 38, and the hollow case 34 is vertically movable. A hole 42 through which an operating rod 40 is inserted is provided at the center of the upper part of the case 34. The upper part of the operating rod 40 is formed into a T-bar shape by a horizontal bar. The threaded portions on both sides of the upper portion of the core 36 are recessed, and the permanent magnets 18 and 18 are fixed therein. In this case, by moving the operating rod 40 up and down, magnetic flux extinction and excitation can be repeated. The permanent magnet 18 can be provided in the vicinity of part or all of the magnetic pole for attracting and holding other than the holding surface, and a rubber magnet, a ferrite rare earth magnet, or the like can be used. The figure (a) shows the attracted state, and the figure (b) shows the released state, in which the permanent magnet 12 has retreated to a position where the magnetic flux cannot affect the core 36 through the space 44. Further, the permanent magnet 18 constantly generates magnetic flux 46.

To give yet another example, the permanent magnet 18 may not only be provided in contact with the magnetic circuit member, but may also be provided on the entire surface of the magnetic pole or on the side, since it is sufficient to simply cancel residual magnetism. A non-magnetic material may be interposed.

The counter-electromotive force generated by the permanent magnet 18 does not need to be strictly defined (although even if it is made slightly stronger than the residual magnetism, the object will easily separate when the magnetic fields of both magnetic poles cancel each other out and become zero during demagnetization.

FIG. 4 shows a magnetic curve diagram when the magnetic attraction and holding device is in an excited state. Let U be the original magnetomotive force of the magnetic source. The magnetic flux φ induced in the device in this case is the loop ABCDEA
The intersection point P1 between the line and the operating line determined by the permeance between the device and the object.

Next, when the excitation is cut off and the magnetomotive force is made zero, k moves to G-0, and the magnetic flux φ becomes P2, which decreases but slightly restrains the object.

Due to the arrangement of the micromagnets, k moves to a position starting from the 0 point due to the counter-electromotive force -U applied to the micromagnets, a part of the magnetic circuit member of the device, and the object, and the magnetic flux φ becomes the intersection point P3. It becomes zero.

In this figure, the values in the X direction of the loop are enlarged for clarity of explanation.

The counter-electromotive force −U exerted by the small magnet is the magnetic flux during excitation, Pl
Although it decreases from Pl to Pl, it is not large enough to be a problem in practice.

(Effects of the Invention) As described above, according to the present invention, the object can be reliably removed without requiring an expensive device such as a degaussing adjustment circuit, and its operation is semi-permanent, extremely inexpensive, and simple. In addition to being simple in structure, it also has the advantage of being applicable to electrode chucks.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of drawings]

1, 2, and 3 are front sectional views of the magnetic attraction and holding device, and FIG. 4 is a magnetic curve diagram. 10... Excitation coil, 12... Permanent magnet, 14...
...Core, 14a, 14b...E type core, 1
6...Magnetic pole for attracting and holding, 1B...Permanent magnet, 20
...Object, 24...Core part, 26a, 26
b=magnetic flux, 28a, 28b... magnetic flux, 30... core member,
32... Core member, 34... Hollow case, 36
... core, 38 ... plate-shaped body, 40 ... operation rod,
42... Hole, 44... Space, 46... Magnetic flux.

Claims (1)

[Claims] 1. A magnetic attraction and holding device capable of controlling the magnetic force of magnetic poles for attraction and holding formed on the end face of a magnetic circuit member disposed in contact with both magnetic poles of a magnetic generation source, which A magnetic attraction/holding device characterized in that a magnetic circuit is provided with a permanent magnet for erasing residual magnetism having a polarity opposite to a magnetic pole for use. 2. The magnetic attraction and holding device according to claim 1, wherein the magnetic generation source is an electromagnet. 3. The magnetic attraction holding device according to claim 1, wherein the magnetic generation source is a permanent magnet, and the magnetic force generated in the holding magnetic pole is controlled by switching the magnetic circuit device from the outside. 4. The magnetic attraction and holding device according to claim 1, 2 or 3, wherein the permanent magnet for erasing residual magnetism is a high coercive force magnet.