JPH01171737A - Permanent magnet chuck - Google Patents

Abstract

PURPOSE:To eliminate magnetic leakage and concentrate a holding force upon a held object by surrounding the faces except adsorbing faces for adsorbing the held object out of magnetic poles placed in a box shaped frame with permanent magnets. CONSTITUTION:The adsorbing faces 5 of magnetic poles 7 on permanent magnets 3 are formed at a level with the peripheral end face of a magnetic frame 2, and magnetic separators 4 having the same thickness as the permanent magnet 3 are fitted in the gaps between each permanent magnet 3 and the gaps between the inner walls of the frame 2 and the permanent magnets 3. The permanent magnets 3 opposite to each magnetic pole 7 are fitted in the gaps across which each magnetic pole 7 is opposed to the other and in the gaps across which each magnetic pole 7 is opposed to the inner walls of the frame 2 on the top of each magnetic separator 4, and the heights thereof are such that they form step faces 6 which are slightly lower than the adsorbing faces of the magnetic poles 5. Magnetic separators 4 are fitted to the stepped faces 8 and the four corners of the frame 2 so as to be flush with the adsorbing faces 5. Thus, in the chuck 1, since the lines of magnetic force directed from N to S surround the faces except the adsorbing faces 5 of the magnetic poles 7, no magnetic leakage will occur except the generated lines of magnetic force on the adsorbing face 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a permanent magnet chuck used for fixing a workpiece in a machine tool or the like.

[Conventional technology]

Recently, permanent magnet chucks have been used that attract nearly non-magnetic materials that are difficult to attract magnetically.

This permanent magnet chuck is used to fix a relatively small object, and does not have a switching function for applying or not applying a coercive force to the object. Examples of this permanent magnet chuck include those shown in FIGS. 6 and 7. A permanent magnet chuck 1 shown in FIG. 6 has permanent magnets 3 arranged within a box-shaped magnetic frame 2, and the permanent magnets 3 are partitioned by magnetic separators 4 made of non-magnetic material. This attracting surface 5 has a different polarity arrangement in which the N-pole side and the S-pole side of the permanent magnet 3 are alternately arranged. The permanent magnet chuck 1 shown in FIG. 7 has a permanent magnet 3 inside a magnetic frame 2 partitioned into a box shape.
are arranged surrounded by a magnetic separator 4. This attracting surface 5 has a homopolar arrangement in which the N pole side of the permanent magnet 3 is arranged.

[Problem that the invention seeks to solve]

However, although the conventional permanent magnet chucks mentioned above have a structure that minimizes magnetic leakage by separating the permanent magnets with magnetic separators, the permanent magnets appear on the suction surface, making it difficult to process the suction surface. There is a drawback. Another drawback is that permanent magnets appear on the suction surface, making machining of the suction surface difficult. Furthermore, in order to attract nearly non-magnetic materials, it is necessary to increase the coercive force, which is not sufficient as a countermeasure against magnetic leakage.

The present invention has been made in order to solve the above-mentioned problems, and provides a permanent magnet chuck that has a highly workable attracting surface, eliminates magnetic leakage, and can concentrate coercive force on an object to be held. The purpose is to

[Means for solving problems]

In order to achieve the above object, the present invention arranges a magnetic pole in a box-shaped frame, and surrounds the surface of the magnetic pole other than the attracting surface that attracts the object with a permanent magnet.

[For production]

In the permanent magnet chuck configured as described above, the magnetic poles are surrounded by permanent magnets except for the attracting surface, so the lines of magnetic force from the attracting surface are directed only toward the object to be held, and there is no magnetic leakage.

〔Example〕

The permanent magnet chuck of the present invention will be explained below based on the drawings. FIG. 1 shows an embodiment of a permanent magnet chuck 1 according to the present invention, and shows a cross section of the permanent magnet chuck 1. As shown in FIG.

Since this permanent magnet chuck 1 has the same structure as that already explained in the section of the prior art based on FIGS. 6 and 7, the same reference numerals are given to these parts and detailed explanation will be omitted.

The magnetic frame 2 of the permanent magnet chuck 1 is box-shaped with a bottom 6. The plurality of magnetic poles 7 arranged at predetermined intervals within the magnetic frame 2 are rectangular parallelepipeds, as also shown in FIG. Each magnetic pole 7 is placed on a rectangular parallelepiped permanent magnet 3 having an area equal to the bottom area of the magnetic pole 7. The attraction surface 5 of the magnetic pole 7 placed on the permanent magnet 3 is formed parallel to the peripheral end surface of the magnetic frame 2. A magnetic separator 4 having the same thickness as the permanent magnet 3 is fitted into the gap between each of the permanent magnets 3 described above and the gap between the inner wall of the magnetic frame 2 and the permanent magnet 3. Permanent magnets 3 facing each magnetic pole 7 are fitted on the upper surface of the magnetic separator 4 in the gap where each magnetic pole 7 faces each other, and in the gap between each magnetic pole 7 and the inner wall of the magnetic frame 2. It is. The height of these permanent magnets 3 forms a step surface 8 which is somewhat lower than the attraction surface of the magnetic pole 7.

A magnetic separator 4 is fitted into the stepped surface 8 and the four corners of the magnetic frame 2 so as to form a surface that coincides with the attracting surface 5 of the magnetic pole 7 .

Note that the permanent magnet 3 is a ferrite magnet or rare earth magnet with high coercive force.

FIG. 3 shows another example of the permanent magnet chuck 1, in which a regular cubic magnetic pole 7 is used.

FIG. 4 shows another example of the permanent magnet chuck 1, in which the magnetic pole 7 is cylindrical.

In this case, the magnetic separator 4 (the permanent magnet does not necessarily have to be cylindrical) is a cylindrical magnet t! 1i
Manufactured to fit I7.

FIG. 5 shows a state in which the permanent magnet 3 in contact with the lower surface of the magnetic pole 7 shown in FIGS. 2, 3, and 4 moves in the direction of the arrow to the lower surface of the adjacent magnetic pole 7. Due to this movement, the attraction surface 5 of the magnetic pole 7 has a switching function that allows it to be strengthened or weakened depending on the polarity relationship with the permanent magnet 3 on the side surface.

In the permanent magnet chuck 1 configured as described above, as shown in FIGS. 1 to 4, the lines of magnetic force from the N pole to the S pole surround each surface of the magnetic pole 7 except for the attraction surface 5, and the attraction There is no magnetic leakage other than lines of magnetic force generated from the surface 5.

〔Effect of the invention〕

From the above, the permanent magnet chuck of the present invention has a structure in which the other surfaces of the magnetic pole except the attracting surface are surrounded by permanent magnets, so the magnetic force lines of the permanent magnet surround the magnetic pole, and the other surfaces except the attracting surface are surrounded by permanent magnets. Magnetic leakage from the magnetic field can be eliminated, and the magnetic field can be concentrated on the attracting surface. As a result, the lines of magnetic force from the attracting surface of the magnetic pole act only on the object to be held, so that the coercive force for holding the object can be increased.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the permanent magnet chuck of the present invention, FIG. 2 is a plan view shown by arrow A-A in FIG. 1,
FIG. 3 is a plan view showing another example of the permanent magnet chuck of the present invention, FIG. 4 is a plan view showing another example of the permanent magnet chuck of the present invention, and FIG. 5 is a plan view showing another example of the permanent magnet chuck of the present invention. A sectional view showing an example of moving a permanent magnet in the direction of the arrow, and FIGS. 6 and 7 are sectional views showing a conventional permanent magnet chuck. DESCRIPTION OF SYMBOLS 1... Permanent magnet chuck, 2... Frame (magnetic frame), 3... Permanent magnet, 4... Non-magnetic material (magnetic separator), 5... Attraction surface, 7... Magnetic pole. Applicant's agent Mr. Sato

Claims (1)

[Claims] 1. A permanent magnet chuck, characterized in that a magnetic pole is arranged in a box-shaped frame, and the surface of the magnetic pole other than the attracting surface that attracts the object to be held is surrounded by permanent magnets. 2. The permanent magnet chuck according to claim 1, wherein a non-magnetic material is formed in a space other than the magnetic poles and permanent magnets arranged in the frame. 3. The permanent magnet chuck according to claim 1, wherein the magnetic pole has a cylindrical shape with an attraction surface on one side. 4. The permanent magnet chuck according to claim 1, wherein the permanent magnet disposed between the bottom of the frame and the magnetic pole is movable to another adjacent magnetic pole.