JPH0215282Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a holding magnet used for holding magnetic metal materials used in metal processing and the like.

(Prior art) One of the holding magnets used for holding magnetic metal materials is a permanent magnet loaded in a circular cavity bored in a block made of a magnetic material, and a permanent magnet that is magnetically insulated from the block and inserted into the circular cavity. There is a holding magnet that includes a magnetic pole member disposed within the permanent magnet, one magnetic pole of the permanent magnet is in contact with the block, and the other magnetic pole is in contact with the magnetic pole member. This holding magnet is characterized by its simple structure and strong attractive force.

Generally, as shown in FIGS. 1 and 2, this type of holding magnet consists of a block 1 made of a magnetic material and a bottomed circle with a hole drilled in the block 1 so as to open at one end surface of the block. A permanent magnet 3 disposed within the cavity 2, a magnetic pole member 5 disposed within the circular cavity 2, an inner circumferential surface portion near the opening 4 of the block 1, and an outer circumferential surface portion of the corresponding portion of the magnetic pole member 5. and a non-magnetic pole member 6 filled in an annular gap formed by the above. The permanent magnet 3 is arranged so that one of its magnetic poles is in contact with the block 1 and the other is in contact with the magnetic pole member 5. The magnetic pole member 5 has an end surface that, together with the one end surface of the block 1, defines a magnetically active surface 7 that guides the magnetic flux of the permanent magnet 3 toward the object to be held. The permanent magnet 3 absorbs the frictional force between the block 1 and the non-magnetic member 6 and the magnetic pole member 5 and the non-magnetic member 6.
It is fixed and maintained within the circular cavity 2 by the frictional force between them.

However, in the conventional holding magnet as shown in FIGS. 1 and 2, the contact surface between the block 1 and the non-magnetic member 6 and the contact surface between the magnetic pole member 5 and the non-magnetic member 6 are aligned with the axis of the circular cavity 2. Since the permanent magnets 3 and 3 are parallel to each other, the frictional force between them is small, and therefore the fixing force for maintaining the permanent magnet 3 in the circular cavity 2 is weak, and the holding magnet often disintegrates during use. In particular, when the magnetically active surface 7 is molded to match the shape of the object to be held, the contact surface between the block 1 and the non-magnetic member 6 and the contact surface between the magnetic pole member 5 and the non-magnetic member 6 become even smaller, resulting in the above-mentioned defects. becomes noticeable.

(Purpose) The purpose of the present invention is to eliminate the defects of conventional holding magnets as described above and to provide a robust holding magnet that can reliably maintain a permanent magnet within a circular cavity. .

(Structure, Function, Effect) The holding magnet of the present invention is a block made of a magnetic material and has a bottomed circular cavity opening at one end surface, and a magnetic pole such that one magnetic pole is in contact with the block. a permanent magnet housed in the circular cavity; and a magnetic pole member disposed within the circular cavity and in contact with the other magnetic pole of the permanent magnet, which cooperates with the one end surface of the block to define a plane. A magnetic pole member having an end face and forming an annular gap by an inner circumferential surface portion of a portion of the block near the opening and an outer circumferential surface portion of a corresponding portion of the magnetic pole member; and a non-magnetic member disposed in the gap. The holding magnet is characterized in that the diameters of the inner circumferential surface portion and the outer circumferential surface portion defining the gap gradually increase toward the bottom of the circular cavity.

Since the diameters of the inner peripheral surface and the outer peripheral surface that define the gap gradually increase toward the bottom of the circular cavity, the diameter of the contact surface between the block and the non-magnetic member and the diameter of the contact surface between the magnetic pole member and the non-magnetic member are The diameter of the contact surface gradually increases toward the bottom of the circular cavity. Therefore, according to the present invention, since the permanent magnet can be firmly confined within the circular cavity by the action of the contact surface, not only a robust holding magnet can be obtained, but also a magnetic field tailored to the object to be held. The working surface can be easily molded.

(Example) Hereinafter, details of the present invention will be explained with reference to the drawings.

The holding magnet shown in FIG. 3, like the conventional holding magnet shown in FIGS. 1 and 2, includes a block 11 made of a magnetic material and a bottomed hole drilled into the block from one end surface. A permanent magnet 13 is magnetized in the axial direction of the circular cavity 12 and is disposed within the circular cavity 12 with one magnetic pole in contact with the bottom of the circular cavity 12, and a block is placed in contact with the other magnetic pole of the permanent magnet. A disk-shaped magnetic pole member 15 arranged in the opening 14 of 11
and an annular non-magnetic pole member 16 filled in an annular gap formed by the inner peripheral surface of the block 11 near the opening 14 and the corresponding outer peripheral surface of the magnetic pole member 15.

The end surface of the block 11 on the side of the opening 14, that is, one end surface, and the corresponding one end surface of the magnetic pole member 15 are on the same plane so as to define a magnetically active surface 17 together. The inner diameter of the portion of the block 11 that defines the gap and the outer diameter of the portion of the magnetic pole member 15 that defines the gap gradually increase toward the bottom of the circular cavity 12. As a result, as shown in FIG. 4, an inner circumferential surface portion 11' having a gradient θ' is formed near the opening 14 of the block 11, and an outer circumferential surface portion 15' having a gradient θ' is formed at the corresponding portion of the magnetic pole member 15. ing.

For example, as shown in FIG. 4, this holding magnet is constructed by holding a permanent magnet 13 in a circular manner such that one magnetic pole is in contact with the bottom of the circular cavity 12 of the block 11 and the other magnetic pole is in contact with the magnetic pole member 15. It is disposed within the cavity 12 and has an outer diameter equal to the minimum diameter of the inner circumferential surface portion 11' of the block 11 and an outer circumferential surface portion 15' of the magnetic pole member 15.
An annular non-magnetic member 16 having an inner diameter equal to the minimum diameter of the block 11 is press-fitted into an annular gap 18 defined by the inner peripheral surface 11' of the block 11 and the corresponding outer peripheral surface 15' of the magnetic pole member 15. It can be manufactured by

Here, the slope or angle θ of the inner peripheral surface portion 11' with respect to a line parallel to the axis of the circular cavity 12, the slope or angle θ' of the outer peripheral surface portion 15' with respect to a line parallel to the axis of the circular cavity 12, and the nonmagnetic member The inner and outer diameters of 16 are dimensions such that when the non-magnetic member 16 is press-fitted into the gap 18, the non-magnetic member 16 expands appropriately within a range that does not break and comes into close contact with the inner circumferential surface portion 11' and the outer circumferential surface portion 15'. selected. Preferred values of the angles θ and θ′ are:
Almost once or twice.

According to the above-mentioned holding magnet, the inner circumferential surface portion 1 of θ
1′ and the outer peripheral surface portion 15′ are each non-magnetic member 16.
and acts to generate a force that moves the magnetic pole member 15 toward the bottom of the circular cavity 12, and this force acts as a force that fixes the magnetic pole member 15 and the permanent magnet 13 within the circular cavity 12.

Another embodiment of the holding magnet is shown in FIG.

The holding magnet shown in FIG. 5 includes a block 21 made of a magnetic material, a cylindrical permanent magnet 23 disposed in a bottomed circular cavity 22 bored from one end surface of the block, and a circular permanent magnet 23. A cylindrical magnetic pole member 25 disposed within the cavity 22, an inner circumferential surface portion 21' near the opening 24 of the block 21, and a corresponding magnetic pole member 25.
an annular non-magnetic pole member 26 filled in an annular gap formed by the outer circumferential surface portion 25' of the portion;
It includes a disc-shaped non-magnetic member 28 disposed at the bottom of the circular cavity 22 and between the bottom surface of the magnetic pole member 25 and the block 21.

The permanent magnet 23 is magnetized in the radial direction of the circular cavity 22, and is arranged with its outer and inner circumferential surfaces in contact with the inner surface of the block 21 and the outer surface of the magnetic pole member 25, respectively. The end face of the block 21 on the opening 24 side, that is, one end face, and the magnetic pole member 25
The corresponding one end surface of the magnetically active surface 27 is coplanar so as to jointly define the magnetically active surface 27 .

The inner diameter of the inner circumferential surface portion 21' of the block 21 and the outer diameter of the outer circumferential surface portion 25' of the magnetic pole member 25 are also gradually increased toward the bottom surface of the circular cavity 22, as in the previous embodiment. Further, the slope or angle of the inner circumferential surface portion 21' with respect to a line parallel to the axis of the circular cavity 22, and
The slope or angle of the outer circumferential surface portion 25' with respect to a line parallel to the axis of is selected to be the same value as in the previous embodiment.

In the holding magnet shown in FIG. 5, the inner circumferential surface part 21' and the outer circumferential surface part 25' act to generate a force that moves the non-magnetic member 26 and the magnetic pole member 25 toward the bottom of the circular cavity 22, respectively. This force is applied to the magnetic pole member 2
5 and the permanent magnet 23 in the circular cavity 22.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a conventional holding magnet, Fig. 2 is a sectional view showing the conventional holding magnet shown in Fig. 1, and Fig. 3 is a sectional view showing an embodiment of the holding magnet of the present invention. , FIG. 4 is a cross-sectional view for explaining a method of manufacturing the holding magnet shown in FIG. 3, and FIG. 5 is a cross-sectional view showing another embodiment of the holding magnet of the present invention. 11, 21: Block made of magnetic material, 12, 2
2: Circular cavity, 13, 23: Permanent magnet, 14, 24:
Opening, 15, 25: Magnetic pole member, 16, 26: Non-magnetic member, 17, 27: Magnetic action surface, 11', 2
1': inner peripheral surface, 15', 25': outer peripheral surface.

Claims (1)

[Claims for Utility Model Registration] (1) A block made of a magnetic material having a circular cavity with a bottom that opens at one end surface, and a block in the circular cavity such that one magnetic pole is in contact with the block. a permanent magnet housed in the block, and a magnetic pole member disposed within the circular cavity and in contact with the other magnetic pole of the permanent magnet, having an end surface that defines a plane in cooperation with the one end surface of the block; A holder including a magnetic pole member that forms an annular gap between an inner circumferential surface of a portion near the opening of the block and an outer circumferential surface of a corresponding portion of the magnetic pole member, and a non-magnetic member disposed in the gap. A holding magnet, wherein the diameters of an inner circumferential surface portion and an outer circumferential surface portion defining the gap gradually increase toward the bottom of the circular cavity. (2) The magnetic pole member has a disc-like shape,
The permanent magnet has a columnar shape magnetized in the axial direction of the circular cavity, and one magnetic pole of the permanent magnet is in contact with the bottom surface of the circular cavity,
The holding magnet according to claim 1, wherein the other of the permanent magnets is in contact with a surface of the magnetic pole member on the bottom surface side. (3) the magnetic pole member has a cylindrical shape;
The holding magnet according to claim 1, wherein the permanent magnet is located outside the magnetic pole member and inside the block, and is magnetized in the radial direction of the circular cavity. .