JPH10179611A - Production of denture attachment magnet structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a denture attachment which can improve productivity and production yield and can increase magnetic attracting force by securing a stable non-magnetic area. SOLUTION: In forming a non-magnetic seal ring part 17 of a seal plate 18 of this denture attachment magnet structure 1 to be attracted to a keeper attached at the root part by magnetic attracting force, Ni, Mn, or Ni-Mn alloy film is formed on the circumference side of the seal plate 18, and after that, it is alloyed by thermal diffusion and the non-magnetic seal ring part 17 is formed. Then the real plate 18 is brought into contact with a yoke 12 and the magnet 11, and the contact part of the yoke 12 and the seal plate 18 is connected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a small magnetic attachment magnet structure capable of securing a required magnetic attraction force within a limited denture base.

[0002]

2. Description of the Related Art Conventionally, as a denture attachment utilizing magnetic attraction, for example, the one shown in FIGS. 3 and 4 has been proposed (Japanese Patent Laid-Open No. Hei 4-227253). As shown in FIG. 3, a root plate 5 buried in the root 6 is buried, and a keeper 9 is further buried therein. The denture 80 has a denture attachment 8 facing the keeper 9, and comprises a resin bed 3 and an enamel-like artificial tooth 4 surrounding it.

As shown in FIG. 8, the denture attachment 8 includes a columnar permanent magnet 81 magnetized in a direction in which a magnetic flux intersects an attraction surface which comes into contact with a keeper, and a concave case made of a corrosion-resistant magnetic material. A corrosion-resistant non-magnetic shield ring 87 and a corrosion-resistant metal seal plate 86 which are housed in the case 82 and are arranged concentrically with respect to the columnar permanent magnet are mounted inside the concave case so that the permanent magnet is not exposed. The upper part of the case is covered, and the butted portions of the case 82, the seal ring 87, and the seal disk 86 are seam-welded. The shield ring 87 and the metal seal plate 86 are collectively called a seal plate 88.

[0004]

In the manufacturing method described in this publication, the butted portions of the outer periphery of the case 82 and the shield ring 87, the inner periphery of the shield ring 87 and the metal seal plate 86 are laser-welded. Was. When such welding is performed, air gaps or irregularities occur at the butted portion between the case 82 and the outer periphery of the shield ring 87 due to distortion due to heat at the time of welding. There is a problem that laser welding is difficult at a butt portion with the seal plate 86 and that a welding crack is easily generated. In addition, there is a problem that variations in the assembly dimensions are increased.

In order to solve these problems, a manufacturing method as shown in FIG. 5 has been proposed in p. 408 of the Abstract of the Japan Institute of Metals (September 29, 1996).
In the manufacturing method disclosed in this document, a magnet 81a is housed in a cup yoke 82a, a Ni film 85a is applied in advance to a side surface of a disk yoke 84a, and a lid is covered with the disk yoke 84a. The welded portion 87a is made non-magnetic by melting the joint between the disk yoke 84a and the disk during welding. As a result, it is reported that the laser welding only needs to be performed once, so that the number of times of welding can be omitted once, and the accompanying problems have been solved. Furthermore, the number of parts is reduced and the process is simplified.

However, this manufacturing method has the following disadvantages. If the disk yoke 84a with the Ni coating 85a is made larger and fitted into the opening of the cup yoke 82a, peeling may occur due to insufficient adhesion due to plating. As a result, the production yield and productivity may be reduced, or the demagnetization of the molten portion may be insufficient due to an insufficient amount of Ni. Also, Ni
When the disk yoke 84a with the film 85a is made smaller and inserted into the opening of the cup yoke 82a, solidification shrinkage occurs toward the end during the circular welding, and the gap gradually increases, and finally the gap increases. In some cases, welding becomes impossible due to solidification shrinkage strain and the action of gaps. As a result, productivity and production yield naturally declined. So in this method,
Even if the size of the disk yoke 84a with the Ni coating 85a is adjusted, there is a problem that it cannot be manufactured satisfactorily.

Further, in this manufacturing method, in order to melt the Ni film 85a, it is necessary to take a melting depth corresponding to the thickness of the disk yoke 84a. Therefore, compared with the conventional simple welding, the fusion zone becomes larger, and the solidification shrinkage is large, which causes cracking. Furthermore, melting by laser is instantaneous because of high energy density, segregation occurs because it is not sufficiently stirred,
Soft magnetic portions are locally generated. Therefore, the effect of the non-magnetic portion becomes insufficient, and the cup yoke 82a and the disc yoke 84
The magnetic attraction force is degraded due to the increase in the magnetic flux passing between a. The technique of FIG. 5 has the above problems. As described above, in the manufacturing method of the present denture attachment, the productivity and the production yield at the time of assembling are improved, the good joining of the fusion zone, the production yield by preventing cracks, the productivity is improved, and the stable non-magnetic area is improved. It has been demanded that the magnetic attraction force be improved by securing.

[0008]

As a solution to this problem, the inventor of the present invention has proposed a method of changing the shape of the non-magnetic portion between the disk yoke 84a and the opening of the cup yoke 82a and the various manufacturing methods for the non-magnetic region. Investigating the solidification shrinkage, joint state, weld cracking state, component segregation state, and magnetic attraction force of the part, and as a result of intensive research, the production yield by preventing the peeling of the Ni plating film, improvement in productivity, good melting part The present invention has been found out a method of manufacturing a magnet structure of a denture attachment in which the production yield and the productivity are improved by preventing a strong joining and welding cracks, and the magnetic attraction force is improved by securing a stable non-magnetic region.

According to a first aspect of the present invention, there is provided a magnet body which is buried in a denture base so as to face a keeper provided at a root portion and has an NS pole in a direction in which a magnetic flux intersects an attraction surface contacting the keeper. A yoke made of a soft magnetic material that accommodates the magnet body in substantially the same manner, and further has a seal plate that is in contact with the magnet body and that serves as an attraction surface that magnetically attracts the keeper. A non-magnetic shield ring portion forming a ring portion, and a soft magnetic shield portion inscribed therein, wherein an outer peripheral portion of the non-magnetic shield ring portion and an inner peripheral surface of the yoke come into close contact with the keeper, and the keeper When the non-magnetic shield ring portion of the seal plate is manufactured, the outer periphery of the soft magnetic shield plate is used in a denture attachment magnet structure that is attracted by magnetic attraction to the magnetic plate. Ni on the surface, Mn or Ni-
A Mn alloy film layer is formed, then alloyed by a thermal diffusion process to form a non-magnetic shield ring portion, the shield plate is brought into contact with the yoke and the magnet body, and the yoke and the seal plate are brought into contact. And a method of manufacturing a magnet structure, which comprises joining parts.

According to a second aspect of the present invention, there is provided a method of manufacturing a magnet structure according to the first aspect, wherein the contact portion between the yoke and the seal plate is joined by laser welding, electron beam welding, or brazing. It is.

When the magnet structure is manufactured by such a manufacturing method, since the nonmagnetic portion formed by thermal diffusion is caused by diffusion, the composition is uniform and a complete nonmagnetic region is formed.
Further, since the non-magnetic portion is formed by diffusion, it is alloyed unlike mere plating, and the adhesion is remarkably excellent. Therefore, even if a disk yoke having an alloyed non-magnetic region is made large and fitted, the non-magnetic region does not peel off. Therefore, when welding is performed by welding, a disc yoke having a non-magnetic region can be fitted, so that there is no gap between the non-magnetic region and the cup yoke, and the gap does not gradually expand during circuit welding by laser and electron beam welding. . Since the non-magnetic region has already been formed, the penetration depth can be made small enough to ensure the sealability without the need for complete melting of Ni and the possibility of corrosion, so that the amount of solidification shrinkage can be reduced and the solidification shrinkage strain can be reduced. Therefore, during round welding, solidification shrinkage occurs toward the end, and finally the gap does not become large and cannot be joined, and cracking does not occur due to solidification shrinkage distortion and the action of the gap.

Naturally, since the non-magnetic region is not peeled off by the insertion, it is not necessary to make the disk yoke having the non-magnetic region smaller, and when it is made smaller and inserted, there is no possibility of joining or cracking during round welding. . As described above, according to the method for manufacturing the denture attachment, it was possible to obtain a good joining of the fusion zone, a production yield by preventing cracks, an improvement in productivity, and an improvement in magnetic attraction force by securing a stable non-magnetic region. . When the joining is performed by brazing, naturally, since there is no welding step, a stable non-magnetic region is utilized as it is, and problems such as welding cracks do not occur.
Similarly, even if a disk yoke having an alloyed non-magnetic region is made larger and fitted, the non-magnetic region does not peel off.

The magnet used in the present invention is a magnet having a high magnetomotive force per unit volume.
Rare-earth magnets with high energy products such as -Fe-B system are good. The shape is a cylinder and the NS pole or SN pole extends in the direction in which the magnetic flux intersects the attracting surface that contacts the keeper.

A cup yoke and a disk yoke having an opening made of a corrosion-resistant soft magnetic material for accommodating a magnet have a necessary corrosion resistance so as not to cause a problem in use in the oral cavity, and have a magnetic flux from the magnet. It is necessary to have excellent magnetic properties in order to form a magnetic circuit for transmitting the magnetic field. The material used for the yoke includes 18Cr stainless steel,
Corrosion-resistant soft magnetic materials such as Cr-2Mo and 19Cr-2Mo stainless steels are preferred.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be shown in Examples.

[0016]

1 is a longitudinal sectional view showing an embodiment of a semi-finished product and a product in each production process of a denture attachment 1 produced by the production method of the present invention. FIG. 1A shows Step 1
The soft magnetic shield plate 14, which is a semi-finished product made of the above, is shown. The soft magnetic shield plate 14 is usually made by cutting a round bar. The material is 19Cr-2Mo-Ti steel with dimensions of 3.38 mm outer diameter and 0.15 mm thickness. FIG. 1 (b)
Shows a soft magnetic shield plate with Ni plating 15 which is a semi-finished product made in step 2 of Ni plating. The Ni plating thickness is 30 μm. The Ni plating 15 is applied along the outer peripheral side surface of the soft magnetic shield plate 16. The film layer, which is an element supply source for demagnetization, can be formed by various deposition methods such as sputtering, CVD, and PVD in addition to the plating step. Further, the components of the film layer are, in addition to Ni, Mn, Ni-Mn.
Alloy, Ni-Cr alloy, Mn-Cr alloy may be used. Further, the metal material may contain Fe or the like.

FIG. 1C shows a seal plate 18 which is a semi-finished product formed in step 3 which is a heat diffusion process. The seal plate 18 includes a non-magnetic shield ring 17 and a soft magnetic shield 16. The thermal diffusion conditions are as follows.
The holding temperature was kept at 1250 ° C. for 7 hours, the atmosphere was evacuated, and Ar gas was kept at 400 torr. Cooling was performed by Ar quenching. With this heat treatment, the Ni element of the 15 layers of Ni plating is thermally diffused to form the soft magnetic shield plate 14.
Then, a non-magnetic shield ring portion 17 having a uniform component was finally completed. The dimension of the non-magnetic shield ring 17 is a surface layer having a thickness of 50 μm. The seal plate 18 has an outer diameter of 3.44 mm and a thickness of 0.1.
5 mm. The holding temperature may be from 800 to 1400 ° C., and the holding time may be from 1 hour to 50 hours. At a low temperature, there is a problem in productivity because a long holding time is required, and at a high temperature, there is a problem of exhaustion of a furnace body of a heat treatment furnace. The atmosphere may be an inert atmosphere or a reducing atmosphere. For example, it may be performed in an atmosphere of Ar, He, vacuum and hydrogen gas.

FIG. 1D shows a step 4 of fitting or caulking the seal plate 18 into the yoke 12 containing the magnet body 11. Step 4 includes a magnet body 11 magnetized in the vertical direction of the drawing and a yoke 12 for housing the magnet body 11 in substantially the same manner.
On the other hand, this is a step of fitting or caulking the seal plate 18 created in Step 3 to a surface surrounded by the opening inner surface 121 of the yoke 12 and the S pole surface 111 of the magnet body 11. By fitting, the outer peripheral side surface 18 of the seal plate 18 created in the step 3 with respect to the inner surface 121 of the opening of the yoke 12.
1 is closely attached. In the yoke 12, the material is 19C
It is an r-2Mo-Ti steel with dimensions of an outer diameter of 4.4 mm, an inner diameter of 3.4 mm, a height of 2.1 mm, and a depth of 1.6 mm. In the magnet body 11, the material is an Nd—Fe—B based rare earth magnet having a maximum energy product (BHmax) of 40 MG.
Using Oe, dimensions are outer diameter 3.3mm, height 1.45m
m. FIG. 1E shows an example of a joining process for fitting and caulking in step 4 to make the closely contacted portion watertight. Step 5 includes opening the inner surface 121 of the yoke 12.
And outer peripheral side 1 of shield plate 18 created in step 3
In this step, a portion in close contact with 81 is irradiated with a laser beam from the upper vertical direction to be water-tight. The shape of the welding portion 19 is a welding width of 0.1 mm and a welding depth of 0.1 mm.

Further, if the steps 1 and 2 are prepared as follows, the productivity is further improved. In step 1 ′, the same Ni plating 15 as in step 2 is applied to a round bar having the same diameter as the soft magnetic shield plate 14. In step 2 ', the round bar is sliced as shown in FIG. Steps 1 and 2
It is difficult to apply Ni plating along the outer peripheral surface of the soft magnetic shield plate 16 as shown in FIG. Therefore, a polishing step is often performed finally, which is not practical. By manufacturing as described above, the productivity and the production yield at the time of assembling are improved, the joining of the molten portion is improved, the production yield by preventing cracks, the productivity is improved, and the magnetic attraction is ensured by securing a stable non-magnetic region. I was able to meet the power improvement.

[0020]

Comparative Example FIG. 2 is a longitudinal sectional view showing an example of a semi-finished product and a product in each manufacturing process of the denture attachment 8 manufactured by a conventional manufacturing method. The dimensions and materials of each component are the same as those of the embodiment, and only the manufacturing method is changed. FIG. 2A shows a soft magnetic shield plate 84a which is a semi-finished product formed in the step 1. Soft magnetic shield plate 84
a is usually made by cutting from a round bar. The material is 19Cr
-2Mo-Ti steel with dimensions of 3.26 mm outer diameter and 0.15 mm thickness. FIG. 1B shows a soft magnetic shield plate with Ni plating 85a, which is a semi-finished product made in step 2 of Ni plating. The Ni plating thickness is 50 μm. The Ni plating 85a is applied along the outer peripheral side surface of the soft magnetic shield plate 84a. The soft magnetic shield plate 84a with Ni plating 85a is integrally formed with an outer diameter of 3.36 mm and a thickness of 0.1.
5 mm.

FIG. 2C shows a soft magnetic shield plate 84 provided with a Ni plating 85a on a yoke 82a containing a magnet body 81a.
3 shows a step 3 of positioning a. In step 3, the magnet body 81a magnetized in the vertical direction of the paper surface and the magnet body 81a
Yoke 82a for the yoke 82a
Opening inner surface 821a and S pole surface 811a of magnet body 81a
Ni plating 85 created in step 2 for the surface enclosed by
This is a step of positioning the soft magnetic shield plate 84a with a. In the yoke 12, the material is 19Cr-2Mo-
Ti steel with dimensions of 4.4mm outside diameter and 3.4m inside diameter
m, height 2.1 mm, depth 1.6 mm. Magnet body 1
In No. 1, the material is an Nd—Fe—B based rare earth magnet, the maximum energy product (BHmax) of which is 40 MGOe,
The dimensions are an outer diameter of 3.3 mm and a height of 1.45 mm.

Normally, the soft magnetic shield plate 84a with the Ni plating 85a is formed with 3.36 mm, which is slightly smaller than the inner diameter of the yoke of 3.4 mm as described in the step 2 because the Ni plating is peeled off when the fitting is inserted during positioning and insertion. doing. Therefore, a gap of 0.02 to 0.04 mm is formed although it can be easily fitted.

FIG. 2 (d) shows the N inserted and positioned in step 3.
Step 4 shows an example of a joining step for making the gap between the outer peripheral side surface 851a of the soft magnetic shield plate 84a with the i-plate 85a and the opening inner surface 821a of the yoke 84a watertight. Step 4 is a step in which a gap between the inner surface 821a of the opening of the yoke 84a and the outer peripheral side surface 851a of the soft magnetic shield plate 84a with the Ni plating 85a formed in Step 2 is watertight by irradiating a laser beam from the upper vertical direction. is there. The shape of the welding portion 19 is a welding width of 0.20 mm and a welding depth of 0.15 mm. As a result, as shown in FIG. Furthermore, the content of the Ni element in the melted portion also fluctuates greatly in terms of components.
Is too high, it becomes a component similar to the high magnetic permeability material permalloy, becomes soft magnetic, and a complete nonmagnetic shield ring portion was not formed.

When the examples of the present invention are compared with the comparative examples, the present invention is superior in terms of the weldability of the fusion zone and the prevention of weld cracking, so that the production yield and productivity are superior. Further, the present invention was more excellent in securing a stable nonmagnetic region, and was able to satisfy the improvement of the magnetic attractive force.

[0025]

[Effect] By applying the manufacturing method of the present invention to the manufacture of the magnet structure of the denture attachment, the production yield by preventing the peeling off of the Ni plating film, the improvement of the productivity, the good joining of the fusion zone, and the production by preventing the welding crack are produced. It was possible to improve the yield, the productivity, and the magnetic attraction force by securing a stable non-magnetic region.

[0026]

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a manufacturing process of a denture attachment magnet structure of an embodiment. (A) Manufacturing process 1 of a denture attachment magnet structure of an embodiment. (B) Manufacturing process 2 of a denture attachment magnet structure of an embodiment. Manufacturing process 3 of the denture attachment magnet structure of the embodiment 3 (d) Manufacturing process 4 of the denture attachment magnet structure of the embodiment (e) Manufacturing process 5 of the denture attachment magnet structure of the embodiment

FIGS. 2A and 2B are explanatory views of a manufacturing process of a denture attachment magnet structure of a comparative example. (A) Manufacturing process 1 of a denture attachment magnet structure of a comparative example. (B) Manufacturing process 2 (c) of a denture attachment magnet structure of a comparative example. Manufacturing process 3 of the denture attachment magnet structure of the comparative example (d) Manufacturing process 4 of the denture attachment magnet structure of the comparative example

FIG. 3 is an explanatory view of a conventional denture.

FIG. 4 is an explanatory view of a conventional denture attachment.

FIG. 5 is an explanatory view of a conventional denture attachment. (A) State before laser melting (b) State after laser melting

[Explanation of symbols]

 1. . . 10. Denture attachment magnet structure of the present invention . . Magnet body 111. . . 11. S pole side bottom surface of magnet body . . Yoke 121. . . Inner surface of yoke 14. . . Soft magnetic shield plate 15. . . Ni plating film layer 16. . . Soft magnetic shield 17. . . Non-magnetic shield ring part 18. . . Seal plate 181. . . Seal plate side face 19. . . Laser melting part 3. . . Resin floor 4. . . Artificial teeth 5. . . Root plate 6. . . 7. Root portion . . Conventional Denture Attachment Magnet Structure 81. . . Permanent magnet 82. . . Concave case 86. . . Corrosion resistant metal seal plate 87. . . Corrosion resistant non-magnetic shield ring 88. . . Seal plate 8a. . . Conventional Denture Attachment Magnet Structure 81a. . . Magnet body 811a. . . S-pole side bottom surface of magnet body 82a. . . Cup case 821a. . . Cup yoke inner surface 84a. . . Disk yoke (before welding) 85a. . . Ni coating 851a. . . Side surface of disk yoke with Ni coating 86a. . . Disk yoke (after welding) 87a. . . Corrosion-resistant non-magnetic shield ring part 88a. . . Seal plate 9. . . Conventional keeper . . Denture

Claims (2)

[Claims] 1. A magnet body which is buried in a denture base so as to face a keeper provided at a root portion and has an NS pole in a direction in which a magnetic flux intersects an attraction surface which abuts the keeper, and a magnet body. A yoke made of a soft magnetic material housed in the same
A seal plate which is in contact with the magnet body and which serves as an attraction surface for magnetically attracting the keeper, the seal plate being a non-magnetic shield ring forming an outer peripheral ring thereof, and a soft magnetic shield inscribed therein; An outer peripheral portion of the non-magnetic shield ring portion and an inner peripheral surface of the yoke are brought into close contact with the keeper, and are attracted to the keeper by magnetic attraction. When manufacturing the non-magnetic shield ring portion in the above, a Ni, Mn or Ni-Mn alloy film layer is formed on the outer peripheral side surface of the shield plate, and then alloyed by a thermal diffusion process to form a non-magnetic shield ring portion. The method is characterized in that a shield plate is brought into contact with the yoke and the magnet body, and a contact portion between the yoke and the seal plate is joined. Method for producing a magnet structure to. 2. The method for manufacturing a magnet structure according to claim 1, wherein the contact portion between the yoke and the seal plate is joined by laser welding, electron beam welding, or brazing.