WO2005077297A1

WO2005077297A1 - Denture attachment and method of manufacturing the same

Info

Publication number: WO2005077297A1
Application number: PCT/JP2005/002645
Authority: WO
Inventors: Akira Kikuchi
Original assignee: Neomax Co., Ltd.
Priority date: 2004-02-18
Filing date: 2005-02-18
Publication date: 2005-08-25
Also published as: TW200528069A; JP4288505B2; TWI300709B; KR20060120275A; KR100808357B1; JP2005261939A; CN1917828B; CN1917828A

Abstract

A denture attachment, comprising a permanent magnet, a cup-like yoke formed of a corrosive resistant soft magnetic material having a recessed part for storing the permanent magnet, and a seal plate fitted to the opening part of the recessed part of the yoke. The seal plate further comprises a plate-like yoke formed of the corrosive resistant soft magnetic material and a seal ring formed of a corrosive resistant non- magnetic material disposed on the outer periphery of the plate-like yoke. The denture attachment is characterized in that the seal plate is joined to the yoke by a plurality of spot welded parts in which at least a butted part between the yoke and the seal ring is fixed and at least one welding-all-around part formed to cover the butted part between the yoke and the seal ring and the butted part between the seal ring and the plate-like yoke so as to seal the permanent magnet.

Description

Specification

Denture attachment and method of manufacturing the same

Technical field

[0001] The present invention relates to a denture attachment for holding a denture using magnetic attraction by a permanent magnet.

And a method for producing the same.

Background art

Japanese Patent Application Laid-Open No. 4-227253 discloses a denture attachment 400 having a permanent magnet 402 therein and embedded in a denture base 420 and an alveolar 421 as shown in FIGS. 24 and 25. A denture 430 having a soft magnetic keeper 423 installed on the root plate 422 and held on the root plate 422 by the magnetic attraction of the permanent magnet 402 and the keeper 423 is disclosed. In the denture attachment 400, a soft magnetic stainless steel sealing disk 414 and a nonmagnetic stainless steel sealing ring 415 are concentrically arranged at the opening of a cup-shaped yoke 401 made of soft magnetic stainless steel. The permanent magnet 402 is hermetically sealed by welding the entire circumference between the disc 414 and the seal ring 415 and between the seal ring 415 and the cup-shaped yoke 401. The denture attachment 400 can satisfy requirements such as being harmless to the human body, being chemically stable for a long period of time, and having a large adsorption force V.

[0003] Due to such a structure, the magnetic attachment 400 shown in Fig. 25 has a slight gap between the cup-shaped yoke 401 and the seal ring 415 due to variations in the dimensions of the cap before welding. You. In the welding of the cup-shaped yoke 401 and the seal ring 415, the gap is filled by mixing the molten metals of both. However, in the magnetic attachment 400, the circular welding is performed so as to fill the gap with the molten metal in one direction in order, so that the seal ring 415 is pulled when the molten metal cools, so that the welded portion contracts and the unwelded portion is removed. It was found that there was a problem that the gap was enlarged and the sealing disk 414 was greatly inclined. If the sealing disk 414 is tilted during the circular welding, the gap between the sealing disk 414 and the cup-shaped yoke 401 is not only enlarged, but the unwelded portion rises, and a step is generated between the two. As a result, a weld is formed in which the range and depth of melting are not fixed. As a result, the bonding strength is weakened, the sealing property is insufficient, and the production yield is reduced. [0004] Japanese Patent Laying-Open No. 11-137576 discloses a denture attachment having a structure shown in FIG. The denture attachment 500 shown in FIG. 26 is fitted into the opening of the cup-shaped yoke 501 so as to enclose the magnet 502, a soft magnetic cup-shaped yoke 501 having a recess for accommodating the magnet 502, and the magnet 502. The seal plate 513 is composed of a soft magnetic plate yoke 514 and a non-magnetic seal ring 515 clad around the outer periphery thereof. The plate yoke 514, the non-magnetic seal ring 515, and the cup-shaped yoke At least the surface side is welded integrally with 501.

[0005] In the magnetic attachment 500 shown in FIG. 26, the seal plate 503 is press-fitted into the opening of the cup-shaped yoke 501, and there is no possibility that the seal plate 503 is inclined during the circular welding. When assembling the attachment 500, it is difficult to completely press the plate-shaped yoke 504 horizontally into the opening of the cup-shaped yoke 501, and usually, the pressed-in plate-shaped yoke 504 is slightly inclined and cup-shaped. It will be welded to the yoke 501. As a result, there arises a problem that a weld is formed in which the range and depth of melting are not constant. In addition, the operation of press-fitting the small plate-shaped yoke 504 into the small cup-shaped yoke 501 also requires precise control, which is difficult and difficult to automate, resulting in low productivity. Disclosure of the invention

Problems to be solved by the invention

[0006] Accordingly, an object of the present invention is to provide a denture attachment in which the recess of the cup-shaped yoke is sealed with excellent welding quality, has high magnetic attraction, and has good corrosion resistance.

[0007] Another object of the present invention is to provide a method for producing a strong denture attachment with a high production yield.

Means for solving the problem

[0008] The denture attachment according to one embodiment of the present invention includes a permanent magnet, a cup-shaped yoke made of a corrosion-resistant soft magnetic material having a recess for accommodating the permanent magnet, and an opening in the recess of the cup-shaped yoke. A sealing yoke which is fitted therein, wherein said sealing yoke has a plate-like yoke made of a corrosion-resistant soft magnetic material, and a seal ring which is provided on the outer periphery of said plate-like yoke and has a strong corrosion-resistant non-magnetic material. A plurality of spot-welded portions for fixing at least butted portions of the cup-shaped yoke and the seal ring; The sealing plate is joined to the cup-shaped yoke by at least one full-circumferential weld formed so as to cover the butted portion of the sealing ring and the butted portion of the seal ring and the plate-shaped yoke. It is characterized by being sealed.

[0009] Preferably, the magnetic attachment according to the embodiment of the present invention includes a cup-shaped yoke made of a corrosion-resistant soft magnetic material having a permanent magnet, a recess for storing the permanent magnet, and having an enlarged diameter near an open end. A sealing plate fitted to the enlarged diameter portion of the cup-shaped yoke, the sealing plate comprising a plate-shaped yoke made of a corrosion-resistant soft magnetic material, and a corrosion-resistant non-magnetic material provided on the outer periphery of the plate-shaped yoke A plurality of spot welds for fixing at least the enlarged portion of the cup-shaped yoke and the abutting portion of the seal ring; the enlarged portion of the cup-shaped yoke; The seal plate is formed by at least one full-peripheral weld formed to cover the butted portion of the seal ring and the butted portion of the seal ring and the plate-shaped yoke. Serial joined to the cup-shaped yoke, with in the permanent magnet in a state in which a magnetic gap between the permanent magnet and the enlarged diameter portion is sealed. Practically, the step between the enlarged diameter portion and the concave portion is preferably 20 to 200 m.

[0010] A denture attachment according to another embodiment of the present invention includes a permanent magnet, a cup-shaped yoke made of a corrosion-resistant soft magnetic material having a recess for accommodating the permanent magnet, and an opening in the recess of the cup-shaped workpiece. A seal yoke made of a corrosion-resistant soft magnetic material, and a seal ring disposed on the outer periphery of the plate-like yoke and also having a corrosion-resistant non-magnetic material. The seal plate is attached to the cup-shaped yoke by at least one full-circle welded portion formed so as to cover at least the butted portion of the cup-shaped yoke and the seal ring and the butted portion of the seal ring and the plate-shaped yoke. The permanent magnet is sealed and the area near the opening end of the cup-shaped yoke is reduced without substantially changing its width. And characterized in that it.

[0011] A magnetic attachment according to still another embodiment of the present invention includes a cup-shaped yoke made of a corrosion-resistant soft magnetic material having a permanent magnet, a concave portion having an enlarged diameter near an open end for accommodating the permanent magnet, A sealing plate fitted into the enlarged diameter portion of the cup-shaped yoke, wherein the sealing plate is a plate-shaped yoke made of a corrosion-resistant soft magnetic material; A seal ring made of a corrosion-resistant non-magnetic material, which is disposed on the outer periphery; and a butt portion between the enlarged diameter portion of the cup-shaped yoke and the seal ring and a butt portion between the seal ring and the plate-like yoke. The seal plate is joined to the cup-shaped yoke by at least one full-circumferential weld formed so as to cover, so that a magnetic gap is provided between the enlarged diameter portion and the permanent magnet. The permanent magnet is sealed, and the diameter of the region near the opening end of the cup-shaped yoke is reduced without substantially changing its width. For practical purposes, the step between the enlarged diameter portion and the concave portion is preferably 20 to 200 m.

[0012] The spot welded portion may be (a) a butt portion between the cup-shaped yoke and the seal ring, or (b) a butt portion between the cup-shaped yoke and the seal ring, and the seal ring and the plate-shaped yoke. Is preferably formed on both the butted portions. Preferably, the spot welds are substantially equally spaced.

[0013] The full-circumferential welded portion includes: (a) a first welded portion formed so as to cover a butt portion between the cup-shaped yoke and the seal ring over the entire perimeter; Or (b) a butted portion of the cup-shaped yoke and the seal ring, the seal ring, and the plate. It is preferably an integral weld covering the butted portion of the yoke over the entire circumference.

[0014] It is preferable that the surfaces of the seal plate and the cup-shaped yoke are flat-plated after the entire circumference is welded.

[0015] In the method for manufacturing a denture attachment of the present invention, a permanent magnet is housed in a recess of a cup-shaped yoke that also has a corrosion-resistant soft magnetic material, and is disposed on a plate-shaped yoke of the corrosion-resistant soft magnetic material and its outer periphery. A seal plate comprising a seal ring made of a corrosion-resistant non-magnetic material is fitted into the opening of the cup-shaped yoke, and at least a butt portion of the cup-shaped yoke and the seal ring is spot-welded at a plurality of places to form the cup-shaped yoke. The cup-shaped yoke and the seal plate are welded all around so as to cover the butted portion of the seal ring and the butted portion of the seal ring and the plate-shaped yoke.

(A) a force for fixing only the butted portion of the cup-shaped yoke and the seal ring, (b) It is preferable that the spot welding is performed at a plurality of locations so that the butted portion of the cup-shaped yoke and the seal ring and the butted portion of the seal ring and the plate-shaped yoke are fixed at a time.

(A) A first welded portion covering the butted portion of the cup-shaped yoke and the seal ring over the entire circumference, and a first welded portion covering the butted portion of the seal ring and the plate-shaped yoke over the entire circumference. Or (b) integrally covering the butted portion between the cup-shaped yoke and the seal ring and the butted portion between the seal ring and the plate-shaped yoke. As described above, it is preferable to perform the full circumference welding.

[0018] After the entire circumference welding, it is preferable that the seal plate and the cup-shaped yoke are processed in a plane.

The invention's effect

According to the present invention, since the seal plate is loosely fitted into the opening of the concave portion of the cup-shaped yoke, and the seal plate and the cup-shaped yoke are temporarily fixed by spot welding and then the entire circumference is welded. The plate is welded almost parallel to the surface of the cup-shaped yoke without tilting, and the welded portion of the cup-shaped yoke and the seal plate has a substantially uniform shape, melting amount and melting depth over the entire circumference. And stable quality. Therefore, there is no possibility that the welded portion becomes locally shallow or a through hole is formed after the welding surface is flattened, and the sealing performance is not deteriorated. Therefore, the denture attachment of the present invention has a reduced diameter in the area near the opening end of the cup-shaped yoke, has high magnetic attraction, has good corrosion resistance, is durable, is inexpensive, and can be reduced in size and thickness. Can be.

Brief Description of Drawings

FIG. 1 (a) is a plan view showing a denture attachment according to a first embodiment of the present invention.

FIG. 1 (b) is a cross-sectional view showing a state before welding the entire circumference of the denture attachment of FIG. 1 (a).

FIG. 1 (c) is a cross-sectional view showing a state of the denture attachment of FIG. 1 (a) after full-circumference welding.

FIG. 1 (d) is a cross-sectional view taken along the line A-0-A of FIG. 1 (a) (showing a state of the denture attachment of Example 1 after planar processing).

FIG. 2 is a schematic view showing a step of manufacturing the denture attachment of FIG. 1 (a) (each figure on the right shows a section taken along line A-0-A of the figure on the left). FIG. 3 (a) is a plan view showing a welding surface of the denture attachment of FIG. 1 (a) before planar processing.

FIG. 3 (b) is a sectional view taken along line A-0-A in FIG. 3 (a).

FIG. 4 (a)] is a plan view showing a denture attachment according to a second embodiment of the present invention.

FIG. 4 (b) is a sectional view taken along line B-0-B of FIG. 4 (a).

圆 5] is a schematic view showing a step of manufacturing the denture attachment of FIG. 4 (a) (each figure on the right shows a cross section B-0-B in the figure on the left).

FIG. 6 (a)] is a plan view showing a denture attachment according to a third embodiment of the present invention.

FIG. 6 (b) is a sectional view taken along line C-0-C of FIG. 6 (a).

[7] FIG. 6 (a) is a schematic view showing a step of manufacturing the denture attachment of FIG. 6 (a) (each figure on the right shows a cross section C-0-C of the figure on the left).

FIG. 8 (a)] is a plan view showing a denture attachment according to a fourth embodiment of the present invention.

FIG. 8 (b) is a sectional view taken along the line D-0-D of FIG. 8 (a).

FIG. 9 (a)] is a plan view showing a denture attachment according to a fifth embodiment of the present invention.

FIG. 9 (b) is a sectional view taken along line E-0-E of FIG. 9 (a).

[10] Fig. 10 is a sectional view showing a denture attachment according to a sixth embodiment of the present invention. FIG. 11 (a) is a photograph partially showing a cross section of the vicinity of a left welded portion of a denture attachment according to a seventh embodiment of the present invention after a flat surface processing.

FIG. 11 (b)] is a photograph partially showing a cross section of the vicinity of the right welded portion of the denture attachment of FIG. 11 (a) after flattening.

FIG. 12 (a) is a diagram corresponding to FIG. 11 (a).

FIG. 12 (b) is a diagram corresponding to FIG. 11 (b).

FIG. 12 (c) is a cross-sectional view showing the entire structure of the denture attachment of FIG. 11 (a) after plane machining.

FIG. 13 (a) is a photograph partially showing an as-welded cross section near the left welded part of the denture attachment of Example 3.

FIG. 13 (b) is a photograph partially showing an as-welded cross section near the right welded portion of the denture attachment of Example 3. FIG. 14 (a) is a diagram corresponding to FIG. 13 (a).

FIG. 14 (b) is a diagram corresponding to FIG. 13 (b).

FIG. 14 (c) is a cross-sectional view showing the entire structure of the denture attachment of FIG. 13 (a) in an as-welded state.

FIG. 15 is a schematic sectional view showing the inclination of the seal plate when the cup-shaped yoke and the seal plate are welded all around without a spot weld.

FIG. 16 is a partial cross-sectional perspective view showing a denture attachment obtained by pressing a seal plate into an opening of a cup-shaped yoke and then welding the cup-shaped yoke and the seal plate all around.

FIG. 17 is a plan view showing one sample of a denture attachment of Comparative Example 3.

FIG. 18 is a plan view showing another sample of the denture attachment of Comparative Example 3.

FIG. 19 is an enlarged view of a region A in FIG. 18.

FIG. 20 is a micrograph corresponding to FIG.

FIG. 21 is a micrograph showing a fitting portion of a seal plate of a denture attachment of Comparative Example 5.

FIG. 22 is a schematic diagram corresponding to the micrograph of FIG. 21.

FIG. 23 is a schematic view showing an apparatus for measuring a magnetic attraction force of a denture attachment.

FIG. 24 is a schematic cross-sectional view showing a state in which a denture having a denture attachment is mounted on a keeper installed on a root plate embedded in an alveolar cavity.

FIG. 25 is a schematic sectional view showing a conventional denture attachment.

FIG. 26 is a schematic sectional view showing a conventional denture attachment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] The denture attachment of the present invention will be described in detail below with reference to the accompanying drawings. However, since a part having the same reference numeral in the first digit is basically common to each embodiment, first, Only the description of the first embodiment will be given, and detailed description will be omitted in the following embodiments.

FIGS. 1 and 2 show a denture attachment according to a first embodiment of the present invention. This denture attachment has the same basic structure as that shown in FIG. 25, and has a cup-shaped yoke 1 having a circular cross section formed with a soft magnetic material, also having a permanent magnet 2 housed therein, and an opening of a recess 1 ′. It consists of a seal plate 3 fitted in the mouth. Seal plate 3 seals permanent magnet 2 in recess 1 '. And a member forming a magnetic circuit, and is composed of a circular plate-shaped yoke 4 made of a soft magnetic material and a seal ring 5 made of a non-magnetic material having the same width and mounted on the outer periphery thereof. Have been. The outer shapes of the cup-shaped yoke 1 and the seal plate 3 are not limited to circular shapes, but may be elliptical shapes or polygonal shapes such as squares.

In the present invention, it is preferable to use corrosion-resistant soft magnetic stainless steel (for example, SUS447J1, SUSXM27, SUS444, etc.) for the cup-shaped yoke and the plate-shaped yoke. Further, it is preferable to use a corrosion-resistant non-magnetic stainless steel (for example, SUS316L) for the seal ring.

[0024] In order to increase the assembling efficiency of the denture attachment, the sealing plate 3 is formed by fitting a cylindrical member of a non-magnetic material to be a seal ring 5 to a round bar of a soft magnetic material to be a plate-shaped yoke 4, and performing drawing. It is preferable to form the resulting material by slicing it to a predetermined thickness. The seal plate obtained by slicing is heat-treated in a reducing atmosphere at 600-880 ° C for 0.5-10 hours, preferably at 700-850 ° C for 18 hours, and cooled to room temperature. If the heat treatment condition is less than 600 ° C for 0.5 hour, no bonding occurs between the plate yoke 4 and the seal ring 5, and if the heat treatment exceeds 880 ° C for 0.5 hour, the interface between the plate yoke 4 and the seal ring 5 The denture attachment obtained by fusion and as shown in Comparative Example 3 described below has a low magnetic attraction force. The heat treatment weakly (lightly) joins the disc to be the plate yoke 4 and the cylindrical material to be the seal ring 5. The term “weak (light) joint” means that the area ratio of the fusion zone at the joint interface between the disk and the cylinder is less than 10%, especially less than 5%. The heat treatment under the above conditions may be performed before slicing.

[0025] Since the seal plate 3 and the cup-shaped yoke 1 are manufactured separately, the fitting dimensions inevitably vary. Therefore, instead of press-fitting the seal plate 3 into the cup-shaped yoke 1 as in the conventional denture attachment, if the outer diameter of the seal plate 3 is set slightly smaller than the inner diameter of the cup-shaped yoke 1, the seal plate 3 is moved to the cup-shaped yoke. This is preferable because it can be easily fitted into the opening. The gap X between the sealing plate 3 and the cup-shaped yoke 1 is preferably set to 10 to 60 m in order to ensure sealing by welding. As shown in FIG. 1B, the gap X is (the inner diameter of the cup-shaped yoke 1) − (the outer diameter of the sealing plate 3).

As shown in FIG. 1B, the seal plate 3 is fitted into the recess 1 ′ so as to be in close contact with the upper surface of the permanent magnet 2 housed in the recess 1 ′ of the cup-shaped yoke 1. At this time, the top of the seal plate 3 It almost coincides with the upper surface of the yoke 1. The sealing plate 3 and the cup-shaped yoke 1 are welded by a laser or an electron beam, and the permanent magnet 2 inside is sealed in the yoke and sealed from the outside. The welded portion is a spot welded portion 6 provided at a plurality of locations so as to cover the butted portion of the seal plate 3 and the cup-shaped yoke 1, the butted portion of the cup-shaped yoke 1 and the seal ring 5, and the seal ring 5 and the plate-shaped yoke. 4 and the entire circumference weld 7 formed to cover the butted portion.

[0027] The spot welded portion 6 is a portion that has been melt-solidified (welded) by irradiating a laser beam in a spot manner. At this time, the laser light may be moved if it is slight. In the first embodiment, the laser spot diameter covers a part of the cup-shaped yoke 1 and the plate-shaped yoke 4 sandwiching the seal ring 5. Therefore, the plate-shaped yoke 4 is integrally fixed to the cup-shaped yoke 1 by the spot welds 6. However, this is not an essential requirement.When the seal ring 5 and the plate-shaped yoke 4 are firmly fixed by drawing, at least the butted portion of the cup-shaped yoke 1 and the seal ring 5 is fixed by the spot weld 6. It would be fine. It is preferable that the spot welds 6 are provided at a plurality of locations (eg, 2 to 8 locations) at substantially equal intervals (symmetrically with respect to the point) with respect to the center axis of the seal plate 3. In the illustrated example, the spot welds 6 include four spot welds 6a-6d.

In the present embodiment, as shown in FIG. 1 (c), the entire circumference welded portion 7 is formed by a butt portion between the cup-shaped yoke 1 and the seal ring 5, and a butt portion between the seal ring 5 and the plate-shaped yoke 4. Is integrally formed over the entire circumference. The integral perimeter weld 7 is suitable when the width of the seal ring 5 is narrow, for example, 1Z2 or less of the spot diameter. The integrated all-circumferential welded portion 7 is formed by simultaneously irradiating the cup-shaped yoke 1 and the plate-shaped yoke 4 with laser light with the seal ring 5 interposed therebetween.

[0029] The cup-shaped yoke 1 has the same width w from near the bottom surface of the concave portion 1 'to near the open end. In the denture attachment after full circumference welding shown in Fig. 1 (c), the outer diameter Dou 'near the opening end of the recess 1' is smaller than the outer diameter Dob near the bottom of the recess 1 'of the cup-shaped yoke 1. ! / Ru (Dob> Dou '). As shown in Fig. 1 (d), the outer diameter Dou becomes Dou after plane processing.

[0030] The phenomenon that the outer diameter near the opening end is reduced is considered to occur for the following reason. When the cup-shaped yoke 1 and the seal ring 5 are fixed by spot welding by spot welding, the outer diameter of the cup-shaped yoke 1 near the opening end of the concave portion has not been reduced. This is because spot welds 6a-6d At the time of solidification after melting, a force for shrinking is generated in the welded portion. However, since the volume of the spot welded portions 6a-6d is small, the cup-shaped yoke 1 cannot be pulled. When all-around welding is started, the melted butted portion (welded portion) solidifies and shrinks, so that a force acts to pull the gap-shaped yoke 1 and the seal ring 5 toward the welded portion. At this time, since the seal ring 5 is melted and fixed to the side of the cup-shaped yoke 1 via the spot welded portion, the seal ring 5 does not deform even when pulled by the welded portion. On the other hand, since the outer periphery of the cup-shaped yoke 1 is not fixed, the cup-shaped yoke 1 is pulled by the welded portion and gradually deforms. As the laser irradiation position is shifted in the circumferential direction and the entire circumference is welded, the vicinity of the opening end of the cup-shaped yoke 1 is gradually pulled toward the welded side, and almost uniformly when the entire circumference is welded. To shrink If the entire circumference is welded without temporary fixing by spot welding, the unfixed seal ring will be strongly attracted to the weld and the seal plate will rise greatly.

[0031] As shown in FIG. 1 (d), the welding surface of the seal plate 3 and the cup-shaped yoke 1 is flattened by polishing or the like. By the planar processing, the local unevenness of the welded portion is removed, and a smooth surface 9 is formed. Since the smooth surface 9 of the denture attachment is in good contact with the root plate embedded in the alveolar cavity, there is no magnetic flux disturbance. As a result, the denture fitted with the denture attachment of the present invention is firmly held in the alveolar cavity.

FIG. 2 shows a manufacturing process of the denture attachment of FIG. 1 (a). First, the permanent magnet 2 is housed in the recess 1 ′ having a circular cross section of the soft magnetic cup-shaped yoke 1, and the seal plate 3 is fitted into the opening of the recess 1 ′. The tip of the inclined holding member 3a is placed almost at the center of the seal plate 3, and the seal plate 3 is fixed [step (a)]. In this state, spot welding at a plurality of locations 6a → 6b → 6c → 6d is performed so as to cover the butted portion la of the cup-shaped yoke 1 and the seal ring 5 and the butted portion 4a of the seal ring 5 and the plate-shaped yoke 4. [Step (b)] is performed in order. By performing spot welding in the order of the diagonal points 6a → 6b → 6c → 6d using the laser irradiation device 3b in this manner, the shrinkage force applied to the seal plate 3 when the molten metal is cooled and solidified is reduced and The balance can be achieved, and the floating of the seal plate 3 as in the prior art can be prevented. The seal plate 3 is firmly fixed to the cup-shaped yoke 1 by the obtained spot welds 6a to 6d.

[0033] As the seal plate 3, after the plate yoke 4 and the seal ring 5 are integrally formed by drawing, the heat treatment is performed. In the case of using a material obtained by fusing the joints by a process or the like, spot welding may be performed only on the butted portion la of the seal ring 5 and the cup-shaped yoke 1.

After removing the pressing member 3a [Step (c)], the spot diameter covering the butted portion la of the cup-shaped yoke 1 and the seal ring 5 and the butted portion 4a of the seal ring 5 and the plate-shaped yoke 4 The laser beam is continuously or intermittently irradiated to form the entire circumferential weld 7 [step (d)]. Since the seal plates 3 are fixed to the cup-shaped yoke 1 at substantially equal intervals, a uniform full-circle weld 7 can be obtained under stable welding conditions such that the seal plates 3 do not shift during full-circle welding. The opening of the cup-shaped yoke 1 is completely sealed, and the external force of the permanent magnet 2 is also hermetically shut off by a weld bead with a substantially uniform shape, melting amount and melting depth over the entire circumference. You. It is preferable that the laser beam for all-around welding has the same spot diameter as the laser beam for spot welding. FIG. 3 (a) shows the surface condition of the cup-shaped yoke 1 and the seal plate 3 after the entire circumference welding, and FIG. 3 (b) shows the cross-section. In this example, the spot welds 6a to 6d are concealed by the entire circumference weld 7 but the spot denoted by reference numeral 7 'is the end of the full circumference weld.

[0035] The cup-shaped yoke 1 on which welding has been completed is set on a plane polishing machine, and the welded surfaces of the cup-shaped yoke 1 and the seal plate 3 are flat-worked (polished) to a predetermined depth δ (step (e)). . The depth of cut δ is about 10 _i um—about 100 _i um, preferably 40 _i um—, so that the cup-shaped yoke 1 and the seal plate 3 are at the same height and the unevenness of the entire weld 7 is not left. It should be 60 _i um. If δ is less than 10 μm, irregularities remain on the surface. On the other hand, if δ exceeds 100 / zm, the volume of the welded portion becomes too small, and the weld strength decreases. Since the sealing plate 3 is welded almost parallel to the cup-shaped yoke 1 without tilting, the shape of the molten portion, the amount of fusion and the depth of fusion are substantially uniform over the entire circumference even after the flat surface processing, and the molten portion is There is no reduction in sealing performance due to local shallowness or through holes.

[0036] In order to stabilize the non-magnetic phase (austenite phase) of the welded portion and to recover the magnetic force degraded by the mechanical strain of the permanent magnet incorporated in the magnetic attachment, heat treatment is performed after the planar processing. Is preferred. This heat treatment is preferably performed in an inert gas atmosphere at a temperature of 600 to 1100 ° C for 0.5 to 10 hours, preferably 700 to 900 ° C for 5 hours, and then cooled to room temperature. If the heat treatment conditions are less than 0.5 hours at 600 ° C X, the effect of the heat treatment is not sufficient. The force is greatly reduced, and the thermal deformation of the cup-shaped yoke and the seal plate cannot be ignored. Finally, it is magnetized to obtain the denture attachment of the present invention.

As shown in FIG. 1 (c), after welding the entire circumference due to the gap X between the cup-shaped yoke 1 and the seal plate 3, the cup-shaped yoke 1 is slightly deformed inward. Since the sealing plate 3 is fixed to the cup-shaped yoke 1 by spot welding and the entire circumference is welded, deformation occurs almost uniformly in the circumferential direction. This deformation z ′ is almost half of the gap X. This is because the amount of inward deformation of the cup-shaped yoke 1 is z ′ at both ends in the diametrical direction, and is 2 ° ′ as a whole. For example, when the seal plate 3 is thinned by about 20% by the flat processing, the deformation amount の after the flat processing is about 80% of ζ ′. In general, the deformation ζ is about 10-40 m.

FIGS. 4 (a) and 4 (b) show a denture attachment according to the second embodiment of the present invention, and FIG. 5 shows a manufacturing process thereof. In this embodiment, spot welds 26e, 26g, 26i, 26k covering the first butted portion 21a of the cup-shaped yoke 21 and the seal ring 25, and the second butted portion 24a of the seal ring 25 and the plate-shaped yoke 24 Spot welds 26f, 26h, 26j, 261 that cover the first and second full-circle welds 27a and 27b, respectively, on the first butt 21a and the second butt 24a. To form Adjacent spot welds 26e and 26f, 26g and 26h, 26i and 26j, and 26k and 261 do not overlap, nor does the first full circumference weld 27a and the second full circumference weld 27b. . Since the non-magnetic seal ring 25 is exposed between the first full circumference weld 27a and the second full circumference weld 27b, a short circuit of magnetic flux between the cup-shaped yoke 21 and the plate-shaped yoke 24 can be prevented. It can be effectively prevented.

The method of manufacturing the denture attachment of the second embodiment is the same as that of the first embodiment, except that the spot welds 26e-261 and the entire circumferential welds 27a and 27b are individually formed.

FIGS. 6 (a) and 6 (b) show a denture attachment according to a third embodiment of the present invention, and FIG. 7 shows a manufacturing process thereof. The denture attachment of this embodiment includes a spot welded portion 36e, 36g, 36i, 36k covering the first butted portion 31a of the cup-shaped yoke 31 and the seal ring 35, and a second butted portion of the seal ring 35 and the plate-shaped yoke 34. The first and second full-circle welds 37a, 36h, 36j, and 361 respectively cover the first and third full-circle welds 37a and 34a. Force similar to that of the second embodiment in that it has a portion 37b Adjacent spot welds 36e and 36f, 36g and 36h , 36i and 36j, and 36k and 361 overlap with each other, and the first full circumference weld 37a and the second full circumference weld 37b also overlap with those of the second embodiment. For example, reference numeral 36m is a portion where the spot welds 36k and 361 overlap, and reference numeral 37c is a portion where the first full circumference weld 37a and the second full circumference weld 37b overlap. As shown by the dotted line in FIG. 6 (a), the overlapping portion between the first full-circumferential welded portion 37a and the second full-perimeter welded portion 37b is located at the substantially central portion of the seal ring 35. Since the soft magnetic material of the plate-like yoke 34 is hardly mixed, there is no particular problem in the magnetic circuit. Moreover, the above-mentioned overlapping part is almost removed by plane processing.

FIGS. 8 (a) and 8 (b) show a denture attachment according to a fourth embodiment of the present invention. The denture attachment of this embodiment includes a spot welded portion 46a-46d that covers the first butted portion of the cup-shaped yoke 41 and the seal ring 45 and the second butted portion of the seal ring 45 and the plate-shaped yoke 44. In addition, the first butting portion and the second butting portion each have a first full circumference welded portion 47a and a second full circumference welded portion 47b. The spot welds 46a-46d are formed in the same manner as in the first embodiment, and the first full circumference weld 47a and the second full circumference weld 47b are formed in the same manner as the third embodiment.

FIGS. 9 (a) and 9 (b) show a denture attachment according to a fifth embodiment of the present invention. The denture attachment of this embodiment is the same as that of the first embodiment except that a Ni plating layer 54b is provided between the plate-like yoke 54 of the seal plate 53 and the seal ring 55. If the Ni plating layer 54b has a thickness of, for example, 15 m, the radius of the seal plate 53 is reduced accordingly. When the Ni plating layer 54b is melt-mixed with the soft magnetic material of the seal plate 53, it changes into a non-magnetic alloy, so that leakage of magnetic flux between the plate yoke 54 and the cup yoke 51 can be effectively prevented. .

FIG. 10 shows a denture attachment according to a sixth embodiment of the present invention. The denture attachment of this embodiment has a cup-shaped yoke 61 having an enlarged diameter portion 61c. Other points are the same as those of the denture attachment of the second embodiment. In order to function as a magnetic gap that effectively prevents the leakage of magnetic flux between the plate-shaped yoke 64 and the cup-shaped yoke 61, the radial depth (w-w) of the enlarged diameter portion 61c is about 20-200 μm. It is preferred that

1

The height h (distance between the upper end surface of the cup-shaped yoke 61 and the lower end of the step 61d) of the enlarged diameter portion 61c is It is preferably about 200 to 400 m. It is preferable that the inclination angle (the angle with the horizontal line) of the step 61d is 0-60 °. In the magnetic attachment shown in FIG. 10, the outer appearance is characterized in that the area near the opening end of the concave portion 61c is smaller in diameter than the outer diameter near the bottom of the enlarged diameter portion 61c of the cup-shaped yoke 61.

In this embodiment, the inner end of the seal ring 65 is preferably located inside the side surface of the permanent magnet 62 in order to effectively prevent the leakage of magnetic flux. Therefore, the thickness of the seal ring 65 is preferably about 40 to 400 μm.

[0045] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In each of the examples and comparative examples, the cup-shaped yoke and the disk-shaped yoke were formed of corrosion-resistant soft magnetic stainless steel SUS447J1 (saturated magnetization Bs: 1.28 T), and the seal ring was formed of corrosion-resistant nonmagnetic stainless steel SUS316L. The disk-shaped permanent magnet is made of Nd-Fe-B anisotropic sintered magnet (NEOMAX NMX-48CH, residual magnetic flux density Br: 1.35 T, maximum energy product (BH) max: 366 kj / m ³ ) Formed. The dimensions of the permanent magnet were 2.55 mm in outer diameter and 0.4 mm in height.

[0046] Decoration II

Cup-shaped yokes and seal plates of the sizes shown in Table 1 were used. This seal plate is made by fitting a cylindrical material to be a seal ring to a round bar for a disk-shaped yoke, slicing it to a thickness of 0.2 mm, heat-treating it at 800 ° C in a reducing atmosphere, It has been cooled down. The obtained seal plate had a weakly joined shield ring on the outer periphery of the disk-shaped yoke. Assemble as shown in Fig. 1 (b), and as shown in Table 2, 0.5 mm of equiangular intervals of 90 ° along a 2.4 mm diameter circumference (centered at point 0 in Fig. Temporary fixation was performed by spot welding using a laser beam with a spot diameter, and then welding was performed with a laser beam with a spot diameter of 0.5 mm along the same circumference of 2.4 mm diameter [Fig. L (c)]. As shown in FIG. 3 (b), the opening of the cup-shaped yoke 1 immediately after the welding was reduced by z ′. This is because the region near the opening end of the cup-shaped yoke 1 was deformed in a direction to fill the gap X between the cup-shaped yoke 1 and the seal plate 3. Finally, the lap was polished to a depth δ of 0.05 mm, and the weld surface was finished so as to have a maximum surface roughness Rmax force l / zm or less, and the denture attachment shown in FIGS. 1 (a) and (d) was produced. The depth of the weld after flattening was uniform at 0.1 mm. After plane polishing 800 Heat treatment was performed for 1 hour in an argon atmosphere at ° C. The reduction in the outside diameter of the opening of the cup-shaped yoke 1 was reduced to z (value in Table 3) after surface polishing [Figure l (d)]. As shown in Fig. 1 (d), the magnetic attachment was magnetized after planar polishing.

[0047] Regarding the obtained denture attachment, the presence or absence of burrs between the cup-shaped yoke 1 and the seal ring 5, the variation and reduction z of the outer diameter of the cup-shaped yoke 1, the rising amount t of the sealing plate 3, and the magnetic field The suction force was measured. Table 3 shows the measurement results.

The apparatus shown in FIG. 23 was used for measuring the magnetic attractive force. This measuring device supports a chuck 93 for fixing a denture attachment 90, a digital force gauge 95 connected to the chuck 93 via an adapter 94, a fine movement device 96 for moving the digital force gauge 95, and a fine movement device 96. The stand includes a stand 97 and a support member 92 fixed to the stand 97 so as to support the keeper 91. With the denture attachment 90 fixed to the chuck 93 and the keeper 91 fixed to the support member 92 attracted, the fine movement device 96 is gradually raised, and the digital force gauge when the denture attachment 90 is separated by the keeper 91 force. A value of 95 was read. The magnetic attraction force was measured for ten denture attachments 90, and the average of the obtained values was defined as the magnetic attraction force.

[0049] Decoration 12— 6

A cup-shaped yoke and a seal plate having the sizes shown in Table 1 (the seal plate had a misalignment in which the shield ring was weakly joined to the outer periphery of the disk-shaped yoke as in Example 1) were used. Assemble as shown in Fig. 5, and as shown in Table 2, a circumference of 2.6 mm in diameter covering the butted portion of cup-shaped yoke 21 and seal ring 25 (centering on point 0 in Fig. 5 (a)). The first spot welding is performed by laser beam with a spot diameter of 0.2 mm at 90 ° equiangular intervals along with), and a circle with a diameter of 2.2 mm covers the butted portion of the seal ring 25 and the plate-shaped yoke 24. A second spot welding is performed along the circumference (centered at point 0 in Fig. 5 (a)) with laser light having a spot diameter of 0.2 mm at equiangular intervals of 90 °. Temporarily fixed to 21. Next, along with the circumference of 2.6 mm in diameter, which is the same as the circumference of the first spot welding, the first full circumference welding is performed using a laser beam with a spot diameter of 0.2 mm, and the same diameter as the circumference of the second spot welding. A second full circumference weld was performed using a laser beam with a spot diameter of 0.2 mm along the circumference of 2.2 mm [Fig. 5 (d)]. Finally, the weld surface is flattened by polishing to a depth δ of 0.05 mm. The denture attachment shown in FIGS. 4 (a) and 4 (b) was produced. Regarding the obtained denture attachment, in the same manner as in Example 1, the presence or absence of burrs between the cup-shaped yoke 21 and the seal ring 25, the variation in the outer diameter of the cup-shaped yoke 21 and the amount of reduction z, the sealing plate 23 The lifting amount t of the sample and the magnetic attraction force were measured. Table 3 shows the measurement results.

Example 7

As shown in Table 2, a denture attachment shown in FIG. 6 was produced in the same manner as in Example 2 except that the spot diameter of the laser beam for spot welding and the laser beam for all-around welding were each 0.3 mm, and the characteristics were measured. Table 3 shows the measurement results.

Example 8

As shown in Table 2, a denture attachment shown in FIG. 8 was prepared and the characteristics were measured in the same manner as in Example 1 except that the entire circumference was welded in the same manner as in Example 7. Table 3 shows the measurement results.

[0052] Decoration 19

A denture attachment shown in FIG. 9 was produced in the same manner as in Example 1 except that a Ni plating layer having a thickness of 15 μm was provided between the plate-shaped yoke and the seal ring, and the characteristics were measured. Table 3 shows the measurement results.

Example 10—14

As shown in Table 1, a denture attachment shown in FIG. 10 was produced in the same manner as in Example 26 except that a cup-shaped yoke having a step 61d in the concave portion 61 ′ was used. Micrographs of the cross section of the weld are shown in Figs. 11 (a) and (b). As is apparent from FIGS. 12 (a) and (b) corresponding to the micrographs of FIGS. 11 (a) and (b), the outer surface near the opening end of the concave portion of the cup-shaped yoke 71 has a perpendicular UU (the perpendicular UU is permanent). Parallel to the leftmost or rightmost contour line VV of the magnet 72; inclined slightly inward with respect to;) (straight line TT). The distance 垂 between the perpendicular U-U and the straight line Τ-Τ on the straight line S-S passing through the surface of the denture attachment ζ represents the decrease in the outer diameter of the cup-shaped yoke 71. Table 3 shows the measurement results of the characteristics of each denture attachment.

From FIG. 12 (c), the outer diameter Dou at the opening end of the recess (position Q) is smaller than the outer diameter Dob near the bottom (position Ρ) of the enlarged diameter portion of the recess of the cup-shaped yoke 71. (Dob> Dou). The width w of the cup-shaped yoke 71 did not change until the force near the bottom of the enlarged diameter portion (position P) reached the open end of the concave portion (position Q). Example 15

As shown in Table 2, a denture attachment was produced in the same manner as in Example 10 except that the spot diameter of the laser beam for spot welding and the laser beam for all-around welding were each set to 0.3 mm. Micrographs of the cross section of the weld are shown in Figs. 13 (a) and (b). FIGS. 14 (a) and (b) are diagrams corresponding to the micrographs of FIGS. 13 (a) and (b), and FIG. 14 (c) shows a cross-sectional shape of the entire denture attachment. Table 3 shows the measurement results of the characteristics of the denture attachment.

Comparative Example 1

As shown in Tables 1 and 2, using the same cup-shaped yoke and seal plate as in Example 1 (the gap between the two was 30 / zm), the same entire circumference welding as in Example 1 was performed without spot welding. However, as shown in FIG. 15, the seal plate 103 was completely lifted up on the beam of the cup-shaped yoke 10, and a force was not able to complete the entire circumference welding (see Table 3).

[0057] Comparative Example 2

As shown in Tables 1 and 2, using the same cup-shaped yoke and seal plate as in Example 7 (the gap between them was 30 m), the same perimeter welding as in Example 7 was performed without spot welding. However, the seal plate completely lifted above the cup-shaped yoke, and the entire circumference welding could not be completed.

Comparative Example 3

As shown in Tables 1 and 2, the denture was prepared in the same manner as in Example 1 except that the outer diameter of the seal plate and the inner diameter of the recess of the cup-shaped yoke were the same, and the seal plate was pressed into the recess of the cup-shaped yoke. Attachments were made. Press-fitting the seal plate was a cumbersome operation. The obtained denture attachment had a burr 201b between the cup-shaped yoke 201 and the seal ring 205, as shown in FIG. 16, and the cup-shaped yoke 201 was slightly deformed outward. Since the direction of the deformation is opposite to that of the denture attachment of the present invention, the amount of deformation z (the radius of the outer periphery 201R-the radius of the outer periphery 201r) is displayed as a minus. 201R indicates the outer circumference after the entire circumference welding, and 201r indicates the outer circumference after the press-fitting and before the welding. Table 3 shows the measurement results of the characteristics of the denture attachment.

As shown in FIG. 16, the outer circumference of the end face of the cup-shaped yoke 201 is moved from 201r by full circumference welding.

201R, the area of the end face of the cup-shaped yoke 201 is S [= S X α (α is a constant, α> 1

R r

)]. Since the magnetic flux generated from the permanent magnet 202 does not change, the cup-shaped yoke The relationship between the area of the end face of 201 and the magnetic flux emitted therefrom is BXS = B 'XS (B and S are the magnetic flux density before the area expansion r R r and the area of the end face, and B' and S are the area after the area expansion. Flux density and edge

R

The area of the surface. ). Therefore, Β '= ΒΖα. Since the magnetic attractive force is proportional to the product of the square of the magnetic flux density and the area through which the magnetic flux passes, the ratio of the magnetic attractive force F 'after expansion to the magnetic attractive force F before expansion is (SX B' ² ) / (S Χ Β ² ) = Β '/ Β = 1 / _α . in this way

R r

When the outer periphery of the cup-shaped yoke 201 is expanded by press fitting, the magnetic attraction force decreases.

On the other hand, in each of the magnetic attachments of the embodiments, the area S (= Sm × BmZBs) of the end surface of the cup-shaped yoke is designed to be optimal (<S <S). Bs is cup r r R

The saturation magnetization of the magnetic field, Bm is the residual magnetic flux density of the permanent magnet, and Sm is the cross-sectional area of the permanent magnet. If the area of the end face of the yoke is smaller than S, the flow of magnetic flux deteriorates (since local magnetic saturation occurs), so that magnetic flux leakage becomes remarkable and the magnetic attraction force is greatly reduced. In the present invention, the design is made to obtain the optimum S when the outer periphery of the cup-shaped yoke is contracted, so that the magnetic attraction force increases. The measurement results of the magnetic attraction force of Comparative Example 5 shown in Table 3 were clearly lower than those of Example 1.

FIG. 17 shows a state in which a gap is formed on one side of the butted portion of the cup-shaped yoke 201 and the seal ring 205 when the seal plate is pressed into the cup-shaped yoke 201. Since the inner diameter of the cup-shaped yoke 201 is equal to the outer diameter of the seal plate, if one end of the outer periphery of the seal plate is inserted into the opening of the cup-shaped yoke 201, the other end of the outer periphery of the seal plate is inevitably connected to the cup. Hooked on the opening edge of the yoke 201. When the sealing plate is pressed into the opening of the cup-shaped yoke 201 in this state, at least one of the cup-shaped yoke 201 and the sealing plate is scraped off at the butted portion, and the glue is formed at the portion of the butted portion having the glue. Creates a gap. In the sample shown in FIG. 17, since the plate-like yoke 204 and the seal ring 205 were firmly fixed, a force was generated at the butted portion without any gap.

FIG. 18 shows a portion where the cup-shaped yoke 301 and the seal ring 305 abut when the seal plate in which the plate-shaped yoke 304 and the seal ring 305 are not firmly fixed is pressed into the cup-shaped yoke 301. And a state in which a gap deviated to one side is generated at the butted portion of the plate-shaped yoke 304 and the seal ring 305. FIG. 19 is an enlarged view of part A of FIG. 18, and FIG. 20 is a micrograph of that part. As is clear from FIGS. 19 and 20, the cup-shaped yoke 301 Glue 305b remained at the butted portion with thread ring 305.

FIG. 21 is a photomicrograph showing the vicinity of the butted portion of the sample in FIG. 20, and FIG. 22 is a schematic view corresponding thereto. Since the seal ring 305 before press-fitting has a rectangular cross-section, it can be seen that the outer end of the seal ring 305 is shaved. Burrs 301b and 305b were observed between the corner of the seal ring 305 and the yoke 301.

[0064] Comparative Example 4

As shown in Tables 1 and 2, the denture attachment was performed in the same manner as in Example 7 except that the outer diameter of the seal plate and the inner diameter of the recess of the cup-shaped yoke were the same, and the seal plate was pressed into the recess of the cup-shaped yoke. Was prepared. Press-fitting the seal plate was a cumbersome operation. Table 3 shows the measurement results of the characteristics of the obtained denture attachment. The measurement results of the magnetic attraction force of Comparative Example 4 shown in Table 3 were clearly lower than those of Example 1.

Comparative Example 5

As shown in Tables 1 and 2, a denture attachment was prepared in the same manner as in Comparative Example 5 except that a 15 μm-thick Ni plating layer was provided between the plate yoke and the seal ring, and the characteristics were measured. Table 3 shows the results. The measurement results of the magnetic attraction force of Comparative Example 5 shown in Table 3 were clearly lower than those of Example 1. Press-fitting of the seal plate was a troublesome operation.

Comparative Example 6

As shown in Tables 13 and 13, a denture attachment was produced in the same manner as in Example 1 except that the gap X between the cup-shaped yoke and the seal plate was set to 70 m, and the characteristics were measured. The measurement results of the magnetic attraction force of Comparative Example 6 shown in Table 3 were clearly lower than those of Example 1. Table 3 shows the results. Press-fitting of the seal plate was a laborious operation. In addition, after polishing the surface, dents due to welding remained, and a smooth surface was not obtained, and the power was not practical.

[0067] [Table 1] Example No. Each part (Dimensions of "(mm)

Cup-shaped yoke Seal plate Outline (>> recess (2) Step Disc-shaped Ni ^<3 >

Yorkshire

ω 1 / Relling ⁽⁴ > Example 1 3.50X1.3 2.60X0.6 None 2.17X0.2 None 2.57X2.17X0.2 Example 2 3.50X1.3 2.60X0.6 None 2.17X0.2 None 2.57X2. 17X0.2 Example 3 3.50X1.3 2.60X0.6 None 2.19X0.2 None 2.59X2.19X0.2 Example 4 3.50X1.3 2.60X0.6 None 2.18X0.2 None 2.58X2.18X0.2 Implementation Example 5 3.50X1.3 2.60X0.6 None 2.16 0.2 None 2.56X2.16X0.2 Example 6 3.50X1.3 2.60X0.6 None 2.15X0.2 None 2.55X2.15X0.2 Example 7 3.50X1.3 2.60X0.6 None 2.17X0.2 None 2.57X2.17X0.2 Example 8 3.50X1.3 2.60X0.6 None 2.17X0.2 None 2.57X2.17X0.2 Example 9 3.50X1.3 2.60X0.6 No 2.14X0.2 Yes (5) 2.57X2.17X0.2 Example 10 3.50X1.3 2.75X0.6 Yes (7) 2.32X0.2 No 2.72X2.32X0.2 Example 11 3.50X1.3 2.75X0 .6 Yes ( ⁷ ) 2.34X0.2 No 2.74X2.34X0.2 Example 12 3.50X1.3 2.75X0.6 Yes (7) 2.33X0.2 No 2.73X2.33X0.2 Example 13 3.50X1.3 2.75X0.6 Yes (7) 2.31X0.2 No 2.71X2.31X0.2 Example 14 3.50X1.3 2.75X0.6 Yes) 2.30X0.2 No 2.70X2.30X0.2 Example 15 3.50X1.3 2.75X0.6 Yes (7) 2.32X0.2 No 2.72X2.32X0.2 Comparative Example 1 3.50X1.3 2.60X0.6 No 2.17X0.2 None 2.57X2.17X0.2 Comparative Example 2 3.50X1.3 2.60X0.6 None 2.17X0.2 None 2.57X2.17X0.2 Comparative example 3 3.50 1.3 2.60X0.6 None 2.20X0.2 None 2.60X2.20X0.2 Comparative example 4 3.50X1.3 2.60X0 .6 None 2.20X0.2 None 2.60X2.20X0.2 Comparative Example 5 3.50X1.3 2.60X0.6 None 2.17X0.2 Available (β> 2.60X2.20X0.2 Comparative Example 6 3.50X1.3 2.60X0. 6 None 2.13X0.2 None 2.53X2.13X0.2

Note: (1) Outer diameter x height.

(2) Inner diameter X depth.

(3) Ni plating layer.

(4) Outer diameter X inner diameter X height.

(5) A 15 m thick nickel plating layer was provided on the outer periphery of the disk-shaped yoke (the outer diameter of the plate-shaped yoke including the nickel plating layer was 2.17 m).

(6) Only a 15 μm thick Ni plating layer was formed on the outer periphery of the plate yoke (the outer diameter of the plate yoke including the Ni plating layer was 2.20 m).

(7) Similar to Fig. 10, the opening end force has an enlarged diameter part (inner diameter: 2.75 mm) to a depth of 0.30 mm, a diagonal step from 0.30 mm to 0.38 mm in depth, and an inner diameter in a part deeper than that. Was 2.60 mm.

[Table 2] Welding specifications

3]

Outer diameter of cup-shaped yoke Seal plate

X No magnetic attraction Example No. Burr Variation Small amount ζ <»Floating

m) Welding force (N)

(μνη) (mm; weight t, mm

Example 1 30 Yes No 2 12 0 6.38 Example 2 30 Yes No 2 12 0 6.43 Example 3 10 Yes No 2 4 0 6.43 Example 4 20 Yes No 2 8 0 6.43 Example 5 40 Yes No 2 16 0 6.43 Example 6 50 Yes No 4 20 0 6.43 Example 7 30 Yes No 2 12 0 6.33 Example 8 30 Yes No 2 12 0 6.33 Example 9 30 Yes No 2 12 0 6.43 Example 10 30 Yes No 2 12 0 6.62 Example 11 10 Yes No 2 4 0 6.62 Example 12 20 Yes No 2 8 0 6.62 Example 13 40 Yes No 2 16 0 6.62 Example 14 50 Yes No 4 20 0 6.62 Example 15 30 Yes No 2 12 0 6.52 Comparative Example 1 30 None None> 0.2 ― Comparative Example 2 30 None None--> 0.2 ― Comparative Example 3 0 None With 35 -20 0 6.23 Comparative Example 4 0 None With 35 -20 0 6.08 Comparative Example 5 0 None With 35 • 20 0 6.23 Comparative example 6 70 Yes No 10 ― 0 6.33

Note: (1) If the outside diameter of the cup-shaped yoke increases, the value is minus.

[0070] In order to measure the corrosion resistance of the denture attachments of Examples 1 and 8 and Comparative Examples 1 and 3, each sample was immersed in a 5% saline solution at 37 ° C for 3 days, and the occurrence of 鲭 in the weld was visually observed. Table 4 shows the results of the analysis of the saline solution for observation and for confirming whether or not the magnet was corroded.

[Table 4]

Example No. 発生 generated Saltwater analysis result

Example 1 None No detection of Nd

Example 8 None Nd was not detected in all numbers

Comparative Example 1 Yes Nd was detected in all samples

Comparative Example 3 Yes Nd was detected in all samples

From the above results, in the denture attachments of Examples 1 and 8, in which the spot welding was performed before performing the entire circumference welding, the saline solution was not applied to the concave portion of the cup-shaped yoke, but the spot welding was performed. In the denture attachments of Comparative Examples 1 and 3 in which the entire circumference was welded, it can be seen that the saline solution penetrated into the recess of the cup-shaped yoke.

Claims

The scope of the claims

[1] The seal comprises: a permanent magnet; a cup-shaped yoke made of a corrosion-resistant soft magnetic material having a recess for accommodating the permanent magnet; and a seal plate fitted into an opening of the recess of the cup-shaped yoke. The plate is composed of a plate-shaped yoke made of a corrosion-resistant soft magnetic material and a seal ring made of a corrosion-resistant non-magnetic material provided on the outer periphery of the plate-shaped yoke. A plurality of spot welds for fixing the butt portion, at least one full-circle weld formed to cover the butt portion between the cup-shaped yoke and the seal ring, and the butt portion between the seal ring and the plate-shaped yoke. A denture attachment, wherein the seal plate is joined to the cup-shaped yoke by a portion, whereby the permanent magnet is sealed.

[2] In the denture attachment according to claim 1, the cup-shaped yoke has a concave portion whose diameter is increased near an opening end, and the seal plate is fitted into the enlarged-diameter portion of the cup-shaped yoke. A plurality of spot-welded portions for fixing at least an enlarged portion of the cup-shaped yoke and an abutting portion of the seal ring; an abutting portion of the enlarged portion of the cup-shaped yoke and the seal ring; and the seal ring and the plate. The seal plate is joined to the cup-shaped yoke by at least one full-circumferential weld formed so as to cover the butted portion of the yoke, so that a magnetic gap is provided between the enlarged diameter portion and the permanent magnet. A denture attachment, wherein the permanent magnet is sealed in a state in which a permanent magnet is provided.

3. The denture attachment according to claim 2, wherein the step between the enlarged diameter portion and the concave portion is 20 to 200 μm.

[4] The denture attachment according to claim 1 or 2, wherein the spot-welded portion is formed at a butt portion between the power yoke and the seal ring, and at a butt portion between the seal ring and the plate-like yoke. A denture attachment characterized by being performed.

[5] The denture attachment according to any one of [14] to [14], wherein the entire circumference welded portion is formed so as to cover a butt portion between the cup-shaped yoke and the seal ring over the entire circumference. A denture attachment comprising: one welded portion; and a second welded portion formed so as to cover the butted portion of the seal ring and the plate-shaped yoke over the entire circumference.

[6] The denture attachment according to any one of [14] to [14], wherein the entire circumference welded portion includes a butt portion between the cup-shaped yoke and the seal ring, and a butt portion between the seal ring and the plate-shaped yoke. Characterized by being formed so as to integrally cover the entire circumference of the denture.

[7] The denture attachment according to any one of [16] to [16], wherein surfaces of the seal plate and the cup-shaped yoke are flattened after joining.

[8] The seal comprises a permanent magnet, a cup-shaped yoke made of a corrosion-resistant soft magnetic material having a recess for accommodating the permanent magnet, and a seal plate fitted in an opening of the recess of the cup-shaped yoke. The plate is composed of a plate-shaped yoke made of a corrosion-resistant soft magnetic material and a seal ring made of a corrosion-resistant non-magnetic material provided on the outer periphery of the plate-shaped yoke. The seal plate is joined to the cup-shaped yoke by an abutting portion and at least one full circumference welded portion formed so as to cover the abutting portion between the seal ring and the plate-like yoke. A denture attachment characterized in that, while being sealed, a region near the opening end of the cup-shaped yoke is reduced in diameter without substantially changing its width.

[9] A permanent magnet, a cup-shaped yoke made of a corrosion-resistant soft magnetic material having a concave portion that accommodates the permanent magnet and has an enlarged diameter near the open end, and is fitted into the enlarged-diameter portion of the cup-shaped yoke. A sealing plate made of a corrosion-resistant soft magnetic material, and a seal ring made of a corrosion-resistant non-magnetic material disposed on the outer periphery of the plate-shaped yoke. The seal plate is formed by at least one full circumferential weld formed to cover the butted portion of the cup-shaped yoke and the butted portion of the seal ring and the butted portion of the seal ring and the plate yoke. The permanent magnet is sealed in a state where a magnetic gap is provided between the enlarged-diameter portion and the permanent magnet, and the vicinity of the opening end of the cup-shaped yoke is joined to the cup-shaped yoke. Region dental attachment, characterized in that are reduced in diameter without substantial width changes.

10. The denture attachment according to claim 9, wherein a step between the enlarged diameter portion and the concave portion is 20 to 200 μm.

[11] A permanent magnet is housed in a concave portion of a cup-shaped yoke made of a corrosion-resistant soft magnetic material, and is made up of a plate-shaped yoke made of a corrosion-resistant soft magnetic material and a seal ring made of a corrosion-resistant non-magnetic material disposed around the yoke. A seal plate is fitted into the opening of the cup-shaped yoke, and at least a butt portion of the cup-shaped yoke and the seal ring is spot-welded at a plurality of locations to butt-join the cup-shaped yoke and the seal ring and the seal. A method of manufacturing a denture attachment, comprising: welding the cup-shaped yoke and the seal plate all around so as to cover the butted portion of the ring and the plate-shaped yoke.

[12] The method for manufacturing a denture attachment according to claim 11, wherein the butt portion between the cup-shaped yoke and the seal ring and the butt portion between the seal ring and the plate-shaped yoke are fixed at once. A method for manufacturing a denture attachment, wherein the spot welding is performed at a plurality of locations.

13. The method for manufacturing a denture attachment according to claim 11 or 12, wherein, as the entire circumference welding, the first welding is performed so as to cover a butt portion between the cup-shaped yoke and the seal ring over the entire circumference. Forming a second welded portion so as to cover the butted portion of the seal ring and the plate-shaped yoke over the entire circumference.

[14] The method for manufacturing a denture attachment according to claim 11 or 12, wherein a butt portion between the cup-shaped yoke and the seal ring, and a butt portion between the seal ring and the plate-shaped yoke are formed all around. A method for manufacturing a denture attachment, wherein the entire circumference is welded so as to cover the entire area integrally.

[15] The method for manufacturing a denture attachment according to any one of claims 11 to 14, wherein the seal plate and the cup-shaped yoke are subjected to planar processing after full circumference welding.