JPH11304956A - Rotor for electronic clock and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a rotor for an electronic clock with a fixing force that is equal to or more than a prescribed force without causing a rotor magnet to be cracked inexpensively with a simple force-in method in a method for joining, by forcing a rotor shaft where a pinion and a shaft are formed integrally into the cylindrical rotor magnet where a rare earth bond magnet with a hollow part at a central part is covered with a metal plating film. SOLUTION: In a rotor for an electronic clock, a force-in length and a force-in margin are adjusted, thus preventing a rotor magnet 11 from being cracked when joining to a rotor shaft 12 and achieving a fixing force of the rotor shaft that is at least required as the rotor shaft of an electronic clock. In this case, in the rotor magnet 11, strength is improved by dipping an epoxy resin in the rare earth bond magnet, and further a single layer of plating of electroless Ni-P system or two layers of electroless Ni-P plating and electroless Ni plating are executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for an electronic timepiece of a converter used in an electronic timepiece and a method for manufacturing the same.

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for fixing a rotor shaft of a rotor of a converter used in an electronic timepiece to a rotor magnet and a method of manufacturing the same.

Conventionally, the joint between a rotor shaft and a rotor magnet is
This is done by several methods such as press-fitting and bonding.
Among them, joining by press-fitting using a low-cost bond magnet has advantages such as mass production and low-cost production.

[0004] However, the simple press-fitting has a problem that the rotor magnet may be cracked at the time of press-fitting.

Therefore, a method for solving the problem has been proposed in Japanese Utility Model Publication No. Sho 54-71610. One example will be described with reference to FIGS.

FIG. 3 is a sectional view of a conventional electronic timepiece rotor, and FIG. 4 is a sectional view taken along line AA 'of FIG. In FIG. 4, reference numeral 31 denotes a rotor magnet formed of a rare-earth sintered magnet, and reference numeral 32 denotes a rotor shaft integrally formed with kana. In FIG. 4, a part of the outer periphery of the rotor shaft 32 in which the pinions are integrally formed is cut, and has an uneven shape.

As shown in FIG. 3, the rotor shaft 32 is moved from the bottom to the top in FIG.
1 and is pushed into the rotor magnet 31 so as to be in contact with the entire inner peripheral length thereof. In this manner, the outer peripheral surface of the rotor shaft 32 is discontinuously formed at the time of press-fitting.
The rotor shaft 32 is inserted while being in contact with the inner peripheral surface of the rotor 1, and is joined to the rotor magnet 31 to prevent cracking of the rotor magnet during press-fitting.

[0008]

However, when the rotor magnet is a bonded magnet, there is a problem that the strength is small and the press-fitting margin cannot be increased, so that the probability of cracking increases and stable joining cannot be performed. Therefore, it has been a problem to find a joining method that can be joined without breaking the rotor magnet at the time of joining and that can obtain a sufficient fixing force of the rotor shaft.

As described above, how to bond a rotor shaft using a bond magnet which is lower in cost than a sintered magnet and by a simple press-fitting method is a major issue for realizing a low-cost rotor. Was. [Object of the Invention] The present invention solves the above-mentioned problems, and even when a bonded magnet is used, the rotor magnet can be joined without cracking at the time of joining, and a sufficient rotor shaft fixing force can be obtained. An object of the present invention is to provide a fixing structure for a magnet and a method for manufacturing the same.

[0010]

In order to achieve the above object, the electronic timepiece rotor of the present invention employs the following construction.

That is, an electronic timepiece rotor in which a rotor shaft having a kana and a shaft integrated therewith is press-fitted and joined to a cylindrical rotor magnet in which a rare-earth bonded magnet having a hollow portion at the center is coated with a metal plating film. By adjusting the press-fit length and the size of the press-fit allowance, respectively, the rotor magnet is not cracked when joined to the rotor shaft, and the rotor shaft is larger than that required for the electronic watch rotor shaft. Characterized in that it has a fixing force of

In the electronic timepiece rotor according to the second aspect, the press-fit length t of the configuration according to the first aspect is smaller than the height T of the rotor magnet after the plating film is covered.
/ 5 ≦ t ≦ T / 2, the press-fit allowance is in the range of 5 μm to 30 μm, and the fixing force of the rotor shaft is 0.2
kgf or more.

According to a third aspect of the present invention, in the electronic timepiece rotor according to the first or second aspect, the metal plating film formed on the rare earth bonded magnet is an electroless plating film. And

According to a fourth aspect of the present invention, in the electronic timepiece rotor according to the first, second or third aspect, the metal plating film formed on the rare-earth bonded magnet is made of an electroless Ni-P. Film, electroless Ni-B film or electroless Ni
And-at least one of a PW film.

According to a fifth aspect of the present invention, in the electronic timepiece rotor according to the first, second, third, or fourth aspect, the thickness of the formed metal plating film is one.
It is characterized by being at least 0 μm.

According to a sixth aspect of the present invention, in the electronic timepiece rotor according to the first or second aspect, the metal plating film formed on the rare-earth bonded magnet is an electroless plating film as a base plating film. The upper plating film is an electroplating film.

[0017] In the electronic timepiece rotor according to the seventh aspect, the metal plating film formed on the rare earth bonded magnet is not used as the base plating film in the configuration according to the first, second, or sixth aspect. Electrolytic Ni-P film, electroless Ni-B
At least one of the film and the electroless Ni-PW film is an electric Ni plating film as the upper plating film.

[0018] In the electronic timepiece rotor according to the eighth aspect, the metal plating film formed in any one of the first, second, sixth and seventh aspects is used as a base plating film. The thickness of the electrolytic plating film is 0.5μm or more and 2μ
m, and the thickness of the electroplating film as the upper plating film is 3 μm or more.

In order to achieve the above object, a method for manufacturing a rotor for an electronic timepiece according to the present invention employs the following configuration.

That is, a rotor for an electronic timepiece in which a rotor shaft in which a kana and a shaft are integrated is pressed into and joined to a cylindrical rotor magnet in which a rare-earth bonded magnet having a hollow center portion and a metal plating film is coated. In the manufacturing method, by adjusting the press-fit length and the size of the press-fit allowance, the rotor magnet does not crack when joined to the rotor shaft, and more than is required as a rotor shaft for an electronic timepiece. It is characterized by joining so as to have a fixing force of the rotor shaft.

According to a tenth aspect of the present invention, in the method for manufacturing an electronic timepiece rotor according to the ninth aspect, the press-fitting length t is smaller than the height T of the rotor magnet after the plating film is coated. / 5 ≦ t ≦ T / 2, the size of the press-fit allowance is in the range of 5 μm to 30 μm, and the fixing force of the rotor shaft is 0.2 kgf or more.

In the method for manufacturing a rotor for an electronic timepiece according to the eleventh aspect, in the configuration according to the ninth or tenth aspect, the rare earth bonded magnet is subjected to metal plating to change the film thickness. The size of the press fit is adjusted.

According to a twelfth aspect of the present invention, there is provided a method of manufacturing an electronic timepiece rotor.
1. The configuration according to 1, wherein the rare earth bonded magnet is impregnated with an adhesive in a vacuum, and then at least one metal plating of electroless Ni-P, electroless Ni-B or electroless Ni-PW is applied. And

According to a thirteenth aspect of the present invention, in the method of the ninth, tenth, eleventh or twelfth aspect, the thickness of the metal plating film to be formed is 10 μm. It is characterized by the above.

According to the method of manufacturing a rotor for an electronic timepiece according to the present invention, there is provided a method for manufacturing a rotor for an electronic timepiece.
In the configuration described in 1, the metal plating film formed on the rare earth bonded magnet is an electroless plating film as a base plating film and an electroplating film as an upper plating film.

In the method for manufacturing a rotor for an electronic timepiece according to a fifteenth aspect, in the ninth, tenth, eleventh, or fourteenth aspect, the rare earth bonded magnet is impregnated with an adhesive under vacuum. After that, electroless N
i-P film, electroless Ni-B film or electroless Ni-PW
At least one of the films is formed, and an electric Ni plating film is formed as an upper plating film.

In the method for manufacturing a rotor for an electronic timepiece according to a twelfth aspect of the present invention,
In the structure according to claim 14 or 15, the metal plating film to be formed has a thickness of the electroless plating film in the range of 0.5 μm to 2 μm as the base plating film, and the electroplating film as the upper plating film. The thickness is 3 μm or more.

That is, according to the present invention, in a method of joining a cylindrical rotor magnet made of a rare-earth bonded magnet and a rotor shaft having a kana and a shaft integrated, the rotor magnet is not broken and the fixing force is higher than a specified value. It is characterized in that the press-fit length and press-fit allowance are adjusted in order to obtain a joint.

Here, the press-fit portion and the press-fit length represent the following. That is, the press-fit portion is the rotor shaft 1
In a state after the joining of the rotor magnet 11 and the rotor magnet 11, the rotor shaft 12 and the rotor magnet 11 are portions in contact with each other in the hollow portion of the rotor magnet, and the press-fit length is the length of the portion. That is, in FIG. 1, the portion represented by the symbol t is the press-fit length.

As shown in FIG. 1, the inner diameter of the rotor magnet after coating with the plating film is b, the outer diameter of the press-fit portion of the rotor shaft is a (a> b), and ab is a press-fit margin. did. In addition,
Here, the specified fixing force is a fixing force of the rotor shaft after press-fitting which does not pose a problem in production and function in a rotor for an electronic timepiece, and is 0.2 kgf. Here, the fixing force refers to the rotor shaft 12 when the rotor magnet 11 is fixed and the rotor shaft 12 is pushed upward from below in FIG.
Is the load required to get out of the rotor magnet 11. Note that the fixing force of the rotor shaft in FIG. 2 is similarly defined.

Here, the reason why the press-fit length and press-fit allowance are limited as in the claims will be described. That is,
As a result of performing a destructive test of the rotor magnet when the rotor shaft was pressed into the rotor magnet while changing the press-fit length and the press-fit allowance, it was found that the above-described problem could be solved within a limited range of the press-fit length and the press-fit allowance. It depends.

A specific description will be given with reference to FIG. FIG.
1 is a sectional view of a rotor before and after a rotor shaft 12 is joined to a rotor magnet 11 according to the present invention. The rotor magnet 11 is made of a rare earth bonded magnet having a metal plating film 13. Press-fit length t
However, as described in claim 2, with respect to the height T of the rotor magnet after coating the plating film, T / 5 ≦ t ≦ T /
2, the shape of the rotor shaft is changed. That is, when t is smaller than T / 5, the rotor shaft is likely to be inclined regardless of the size of the press-fit allowance, and the shaft is likely to be misaligned. On the other hand, if it is larger than T / 2, the probability that the rotor magnet is cracked by press fitting increases.

Next, when the press-in allowance is smaller than 5 μm, the fixing force is smaller than 0.2 kgf. If the press-in allowance is larger than 30 μm, cracks may occur in the rotor magnet even if the press-in length is equal to or less than T / 2 described above. Therefore, as described in the claims, by limiting the press-fitting length and the press-fitting allowance, it is possible to prevent the magnet from cracking and to obtain a practical fixing force.

Next, according to the present invention, as described in the claims, after the rare earth bonded magnet is impregnated with an adhesive under vacuum, the electroless Ni-P, the electroless Ni-B or the electroless Ni
-P-W, wherein at least one metal plating is applied. In addition, as the adhesive, epoxy resin, phenol resin, which has relatively high adhesive strength and good workability,
Thermosetting adhesives such as polyurethane and anaerobic adhesives are preferred.

Here, the reason why the bonded magnet is impregnated with the adhesive in vacuum is to increase the breaking strength and reduce the brittleness.
This is for improving the mechanical strength of the rotor magnet. The reason why the metal plating film is applied is to improve the mechanical strength of the magnet itself and to prevent the magnet powder from falling off during the joining process. Thus, by vacuum impregnation of the adhesive and metal plating,
The strength and toughness of the bonded magnet material itself have been improved, and it has become possible to eliminate cracking of the magnet when the rotor shaft is press-fitted. In addition, for the crack of the magnet at the time of press fitting,
Neither vacuum impregnation of the adhesive nor metal plating alone is effective. This is because the rotor magnet surface has been smoothed by the impregnation of the adhesive, and the adhesion between the metal plating and the rotor magnet has been improved, thus improving the toughness. It is because of this.

Here, the reason why the plating thickness is limited to 10 μm or more is that if the plating thickness is less than 10 μm, the mechanical strength of the rotor magnet does not increase and the object of the present invention cannot be achieved. The plating thickness is desirably 30 μm or less from the viewpoint of controlling the plating thickness.

Next, in the present invention, after the rare earth bonded magnet is impregnated with an adhesive under vacuum, an electroless Ni—
P film, electroless Ni-B film or at least one of electroless Ni-PW film is formed, and an electric Ni plating film is formed as an upper plating film. The thickness of the electroless plating film as the base plating film is in the range of 0.5 μm to 2 μm, and the thickness of the electroplating film as the upper plating film is 3 μm or more.

The underlying plating layer is for imparting electrical conductivity to the surface of the rare earth bonded magnet, and the upper plating layer is smaller in plating than electroless plating alone due to the high adhesion and mechanical strength of electroplating. The same effect was obtained at a large thickness, the rotor magnet was not cracked, and the production of an electronic timepiece rotor by stable bonding became possible.

Here, as the electroless metal plating, Ni-
The reason why the electroplating is limited to Ni electroplating for P, Ni-B, Ni-PW and Ni electroplating is because the present inventors have found the following. That is, C
In the case of low-hardness metal plating such as u, Pd, Au, Sn, and solder (Pb / Sn-based), which has relatively high ductility, the improvement in the breaking strength of the rotor magnet is small. Further, the fixing force after the press-fit of the rotor shaft is low. On the other hand, Ni-P, Ni-B, Ni-P
-W electroless plating and electric Ni plating are relatively high in hardness and high in Young's modulus, and the increase in breaking strength as a rotor magnet after plating is large. In addition, a stable and high fixing force can be obtained.

Therefore, for these reasons, the type of plating for coating the rare earth bonded magnet is limited as described above.

(Operation) According to the present invention, in a rotor for an electronic timepiece in which a rotor shaft having a pinion and a shaft integrated therewith is pressed into and joined to a cylindrical rotor magnet made of a rare earth bonded magnet having a metal plating film. By press-fitting and joining the rotor shaft whose length and press allowance are adjusted, it is possible to manufacture a rotor having no crack at all and having a fixing force exceeding a specified value.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION The rare earth bonded magnet in the present invention may be any of SmCo, NdFeB and SmFeN. The adhesive used in vacuum impregnation may be a liquid, and is preferably a thermosetting adhesive such as an epoxy resin, a phenol resin, or a polyurethane, which is inexpensive, has high adhesive strength, and has good workability, or an anaerobic adhesive. When impregnation is performed, it is preferable to use a resin having better permeability and a lower viscosity.

It is an object of the present invention to provide a method for joining a rotor shaft to a rotor magnet made of a rare-earth bonded magnet by simple press-fitting, and an electronic timepiece rotor manufactured by the method. On the other hand, the object has been achieved by press-fitting and joining a rotor shaft whose press-fit length and press-fit allowance are adjusted to a rotor magnet which is a rare earth bonded magnet having metal plating.

Specifically, when the press-fit length t is T / 5 ≦ T with respect to the height T of the rotor magnet after coating the plating film.
t ≦ T / 2, and the size of the press-in allowance is 5 μm or more and 30 μm
m or less, and the fixing force of the rotor shaft is 0.2 kgf.
As described above, the purpose is achieved by adjusting the press-fit length and the press-fit margin and press-fitting and joining. Here, the rare earth bonded magnet is vacuum impregnated with epoxy resin to increase the strength and toughness.

Further, as metal plating, electroless Ni-
P, at least one metal plating of electroless Ni-B or electroless Ni-PW, or electroless Ni-P film, electroless Ni-B film or electroless Ni- Forming at least one of the P-W films, forming an electric Ni plating film as an upper plating film,
The use of the two-layer plating film structure makes it possible to provide an electronic timepiece rotor having stability against cracking of the rotor magnet and higher fixing force. The rotor shaft may have any cross-sectional shape. Therefore, the present invention can be carried out using a rotor shaft having a circular cross section, a concavo-convex shape as shown in FIG. 4, or any other shape.

[0046]

EXAMPLES (Example 1) Hereinafter, the present invention will be described with reference to examples. FIG. 1 is a sectional view showing an electronic timepiece rotor according to an embodiment of the present invention. FIG. 1A shows the electronic timepiece rotor after the rotor shaft has been pressed into the rotor magnet and joined thereto.
2 shows a rotor magnet which has been subjected to electroless Ni-P plating before joining. In FIG. 1, reference numeral 11 denotes a rotor magnet made of a rare-earth anisotropic bonded magnet using an Sm ₂ Co _17- based magnet powder and an epoxy resin as a binder, and 12 denotes a JIS S
The rotor shaft, which is formed of K4 material and has a pin and a shaft integrally formed, 14 is a metal plating film. In this embodiment, an electroless Ni-P film is used. Also, t is the press-fit length, a is the outer diameter of the press-fit portion of the rotor shaft, b is the inner diameter of the rotor magnet after coating the bond magnet with plating,
(Ab) is the press-fitting allowance.

That is, a rotor shaft having a press-fit portion outer diameter having a length a larger than b is press-fitted into a hollow portion of a rotor magnet having an inner diameter b of the magnet after plating and joined. As a result, the rotor magnet is deformed by ab, that is, the size of the press-fitting allowance, and the rotor shaft and the rotor magnet are joined.

The details of the rotor magnet used in this embodiment will be described. First, the dimensions before plating are φ1250 μm (outer diameter) × φ350 μm (inner diameter) × 460 μm (thickness). The bonded magnet is made of SmCo (2
-17 series) A bonded magnet made of magnet powder and 3% by weight of an epoxy resin binder and manufactured by compression magnetic field molding was used. Here, the average particle size of the magnet powder is a value measured by the Fischer method. 20-40% by volume of this bonded magnet
However, by filling this with a thermosetting liquid epoxy resin by a vacuum impregnation method, the mechanical strength and toughness were increased. Next, a uniform electroless Ni-P plating film having a thickness of 20 μm was formed on the entire bonded magnet by an electroless plating method to further increase the strength. As a result, the radial crushing strength of the bonded magnet was increased by 10 times or more than that before plating. If the plating thickness varies, the plating thickness may be set to be at least 20 μm, and the inner diameter may be finished with a drill having a diameter of 310 μm.

Next, as shown in Tables 1, 2 and 3, the press-fit length t of the rotor shaft 12 shown in FIG.
μm, 50 μm, 100 μm, 200 μm, 250 μ
m, 300 μm, and the outer diameter a of the press-fit portion of the rotor shaft is φ312 μm, φ315 μm,
φ320 μm, φ330 μm, φ340 μm, φ345
A μm rotor shaft 12 was prepared. Tables 1, 2 and 3 show the results of press fitting the rotor shafts 12 into the rotor magnets 11 and joining them.
As a result, if the press-in allowance is less than 5 μm, a fixing force of 0.2 kgf or more required for an electronic timepiece rotor cannot be obtained.
On the other hand, if it exceeds 30 μm, the rotor magnet may be cracked by press fitting. If the press-fit length is less than 100 μm, axial misalignment occurs. On the other hand, if the press-fit length exceeds 250 μm, the rotor magnet is cracked by press-fit. Therefore, the press-fit length is 10
It is necessary to set the size of the press-fitting to 0 μm or more and 250 μm or less, and the size of the press-fit allowance to 5 μm or more and 30 μm or less. Thus, Table 1,
In the range of the thick lines shown in Tables 2 and 3, it was found that the magnet did not crack, the fixing force was 0.2 kgf or more, and no axial displacement occurred. From this result, by setting the press-fit length and press-fit allowance of the rotor shaft to be as close as possible to the center value of this range, even if the dimensional variation of the outer diameter of the press-fit portion of the rotor shaft is taken into account, the simple construction of the rotor shaft is possible. Joining by press fitting has become possible on a mass production scale. That is, in the case of this embodiment, the height T of the rotor magnet after plating is T ≒ 460 + 2
0 × 2 = 500 μm. And T / 5 = 100μ
m, T / 2 = 250 μm. Accordingly, it has been found that the press-fit length t is such that the magnet does not crack in the range of T / 5 ≦ t ≦ T / 2, the fixing force is 0.2 kgf or more, and no axial displacement occurs.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

The dimensions of the rotor magnet for an electronic timepiece are as follows: an outer diameter of φ800 μm or more and φ1500 μm or less, an inner diameter of φ250 μm or more, φ500 μm or less, and a thickness of 40 μm or less.
If the range is 0 μm or more and 800 μm or less, the object of the present invention can be achieved. The object of the present invention can be achieved when the plating thickness is 10 μm or more. If the thickness exceeds 30 μm, it becomes difficult to control the plating thickness, and it is preferable that the thickness be 30 μm or less.

That is, even if the dimensions and the plating thickness of the rotor magnet are different from those of the present embodiment, if the dimensions and the plating thickness are within the ranges described above, the press-in length and the press-in allowance are shown in the claims. The object of the present invention can be achieved by making adjustments within the range. Further, in the present embodiment, the size of the press-fitting margin is adjusted by changing the outer diameter of the press-fitted portion of the rotor shaft, but may be adjusted by changing the thickness of the plating covering the rotor magnet.

As the adhesive used for the impregnation, a thermosetting adhesive such as an epoxy resin, a phenol resin, or a polyurethane having a relatively high adhesive strength and good workability, or an anaerobic adhesive can provide the same effect. Was.

(Embodiment 2) Hereinafter, the present invention will be described with reference to Embodiment 2. FIG. 2 is a sectional view showing an electronic timepiece rotor according to another embodiment of the present invention. FIG. 2A shows the electronic timepiece rotor after the rotor shaft 22 has been pressed into and joined to the rotor magnet 21.
FIG. 2 (b) shows electroless Ni-P plating and electric Ni before joining.
3 shows a rotor magnet coated with a plating film. In FIG. 2, the rotor magnet 21 is made of a rare earth anisotropic bonded magnet using an Sm ₂ Co ₁₇ based magnet powder and an epoxy resin as a binder. The rotor shaft 22 has a pinion and a shaft integrated with each other. In this embodiment, the lower metal plating film 24 is made of electroless Ni.
-P plating film is formed. Upper metal plating film 25
Is formed with an electric Ni plating film. In addition, t indicates the press-fit length, a indicates the outer diameter of the press-fit portion of the rotor shaft, b indicates the inner diameter of the rotor magnet after plating, and (ab) indicates the press-fit allowance.

The details of the rotor magnet used in this embodiment will be described. First, the dimensions before plating are φ1250 μm (outer diameter) × φ350 μm (inner diameter) × 488 μm (thickness). The bonded magnet is made of SmCo (2
-17 series) A bonded magnet made of magnet powder and 3% by weight of an epoxy resin binder and manufactured by compression magnetic field molding was used. Here, the average particle size of the magnet powder is a value measured by the Fischer method. 20-40% by volume of this bonded magnet
However, by filling this with a thermosetting liquid epoxy resin by a vacuum impregnation method, the mechanical strength and toughness were increased. Next, an electroless Ni-P plating film was formed as a base plating film so as to have a thickness of 1 μm, and an electric Ni plating film was formed as an upper plating film so as to have a uniform thickness of 5 μm. As a result, the radial crushing strength of the bonded magnet was increased by 10 times or more than that before plating. If the plating thickness varies, the plating thickness should be at least 6 μm,
The inner diameter may be finished with a 8 μm drill.

Next, as shown in Tables 4, 5 and 6, the press-fit length t of the rotor shaft 22 shown in FIG.
μm, 50 μm, 100 μm, 200 μm, 250 μ
m, 300 μm, and the outer diameter a of the press-fit portion of the rotor shaft is φ340 μm, φ343 μm, φ348 for each press-fit length t.
A rotor shaft 22 of μm, φ358 μm, φ368 μm, φ373 μm and made of JIS SK4 material was prepared. Tables 4, 5 and 6 show the results of press fitting these rotor shafts into the rotor magnets and joining them. As a result, if the press-fitting margin is less than 5 μm, the fixing force required for the electronic timepiece cannot be obtained, and if it exceeds 30 μm, the rotor magnet may be broken by the press-fitting. If the press-fit length is less than 100 μm, axial misalignment occurs. On the other hand, if the press-fit length exceeds 250 μm, the rotor magnet is cracked by press-fit. Therefore, the press-fit length must be 100 μm or more and 250 μm or less, and the size of the press-fit allowance must be 5 μm or more and 30 μm or less. As described above, it was found that the magnets did not crack, the fixing force was 0.2 kgf or more, and no axial displacement occurred in the range of the thick lines shown in Tables 4, 5, and 6. From this result, if the press-fit length and the press-fit allowance of the rotor shaft are made to be as close as possible to the center value of this range, even if the dimensional variation of the outer diameter of the press-fit portion of the rotor shaft is taken into consideration, the rotor shaft will not be deformed. Joining by simple press-fitting has become possible on a mass production scale. That is,
In the case of the present embodiment, the height T of the rotor magnet after plating is T
≒ 488 + (1 + 5) × 2 = 500 μm. Then, T / 5 = 100 μm and T / 2 = 250 μm.
Therefore, it has been found that the press-fitting length t does not break the magnet in the range of T / 5 ≦ t ≦ T / 2, the fixing force is 0.2 kgf or more, and no axial displacement occurs.

[0059]

[Table 4]

[0060]

[Table 5]

[0061]

[Table 6]

The dimensions of the timepiece rotor magnet are such that the outer diameter is not less than 800 μm and not more than 1500 μm, and the inner diameter is not more than φ1500 μm.
250μm or more, φ500μm or less, thickness 400μm
As described above, the object of the present invention can be achieved within the range of 800 μm or less. The object of the present invention can be achieved with a plating thickness of 3 μm or more including the two layers of the lower metal plating film and the upper metal plating film. In the present embodiment, the result is almost the same as the case of the single layer of only the electroless Ni-P plating film having the thickness of 20 μm shown in the embodiment 1 in which the thickness of the plating is 5 μm in total of the two layers. Therefore, even in the case of a thin plating film whose thickness can be easily controlled, the object of the present invention can be achieved by adopting the configuration as in this embodiment.

As an adhesive used for impregnation, a thermosetting adhesive such as an epoxy resin, a phenol resin, or a polyurethane having a relatively high adhesive strength and a good workability, or an anaerobic adhesive can provide the same effect. Was.

[0064]

As described above, according to the present invention, there is provided an electronic timepiece in which a rotor shaft having an integral pinion and a shaft is press-fitted and joined to a cylindrical rotor magnet made of a rare earth bonded magnet having a metal plating film. In the rotor, the press-fit length and the size of the press-fit allowance are adjusted respectively.

Accordingly, it has become possible to manufacture a rotor having no cracks and having a fixing force exceeding a specified value.

That is, the electronic timepiece rotor can be stably manufactured by a simple press-fitting method of the rotor shaft into the rotor magnet, and a low-cost electronic timepiece rotor can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electronic timepiece rotor showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an electronic timepiece rotor showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional electronic timepiece rotor.

FIG. 4 is a sectional view taken along line A-A 'of FIG.

[Explanation of symbols]

 11, 21, 31 Rotor magnet 12, 22, 32 Rotor shaft 13, 23, 33 Kana 14 Metal plating film 24 Lower metal plating film 25 Upper metal plating film T Height of rotor magnet after plating t Press-fit length a Rotor shaft Outer diameter of press-fitted part b Inner diameter of rotor magnet after plating c Outer diameter of rotor magnet after plating

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor ▲ Yosuke Sakaki ▼ Hara 840 Takeno, Shimotomi, Tokorozawa-shi, Saitama Prefecture Citizen Watch Co., Ltd. (72) Inventor Hiroshi Ikeda Shimotomi, Tokorozawa-shi, Saitama 840, Takeno, Citizen Watch Co., Ltd., Tokorozawa Office (72) Inventor Hidehashi Hashimoto, Tokorozawa, Saitama Prefecture

Claims (16)

[Claims] 1. A rotor for an electronic timepiece which is joined by press-fitting a rotor shaft in which a kana and a shaft are integrated into a cylindrical rotor magnet in which a rare-earth bonded magnet having a hollow portion at the center is coated with a metal plating film. By adjusting the press-fit length and the size of the press-fit allowance, respectively, the rotor magnet is not cracked when joined to the rotor shaft, and
An electronic timepiece rotor characterized by having a rotor shaft fixing force greater than that required for an electronic timepiece rotor shaft. 2. The press-fit length t is T / 5 ≦ t ≦ T / 2 with respect to the height T of the rotor magnet after coating the plating film.
2. The electronic timepiece rotor according to claim 1, wherein the press-fit allowance is in a range of 5 μm or more and 30 μm or less, and a fixing force of the rotor shaft is 0.2 kgf or more. 3. The electronic timepiece rotor according to claim 1, wherein the metal plating film formed on the rare-earth bonded magnet is an electroless plating film. 4. The method according to claim 1, wherein the metal plating film formed on the rare-earth bonded magnet is at least one of an electroless Ni-P film, an electroless Ni-B film and an electroless Ni-PW film. The electronic timepiece rotor according to claim 1, 2 or 3, wherein: 5. The thickness of the formed metal plating film is 1
5. The electronic timepiece rotor according to claim 1, wherein the thickness is 0 μm or more. 6. 6. The method according to claim 1, wherein the metal plating film formed on the rare-earth bonded magnet is an electroless plating film as a base plating film and an electroplating film as an upper plating film. Rotor for electronic clock. 7. The metal plating film formed on the rare earth bonded magnet is at least one of an electroless Ni-P film, an electroless Ni-B film and an electroless Ni-PW film as a base plating film, 7. An electric Ni plating film as the upper plating film.
2. The electronic timepiece rotor according to claim 1. 8. A metal plating film formed as a base plating film having a thickness of 0.5 μm or more and 2 μm or less.
m or less, and the thickness of the electroplating film as the upper plating film is 3 μm or more.
The electronic timepiece rotor according to claim 2, claim 6, or claim 7. 9. A rotor for an electronic timepiece in which a rotor shaft having a kana and a shaft integrated therewith is press-fitted and joined to a cylindrical rotor magnet in which a metal plating film is coated on a rare earth bonded magnet having a hollow portion at the center. A manufacturing method, wherein by adjusting a press-fit length and a size of a press-fit margin, a rotor magnet is not cracked when joined to a rotor shaft, and
A method for manufacturing a rotor for an electronic timepiece, wherein the joining is performed so as to have a fixing force of the rotor axis that is more than required as a rotor axis for the electronic timepiece. 10. The press-fit length t is T / 5 ≦ t ≦ T / T with respect to the height T of the rotor magnet after coating the plating film.
10. The method of manufacturing an electronic timepiece rotor according to claim 9, wherein the size of the press fit is in a range of 5 μm to 30 μm, and a fixing force of the rotor shaft is 0.2 kgf or more. 11. The electronic timepiece rotor according to claim 9, wherein the rare-earth bonded magnet is plated with metal and the film thickness is changed to adjust the size of the press-fitting allowance. Manufacturing method. 12. The method according to claim 1, wherein the rare-earth bonded magnet is vacuum impregnated with an adhesive, and then plated with at least one metal selected from the group consisting of electroless Ni-P, electroless Ni-B, and electroless Ni-PW. Claim 9, Claim 10, or Claim 1
2. The method for manufacturing an electronic timepiece rotor according to item 1. 13. A metal plating film to be formed having a thickness of 10 μm.
m, not less than m.
A method for manufacturing an electronic timepiece rotor according to claim 11. 14. The method according to claim 9, wherein the metal plating film formed on the rare earth bonded magnet is an electroless plating film as a base plating film and an electroplating film as an upper plating film. A manufacturing method of the electronic timepiece rotor described in the above. 15. After the rare earth bonded magnet is impregnated with an adhesive under vacuum, at least one of an electroless Ni-P film, an electroless Ni-B film and an electroless Ni-PW film is formed as a base plating film. 10. An electric Ni plating film is formed as the upper plating film.
The method for manufacturing an electronic timepiece rotor according to claim 11. 16. A metal plating film to be formed, wherein a thickness of an electroless plating film as a base plating film is in a range of 0.5 μm or more and 2 μm or less, and a thickness of an electroplating film as an upper plating film is 3 μm or more. The method for manufacturing a rotor for an electronic timepiece according to any one of claims 9, 10, 10, 11, 14, and 15, wherein: