JP2001124869A - Hand for clock and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make reducible the power consumption of a battery material for clock and to provide a hand for clock, and its manufacturing method for designing it with excellent visibility by using a thinly shaped Mg alloy with good corrosion resistance. SOLUTION: This hand for clock is made of an amorphous Mg alloy represented by a general formula: MgaZnbXcLnd (X means one or more kinds of elements selected from among Ni and Cu, Ln means one or more kinds of elements selected from among Y, La, Ce, Nd, Sm or a mischmetal Mm as an aggregate of rare earth elements, while a, b, c, d mean atomic percentages: 60<=a<=90, 3<=b<=30, 0<=c<=30, 4<=d<=20). The hand for a clock has a shaft hole and a surface finished layer arranged in one side end, and is manufactured thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timepiece hand made of a thin amorphous Mg-based alloy having excellent corrosion resistance and a method of manufacturing a timepiece hand excellent in workability.

[0002]

2. Description of the Related Art Conventional timepiece hands are disclosed in Japanese Unexamined Patent Publication No.
As described in Japanese Patent No. 8186, a device using a brass or copper band material is disclosed, and is mainly used for hour and minute hands of a timepiece hand. For the second hand of the watch hand, a material using aluminum having a low specific gravity is also used.

As a conventional method of manufacturing a timepiece hand, the above-mentioned patent discloses a method of forming a band of about several hundred μm by continuous processing.

[0004]

However, in the case of conventional watch pointer materials using brass, copper, and aluminum, there have been design restrictions in the current trend of lower power consumption in recent years. That is, as a recent timepiece pointer material, to increase the area of the timepiece handpiece itself in order to improve the visibility, that is, the performance in which the time is easy to understand when looking at the timepiece, a fluorescent paint is applied to the outermost part of the timepiece hand. A design such as coating or adding an arrow is required. However, when the area is increased in order to enhance the visibility of the timepiece hand, the power consumption tends to increase because the moment becomes large especially in the second hand of the timepiece hand. Also,
The moment with respect to the impact is also increased, so that the so-called needle jump is liable to occur, and it is not suitable as a watch pointer.

To reduce the moment of the pointer,
It is conceivable to reduce the specific gravity of the material itself and to make it thinner. As a material having a low specific gravity, a magnesium alloy can be given. However, the magnesium alloy has poor workability of the material itself, and is generally hot worked. However, processing such as a thin strip of about several tens to several hundreds of micrometers is difficult, and is not suitable for a thin shape such as a watch handpiece. Further, since the specific strength is not different from that of aluminum, there is a limit to a thin shape, and a thinner shape has been desired. Further, the magnesium alloy has poor corrosion resistance of the material itself, and has a problem in practical use.

An object of the present invention is to solve the above-mentioned problems and to provide a timepiece pointer which has low power consumption, good corrosion resistance, a thin shape, and excellent workability, and a method of manufacturing the same. .

[0007]

Means for Solving the Problems In order to achieve the above object, a timepiece hand and a method of manufacturing the same according to the present invention employ the following timepiece hands and a method of manufacturing the same.

In a watch hand made of metal, the watch hand has a general formula: MgaZnbLnd [where Ln
Represents one or more elements selected from Y, La, Ce, Nd, and Sm, or a misch metal (Mm) which is an aggregate of rare earth elements, and a, b, and d are 6 atomic percent.
0 ≦ a ≦ 90, 10 ≦ b ≦ 30, 4 ≦ d ≦ 12], and is an amorphous Mg-based alloy having an axial hole and a surface finishing layer in one end direction. A watch hand, or a general formula: MgaZnbXcL
nd [however, X: one or two selected from Ni and Cu
More than one element, a, b, c, d are 6
0 ≦ a ≦ 85, 5 ≦ b ≦ 15, 5 ≦ c ≦ 20, 5 ≦ d ≦
15] This is a timepiece hand, characterized by being an amorphous Mg-based alloy having a composition represented by the formula [15] and having a shaft hole and a surface finishing layer in one end direction. Also, in the method for manufacturing a watch hand made of a metal, a step of producing a Mg-based alloy plate material of at least 30% (volume ratio) by amorphous by a liquid quenching method, a step of forming a pilot hole in the plate material, Steps of punching and pushing back the outline into the shape of the pointer on the plate, steps of applying a pattern to the surface of the pushed back pointer, steps of removing the pointer with the outer push back from the plate, steps of plating, painting, printing, etc. Or a method for manufacturing a watch hand made of metal, wherein at least 30% of the time is obtained by an injection molding method of a liquid quenching method.
(Volume ratio) The process of integrally forming a watch hand shape with an amorphous Mg-based alloy (volume ratio), the process of removing the forming needle of the hand, which is a molded product, and plating, painting, and printing the hands. And a method of manufacturing a timepiece hand.

As described above, generally, a crystalline Mg alloy material has a low specific gravity, but is inferior in corrosion resistance to Al, brass and the like. This is considered to be corrosion caused by the potential difference between the intermetallic compound formed in the crystal grain boundary and the like and the Mg matrix, and is avoided to some extent for Mg, which is an electrochemically noble element. This is a problem that cannot be solved. In addition, a crystalline Mg alloy has a problem of poor workability, and a thin strip-shaped wrought material is generally subjected to hot rolling, but has good corrosion resistance and ductility. Mg alloy satisfying the above condition has not been found.

On the other hand, an amorphous Mg alloy has excellent corrosion resistance because it has a structure in which solute particles are uniformly dissolved in an Mg matrix without crystal grain boundaries. Further, it has a feature of high strength, and even if the specific gravity is slightly higher than that of an existing crystalline Mg alloy, the specific strength is high, so that a thinner shape is possible. In addition, metal glass (amorphous alloy having a glass transition phenomenon) can be processed using viscous flow in a temperature range from a glass transition point Tg to a crystallization temperature Tx. The Mg alloy of the present invention
Since it is a low melting point alloy, it has the property of being excellent in melt flowability, and is suitable for injection molding and die casting.

The amorphous alloy of the present invention can be manufactured by a liquid quenching method. The liquid quenching method here is a method of rapidly cooling molten metal,
For example, a single-roll method, a twin-roll method, or a high-pressure casting method of casting at a high pressure such as die casting or injection molding is shown. The single-roll method and twin-roll method have a nozzle hole for injecting molten metal, and inject molten metal to a copper or steel roll rotating at a constant speed in the range of 100 to 10000 rpm to produce a ribbon. How to In the present invention, the Mg alloy obtained by adding Zn and a Ln (lanthanoid) element such as Y and La to Mg, when rapidly solidified by a liquid quenching method, an amorphous phase is obtained and excellent corrosion resistance is obtained. , Several tens mm wide by tens of mm by twin roll method
A ribbon having a thickness of several hundred μm can be obtained.

[0012] Further, Cu,
When elements such as Ni are added, the ability to form an amorphous phase is further improved, and since it is a low melting point alloy, the flowability of the molten metal is improved. Can be produced. In other words, the critical cooling rate required for forming the amorphous becomes lower, and even if the cooling rate is slightly reduced, the effect of easily becoming amorphous is exhibited.

In the pointer for an Mg-based alloy timepiece of the present invention,
The Cu and Ni contents are limited to 5 to 20% from the viewpoint of amorphous forming ability. If the Cu and Ni contents are not within this range, it becomes difficult to obtain an amorphous phase and the corrosion resistance is greatly deteriorated. . Further, in the pointer for the Mg-based alloy watch of the present invention, the Zn content is set to 10 to 30% or 5 to
The reason why the content is limited to 15% is from the viewpoint of corrosion resistance. If it is less than this range, the corrosion resistance is deteriorated, and if it is more than this range, the specific gravity becomes large, and it is not suitable as a timepiece hand.

As described above, the magnesium alloy of the present invention, which is thinner and has a lower specific gravity than conventional materials of brass, copper, and aluminum, is effective in reducing power consumption and improving the effect of suppressing needle jump. In the pointer for the Mg-based alloy watch of the present invention, the Mg content is limited to 60 to 90% because of this specific gravity. If the Mg content is not in the range of 60% or more, the power consumption is large, This is because the effect of suppressing the needle jump is also lost.

(Embodiment 1) A first embodiment of the present invention will be described. With a high frequency melting furnace, M having a predetermined component composition
An ingot of g alloy 4 is produced. The molten Mg alloy 4 is introduced into an injection tube 2 having a square injection hole (hole size: 0.5 × 30 mm) shown in FIG. An injection tube is installed directly above the copper roll 6, and the molten Mg alloy 4 is injected onto the copper roll 6 (φ300 × width 50mm) rotated at a high speed of about 4000 rpm, and rapidly solidified to a thickness of about 100 μm. A Mg alloy plate 8 made of a strip is obtained. 2 to 6 illustrate a method of manufacturing a timepiece hand of the present invention in the order of steps. The Mg alloy sheet material 8 is continuously pressed to form a pilot hole 10 and a hole 12. (FIG. 2) The pilot hole 10 is used for positioning during post-processing, and is shown in the conventional continuous press working. When the hour / minute hand is used as the timepiece hand, the hole 12 fits into the pointer shaft of the machine body and is bent downward as shown in FIG. 3 (section AA ′ in FIG. 2). In addition, the second hand is manufactured by a caulking step of caulking a separately manufactured hakama 14 into the needle shaft hole. (FIG. 4) Next, as shown in FIG. 5, the outer shape profile of the timepiece hand 18 is pulled out between the pilot holes 10 and pushed back into the hole immediately pulled out. Thereafter, the surface of the pointer 18 is diamond-cut, a mirror-cut pattern is formed on the surface of the pointer 18, and Cu, A is added to the Mg alloy plate 8 including the hole 12.
A plating 16 of u, Ag or the like is applied. And watch hands 18
Was completed. (FIG. 6)

As the evaluation method, a structural analysis by X-ray diffraction, a corrosion resistance test, a power dissipation test, and a needle jump test were performed, and a comprehensive evaluation was made as to whether or not the watch was suitable as a watch pointer. Structural analysis results by X-ray diffraction were measured at a diffraction angle in the range of 20 to 80 degrees, and amo indicated an amorphous single phase,
Indicates a crystalline phase, and amo + cry indicates a mixed phase of amorphous and crystalline. The corrosion resistance test is a case test, in which sodium chloride 50 g / l, cupric chloride 0.26 g / l,
Acetic acid 2 ml / l mixed solution is applied for about 24 hours at a rate of about 1.5 cc / hr / 80 cm 2 in a tank adjusted to an atmosphere of about 35 ° C.
Due to the degree of discoloration of the surface of the test article when sprayed, r was evaluated as being excellent. In the power dissipation test, the magnesium alloy timepiece of the present invention and the conventional aluminum timepiece were incorporated into an actual timepiece, and the power consumption was measured. ○ In the needle jump test, a hammer impact test indicated that the test piece superior to an aluminum timepiece pointer was evaluated as ○. In addition, in this test, the result when the second hand was used as a clock hand was shown.

Table 1 shows the results of evaluating the timepiece hands manufactured according to the first embodiment. “A” and “c” in Table 1 are when the Zn content is 10%. Discoloration occurs in the corrosion resistance test, and structural analysis shows that the mixed phase is amorphous and crystalline, and the corrosion resistance is deteriorated. Was. Also, e is a mixed phase because the addition amount of the Ln element is small,
Corrosion resistance was a poor result. In Table 1, l indicates that the specific gravity of the material itself was high and the shape was thinner than that of an aluminum watch hand. Mg alloys within the composition range of the present invention are b, d, f, g, h, and i in Table 1. All of the test results were good and showed excellent characteristics as a watch pointer material. .

(Embodiment 2) A second embodiment of the present invention will be described. With a high frequency melting furnace, M having a predetermined component composition
An ingot of g alloy 4 is produced. As shown in FIG. 7, using a hot-chamber die-casting apparatus 20, a melting pot 2 containing a Mg alloy 4 having the above composition and
2 and maintained at a temperature of about 450-600 ° C. The molding die 24 is designed to be able to take a large number of timepiece hands, and the die temperature is in a temperature range from normal temperature to 150 ° C. The molten metal of the Mg alloy 4 in the metal sleeve 30 contained in the gooseneck 28 is pressed into the timepiece forming die 24 by the press-fitting plunger lot 26. After press-fitting, the molded product is taken out and molded burrs and the like are removed. Next, the surface was mirror-smoothed by diamond cutting or barrel polishing or the like, followed by plating, painting, or other surface finishing to complete the hour / minute hands 18.

Table 2 shows the results of evaluation of the Mg alloy timepiece hands produced in the second embodiment described above. n and s are comparative samples, and although structurally amorphous characteristics were obtained, discoloration occurred in the corrosion resistance test. Also, r in Table 2
The alloy obtained by adding 5% of Cu and adding 20% of Zn caused discoloration in a corrosion resistance test, and was structurally a mixed phase of a crystalline phase and an amorphous phase. Also, o, which are compositions within the scope of the present invention.
As for the p, q, t, and u Mg alloys, the results of the corrosion resistance test, the power dissipation test, and the needle jump test were good, and they showed good characteristics as watch pointer materials.

Further, in the first and second embodiments, plating or painting is performed.
Alternatively, the pattern layer to which a decoration such as a fluorescent paint is added may be finished.

In the first embodiment, the strip is used for continuous processing, but the processing may be performed using a fixed-length material.

Further, in the preparation of the second hand of the first embodiment described above, a separately formed hand piece is fixed by caulking in the hand piece hole, but the hand piece hole is bent downward like an hour and minute hand, and the second hand and the hand piece are connected. It may be created integrally.

Further, in order to improve the strength of the timepiece hand, the hand has a substantially U-shaped cross-section, that is, a shell structure, so that the hand is less likely to be deformed due to an external impact. The strength can be improved by the guideline.

[0024]

According to the timepiece hand made of metal, the timepiece hand is represented by a general formula: MgaZnbLnd [L
n is one or more elements selected from Y, La, Ce, Nd and Sm, or a misch metal (Mm) which is an aggregate of rare earth elements, and a, b and d are 60 ≦ a ≦ 90, 10 ≦ b ≦ 30, 4 ≦ d ≦ 12], and is an amorphous Mg-based alloy,
A timepiece hand having a shaft hole and a surface finishing layer in one end direction, or a general formula: MgaZnbXc
Lnd [where X is one or more elements selected from Ni and Cu, a, b, c, and d are 60 ≦ a ≦ 85, 5 ≦ b ≦ 15, 5 ≦ c ≦ 20 in atomic percent, 5 ≦ d
≦ 15], which is an amorphous Mg-based alloy having an axial hole and a surface finishing layer in one end direction. Also, in the method for manufacturing a watch hand made of a metal, a step of producing a Mg-based alloy plate material of at least 30% (volume ratio) by amorphous by a liquid quenching method, a step of forming a pilot hole in the plate material, Steps of punching and pushing back the outline into the shape of the pointer on the plate, steps of applying a pattern to the surface of the pushed back pointer, steps of removing the pointer with the outer push back from the plate, steps of plating, painting, printing, etc. Or a method for manufacturing a watch hand made of metal, wherein at least 30% of the time is obtained by an injection molding method of a liquid quenching method.
(Volume ratio) The process of integrally forming a watch hand shape with an amorphous Mg-based alloy (volume ratio), the process of removing the forming needle of the hand, which is a molded product, and plating, painting, and printing the hands. And a method of manufacturing a timepiece hand. By adopting the above-mentioned timepiece hands and the method of manufacturing the same, low power consumption is achieved even for a hand shape having a large moment, the effect of suppressing hand jumps is improved, and a thin shape having good corrosion resistance is provided. Things became possible. In addition, since a timepiece hand can be formed by injection molding, workability is good and it is possible to manufacture the watch at low cost.

[0025]

[Table 1]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a single roll device for producing an Mg alloy sheet according to an embodiment of the present invention.

FIG. 2 shows a diagram in which a pilot hole and a hole are formed in an Mg alloy plate according to the embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA ′ of the hole shown in FIG. 2;

FIG. 4 is a conceptual diagram showing a second hand of the timepiece hand according to the embodiment of the present invention, in which a second hand is caulked.

FIG. 5 is a conceptual diagram showing the external profile of the timepiece hand after being extracted between pilot holes and pushed back to the immediately removed hole.

FIG. 6 is a conceptual diagram of the hour and minute hands of the timepiece hand according to the embodiment of the present invention.

FIG. 7 shows a hot chamber die casting apparatus for forming an Mg alloy according to an embodiment of the present invention.

[Explanation of symbols]

 2 Injection tube 4 Mg alloy 6 Copper roll 8 Mg alloy plate material 10 Pilot hole 12 Hakama hole 14 Hakama 16 Plating 18 Clock pointer 20 Hot chamber die casting device 22 Melting pot 24 Mold for molding 26 Press-in plunger lot 28 Gooseneck 30 Metal sleeve

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Sato 840 Takeno, Shimotomi, Tokorozawa-shi, Saitama Citizen Watch Co., Ltd. (72) Yoshitsugu Shibuya Takeno, Shimotomi, Tokorozawa-shi, Saitama 840 Citizen Watch Co., Ltd.Technical Research Laboratories (72) Inventor Seiichi Hiroe, Tokorozawa-shi, Saitama Prefecture 840 Shimotomi Takeno Citizen Watch Co., Ltd.Technical Research Laboratories No. 1-12 Citizen Watch Co., Ltd. Tanashi Factory (72) Inventor Kenji Ikeda 6-1-12 Honcho, Tanashi-shi, Tokyo Citizen Watch Co., Ltd. Tanashi Factory

Claims (10)

[Claims] 1. A watch hand comprising a metal, wherein the watch hand has a general formula: MgaZnbLnd [where Ln is one or more elements selected from Y, La, Ce, Nd and Sm, or The misch metal (Mm), which is an aggregate of rare earth elements, a, b, and d has a composition represented by the following formula: 60 ≦ a ≦ 90 10 ≦ b ≦ 304 4 ≦ d ≦ 12] A watch hand, characterized by having a shaft hole and a surface finishing layer in one end direction. 2. A watch hand made of metal, wherein the watch hand has a general formula: MgaZnbXcLnd [where, X: one or more elements selected from Ni and Cu, Ln: Y, La, Ce] , Nd, Sm, one or more elements, or a misch metal (Mm) which is an aggregate of rare earth elements, a, b, c, d
Is an Mg-based alloy having a composition represented by 60 ≦ a ≦ 85 5 ≦ b ≦ 155 5 ≦ c ≦ 205 ≦ d ≦ 15] in atomic percent, and an amorphous Mg-based alloy. A watch hand having a surface finish layer. 3. The timepiece hand according to claim 1, wherein the finishing layer comprises at least one of a mirror surface layer, a pattern layer, and a plating layer. 4. The timepiece hand according to claim 1, wherein the timepiece hand has a shell structure. 5. The timepiece hand according to claim 1, wherein a hook is fixed to the shaft hole. 6. A method of manufacturing a timepiece hand made of metal, wherein a step of manufacturing an Mg-based alloy sheet made of amorphous at least 30% (volume ratio) by a liquid quenching method, forming a pilot hole in said sheet. Process, punching and pushing back the outline of the pointer to the plate material, applying a pattern to the pushed back pointer surface, removing the push-backed pointer from the plate material, plating, painting, printing, etc. A method for producing a timepiece hand. 7. The Mg-based alloy sheet material is made of a strip material,
7. The method for producing a timepiece hand according to claim 6, wherein the band material is continuously processed to produce a timepiece hand. 8. A method for manufacturing a timepiece hand made of metal, wherein at least 30% is obtained by an injection molding method of a liquid quenching method.
(Volume ratio) The process of integrally forming a watch hand shape with an amorphous Mg-based alloy (volume ratio), the process of removing the forming needle of the hand, which is a molded product, and plating, painting, and printing the hands. And a method of manufacturing a watch hand. 9. The timepiece manufacturing method according to claim 6, wherein the Mg-based alloy comprises the amorphous Mg-based alloy according to claim 1. 10. The Mg-based alloy according to claim 2, wherein the Mg-based alloy is an amorphous Mg-based alloy.
A method for producing a timepiece hand according to claim 7.