JP2001194469A - Hand for clock and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hand for clock which can reduce the power consumption, and accordingly, can prolong the service life of a battery for clock by constituting the hand of a corrosion-resistance thin Mg alloy and designing the hand in a highly visible state, and to provide a method of manufacturing the hand. SOLUTION: The metallic hand for clock is made of an Mg alloy containing 0.15-2.0 wt.% Mn. The method of manufacturing the hand includes a step of manufacturing an Mg-alloy sheet, having a thickness of 100-300 μm by hot rolling the Mg alloy in the temperature range of 200-450 deg.C, a step of making pilot holes through the Mg-alloy sheet, and a step of blanking and push-back blanking the sheet into a hand-like shape. The method also includes a step of patterning the surface of the push-back blanked hand, a step of blanking through the push-back blanked hand form the sheet, and a step of performing surface finishing, such as plating, coating, printing, etc., on the hand for the clock.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timepiece pointer made of a thin Mg-based alloy having excellent corrosion resistance.

[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.

The above publication discloses a conventional method of manufacturing a timepiece hand by 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 hands, the power consumption tends to increase because the moment becomes large especially in the second hand of the timepiece hands. Further, the moment against the impact becomes large, so-called needle jump is apt to occur, and it is not suitable as a timepiece 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, magnesium alloy has a problem that the workability of the material itself is poor. In particular, it is considered difficult to process such a thin band material of about several tens to several hundreds of micrometers, and it has not been used as a timepiece pointer material so far.
Further, 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.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to reduce the power consumption of a watch battery by extending its life.
It is an object of the present invention to provide a timepiece pointer having a thin shape and excellent visibility, which has good corrosion resistance 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 timepiece hand made of metal, the timepiece hand is a Mg alloy containing Mn, and the Mg alloy contains 0.15 to 2.0 wt% of Mn. Manufacturing method of a watch hand made of a metal and a metal, a step of producing a Mg alloy plate having a thickness of 100 to 300 μm by hot rolling in a temperature range of 200 ° C. to 450 ° C., forming a pilot hole in the Mg alloy plate Performing a step of punching and pushing back the outer shape of the pointer to the plate material, a step of applying a pattern to the surface of the pushed back pointer, a step of pulling out the outer push back pointer from the plate material, and plating, painting, printing, etc. on the pointer. And a finishing step.

The Mg alloy has a specific gravity as low as about 1.8 to 2.0, is light in weight, is excellent in dent resistance and cutting workability, has small dimensional change, or has good vibration absorption.
If they have the same weight, they have the characteristics that they are rigid and have excellent bending strength as compared with Al alloy, copper and the like. Also,
Since it is a low melting point metal, it is applied to various products by a molding method such as die casting or thixomolding.

[0010] Mg alloy materials for casting include Mg-Al-based materials, Mg-Al-Zn materials and Mg-Al-Zn materials represented by AZ91 materials.
Zn-Zr system, Mg-Zn-RE system, Mg-Zr-Th
System, Mg-Mn system and the like are used. The wrought Mg alloy material is also Mg-Al-Zn represented by AZ31 material.
Mg-Mn system, Mg-Al system, Mg-Zn system,
Mg-Th type or the like is used.

[0011] For wrought materials, the addition amount of the alloy component is lower than that for casting, and 8 wt% of Al and 6 wt% of Zn are added.
The degree is the upper limit. This is the workability of Mg alloy,
That is, plastic working is performed hot because cold workability is poor, but when components such as Al and Zn are added at a high concentration, elongation is lacking. On the other hand, Mg-Mn
The system is characterized by low strength and corrosion resistance, but excellent workability. An AZ31 alloy, which is a Mg-Al-Zn-Mn alloy, has some problems in terms of corrosion resistance, but is an alloy excellent in strength and ductility.

[0012] As described above, these Mg alloy materials for rolling have poor corrosion resistance, have the disadvantage of being corroded in a salt water environment, and have poor workability in the cold state. It seemed difficult to process it, and it was thought that it could not be applied to watch hands.

[0013] The indicator for the Mg alloy timepiece of the present invention is an M-type watch for rolling.
g alloy material or an alloy component obtained by adding an element such as Y, Nd, Ce, La, etc. to a Mg alloy material for rolling excellent in elongation, and continuously processing the rolled thin Mg alloy sheet material,
The pointer material is formed by surface treatment.
Therefore, it is possible to manufacture a thin Mg alloy plate by ensuring the rollability, and the corrosion resistance is also improved at the same time.

In the pointer for a Mg-based alloy timepiece of the present invention,
The range of Mn of 0.15 to 2.0 wt% is a range in which some degree of corrosion resistance and elongation are compatible. If it is less than 0.15%, the corrosion resistance is greatly deteriorated, and if it exceeds 2.0 wt%, the plastic workability is poor. This tends to cause defects such as cracks and cracks during hot rolling.

The reason why the Al content is set to 0.5 to 6.5 wt% is that if it is less than 0.5%, there is a problem in corrosion resistance.
If it exceeds 5 wt%, the plastic workability is inferior. Zn
For the same reason, the content is set to 0.2 to 2.5 wt%, which is a range for achieving both corrosion resistance and ductility. Further, since Zn has a large specific gravity, addition of Zn exceeding 2.5 wt% is not preferable because it increases the specific gravity of the alloy itself.

In the pointer for an Mg-based alloy watch of the present invention,
The reason that Ln such as Y, La, Ce, and Nd is preferably 0.2% to 6.0% is that if it is less than 0.2%, there is a problem in terms of corrosion resistance, and if it exceeds 6.0%, the specific gravity becomes too large. It becomes large, and the function as a timepiece pointer, such as a needle jump or a decrease in power consumption due to an impact, is reduced, or the elongation of the material itself is reduced, and it becomes difficult to roll a thin plate material of about several hundred μm. It is.

As described above, brass,
The magnesium alloy of the present invention, which is thinner and has a lower specific gravity than conventional copper and aluminum materials, is effective. Mg of the present invention
In the alloy-based watch hands, the Mg content was 84.5 wt.
% Or more, since the lower the specific gravity becomes, the more effective the watch hand becomes. It is more preferable to set the value of the specific gravity to 2.0 or less.

[0018]

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS. 1 to 4 illustrate a method of manufacturing a timepiece hand for a second hand according to the present invention in the order of steps. The material used in this example was 95.7.
wt% Mg-3.0 wt% Al-1.0 wt% Zn-
An AZ31-based Mg alloy material represented by 0.30 wt% Mn was rolled by a plurality of steps such as rough rolling, hot rolling, and finish rolling to obtain a 200 μm-thick Mg alloy sheet material 2.
The Mg alloy plate 2 is continuously pressed to form a pilot hole 4 and a needle shaft hole 6 (FIG. 1). The pilot hole 4 is used for positioning during post-processing, and is shown in the conventional continuous press working. Next, as shown in FIG.
Push back into the hole that was immediately pulled out while pulling in between. Thereafter, the surface of the pointer 8 was diamond-cut, and a mirror cut pattern, which is a pattern, was applied to the surface of the pointer. As shown in FIG. 3, a crimping step of fixing the separately manufactured hakama 10 to the needle shaft hole 6 was performed. The plating 14 of Zn, Ni, Au, Ag, etc. was applied to the Mg alloy plate 2 including the hole 12. Then, the watch hands 8 were completed (FIG. 4).

As the evaluation method, 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. The corrosion resistance test is a case test, in which sodium chloride 50 g / L and cupric chloride 0.26 are used.
g / L, 2 ml / L acetic acid mixture in a tank at about 35 ° C. in an atmosphere of about 1.5 cc / hr / 80 cm ² for about 24 hours.
Due to the degree of discoloration of the surface of the test product when sprayed for hr, the test sample was evaluated as "good". In the power dissipation test, the present invention and the timepiece hands of the comparative example were incorporated into an actual timepiece, and the power consumption was measured. did.
The needle fly test was also evaluated as “good” by a hammer impact test for those equivalent or superior to aluminum watch hands.

Table 1 shows the results of evaluation of the second hand clock hands manufactured according to the first embodiment. It was found that the conventionally used brass-based Cu alloy, which is a comparative example, cannot obtain a power-dissipating effect. It is considered that this requires a high torque to drive the hands and has no effect on the low power consumption of the watch battery. In addition, good results were not obtained with respect to the needle flying property. It is considered that since the specific gravity of the material is as large as 8.2, the moment against the impact is high and the second hand cannot be held.

Table 2 shows the results of evaluation of timepiece hands for a second hand made with several different alloy compositions (weight percentages) in the same manner as in Example 1. The evaluation of workability in Table 2 was evaluated as acceptable (O) when the thin plate having a thickness of several hundreds of μm was processed or formed without generating cracks or cracks when a needle shaft hole or the like was formed. Other evaluations are the same as in Table 1.

As can be seen from Table 2, when the composition was out of the range of the present invention, the test results of workability, corrosion resistance and power consumption were not good. The Al content of 0.3% was rejected because of the problem of the corrosion resistance of the material itself although plating was performed. When the Al content was 9.0 wt%, cracks and cracks were generated during hot rolling, and a thin plate having good appearance could not be obtained. The alloy containing no Zn and the alloy containing 4.0 wt% failed in both the corrosion resistance and the workability. Further, since Zn has a large specific gravity, no significant effect was recognized in comparison with the Al watch hands in this test, so that the specific gravity of the alloy itself is increased, which is not preferable. Also, Mn showed good results within the scope of the present invention.

In addition, the alloy of the present invention which does not contain Al and Zn and which contains Mn exhibits good processing characteristics when the amount of Mn is within the range of the present invention. In addition, Mg-Al-Zn
Corrosion resistance was slightly inferior to -Mn alloys,
The improvement could be achieved by forming the plating layer thick, and the function evaluation as a timepiece guide such as a power dissipation test was also passed. Therefore, even in the case of the Mg-Mn system, good characteristics were exhibited within the composition range of the Mn addition amount of the present invention.

As described above, the timepiece made of the Mg alloy according to the present invention can reduce the torque for driving the hands, which is effective in reducing the power consumption of the timepiece battery.
Further, since the specific gravity is as low as about 1.8, the effect that the needle jump hardly occurs even in the case of impact was obtained.

(Embodiment 2) The second embodiment of the present invention
This will be described with reference to FIGS. 5 to 8 illustrate a method of manufacturing a timepiece hand for an hour and minute hand according to the present invention in the order of steps. The material used in this example is 92.
7 wt% Mg-3.0 wt% Al-1.0 wt% Zn-
A Mg alloy sheet 2 having a thickness of 200 μm, which was a Mg alloy material represented by 0.30 wt% Mn-4.0 wt% Y and rolled by a plurality of steps such as rough rolling, hot rolling, and finish rolling, was obtained. The Mg alloy plate 2 is continuously pressed and pressed,
The pilot hole 4 and the hole 12 are formed (the fifth hole).
Figure). The pilot hole 4 is used for positioning during post-processing, and is shown in the conventional continuous press working. The hole 12 fits into the pointer shaft of the machine body and is bent downward as shown in FIG. Next, as shown in FIG. 7, the outer profile of the timepiece hand 8 is pulled out between the pilot holes 4 and immediately pushed back into the drawn hole. Thereafter, the surface of the hands 8 is diamond-cut, and a mirror-like cut pattern, which is a pattern, is applied to the surface of the hands 8 so that the hands 8
Was completed (FIG. 8).

Table 3 shows the results of evaluation of the timepiece hands for the hour and minute hands, the comparative example using a brass-based Cu alloy, and several kinds of timepiece hands having different alloy compositions. Similar to the results with the second hand, the Mg alloy timepiece hands of the present example showed good results. Brass C of Comparative Example
Although there was no significant difference between the u alloy and the low power consumption of the watch battery, good results were not obtained in the needle jump test. It is considered that the timepiece hand for the hour and minute hands did not appear as a great effect because the required number of times of generation of the required torque was smaller than that of the second hand. Further, Nd is used as an Ln element.
Was selected, and the needle jump test failed even for the alloy added with 8 wt%, and the upper limit of the added amount of Ln element is preferably 6 wt% of the present invention. Further, an alloy containing no Ln element failed the corrosion resistance test, and is preferably in the range of the present invention with 0.2 wt% as the lower limit.

From the above results, it has been clarified that the timepiece hand made of the Mg alloy of the present invention is excellent in the low power consumption of the timepiece battery, the power dissipation effect and the like. As watch hands,
Visibility is a problem, but it is considered that the use of the Mg alloy of the present invention, which has a small specific gravity, can improve the visibility by increasing the area.

Although the second embodiment of the present invention has been described using Y as an additive element, similar effects can be obtained with La, Ce, Nd, and the like.

In the first embodiment, plating or painting is performed. However, a mirror-finished layer or a pattern layer to which decoration such as fluorescent paint is added may be finished by barrel polishing or the like. Conversely, in the second embodiment, a mirror-finished diamond cut is performed as a pattern layer, but plating or painting finish may be performed.

In the first embodiment, AZ is used as the second hand.
The description has been given of the 31-based Mg alloy and the alloy in which Y is added to the AZ31-based alloy for the hour and minute hands. However, there is no particular limitation, and any material may be used for either the second hand or the hour / minute hand.

In the first and second embodiments, M
g We used a strip as an alloy plate and performed continuous processing.
The processing may be performed using a fixed-size Mg alloy plate.

Further, in the second embodiment, the shank hole is formed by machining, but the shank hole may be formed separately and formed by a swaging step of caulking the needle shaft hole.

In the first embodiment, 95.7 watts is used.
t% Mg-3.0wt% Al-1.0wt% Zn-0.
AZ31-based Mg alloy material represented by 30 wt% Mn, JI
Although the explanation was given using the MP1 material in the S standard, if the corrosion resistance is enhanced by increasing the thickness of the surface treatment layer, other Mg-Z
Similar effects can be obtained by using n-Zr-based MP4, 5 materials, Mg-Al-Mn-based materials, and the like.

In the above-described second embodiment, the shank hole is formed by machining, but the shank hole may be formed separately and formed by a caulking step of caulking the needle shaft hole.

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[Table 1]

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[Table 2]

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[Table 3]

[0038]

According to the present invention, there is provided a timepiece hand made of a metal, wherein the timepiece hand is an Mg alloy containing Mn, and the Mg alloy contains 0.15 to 2.0 wt% of Mn. Producing a Mg alloy plate having a thickness of 100 to 300 μm by hot rolling in a temperature range of 200 ° C. to 450 ° C., wherein a pilot hole is formed in the Mg alloy plate. Forming, pushing out the outer shape in the shape of a pointer on the plate material, applying a pattern to the surface of the pushed-back pointer, removing the push-out pointer from the plate material, plating, painting, printing on the pointer, etc. By adopting the method of manufacturing a watch handpiece, which is characterized by comprising a step of finishing the surface of It possible to reduce the power consumption of meter battery is a long life, it was possible hands for a timepiece having an excellent design visibility obtained.

[Brief description of the drawings]

FIG. 1 shows a diagram in which a pilot hole and a needle shaft hole are formed in an Mg alloy plate according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a case where an outer profile of a timepiece hand is drawn between pilot holes and pushed back to a hole immediately removed;

FIG. 3 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. 4 is a conceptual diagram of a second hand of a timepiece hand according to the embodiment of the present invention.

FIG. 5 shows a diagram in which a pilot hole and a shank hole are formed in the Mg alloy sheet according to the embodiment of the present invention.

FIG. 6 is a view conceptually showing an AA ′ cross-sectional view of FIG. 5;

FIG. 7 is a conceptual diagram showing a state after the outer profile of the timepiece hand has been extracted between pilot holes and pushed back to the immediately removed hole.

FIG. 8 is a conceptual diagram of the hour and minute hands of the timepiece hand according to the embodiment of the present invention.

[Explanation of symbols]

 2 Mg alloy plate 4 Pilot hole 6 Needle shaft hole 8 Clock pointer 10 Hakama 12 Hakama hole 14 Plating

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Koji Fujii, Inventor Koji Fujimi, Tokorozawa-shi, Saitama Prefecture 840 Citizen Watch Co., Ltd. 840 Citizen Watch Co., Ltd.

Claims (9)

[Claims] 1. A timepiece hand made of a metal, wherein the timepiece hand is a magnesium alloy containing 0.15 to 2.0% by weight of Mn. 2. The watch hand according to claim 1, wherein the watch hand has a shaft hole and a surface finish layer in one end direction. 3. A watch hand comprising a metal, wherein the magnesium alloy has a general formula: MMaMnd (where a and d are 98.0 ≦ a ≦ 99.0, 1.0 ≦ d in weight percent).
The timepiece pointer according to claim 1 or 2, wherein the timepiece pointer is an alloy having a composition represented by ≤ 2.0). 4. A watch hand comprising a metal, wherein a magnesium alloy has a general formula: MgaAlbZncMnd (where a, b, c, and d are 90.5 ≦ a ≦ by weight percent.
99.15, 0.5 ≦ b ≦ 6.5, 0.2 ≦ c ≦ 2.
The timepiece indicator according to claim 1 or 2, wherein the alloy is an alloy having a composition represented by the formula: 5, 0.15≤d≤0.5). 5. A watch hand comprising a metal, wherein a magnesium alloy has a general formula: MgaAlbZncMndLn.
e (where Ln is 1 selected from Y, La, Ce, Nd)
A, b, c, d, and e are 84.5 ≦ a ≦ 98.95, 0.5 ≦
b ≦ 6.5, 0.2 ≦ c ≦ 2.5, 0.15 ≦ d ≦ 0.
The timepiece pointer according to claim 1 or 2, wherein the timepiece pointer is an alloy having a composition represented by the following formula: 5, 0.2 ≦ e ≦ 6.0). 6. 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. 7. The timepiece hand according to claim 1, wherein the timepiece hand has a shell structure. 8. A timepiece hand made of a metal having a needle shaft hole, wherein a hand strap is fixed to the needle shaft hole. Watch hands described. 9. A method for producing a timepiece hand made of metal, comprising: preparing a Mg alloy sheet having a thickness of 100 to 300 μm by hot rolling in a temperature range of 200 ° C. to 450 ° C. A step of forming a pilot hole, a step of punching out the outer shape in the shape of a pointer on the plate,
Manufacture of timepiece hands, characterized by having a process of applying a pattern to the surface of the pushed-back hands, a process of pulling out the outer shape of the pushed-back hands from a plate material, and a process of finishing the hands such as plating, painting and printing. Method.