JPH0634038B2 - How to fix the pipe of the watch case - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pipe fixing method for a watch case.

[Conventional technology]

In recent years, in watches, waterproof watches have become widespread and generalized. There is also a demand for full-scale, high-pressure waterproof watches for divers among waterproof watches, and there is a strong demand for improved reliability of waterproof functions and cost reduction. 1 and 2 show a method of fixing a pipe in a conventional waterproof timepiece.

In FIGS. 1 and 2, 1 is a pipe, 2 is a watch case, 3 is a fixing member and a sealing member, and the pipe 1 is a fixing member and a sealing member 3 which are press-fitted or simply inserted into the watch case 2. It is fixed with adhesive or brazing material.

[Problems to be Solved by the Invention]

With the conventional press-fitting and adhesive combination method shown in FIG. 1, the press-fitting length l cannot be infinitely increased due to the design of the timepiece, and the outer diameter d ₁ of the pipe and the through-hole diameter of the watch case A large fixing force could not be obtained in combination with the processing accuracy of d ₂ . Further, it is not possible to expect a great increase in the fixing force at the same time as the sealing with the adhesive, and the looseness of the pipe when the watch is carried causes a decrease in airtightness, resulting in poor reliability of waterproofing.

Further, in the pipe used for the crown of the high-pressure waterproof screw tightening system shown in FIG. 2, in the fixing method by brazing, depending on the material of the watch case and the pipe,
The wettability of the row is poor and it is difficult to secure a fixed force and airtightness. Sufficient brazing is possible depending on the selection of watch case, pipe material, brazing material, etc. However, from the viewpoint of corrosion resistance, the reliability of the waterproof function for long-term carrying is weak and not recommended.

Further, both the method of using an adhesive and the method of brazing impose a large number of man-hours due to the complexity of workability, and the use of an adhesive or a brazing material causes a high cost.

The object of the present invention is to eliminate the above-mentioned drawbacks, to firmly fix the two parts of the watch case and the pipe by welding, and to have a highly reliable waterproof function. This is to provide a pipe fixing method at a low cost that does not cause oxidation.

[Means for Solving the Problems]

 The constitution of the present invention is as follows.

In a method of fixing a pipe to a watch case by projection welding, a ring projection is formed over the entire circumference of the step on the outer circumference of the pipe and a step by an annular projection is formed on the inner circumference of the pipe, and the ring projection penetrates the watch case. Pressure contact with the step formed on the inner circumference of the hole, one electrode on the step on the inner circumference of the pipe and the other electrode on the watch case side, and between the electrodes in an inert gas atmosphere. By energizing, the pipe is resistance-welded to the watch case at the ring projection portion, and then the annular projection is removed.

〔Example〕

 Details of the present invention will be described according to examples.

3 to 6 show an embodiment of the present invention.

The watch case 2 and the pipe 1 are made of Ti, which has excellent corrosion resistance.
Using, the through hole 5 formed with the step portion 4 is processed in the timepiece case 2, the ring projection P is provided in the pipe 1 over the entire circumference of the step portion 6 in the outer circumference, and the annular projection 7 is provided in the inner circumference of the pipe. To form a step.

The diameter d ₂ of the through hole was set to be 30 μ larger than the outer diameter d _{1 of} the pipe so that the pipe 2 could be smoothly inserted into the through hole 5 of the watch case.

FIG. 5 shows a schematic view of a pipe during welding. The pipe 1 is inserted into the watch case 2 and one electrode 9 is attached to the watch case.
The other electrode 10 is brought into contact with the annular projection step portion 7a provided on the inner peripheral portion of the pipe 2, and after the ring projection is pressed by welding pressure, electricity is passed between the electrodes to perform resistance welding in an inert gas atmosphere. It was At this time, the welding pressure was 18 kgf and the peak current value was 2600A.

After the welding was completed, the annular projection on the inner circumference of the pipe was removed by machining to complete the process.

Waterproof function test of the pipe fixing part under pressure of 50 atmospheric pressure in water, 1
After maintaining for 0 minutes, good airtightness was obtained without any problems. Also, in the pipe pull-out test, 80 kg or more was obtained. By observing the fracture surface of the weld that was forcibly destroyed, it was confirmed that the pipe was welded uniformly over the entire circumference of the ring projection.

The feature of the present invention is that the power feeding surface on the pipe side is set to the step portion of the inner peripheral portion of the pipe to reduce the distance from the power feeding surface to the welded portion, and the welding pressure is transmitted uniformly and accurately during welding. That is, welding is performed in an inert gas atmosphere, and after welding, the step portion of the inner peripheral portion of the pipe is removed.

When the electrodes are brought into contact with the upper surface 8 of the pipe as a power feeding surface, the distance to the welding portion is large, and the electrical resistance of the pipe causes heat between the power feeding surface and the welding portion to cause softening. Therefore, the welding pressure causes deformation and the shape of the pipe cannot be maintained.
Not only is the shape of the pipe deformed, but the welding pressure is unstable, so good welding cannot be obtained.

The pipe deformation can be prevented by reducing the welding energy, but due to insufficient welding energy, heat generation is insufficient and welding with sufficient fixing force and airtightness cannot be obtained.

Further, by increasing the wall thickness of the pipe and reducing the electric resistance, it is possible to weld without causing deformation of the pipe, but the shape and size of the pipe increase and the crown also increases, which is not preferable in the design of the watch case.

As in the present invention, by reducing the distance from the power feeding surface to the welded portion, heat generation in the portion other than welding can be suppressed and welding energy can be effectively transmitted to the welded portion, and good welding can be obtained.

In order to obtain the power feeding surface near the welded portion, it is ideal to provide a step portion for the power feeding surface on the inner peripheral portion of the pipe without giving design restrictions to the watch case.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, the ring projection is provided on the step portion of the outer circumference of the pipe and the annular projections are provided on the inner circumference of the pipe, and the electrodes are brought into contact with the annular projections of the watch case and the pipe, respectively. This is a method of ring projection welding the pipe to the watch case in an inert gas atmosphere, and then removing the annular protrusion, so that sufficient fixing force of the pipe can be obtained, and at the same time airtightness that can withstand a high pressure waterproof watch is also achieved. This is an excellent method for fixing the held pipe, and since the pipe is fixed by welding, the processing cost can be made relatively low. Further, since the pipe is not deformed and the welded portion between the pipe and the watch case is hardly oxidized, the problem of corrosion resistance does not occur.

Furthermore, the length of the pipe inserted into the watch case can be reduced, and the design aspect such as narrowing of the watch case becomes very advantageous.

[Brief description of drawings]

1 to 2 are sectional views of a conventional pipe fixing method, FIGS. 3 to 6 show embodiments of the present invention, FIG. 3 is a sectional view of a watch case, FIG. 4 is a pipe, FIG. 5 is a schematic view of resistance welding of a watch case and a pipe, and FIG. 6 is a completed sectional view. 1, 11 ... Pipe, 2 ... Watch case, 3 ... Fixing member and sealing material, 4 ... Step, 5 ... Through hole, 6 ... Outer step, 7 ... Annular protrusion, 7a ... ... Steps of annular protrusion, 8
...... Pipe top, 9 ...... Electrode, 10 ...... Electrode, d ₁ ......
Outer diameter of pipe, d ₂ …… Diameter of through hole of watch case, l ……
Press-fit length, P ... Ring projection.

Claims (1)

[Claims] 1. A method for fixing a pipe to a watch case by projection welding, wherein a ring projection is formed over the entire circumference of a step on the outer circumference of the pipe and a step is formed by an annular projection on the inner circumference of the pipe. In pressure contact with the step formed on the inner circumference of the through hole of the watch case, one electrode on the step on the inner circumference of the pipe and the other electrode on the watch case, respectively, in an inert gas atmosphere. A method for fixing a pipe to a watch case, comprising energizing between the electrodes to resistance weld the pipe to the watch case at a portion of the ring projection, and then removing the annular protrusion.