JP2544553Y2 - Molded parts for precision equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded part used for assembling precision equipment such as a timepiece.

[0002]

2. Description of the Related Art In general, the hands of analog watches for automobiles are manufactured by a method of molding a plastic resin such as ABS. The structure of the mold molded product mld is determined by the structure of the mold. For example, as shown in FIG. 3, a vertical runner VR extending in the vertical direction and having a substantially L-shape formed with a resin injection path, and the vertical runner VR A horizontal main runner HR extending in a horizontal direction perpendicular to the VR, a plurality of tapered branch runners BR branched at predetermined intervals from the horizontal main runner HR, and a pointer wh joined to the tip of each branch runner BR It is composed of

[0003] Each of the hands wh thus formed in a mold is:
As shown in FIGS. 3 and 4, streamlines whose thickness gradually increases with respect to a front end and a rear end of the pointer wh in the longitudinal direction and a predetermined position (for example, the center of gravity) A near the rear end from the side. It is formed in a shape. In the predetermined position A area,
A press-fit hole HL into which a pointer shaft (not shown) is press-fitted is formed with a predetermined diameter so as to be orthogonal to the pointer direction.

[0004] In a state in which the molded component is integrally attached to the runner, for example, a gold plating process is performed on a surface as secondary processing. At the time of this gold plating treatment, a jig (not shown) for closing the press-fit hole HL of each guide wh is formed for the purpose of avoiding that the press-fit hole HL is gold-plated to make the hole diameter small and impossible to press-fit. A masking piece is attached. The masking piece is made of a rubber material or the like that is resistant to the acidic cleaning liquid used in the gold plating process.

A masking piece (not shown) is detached from the gold-plated pointer wh. Further, when assembling the analog timepiece, the hands wh are cut off from the branch runner BR, the tips of the hands are pressed into the press-fit holes HL, and the hour hand and the like of the analog timepiece are formed.

[0006]

However, in the conventional molded article, as described above, in the gold plating process as the secondary processing, the press-fit hole H of each molding guide pointer wh is used.
It is necessary to attach a masking piece, which is a jig for closing L, but a small masking piece of about several mm must be manufactured by another mold molding. Since the site and the masking site are generally different from each other, there is a problem that the masking piece is lost or complicated work is required due to an increase in the number of management steps.

In the gold plating process, it is necessary to attach electrodes and the like for electrical treatment. In the case of the above-mentioned conventional molded product, a molded product of a watch hand is integrally molded with a runner. for just that, it is necessary to provide etc. electrode mounting jig separately, also from this point which leads to such an increase in management steps.

Further, the pointer shaft of an automobile watch is generally made of metal, for example, brass such as BSP. When this brass pointer shaft is press-fitted into a press-fitting hole HL made of a plastic resin such as ABS, brass is used. Due to the difference between the heat shrinkage of the plastic and the heat shrinkage of the plastic, the holding force of the press-in hole HL to the pointer shaft is reduced due to the temperature difference from the assembly place, depending on the region where the automobile is sold, and the pointer wobble, and There are problems such as the deviation of the pointer.

The present invention has been made in view of the above circumstances, and has as its object to prevent loss of equipment and an increase in management man-hours, as well as for precision equipment capable of preventing deterioration of assembly accuracy due to a temperature difference. It is to provide a molded part.

[0010]

In order to achieve the above object, according to the present invention, there is provided a molded part for precision equipment which is formed integrally with a runner and has a hole for a mounting shaft. Is integrally formed with the component or the runner.

In the present invention, a chucking portion for secondary processing is integrally formed with the runner.

[0012] In the present invention, the insertion portion of the mounting shaft relative to the mounting shaft hole in the component, the bearing unit thermal shrinkage consisting mounting shaft and substantially the same members are integrally formed.

[0013]

According to the present invention, a closing jig integrally formed with a component or a runner is mounted in a hole formed in the component. This prevents the plating solution from entering the mounting shaft hole in the plating process or the like which is the secondary processing for the molded product. When the secondary processing is completed, the jig is detached from the hole, and is separated from the component when it is integrated with the component.

According to the present invention, for example, an electrode clip or the like is attached to the chucking portion during the secondary processing.

According to the present invention, one end of the mounting shaft is press-fitted into the bearing. In this case, since the heat shrinkage and the inner diameter of the mounting shaft to be press-fitted are substantially the same as the outer diameter of the shaft, the holding force of the mounting shaft hole with respect to the shaft is reduced even in a temperature environment different from that at the time of press-fitting. Never do.

[0016]

FIG. 1 is a perspective view showing an embodiment of a molded part for a timepiece according to the present invention, and FIG. 2 is an enlarged sectional view taken along line XX of FIG. 1 showing a conventional example. 3 and FIG. 4 are denoted by the same reference numerals. That is, MLD is a mold molded product, VR is a vertical runner, HR is a horizontal main runner, BR is a branch runner, WH is a pointer to be molded (part to be molded), MSP is a masking piece as a jig for closing a hole, THR indicates a thin film runner, HL indicates a press-fit hole, MHL indicates a bearing portion, and CHK indicates a chucking portion.

The masking piece MSP is composed of a disc-shaped base MSP _BS and a columnar pole MSP _PL formed substantially at the center of the upper surface of the base MSP _BS .
It is integrally formed with each of the formed guides WH via the thin film runner THR. That is, the masking piece MS
P and the thin film runner THR are each runner VR, H
R, BR and the same material as the molding guide WH, for example, AB
S and are integrally formed by the same mold forming process. The thickness of the thin-film runner THR is set to, for example, about 0.2 mm so as to have flexibility.

The pole portion MSP _PL is formed so as to protrude toward the bottom surface of the guide WH, and has a diameter substantially equal to that of the press-fit hole HL formed in the guide WH. The pole portion MSP _PL is inserted into the press-fit hole HL formed in the guide needle WH by bending the thin-film runner THR during a gold plating process as a secondary processing. When the secondary processing is completed, the pole portion MSP _PL is detached from the press-fit hole HL, and is separated from the thin film runner THR portion integrated with the forming guide WH.

Further, the press-fit hole HL in the guide WH to be molded is used.
The portion pointer shaft (not shown) during assembly of the analog clock is pressed against the same material as the pointer shaft, for example, BS
A bearing portion MHL made of P and having an inner diameter of the press-fit portion substantially equal to an outer diameter of the pointer shaft (for example, a difference of about 3%) is integrally formed. As shown in FIG. 2, the integral molding of the bearing portion MHL is performed by so-called insert molding, in which, for example, ABS is injected in a state where the BSP is arranged on the bottom surface of the pointer WH.

The chucking section CHK is a vertical runner V
At a predetermined distance from R, two branches are formed in parallel in a direction perpendicular to the vertical runner VR.

When the above-described mold molded product MLD is molded, a gold plating process is performed as a secondary process. In performing the gold plating process, an electrode clip or the like is attached to the chucking portion CHK. In addition, a masking piece MS integrally formed with each molding guide WH.
P pole part MSP _{PL of} P is bent into thin-film runner THR and inserted into press-fit hole HL formed in guide WH. Thereby, intrusion of the plating solution into the press-in hole HL is suppressed. That is, the plating treatment on the press-fitting hole HL is prevented, and the corrosion of the bearing portion MHL due to the acidic cleaning solution or the like is prevented. Therefore, the inner diameter of the press-fitting hole HL is stably maintained at the set value set at the time of die molding.

When the gold plating process is completed, an electrode clip and the like are removed from the chucking portion CHK.
The pole portion MSP _PL of the masking piece MSP is detached from the press-fit hole HL, and is separated from the thin film runner THR portion integrated with the molding guide WH.

The molded product MLD thus subjected to the gold plating is supplied to an analog watch assembly site. At the assembly site, the molded pointer WH is cut off from the branch runner BR, and one end of a pointer shaft made of a BSP (not shown) is pressed into the press-fit hole HL. In this case, since the bearing portion MHL into which the pointer shaft is press-fitted has substantially the same heat shrinkage and inner diameter as the pointer shaft and the outer diameter of the shaft, the press-fit hole HL is used even if the temperature environment is different from that during the press-fitting. The holding force of the bearing portion MHL on the pointer shaft does not decrease.

As described above, according to the present embodiment,
Since the masking piece MSP is integrally formed with the guide to be formed WH via the thin film runner THR, the masking piece MSP, which is a small equipment of about several mm, can be prevented from being lost, and an increase in the number of management steps can be prevented. In addition, since the chucking portion CHK is provided for the vertical runner VR, it is not necessary to separately provide an electrode mounting jig or the like, and this can prevent an increase in the number of management steps. Further, a portion pointer shaft against the press-fitting hole HL in the molded guidance WH is pressed, since the hand shaft and the heat shrinkage rate and the internal diameter was molded integrally with the bearing portion MHL is substantially the same as the axis diameter, Even if it is placed in a different temperature environment from the time of press fitting,
It is possible to prevent a decrease in the holding force of the press-fit hole HL on the pointer shaft of the bearing portion MHL, and to improve the reliability of the assembled analog timepiece.

In this embodiment, the case where the masking piece MSP and the thin film runner THR are integrally formed with each of the molding guides WH has been described as an example. However, the present invention is not limited to this. Lord Runner H
Even when integrally molded with various runners such as R and branch runner BR, the same effect as the above-described effect can be obtained. Also, the forming position and the shape of the chucking portion CHK are not limited to the present embodiment. Furthermore, in this embodiment, an analog timepiece has been described as an example of precision equipment. However, it is needless to say that the present invention can be applied to various precision equipment in which assembled parts are formed using micro-sized ones.

[0026]

[Effects of the Invention] As described above, according to the present invention,
Loss of equipment and increase in management man-hours can be prevented. Also,
Deterioration of assembly accuracy due to a temperature difference can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a timepiece molded part according to the present invention.

FIG. 2 is an enlarged sectional view taken along line XX of FIG. 1;

FIG. 3 is a perspective view showing one configuration example of a conventional molded part for a timepiece.

FIG. 4 is an enlarged cross-sectional view taken along a line YY in FIG. 3;

[Explanation of symbols]

 MLD: Molded product VR: Vertical runner HR: Horizontal main runner BR: Branch runner WH: Pointer (molded part) HL: Press-in hole MHL: Bearing part MSP: Masking piece THR: Thin film runner CHK: Chucking part

Claims (3)

(57) [Scope of request for utility model registration] 1. A molded part for precision equipment having a mounting shaft hole formed therein and integrally formed with a runner, wherein a jig capable of closing the mounting shaft hole is integrated with the component or the runner. Molded parts for precision equipment characterized by being molded. 2. The molded part for precision equipment according to claim 1, wherein a chucking portion for secondary processing is integrally formed with the runner. To 3. A hole for the mounting shaft in the part
Against the insertion portion of the mounting shaft, precision equipment molded part according to claim 1 or claim 2, wherein the bearing portion which thermal shrinkage consisting mounting shaft and substantially the same members are integrally formed.