JPS6241412A - Fixing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixing device for fixing a fixed part to a synthetic resin molded part using a tapping screw.

[Conventional technology]

2. Description of the Related Art Synthetic resin molded products, such as plastic molded products, are easy to cut, so tapping screws are used in the plastic molded product to cut internal threads while fixing parts to be fixed.

As shown in FIG. 5, as a conventional fixing device, a pilot hole 2 for tapping a screw is formed in the mounting surface of a case body 1 molded from a plastic material, and a tapping screw 3 is tightened into the pilot hole 2 to secure the fixed part 4. There are known structures that fix the .

With this product, by screwing the tapping screw into the pilot hole 2 for tapping, the tapping screw will bite into the pilot hole 2 and cut the female thread, so it is possible to omit the tapping process for the female thread, and it is easy to install. It has the advantage of being extremely easy to perform.

[Problem to be solved by the invention]

In conventional equipment, when tightening the tapping screw,
Since the female thread is machined with plastic deformation on the female thread side, the rotational force of the self-tapping screw applies power to the pilot hole, causing the area around the opening of the pilot hole to bulge and impair the accuracy of the mounting surface. There is a drawback in that not only does this cause significant deterioration, but also that the embossed part becomes deformed over time, causing the mounting position of the fixed part to shift. This conventional device is used, for example, in optical disk pickups that require high mounting surface accuracy, and is equipped with a holder made of plastic, a polarizing beam splitter/prism unit, and a focusing unit.

When attaching a fixed component such as a photodiode using a mounting plate, the tightening of the self-tapping screws significantly deteriorates the precision of the mounting surface of the holder, causing the optical axis to shift significantly, making initial adjustment difficult, and also causing damage over time. Problems arise such as the optical characteristics becoming distorted.

This invention was made in view of these problems, and it improves the mounting accuracy of fixed parts, especially in optical disk pickups that require high-precision mounting.
It is an object of the present invention to provide a fixing device that can prevent positional displacement due to changes over time.

[Means and effects for solving the problem] The present invention provides a fixing device for tightening a tapping screw 12 to a synthetic resin molded part 11 to screw a fixed part 13.
As shown in the figure, around the opening of a pilot hole for tapping 11a formed on the mounting surface of the synthetic resin molded part 11, and as shown in FIG. 2, a tapping screw insertion hole 13a formed on the mounting surface of the fixed part 13. A gap 14 is formed in at least one side of the periphery of the opening of the screw, and the embossment formed at the opening of the tapped hole 11a when the tapping screw 12 is tightened is allowed to escape into the gap 14 to secure the fixed part. This allows for accurate installation of the parts 13.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Third
The figure shows the present invention applied to an optical disk pickup capable of correcting eccentricity and surface wobbling of an optical disk. This pickup serves as an optical system that focuses a beam of light from a light source onto a bit pattern of an optical disk and guides reflected light modulated by the bit pattern to a photoelectric element, with a focusing unit 21. An optical unit 24 that integrally incorporates a polarizing beam splitter 22 and a prism 23. A photodiode 25 is attached to a holder 26 molded from a synthetic resin material such as plastic.

Upper surface 26a of holder 26, which is a synthetic resin molded part.

The front side 26b and the right side 26c iC are respectively focusing units 21. Optical unit, ) 24,7 A mounting surface for fixing the fixed part of the Ototiode 25 is formed. As shown in Figure 4, a pilot hole 27 for tapping a screw is formed at a predetermined position, and a hole is inserted around the opening of the pilot hole 27. 28 is provided. Still focusing unit 21. optical unit 24
．． Insertion holes 31 into which the tapping screws 3o are inserted are formed in the mounting bases 29a-29c of the photodiodes 25 at predetermined positions, and holes +→ into which the adjustment jig H is attached are formed at predetermined positions.

The above-mentioned focusing unit 21. optical unit 2
4. With the mounting bases 29a-290 of the photodiode 25 stacked on the mounting surface of the holder 26, by screwing the tapping screws 30 into the pilot holes 27, female threads are cut in the pilot holes 27 and each fixed component is screwed. be done. At this time,
Tightening of the tapping screw 30 causes cracking to occur at the opening of the pilot hole 27.

Therefore, according to such a configuration, the tapping screw 3
In order to prevent the accuracy of the mounting surface of the holder 26 from deteriorating due to zero tightening, the holder 26 is provided with a force-singing unit)21. Optical unit 24. Photodiode 2
5 can be properly attached, and the initial adjustment of each fixed component can be easily performed. Moreover, by allowing the bulge 9 that occurs at the opening of the pilot hole 27 to escape into the counterbore 28, it is no longer affected by the bulge, making it possible to hold the fixed component in the best condition for a long period of time. The reliability of p1 products can be significantly increased.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without changing the gist.

For example, in the above embodiment, a counterbore was provided around the opening of the screw tapping pilot hole or a tapping screw insertion hole to form a void, but the void may also be formed by providing a chamfer instead of the counterbore. can.

〔Effect of the invention〕

According to this invention, it is possible to maintain good accuracy of the mounting surface of the synthetic resin molded part on which the fixed part is attached, so that the fixed part can be mounted properly and easily, and the position of the fixed part due to changes over time can be maintained. Misalignment can be prevented.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views for explaining the present invention in detail, FIG. 3 is an exploded view showing the schematic structure of an optical disk pickup to which the fixing device of the present invention is applied, and FIG. 4 is a cross-sectional view for explaining the present invention in detail. FIG. 3 is a sectional view showing an embodiment of the present invention applied to a pickup, and FIG. 5 is a sectional view showing a conventional fixing device. 11...Synthetic resin molded part 11a...Prepared hole for tapping 12...Tapping screw 13...Fixed part 13a...Tapping screw insertion hole 14...Gap 21...Focusing unit, 24...Optical unit 25...Photodiode 2
6...Holder 27-...Prepared hole for tapping 28
... Counterbore 30 ... Tapping screw 31 ...
Insertion hole Fig. 1 Fig. 2 Fig. 3 Insertion hole Fig. 4 fig. 3. Relationship with the case of the person making the amendment Patent applicant (037) Olympus Optical Industry Co., Ltd. 4, Agent 5, Spontaneous amendment 7, Contents of the amendment (1) The scope of the claims of the present application is corrected as shown in the attached sheet. . (2) Specification 8, page 3, line 12, page 5, lines 4 to 5, page 5, lines 10 to 11, page 5, lines 16 to 17 Row number. The words "Focusing unit" on page 6, line 2, page 6, line 15, and page $8, line 10 are corrected to read "actuator unit." (3) The word "prism" on page 5, line 5 of the same specification is corrected to read "critical angle prism." (4) Figure 3 of the drawing of this application is corrected as shown in the attached sheet. In a fixing device for screwing fixed parts with tapping screws, at least one of the area around the opening of the tapping hole formed in the synthetic resin molded part and the opening of the tapping screw insertion hole formed in the fixed part. A fixing device characterized in that a cavity is formed in the. (2) The fixing device according to claim 1, characterized in that a counterbore is provided around the opening of the screw tapping pilot hole or the tapping screw insertion hole to form a cavity. (3) The fixing device according to claim 1, wherein a gap is formed by chamfering around the opening of the tapped hole or the tapping screw insertion hole. Applicant: Olympus Optical Industry Co., Ltd.

Claims (3)

[Claims] (1) In a fixing device that screws a fixed part onto a synthetic resin molded part using a tapping screw, the tapping screw insertion hole is formed around the opening of the tapped hole formed in the synthetic resin molded part and in the fixed part. A fixing device characterized in that a gap is formed in at least one side of the periphery of the opening. (2) The fixing device according to claim 1, characterized in that a counterbore is provided around the opening of the screw tapping pilot hole or the tapping screw insertion hole to form a cavity. (3) The fixing device according to claim 1, characterized in that a gap is formed by chamfering around the opening of the tapped hole or the tapping screw insertion hole.