JPH0720630Y2 - Wheel support structure for pointer-type wristwatch - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a wheel train support structure for a pointer type wristwatch.

[Prior Art and its Problems] In recent years, the main plate and wheel bridge of the pointer type electronic timepiece are formed of synthetic resin, but the conventional synthetic resin is PPS.
Since (Polyphenylene sulfide) is the main component, the ground plate and the parts under the pressure of the train wheel are easily deformed when placed in a high temperature state, so the screws are likely to loosen, and the metal support post is formed. When press-fitting, cracks are likely to occur. In addition, burrs are apt to occur due to changes in temperature and pressure during molding, the molding conditions must be strictly controlled, and secondary processing such as finishing processing is required, resulting in poor productivity.

[Object of the Invention] The present invention was made in consideration of the above circumstances. The purpose of the present invention is that the structure and manufacture of the main plate and wheel bridge are simple, but the strength is sufficient, and (EN) It is an object to provide a wheel train support structure for a pointer type wristwatch in which the main plate and the train wheel bridge can be securely fixed.

[Summary of the Invention] In order to achieve the above object, the present invention forms a main plate for supporting a gear of a train wheel mechanism and a train wheel bridge with liquid crystal plastic containing about 30% of glass fiber. With
A metal pillar is press-fitted and fixed to a portion of the main plate located around the train wheel mechanism, a hole is formed in the train wheel bridge corresponding to the pillar, and a screw is screwed into the pillar through the hole to attach to the main plate. The train wheel bridge is fixed.

[Embodiment] An embodiment in which the present invention is applied to a train wheel mechanism of an electronic wristwatch will be described below with reference to the drawings.

1 to 3 show an analog movement of an electronic wrist watch. This analog movement is of a two-needle type and comprises a step motor 1 and a train wheel mechanism 2. The step motor 1 drives the train wheel mechanism 2, and the drive mechanism 2
Moves a pointer (not shown) to indicate the time.

That is, the step motor 1 is composed of a coil 1a, a stator 1b, a rotor 1c, etc., and the rotor 1c rotates half a turn each time a pulse signal is applied to the coil 1a. Has been. In this case, the rotor 1c is arranged in the circular hole of the stator 1b, and the upper and lower ends thereof are axially supported by the main plate 3 and the train wheel receiver 5, respectively.

The train wheel mechanism 2 transmits the rotation of the rotor 1c to a pointer (not shown), and includes an intermediate wheel 6, a second wheel (minute hand wheel) 7, a Hino back wheel 8, a hour wheel (hour hand wheel) 9, etc. The intermediate wheel 6, the center wheel 7, and the rear wheel 8 are arranged between the main plate 3 and the train wheel receiver 5, and the hour wheel 9 is provided on the lower surface side of the main plate 3. That is, the intermediate wheel 6 rotates by meshing with the rotor pinion 1d of the rotor 1c. The center wheel & pinion 7 rotates by meshing with the pinion 6a of the intermediate wheel 6, and its shaft constitutes the minute hand shaft 7b.
The base plate 3 is projected to the lower side, and a minute hand (not shown) is attached to the projected lower end. The Hino back wheel 8 rotates by meshing with the pinion 7a of the center wheel & pinion 7, and transmits the rotation to the hour wheel 9, and its shaft 8b projects below the main plate 3 and has a pinion at the lower end thereof. 8a is provided. The hour wheel 9 is rotated by meshing with a pinion 8a of the Hinoura wheel 8, and is inserted into the minute hand shaft 7b of the center wheel 7 and the bearing portion of the main plate 3.
It is rotatably supported by 3a. The train wheel bridge 5 is arranged on the columns 3b, 3b provided on the main plate 3, and the screws 10,
Fixed by 10.

The main plate 3 and the train wheel receiver 5 of the train wheel mechanism 2 configured as described above are formed of liquid crystal plastic (Liquid Crystal Polymer), which is a kind of polyester of the genus Rhodophyta, or a resin in which a filler is mixed with the liquid crystal plastic. ing. In this case, the filler is glass, carbon, whiskers of potassium titanate, whiskers of reduced potassium titanate or the like. Next, Table 1 below shows three mechanical properties of polyphenylene sulfide, liquid crystal plastic, and a case where glass fiber is used as a filler in the liquid crystal plastic.

Since the liquid crystal plastic has a higher-order structure, it has less molecular entanglement when melted, has a low melt viscosity, and has a linear expansion coefficient, a small shrinkage ratio due to the rigid molecular chain, and high mechanical strength. Therefore, if this liquid crystal plastis is used for the main plate 3 and the train wheel receiver 5 of the train wheel mechanism 2, the characteristics of thermal creep are good, and the deformation of the portion under pressure is small even when placed in a high temperature state, and the screws are loosened, etc. In addition, since it is also highly tough, it prevents cracking when press-fitting metal stanchions and can be installed well, and has low melt viscosity and good flowability, so burrs etc. are less likely to occur during molding, It is possible to mold with high precision and improve productivity. In particular, when potassium titanate is used as the filler, the strength can be increased, and when reduced potassium titanate is used, since it has conductivity, electrostatic charge can be prevented and adhesion of dust or the like can be prevented.

The invention is not limited to the electronic wristwatch as described above, but can be widely applied to other timepieces.

[Advantage of Invention] As described above, according to the wheel train support structure of the pointer type wristwatch of the present invention, the base plate for pivotally supporting the gears of the wheel train mechanism and the wheel train bridge are made of about 30% glass fiber. It is made of liquid crystal plastic that contains it, and metal columns are press-fitted and fixed to the part of the main plate located around the train wheel mechanism, and holes are formed in the train wheel bridge in correspondence with the columns, and screws are used to support the columns through the holes. Since the train wheel bridge is fixed to the main plate by screwing it into the main plate, not only the ground plate and the train wheel bridge have high mechanical strength but also good thermal creep characteristics, so pressure is applied at high temperature. Since there is little deformation of the part, there is no looseness of the screw, and since the toughness is high, it is possible to prevent the occurrence of cracks at the time of press-fitting the metal strut and securely attach it. Further, by adding about 30% of glass fiber, the strength can be improved, but the flowability is not impaired, burrs are less likely to occur during the molding, and the molding can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a partially exploded perspective view of an analog movement, FIG. 2 is its plan view, and FIG.
The figure is a sectional view thereof. 2 ... Train wheel mechanism, 3 ... Main plate, 5 ... Train wheel receiver.

Continuation of the front page (56) Reference JP-A-58-84258 (JP, A) Actually open 50-95963 (JP, U) Actually open 60-146878 (JP, U) Actual public Sho-56-23538 (JP , Y2) "Chemical Handbook" edited by the Chemical Handbook (Chemical Handbook) (Showa 57-10-10), published by Ohmsha. 912

Claims (1)

[Scope of utility model registration request] 1. A base plate made of synthetic resin, in which a step motor is mounted, and a bearing hole is formed to support one end of a shaft of a gear train of a train wheel mechanism for transmitting rotation of the step motor to a pointer, and the base plate. Is a wheel train support structure of a pointer type wristwatch having a wheel train bridge made of a synthetic resin in which a bearing hole for supporting the other end of the shaft of the gear wheel of the wheel train mechanism is formed. The train wheel bridge is made of liquid crystal plastic containing about 30% glass fiber, and a plurality of metal columns are press-fitted and fixed to a portion of the main plate located around the gear wheel of the train wheel mechanism. A plurality of holes are formed in the train wheel bridge so as to correspond to the columns, and a screw is screwed into the columns through the holes to fix the train wheel bridge to the main plate. Wheel train support structure.