JPH0575552U - Gear coupling structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a gear coupling structure that is easy to assemble even with a small gear coupling and has little gear wear. A structure in which a metal pin is coupled to a shaft of a plastic gear, and a through hole for inserting the shaft of the gear is formed in the shaft center of the metal pin to form the pin. The gear was inserted into the shaft of the gear, and the base end face of the shaft and the insert end face of the pin were fitted in a concavo-convex manner to form a retaining portion for preventing the pin from coming off at the tip of the shaft.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a gear coupling structure for coupling a metal pinion to a shaft of a plastic gear.

[0002]

[Prior Art]

 Gears of recent years include those made of metal and those made of plastic, and when these are used together, various usage conditions must be considered.

[0003] For example, modern timepiece gears (gear and shaft) are being integrally formed of plastic, but the minute hand wheel of these gears must have a structure that slips at the time of correction, and therefore the minute hand wheel is Only the minute hand shaft was made of plastic, and the minute hand wheel made of metal was integrated with the minute hand shaft by insert molding. The metal minute hand wheel meshes with the third pinion, but if the third pinion is made of plastic, there are the following problems.

The slip torque of the minute hand wheel changes due to the operating temperature because a predetermined torque is obtained by utilizing the contraction during plastic molding. For example, an automobile watch has a working temperature range of -30 ° to 80 °, but the torque at a low temperature becomes large, and when the time is adjusted at a low temperature, a relatively thin metal minute hand gear is made of plastic. There was a case that the number kana was damaged. Also, in the case of a watch with a large hand movement torque, especially in the case of a step hand movement, it could be damaged during long-term use.

[0005]

[Problems to be solved by the device]

 Therefore, it is conceivable to insert-mold the third pinion into the plastic third axle, which is made of metal, like the minute hand wheel. However, the third pinion is extremely small compared to the minute hand gear, and it is technically difficult to integrate it by insert molding.

The present invention has been made for the purpose of providing a structure for reliably fixing a metal pinion to a plastic gear under such an actual condition.

[0007]

[Means for Solving the Problems]

 That is, the gear coupling structure of the present invention is a structure in which a metal can is coupled to the shaft of a plastic gear, and the shaft of the gear is inserted into the shaft center of the metal pin. A mounting hole is formed and the pin is inserted into the shaft of the gear, and the base end face of the shaft and the end face of the pin to be inserted are recessed and engaged, and a retaining portion for preventing pin disengagement is formed at the end of the shaft. It was done. As a means for forming the retaining portion, an appropriate means such as caulking, fusion bonding or the like is used.

[0008]

[Action]

 According to the gear coupling structure of the present invention, a gear with a pinion can be obtained simply by inserting a pin into the shaft of the pin and forming a retaining portion at the tip of the pin. This assembling work is easy even if the pinion is extremely small. Then, the pinion is bound by the retaining portion and does not come off, and the pinion rotates integrally with the shaft (gear) due to the above-mentioned recess and protrusion fitting.

[0009]

【Example】

 Hereinafter, description will be given with reference to the accompanying drawings. 1 and 2 show a first embodiment of the present invention, in which reference numeral 1 denotes a step formed on the bottom of a plastic gear (the gear itself is not shown). Reference numeral 2 denotes a shaft projectingly provided on the bottom surface of the step portion 1, and the bottom surface of the step portion 1 is referred to as a base end surface 3.

Reference numeral 4 is a metal pinion, and a through hole 5 into which the shaft 2 is inserted is formed in the shaft center of the pinion 4. Further, 6 indicates a tooth groove of the pinion 4.

Further, in the first embodiment, the protrusion 7 that meshes with the tooth groove 6 is formed on the base end face 3 of the shaft 2. That is, in the first embodiment, the shaft 2 is inserted into the through hole 5 of the pinion 4, the protrusion 7 is engaged with the tooth groove 6, and the tip of the shaft 2 is fused under this state. Then, the retaining portion 8 is formed. In the first embodiment, the tooth groove 6 and the protrusion 7 are fitted in a concavo-convex shape to prevent the rotation.

FIG. 3 and FIG. 4 show a second embodiment of the present invention, in which a concave portion 9 corresponding to the shape of the inserting tip of the pinion 4 is formed in the base end face 3. ing. That is, in the second embodiment, the shaft 2 is inserted into the through hole 5 of the pinion 4, the insertion tip of the pinion 4 is fitted into the recess 9, and under this condition, the shaft 2 is pulled out. The stopper 8 is formed. In this embodiment, in the second embodiment, the rotation stopper is achieved by the concave and convex fitting of the insertion tip portion of the pinion 4 and the concave portion 9.

FIG. 5 is a usage example in which the above-described gear of the present invention is used in the timepiece train wheel.

In the drawing, A is a rotor, B is a rotor cana, C is a fifth wheel that meshes with the rotor cana B, D is a fifth wheel, E is a fourth wheel that meshes with the fifth cana, F is a fourth wheel, G is a plastic third wheel that meshes with the fourth Cana F and has a metal third Cana H. Reference numeral I denotes a metal minute hand wheel, which meshes with the third pin Kana H. J is a rear wheel of the sun and meshes with the hour hand wheel K.

As shown in the figure, the third kana H is extremely small. However, if the present invention is applied to the third wheel and the third pin, the small metal third pin H can be easily attached to the plastic third wheel G. Since the third kana is made of metal, even if the minute hand wheel is made of metal, it can be used for many years.

In the above description, the gear of a timepiece is taken as an example, but the gear coupling structure of the present invention can be used in all fields where small gears made of plastic and metal are used (for example, the field of toys). is there.

[0017]

[Effect of the device]

 As described above, according to the gear coupling structure of the present invention, a structure with a pinion that rotates integrally with the gear can be obtained. As described above, according to the present invention, even an extremely small gear can be easily assembled, the operating temperature range is limited, and the gear to be meshed with is made of metal and is easily worn or damaged. It is also effective when you want to use it for many years.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a first embodiment.

FIG. 2 is a front view of the first embodiment.

FIG. 3 is an exploded perspective view of the second embodiment.

FIG. 4 is a front view of the second embodiment.

FIG. 5 is a cross-sectional view of a usage example.

[Explanation of symbols]

 1 Step of gear 2 Shaft 3 Base end face 4 Cana 5 Penetration hole 8 Retaining part

Claims (1)

[Scope of utility model registration request] 1. A structure in which a metal pin is coupled to a shaft of a plastic gear, and a through hole for inserting the shaft of the gear is formed in the shaft center of the metal pin. A gear is characterized in that the pinion is inserted into the shaft of the gear, and the base end face of the shaft and the insertion end face of the pinion are fitted in a concavo-convex shape to form a retaining portion for preventing the pinion from coming off at the tip end of the shaft. Bond structure.