JPH0650792Y2 - Wheel train guide structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a train wheel guide structure for a low-cost analog type timepiece.

[Purpose] It is an object of the present invention to provide an analog type timepiece having a timepiece structure made of a plastic member, which has a high quality train wheel guide structure and is made thin and low in cost.

[Prior Art] Conventionally, in analog timepieces, a main plate, a receiving member, and a train wheel constituting member that is a very small component are generally made of a metal material, and are used for insulating some circuit components and electronic circuits. Only plastic materials were used. However, it is a great demand of the market to provide a timepiece body with reduced cost by reducing the man-hours required for parts processing, and the provision of a timepiece body made of plastic such as a main plate, a bridge, and a train wheel is not a conventional method. It was possible to achieve a cost reduction of about half that of the metal material structure, and there was an urgent need for its practical application.

An example of such a conventional configuration is shown in FIG.

Referring to FIG. 2, reference numeral 1 is a base plate made of a plastic material, and 2 is a plastic rotor in which a magnet 3 is insert-formed. A fifth wheel & pinion 4 made of a plastic material is composed of a gear wheel 4-a and a pinion 4-b. 5
Is a fourth gear that meshes with a fifth pinion, and 6 is a second gear that meshes with a third pinion (not shown). Reference numeral 7 indicates a stator, and 9 indicates an hour wheel. Since each of them has a known function, detailed description is omitted. Reference numeral 8 denotes a train wheel bridge formed of a plastic material. As is clear from the figure, the lower handle 2-a, 4-c of the rotor and the fifth wheel is respectively in the main plate holes 1-a, 1-b and the upper handle 2-b, 4--.
d is loosely engaged with the train wheel receiving holes 8-a, 8-b and is guided and positioned. The train wheel bridge has sloped portions 8-c, 8-d corresponding to the displacement of the vehicle position, the collapse of the vehicle number and the like when the vehicle guide is incorporated, thereby improving the assembling property.

However, this conventional example has the following serious problems in terms of plastic processing characteristics. That is, each train wheel is guided by a handle hole provided on the main plate and the train wheel bridge, but at the end of the hole,
The risk of burr and burrs due to plastic is extremely high.

A molding die structure for molding the hole plastic is shown in FIG. 3 and will be described. Generally, the handle hole portion is formed by clamping with the A type and the B type according to FIG. 3, and the handle hole portion is the B type having the necessary handle diameter d portion on the A type surface. Guess
Form with no clearance. However, the pin tip B-1 portion provided on the B type must always have flatness, and a gap is generated due to sagging and die wear, and a pin tip dimensional deviation between the A type and B type clamping portions and the plastic is Partially filled,
Plane burr 8-g is generated. The burrs and the like eliminate the rattling of the train wheel, and there is a high risk of causing serious defects such as stoppage of the timepiece.
In addition, as shown in FIG. 2, the wheel train agaki is 1-c on the main plate side.
On the other hand, the train wheel receiving side is determined by the 8-e and 8-f faces, so the contact area is large and it is located on the outer peripheral side with respect to the car center, so torque loss due to friction etc. is large and it looks like a wristwatch. There was also a problem in terms of quality as a train wheel structure with a small holding torque.

[Problems to be Solved by the Invention] It is an object of the present invention to solve the problems of the conventional structure, and to provide a wheel train guide structure that reduces burrs of a plastic receiving member and has a small friction torque. .

[Means for Solving Problems] In a wheel train guide structure of a timepiece of the present invention, a reduction gear train composed of a plastic rotor in which a magnet is insert-molded and a gear made of a plastic material is a main plate and a bearing member of a train wheel bridge. In a train wheel guide structure of a timepiece supported between, the base plate and the train wheel bridge are made of a plastic material, one of the bearing members is a grooved bearing portion, and the other bearing member is a through hole. A bearing portion is formed, the plastic rotor is positioned by the shaft portion tip of the plastic rotor and the bearing portion, and the shaft portion tip is supported in the bearing portion without protruding from both the bearing members. It is characterized by being done.

[Example] An explanation will be given below with reference to FIG.

Referring to FIG. 1, 11 is a base plate formed of a plastic material, and 12 is a plastic rotor in which a magnet 13 is insert-formed. Reference numeral 14 is a fifth wheel and pinion made of plastic material, and is composed of a gear 14-a and a pinion 14-b. 15
Is a fourth gear that meshes with a fifth pinion, and 16 is a second gear that meshes with a third pinion (not shown). Reference numeral 17 indicates a stator, and 19 indicates an hour wheel. Since each of them has a known function, detailed description is omitted. 18 is a train wheel bridge made of a plastic material. As is clear from the figure, the undercarriage of the rotor and fifth wheel
12-a, 14-c are respectively in main plate holes 11-a, 11-b, upper handle 12-b,
14-d is loosely engaged with the train wheel receiving holes 18-a, 18-b and is guided and positioned. The train wheel bridge has sloped portions 18-c, 18-d corresponding to displacement of the vehicle position, tilting of the guard wheel, etc. when incorporating the vehicle guide, and improves the assemblability. Further, the wheel train receiving holes 18-a and 18-b of the wheel train bridge 18 are formed by recessed grooves, and the handle end wall thickness T for determining the wheel train clearance is T
Is about 0.2 to 0.25 mm due to the need for plastic filling.

According to this structure, burrs do not occur around the receiving hole of the train wheel bridge, and since the rotor and the gear are axially positioned at the tip of the handle to reduce the friction area, friction does not occur even if the plastic base plate and the receiving plate are used. The torque loss can be significantly reduced. The lower handle of the rotor is pivotally supported in a receiving hole 11-a which is a through hole of the main plate. This is because there is usually a burr 12-c at one end of the rotor shaft to avoid contact with the ground plane. Reference numeral 11-c is a support portion when the rotor largely moves in the axial direction due to an impact or the like.

[Effects] As described above, according to the present invention, since the bearing portion of one bearing member is a through hole, even if burrs are generated at the tip of the shaft portion of the plastic rotor in which the magnet is insert-molded, the burrs are Since it does not come into contact with, it is possible to avoid the rotation failure of the plastic rotor due to clogging of burrs.

Further, since the tip of the shaft portion of the plastic rotor is configured to be supported within the bearing portion of the main plate and the bearing member of the train wheel bridge, the metal needle collides with the tip of the shaft portion during lubrication. Since the shaft portion is deformed or a new burr is generated, it is possible to avoid the problem that the rotation failure of the plastic rotor occurs.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part showing a train wheel guide structure according to the present invention. FIG. 2 is a sectional view of an essential part showing a conventional train wheel guide structure. FIG. 3 is a view showing a forming die structure in a conventional train wheel guide structure. 11 ... Main plate 12 ... Rotor 14 ... Fifth wheel 18 ... Train wheel bridge

Claims (1)

[Scope of utility model registration request] 1. A train wheel guide structure for a timepiece, wherein a reduction gear train composed of a plastic rotor into which a magnet is insert-molded and a gear made of a plastic material is supported between a main plate and a bearing member of a train wheel bridge. And the train wheel bridge is formed of a plastic material, one of the bearing members is formed with a grooved bearing portion, and the other bearing member is formed with a through hole bearing portion, and the plastic rotor is formed of the plastic rotor. A wheel train guide structure for a timepiece characterized in that it is positioned by a tip of a shaft portion and the bearing portion, and the tip of the shaft portion is supported in the bearing portion without protruding from both the bearing members.