JPS6126947Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a structure for preventing pointer fluctuation of an electronic timepiece whose hands are operated using a crystal oscillation type step motor.

Conventionally, in this type of wobbling prevention structure, a regulating pawl is provided at the tip of a regulating spring and the regulating pawl is engaged with a certain gear of the gear train to fix the gear train, or the gear train is fixed by a pressing spring. The gear train is fixed by holding down the end face of the shaft or the side of the shaft.

However, according to the conventional prevention structure, in the case of the former, it is necessary to adjust the regulating pawl and the gear during assembly, and the regulating pawl generates load torque when the gear is driven, and furthermore, the regulating pawl causes the gear to The tip of the tooth abutted against the tip of the tooth, causing a so-called jamming condition, which caused the tooth to stop. In addition, in the latter case, the pressure spring presses down the end or side surface of the wheel train shaft, which generates a load torque when the wheel train is driven, and the wheel train is not sufficiently fixed and the moment of inertia of the pointer increases. It is forced to assist by keeping it small, and is subject to constraints on the design of the guideline.

In view of the above-mentioned circumstances, the present invention relates to a pointer fluctuation prevention structure for an electronic timepiece that eliminates the fluctuation of the pointer as much as possible and eliminates the fluctuation of the stop position of the pointer due to the backlash of the wheel train.

FIG. 1 is a sectional view of the vicinity of a step motor showing an embodiment of the present invention, and the present invention will be further explained below based on this figure. Reference numeral 1 in the figure is a step motor, which is composed of a stator 2, a rotor 3, and a rotor pinion 4. The rotor 3 has two stators 2,
2 and is fixed to the shaft portion 4a of the rotor pinion 4, and the rotor 3 is intermittently rotated by the input of drive pulses to the stator 2, thereby serving as a driving source for the timepiece. The rotor pinion 4 meshes with a drive gear 5 which is an adjacent intermediate gear. The drive gear 5 is one in the gear train.
A tapered engagement portion 5c is provided in the shaft portion 5a near the attachment portion of the gear portion 5b. This shaft portion 5a passes through a hole 7 formed in a support plate spring 6 fixed to the stator 2.

FIG. 2 is an enlarged view of the support leaf spring 6. This support plate spring 6 is a thin strip-shaped one, and one end of the fixed part 6a is securely fixed to the upper surface of the stator 2 by spot welding or the like, and the lower surface of the support part 6b is bent at an acute angle from the fixed part 6a. A small piece 8 of soft magnetic material is fixed to the stator side with adhesive or the like. Support part 6
The tip 6c of b is bent approximately parallel to the fixed part 6a, and a hole 7 is bored in the tip 6c, and a rubber plug is inserted into the hole 7.
Tsushiyu 9 is fitted.

The shaft portion 5a of the drive gear 5 passes through the rubber pusher 9 of the support leaf spring 6, and the tip portion 6c of the support leaf spring 6 can move up and down slightly along the shaft portion 5a. When the tip 6c moves upward, the rubber pusher 9 comes into contact with the tapered engagement portion 5c to stop the rotation of the drive gear 5 by frictional force, thereby stopping the tip 6c from rotating.
When c moves downward, the rubber pusher 9 and the engaging portion 5c are separated, so that no load is applied to the drive gear 5 and it rotates smoothly.

When a drive pulse is input to the step motor 1 and the rotor 3 rotates, magnetic flux flows through the stator 2, and the small piece 8 fixed to the support leaf spring 6 resists the spring force of the support leaf spring 6 due to magnetism. and is sucked into the stator 2. Therefore, the support plate spring 6 is attached to the stator 2
The rubber pusher 9 and the engaging portion 5c are separated from each other by moving to the side, and the load on the drive gear 5 is eliminated. Next, if no drive pulse is input, no magnetic flux is generated in the stator 2, and the support plate spring 6 returns to its original position due to its own springiness. Then, the spring force presses the rubber pusher 9 against the engaging portion 5c to prevent rotation of the drive gear 5.

Therefore, according to the present invention, the support plate spring moves up and down as drive pulses are input to the step motor, and when no drive pulses are input, the movement of the intermediate gear is instantly stopped. Therefore, even if there is a backlash in the wheel train, the stop position of the pointer can be kept constant, and wobbling of the pointer can be eliminated. Further, since a drive pulse to the step motor is used, no other control member is required, and the structure is simplified. Furthermore, since it is not necessary to strictly consider the moment of inertia of the pointer, restrictions on the design of the pointer are relaxed.

In the above embodiment, the shaft of the intermediate gear adjacent to the rotor pinion is passed through the support plate spring to stop its movement, but other gears in the gear train are stopped by the support plate spring. You can also do that.

[Brief explanation of the drawing]

Fig. 1 is a view of the vicinity of a step motor showing an embodiment of the present invention, A is a front view thereof, B is a plan view thereof, and Fig. 2 is an enlarged view of the support leaf spring used in Fig. 1. is its sectional view, and b is its plan view. 1...Step motor, 2...Stator, 4...
...Rotor pinion, 5...Intermediate gear, 5a...Shaft part,
5c...Engaging portion, 6...Support leaf spring, 7...Hole,
8...Small pieces. 〓〓〓〓〓

Claims (1)

[Scope of utility model registration request] A structure to prevent the hands of an electronic watch from wobbling, comprising a step motor serving as a driving source, an intermediate gear which meshes with the rotor pinion of the step motor and has a tapered engaging portion on its shaft, and a support leaf spring which has one end fixed to the stator of the step motor, a hole on the other end into which the shaft can be inserted to enable the hole to be brought into and out of engagement with the engaging portion, and a small piece of magnetic material provided in the middle.