JPS628756B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a crystal watch equipped with an extremely simple speed reduction mechanism.

[Background Art] The applicant of the present application, who has been researching this type of timepiece, proposed one form thereof in Japanese Patent Application Laid-Open No. 50-3668 (Japanese Patent Publication No. 53-21665). The clock according to this proposal is
Since it was a three-hand watch, and the output shaft of the motor was parallel to each pointer axis, it required a considerable length in the direction of the pointer axis, and there was a limit to how thin the watch could be made. In addition, to meet the demand for a simpler two-hand watch that omitted the second hand, the second hand block and second hand wheel were removed, the motor rotation speed was slowed down, and its output gear was directly engaged with the minute hand wheel. would be possible.

On the other hand, it was discovered in 1973 that the output shaft of the motor was arranged perpendicular to each pointer shaft, and the second hand wheel of the crown gear was engaged with the output gear attached to this.
134982, also proposed by the applicant.

Therefore, if the former motor is arranged so that its output shaft is orthogonal to each pointer axis, and a crown gear is formed on the former minute hand wheel and this is meshed with the output gear of the motor, a two-hand watch can be created. could be realized.

However, in a two-hand watch that would be realized in this way, the meshing position of the crown gear of the minute hand wheel and the output gear of the motor is opposite to the case (main plate) with respect to the axis of the motor's output shaft. It becomes something by your side. When we examine this product as it moves into full-scale production, we find that there are problems that need to be improved in terms of its structure, ease of assembly, and workability of parts.

[Object of the Invention] The present invention was made in view of the above reasons, and its purpose is to provide a two-needle type that is simpler and thinner, and further improves ease of assembly and parts processing. offers crystal watches.

[Disclosure of the Invention] The crystal watch of the present invention includes a case that has a fixed gear on the surface side and a through hole inside the fixed gear, and a case that divides the frequency of a crystal oscillator and is synchronized with the frequency. The motor is driven every minute or every 30 seconds, and consists of a step motor that has an output gear attached to its output shaft and is located on the back of the case, and a step motor that has an output gear mounted on the back of the case. a minute hand block which has a pointer part and an eccentric cam located on the front side of the case, and whose shaft part passing through a through hole of the case is coaxially fixed to the minute hand wheel; In a crystal watch in which the hour hand block is disposed between the hour hand block and the minute hand block, the hour hand block is harmonically driven by the minute hand block. , the step motor is arranged so that its output shaft is orthogonal to each pointer shaft, and the minute hand wheel is formed into a crown gear, and the meshing position with the output gear is located at a position relative to the axis of the output gear. It is characterized by being placed on the side.

According to the present invention, as will be described in detail below, it is possible to provide a crystal watch that is simpler and thinner, and has improved ease of assembly and workability of parts.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

Reference numeral 6 denotes a case molded from synthetic resin, which consists of a disc-shaped base and a peripheral wall connected to the back side of the outer periphery of the base. The case 6 has an externally toothed fixed gear 6b having 11 teeth on its central surface side, and further has a through hole 6a inside the fixed gear 6b. Further, a time scale 6c is provided on the outer surface side of the case 6 so as to protrude over the entire circumference. Therefore, the front side of the case 6 also serves as a dial. 6d is a motor mounting portion provided on the back side of the case 6.

1 is a step motor that divides the frequency of a crystal oscillator and is driven every minute (or every 30 seconds) in synchronization with the frequency, and an output gear 2 is attached to its output shaft 1a.
A is attached. The step motor 1 includes a yoke 1b formed in a U-shape by an opposing piece and a connecting piece;
Iron core 1c magnetically coupled between opposing pieces, and iron core 1c
A coil 1d is wound around the outer circumference of the coil via a coil frame.
and an output shaft 1 protruding outward coaxially with the iron core 1c.
a, a permanent magnet rotor 2 having an output gear 2a and rotatably supported by an output shaft 1a. In the permanent magnet rotor 2, different poles are alternately magnetized in the circumferential direction on the side facing the opposing piece of the yoke 1b, and the opposing piece has inner magnetic pole teeth and outer magnetic pole teeth radially arranged in a manner corresponding to the number of poles of the permanent magnet rotor 2. The same number of magnets are formed alternately, and the permanent magnet rotor 2 rotates in response to the excitation of the coil 1d. This step motor 1 is disposed at a motor mounting portion 6d on the back surface of the case 6 so that its output shaft 1a is orthogonal to each pointer axis, which will be described later.

Reference numeral 3 denotes a minute wheel molded from synthetic resin, which is disposed on the back side of the case 6 and meshes with the output gear 2a.

The important point here is that the tooth portion 3a of the minute hand wheel 3 is formed into a crown gear, and the output gear 2
The meshing position with a is located on the case 6 side with respect to the axis of the output gear 2a.

The number of teeth of the crown gear is set so that the rotation of the output gear 2a is decelerated and the rotation of the minute hand 3 becomes 1/60 rpm.

4 is a minute hand block molded from synthetic resin,
On the front side of the case 6, a pointer part 4a, an eccentric cam 4b as shown in FIG.
d is coaxially fixed to the minute wheel 3. Note that this fixing may be done by press-fitting, caulking, etc., but in this embodiment, an elastic coupling method is used. Specifically, a rotation stop protrusion 3b is provided on the inner periphery of the hole of the minute wheel 3,
A slot 4 is provided at the tip of the shaft portion 4d of the minute hand block 4.
e, recess 4f that fits into protrusion 3b, and retaining portion 4;
g is provided. This minute hand block 4 can be shortened in axial length by making the meshing position of the minute hand wheel 3 with the output gear 2a as described above, thereby reducing the bending of the shaft portion, making it easier to achieve perpendicularity, and improving the workability of parts. It can be improved.

5 is an hour hand block molded from synthetic resin,
A cam driven portion 5 is disposed between the case 6 and the minute hand block 4, and is loosely fitted to the eccentric cam 4b and an internal tooth 5b having 12 teeth that meshes with the pointer portion 5a and the fixed gear 6b.
It has c. Therefore, hour hand block 5 is harmonically driven by minute hand block 4, and 1/12
Rotate at rph.

To assemble such a crystal watch, first, the internal teeth 5b of the hour hand block 5 are engaged with the fixed gear 6b of the case 6, and then the shaft portion 4d of the minute hand block 4 is fitted into the internal teeth 5b of the hour hand block 5 and the through hole 6a of the case 6. Then, the minute hand wheel 3 is mechanically and instantaneously elastically connected to the tip of the shaft portion 4d of the minute hand block 4 to be fixed. Thereafter, the step motor 1 is attached to the motor attachment portion 6d of the case 6 while the output gear 2a is properly meshed with the tooth portion 3a (crown gear) of the minute hand wheel 3.

In this assembly, the step motor 1 is attached after fixing the minute hand block 4 and the minute wheel 3.
The tooth portion 3a of the minute wheel 3 and the output gear 2a can be easily and appropriately meshed, the ease of assembly is greatly improved, and the risk of damage to the gear during assembly is extremely reduced.

To set the time, use the knob 4c of the minute hand block 4.
By rotating the output gear 2 of the step motor 1, the output gear 2 of the step motor 1 is forcibly rotated.

[Effects of the Invention] In the quartz watch of the present invention, the step motor is disposed so that its output shaft is orthogonal to each pointer axis, and the minute hand wheel has teeth formed as a crown gear, and a toothed portion of the minute hand wheel that is connected to the output gear. Since the meshing position is located on the case side with respect to the axis of the output gear, it can be made simpler and thinner, and it is easier to assemble mechanically such as press-fitting, caulking, or elastic coupling. The minute hand block and minute hand wheel can be instantly secured first, and then the step motor can be secured while properly meshing the output gear with the crown gear of the minute hand wheel, which improves assembly efficiency and prevents damage to the gear. There is less danger, and the length of the shaft of the minute hand block can be shortened, which reduces the bending of the shaft during plastic molding, makes it easier to achieve verticality, and improves the workability of parts. The practical effects will be significant, such as the amount used will be reduced.

[Brief explanation of the drawing]

FIG. 1 is a cutaway perspective view showing one embodiment of the present invention, FIG. 2 is a sectional view thereof, FIG. 3 is a plan view showing the meshing state of the internal teeth of the hour hand block and the fixed teeth of the case, and FIG. FIG. 4 is a perspective view of the minute hand block. 1...Step motor, 1a...Output shaft, 2...
...Permanent magnet rotor, 2a... Output gear, 3... Minute wheel, 3a... Teeth, 4... Minute hand block, 4a
... pointer section, 4b ... eccentric cam, 4d ... shaft section,
5... Hour hand block, 5a... Pointer section, 5b...
Internal tooth, 5c...Cam driven part, 6...Case, 6a
...Through hole, 6b...Fixed gear.

Claims (1)

[Claims] 1. A case that has a fixed gear on the surface side and has a through hole inside the fixed gear, and a case that divides the frequency of a crystal oscillator and synchronizes with the frequency every minute. or a step motor that is driven every 30 seconds and that is arranged on the back side of the case with an output gear attached to the output shaft, and a step motor that is arranged on the back side of the case and meshes with the output gear. a minute hand block in which a pointer part and an eccentric cam are located on the front side of the case, and a shaft part passing through a through hole of the case is coaxially fixed to the minute hand; the case and the minute hand; The hour hand block is disposed between the blocks and has a pointer part, an internal tooth that meshes with the fixed gear, and a cam driven part that fits loosely into the eccentric cam, and the hour hand block is connected to the minute hand block by a harmonic drive. In the quartz watch, the step motor is arranged such that its output shaft is orthogonal to each pointer axis, and the minute hand wheel
A quartz watch characterized in that the teeth are formed on a crown gear, and the meshing position with the output gear is located on the case side with respect to the axis of the output gear.