JPS6346858Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a second wheel, which is a part of the structure of a wheel train mechanism, in a pointer display type wristwatch.

Miniaturizing the wheel train mechanism, which is one of the elements that make up a pointer display wristwatch, has long been a pressing need as we push forward with the miniaturization of watch movements in order to pursue the design of wristwatches. Ta. Generally, the gear train mechanism in a pointer display type wristwatch is often arranged from approximately the center of the watch movement toward the outer circumference of the watch movement, and other elements other than the gear train mechanism surround the gear train mechanism in a two-dimensional manner. Because of this arrangement, it was difficult to create a compact watch movement using a wheel train mechanism that was approximately the same size as before.

Therefore, one way to make watch movements more compact is to make the wheel train mechanism more compact.
Among this train mechanism, the second wheel is located almost in the center of the clock movement, and the pinion module is one of the largest among the train mechanisms.
Therefore, downsizing the second wheel can be said to be the most important factor in downsizing the wheel train mechanism.

FIG. 1 is a partial sectional view showing a part of the wheel train mechanism of a conventional two-hand plain timepiece using a second wheel.
In FIG. 1, reference numeral 1 denotes a base plate, and a flat member is used in order to reduce the cutting and machining process as much as possible to reduce the cost of the base plate. 3 is a bridge that supports the handle of the gear train. 4 is an hour hand, 5 is an hour wheel, and the hour hand 4 is attached to the tip of the hour wheel 5. 6 is a minute hand, 7 is a dial plate, and 8 is a needle washer having spring properties, which are interposed between the dial plate 7 and the flange portion of the hour wheel 5. 2 is a second wheel, the upper handle 2a is pivotally supported by the receiver 3 and regulates the radial direction, and the lower handle 2b is pivotally supported by the main plate 1 and also regulates the radial direction. The amount of lag in the axial direction of the second wheel & pinion 2 is regulated by the bridge 3 and the main plate 1. Further, the extension shaft 2c extending from the lower handle 2b has a tip end 2e.
A minute hand 6 is attached to the engaging portion 2d, and an hour wheel 5 is pivotally supported on the engaging portion 2d. And the upper surface 5 on the flange side of the hour wheel 5
a is in contact with the lower surface 2f of the lower handle 2b of the second wheel 2, and the spring force of the dial washer 8 applied by the dial 7 pushes up the second wheel 2 in the direction of the receiver 3 via the hour wheel 5. . Also, the bottom surface of the second pinion is the main plate 1 when removing the needle.
It has the role of receiving the force when the needle is pulled out by coming into contact with it.

The third wheel 9 has the role of transmitting force from a rotor (not shown) forming the step motor to the second wheel 2. Further, mechanical transmission between the second wheel 2 and the hour wheel 5 is performed by a reverse wheel (not shown).

According to the above configuration, the second wheel 2 is always pressed against the bridge 3 with a constant force by the spring force of the hand washer 8 via the hour wheel 5, which is a problem peculiar to pointer display type watches. This has the advantage that it is possible to easily eliminate pointer errors caused by minute rotations due to mesh backlash. On the other hand, when looking at the second wheel 2 alone, the minute hand 6 is attached to the tip 2e, so in order to secure the fixing force with the minute hand 6, a certain diameter (generally
500 to 700μ〓) is required, so the lower handle 2b cannot be made thinner than that diameter. Further, the lower handle 2b, which is the part that engages with the main plate 1, must be thinner than the diameter of the bottom of the second pinion. This is because if it is larger than the diameter of the tooth bottom of the pinion, a tooth profile will remain on the lower handle 2b, and the second wheel
This is because when the shaft rotates, it rubs against the shaft hole of the base plate 1, causing chips to be generated and causing jamming, or causing the shaft hole to become larger in diameter and deteriorating performance. For this reason, the conventional second wheel, even though gear cutting technology has progressed and it has become possible to cut pinion pinions with small modules.
Due to its structure, it was extremely difficult to miniaturize it.

The purpose of the present invention is to solve the above-mentioned problems and to downsize the clock movement by downsizing the second wheel.

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 2 is a partial sectional view of a two-hand plane timepiece using a second wheel and pinion according to an embodiment of the present invention. Second
In the figure, numeral 10 is the main plate, which is the lower substrate.In order to make the watch movement more compact and to realize low-priced watches that meet the needs of the market, thin flat plate members are used to reduce the number of man-hours in the machining process. It has been planned as much as possible. Reference numeral 11 indicates a gear train bridge which is an upper substrate, and 12 indicates a middle bridge. Both bridges are made of flat plate-like members in the same way as the base plate 10, in order to reduce costs. Reference numeral 13 denotes the third wheel, which is pivotally supported by the main plate 10 and the intermediate support 12, and mechanically transmits mechanical transmission from a rotor (not shown) constituting a step motor, which is an electromechanical converter, to the second wheel via a wheel train. Moves the minute hand for display. 15 is a minute hand, 16 is an hour hand, and 17 is an hour wheel, at the tip of which the hour hand 16 is attached. 18
is the hour wheel and performs mechanical transmission between the second wheel and hour wheel 17. 19 is a shaft seat, 20 is a dial plate, and 21 is a dial washer, which are mounted between the dial plate 20 and the flange portion of the hour wheel 17 as in FIG. 14 is a second wheel, its upper handle is pivotally supported by the train wheel bridge 11, and the minute hand 15 is attached to the tip 14e of the extension shaft 14c, as in FIG. 1. In order to ensure fixing force between the second wheel 14 and the minute hand 15 regardless of the size of the hand, its tip 14e needs to have approximately the same diameter as the conventional one. On the other hand, in the second wheel & pinion 14 shown in FIG. 2, the pinion part 14a is machined with a very small module, so the diameter of the bottom circle of the pinion part 14a is extremely small. For this reason, if the lower handle equivalent part 14b, which is the engagement part with the main plate 10, has the same diameter as the conventional one, a tooth shape will remain.
b was made smaller in diameter than the conventional one, and the shaft seat 19 was fitted and fixed. This shaft seat 19 is located at the second wheel & pinion 1 on the inner diameter of the hole.
4, and the outer diameter is formed in three steps. That is, the lower surface of the small diameter portion protrudes from the lower surface of the main plate 10 and is in contact with the upper surface of the flange portion side of the hour wheel 17 which is pivotally supported by the engaging portion 14d of the second wheel & pinion 14. The spring force of the dial washer 21 is transmitted to the second wheel & pinion 14, and the second wheel & pinion 14 is pressed against the train wheel bridge 11. Next, the middle part 1
9a is radially supported in the shaft hole of the main plate 10 and serves as a lower handle, and together with the upper handle, makes the second wheel & pinion 14 rotate smoothly. In addition, the large-diameter portion 19b maintains a clearance between its lower surface and the main plate 10 in the normal driving state of the watch, but when the watch is disassembled, its lower surface abuts against the main plate 10 and the force is applied when removing the needle. It is structured in such a way that it receives

As described above, by fitting and fixing the shaft seat to the part corresponding to the lower handle of the second wheel, the engagement with the shaft hole of the main plate,
Pressing the second wheel against the train bridge due to the spring force of the needle washer,
The function of receiving the force when removing the needle remains the same as before, and by making the pinion module smaller, the second wheel can be easily miniaturized.
Moreover, this occurs because the tooth root diameter has become smaller.
We were also able to eliminate the causes of performance deterioration and jamming, such as the generation of chips due to scratches with the main plate and the increase in the diameter of the shaft hole.

By implementing the present invention in this way, the wheel train mechanism could be easily miniaturized, and a significant effect on the miniaturization of watches could be achieved.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a wheel train of a conventional two-hand plain timepiece using a second wheel. FIG. 2 is a partial sectional view of a wheel train of a two-hand plain timepiece using a second wheel and pinion according to an embodiment of the present invention. 2, 14...2nd wheel, 2b, 14b...lower handle,
2c, 14c... extension shaft, 5, 17... hour wheel,
9,13...3rd wheel, 1,10...main plate, 8,2
1...Needle washer, 19...Shaft seat, 3, 11, 12...
Received.

Claims (1)

[Scope of utility model registration request] It has upper and lower substrates, a second wheel to which a minute hand is attached to a shaft passing through the lower substrate, and an hour wheel which is attached to the second wheel and to which an hour hand is attached, and the hour wheel is connected to the hour wheel by a springy hand washer. In the wristwatch having a structure in which the second wheel is pressed in the direction of the upper board through A second wheel structure for a wristwatch, characterized in that a shaft seat is fitted and fixed to a portion corresponding to the lower handle of the second wheel in order to press the wheel toward the upper substrate.