JPS647356Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a wheel train structure for an analog display type electronic timepiece that uses a step motor to display the pointer.

[Conventional technology]

For a long time, watches were driven by a mainspring and displayed the time by a second hand that moved about 6 steps per second, so the movement of the second hand was quite continuous, and there was almost no irregularity in indication due to the accumulation of eccentricity of each gear or pinion. It was never a problem. However, in recent years, with the introduction of electronic clocks, it has become common knowledge that the second hand moves in steps every second, and this step movement in steps every second has even come to be seen as evidence of the high precision of electronic watches using crystal oscillators. Ta. However, on the other hand, the direction of the second hand indicated by the movement of the second hand every second and the 60 equal divisions on the dial are proof of high precision.
The deviation was quite large, and I began to doubt its high accuracy. This variation in the direction indicated by the second hand is thought to be due to dynamic factors and static factors.The dynamic factor is largely due to the moment of inertia of the second hand, and the static factor is the gear train. This is largely due to the accumulation of eccentricity of the gears and pinion. An index device that positions the seconds display shaft gear is used in some devices to eliminate the effects of the above factors at once, but the structure and adjustment are cumbersome and it is not actually used in all quartz watches. Therefore, to deal with dynamic factors, the material of the second hand is made of aluminum, which has a light specific gravity, and a second hand spring is used, and to deal with static factors, the eccentricity of gears and pinions in the gear train is reduced. This has resulted in considerable effects. However, when a two-pole step motor is used as an energy converter for an electric machine, and a gear with a small diameter of about 2,000mm is used for the seconds display shaft gear, it is necessary to install a large number of bodies, and the static factor increases. Not only has the fluctuation in the direction of the second hand caused by this movement become a major problem again, but the mechanism has also become more complex, forcing the clock to become larger.

That is, as shown in Fig. 1, a regular deceleration mechanism can be obtained by providing a car body 4 having a deceleration function in addition to the car body 3 and transmitting the rotational motion from the rotor to the seconds display car body 2. This is what we are trying to do. In the case of such a gear train, the maximum possible angle α ₁ of the amount of variation in the pointing direction of the second hand is approximately expressed by the following equation.

α ₁ = 2×sin ^-1 1/R ₂ [(E ₂ + e ₄ ) + r ₄ /R ₄ {(E ₄ + e ₃ ) + r ₃ /R ₃ (E ₃ + e ₁ )}] However, R ₂ is seconds Display gear radius of car body 2, r ₃ is car body 3 pinion radius, R ₃ is car body 3 gear radius, r ₄ is car body 4 pinion radius, R ₄ is car body 4 gear radius, e ₁ is rotor 1 pinion radius. Eccentricity, E ₂ is the gear eccentricity of seconds display car body 2, e ₃ is the eccentricity of the car body 3, E ₃ is the car body 3.
E 4 is the gear eccentricity of the vehicle body 4, e ₄ is the gear eccentricity of the vehicle body 4, and E ₄ is the gear eccentricity of the vehicle body 4.

Similarly, in FIG. 2, an idler body 6 having no deceleration function is provided in addition to the body 5, and the rotational motion from the rotor 1 is transmitted to the seconds display body 2, thereby obtaining a regular deceleration mechanism. In the case of such a gear train, the maximum possible angle α ₂ of the amount of variation in the pointing direction of the second hand due to static factors is approximately expressed by the following equation.

α ₂ = 2×sin ^-1 1/R ₂ {E ₂ +kE ₆ +e ₅ +r ₅ /R ₅ (E ₅ +e ₁ )} However, R ₂ is the gear radius of the second display car body 2, and r ₅ is the gear radius of the car body 5. The pinion radius, R ₅ is the radius of the gear on the car body 5, e ₁ is the eccentricity of the pinion on the rotor 1, E ₂ is the eccentricity of the gear on the seconds display car body 2, e ₅ is the eccentricity of the pinion on the car body 5, E ₆ is the eccentricity of the car body 6 The gear eccentricity, k, is determined by the angle formed by the vehicle bodies 2, 6, and 5, and generally takes a value of 1 to 2.

[Problem that the invention attempts to solve]

However, if we assume that the gear eccentricity can be machined with an accuracy of 7μ and the pinion eccentricity with an accuracy of 3μ, then r ₄ /R ₄ is the minimum design value for the gear train shown in Figure 1.
It is considered to be about 0.5, and r ₃ /R ₃ is about 0.3, so α ₁ = 2 × sin ^-1 1/R ₂ [(7 + 3) + 0.5 {(7 + 3) + 0.3 (7 + 3)}] = 2×sin ^-1 (16.5/R ₂ ) If R ₂ = 1000μ, then α ₁ = 2×sin ^-1 0.01155 = 1.89° Since 1 second corresponds to 6°, α ₁ corresponds to 0.32 seconds, and ideally the needle Even if this is done, there will be a lead or lag of ±0.16 seconds at the maximum position.

In the case of the gear train shown in FIG. 2, even if k=1, α ₁ <α ₂ and the second hand indication deviation becomes large. Furthermore, if a large number of vehicle bodies or an extra idler vehicle body is provided, the wheel train mechanism not only becomes complicated, but also has the disadvantage that the construction becomes large.

The first purpose of this invention is to increase the diameter of the seconds display gear.
The object of the present invention is to provide a wheel train structure that reduces the amount of variation in the indicated direction of the second hand due to static factors in an electronic watch that displays analog information by step movement performed at a cycle of 1 second or more, even if the diameter is about 2000 μφ.
The second purpose is to achieve miniaturization of the watch.

[Means for solving problems]

In order to achieve the above purpose, the present invention has a hour wheel and two
The number wheel and the seconds display wheel are provided on the same axis, and the fifth gear is arranged above the first upper support plate that pivotally supports the top of the seconds display wheel, and the outer diameter of the fifth gear is It is constructed so that the second indicator wheel is located within the range of .

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 shows a sectional view of the essential parts of the first embodiment of the watch according to the present invention, in which the main plate 11 is connected to the center pipe 11.
a, Rotor lower support stone 11b, No. 5 car body lower support stone 11
c is locked, and has a hole 11d through which the third wheel body 18 passes. A first upper receiving plate 12 and a second upper receiving plate 13 are provided on the upper side of the main plate 11, and a lower receiving plate 14 is provided on the lower side.
are screwed (not shown). The first upper support plate 12 has a hole 12c into which the seconds display body upper jewel 12a and the third wheel body upper jewel 12b are engaged, and through which the fifth wheel body 16 passes. The second upper support plate 13 is engaged with a rotor upper support stone 13a and a fifth car body upper support stone 13b. The lower support plate 14 is locked with the third car body lower support stone 14a. The rotor 15 is an electric circuit (not shown)
The signal from the main plate 11 and the second upper receiving plate 13 is applied to the coil 15b, which rotates magnetically by half a rotation per second to move the second display body 17 in steps every second.
It is rotatably sandwiched between the rotor lower stone 11b and the rotor upper stone 13a. The fifth car body 16 meshes with the rotor 15, passes through the first upper support plate 12 with the hole 12c, and connects the fifth car body lower support stone 11c and the fifth car body upper support plate between the main plate 11 and the second upper support plate 13. It is rotatably held by the stone 13b. The seconds display wheel 17 meshes with the fifth wheel body 16, passes through the center pipe 11a, and passes through the center pipe 11a.
It is rotatably held between the main plate 11 and the first upper receiving plate 12 by the second display body upper receiving stone 12a. At this time, the second display vehicle body 17 is pressed against the second display vehicle upper jewel 12a by the second spring 21, thereby generating an appropriate slip torque. The third car body 18 meshes with the seconds display car body 17, penetrates the main plate 11 at the hole 11d, and has a third car body lower block stone 14a and a third car body upper block between the lower support plate 14 and the first upper support plate 12. It is rotatably held by the stone 12b. center pipe 11
A center wheel body 19 that meshes with the center wheel body 18 is loosely fitted to the center wheel body 18, and an hour wheel 20 is loosely fitted to the center wheel body 19, and the center wheel body 19 has a normal slip mechanism for time adjustment. The center wheel body 19 and the hour wheel 20 are respectively meshed with a sun wheel (not shown) in the same way as in a normal watch. The gear part 16a of the fifth wheel body 16 meshes with the gear part 17a of the second display body 17 and transmits rotational motion thereto, and the rotation axis of the second display body 17 is disposed within the outer diameter of the gear. The ratio of the radius R ₁₆ of the gear portion 16a of the fifth wheel body 16 to the radius r ₁₆ of the pinion portion 16b is made large, and at the same time, the design is made as compact as possible. Now, the gear part 17a of the seconds display body 17
R ₁₇ is the radius of R 17 , the eccentricity of the pinion part 15a of the rotor 15 is e ₁₅ , the eccentricity of the gear part 16a of the fifth wheel body 16 is E ₁₆ , the eccentricity of the pinion part 16b is e ₁₆ , the gear of the seconds display car body 17 If the eccentricity of the portion 17a is _E17 , then
In the case of the gear train shown in FIG. 3, the maximum possible angle α ₃ of the amount of variation in the pointing direction of the second hand due to static factors is approximately expressed by the following equation.

α ₃ = 2×sin ^-1 1/R ₁₇ {E ₁₇ + e ₁₆ + r ₁₆ /R ₁₆ (E ₁₆ + e ₁₅ )} Now, under the same conditions as in Fig. 1 (the eccentricity of the gear is 7μ,
α ₃ using eccentricity of kana (3μ, R ₁₇ 1000μ)
When calculating, r ₁₆ /R ₁₆ is about 0.2 to 0.16 due to design, so even if r ₁₆ /R ₁₆ is set to 0.2, α ₃ = 2 × sin ^-1 1/1000 {7 + 3 + 0.2 × (7 + 3)} = 2 × sin ^-1 12/1000 = 1.37°, and the amount of fluctuation is nearly 30% smaller than α ₁ .

[Effect of idea]

As mentioned above, by using the gear train of the present invention, it is possible to increase the diameter ratio of the gear and pinion of the fifth wheel body that transmits rotational motion to the seconds display body, so that from the rotor to the fifth wheel The cumulative effect of the eccentricity of the gear and pinion on the second hand can be greatly reduced. In addition, design difficulties tend to occur unless the distance between the rotor and the fifth wheel body (or fourth wheel body) that meshes with the rotor is large enough to a certain extent, but with the wheel train of the present invention, it is easy to achieve the desired center distance. Distance can be set. Furthermore, there is no need for an extra wheel train body, and even if the gear on the fifth wheel body is relatively large, the bottom of the seconds display body is placed within the outer diameter of the fifth wheel body, so the movement and eventually the watch can be made smaller. It is possible to achieve great effects, such as the ability to achieve

[Brief explanation of the drawing]

1 and 2 are sectional views of main parts showing a conventional wheel train structure, and FIG. 3 is a sectional view of main parts of a wheel train structure showing a first embodiment of the present invention. 11... Main plate, 12... First upper receiving plate, 13...
Second upper receiving plate, 14...lower receiving plate, 16...fifth car body, 16a...gear portion, 17...second display car body.

Claims (1)

[Scope of utility model registration request] The gear train structure of an analog display type electronic watch that uses a step motor to display the pointer includes an hour wheel to which the hour hand is attached, a second wheel to which the minute hand is attached, a second indicator wheel to which the second hand is attached, and a rotor pinion. A clock base that pivotally supports a rotor that constitutes a part, a fifth wheel consisting of a fifth gear and a fifth pinion for transmitting the rotation of the rotor to the seconds display wheel, and a lower part of the fifth wheel. a first upper support plate that pivotally supports the upper part of the second wheel; and a second upper support plate that pivotally supports the upper part of the fifth wheel; The number wheel and the seconds display wheel are provided coaxially, and the fifth gear is disposed above the first upper support plate, and the fifth gear is arranged so that the bottom of the seconds display wheel is in a plane. A wheel train structure for an electronic timepiece characterized by being configured so as to cover the entire surface of the vehicle.