WO1998030939A1

WO1998030939A1 - Analog electronic clock

Info

Publication number: WO1998030939A1
Application number: PCT/JP1998/000033
Authority: WO
Inventors: Takanori Nanya; Kazuo Suzuki; Takayasu Machida; Shigeyuki Takahashi; Takeaki Shimanouchi
Original assignee: Citizen Watch Co. Ltd.
Priority date: 1997-01-08
Filing date: 1998-01-08
Publication date: 1998-07-16
Also published as: EP0950933A1; CN1243579A; JP3245181B2; EP0950933A4

Abstract

A weight (20) is added, to lessen moment as the whole rotary body, at least to a part of the rotary body including a hand (8) and train wheels (11, 2, 12, 3) for the rotation of the hand, in order to make a disturbance energy which a step motor (1) receives by an external impact, less than a small holding energy which the step motor (1) used in an analog electronic clock retains, or a thin part, a through hole, or a notch is formed at least in a part of said rotary body, or a part of the rotary members is formed by the combination of members with different specific gravities from each other. Transmission of the disturbance energy occurring at the hand part to the step motor (1) is prevented by providing a reverse transmission preventing gear at a part of said train wheels.

Description

Description Analog electronic watch Technical field

The present invention relates to an analog electronic timepiece that displays time using hands, and more particularly to a technique for further reducing power consumption and diversifying hands of an analog electronic timepiece. Background art

The time display method of a watch requires decorativeness in addition to accuracy, and analog display is superior in terms of display quality and high designability, and a method using a step motor for the actuator is required. Widespread.

FIG. 5 is a schematic perspective view showing how a force is transmitted from a stepping motor to a hand through a wheel train in a conventional analog electronic timepiece. In a normal three-hand watch, as shown in Fig. 5, the rotor 1a of the step motor 1, the fifth wheel 2, the fourth wheel 3, the third wheel 4, the second wheel 5, the minute wheel 6, The hour wheel 7 is sequentially connected via small gears 11 to 16. As a result, the second hand 8 integral with the fourth wheel 3 and the small gear 13, the minute hand 9 integral with the second wheel 5 and the small gear 15, and the hour hand 10 integral with the hour wheel 7 perform a predetermined hand movement. Do. Note that the second hand 8, the minute hand 9 and the hour hand 10 actually rotate coaxially with each other, but they are shown expanded for easy understanding.

The step motor 1 composed of the rotor la, the stator lb, and the coil lc is provided with a drive energy required to move the hands 8, 9, 10 and the hands 8, 9, 10 are subjected to external impact. Needs holding energy to prevent the needle jump phenomenon. Step motor 1 is designed so that these two energy values satisfy the clock specification. In the design of conventional step motors for timepieces, in order to meet the timepiece specifications, the required holding energy value is first set according to the guidelines used, and the design is made to satisfy this. The driving conditions are set appropriately within this range.

Therefore, as a result, the driving energy value itself is not optimized. On the contrary, if only the normal hand movement is performed, there is a possibility that the step movement can be performed with a smaller driving energy value than the current state.

Normally, a stepping motor always has retained energy in the form of a magnetic potential (resistance to moving from a stationary point), and only the portion of the input energy that exceeds this magnetic potential is the effective kinetic energy. Becomes Therefore, it is considered effective to reduce the holding energy value to reduce power consumption. As mentioned earlier, from the viewpoint of holding the hands, the holding energy value of the conventional analog electronic timepiece is reduced. It could not be made small enough.

The driving energy value here is not the total energy value generally given, but the effective energy value required when the pointer performs a non-stationary rotational motion at a fixed angle within a certain set time ( (Reduced energy value from total energy value). If there is no driving force exceeding this value, the intended rotational movement cannot be obtained. The holding energy value is the energy value required to hold the pointer so as not to cause the needle jump phenomenon in response to an external impact, and is a value uniquely determined from the specifications of the step motor.

In recent electronic watches, it has been pointed out that it is troublesome to replace the battery once every few years, and it is desired to eliminate the need for battery replacement. Measures to address this are to increase battery capacity and reduce power consumption. However, large batteries cannot be used due to restrictions on the outer diameter of a wristwatch. Furthermore, the electric motor conversion efficiency of the step motor itself is nearing its limit, and it is not possible to expect a drastic reduction in power consumption with conventional methods. In addition, in the conventional electronic timepiece, as described above, by setting a holding energy value larger than a disturbance energy value generated in the needle portion due to an external impact, it is attempted to prevent a needle jump phenomenon. Conversely, this means that the guideline cannot be held if the disturbance energy value exceeds the holding energy value.

The disturbance energy value indicating the magnitude of the external impact is calculated by calculating the moment of inertia (inertia) that takes into account the imbalance caused by the degree of unbalance with respect to the rotation axis of the moment of the rotating body including the pointer and the wheel train. Related to size.

Since the shape is almost set when the pointer is targeted, the disturbance energy value is greatly affected by the magnitude of the inertial moment, and if the needle shape is made larger or deformed with priority on design, the imbalance will occur. There is also a problem that the moment of inertia increases due to the increase of the inertia and the disturbance energy value easily exceeds the holding energy value. Under these circumstances, the major issue is how to further reduce the power consumption of electronic watches and realize a system that does not require battery replacement. In order to reduce the power consumption, it is necessary to reduce the above-mentioned retained energy value.

To solve this problem, it is necessary to remove the design constraints on the pointer and to maintain the freedom of zine while preventing the needle jump phenomenon even when the holding energy value of the step motor is small.

An object of the present invention is to solve these problems and reduce the above-mentioned holding energy value while satisfying the timepiece specification, thereby achieving further lower power consumption of the electronic timepiece.

In addition, the objective is to remove the restrictions imposed on the guidelines to prevent the needle jump phenomenon and to secure more design freedom. Disclosure of the invention

The present invention relates to a step motor having a pointer for displaying time, holding energy for holding the pointer when stationary, and generating one drive energy so as to exceed the holding energy at the time of hand operation, and a step motor for the step motor. In order to achieve the above object, an analog electronic timepiece having a wheel train for transmitting the movement of the hand to the hands is configured as follows.

Weights are added to at least a part of the rotating body including the pointer and wheel train that generate disturbance energy larger than the holding energy value of the step motor due to an external impact so as to reduce the moment as the whole rotating body. The disturbance energy value received by the step motor is set to be smaller than the front upper holding energy value.

Alternatively, a thin portion, a through hole, or a notch may be formed in at least a part of the rotating body so as to reduce the moment as the whole rotating body.

Furthermore, at least some of the rotating members of the rotating body may be formed of a combination of members having different specific gravities so as to reduce the moment of the rotating body as a whole.

In these analog electronic timepieces, the moment of the rotating body is represented by M, the pointer equivalent inertia moment from the finger to the step motor rotor via the wheel train is represented by I, and the watch undergoes a translational movement due to an external impact. When the speed at the time of performing is V and the holding energy of the step motor is Ep,

M ² / I <2 XE p / v ²

It is advisable to set the above M and I so as to satisfy the relationship.

Further, a reverse transmission preventing gear may be provided on a part of the wheel train with respect to the rotating body so that disturbance energy generated by an external impact is not transmitted to the step motor.

Here, the disturbance energy value is defined as the value of the pointer and the pointer when the external collision occurs. Is the amount of rotational energy generated in a rotating body consisting of gears, pinions and shafts, and is an amount related to the magnitude of the unbalance and the moment of inertia caused by the degree of unbalance of the moment possessed by the rotating body. is there. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic sectional view of a three-handed analog electronic timepiece for explaining an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a disturbance energy value generated in a second hand and a holding energy value of a step motor when two kinds of hammer tests are performed on each sample shown in Table 2.

FIG. 3 is an explanatory view of a normal rotation transmitting operation by a reverse transmission preventing gear provided in a part of a pointer rotating wheel train according to another embodiment of the present invention.

FIG. 4 is an explanatory view of the reverse transmission preventing operation.

FIG. 5 is a schematic perspective view showing a state in which torque is transmitted from a step motor to a hand via a wheel train in a conventional analog electronic timepiece. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view of a three-handed analog electronic timepiece for explaining an embodiment of the present invention. The basic components are the same as those of the conventional electronic timepiece shown in FIG. is there. Therefore, in FIG. 1, the same members as those in FIG. 5 are denoted by the same reference numerals. That is, focusing on the movement of the second hand 8, the rotor la of the step motor 1 and the fifth wheel 4 and the fourth wheel 3 are sequentially connected via the small gears 11 and 12, so that the fourth wheel The second hand 8 integrally connected by the wheel 3 and the second hand shaft 18 performs a hand movement operation. Here, the explanation of the third wheel 4 and thereafter is omitted, but the minute hand 9 and the hour hand 10 are also shown in FIG. It is the same as shown.

In FIG. 1, reference numeral 21 denotes a main plate, reference numeral 22 denotes a wheel train receiving plate, and reference numeral 23 denotes a dial plate. The car 2, the fourth wheel 3, the third wheel 4, the second wheel 5, and the minute wheel 6 (see Fig. 5) are supported. The hour wheel 7 is supported between the main plate 21 and a dial 23 provided on the upper side thereof, and rotatably fits outside the minute hand shaft 24 into which the second hand shaft 18 is rotatably inserted. Have been. When an external impact is applied to the electronic timepiece, the second hand 8 generates disturbance energy and tends to rotate, but the magnitude of the disturbance energy is caused by the degree of imbalance of the moment of the second hand 8 with respect to the second hand axis 18. And the magnitude of the moment of inertia (inertia) of the rotating body due to the second hand 8 and the wheel train from the rotor 1a of the step motor 1 to the fourth wheel 3 via the fifth wheel 2 via the fifth wheel 2 I do.

Therefore, in this embodiment, the counterbalance is achieved by adding 綞 20 having a certain mass to the short portion 8b opposite to the indicating portion 8a with respect to the second hand shaft 18 of the second hand 8. In this way, it is possible to reduce the amount of momentary imbalance of the second hand 8 with respect to the second hand axis 18 to reduce the moment of the whole rotating body, and as a result, to reduce the disturbance energy value generated in the rotating body. it can. Therefore, even if the holding energy value of the step motor 1 is set to be small, it becomes possible to make the disturbance energy value received by the step motor 1 smaller than the holding energy value. Therefore, first, in the conventional electronic timepiece as shown in Fig. 5, the generated energy was estimated by examining the movement status of each component of the hand movement mechanism accompanied by mechanical movement.

First, in the stepping motor 1 and the handwheel mechanism of the analog electronic watch composed of the train wheel from the fifth wheel & pinion 2 to the hour wheel 7 and the hands 8, 9, and 10, the rotation motion information of each component is converted to the rotation angle. Obtain as time information. Each component required for the angular acceleration derived from this By multiplying the elementary moment of inertia, the generated torque value at a certain time when each component was moving was measured.

Of these, the reduction ratio is large and the contribution to the driving energy is considered to be very small after the third wheel 4 and the second hand 8 from the rotor 1a of the step motor 1 through the fifth wheel 2 and the fourth wheel 3 thereafter. Attention is paid to the movement of each component connected up to.

From the relationship between the generated torque value and the rotation angle when each component was moving measured by the above method, the amount of drive energy when each component moved was calculated. Next, as a result of examining the correlation between the amount of driving energy at the first wheel la, the fifth wheel 2, the fourth wheel 3 and the second hand 8 and the moment of inertia of each, the idea of the "one-port equivalent inertia moment" was obtained. It was found that the use of satisfactorily explained the amount of energy distributed to each component.

The term "equivalent moment of inertia" used here means that, in a normal analog electronic timepiece, as described above, the step motor, wheel train and pointer are all linked to make a rotational movement. This is a concept used to estimate the motion of the entire rotation mechanism by adding a moment of inertia (inertia) taking into account the difference at one location. When viewed from the rotor, it is called "rotor equivalent inertia", and when viewed from the pointer, it is called "guideline equivalent inertia".

That is, the relationship between the entire configuration of the rotating mechanism and the rotor equivalent inertia moment of each component is expressed by the following mathematical formula.

J ^ Jr + J5 / 36 + (J4 + Js) / 900 (1)

Here, J represents the rotor equivalent moment of inertia of the entire rotating mechanism, and Jr, J5, J4, and Js represent the moments of inertia of the rotor, the fifth wheel, the fourth wheel, and the second hand, respectively. The denominator “36” of each term in this equation is the square of the reduction ratio of the fifth wheel to the rotor, and “900” is the square of the reduction ratio of the fourth wheel to the rotor. The value of the square of the reduction ratio for the third wheel after the third wheel with respect to the rotor further increases rapidly. It can be seen that the contribution of the third and subsequent vehicles to the value inertia moment is negligibly small. Here, as an example, considering the low power consumption of a watch with a male second hand, the driving energy of each component is described as in equation (1). I understand.

One is that the smaller the rotor equivalent moment of inertia J of the rotating mechanism as a whole, the smaller the total drive energy is. The other is the contribution rate of each component to the rotor equivalent moment of inertia J. It can be seen that the influence of the change in the moment of inertia J s of the pointer on the change in J is small.

In other words, focusing on the second hand drive, it is shown that if the drive energy value is equal to or greater than the set value, the component with the smallest rotor equivalent inertia moment J can reduce the total drive energy as much as possible.

Next, the holding energy values of various stepping motors were estimated. In the past, a weight was suspended from the second hand, and the holding torque was measured from the weight at which the second hand began to move, and the holding energy value was estimated based on this. However, accurate estimation was not possible with this method due to the effects of friction and the fit of the train wheel.

Therefore, using the same method as the above-mentioned measurement of the generated energy value, the rotation motion information of the step motor rotor during idle running (no load rotation) was obtained as the rotation angle time information. Based on this, the kinetic energy value of the rotor at the rotational position was calculated to obtain the rotation angle information of the retained energy value, and the retained energy value was estimated based on this.

Based on the results, the rotor, fifth wheel, and fourth wheel (which are omitted from the third wheel and later) are slightly smaller than the components of the pointer rotation mechanism designed for conventional male watches. The effect was confirmed after fabrication. Table 1 shows the values of the moment of inertia, drive energy, and retained energy of each component at this time, along with those of the conventional watch.

In this table E- 1 1, E - 1 2 , E- 1 3 are respectively ^{X 1 0 - 1 1, X} 1 0 - 1 2, X ^10-13 is meant. "-" Means the same as the left column.

The notation is the same in Tables 2 and 3 below.

Since the second hand is the same as the conventional one, as can be seen from Table 1, the value of the inertia moment Js of the second hand is the same, but the value of the rotor equivalent inertia moment J is higher for the newly manufactured electronic watch. The driving energy was considerably reduced, and the driving energy was 13.6 nJ (nanojoule), which was less than 1/3 of the conventional 4355 nJ.

In this way, as a result of combining the second hand with the same second hand as a component that is one size smaller than before and driving the second hand, it was possible to achieve almost the same hand movement as expected as expected.

In addition, the minute and hour hands were incorporated and the hands were moved, but there was no change in the hand movement compared to the conventional case.

In addition, the holding energy value of the step motor manufactured this time is 154 nJ (nanojoule), which is less than 1 22 compared to the conventional 334 nJ, and the rotor equivalent inertia moment J decreases. In conjunction with this, the input energy required to move the second hand one step has been greatly reduced from the conventional 1450 nJ to about 6300 nJ.

Therefore, it was shown that by using such a pointer rotating mechanism, it is possible to significantly reduce power consumption while achieving the same hand movement as in the past.

However, the retained energy value is 154 nJ, which is less than or equal to 12 compared to the conventional value of 334 nJ, so that the disturbance energy generated when the pointer is subjected to an external impact is left as it is. The needle jump phenomenon occurs because the pile cannot be completely piled up. As a countermeasure, in this embodiment, as shown in FIG. 1, a weight 20 is added to the short portion 8b of the second hand 8 so that the moment as a rotating body of the second hand 8 is reduced by a counter-balance method. I made it. Usually, the second hand of man lifting clock 2. has ^{1 X 1 0- 11 kg · πι} 2 about the moment of inertia, and 2. 7 X 1 0- ⁹ kg · πι about moments.

In the embodiment shown in FIG. 1, the weight 20 having a certain moment of inertia is installed on the short portion 8b of the second hand 8 as a counterbalance, so that the second hand shaft 18 The imbalance of the moment with respect to was corrected, the disturbance energy generated in the second hand was reduced, and it was confirmed whether the hand jumping phenomenon could be prevented.

At this time, a hammer test in accordance with ISO 1413 was performed, and the presence of the needle jump phenomenon was confirmed by actually applying an external impact to the electronic timepiece of each sample.

An electronic watch using a normal male second hand was designated as sample 1.On the other hand, the length of the short portion of the second hand was gradually increased, so that the moment correction rate was gradually increased. 2 to 8 were prepared. At this time, the moment of the second hand of each sample, its moment of inertia (inertia), each value of the pointer equivalent inertia moment, the correction rate of the moment for sample 1, and the hand as a result of the hammer test Table 2 shows the presence or absence of the jump phenomenon.

The hammer test I is for normal external impact energy (drop the hammer onto a sample from a height of 30 cm), and the hammer test Π is for external impact energy twice as large as the hammer test I (hammer is 60 times smaller). (drop on a sample from a height of cm). The hammer test is performed 10 times for each condition. As a result, X indicates that the needle jumps constantly, △ indicates that the needle jumps several times, and that the needle jumps at all. 〇 is entered in the column for each test in Table 2.

As is clear from Table 2, in sample 1 without counterbalance, even in hammer test I, the needle jump phenomenon cannot be completely suppressed. On the other hand, by adding a weight with inertia moment at the short hand of the second hand (in this example, increasing the length of the short hand), if the moment correction rate is increased to 7% or more, the external impact It was shown that the needle jump phenomenon could be reliably prevented.

Since the weight 20 to be added to the short portion of the second hand for obtaining such a counter balance can be small, it can be implemented without impairing the appearance of a conventional watch. The addition of the weight 20 slightly increases the value of the inertia moment J s of the second hand. However, as is clear from the equation (1), the rotor equivalent inertia model due to this is obtained. The effect on the one-ment J is negligible and the driving situation does not change.

Next, the magnitude of the disturbance energy generated in the second hand of Samples 1 to 8 shown in Table 2 due to an external impact was estimated, and the holding energy of the step motor in the newly manufactured electronic watch shown in Table 1 was estimated. : An attempt was made to compare with 154 nJ.

The following equation was derived by considering the mechanism of disturbance energy generated due to the degree of moment imbalance in the second hand during an external impact.

^{E = (v 2/2)} X (M 2 I) (2)

Here, E represents the disturbance energy value generated in the second hand, V represents the speed at which the watch performs a translational movement by receiving an external impact, M represents the moment of the second hand, and I represents the pointer equivalent inertia moment.

The pointer equivalent inertia moment I is the equivalent inertia moment of the entire rotating body including the wheel train for transmitting the rotational force between the step motor and the rotor viewed from the pointer, and is obtained by the following equation.

I = J 4 + J s + 25 · J 5 + 900 · J r (3) where J s, J 4, J 5, J r are the second hand, the fourth wheel, the fifth wheel, and The moment of inertia of the rotor, the numerical value “25” is the square of the speed ratio of the fifth wheel, as viewed from the second hand, and “9”.

0 0 J is the square of the rotor speed ratio as viewed from the second hand.

Next, the correlation between the holding energy of the step motor: Ep and the disturbance energy: E derived from Equation (2) is shown together with the results of the needle jump phenomenon by the hammer tests I and Π shown in Table 2. Figure 2 shows.

In Fig. 2, the circled black dots indicate the disturbance energy values for hammer test I shown in Table 2 and the squared black dots indicate the disturbance energy values for hammer test に shown in Table 2. The appended numbers are the sample numbers in Table 2. In addition, the holding energy Ep of the step motor is 15 times that of the newly manufactured electronic timepiece shown in Table 1.

The level at 4 nJ is indicated by a broken line. From the results in Table 2 and Figure 2,

^{E p> E = (v 2} /2) X (M 2 / I) (4)

It was found that the needle jump phenomenon could be prevented within the range satisfying the above. As is clear from the hammer test results in Table 2, there are areas where the results are judged to be △ depending on the conditions, so it is difficult to clearly define the validity range. (4) seems to be a guide.

Actually, the retained energy including the friction loss in the wheel train acts. Assuming that it is Eq, in the stepping motor and wheel train configuration used in this hammer test, as shown by the two-dot chain line in FIG. 2, Eqp + 100 nJ. Therefore, as in the test results shown in Table 2, in the case of Samples 2 to 8, the impact test I showed E and E q, and no needle jump occurred.

This is because the moment M of the second hand, the equivalent moment of inertia I of the pointer, the speed V at which the watch performs a translational movement due to an external impact, and the retained energy of the step motor Ep is correlated with each other, and at least within the range that satisfies Equation (4) (M ² ZI <2 XE p / v ² ), the guidelines are reliably maintained. It is shown that.

In the past, a hammer test was actually performed on a set step motor, and the use conditions for the guidelines could only be restricted in the form of the range of moments obtained from these results. By substituting each parameter value into Equation (4), the condition range to be satisfied by the guideline is determined in advance, and the maintenance of the guideline is achieved within this range.

In the above-described embodiment of the present invention, it has been clarified that the second hand can be maintained if the moment correction of the moment imbalance of the second hand is 7% or more.

On the other hand, in reality, since the design is given to the pointer, its moment of inertia and The moments and moments cannot be determined uniquely, but are distributed over a certain range. In this case, if the counter balance is performed assuming that the moment correction rate is the largest within the range that satisfies the formula (4), the same component can be used for the variation of the pointer. .

In the above-described embodiment, the weight 20 having the moment of inertia at the short portion 8b of the second hand 8 is added as a counterbalance (including making it longer or thicker). However, the same correspondence is applied to the fourth wheel & pinion 3, which constitutes the wheel train between the second hand 8 and the rotor 1a shown in FIG. It is also possible by adding a weight at a position corresponding to the short portion 8b of the second hand 8 with respect to the axis. As a result, it is possible to reduce the moment of the whole rotating body including the second hand 8 so that the disturbance energy value received by the step motor becomes smaller than the holding energy value.

Since the second hand 8, the fourth wheel & pinion 3, the small gear 13 and the second hand shaft 18 move in combination, it is possible to adjust the unbalance amount individually or in combination of a plurality of them. is there. In addition to adding a weight, the method of adjustment is to reduce the moment of the whole rotating body to at least a part of the rotating body composed of the second hand 8, the fourth wheel 3, the small gear 13 and the second hand shaft 18. It is also possible to form a thin-walled part, a through-hole, or a notch so as to make it thinner.

Alternatively, at least a part of the rotating member (such as a gear) of the rotating body may be formed by a combination of members having different specific gravities to reduce the moment as the whole rotating body.

Of course, in these cases, it is possible to make the resulting disturbance energy value, that is, the disturbance energy value received by the step motor smaller than the retained energy value.

Further, in the above embodiment, the second hand has been described as an example, but the same applies to the minute hand and the hour hand. The idea can be applied.

That is, if the pointer to be operated is known, the driving energy value derived from the operating condition of the pointer is estimated, and then the wheel is set so as to satisfy this value and to have the smallest possible roach equivalent inertia moment J. Design the components of the rotating body including the rows. As a result, counterbalance is performed so that the disturbance energy is smaller than the holding energy value of the step motor, so that the driving and holding of the hands can be satisfied to the same degree as in the case of the conventional watch specification, and Power consumption can be greatly reduced. In addition, when the present invention is applied to a female watch, it is possible to realize a watch that is smaller and consumes less power than before, and can also respond to diversifying designs.

Next, another embodiment of the present invention will be described with reference to FIGS. In this embodiment, although not specifically shown, a part imitating an airplane shape is provided near the tip of the second hand in order to represent the world map on the dial and to represent an image of an airplane turning on the dial. The attached second hand was produced. Table 3 shows the values of the moment of inertia and the holding energy of each component of the rotating body consisting of the second hand and the wheel train for rotating it at this time, together with those of the conventional man-held electronic timepiece.

The design applied to the second hand increased the moment of inertia J s of the second hand to about eight times that of the conventional man-held electronic watch, and there was concern about the effect on hand movement behavior. However, as can be estimated from Equation (1), the increase of the rotor equivalent inertia moment J is at most about 10 percent, and the actual movement is not so much changed. Thus, there was almost no change in the input energy value.

From another experiment, it was confirmed that in the stepping motor used here, it was possible to move the hand without much change in the movement until the increase of the rotor equivalent inertia moment J was about 100%. I have.

Mode one instrument 1 having the second hand in this embodiment ^{8 X 1 0 -. 8 kg} 'm about the Do Ri, 2 conventional man lifting hand has ^{7 X 1 0 -. 9 kg} ' than the m 7 About twice as large Has become. If this state is left as it is, as described in the above-described embodiment, the needle jump phenomenon of the pointer will occur even for an external impact of the same level as in the related art.

To prevent this, in this embodiment, the second hand and the step motor

-A reverse transmission prevention gear is provided on a part of the gear train that constitutes the train

-Is not transmitted to the step motor.

FIGS. 3 and 4 show the wheel train configuration of the analog three-hand electronic timepiece, which shows the pinion 31 that constitutes the wheel train between the second hand and the rotor of the step motor (the small gears 11 and 1 in FIG. 5). 2) and gear 3 2 (corresponding to fifth wheel 2 or fourth wheel 3 in FIG. 5) to explain the operation when at least one of the reverse transmission prevention gears is used. FIG.

Normally, as shown in FIG. 3, the force is transmitted by the rotation of the pinion 31 in the direction of arrow A, and the gear 32 rotates in the direction of arrow B. This relationship continues from the rotor to the fifth wheel, the fourth wheel, the third wheel, and so on, so that power is transmitted efficiently.

On the other hand, when an external impact is applied to the main body of the watch, a rotational force caused by disturbance energy generated in the second hand acts on the gear 32, and attempts to transmit this force to the pinion 31. Here, as shown in Fig. 4, the kana 31 and the gear 3 2 mesh at points a and b, and cannot rotate because they stick together. Therefore, the rotational force in the direction indicated by the arrow C of the gear 32, which is the opposite direction to the normal force transmission, is not transmitted to the pinion 31.

When holding the second hand, a reverse transmission prevention gear should be used in at least one of the pinion and fifth gear of the rotor and the pinion and fourth gear of the fifth wheel. FIG. 4 illustrates the case where the gear 32 is about to rotate leftward due to an external impact. However, the transmission of force is similarly prevented when the gear 32 is about to rotate rightward.

By using this mechanism, it is possible to prevent the needle jump phenomenon even in a situation where the held energy value of the step motor is smaller than the disturbance energy value. Therefore, it has a large moment of inertia and moment compared to conventional W

16 Even with the use of the hands, the driving and holding of the hands can be satisfied to the same extent as the conventional clock specification, as in the above-described embodiment. This effect was confirmed by performing a hammer test in accordance with ISO 1413 on the completed watch with the hour, minute and second hands.

In addition, the rotational energy may be applied to the watch due to an external impact in addition to the above-mentioned translational energy. For this purpose, a so-called flutter test is performed to confirm that there is no inconvenience. I have.

Here, the fluttering test is a test method that takes into account the rotational shock generated by placing the watch body in an arbitrary direction in an empty box and free-falling it from a predetermined height. It must not be.

Under normal operating conditions, the watch body is not subjected to such a large rotational impact, so it is considered that there is no problem if the hammer test is passed.

In the two embodiments described above, the effects of the counterbalance and the reverse transmission prevention gear by adding a weight and the like have been described. However, further effects can be obtained by using these two mechanisms together.

In other words, in the area where the external impact is small, the disturbance energy value generated at the finger portion by the counter-balance mechanism is very small, and the force for displacing the wheel train is not generated. In addition, against a large external impact that cannot be maintained by the counterbalance alone, the reverse transmission prevention gear mechanism prevents the reverse transmission of force.

However, at this time, since the disturbance energy value was greatly reduced by the counter balance, the force acting on the strut (point b) between the gear 32 and the pinion 31 shown in FIG. There is no need to worry about deterioration of the shape of the part.

As a result, even if a step motor having a small holding energy is used, the pointer can be reliably held with high reliability against a wide range of impacts. In the present invention, it has been confirmed that the power consumption can be sufficiently reduced compared to the conventional case even in the contents shown in Table 1.However, improvement of efficiency and optimization of the component It is possible to further reduce power consumption by further reducing the inertia moment by reducing the size of the device or by using plastic, and by reducing the hand-handling conditions.

In addition, any mechanism other than the counter-balance can be used as long as the mechanism can reduce the magnitude of the external impact to a disturbance energy smaller than the retained energy value. For example, an external shock may be absorbed in the middle by a shock absorbing material arranged around the module, or the disturbance energy value itself may be reduced by the pointer shape and material. Further, the components may be mechanically fixed against an external impact, and a structure may be employed in which the locking mechanism operates only when an external impact is detected.

Further, in the embodiment of the present invention, the case of a wristwatch using a step motor as an actuator has been described, but the present invention is of course applicable to a mouthpiece. Rather, in the case of a clock, the external impact is not as much of a problem as in a wristwatch, so the holding torque value may be smaller. Estimating the driving energy value required for needle movement and reducing the rotor equivalent inertia moment J within this range will make it possible to significantly reduce power consumption.

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Table 1

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• CE rice W¾f? Ea na BT

Electronic timepiece Drive energy (n J) 435 1 36 Retention energy ( _n J) 334 1 54

J (kg · m ² ) 1.3 E—12 2.3 E—1 3

1. 1 E— 1 2 1. 6 E— 13

J 5 (kg 'm ² ) 6.4 E— 1 2 1.9 E— 1 2

J 4 (kg · m ² ) 8.0 E— 1 23.5 E— 12

J s (kg · m ² ) 2.1 E—11 Input energy (n J) 1450 630

Table 2 Sample No 1 2 3 4 5 6 7 8 Moment 2.7E-9 2.5E-9 2.3E-9 1.9E-9 1.6E-9 1.1E- 5.9E-10, 1.6E-11 ( ■ kg · m)

Second hand moment of inertia 2.1E-11 2.2E-11 2.3E-11 2.4E-11 2.6E-11 2.8E-H 3.0E-11 (kg-m

Pointer equivalent inertia moment 2.0E-10 2.1E-10

(kg · m "

0 7 17 29 43 60 78 99.4 Moment correction factor for sample 1

(%)

Nommer test I Δ 〇

Nommer test Π X Δ 〇

Table 3

Industrial applicability

According to the present invention, the equivalent inertia moment of the whole rotating body including the hands and the wheel train for rotating the hands is reduced within a range that satisfies the driving energy value required for the hands movement in the timepiece. Then, the disturbance energy generated in the pointer due to the external impact is reduced to a value smaller than the reduced holding energy value.

As a result, drastically lower power consumption can be achieved while maintaining the same driving and holding performance as before, and a system that does not require battery replacement can be realized.

Alternatively, when using the same level of power as before, the same driving and holding performance as before can be ensured even if a pointer with a moment of inertia that is at least 10 times larger is used than before. it can. For this reason, it is possible to add design function elements to the pointer, which could not be achieved under the conventional constraint conditions, and the degree of freedom is greatly expanded.

Claims

The scope of the claims

1. A step motor that has a pointer for displaying time and holding energy for holding the pointer when stationary, and generates driving energy so as to exceed the holding energy during hand operation, and the movement of the step motor. And a wheel train for transmitting to the hands,

At least a part of the rotating body including the pointer and the train wheel which generates a disturbance energy larger than the holding energy value of the step motor due to an external impact is provided with a weight so as to reduce the moment as the whole rotating body. In addition, the disturbing energy value received by the step motor is made smaller than the retained energy value.

2. A step motor having a pointer for displaying time, and holding energy for holding the pointer when stationary, and generating driving energy so as to exceed the holding energy during hand operation, and movement of the step motor. And a wheel train for transmitting to the hands,

At least a part of the rotating body including the pointer and the wheel train, which generates a disturbance energy larger than the retained energy value of the step motor due to an external impact, includes a thin-walled portion, so as to reduce the moment as the whole rotating body. An analog electronic timepiece, wherein a through hole or a notch is formed, and a disturbance energy value received by the step motor is smaller than the holding energy value.

3. A step motor that has a pointer for displaying time, a holding energy for holding the pointer when stationary, and generates driving energy to exceed the holding energy at the time of hand operation, and a movement of the step motor. And a wheel train for transmitting to the hands, At least some of the rotating members, including the hands and the train wheel, that generate disturbance energy greater than the retained energy value of the step motor due to an external impact, so as to reduce the moment of the rotating body as a whole. An analog electronic timepiece formed of a combination of members having different specific gravities, wherein a disturbance energy value received by the step motor is smaller than the holding energy value.

4. In the analog electronic timepiece according to claim 1,

The moment of the rotating body is M, the equivalent moment of inertia of the pointer from the pointer to the rotor of the step motor via the train wheel is I, and the speed at which the watch performs translational movement by receiving an external impact. v, the holding energy of the step motor when a ^{E p, M 2 Z l <} 2 XE p / v 2

An analog electronic timepiece, wherein M and I are set so as to satisfy the following relationship.

5. The analog electronic timepiece according to claim 2,

M is the moment of the rotating body, I is the pointer equivalent inertia moment from the pointer to the step motor rotor via the train wheel, and I is the speed at which the watch performs translational movement by receiving an external impact. v, when the holding energy of the step motor is Ep, M ² ZI and 2 XE p Z v ²

6. The analog electronic timepiece according to claim 3,

The moment of the rotating body is M, the equivalent moment of inertia of the pointer from the pointer through the train wheel to the rotor of the step motor is I, and the speed at which the watch performs translational movement under external impact is v, the holding energy of the step motor is Ep Was at the ^{time, M 2 / I <2 XE} p / v 2

7. A step motor that has a pointer for displaying time, holding energy for holding the pointer when stationary, and generates driving energy so as to exceed the holding energy during hand operation, and movement of the step motor. And a wheel train for transmitting to the hands,

For a rotating body including the hands and the wheel train that generates a disturbance energy larger than the holding energy value of the step motor due to an external impact, a reverse transmission prevention gear is provided in a part of the wheel train, and the disturbance energy is provided. Is not transmitted to the stepping motor.