JPS6315825B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small motor for a timepiece, and more particularly to an improvement in a small motor for a timepiece that converts an alternating electric signal serving as a time reference signal source into mechanical constant speed rotational motion.

Various small watch motors are used to convert time reference signals such as pulse waves obtained from AC commercial power sources with excellent frequency accuracy, crystal oscillators, and other vibration sources into mechanical rotation of the time indicator hands.
Widely used in high-precision analog display clocks. This type of small motor for watches is required to have low power consumption and good self-starting characteristics, but conventional small motors have not always been able to fully satisfy these demands.

The following improved conventional devices are known as devices that aim to improve the motor efficiency and self-starting performance of such conventional general devices.

FIG. 1 shows the main parts of a conventional improved small watch motor.
Six magnetized rotor poles 21, 22, 23, 24, 25 and 26 are provided on the outer peripheral side surface of the rotor 20 that drives the rotor 20. Each rotor pole is arranged opposite to the rotor center so as to be of different polarity,
That is, the rotor poles 21, 23 and 2 forming the north pole
Rotor poles 24, 26 and 22 forming a south pole are arranged opposite to the center of the rotor 5, and each of the six rotor poles has a pitch angle of 60 degrees.

On the other hand, eight stator poles are arranged around the rotor 20 with gaps in between, and these stator poles are
It is formed on a pair of stator pieces 30 and 40. The stator pieces 30 and 40 have a total of eight stator poles 31, 32, 33, 34 and 41, 42, 4.
3, 44, and each stator piece 30 and 4.
Some of the stator poles of No. 0 are arranged at non-uniform angles, and stator poles 31 and 32, 33 and 34, and 41
and 42, and the pitch angles of 43 and 44 are set to 0.5 times the rotor pole pitch angle, that is, 30 degrees,
Further, the pitch angles of the stator poles 32 and 33 and 42 and 43 are arranged at 1.5 times the pitch angle of the rotor poles, that is, a pitch angle of 90 degrees. In addition, in the figure, among the stator poles of both stator pieces 30 and 40, stator poles 31 are adjacent to each other and are opposite to each other with a stator gap 100 interposed therebetween.
and 44, and 34 and 41 are arranged with a pitch angle of 0.5 times the rotor pole pitch angle, that is, 30 degrees.

An excitation coil 50 is magnetically coupled to the stator consisting of both stator pieces 30 and 40. That is, both stator pieces 30 and 40 are screwed to the core 52 of the excitation coil 50 by screws 54 and 56. In addition, the core 52 and the stator piece 30,
40 can be positioned and fixed by a fixing method other than screw connection, for example, by sandwiching or other fixing means.

The excitation coil 50 is supplied with a square wave alternating electrical signal 102 obtained from a crystal oscillator or other oscillator as shown in FIG.
The alternating magnetic flux corresponding to the frequency of stator pieces 30,
40.

In Fig. 1, the number of rotor poles is set to 6, the total number of stator poles is set to 8, and the pitch angle of each stator pole is set to 0.5 or 1.5 times the rotor pole pitch angle. The poles are formed from a main pole and a complementary pole having different air gaps from the rotor pole. That is, as stator poles 32 and 34 of stator piece 30, stator poles 42 and 44 of stator piece 40 form stator main poles, whereas stator poles 31 and 33 of stator piece 30 and stator pole 41 of stator piece 40 form stator main poles. and 43 form a stator commutating pole which has a larger air gap with the rotor pole than the aforementioned main pole. Therefore, two main pole pairs 32, 42 and 34, 44 and two complementary pole pairs 31, 41 and 33, 43 are formed through the center of the rotor 20.

In each stator piece 30, 40 of this device,
It will be understood that the main pole is always placed in a more clockwise position than the counter pole.

FIG. 3 shows a support structure for the rotor and stator in FIG. 1. The rotor shaft 10 is rotatably fixed by a base plate 62 and a receiving plate 64, and the rotor 20 is fixed to a rotor pole holding plate 66 fixed to the rotor shaft 10. A rotor pinion 68 is fixed to the rotor shaft 10 and is meshed and connected to a well-known timepiece wheel train (not shown), so that the rotation of the rotor 20 is transmitted to the time pointer hand via the timepiece train. A damper 70 is further loosely connected to the rotor shaft 10, and when an impact or vibration is applied to the rotor 20 from the outside, the damper 70 absorbs the impact or vibration and supports the rotor 20.
This acts to reduce rotational speed fluctuations. Stator pieces 30 and 40 are arranged on the sides of the rotor 20, and the stator pieces 30 and 40 are formed of an integral plate made of permalloy or the like containing 45% nickel. Incidentally, the rotor 20 and the stator pieces 30, 40 can also be made of permalloy or stator pieces made of laminated electromagnetic soft iron thin plates.

This conventional device has the above configuration, and its operation will be explained below.

In FIG. 1, the dynamic magnetic center line of the stator in this device is indicated by Y and Z. In this device, the dynamic magnetic center line is the center line of electromagnetic force acting between the stator rotors when the alternating electric signal 102 is applied to the excitation coil 50 and alternating magnetic flux is generated in the stator, and the dynamic magnetic center line is the center line of electromagnetic force acting between the stator rotors when the alternating electric signal 102 is applied to the excitation coil 50 and an alternating magnetic flux is generated in the stator.
0.40 is defined as the center line of electromagnetic force adjacent to the stator gap 100. In this device, when the stator piece 30 becomes the S pole and the stator piece 40 becomes the N pole, the N pole 21 of the rotor 20 becomes the stator main pole 32 and the stator complementary pole 31 of the stator piece 30.
When the excitation coil 50 is excited with the opposite polarity, the N pole 21 of the rotor 20 becomes the S pole.The stator main pole 44 of the stator piece 40 and the stator It is electromagnetically attracted and held at a position facing the commutative pole 43. From the above, it will be understood that in FIG. 1, the dynamic magnetic center line of the stator is indicated by Y and Z as described above. The dynamic magnetic center lines Y and Z are the geometric center positions of the main pole 44 and the commutative pole 43 and the main pole 32 and the commutative pole 31, respectively, but the gaps between the commutative poles 31 and 43 relative to the rotor 20 are the same as the main pole 32, 44, the dynamic magnetic center lines Y and Z are set at positions slightly shifted clockwise from the geometric center line of the main pole and the counter pole.

The dynamic magnetic center line of the stator is determined as described above, and the stationary center position of the rotor 20 will now be explained.

FIG. 1 shows an alternating electrical signal 10 to an excitation coil 50.
2 is not applied, that is, the rotor 20 is in a stable stable position, and the center line of the rotor pole facing the stator gap 100 at this time is defined as the static center position of the rotor. As is clear from the above-described arrangement of the rotor poles and stator poles, the magnetic flux indicated by the arrow φ passes through the stator poles from the rotor poles, and in this state, the rotor is in a stationary and stable position. Therefore, in FIG. 1, the rotor N pole 2
1 and the center line of the rotor south pole 24, the static center position of the rotor is indicated by X. The stationary center position This angle of deviation occurs because it is located at a position further clockwise than the pole.

From the above, the stationary center position
(However, the deviation angle Q arises from the difference in the magnetic coupling force between the stator main pole and the commutator pole with respect to the rotor.) That is, the stationary center position X is located approximately at the center of the dynamic magnetic center lines Y and Z, and as a result, there is almost no imbalance in the self-starting driving force in the clockwise and counterclockwise directions when the rotor 20 self-starts to vibrate. removed.

The rest position of the rotor pole in the rotor rest state where the alternating electric signal 102 is not supplied to the excitation coil 50 will be explained in more detail. As mentioned above, the magnetic flux indicated by the arrow φ passes through the stator pole from the rotor pole, and as a result, the magnetic flux from the rotor N pole 21 is transferred to the magnetic flux formed by the stator commutative pole 31 and the stator main pole 32 of the stator piece 30. It reaches the other adjacent rotor south pole 22 through the magnetic path with the maximum resistance. Similarly, from the rotor N pole 23, a complementary pole 33, a main pole 34
to the rotor S pole 24 through a magnetic path consisting of the rotor N
Magnetic flux passes from the pole 25 to the rotor S pole 24 through a magnetic path consisting of the main pole 42 and the commutative pole 41, and from the rotor N pole 21 to the rotor S pole 26 through the magnetic path consisting of the main pole 44 and the commutative pole 43. penetrate. As described above, when the rotor is at rest, the rotor pole magnetic flux passes through the magnetic path with the minimum magnetic resistance, and the stable stable state shown in FIG. 1 is obtained. Therefore, it is understood that in this state, the adjacent rotor N and S poles are in positions facing the adjacent stator main poles and commutative poles. In this case, at a position where one rotor pole, for example, the N pole 21, faces the adjacent stator main pole 31 and commutative pole 32,
The magnetic flux of the pole 21 reaches the rotor S pole, for example, the rotor pole 24 or 26, through a magnetic path with high magnetic resistance consisting of the stator pieces 30 and 40.
Since the magnetic resistance in this case is significantly larger than the magnetic resistance shown in FIG. 1 described above, such a resting position is never taken, and the resting position shown in FIG. 1 is always obtained in the resting state.

When the alternating electric signal 102 is supplied to the excitation coil 50 in the rotor stationary state shown in FIG. 1, the stator pieces 30 and 40 are alternately excited to the NS pole, and the stator piece 30 is excited to the S pole. Then, the rotor 20 starts to vibrate in the clockwise direction, and when the stator piece 30 is excited to the north pole, the rotor 20 starts to vibrate in the counterclockwise direction. The driving force at this time is that the static center position X of the rotor 20 is located approximately at the center of the dynamic magnetic center lines Y and Z of the stator, so it receives a balanced driving force in both directions and quickly generates self-starting synchronous vibration. can be done. Therefore, since the self-starting in this device does not suffer from loss caused by the unbalance of the driving force at the stationary center position be able to.

Furthermore, in this device, due to the difference in the magnetic coupling force between the stator main pole and the counter pole with respect to the rotor, a slight difference is given to the effective driving force when the rotor self-starts, thereby making it easier to orient the self-starting rotation direction in a fixed direction. Can be done. That is, there is a deviation angle Q between the static center position X of the rotor 20 and the center line P of the dynamic magnetic center lines Y and Z of the stator, and when starting from this static position, there is a slight deviation in both directions. This results in a difference in effective driving force.
In FIG. 1, when the stator piece 30 is excited to the S pole, the rotor N pole 21 is driven clockwise. For example, when the stator piece 30 is rotated by 30 degrees, the stator main pole 32 and the subpole 31 are connected to the rotor pole 21. The attraction driving force generated between the stator's dynamic magnetic center line Z and the rotor pole 2
Since the rotor pole 21 is further on the drive side (clockwise) than the center position of the rotor pole 21, a clockwise driving force is applied to the rotor pole 21 at this time as well. On the other hand, when the stator piece 40 is excited to the S pole, the rotor N pole 21 is driven counterclockwise. For example, when the stator piece 40 rotates by 30 degrees, the attraction that occurs between the stator main pole 44 and the complementary pole 43 and the rotor pole 21 The driving force is generated when the dynamic magnetic center line Y of the stator is on the counter-driving side (clockwise) from the center position of the rotor pole 21.
Therefore, at this time, a clockwise drive blocking force is applied to the rotor pole 21. Therefore, a large effective driving force is always applied to the rotor in the clockwise direction, and as a result, a constant deviation is applied in the self-starting rotation direction when entering synchronous constant speed rotation, and the rotor 20 is In most cases, a synchronous constant speed rotation in the clockwise direction occurs, making it possible to obtain a constant rotation direction. Of course, in order to more reliably determine the rotational direction of the rotor 20, it is also possible to separately provide a known reverse rotation prevention device.

The vibration of the rotor 20 during self-starting can be regarded as a parametrically excited vibration. Therefore, by appropriately selecting the parameters of the parametric equation, the rotation angle θ of the rotor 20 grows with time, and this angle It is possible to shift to synchronous constant speed rotation when the temperature exceeds 30 degrees.

As is clear from the above description, according to this conventional device, since the stationary center position X of the rotor 20 is located approximately in the center of the dynamic magnetic center lines Y and Z of the stator, vibration occurs when the rotor starts automatically. Since the unbalance of the driving force in the direction, ie clockwise or counterclockwise, is eliminated and the electromagnetic force between the stator and rotor is effectively used for the vibration growth effect, a very rapid self-starting characteristic can be obtained. or,
The rotor 20 has six rotor poles, and the number of stator poles is selected accordingly, making it possible to significantly reduce the vibration angle before transitioning to synchronous constant speed rotation compared to conventional methods. , the angle is 30 degrees even when the number of rotor poles is 6 as shown in Figure 1, which can be reduced to 1/3 compared to 90 degrees in conventional general equipment. This can be done quickly.

In particular, as shown in FIG. 1, by forming the stator from main poles and counterpoles that have different magnetic coupling forces with the rotor, the rotor 20 is given a constant deviation in its rotational direction, and is unidirectional like a clock. A small motor that is extremely suitable for devices that require rotation can be obtained.

Furthermore, according to this device, the motor efficiency can be significantly improved.

However, in the improved conventional device described above, since the main pole and the counter pole are provided, the starting direction is biased in the rotational direction of the rotor, and a biased starting force acts in the rotational direction of the rotor. It rotates beyond the rotation angle corresponding to the alternating electric signal and vibrates irregularly so as to stabilize at the position corresponding to the alternating electric signal. Therefore, when the rotation of the rotor is transmitted to the second hand of the time display section via the deceleration mechanism, the second hand moves with irregular vibrations. This was inconvenient as an analog display clock.

FIG. 4 shows the waveform of the current flowing through the excitation coil 50 of the improved conventional device, together with the alternating electric signal 102. In the figure, the horizontal axis indicates time, the vertical axis indicates the value of the excitation current, and the alternating electrical signal 1
The frequency of 02 is 16Hz.

As is clear from FIG. 4, the current waveform flowing through the excitation coil 50 is irregular, and a reverse torque is generated at an irregular phase 102a of the alternating electric signal 102.
It is understood that the rotor 20 is swung back at irregular timing.

In order to prevent the irregular vibrations of the second hand that occur as described above, there are ways to increase the inertia of the rotor, or to bias the rotor in the opposite direction with a spring, etc., but none of these methods work as a whole. This results in a disadvantage that the motor torque and motor efficiency are reduced.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a small motor for a timepiece that has good motor efficiency and does not involve irregular vibrations in rotor rotation.

A rotor with a plurality of magnetized rotor poles provided on its outer periphery, a stator consisting of a stator piece having a plurality of stator poles arranged at intervals around the rotor, and an excitation coil that supplies alternating magnetic flux to the stator. and a magnetic coupling with the rotor along a certain deviation starting direction in order to shift the static center position of the rotor from the center of the magnetic center line of the stator and biasing the starting direction of the rotor in a certain deviation starting direction. at least one main pole/commuting pole pair arranged in order of a commutating pole having a weak force and a main pole having a strong magnetic coupling with the rotor;
The present invention is characterized in that a starting direction setting means is provided for setting a starting direction of the rotor in a direction opposite to the deviation starting direction.

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

A first preferred embodiment of the present invention is shown in FIGS. 5 and 6, and the same members as those in the previous figures are denoted by the same reference numerals and explanations thereof will be omitted.

The rotating direction of the rotor 20 in this embodiment is the same clockwise direction as in the conventional device described above, but each main pole 32, 34, 42, 44 and each subpole 3 in FIG.
1, 33, 41, and 43 are exchanged.
That is, in this embodiment, the main pole is always placed behind the counterpole in the clockwise direction, and the static center position X of the rotor 20 is further away from the center (P) of the magnetic center lines Y and Z of the stator. By being shifted clockwise, the starting direction of the rotor 20 is biased counterclockwise.

As mentioned above, the present invention is characterized by providing a starting direction setting means for rotating the rotor in a direction opposite to the deflection starting direction, and in this embodiment, the starting direction setting means rotates the rotor 20 counterclockwise. A reversal prevention mechanism is provided to prevent rotation. That is, as shown in FIG. 6, in this embodiment, a pin gear 72 is fitted and fixed to the rotor shaft 10, and a pin gear 72 is fitted into the rotary shaft which meshes with the gear 72 and is rotatably supported on the base of the watch. The fixed gear 76 constitutes a reverse rotation prevention mechanism, and in FIG.
The engagement with the teeth No. 6 prevents the rotor 20 from rotating in the counterclockwise direction.

In this embodiment, the counterclockwise rotation of the rotor 20 is prevented by the reverse rotation prevention mechanism, so the rotor 20 can only rotate clockwise.

The preferred first embodiment of the present invention has the above configuration, and its operation will be explained below.

When the alternating electric signal 102 is applied to the excitation coil 50, the stator pieces 30 and 40 are excited alternately to N and S poles, and when the stator piece 30 is excited to the S pole, the rotor 20 moves clockwise and the stator When the piece 30 is excited to the north pole, the rotor 20 starts vibrating counterclockwise. In this embodiment, the rotor 20
cannot be rotated counterclockwise due to the reverse rotation prevention mechanism shown in FIG. 6, so the rotation in the clockwise direction is started by the clockwise vibration.

In this embodiment, the starting direction of the rotor 20 is deviated counterclockwise by the main poles 32, 34, 42, 44 and the complementary poles 31, 33, 41, 43, so the rotor 20 is started at a predetermined timing. The rotor 20 rotates while being subjected to braking.
can rotate without vibration.

In FIG. 7, the waveform of the current flowing through the excitation coil 50 of this embodiment is shown together with the alternating electric signal 102, and the same reference numerals as in FIG. 4 are used in FIG.

As is clear from the figure, in this embodiment, the exciting coil 5
The current waveforms flowing through 0 are almost the same both positive and negative,
It can be seen that a reverse torque is generated in the rotor 20 from a certain phase 102b. That is, in this embodiment, since the reverse torque that causes the swing back can be applied to the rotor 20 at approximately constant timing, it is possible to provide the rotor 20 with smooth and stable rotation without vibration. Therefore, by transmitting the rotation of the rotor shaft 10 of this embodiment to the second hand via a predetermined speed reduction mechanism, the second hand can be rotated smoothly without vibration. Therefore, the device of the present invention does not require a mechanism for suppressing the vibration of the second hand, which was required in the conventional device, and there is no loss that occurs in this vibration suppressing device, so the overall motor efficiency is further improved.

A second preferred embodiment of the present invention is shown in FIG. 8, and the same members as those in the previous figures are denoted by the same members, and their explanations will be omitted.

In the first embodiment described above, it is not necessarily necessary to provide a main pole and a complementary pole for each pole of each stator piece 30, 40, but only one pair of opposing poles as in this embodiment, that is, It is sufficient to provide main poles 32, 42 and complementary poles 31, 41.

A third preferred embodiment of the present invention is shown in FIG. 9, and the same members as those in the previous figures are given the same reference numerals and their explanations will be omitted.

In the first embodiment described above, the difference in magnetic coupling force between the main pole and the commutative pole is obtained by the air gap difference with respect to the rotor, but by making the pole width of the main pole wider than the pole width of the commutator pole. It is possible to obtain a similar effect, and in this embodiment, the pole width of the main pole is set wider than the pole width of the commutating pole, so that the magnetic coupling with the rotor is tight.

A fourth preferred embodiment of the present invention is shown in FIG. 10, and the same members as those in the previous figures are given the same reference numerals and explanations will be omitted.

In this embodiment, the rotor 20 and the stator each have one pole.

In the present invention, it is sufficient that the stator pieces 30 and 40 are provided with main poles and complementary poles that give the rotor 20 a deflection starting direction. It is also possible to do so. In addition, in this embodiment, the gap between the main poles 32, 42 and the rotor pole is
The gap is set smaller than the gap between the rotor pole and the rotor pole.

As explained above, according to the present invention, it is possible to provide a small motor for a watch with no vibration in rotor rotation and excellent motor efficiency. It is extremely suitable for

[Brief explanation of the drawing]

Figure 1 shows the rotor of a conventional small watch motor.
2 is a waveform diagram of an alternating electric signal supplied to the excitation coil of the conventional device in FIG. 1. FIG. 3 is an explanatory diagram of the rotor support structure in the conventional device in FIG. 1. The figures are: FIG. 1 is an explanatory diagram of the current waveform flowing through the excitation coil of the conventional device; FIG. 5 is an explanatory diagram of the configuration of the rotor and stator of the first preferred embodiment of the present invention; and FIG. FIG. 7 is an explanatory diagram of the configuration of the reverse rotation prevention mechanism in the embodiment, FIG. 7 is an explanatory diagram of the current waveform flowing through the excitation coil of the first embodiment, and FIG. 8 is a diagram of the rotor and stator of the second preferred embodiment of the present invention. FIG. 9 is an explanatory diagram of the configuration of a rotor and stator according to a third preferred embodiment of the present invention, and FIG. 10 is an explanatory diagram of the configuration of a rotor and stator according to a fourth preferred embodiment of the present invention. This is an explanatory diagram. 20... Rotor, 21, 22, 23, 24, 2
5, 26... Rotor pole, 30, 40... Stator piece, 31, 33, 41, 43... Stator complementary pole,
32, 34, 42, 44...Stator main pole, 50
... Excitation coil, 72, 74 ... Gear, X ... Stationary center position of the rotor, Y, Z ... Dynamic magnetic center line of the stator.

Claims (1)

[Claims] 1. A rotor with a plurality of magnetized rotor poles provided on its outer periphery, a stator consisting of a stator piece having a plurality of stator poles arranged at intervals around the rotor, and excitation for supplying alternating magnetic flux to the stator. a coil, the rotor is connected to the rotor along the deflection starting direction in order to shift the static center position of the rotor from the center of the magnetic center line of the stator and bias the starting direction of the rotor in a certain deflection starting direction. At least one main pole/commuting pole pair arranged in the order of a commutating pole with a weak magnetic coupling force and a main pole with a strong magnetic coupling with the rotor, and an activation for setting the starting direction of the rotor in a direction opposite to the deflection starting direction. A small motor for a watch, characterized in that it is provided with a direction setting means.