JP2003189586A - Stepping motor and electronic timepiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a power consumption by increasing a cogging torque in a state in which a coil is not excited and decreasing the torque in a state in which the coil is excited. <P>SOLUTION: When the coil 109 is excited, first saturable parts 116, 117 are magnetically saturated so that a magnetoresistance is increased. A region 120 in which a through hole 114 and the region 116 are gathered and a region 121 in which a through hole 115 and the region 117 are gathered are functioned as an inner notch having a larger area than those of inner notches 104, 105, and a rotary drive with a low energy can be conducted. Then, saturable regions 110, 111 are saturated so that the rotor 102 is rotated in a direction of an arrow B at 180°. When the exciting of the coil 109 is stopped, the parts 116, 117 are not magnetically saturated so that the rotor 102 is stably stopped at a position where its magnetic axis A intersects perpendicularly the line segment connecting the inner notches 104, 105. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor and an electronic timepiece using the stepping motor.

[0002]

2. Description of the Related Art Conventionally, a stator having a rotor accommodating hole and a positioning portion for determining a stop position of the rotor, a rotor arranged in the rotor accommodating hole, and a coil are provided.
A stepping motor is used which supplies an alternating signal to the coil to generate a magnetic flux in the stator to rotate the rotor and stop the rotor at a position corresponding to the positioning portion.

FIG. 4 is a block diagram of a stepping motor conventionally used in an electronic timepiece. In FIG.
The stepping motor is integrated with the stator 301 by a stator 301 having a rotor accommodating hole 303, a rotor 302 rotatably accommodated in the rotor accommodating hole 303 and having two poles (S pole and N pole) magnetized, and screws 312, 313. And a coil 309 wound around the magnetic core 308.

The stator 301 has a rotor housing hole 303.
Two recesses (outer notches) 30 at opposite positions across
6, 307 are provided and outer notches 306, 307
And the rotor housing hole 303 between the saturable portions 310 and 311.
Are formed. Further, the stator 301 has two positioning recesses (inner notches) continuous with the rotor housing hole 303 and facing each other with the rotor housing hole 303 interposed therebetween.
304 and 305 are provided.

When the coil 309 is not excited, the rotor 302 has its magnetic pole axis A whose inner notch 304,
It is stably stopped at a position orthogonal to the line segment connecting 305. To rotate the rotor 302, FIG.
As shown in the characteristic diagram of the stepping motor in (a), the energy is applied so as to overcome the maximum point D of the magnetic energy. In addition, in FIG.
As shown in, the position where the line segment connecting the inner notches 304 and 305 is orthogonal to the magnetic pole axis A of the rotor 302 is the rotation angle of the rotor 302 of 0 degree.

Now, a rectangular pulse signal is sent to the coil 309.
To the electric current i in the direction of the arrow in FIG.
A magnetic flux of magnetic energy is generated in the stator 301 in the direction of arrow C so as to get over the maximum point D. This allows
The saturable portions 310 and 311 are saturated first to have a high magnetic resistance, and then the magnetic poles generated in the stator 301 and the rotor 30.
Due to the interaction with the two magnetic poles, the rotor 302 rotates 180 degrees in the direction of arrow B in FIG. 4 and stops stably.

Next, when a pulse signal of a rectangular wave of opposite polarity is supplied to the coil 309 and a current is passed in the direction opposite to the arrow shown in FIG. 4, the stator 301 is moved in the direction opposite to the arrow C so as to cross the maximum point D. Magnetic flux of various magnetic energy is generated. As a result, the saturable units 310 and 311 are saturated first, and then,
Due to the interaction between the magnetic poles of the stator 301 and the magnetic poles of the rotor 302, the rotor 302 rotates 180 degrees in the direction of arrow B in FIG. 4 and stops stably. After that, by supplying signals having different polarities (alternating signals) to the coil 309 in this manner, the above-described operation is repeated and the rotor 302 can be continuously rotated by 180 degrees in the direction of arrow B. it can.

[0008]

By the way, the coil 30
9 is not excited, the inner notches 304, 30
Due to the cogging torque (stationary torque) generated by No. 5, the magnetic pole axis A of the rotor 302 has an inner notch 304,
It is regulated to stably stop at a position orthogonal to the line segment connecting 305.

For example, in the case of a stepping motor for an electronic timepiece, the magnitude of the cogging torque is set to a certain magnitude in order to prevent the pointers (time hands such as the second hand and the minute hand) from being displaced due to disturbance or drop impact. If it is necessary and the pointer is increased, the cogging torque also needs to be increased. In addition, the power consumption for rotating the rotor 302 also depends on the cogging torque, and if the cogging torque is large, the power consumption also increases. Therefore, when attempting to rotationally drive a large pointer, the cogging torque also has to be increased, which causes a problem that power consumption also increases.

The present invention has been made in view of the above problems, and the power consumption can be reduced by increasing the cogging torque when the coil is not excited and by decreasing the cogging torque when the coil is excited. It is an object to provide a stepping motor configured as above. Further, according to the present invention, the cogging torque is increased when the coil is not excited, and the cogging torque is decreased when the coil is excited, so that the power consumption can be reduced. An object of the present invention is to provide an electronic timepiece capable of rotationally driving the time hand.

[0011]

According to the present invention, there is provided a stator having a rotor accommodating hole and a positioning portion for determining a stop position of the rotor, a rotor disposed in the rotor accommodating hole, and a coil. A stepping motor configured to rotate the rotor by supplying an alternating signal to the coil to generate a magnetic flux in the stator and stop the rotor at a position corresponding to the positioning portion, A through hole formed at a first saturable portion having a first predetermined length from an end of the first saturable portion, the first saturable portion being provided to the stator by an alternating signal supplied to the coil. The area of the through hole and the first saturable portion corresponding to the through hole that is magnetically saturated by the generated magnetic flux is larger than the area of the positioning portion. Stepping motor is provided. The first saturable portion is magnetically saturated by the magnetic flux generated in the stator by the alternating signal supplied to the coil, and the total area of the through hole and the first saturable portion corresponding to the through hole is equal to that of the positioning portion. It is larger than the area and is driven to rotate with low power consumption.

Here, a plurality of through holes may be provided at positions facing each other with the rotor accommodating hole sandwiched therebetween. Further, a plurality of the positioning portions may be provided at positions facing each other with the rotor accommodating hole sandwiched therebetween. A plurality of the positioning portions are provided at positions facing each other with the rotor housing hole interposed therebetween, and a plurality of through holes are provided at positions facing each other with the rotor housing hole sandwiched therebetween. Alternatively, the line segment connecting the above-mentioned and the line segment connecting the plurality of through holes may be orthogonal to each other. The line segment connecting the positioning portion and the center of the rotor may be orthogonal to the line segment connecting the through hole and the center of the rotor. Further, the through hole may be formed in a circular shape. Further, the through hole may be formed in a polygonal shape.

Further, according to the present invention, there is provided an electronic timepiece in which any one of the stepping motors is used as the stepping motor in an electronic timepiece in which a time hand is rotationally driven by a driving force of a stepping motor. To be done. The time hand is held by a large cogging torque in a stopped state, and is rotationally driven with low power consumption during rotational driving.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a stepping motor according to an embodiment of the present invention.
In particular, an example of a stepping motor having a configuration suitable for an electronic timepiece is shown. In FIG. 1, the stepping motor includes a stator 101 having a rotor housing hole 103, a rotor 102 rotatably arranged in the rotor housing hole 103, and a screw 1.
The magnetic core 108 is integrated with the stator 101 by the coils 12, 113, and the coil 109 wound around the magnetic core 108. When the stepping motor is used in an electronic timepiece, the stator 101 and the magnetic core 108 are screws 112, 1
It is fixed to the main plate (not shown) by 13.

The rotor 102 is magnetized to have two poles (S pole and N pole). Both outer ends 122, 1 of the stator 101
A plurality of (two in the present embodiment) recesses (outer notches) 10 are provided at positions facing each other with the rotor housing hole 103 interposed therebetween.
6, 107 are provided. Outer notches 106, 107
A plurality of saturable portions 110 and 111 forming a second saturable portion are formed between the rotor housing hole 103 and the rotor housing hole 103.
The saturable portions 110 and 111 are formed to have a second predetermined length Y.

The stator 101 has a rotor housing hole 103.
A plurality of (two in the present embodiment) positioning recesses (inner notches) 104 and 105 are provided at positions that are continuous with each other and face each other with the rotor housing hole 103 interposed therebetween. Further, the stator 101 is provided with a plurality of (two in the present embodiment) through holes 114 and 115 at positions facing each other with the rotor housing hole 103 interposed therebetween.

The line segment connecting the plurality of outer notches 106 and 107 and the line segment connecting the inner notches 104 and 105 are arranged so as to intersect with each other. The line segment connecting the inner notches 104 and 105 and the line segment connecting the through holes 114 and 115 are arranged so as to be orthogonal to each other. Between each of the through holes 114, 115 and the rotor housing hole 103, a plurality of first predetermined lengths X (two in this embodiment) from the end of each of the through holes 114, 115 to the rotor housing hole 103 are provided. ) Saturable units 116 and 117 are provided. Each saturable section 116, 117 constitutes a first saturable section. Through hole 114 and saturable portion 116
The area of the combined region 120 and the area of the combined region 121 of the through hole 115 and the saturable portion 117 are larger than the areas of the inner notches 104 and 105, respectively.

The second predetermined length Y is formed longer than the first predetermined length X, and the first saturable magnetic flux is generated in the stator 101 by the alternating signal supplied to the coil 109. After the portions 116 and 117 are magnetically saturated, the second saturable portions 110 and 111 are magnetically saturated. In addition, the saturable units 110 and 11
1, 116 and 117 are configured so as not to be magnetically saturated by the magnetic flux of the rotor 102.

The through holes 114 and 115 and the stator 101
Regions 118 and 119 having a third predetermined length Z are formed in the portion of the stator 101 between the outer ends of the. The third predetermined length Z is formed longer than the first predetermined length X and the second predetermined length Y, and the regions 118 and 119 are formed.
Is configured so as not to be saturated with the magnetic flux of the rotor 102. When the coil 109 is not excited, the two inner notches 104 and 105 work to cause the rotor 102 to move.
Cogging torque is generated due to a difference in magnetic energy depending on the rotation angle. The magnetic energy is lowest when the magnetic pole axis A of the rotor 102 is oriented in a direction orthogonal to the line segment connecting the inner notches 104 and 105.
The maximum is when the magnetic pole axis A of 02 is parallel to the line segment connecting the inner notches 104 and 105. Therefore, the rotor 102 is stably stopped at the position where the magnetic energy is the minimum, that is, the magnetic pole axis A is orthogonal to the line segment connecting the inner notches 104 and 105.

FIG. 2 is a characteristic diagram of the stepping motor according to the present embodiment. FIG. 2 (a) is a characteristic diagram in which the coil 109 is not excited, and FIG. 2 (b) is a state in which the coil 109 is excited. FIG. In addition, in FIG. 2, a position where a line segment connecting the inner notches 104 and 105 is orthogonal to the magnetic pole axis A of the rotor 102 as shown in FIG.

The operation of the stepping motor according to this embodiment will be described below with reference to FIGS. 1 and 2. When a rectangular wave pulse signal is supplied to the coil 109 and a current i is passed in the direction of the arrow in FIG. 1 to excite the coil 109, magnetic flux is generated in the stator 101 in the direction of the arrow C. Saturable part 1
Since the lengths of 16 and 117 are short, first, the saturable portion 11
6, 117 is magnetically saturated to increase the magnetic resistance, and the region 120 including the through hole 114 and the saturable part 116 and the region 1 including the through hole 115 and the saturable part 117 are combined.
21 is substantially equivalent to an inner notch having a larger area than the inner notches 104 and 105. That is, by exciting the coil 109, it is apparent that the rotor housing hole 103
The four inner notches are arranged at equal intervals along the circumference of. In the configuration where four inner notches are arranged at equal intervals,
As shown in FIG. 2 (b), the difference in magnetic energy becomes small, so the cogging torque also becomes small.

From this state, the saturable portions 110 and 111, which are longer than the saturable portions 116 and 117, are magnetically saturated. After that, the magnetic poles generated in the stator 101 and the rotor 10
The interaction with the two magnetic poles causes the rotor 102 to rotate 180 degrees in the direction of arrow B in FIG. At this time, the rotor 10
2 tries to stabilize by moving so that its magnetic pole axis A is orthogonal to the line segment connecting the region 120 and the region 121. That is,
By exciting the coil 109, the characteristic of the stepping motor changes from FIG. 2A to FIG. 2B, and even if the rotor 102 is rotationally driven by the magnetic energy that does not reach the maximum point D, the rotor 102 is driven. It becomes possible to rotate in the direction of arrow B by 180 degrees. After that, when the current supply to the coil 109 is stopped, the saturable portions 116 and 117 are not magnetically saturated and the apparent inner notches disappear, so that the rotor 102 is similar to the stepping motor shown in FIG.
Is stably stopped at a position where the magnetic pole axis A is orthogonal to the line segment connecting the inner notches 104 and 105, that is, a position corresponding to the positioning portion.

Next, when a pulse signal of a rectangular wave of opposite polarity is supplied to the coil 109 and a current is passed in the direction opposite to the arrow of FIG. 1, first, in the same manner as described above, the saturable portions 116 and 117 are magnetically saturated. The magnetic resistance increases, and the region 120 where the through hole 114 and the saturable portion 116 are combined, and the through hole 11
The region 121 including 5 and the saturable portion 117 is substantially equivalent to an inner notch having a larger area than the inner notches 104 and 105. Next, the saturable portions 110 and 111, which are longer than the saturable portions 116 and 117, are magnetically saturated.

Thereafter, the interaction between the magnetic poles of the stator 101 and the magnetic poles of the rotor 102 causes the rotor 102
Rotates 180 degrees in the direction of arrow B in FIG. At this time, the magnetic pole axis A of the rotor 102 is
It tries to stabilize by moving so as to be orthogonal to the line segment connecting. That is, by exciting the coil 109, the characteristic of the stepping motor changes from FIG. 2A to FIG. 2B, and even if the rotor 102 is rotationally driven by the magnetic energy that does not reach the maximum point D, the rotor is rotated. It becomes possible to rotate 102 in the direction of arrow B by 180 degrees.

After that, when the current supply to the coil 109 is stopped, the saturable portions 116 and 117 are no longer magnetically saturated, so that the apparent inner notches disappear, and the rotor 102 becomes the same as the stepping motor shown in FIG. , Its magnetic pole axis A
Is stably stopped at a position orthogonal to the line segment connecting the inner notches 104 and 105, that is, at a position corresponding to the positioning portion.

After that, by supplying signals having different polarities (alternating signals) to the coil 109 in this way, the above operation is repeated, and the rotor 102 is rotated 18 times.
The rotor 102 can be continuously rotated in the direction of the arrow B by 0 degrees, and the rotor 102 can be stably stopped at a position corresponding to the positioning portion. At this time, a low power consumption drive can be achieved by increasing the cogging torque in the state where the rotation is not performed and decreasing the cogging torque when the rotation is performed. The regions 118 and 119 in the present embodiment may be configured so as not to be magnetically saturated by the magnetic flux of the current of the coil 109, or may be configured to be magnetically saturated after the saturable portions 110 and 111 are magnetically saturated. Good. Further, although the line segment connecting the through holes 114 and 115 and the line segment connecting the inner notches 104 and 105 are orthogonal to each other, they may not necessarily be orthogonal to each other and may intersect at a predetermined angle.

In the embodiment shown in FIG. 1, the stator 1
Although the example in which the plurality of inner notches 104 and 105 and the plurality of through holes 114 and 115 are provided in 01 has been described, at least one of the inner notches and the through holes is one as shown in FIG. May be. That is, the inner notches are plural (for example, two) and the through hole is one, the inner notch is one, and the through holes are plural (for example, two), and the inner notch and the through hole are both one. Good. Also, one inner notch or one
When using two through holes, either the inner notch (inner notches 104 and 105 in FIG. 1) or the through hole (through holes 114 and 115 in FIG. 1) may be omitted when two holes are used. . When at least one of the inner notch and the through hole is one, it is preferable that the line segment connecting the inner notch and the center of the rotor be orthogonal to the line segment connecting the through hole and the center of the rotor.

FIG. 3 is a partial structural view showing a stator and a rotor of a stepping motor according to another embodiment of the present invention. The same parts as in FIG. 1 are allotted with the same reference numerals. FIGS. 3A and 3B are examples in which a plurality of (two in the present embodiment) inner notches are provided in the stator 101 and one through hole is provided, and the example in FIG. 10
1 has a plurality of inner notches 104 and 105 formed therein and one through hole 115. In the example shown in FIG. 1B, the stator 101 has a plurality of inner notches 104 and 105 formed therein. A through hole 114 is formed. The positions in which the through holes are provided are different between the examples of FIGS.

FIGS. 3C and 3D show a stator 101 with one
A plurality of inner notches are provided and a plurality of inner notches (two in this embodiment) are provided.
In this example, one inner notch 105 is formed in the stator 101 and a plurality of through holes 114 and 115 are formed in the example shown in FIG. In this example, one inner notch 104 is formed in the stator 101 and a plurality of through holes 114, 115 are formed. The example of FIGS. 3C and 3D is different in the position where the inner notch is provided.

FIGS. 3 (e) to 3 (h) show one stator 101.
This is an example in which one inner notch and one through hole are provided. In the example of FIG. 7E, one inner notch 105 is formed in the stator 101 and one through hole 115 is formed. In the example of FIG. (F), one inner notch 105 is formed in the stator 101 and one through hole 114 is formed, and in the example of the same figure (g), one inner notch 104 is formed in the stator 101. In addition, one through hole 115 is formed, and in the example of FIG. 6H, one inner notch 104 is formed in the stator 101 and one through hole 114 is formed. In the examples of (e) to (h) of the same drawing, the positions at which the inner notches or the through holes are provided are different. 3 (a)-(h)
1 operates in the same manner as the embodiment of FIG. 1, the cogging torque is increased when the rotor 102 is not rotationally driven, and the cogging torque is reduced when the rotor 102 is rotationally driven. This enables low power consumption driving.

As described above, in the stepping motor according to the embodiment of the present invention, the positioning portions 104 and 10 that determine the stop positions of the rotor housing hole 103 and the rotor 102.
5 has a stator 101, a rotor 102 arranged in a rotor housing hole 103, and a coil 109. The rotor 102 is rotated by supplying an alternating signal to the coil 109 to generate a magnetic flux in the stator 101. In the stepping motor configured to stop the rotor 102 at the position corresponding to the positioning portions 104 and 105, the first predetermined length X from the end portion of the rotor housing hole 103.
Of the first saturable portion 116, 117 having through holes 114, 115 formed therein.
6, 117 are magnetically saturated by the magnetic flux generated in the stator 101 by the alternating signal supplied to the coil 109, and the through holes 114, 115 and the first saturable portions 116, 117 corresponding to the through holes 114, 115 are combined. The areas are characterized by being larger than the areas of the positioning portions 104 and 105, respectively.

Here, a plurality of positioning portions 104 and 105 are provided at positions facing each other with the rotor housing hole 103 interposed therebetween, and the through holes 114 and 115 are provided in the rotor housing hole 1.
The line segment connecting the centers of the plurality of positioning portions 104 and 105 and the line segment connecting the centers of the plurality of through holes 114 and 115 are orthogonal to each other. There is. In addition, the positioning units 104 and 105
When at least one of the through holes 114 and 115 is formed, the center of the positioning portion and the rotor 1
The line segment connecting the center of 01 and the line segment connecting the centers of the through holes 114 and 115 and the rotor 102 are orthogonal to each other.

Therefore, since the cogging torque becomes large when the coil 109 is not excited, the stepping motor is driven in the electronic timepiece in which the time hands such as the second hand and the minute hand are rotationally driven by the driving force of the stepping motor. If it is used as a stepping motor for a vehicle, it is possible to prevent the pointer from being displaced due to a disturbance or a drop impact. Further, in the state where the coil 109 is excited, the cogging torque becomes small and the power consumption can be reduced.

In the above embodiment, the circular through holes 114 and 115 are used as the through holes, but various modifications such as a polygonal shape such as a square or a triangle are possible. Further, although the line segment connecting the inner notch and the center of the rotor and the line segment connecting the through hole and the center of the rotor are arranged to be orthogonal to each other, they are not necessarily arranged to be orthogonal to each other.

[0035]

According to the stepping motor of the present invention, it is possible to reduce the power consumption by increasing the cogging torque when the coil is not excited and decreasing the cogging torque when the coil is excited. Become. Further, according to the electronic timepiece of the invention, it is possible to reduce the current consumption by increasing the cogging torque when the coil is not excited and decreasing the cogging torque when the coil is excited. It is possible to drive with low power consumption and to stably rotate and rotate the time hand.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a stepping motor according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of the stepping motor shown in FIG.

FIG. 3 is a configuration diagram showing a partial configuration of a stepping motor according to another embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional stepping motor.

[Explanation of symbols]

101 ... Stator 102 ... Rotor 103 ... Rotor housing holes 104, 105 ... Recesses (inner notches) 106, 107 ... Recesses (outer notches) 108 ... Magnetic core 109 ... coils 110, 111 ... second saturable portions 114,115 ... through holes 116,117 ... first saturable portions 118-121 ... regions

Claims (8)

[Claims] 1. A stator having a rotor accommodating hole and a positioning portion for determining a stop position of the rotor, a rotor arranged in the rotor accommodating hole, and a coil, and an alternating signal is supplied to the coil. A stepping motor configured to rotate the rotor by generating magnetic flux in the stator and to stop the rotor at a position corresponding to the positioning portion, the stepping motor having a first predetermined length from an end of the rotor housing hole. A through hole formed with a first saturable portion of, wherein the first saturable portion is magnetically saturated by the magnetic flux generated in the stator by the alternating signal supplied to the coil,
The stepping motor is characterized in that an area including the through hole and the first saturable portion corresponding to the through hole is larger than an area of the positioning portion. 2. The stepping motor according to claim 1, wherein a plurality of the through holes are provided at positions facing each other with the rotor accommodating hole interposed therebetween. 3. The stepping motor according to claim 1, wherein a plurality of the positioning portions are provided at positions facing each other with the rotor housing hole interposed therebetween. 4. A plurality of the positioning portions are provided at positions facing each other across the rotor housing hole, and a plurality of the through holes are provided at positions facing each other across the rotor housing hole. 2. The stepping motor according to claim 1, wherein a line segment connecting the positioning portions of and the line segment connecting the plurality of through holes are orthogonal to each other. 5. The stepping motor according to claim 1, wherein a line segment that connects the positioning portion and the center of the rotor is orthogonal to a line segment that connects the through hole and the center of the rotor. 6. The stepping motor according to claim 1, wherein the through hole is formed in a circular shape. 7. The stepping motor according to claim 1, wherein the through hole is formed in a polygonal shape. 8. An electronic timepiece in which a time hand is rotationally driven by a driving force of a stepping motor, wherein the stepping motor according to any one of claims 1 to 7 is used as the stepping motor. .