JPH10290559A - Stepping motor, time measuring apparatus and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepping motor in which the flux of a rotor can be utilized effectively without causing deformation due to welding heat of a stator or fluctuation in the performance of product due to degradation in the characteristics of material while sustaining mass productivity by employing a stator electrode of integral structure. SOLUTION: A stepping motor comprising a permanent magnet rotor for field, and a stator 2 made of a soft magnetic material and surrounding the stator is provided with a slit 31 for dividing the boundary of a pole part 26 having narrow magnetic path width so that the stator 2 constitutes two or more facing pole parts 26 and a reinforcing member 33 made of a nonmagnetic material is bonded to a part of the stator 2 so that the pole part of the stator is integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step motor suitable as a power source for a small electronic device such as a wristwatch device,
The present invention relates to a timing device and an electronic device.

[0002]

2. Description of the Related Art FIG. 1 shows a schematic configuration of a step motor used as a power source of a small electronic device such as a wristwatch device, and FIG. 2 shows a schematic configuration of a timing device 10 equipped with a step motor. It comprises a rotor 1 magnetized in two directions, a stator (stator 2) having a hollow portion for accommodating the rotor, and a magnetic core 3 on which a coil 4 is wound. The magnetic core 3 is overlaid on the stator 2, and these are collectively fixed to the main plate with screws. In a state where the coil 4 is not excited, the rotor 1 is regulated by the inner notch 23 provided in the hollow portion of the stator, and the inner notch 2
The rotor 1 is stationary at a position where the magnetic pole of the rotor 1 faces in a direction perpendicular to the position 3.

In the excited state, the rotor 1 can be driven to rotate by 180 degrees at a specific timing by supplying a drive pulse to the coil 4 from the control device 12, and the driving force of the rotor is transmitted by the wheel train 11. You can move the needle.

When the supply of the driving pulse is stopped, the rotor 1 is again rotated in a direction perpendicular to the position of the inner notch 23.
Stand still with its magnetic pole facing.

Next, as a conventional example, FIG. 3 is an enlarged view of a portion around a hollow portion for accommodating a rotor of the stator 2. A hollow portion 22 for accommodating the rotor is provided at the center of the stator 2, and a bridge 25 having a narrow magnetic path is provided with a notch from the outer periphery by an outer notch 24 to form two opposing magnetic poles 26. Further, by providing an inner notch 23 on the inner periphery of the hollow portion 22, the stationary position of the rotor is regulated. In the case of this conventional example, two opposed magnetic poles 26 of the stator 2 are integrated by a bridge 25 having a narrow magnetic path width. Therefore, the magnetic flux from the rotor forms a long magnetic path passing through the magnetic core 3 and a short magnetic path passing through the bridge 25. Of these, the short magnetic path passing through the bridge 25 is the exciting coil 4
And does not work effectively at the time of driving.

In other words, the magnetic flux forming the short magnetic path passing through the bridge 25 becomes a leakage magnetic flux, and therefore, the amount of effective magnetic flux interlinking the coil which is originally required for driving is greatly reduced.

Next, as a second conventional example, FIG. 4 is an enlarged view of the periphery of a hollow portion for accommodating the rotor of the stator 2. In the configuration of the prior art, two magnetic poles 26 are formed by welding a member 27 made of a non-magnetic material to the center of the bridge 25.

In the case of this conventional example, it is necessary to weld a portion where the magnetic path width becomes the narrowest, so that the welding accuracy, deformation of the welding peripheral portion due to welding heat, and deterioration of the material properties of the welding peripheral portion due to local heating. And other problems. Therefore, when such a stator is used for a step motor, the product performance greatly varies.

As described above, it is necessary to form the stator into an integral structure because of its superiority in mass production assembling. However, any conventional example still has a problem.

[0010]

SUMMARY OF THE INVENTION Accordingly, the inventions of claims 1 to 3 are based on the fact that the stator poles are formed in an integral structure to maintain mass productivity while reducing the deformation of the stator due to welding heat and deterioration of material properties. An object of the present invention is to provide a step motor capable of effectively utilizing the magnetic flux of a rotor without causing variations in product performance.

A fourth object of the present invention is to provide a small and low power consumption time-measuring device by using a stepping motor having the object of the first to third aspects as a power source. .

A fifth object of the present invention is to provide a small-sized and low-power-consumption electronic device by using a stepping motor having the objects of the first to third aspects as a power source. .

[0013]

In order to achieve the above object, an invention according to claim 1 is a fixing device comprising a permanent magnet rotor for a field and a soft magnetic material disposed so as to surround the rotor. In the step motor constituted by the stator, the stator constitutes two or more opposed magnetic pole portions,
A slit is provided to divide a portion where the magnetic path width becomes narrower as a boundary of the magnetic pole portion, and further, a reinforcing member made of a non-magnetic material is provided on a part of the stator so as to integrate the magnetic pole portion of the stator. It is characterized by being fixed.

Here, there is a method in which the stator and the reinforcing member made of a non-magnetic material are fixed by welding so that the magnetic pole portions are integrated as in the second aspect of the present invention.

Further, a third aspect of the present invention is a method of fixing a portion to be fixed at a location other than a portion having a minimum magnetic path width.

[0016] Further, the invention according to claim 4 is the invention according to claim 1.
According to a third aspect of the present invention, there is provided a timing device using a stepping motor as a power source.

According to a fifth aspect of the present invention, there is provided an electronic apparatus using a step motor as a power source having the features of the first to third aspects of the present invention.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 5 is a configuration diagram of a step motor according to the embodiment. However, the embodiment shown here shows the case of a step motor for a timepiece.

The stepping motor of the present invention comprises a disk-shaped rotor 1 magnetized to two poles, a stator 2 having a hollow portion for accommodating the rotor, and a magnetic core 3 wound with a coil 4. ing. The magnetic core 3 is overlaid on the stator 2, and these are collectively fixed to the main plate with screws.

FIG. 6 is an enlarged view of the stator magnetic pole portion of the step motor according to the first and second aspects of the present invention.

A hollow portion 22 for accommodating the rotor is provided at the center of the stator 2, a bridge 32 having a narrow magnetic path width is provided with a notch from the outer circumference by an outer notch 25, and a slit 31 is provided from the inner circumference of the hollow portion 22. Thus, two opposed magnetic poles 26 are formed.

The notch formed by the outer notch 25 is reinforced from the outer periphery with a reinforcing member 33 made of a non-magnetic material, and is welded by a magnetic pole portion 26 of the stator and a welded portion 34 at the end of the reinforcing member 33 so as to face the left and right facing magnetic poles. 26 has an integral structure.

When the step motor is driven, the stator 2
The rotor 1 made of a permanent magnet enters the hollow portion 22 of the first embodiment. Magnetic flux from the permanent magnet rotor rarely flows through the reinforcing material 33 which is a non-magnetic material.
6 will be magnetically separated.

FIG. 8 shows that a Sm2Co17-based rare earth sintered magnet is used for the rotor and a saturated magnetic flux density of 7500 is used for the stator.
The change of the effective magnetic flux of the magnetic core with respect to the rotation angle of the rotor when the permalloy material of [G] is used is shown. FIG. 8 shows a conventional example in which the left and right magnetic poles are connected at a narrow portion of the magnetic path width as shown in FIG.

As described above, when the conventional example and the embodiment of the present invention are compared, the embodiment of the present invention causes a significant increase in effective magnetic flux of up to 30%.

When such a stator is used as a step motor, the motor efficiency is greatly improved.

In this embodiment, the reinforcing member 33 and the left and right facing magnetic poles 26 are welded at the welding portion 34 at the end of the reinforcing member. Since the welded portion 34 is a portion having a wider magnetic path width than the bridge 32, thermal deformation of the stator member due to welding and deterioration of the magnetic characteristics of the stator due to local heating can be significantly suppressed.

Therefore, when the present embodiment is compared with a conventional example in which a non-magnetic material is welded to a bridge having a narrow magnetic path width as shown in FIG. 4, the present embodiment has less variation in product performance and mass production. It will improve the yield at the time.

As another embodiment, as shown in FIG. 7, a reinforcing member 33 made of a non-magnetic material is reinforced in the hollow portion 22 of the stator 2 from the inner periphery, and the magnetic pole portion 26 of the stator and the end of the reinforcing member 33 are provided. The left and right opposed magnetic poles 26 are welded at the welding portions 34 of the portions, and may be formed as an integrated structure.

In this embodiment, the reinforcing member 33 having a semicircular arc shape is welded so as to be in contact with the outer notch 24 of the stator 2. However, the reinforcing member may have any shape. It is sufficient if the magnetic pole 26 can be connected as an integral structure.

Such a highly efficient step motor with little variation in product performance can be reliably driven with a constant power consumption, and is therefore suitable as a power source for a relatively small timepiece such as a wristwatch.

The stepping motor of the present invention can be applied to electronic instruments such as barometers, altimeters, and printers, in addition to timepieces such as clocks.

[0034]

According to the first to third aspects of the present invention, since the stator magnetic poles have an integral structure, the mass productivity is maintained, and the variation in product performance due to the deformation due to the welding heat of the stator and the deterioration of the material characteristics occur. It is possible to provide a stepping motor that can effectively use the magnetic flux of the rotor without causing the stepping motor.

According to a fourth aspect of the invention, a stepping motor having the effects of the first to third aspects of the invention is used as a power source, so that it is possible to provide a small time-measuring device with low power consumption.

According to a fifth aspect of the present invention, a small-sized and low-power-consuming electronic device can be provided by using a step motor having the effects of the first to third aspects as a power source.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a step motor.

FIG. 2 is a diagram showing a schematic configuration of a timing device equipped with a step motor.

FIG. 3 is an enlarged view of a magnetic pole portion of a conventional stator.

FIG. 4 is an enlarged view of a magnetic pole portion of a conventional stator.

FIG. 5 is a configuration diagram of a step motor according to the embodiment.

FIG. 6 is an enlarged view of a magnetic pole portion of the stator according to the embodiment.

FIG. 7 is an enlarged view of a magnetic pole portion of a stator showing another embodiment.

FIG. 8 is a diagram showing a change in an effective magnetic flux amount of a magnetic core.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Stator 3 ... Magnetic core 4 ... Coil 7 ... Screw hole 10 ... Timing device 11 ... Wheel train 12 ... Control device 22 ... Hollow part 23 ... Inner notch 24 ... Outer notch 25 ... Bridge 26 ... Magnetic pole 27 ... Member 31 ... Slit 32 ... Bridge 33 ... Reinforcement 34 ... Welded part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02K 37/24 H02K 37/24 U

Claims (5)

[Claims] 1. A stepping motor comprising a permanent magnet rotor for a field and a stator made of a soft magnetic material disposed so as to surround the rotor, wherein the stator has two or more opposed magnetic poles. In order to constitute the portion, a slit is provided to divide the narrowed portion of the magnetic path width that is the boundary of the magnetic pole portion, and further, a reinforcing member made of a non-magnetic material is provided so that the magnetic pole portion of the stator is integrated. A step motor fixed to the slit portion. 2. The step motor according to claim 1, wherein the method of fixing the reinforcing member is welding. 3. A step motor according to claim 1, wherein the fixing portion of the reinforcing member is other than a portion having a minimum magnetic path width. 4. A timing device using the step motor according to claim 1 as a power source. 5. An electronic apparatus using the step motor according to claim 1 as a power source.