JPH10174412A - Stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the torque of a stepping motor and improve high-speed response. SOLUTION: By increasing magnetic resistance between a stator 103a facing a first rotor yoke 102a of a stator 103 in a hybrid-type stepping motor and a stator 103b facing the second rotor yoke 102b, ineffective magnetic flux is prevented, which is caused by magnetic flux falling out directly into the second rotor yoke 102b via the stator from the first rotor yoke 102a. By increasing the magnetic resistance of the stator in a coil, it is possible to reduce the inductance and improve the high-speed response of the stepping motor.

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 more particularly to a stator structure of a so-called hybrid type motor.

[0002]

2. Description of the Related Art As shown in FIG. 4 which is a perspective view of a step motor, FIG. 5 which is a sectional view of the step motor, and FIG. The rotor yokes 2a and 2b with teeth are arranged at the same angle, and the phase of the teeth is set to 18 electrical degrees.
The stator 3 is shifted by 0 degrees, and the stator 3 having the teeth 3a provided at the tips of the plurality of arms 3b is disposed so as to face this. A coil 4 is wound around the stator 3, and a motor torque is generated by energizing the coil 4.

More specifically, the magnetic flux generated from the magnet 1 enters the arm 3b from the teeth 3a of the stator 3 facing the rotor yoke 2a, passes through the coil via the arm 3b, and passes through the coil. A magnetic circuit which enters another arm 3b1 of the stator 3 via the outer periphery 3c of the stator 3 and returns to the magnet 1 via the rotor yoke 2b which passes through the coil 4 and faces the teeth 3a1 of the stator 3 doing. At this time, the magnetic flux passing through the coil 4 is an effective magnetic flux for generating the torque of the motor.

Since the phases of the rotor core 2a and the rotor core 2b are shifted by 180 degrees, the rotor core 2a and the stator 3
The space between the teeth 3b is small and the magnetic resistance is small. However, since the teeth do not match between the rotor core 2b and the stator three teeth 3a, the space is large and the magnetic resistance is increased.

[0005]

However, in this conventional structure, the rotor core 2a and the rotor core 2b have a phase of 1 unit.
When the rotor core 2a and the teeth 3a of the stator 3 are opposed to each other and are aligned with each other, the gap between the spaces is small and the magnetic resistance is small. However, since the phase is shifted between the teeth 3a of the rotor core 2b and the teeth 3a of the stator 3, the teeth do not match. For this reason, the space between the rotor core 2b and the teeth 3a of the stator 3 has been designed to have a large space gap and a large magnetic resistance. Even if the rotor core 2b does not match the teeth 3a, the magnetic resistance decreases as the shape of the teeth 3a decreases, and the magnetic flux originally generated from the magnet 1 faces the rotor yoke 2a. It flows from the teeth 3a provided on the arm 3b of the stator 3 to the stator 3, and the stator 3
Of the stator 3 through the coil 4 through the arm 3b
Into the arm 3b1 of another stator 3 via the outer periphery 3c of the stator 3, enter the arm 3b1 of the stator 3, and pass through the coil 4 via the rotor yoke 2b facing the teeth 3a1 of the stator 3. The magnetic circuit returning to the magnet 1 should have constituted the magnetic flux generated by the magnet 1 from the rotor yoke 2a to the teeth 3a provided on the arm 3b of the stator 3 facing the rotor yoke 2a. Arm 3
b, the flow of the magnetic flux which does not pass through the coil and returns from the arm 3b to the rotor yoke 2b through the teeth 3a (arrow 5 in the figure) becomes large, and does not contribute to the generation of torque. Large magnetic flux was generated. Further, since the coil 4 is wound around the arm 3b of the stator 3, the magnetic circuit is clogged in the coil 4, so that the inductance becomes large. The inductance slows the rise of the current flowing into the coil 4 and reduces the high-speed response of the step motor.

[0006]

According to the present invention, there are provided first and second disk-shaped rotor yokes, each of which is made of a magnetic material disposed with a magnet interposed therebetween and has teeth formed on an outer peripheral portion thereof, and a rotating member which rotates together with the magnet and the rotor yoke. A rotor consisting of a shaft and
A stator having teeth formed at the tips of a plurality of arms opposed to the teeth of the rotor yoke, a coil wound around the arms of the stator, and a bearing member engaged with the stator to support the rotating shaft; Wherein the magnetic resistance of the magnetic circuit between the portion of the arm provided on the stator facing the first rotor yoke and the portion facing the second rotor yoke is increased. It is characterized by things.

Further, the stator has a cross section in the radial direction of the rotating shaft having a small cross-sectional area at a portion facing the first rotor yoke and the second rotor yoke, and at a portion therebetween. It is characterized by things.

Further, the portion of the arm portion provided on the stator, from a portion facing the first rotor yoke to a portion facing the second rotor yoke, substantially has a portion facing the magnet holding the coil. It is characterized by being cut out to the wound inside.

(Operation) In the step motor constructed as described above, the magnetic resistance between the stator portion facing the first rotor yoke of the stator and the stator portion facing the second rotor yoke is increased, so that the step motor is generated from the gnet. The magnetic flux flows from the first rotor yoke to the stator from the teeth provided on the arm of the stator opposed thereto, and the flow of the magnetic flux that does not pass through the coil and returns from the stator to the second rotor yoke is large. That is, the effective magnetic flux passing through the coil can be significantly increased, and the torque of the motor can be increased.

Further, by shaving the portion of the arm of the stator facing the magnet to the inside of the coil winding portion,
The inductance of the coil can be reduced, and the high-speed response of the motor can be improved.

[0011]

FIG. 1 is a perspective view of a stator and a rotor of a hybrid type stepping motor according to the present invention. FIG. 2 is a sectional view of the step motor of the present invention.

The first rotor yoke 102a and the second rotor yoke 1 are provided with teeth on the outer periphery on both sides of the magnet 101.
Nos. 02b are attached, and the rotation shaft 100 passes through these centers. On the outer periphery of the rotor, teeth 103a facing the rotor yoke 102a and teeth 103b facing the rotor yoke 102b are arranged on the stator 103. The stator 103 has eight arm portions 103c. Each of the arms 103c is covered with an insulator 104 (a plastic molded product for insulation), and a coil 105 is wound around the insulator 104. These coils 105 are connected in series with every other arm 103c, but the winding direction is reversed every other arm 103c. This is because the magnetic flux from the magnet 101, through the first rotor yoke 102a, and from the arm 103c of the stator 103 through the coil 105 flows to the arm 103c of the stator 103 through the outer periphery 103d of the stator 103, and is wound around the outer periphery of the arm 103c. This is because the direction of the magnetic flux is reversed in the coil 105 which is one distance away from the coil 105 in order to penetrate the turned coil 105, so that the magnetic flux is effectively picked up by the coil 105.

On both sides of the stator 103, end caps 107a and 107b for mounting bearings 106a and 106b for supporting the rotating shaft 100 are attached.
It is fastened to the stator 103 by the screws 108. The arm portion 103c of the stator 103 has a portion facing the first rotor yoke 103a and the second rotor yoke 103
b has teeth, but a portion facing the magnet 101 in the middle is cut off by the arm 103c of the stator 103.

With such a configuration, the coil 10
Since there is no central portion of the arm portion 103c of the stator 103 inside 5, the inductance of the coil 105 is extremely reduced. Since the strength of the stator is reduced in the cut portion of the stator 103, in order to prevent the strength from decreasing, the strength can be prevented by filling a non-magnetic material such as an adhesive.

FIG. 3 shows the arm 103 of the stator 103 shown in FIG.
It is an exploded perspective view of c. In this embodiment, the stator 103 is configured by a thin laminated plate, and a silicon steel plate is generally used as the laminated plate. The cross-sectional shape of the stator 3 is different between a portion facing the first and second rotor yokes 102a and 102b and an intermediate portion therebetween. In this example, a large hole 103e is formed in the arm 103c of the stator 3.
Has been opened. This configuration also allows the stator 103 to face the first rotor yoke 102a.
Of the stator 103 between the arm 103c of the stator 103 and the arm 103c of the stator 103 facing the second rotor yoke 102b.
3 can be increased and the flow of magnetic flux can be controlled. In this example, since the stator 3 is not cut off, a decrease in the strength of the arm 103c of the stator 3 can be prevented.

In this embodiment, an example of the inner rotor type step motor in which the rotor is inside the stator is shown. However, it is obvious that the same applies to an outer rotor type step motor in which the rotor is outside the stator. It is.

[0017]

As described above, the first and second disk-shaped rotor yokes, which are made of a magnetic material and sandwiched between magnets and have teeth formed on the outer periphery thereof, and the rotating shaft that rotates together with the magnet and the rotor yoke. A rotor having teeth formed at the tips of a plurality of arms, facing the teeth of the rotor yoke, a coil wound around the arms of the stator, and engaging the stator to form the rotating shaft. In a stepping motor including a bearing member that supports the shaft, the magnetic resistance of the magnetic circuit between the portion of the arm portion provided on the stator facing the first rotor yoke and the portion facing the second rotor yoke is large. With this configuration, the magnetic flux flowing from the rotor to the stator can escape from the stator to the rotor again without passing through the coil, and can be prevented from becoming an ineffective magnetic flux. Tatoruku could dramatically be increased.

[0018] Further, the stator is configured such that the cross-sectional shape of the rotating shaft in the radial direction is different between a portion facing the first rotor yoke and the second rotor yoke and a portion therebetween. Increase the magnetic resistance of the arm portion, the magnetic flux flowing from the first rotor yoke to the stator,
As a result, the magnetic flux escaped from the stator to the second rotor, did not pass through the coil, and was prevented from becoming an ineffective magnetic flux. As a result, the motor torque could be dramatically increased.

Further, in the stator, a portion of the arm portion provided on the stator from a portion facing the first rotor yoke to a portion facing the second rotor yoke, a portion substantially facing the magnet holds the coil. By cutting out the inside of the winding, the inductance of the coil wound around the arm of the stator is reduced, the rise of the current flowing into the step motor can be accelerated, and the responsiveness of the step motor is greatly improved. Was completed. This effect can be obtained, for example, by making a hole in the surface shape of the intermediate portion of the arm portion of the stator facing the magnet, thereby increasing the magnetic resistance and obtaining the same effect. As described above, the effect of the present invention is very large, and greatly contributes to the improvement of the torque and the response of the step motor.

[Brief description of the drawings]

FIG. 1 is a perspective view of a stator and a rotor of a hybrid type stepping motor according to the present invention.

FIG. 2 is a sectional view of a step motor of the present invention.

FIG. 3 is an exploded perspective view of a stator of the step motor of the present invention.

FIG. 4 is an exploded perspective view of a conventional step motor.

FIG. 5 is a perspective view of a stator of a conventional step motor.

FIG. 6 is a sectional view of a conventional step motor.

[Explanation of symbols]

 101 Magnet 102a First rotor yoke 102b Second rotor yoke 103 Stator 103a, 103b Teeth 103c Arm 103d Outer periphery 105 Coil

Claims (3)

[Claims] 1. A rotor comprising a disk-shaped first rotor yoke and a second rotor yoke, which are made of a magnetic material and have teeth formed on the outer periphery thereof, with a magnet interposed therebetween, and a rotor comprising the magnet and a rotating shaft which rotates together with the rotor yoke. A stator having teeth formed at the tips of a plurality of arms opposed to the teeth of the rotor yoke, a coil wound around the arms of the stator, and a bearing engaged with the stator and axially supporting the rotating shaft; A step motor comprising a member, wherein a magnetic resistance of a magnetic circuit between a portion of the arm provided on the stator facing the first rotor yoke and a portion facing the second rotor yoke is increased. A step motor. 2. The stator has a cross-sectional shape in a radial direction with respect to the rotating shaft, a portion facing the first rotor yoke and the second rotor yoke, and a small cross-sectional area between the portions. The step motor according to claim 1, wherein 3. A portion of the arm provided on the stator, from a portion facing the first rotor yoke to a portion facing the second rotor yoke, a portion substantially facing the magnet winds the coil. 2. The step motor according to claim 1, wherein the inside of the step motor is cut out.