JP2000184669A - Small motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small motor comprising an auxiliary member which raises or lowers a detent torque that occurs at non-electrification. SOLUTION: Related to stator members 1a and 1b wherein a plurality of strip-like main magnetic poles 2A and 2B are erected in cylinder inward from a bottom surface of a stator jacket formed into cup shape, the edges of cup-type are faced and hit each other so that each strip-like main magnetic pole is adjoined crosswise, and a rotator 6 born for free rotation through the gap and inner peripheral surface of a stator is provided wherein two stators with coils 4A and 4B allocated around the main magnetic pole are coaxially provided while connected together. Here, the rotator comprises, as a main body, a cylindrical permanent magnet where N and S magnetic poles are alternately magnetized on the outer peripheral surface while N and S magnetic poles are alternately magnetized on the inner peripheral surface with the same pitch as the outer peripheral surface, auxiliary magnetic poles 8A and 8B which face the inner peripheral surface with a gap in between are provided to a stator member while coupled at 1/2 pitch of the main magnetic pole allocation pitch while provided at a position across the main magnetic pole on the same side of two stators.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small electric motor, and more particularly to a stator having a plurality of magnetic poles and windings arranged in a bowl-shaped stator member, and rotating through the stator and a gap. The present invention relates to a structure of a small motor including a permanent magnet rotor freely supported by a shaft.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view of an example of a conventional small motor. In the figure, reference numerals 1A and 1B denote outer shells of a bowl-shaped stator, 2A and 2B denote a plurality of strip-shaped main magnetic poles standing in a cylindrical shape in the axial direction from an end face of the outer shell.
A and 3B are bobbins for winding windings, 4A and 4B are windings,
Reference numeral 5 denotes a bearing, 6 denotes a rotor mainly composed of a permanent magnet, and 7 denotes a rotor shaft. FIG. 7 is a perspective view of the rotor 6 of the motor shown in FIG. 1, in which N and S magnetic poles 6-1 are alternately magnetized on the outer peripheral surface of the rotor 6 at substantially equal intervals. The small motor shown in FIG.
For example, when alternating currents having the same frequency and different phases are applied to the two windings 4A and 4B, the rotor 6 is attracted and repelled by the magnetic poles of the stator and the permanent magnets of the rotor, so that the rotor 6 has a speed proportional to the frequency of the alternating current. It is known to rotate and operate as a synchronous motor.

[0003]

However, in the electric motor shown in FIG. 6, when the energization is stopped, after the rotor stops, an attractive force acts between the permanent magnet of the rotor and the main magnetic pole of the stator.
A detent torque acts to maintain the stopped position of the rotor. This day tent torque may be beneficial or inconvenient depending on the intended use of the motor. For example, in a device that winds up a load, in an application in which the energization is stopped at a certain position and stopped at that position, the stop position can be held by this detent torque.
On the other hand, in the case of coupling with the load via the speed reducer, the speed reducer acts to increase the detent torque even if the position is manually moved from the load side with the power supply stopped. Therefore, there is a problem that the operation cannot be easily performed manually. The present invention solves the above-described problems and reduces the detent torque.
Another problem is to obtain a small motor having a configuration that can be enlarged.

[0004]

According to the present invention, there are provided two stator members each having a plurality of strip-shaped main magnetic poles rising in a cylindrical shape inward from the bottom surface of a bowl-shaped stator jacket. Two bowl-shaped stators, in which the edges of the bowl shape are opposed to each other, are arranged so that the strip-shaped main magnetic poles cross each other, and windings are arranged around the outer circumference of the strip-shaped main magnetic pole arranged in a cylindrical shape, are coaxially arranged. A stator arranged and connected, facing the inner peripheral surface of the stator via a gap,
In a small motor in which a rotor mainly composed of a cylindrical permanent magnet in which N and S magnetic poles are alternately magnetized on its outer peripheral surface is rotatably supported, an inner peripheral surface of the permanent magnet has the same pitch as its outer peripheral surface. The N and S magnetic poles are alternately magnetized, and an auxiliary magnetic pole is provided on the stator member facing the inner peripheral surface of the permanent magnet via an air gap, and the auxiliary magnetic pole is one of the arrangement pitches of the main magnetic poles. The auxiliary magnetic poles are arranged in pairs at a pitch of / 2, and the auxiliary magnetic poles are arranged at positions crossing the main magnetic poles on the same side of each of the two stators. Alternatively, N and S magnetic poles are alternately arranged on the inner peripheral surface of the permanent magnet at the same pitch as the outer peripheral surface, and
The auxiliary magnetic poles are arranged so as to be shifted by / 4 pitch so that the auxiliary magnetic poles are located at the same position as one main magnetic pole of the two stators.

[0005]

FIG. 1 is a sectional view showing the structure of a small electric motor according to the present invention, and FIG. 2 is a perspective view of a rotor 6 of the small electric motor shown in FIG. In FIG. 1, reference numerals 1A and 1B denote outer shells of a bowl-shaped stator, and 2A and 2B denote a plurality of strip-shaped main magnetic poles standing in an axial direction from an end face of the outer shell.
A and 3B are bobbins for winding windings, 4A and 4B are windings,
5 is a bearing, 6 is a rotor mainly composed of a permanent magnet, and 7 is a rotor shaft. The parts so far are the same as those in FIG. 6 of the prior art, but as shown in FIG. N and S magnetic poles 9 are magnetized on the inner peripheral surface of the permanent magnet rotor 6 at the same pitch as the outer peripheral surface thereof, and the auxiliary magnetic poles 8A and 8B are fixed via the air gap with the magnetic pole 9 on the inner peripheral surface of the permanent magnet rotor 6. It is arranged on the child members 2A, 2B. Auxiliary magnetic poles 8A and 8B provided in the magnetic pole 9 on the inner peripheral surface of the rotor 6 with a gap therebetween constitute a plurality of strip-shaped main magnetic poles 2 facing the outer peripheral surface of the permanent magnet rotor 6.
A pair is provided at half the pitch of A and 2B. FIG. 3 is a perspective view showing an example of the structure of the bowl-shaped stator 1A shown in FIG. 1; FIG. 3A is a bowl-shaped jacket portion; 2A is a plurality of strip-shaped main magnetic poles;
Has an auxiliary pole. The strip-shaped main pole 1 shown in FIG.
A and the auxiliary magnetic pole 8A have a tapered shape instead of a constant width, but such a shape is appropriately selected as necessary.

Next, the operation of the small electric motor according to the present invention shown in FIG. 1 will be described with reference to the developed view of FIG. FIG. 4 shows the relationship between the main magnetic poles 2A and 2B of the stators 1A and 1B and the magnetic pole of the permanent magnet 6 of the rotor, the relationship between the auxiliary magnetic pole 8A and the magnetic pole 9 on the inner peripheral surface of the rotor, and the detent. FIG. 4 is an explanatory diagram for schematically explaining a relationship with a torque, in which only a part of a magnetic pole of a stator and a permanent magnet of a rotor are illustrated.
The upper half of FIG. 4 shows the relative positions of the main magnetic poles 2A and 2B of the stator, the magnetic poles of the permanent magnet 6 of the rotor, the auxiliary magnetic poles 8A, and the magnetic poles 9 on the inner peripheral surface. The main magnetic poles 2B of the 2A and B phases each have two bowl-shaped jackets, and the main magnetic poles are alternately arranged.
B, 2B 'and the main poles 2A, 2A', and 2
The pitch of B, 2B 'is arranged at a pitch 1.5 times the pitch of the magnetic poles of the permanent magnet 6 of the rotor, and the relationship between the main magnetic poles 2A and 2B is １ ／ of the arrangement pitch of the respective magnetic poles. It is arranged to be. Further, the auxiliary magnetic poles 8 are paired at half the pitch of the main magnetic pole 2A, and are provided at positions where 1/2 of the magnetic pole width overlaps both the main magnetic poles 2A and 2B. By arranging in this manner, the configuration is such that the detent torque can be minimized.

In the lower half, the main magnetic poles 2A and 2B of each phase are provided.
, The detent torque generated between the auxiliary magnetic pole 8 and the magnetic pole 9 of the inner peripheral surface, the detent torque generated between the auxiliary magnetic pole 8 and the magnetic pole 9 on the inner peripheral surface, and the detent torque generated at the main magnetic pole. Is shown in relation to the combined detent torque. The figure shows the detent torque acting on the rotor shaft when the rotor shaft is rotated from the outside while the winding is not energized by changing the rotation angle. M changes at a period twice as long as the magnetization pitch of the permanent magnet 6, and the detent torque DT-C generated at the auxiliary magnetic pole 8 also changes at twice the pitch of the magnetization pitch of the magnetic pole 9 on the inner peripheral surface. Moreover, DT-M generated at the main pole
And the DT-C generated by the auxiliary magnetic pole are 180 degrees out of phase, so that the combined total detent torque DT-A of the main magnetic pole and the auxiliary pole is canceled out to be almost zero.

FIG. 5 shows the relative positions of the main magnetic poles 2A, 2B of the stator, the magnetic poles of the permanent magnet 6 of the rotor, the auxiliary magnetic poles 8A, and the magnetic poles 9 of the inner peripheral surface, as in FIG. And
The A-phase main magnetic pole 2A and the B-phase main magnetic pole 2B have two bowl-shaped jackets, each main magnetic pole of which is arranged alternately, so that 2A, 2A ', 2B and 2B'. The pitches of the main magnetic poles 2A, 2A 'and 2B, 2B' are arranged at a pitch 1.5 times the pitch of the magnetic poles of the permanent magnet 6 of the rotor, and the relationship between the main magnetic poles 2A and 2B is They are arranged so as to have a half pitch. 4 with respect to FIG.
A, 2B and the relative position of the permanent magnet 6 of the rotor are the same, but the magnetic poles 9 on the inner peripheral surface of the permanent magnet 6 have the same pitch as the permanent magnet 6, but are provided shifted by 1/4 pitch. The difference is that the position of the magnetic pole 8 is arranged to be the same as the position of the main magnetic pole 2B. When the auxiliary magnetic pole 8 is arranged as shown in FIG. 5, the detent torque DT-M by the main magnetic poles 2A and 2B and the permanent magnet 6 is the same as in FIG. 4, but the position of the auxiliary magnetic pole 8 is different from that of the main magnetic pole 2B. Since they are arranged at the same position, the phase of the detent torque DT-C by the auxiliary magnetic pole 8 and the magnetic pole 9 on the inner peripheral surface becomes the same as the phase of the detent torque DT-M by the main magnetic pole. The detent torque of the magnetic pole and that of the auxiliary pole overlap, and the combined detent torque DT-A increases.

In the case of FIG. 4, the auxiliary magnetic poles 8 are arranged so that the main magnetic poles 2A and 2B substantially overlap with both the main magnetic poles 2A and 2B, so that the detent torque of each of the main magnetic poles and the auxiliary magnetic poles is reduced. Since the phases differ by 180 degrees, it is possible to obtain a desired combined detent torque by changing the logarithm, size, and the like of the auxiliary magnetic pole. Similarly, in the case of FIG. 5, since the auxiliary magnetic pole 8 is arranged at the same position as the position of the main magnetic pole 2B, the detent torques of the main magnetic pole and the auxiliary magnetic pole are in the same phase.
The desired combined detent torque can be obtained by changing the logarithm, the size, and the like of the auxiliary magnetic pole.

The configurations of FIGS. 1, 2 and 3 have been described for the case of the inner rotor type small motor in which the rotor is provided on the inner peripheral side of the stator. A stator member 2 in which a plurality of strip-shaped main magnetic poles are erected inward on an outer peripheral surface in a cylindrical shape and a cylindrical yoke is provided inside an end surface.
The two stators each having the bowl-shaped cylindrical yoke opposed to each other and arranged so that the respective strip-shaped main magnetic poles on the outer peripheral surface are alternately adjacent to each other, and the windings arranged on the outer periphery of the circular yoke are coaxially arranged. And a rotor mainly composed of a cylindrical permanent magnet in which N and S magnetic poles are alternately magnetized on the inner peripheral surface of the stator, which faces the outer peripheral surface of the stator via a gap, and rotates. In an outer rotor type small motor that is freely rotatably supported, N and S magnetic poles are alternately magnetized on the outer peripheral surface of the permanent magnet at the same pitch as the inner peripheral surface thereof, and the outer peripheral surface of the permanent magnet and the outer peripheral surface are appropriately spaced through a gap. A number of auxiliary magnetic poles are provided on the stator member and can be applied to the outer rotor type small electric motor. The arrangement of the auxiliary magnetic poles is the same as in the case of the inner rotor type electric motor.

[0011]

According to the present invention, since the small motor according to the present invention has the above-described configuration, the arrangement of the auxiliary magnetic poles provided on the stator allows the magnitude of the detent torque at the time of stopping power supply to be a desired magnitude. There is an effect that can be configured, and it is possible to easily obtain a small electric motor whose characteristics at the time of stoppage are suitable for the purpose of use.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a small electric motor according to the present invention.

FIG. 2 is a perspective view showing an overview of a permanent magnet rotor used in the small electric motor according to the present invention.

FIG. 3 is a perspective view showing an example of a stator member of the small electric motor according to the present invention.

FIG. 4 is a development view illustrating a state of generation of a detent torque in the embodiment of the small electric motor according to the present invention.

FIG. 5 is a development view illustrating a state of generation of a detent torque in another embodiment of the small electric motor according to the present invention.

FIG. 6 is a cross-sectional view showing the structure of a small electric motor according to the related art.

FIG. 7 is a perspective view showing an overview of a permanent magnet rotor used in a small electric motor according to the related art.

[Explanation of symbols]

 1A, 1B Stator jacket 2A, 2B Main magnetic pole 3A, 3B Coil bobbin 4A, 4B winding 5 Bearing 6 Permanent magnet rotor 7 Rotor shaft 8A, 8B Auxiliary magnetic pole 9 Inner magnetic pole of permanent magnet rotor

Claims (6)

[Claims] 1. A stator member having a plurality of rectangular main magnetic poles rising in a cylindrical shape inwardly from the bottom surface of a bowl-shaped stator casing, and the edges of the bowl shape are abutted against each other. A stator in which two strip-shaped main magnetic poles are arranged so as to cross each other, and two stators in each of which a winding is disposed on the outer circumference of the cylindrically-shaped strip-shaped main magnetic pole are coaxially connected; In a small motor in which a rotor mainly composed of a cylindrical permanent magnet in which N and S magnetic poles are alternately magnetized is rotatably supported on the outer peripheral surface of the stator facing the inner peripheral surface of the stator via a gap, N and S magnetic poles are alternately magnetized on the inner peripheral surface of the permanent magnet at the same pitch as the outer peripheral surface, and an appropriate number of auxiliary magnetic poles are provided to the stator member via the inner peripheral surface of the permanent magnet and the gap. A small electric motor. 2. Two stator members each having a plurality of strip-shaped main magnetic poles erected in an inward direction on the outer peripheral surface of a bowl-shaped stator jacket and having a cylindrical yoke provided inside the end surface. The bowl-shaped cylindrical yoke is abutted against each other, and the respective strip-shaped main magnetic poles on the outer peripheral surface are arranged alternately adjacent to each other, and two stators having windings arranged on the outer periphery of the circular yoke are coaxially arranged. A stator arranged and connected, facing the outer peripheral surface of the stator via a gap,
In an outer rotor type small motor in which a rotor mainly composed of a cylindrical permanent magnet in which N and S magnetic poles are alternately magnetized on its inner peripheral surface is rotatably supported, an outer peripheral surface of the permanent magnet is provided on an outer peripheral surface of the permanent magnet. N and S magnetic poles are alternately magnetized at the same pitch as
An outer rotor type small electric motor, wherein an appropriate number of auxiliary magnetic poles are provided on the stator member via a gap between the outer peripheral surface of the permanent magnet and the air gap. 3. The auxiliary pole is １ ／ of the pitch of the main pole.
The small electric motor according to claim 1, wherein the small electric motor is provided in a pair of pitches. 4. The outer rotor type small electric motor according to claim 2, wherein said auxiliary magnetic poles are arranged in pairs having a pitch of 1/2 of a main magnetic pole. 5. The small electric motor according to claim 3, wherein the auxiliary magnetic pole is arranged at a position crossing a main magnetic pole on the same side of each of the two stators. 6. The outer rotor type small electric motor according to claim 4, wherein the auxiliary magnetic pole is arranged at a position crossing a main magnetic pole on the same side of each of the two stators.