JP3060610B2 - Variable reluctance motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable reluctance motor, and more particularly, to a structure of a rotor.

[0002]

2. Description of the Related Art Conventionally, a variable reluctance motor has a stator in which coils are respectively wound around a plurality of magnetic pole projections provided on an inner peripheral portion, a rotatable support in a space surrounded by the stator, and an outer peripheral portion. And a rotor having a plurality of magnetic pole projections.

The operation principle of this motor will be described with reference to FIG. When the coil C is excited when the rotor R is positioned at the phase angle θA on the advance side shown by a solid line with respect to the stator S during the rotation driving, the magnetic path is widened to the rotor R to reduce the magnetic resistance, and the magnetic flux density is reduced. 7, a positive rotational torque is generated in the direction indicated by the arrow in FIG.

[0004] Such a state in which the magnetic resistance changes appears as a change in the self-inductance of the coil C. Therefore, when the coil C is energized in a region where the inductance increases, a positive rotational torque is generated in the rotor R. Also,
When the rotor R is positioned at a phase angle θB on the retard side shown by a broken line with respect to the stator S, and the self-inductance of the coil C changes in a decreasing direction by the rotation of the rotor R, the rotor R is energized. A negative rotation torque (braking torque) is generated in R.

As described above, the variable reluctance motor generates a positive or negative rotational torque by controlling the energization of the coil C at a predetermined rotor R position. The torque T is expressed by the following equation (1). Is done.

T = KI2 · dL / dθ (1) L: inductance of coil C θ: phase angle of rotor R I: current flowing in coil K: constant Variable reluctance motor having such torque characteristics In order to increase the torque, dL of the equation (1)
/ Dθ needs to be increased.

The inductance L is maximized at a phase angle where the magnetic pole projections of the rotor R and the magnetic pole projections of the stator S coincide with each other. When it is at a minimum.

The torque T increases as the difference between the maximum and minimum of the inductance L increases. To this end, at a phase angle at which the inductance L becomes the maximum, the gap between the magnetic pole protrusion of the rotor R and the magnetic pole protrusion of the stator S becomes smaller, thereby increasing the inductance L.

Next, at the phase angle at which the inductance L becomes the minimum, the larger the gap reduces the inductance L. That is, increasing the depth of the groove between the magnetic pole projections of the rotor R increases the torque T.

[0010]

However, when the rotor R rotates at a high speed, each magnetic pole projection is regarded as a blade of a windmill and a drag is generated.

Generally, when an object in a fluid moves, a force (drag) opposite to the moving direction is received, and the force D is expressed by the following equation (2).

D = CDυ2Aγ / 2g (2) CD: resistance coefficient υ: traveling speed of the object A: reference area of the object (maximum area perpendicular to the traveling direction) γ: specific weight of fluid g: gravity Acceleration Here, the drag D1 acting on the magnetic pole projections of the rotating rotor R regarded as a windmill is considered as shown in FIGS. 8 and 9. Therefore, from the above equation (2), D1 = CDυ2γZ (R0−R1 ) / 2g (3) Z: Product thickness of rotor R R0: Radius of circumscribed circle of rotor R R1: Radius of inscribed circle of rotor R Further, the air density ρ and the angular velocity ω of the rotor R are expressed by the following equations. It is represented as

Ρ = γ / g (4) ω = υ / R0 (5) From the equations (3), (4) and (5), D1 = CDρω2R02Z (R0−R1) / 2 (6) Since the drag D1 is a force acting on one magnetic pole projection regarded as a blade, a loss torque T acting on the rotor R having N poles is used.
N is given by the following equation (7).

TN = D1R0N = CDρω2R03NZ (R0−R1) / 2 (7) The loss torque TN is a main factor of windage loss, and the mechanical loss during high-speed rotation driving of the motor is reduced. Increase
Therefore, there has been a problem that the efficiency is reduced and the noise is also generated.

As a method for addressing such a problem, there is a case where (R0-R1) in the equation (7) is reduced, that is, the depth of the groove between the magnetic pole projections of the rotor R is reduced. As a result, the minimum value of the inductance L is increased, and accordingly, dL / dθ in the equation (1) is reduced, which causes a problem that the torque characteristics of the motor deteriorate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and provides a variable reluctance motor that reduces windage without deteriorating the torque characteristics of the motor, has high efficiency, and has low noise. The purpose is to do.

[0017]

In order to achieve this object, a variable reluctance motor according to claim 1 of the present invention is provided.
A stator in which a coil is wound around each of a plurality of magnetic pole protrusions provided on an inner peripheral portion, a rotor having a plurality of magnetic pole protrusions on an outer peripheral portion, and a magnetic pole protrusion between the respective magnetic pole protrusions of the rotor. A bridging portion extending toward adjacent magnetic pole protrusions ,
The intermediate portion of the bridge and the bottom of the groove between the magnetic pole projections
It has a connecting rib .

The variable relax according to claim 2 of the present invention.
The closet motor has a plurality of magnetic pole projections
A stator with coils wound around it and multiple
Rotor provided with magnetic pole projections, and magnetic poles of the rotor
Adjacent to each pole protrusion between the tip and center of the protrusion
It has a bridging portion extending toward the pole projection.

[0019]

According to the first and second aspects of the present invention having the above construction,
In the variable reluctance motor described above, a bridging portion extending from each magnetic pole protrusion of the rotor to an adjacent magnetic pole protrusion is
In order to reduce windage loss without deteriorating the torque characteristics of the motor, the motor is driven to rotate quietly and efficiently.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the internal configuration of the variable reluctance motor.

In FIG. 1, a six-pole magnetic pole projection 14 on which an annular coil 12 in which conductive wires are bundled is mounted is provided on an inner peripheral portion of a cylindrical stator 10 made of a laminated iron core.
On the other hand, in the cylindrical space surrounded by the stator 10,
Output shaft 16 and rotor core 1 supported on output shaft 16
8 is rotatably supported.
The rotor core 18 is configured by laminating an iron core forming plate 24 having four magnetic pole projections 22 on the outer peripheral portion. A bridge 26 is formed integrally with the outer periphery of the tip of each magnetic pole projection 22 of the rotor 20. And the bridge 2
6, the magnetic pole projections 22 are connected to each other, and the outer periphery of the rotor 20 is a perfect circle without any irregularities. Note that the bridge 26 can be easily formed by manufacturing the iron core forming plate 24 by punching such as a press.

Although not shown, a rotating disk having a slit on the outer periphery is fixed to the output shaft 16, and a photo-interrupter for detecting the slit is provided facing the rotating disk. The rotating disk and the photointerrupter constitute a rotational position detector, and the position of each magnetic pole projection 14 with respect to the rotor 20 can be obtained based on a detection signal from this detector.

Next, the operation of the motor will be described.

This motor is controlled based on the principle described in the prior art. For example, the magnetic pole projections 22a of the rotor 20 shown in FIG.
When the position approaches a (in a region where the inductance increases), this state is detected by the rotational position detector, and an energization command to the coil 12a is output from the electronic control unit (not shown) based on the detection signal. As a result, a positive rotation torque is generated in the rotor 20. And the magnetic pole projection 22 of the rotor 20
When a moves away from the magnetic pole protrusion 14a of the stator 10 (in a region where the inductance is reduced), the energization of the coil 12a is stopped and no negative rotational torque is generated, and the rotational torque in the positive direction is maintained. During braking, when the magnetic pole projection 22a of the rotor 20 moves away from the magnetic pole projection 12a of the stator 10, the coil 12a is energized to generate a braking force.

In the operation of the motor described above, the rotor 2
Since the width t of the bridge 26 of 0 is sufficiently smaller than the height y of the magnetic pole protrusion 22 of the rotor 20, the magnetic flux passing through the bridge 26 is magnetically saturated in a practical magnetomotive force region, and the inductance is reduced to reduce the groove. Is regarded as Therefore, the torque characteristics of the motor maintain the previous state.

Next, the drag generated when the rotor 20 is rotated at a high speed is not generated because the outer periphery of the rotor 20 has no irregularities and is a perfect circle. This means
In equation (7) shown in the problem to be solved by the invention, it is clear that TN = 0 by setting R0 = R1. Thus, windage loss is greatly reduced and mechanical loss is reduced.

Further, since there are no irregularities regarded as blades of the windmill, wind noise is not generated by the blades, so that noise can be reduced.

As another embodiment, the bridge 26 is connected to the rotor 2
The same effect as described above can be obtained by engaging another non-magnetic material as shown in FIG.

In this embodiment, each magnetic pole projection 22
Are connected to each other with a bridge 26 to make the whole rotor 20 a perfect circle. However, as shown in FIG. They may be combined.

Further, in this embodiment, the bridge 26 is formed in a circular arc in order to make the entire outer periphery of the rotor 20 a perfect circle, but it may be formed in a straight line as shown in FIG.

In this embodiment, each magnetic pole projection 22
5 are connected by a bridge 26.
As shown in FIG. 7, a part of the bridge 26 may be slightly separated, and the magnetic pole projections 22 may not be completely connected.

Further, in this embodiment, each magnetic pole projection 2
2 are connected with the bridge 26, but as shown in FIG. 6, the middle portion of the bridge 26 is connected to the bottom of the groove by one or more narrow ribs 28, so that the centrifugal force at the time of rotation drive is obtained. The bridge 26 may be reinforced.

[0034]

As is apparent from the above description, in the variable reluctance motor according to the first and second aspects of the present invention, between each magnetic pole projection and the adjacent magnetic pole projection. With the provision of the bridging portion, the windage loss when the motor is driven to rotate can be reduced, and the efficiency can be increased.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an internal configuration of a variable reluctance motor according to one embodiment of the present invention.

FIG. 2 is an explanatory sectional side view showing an internal configuration of a variable reluctance motor according to a first modified example of the present invention.

FIG. 3 is an explanatory diagram showing an internal configuration of a variable reluctance motor according to a second modified example of the present invention.

FIG. 4 is an explanatory diagram showing an internal configuration of a variable reluctance motor according to a third modified example of the present invention.

FIG. 5 is an explanatory diagram showing an internal configuration of a variable reluctance motor according to a fourth modification of the present invention.

FIG. 6 is an explanatory diagram showing an internal configuration of a variable reluctance motor according to a fifth modified example of the present invention.

FIG. 7 is an explanatory diagram showing the principle of a variable reluctance motor.

FIG. 8 is an explanatory diagram showing a principle of obtaining a drag acting on a rotor.

FIG. 9 is an explanatory diagram showing a principle of obtaining a drag acting on a rotor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Stator 12 Coil 14 Magnetic pole protrusion 16 Output shaft 18 Rotor core 20 Rotor 22 Magnetic pole protrusion 26 Bridge

Claims (2)

(57) [Claims] 1. A variable reluctance motor comprising: a stator having coils wound around a plurality of magnetic pole protrusions provided on an inner peripheral portion thereof; and a rotor having a plurality of magnetic pole protrusions provided on an outer peripheral portion thereof. between each pole protrusion, a bridge portion extending toward the pole protrusion adjacent from each pole protrusion, and a bottom of the groove between the respective magnetic poles projecting an intermediate portion of the bridge
A variable reluctance motor comprising a connecting rib . 2. A plurality of magnetic pole projections provided on an inner peripheral portion.
A stator wound with coils, And a rotor provided with a plurality of magnetic pole protrusions on an outer peripheral portion.
In a variable reluctance motor, Between the tip and the center of each pole projection of the rotor, each
A bridging portion extending from the magnetic pole protrusion to the adjacent magnetic pole protrusion
A variable reluctance motor comprising: