JP2003189567A - Synchronous reluctance motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a small-sided motor at a low cost which can obtain large torque at a low rotational speed region, and obtain a motor which can restrain rotation irregurality of a photosensitive drum without increasing size and cost of an image processor. <P>SOLUTION: This synchronous reluctance motor 10 has outer rotor structure which is equipped with a stator 12, a rotor 30 and a slit group 34, and is suitable for a low speed motor having large torque wherein rotational inertia force of the rotor 30 is large. In the stator 12, a coil 22 is wound around a plurality of slots 20 which are arranged radially and opened outward. The rotor 30 has a cylindrical rotor core 32 composed of magnetic substance, and the rotor core 32 is rotatably arranged outside the radial direction of the stator 12. The slit group 34 consists of a plurality of concentrically circular arc type slits 36 which are arranged at an equal interval along the peripheral direction of the rotor are core 32 and recessed on the axial line side of the stator 12. <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 synchronous reluctance motor, and more particularly to a synchronous reluctance motor preferably applied as a driving means for driving a photosensitive drum of an image processing apparatus.

[0002]

2. Description of the Related Art For example, an image processing apparatus (image forming apparatus) such as a color copying machine or a color printer is provided with four-color (black, yellow, blue, red) photosensitive drums, respectively. The drum is low speed (40 rpm to 1
00 rpm). For this reason, it is desired that the driving unit that rotationally drives the photosensitive drum does not cause rotational unevenness at a low rotational speed.

As a drive system for rotationally driving the four photosensitive drums, a system in which one photosensitive drum is mechanically synchronously rotated by using one motor (hereinafter referred to as a one-motor system)
There is a direct drive system (hereinafter, referred to as a 4-motor system) in which each photosensitive drum is provided with a driving motor.

As a one-motor system, for example, Japanese Patent Laid-Open No. 20
As disclosed in Japanese Patent Laid-Open No. 00-267373, there is a method in which one timing belt is wound around a timing pulley provided on each photosensitive drum and a timing pulley provided on an output shaft of a motor. Further, as another example of the one-motor system, as shown in FIG.
00 each include a gear portion 102, and the gear portion 102
There is a system in which the rotation of the motor M is transmitted to each photosensitive drum 100 via.

However, in the one-motor system as described above, uneven rotation is likely to occur due to variations in the tooth pitch of the timing belt and the accuracy of the gear pitch in the gear portion 102, and this uneven rotation causes deterioration of the image.

On the other hand, in the 4-motor system, it is necessary to employ a flat type motor in order to dispose the motor in a narrow space on the back surface of each photosensitive drum. However, when trying to realize such a flat type motor with a magnet type DC motor, there is a problem that sufficient torque cannot be obtained because the axial length of the magnet is limited.

If a rare earth magnet is used as a magnet for improving the torque, it will cause a high cost of the motor. Further, as disclosed in Japanese Patent Laid-Open No. 2-227271, a configuration in which an ultrasonic motor is provided as a motor arranged in the small space has been considered, but this also causes a high cost. Particularly, in the 4-motor system, since four motors are provided, the cost increase of each motor has a great influence on the cost of the image processing apparatus as a whole.

[0008]

SUMMARY OF THE INVENTION In consideration of the above facts, the first object of the present invention is to obtain a motor which is small in size, low in cost, and capable of obtaining a high torque in a low rotation speed range.

A second object of the present invention is to obtain a motor capable of suppressing uneven rotation of the photosensitive drum without increasing the size and cost of the image processing apparatus.

[0010]

In order to achieve the first object, a synchronous reluctance motor according to the invention of claim 1 is provided with a plurality of slots that are radially arranged and open outwardly. A stator having a winding wound around it, and a cylindrical rotor core made of a magnetic material,
A rotor in which the rotor core is rotatably arranged on the outer side in the radial direction of the stator, and a plurality of substantially concentric arcuate slits provided in the rotor core along the circumferential direction and each of which is concave on the axial center side of the stator. And a group of slits.

In the synchronous reluctance motor according to the first aspect, a flux barrier is formed by air in each slit or a high magnetic resistance material filled in each slit, and a magnetic pole center (d-axis) is formed between adjacent slit groups. ). When a field current is applied to the winding corresponding to the center of the magnetic poles (q-axis), magnetic flux is formed along the divided magnetic paths formed between the slits of the rotor core made of a magnetic material, and between the slit groups. A magnetic pole is formed. When a torque current is applied to the winding corresponding to the center of the magnetic pole, torque is generated and the rotor core, that is, the rotor rotates.

Such a synchronous reluctance motor is compact and has high torque characteristics in a low rotation speed range. Further, since the rotor core provided on the radially outer side of the stator has a so-called outer rotor structure,
It is suitable as a low-speed and high-torque motor with a large rotary inertia force.

In particular, in the structure in which the flux barrier is formed of air, the rotor core having the concave slit group on the axial center side has a large gap on the inner peripheral side, so that the weight on the outer peripheral side of the rotor core is relatively large. The motor can be large and lightweight as a whole, but has a large rotary inertia force.

Further, since the synchronous reluctance motor does not use a permanent magnet, it is not necessary to use an expensive rare earth magnet to obtain a high torque, and it is also necessary to use an expensive vibrator like an ultrasonic motor. No, the cost is low.

As described above, in the synchronous reluctance motor according to the first aspect, it is possible to obtain a high torque in a low rotation speed range with a small size and a low cost.

A synchronous reluctance motor according to a second aspect of the present invention is the synchronous reluctance motor according to the first aspect, wherein the rotor is adjacent to a support member rotatably supported by the stator and the rotor core. It is characterized by comprising mounting holes provided between the slit groups and a fixing member provided in the mounting holes for fixing the rotor core and the support member.

In the synchronous reluctance motor according to the second aspect, the rotor core is directly or indirectly fixed to the support member rotatably (freely) supported by the stator by the fixing member provided in the mounting hole. As a result, in the rotor, the rotor core is rotatably supported via the support member.

Here, since the mounting holes for mounting the fixing members (for example, bolts and screws) are provided between the plurality of slit groups, in other words, the portions where the flux barrier is not formed in the rotor core (the above-mentioned voids). Since the mounting hole is provided by utilizing the portion having a small number), the mounting hole can be provided by utilizing the portion having good strength without increasing the diameter of the rotor core (that is, the rotor).

A synchronous reluctance motor according to a third aspect of the present invention is the synchronous reluctance motor according to the second aspect, wherein the synchronous reluctance motor is rotatably supported in a through hole provided in an axial center portion of the stator. An output shaft coaxially connected to the support member is provided.

In the synchronous reluctance motor according to the third aspect of the present invention, the output shaft is coaxially connected to the support member to which the rotor core is fixed, and the output shaft is rotatably supported in the through hole of the stator. Therefore, it is not necessary to provide a bearing outside the rotor or the stator in the axial direction, and the axial dimension is small. That is, a bearing structure such as a bearing can be arranged in the through hole, or a bearing member such as a bearing can be arranged in the through hole, so that the synchronous reluctance motor becomes thin.

A synchronous reluctance motor according to a fourth aspect of the present invention is any one of the first to third aspects.
In the synchronous reluctance motor according to the paragraph, a base portion is provided on the stator so as to face an end surface of the rotor, is fixed to a predetermined position in a non-rotatable manner, and is provided on the rotor side of the base portion. A substrate on which a power supply circuit for the winding is formed, a sensor plate provided on an end surface of the rotor facing the substrate, and a position corresponding to the sensor plate of the substrate are provided to rotate the sensor plate. And a rotation detector that detects and outputs the detection result to the power feeding circuit via a control unit.

In the synchronous reluctance motor according to the fourth aspect, the rotation detector detects the rotation speed or rotation speed of the sensor plate (that is, the rotor) provided on the rotor and outputs the detection result to the power supply circuit. In the power supply circuit, for example, a current or frequency is controlled so that the rotor speed matches the set speed based on the detection result and the actual output to the winding.

Here, a rotation detector is provided at a position corresponding to the sensor plate (end face of the rotor) on the substrate on which the power feeding circuit is formed, and this substrate is provided on the rotor side of the base for mounting the stator which faces the rotor. Therefore, the synchronous reluctance motor integrally provided with the rotation detector becomes thin as a whole.

In order to achieve the second object, claim 5
The described synchronous reluctance motor is a synchronous reluctance motor that is directly connected to a photosensitive drum of an image processing apparatus and rotationally drives the photosensitive drum, and a stator having windings wound around a plurality of radially arranged slots. And a rotor core provided with a plurality of slit groups, each of which is made of a magnetic material and has a plurality of substantially concentric arcuate slits that are concave on the stator side, provided along the circumferential direction.

In the synchronous reluctance motor according to claim 5, a flux barrier is formed by air in each slit or a high magnetic resistance material filled in each slit, and a magnetic pole center (d-axis) is formed between adjacent slit groups. ). When a field current is applied to the winding corresponding to the center of the magnetic poles (q-axis), magnetic flux is formed along the divided magnetic paths formed between the slits of the rotor core made of a magnetic material, and between the slit groups. A magnetic pole is formed. Then, when a torque current is applied to the winding corresponding to the center of the magnetic pole, torque is generated and the rotor core rotates.

Such a synchronous reluctance motor is compact and has high torque characteristics in a low rotation speed range. For this reason, even if it is directly connected to the photosensitive drum of the image processing apparatus, the photosensitive drum can be rotationally driven with sufficient torque, and the image processing apparatus does not become large.

Further, since the synchronous reluctance motor does not use a permanent magnet, it is not necessary to use an expensive rare earth magnet to obtain a high torque, and it is also necessary to use an expensive vibrator like an ultrasonic motor. No, the cost is low. That is, the cost of the image processing device is not increased.

When the compact and high-torque synchronous reluctance motor is directly connected to the photosensitive drum as described above, it is not necessary to transmit the rotation of the motor to the photosensitive drum via a gear, a belt or the like. The unevenness is suppressed and the image quality is improved.

Particularly, if the synchronous reluctance motor is the synchronous reluctance motor according to any one of claims 1 to 4, a structure suitable for low rotation speed and high torque can be obtained, and size reduction in both radial and axial directions can be achieved. It is possible because it is possible.

As described above, in the synchronous reluctance motor according to the fifth aspect, it is possible to suppress the uneven rotation of the photosensitive drum without increasing the size and cost of the image processing apparatus.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION A synchronous reluctance motor 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3, and then an application example of the synchronous reluctance motor 10 to an image processing apparatus will be described with reference to FIG. It will be described based on.

FIG. 1 shows the entire structure of the synchronous reluctance motor 10 in a side sectional view, and FIG. 2 shows the stator 12 and the rotor core 32 of the rotor 30 which constitute the synchronous reluctance motor 10 in the axial direction. It is shown in a right-angled sectional view.

As shown in these figures, the stator 12
Is provided with a stator core 14,
Is a shaft hole 16 as a through hole provided in the shaft center portion thereof.
And a plurality of teeth (24 in the present embodiment) teeth 18 as salient poles radially extending outward from the axial center portion. Between the teeth 18, slots 20 that are open outward (radially outward) are radially formed.

Further, the stator 12 has a coil 22 as a winding. The coil 22 is wound around each slot 20 of the stator core 14.

At one axial end of the stator 12, a flat plate-shaped stator housing 24 as a base extending in a direction orthogonal to the axial direction is integrally provided separately from the end of the coil 22. There is. Stator housing 24
When the synchronous reluctance motor 10 is used, the stator 12 is non-rotatably fixed to a predetermined portion (for example, the casing 78 of the image processing apparatus described later). The shaft hole 16 is provided so as to penetrate through the stator housing 24 as well.
Includes a bearing 26 as a bearing coaxially arranged near both ends inside the shaft hole 16 of the stator core 14. The bearings 26 are used to support the output shaft 56, which will be described later.

A rotor 30 is provided radially outside the stator 12.
And the rotor 30 includes a rotor core 32. The rotor core 32 is formed in a substantially cylindrical shape as a whole by stacking a large number of annular thin plates (not shown) made of a magnetic material (high magnetic permeability material) in the axial direction.

The rotor core 32 is provided with a plurality of slit groups 34 penetrating in the axial direction (formed by punching each annular thin plate) at equal intervals along the circumferential direction. Each slit group 34 has a rotor core 3
A plurality of arcuate slits 36, which are concave on the axial center side of the stator 12 having the proximal end and the end near the inner peripheral surface of 2, are provided so as to be spaced apart from each other in the radial direction (substantially concentrically). ing.

Each slit group 34 is a void,
The inside of each slit 36 is filled with air acting as a high magnetic resistance material (low magnetic permeability material) to form a flux barrier. As a result, the arcuate portion of the high permeability material left between the slits 36 in the rotor core 32 becomes the divided magnetic path 38.

When a current (field current) is applied to the coil 22 in the axial (q-axis shown in FIG. 2) direction connecting the common arc center of each slit 36 and the axial center of the rotor core 32 (stator core 14). Due to the presence of the flux barrier, a magnetic flux is formed along the divided magnetic path 38 made of a high magnetic permeability material, and a magnetic pole is formed in the central portion between the slit groups 34. In this embodiment, the group of eight slits 34 is provided, and the rotor core 32 has eight poles. Further, in FIG. 1, the illustration of the slit group 34 (slit 36, divided magnetic path 38) is omitted.

With this structure, the q-axis becomes the center of the pole (center of the magnetic pole) and the central portion between the slit groups 34 becomes the center of the pole (center of the magnetic pole), and the magnetic pole is formed as described above. In this state, when a current (torque current) is applied to the coil in the direction of the axis (d-axis shown in FIG. 2) that connects the pole center and the axial center of the stator core 14, torque is generated and the rotor core 32 (rotor 30) operates. It has a rotating structure. That is, by providing the flux barrier by the slit group 34, the d-axis inductance is large and the q-axis inductance is small (or the d-axis reactance is q.
It becomes larger than the reactance of the shaft), so that the generated torque is obtained.

Further, the rotor core 32 is provided with mounting holes 40 penetrating in the axial direction at equal intervals at four positions between the adjacent slit groups 34, and is fixed to a rotor housing 42 as a supporting member. It is said that.

The rotor housing 42 is formed in a bottomed cylindrical shape (cup shape), the inner diameter of which corresponds to the outer diameter of the rotor core 32, and the depth (height inside the peripheral wall) of the rotor housing 32 in the axial direction. Is slightly larger than The rotor housing 42 has a bottom portion 42A on which the rotor core 3 is mounted.
Four screw holes 44 provided corresponding to the two mounting holes 40
have.

The rotor 30 has a fixing plate 46.
Is equipped with. The fixing plate 46 includes the rotor core 32.
It is formed in a ring shape having inner and outer diameters substantially corresponding to the inner and outer diameters of 4 and has four mounting holes 48 provided corresponding to the mounting holes 40 of the rotor core 32. Each mounting hole 48 has a taper shape (counterbore spot) corresponding to the head of a countersunk screw 50 described later over the entire axial length thereof.

The rotor core 32 is housed in the rotor housing 42. In the rotor core 32, the fixing plate 46 is in contact with the end surface on the other end side in a state where the end surface on the one end side in the axial direction is in contact with the bottom portion 42A of the rotor housing 42. In this state, the rotor core 32, the rotor housing 42, and the fixing plate 46 are fixed by countersunk screws 50 as a fixing member.

Specifically, the mounting hole 40 of the rotor core 32
The head of the countersunk screw 50 penetrating therethrough engages with the taper surface of the mounting hole 48 of the fixing plate 46, and the screw portion at the tip of the countersunk screw 50 is screwed into the screw hole 44 of the rotor housing 42, so that the rotor core 32, the rotor housing 42, and the fixing plate 46 are fixed. As a result, a large number of annular thin plates forming the rotor core 32 are also fixed.

As described above, by using the countersunk screw 50 as the fixing member, the above fixing is performed by the thin-walled fixing plate 46 without the head of the countersunk screw 50 protruding, and the rotor 30 (that is, the synchronous reluctance). The motor 10) is thinned as a whole.

A boss 54 having an output shaft hole 52 is provided at the axial center of the rotor housing 42.
An output shaft 56 is integrally rotatably connected to the output shaft hole 52 of the boss 54 by fitting or the like. This output shaft 56 is
The bearing 26 is rotatably supported by the bearing 26 while being inserted into the shaft hole 16 of the stator 12 (stator core 14).

That is, the rotor 30 (rotor core 32)
Are rotatably supported by the stator 12. In this state, the tips of the teeth 18 of the stator 12 and the rotor core 3 are
2 A predetermined gap G is formed between the inner peripheral surface (near the base end and the end of each slit 36). A recess 42B is formed between the boss 54 in the bottom portion 42A of the rotor housing 42 and the rotor core 32 housing portion.
It does not interfere with the coil 22 when the rotor 30 rotates.

An encoder plate 58 as a sensor plate having substantially the same shape is attached to the end surface of the fixing plate 46 in the fixed state on the side of the stator housing 24 by adhesion or the like. The encoder plate 58 constitutes a reflection type photo encoder together with a sensor element as a rotation detector described later.

In addition, the synchronous reluctance motor 1
In No. 0, a power supply control circuit for energizing the coil 22 is integrally provided. The power feeding control circuit is a circuit in which a control portion is added to the power feeding circuit of the present invention.
It is formed on a substrate 60 attached to the surface of the stator housing 24 facing the rotor 30. This power supply control circuit, for example, performs a sinusoidal PWM modulation of a DC voltage (current) supplied to a connector 62 provided on the substrate 60, and supplies power from the output unit 64 to the coil 22 via the power supply line 66 in a three-phase AC approximate manner. Is supposed to do.

That is, the synchronous reluctance motor 10 is a multi-phase synchronous reluctance motor, and has three phases in this embodiment. Since the rotational speed (that is, the synchronous speed) of the synchronous reluctance motor 10 is proportional to the frequency of power supply, power supply frequency control is necessary to maintain a constant rotation speed.

This power supply frequency control is also performed by the power supply control circuit, but in order to detect the actual rotation speed, the synchronous reluctance motor 10 has a sensor element 68 as a rotation detector. The sensor element 68 is a substrate 60.
One or more are provided at a position corresponding to the rotation trajectory of the encoder plate 58 of the rotor 30 above, the rotation speed or rotation speed of the encoder plate 58 (that is, the rotor 30) is detected, and the detection result is supplied to the power supply control circuit. It is a structure to feed back to.

In this embodiment, the substrate 60 is screw 6
Although it is fixed to the stator housing 24 by means of screwing with 9, the substrate 60 may be attached to the stator housing 24 by adhesion or the like.

Next, the operation of this embodiment will be described.

In the synchronous reluctance motor 10 having the above-described structure, the DC voltage supplied to the connector 62 is sine-wave PWM modulated by the power supply control circuit, and the coil 22 is supplied with power of approximately three-phase AC.

Then, a magnetic pole is formed by the field current flowing through the coil 22 in the q-axis direction, and a torque is generated by the torque current flowing through the coil 22 in the d-axis direction, which is the pole center of the magnetic pole. 30 rotates around the stator 12.

At this time, the sensor element 68 is the rotor 30.
The rotation speed of is detected and fed back to the power supply control circuit. The power feeding control circuit appropriately controls the power feeding frequency to maintain the rotation speed of the rotor 30 at the set rotation speed.

Here, in the synchronous reluctance motor 10, the torque-rotational speed characteristic as shown by the solid line in FIG. 3 is obtained. As can be seen from this characteristic diagram, the synchronous reluctance motor 10 can obtain a large torque at a low rotation speed. The characteristic indicated by the broken line in FIG. 3 is the torque-rotational speed characteristic of the DC motor having the same physical structure shown for comparison.

In addition, the synchronous reluctance motor 1
0 is a rotor 3 provided outside the stator 12 in the radial direction.
Since it has a so-called outer rotor structure in which 0 (rotor core 32) rotates, the rotary inertia force is large (the influence of load fluctuation is small), and it is suitable as a low-speed and high-torque motor.
In particular, since the flux barrier is formed with each slit 36 as an air gap, in other words, since the rotor core 32 has a structure with many air gaps on the inner peripheral side, the rotor core 32 has a relatively large weight on the outer peripheral side and the whole rotor core 32 has a large weight. As a result, a motor having a large rotary inertia force while being lightweight is configured, which is more preferable.

Further, the synchronous reluctance motor 10 is constructed as described above, and since it does not use a permanent magnet, it is not necessary to use an expensive rare earth magnet to obtain high torque, and it is expensive like an ultrasonic motor. There is no need to use a vibrator, resulting in low cost.

As described above, in the synchronous reluctance motor 10 according to the present embodiment, it is possible to obtain a high torque in a low rotation speed range with a small size and a low cost.

Since the rotor core 32 is provided with the mounting hole 40 between the adjacent slit groups 34,
In other words, since the mounting hole 40 is provided by utilizing the portion where the flux barrier is not formed, the rotor core 3
The mounting hole can be provided by utilizing the portion having good strength (the portion having few voids) without increasing the diameter of 2.

Further, in the synchronous reluctance motor 10, the output shaft 56 is coaxially connected to the rotor housing 42 to which the rotor core 32 is fixed, and the output shaft 56 is the bearing 26 in the shaft hole 16 of the stator 12.
Since the shaft is rotatably supported by, the axial dimension can be significantly reduced as compared with the configuration in which the bearing is provided outside the axial end of the rotor 30 or the stator 12. That is, the synchronous reluctance motor 10 is thinned as a whole.

Furthermore, in the synchronous reluctance motor 10, the end surface of the rotor 30 (encoder plate 58) on the substrate 60 provided in the stator housing 24.
The synchronous reluctance motor 10 integrally provided with the rotation control function (power supply frequency control function by the power supply control circuit) is provided because the sensor element 68 forming the reflection type photo encoder is provided at a position facing the Be converted.

Next, an example in which the synchronous reluctance motor 10 having the above configuration is applied to an image processing apparatus (image forming apparatus) such as a color printer or a color copying machine will be shown.

As shown in FIG. 4, the image processing apparatus comprises four photosensitive drums 7 corresponding to red, blue, yellow and black, respectively.
0, 72, 74, 76 are provided. Each photosensitive drum 7
0, 72, 74, 76 rotate about the axis,
The formed toner images corresponding to the respective colors are transferred to the transfer body.

A synchronous reluctance motor 10 as a rotation driving means is connected to each of the photosensitive drums 70, 72, 74 and 76. Specifically, the output shaft 56 of the synchronous reluctance motor 10 is directly connected to the photosensitive drums 70, 72, 74 and 76.

Each synchronous reluctance motor 10
Have their respective stator housings 24 fixed to a casing 78 of the image processing apparatus, and when the coil 22 is energized, the rotor 30 rotates in a predetermined direction to rotate the photosensitive drums 7.
The configuration is such that 0, 72, 74 and 76 are rotationally driven.

Here, since the synchronous reluctance motor 10 has a characteristic that it is small and generates a high torque in a low rotation speed region as described above, even if it is directly connected to the photosensitive drum 70 of the image processing apparatus, The drum 70 and the like can be rotationally driven with sufficient torque, and the image processing apparatus is not upsized. In particular, since the synchronous reluctance motor 10 is thinned (flattened) as described above, it is preferably arranged in a narrow space on the back surface (axial end) of each photosensitive drum 70 or the like.

In addition, the synchronous reluctance motor 1
Since the cost of 0 is reduced as described above, the cost of the image processing apparatus is not increased.

When the compact and high-torque synchronous reluctance motor 10 is directly connected to the photosensitive drum 70 or the like, it is not necessary to rotate the photosensitive drum 70 or the like through a gear or a belt, so that the photosensitive drum 70 or the like is not required. Rotational unevenness is suppressed and the image quality is improved. That is, the accuracy of the image processing device can be improved.

As described above, the photosensitive drum 7 of the image processing apparatus is
In the synchronous reluctance motor 10 that is directly connected to the photosensitive drum 70 or the like and rotates and drives the photosensitive drum 70 or the like, the photosensitive drum 70 is not increased in size and cost of the image processing apparatus.
It is possible to suppress irregular rotation of the vehicle.

In the application example of the synchronous reluctance motor to the image processing apparatus, the preferable example in which the outer reluctance reluctance motor 10 having the outer rotor structure is directly connected to each photosensitive drum 70 is shown, but the present invention is not limited to this. Instead, for example, a synchronous reluctance motor 8 having an inner rotor structure according to a modification as shown in FIG.
0 may be directly connected to each photosensitive drum 70 or the like.

In the synchronous reluctance motor 80, a plurality of (in this modification, 36) teeth 84 are provided on the inner peripheral portion of a cylindrical stator core 82. The stator is configured by winding the coil 22 around the slots 86 formed radially between the teeth 84 of the stator core 82.

On the other hand, the rotor core 88 is formed in a cylindrical shape as a whole by laminating a plurality of annular thin plates made of a magnetic material (high magnetic permeability material) in the axial direction, and a shaft hole 88A provided in the shaft center portion thereof. The output shaft 56 is fixed to. The rotor core 88 is provided with a plurality of slit groups 90 that form a flux barrier. In each slit group 90, a plurality of arc-shaped slits 92, which are concave (convex toward the axial center) on the side of the stator core 82 whose proximal end and the end are near the outer peripheral surface of the rotor core 88, are separated from each other in the radial direction ( (Substantially concentrically) provided.

The arcuate portion left between the slits 92 in the rotor core 88 serves as a divided magnetic path 94, the pole center (d axis) lies between the slit groups 90, and the central portion of each slit group 90 serves as a pole. It is the same as that of the synchronous reluctance motor 10 in that it becomes the center (q axis).

The rotor core 88 is the stator core 82.
The output shaft 56 is rotatably supported by a bearing (not shown) in a state where the output shaft 56 is coaxially housed in the interior of the stator core 82, thereby forming a gap G between the output shaft 56 and the stator core 82.

This synchronous reluctance motor 80
Is a configuration in which the generated torque is obtained by energizing the coil 22 similarly to the synchronous reluctance motor 10. In this modified example, four slit groups 90 are provided, and the rotor core 88 has four poles.

Even in the configuration in which the synchronous reluctance motor 80 according to the present modification is directly connected to each photosensitive drum 70 of the image processing apparatus, the synchronous reluctance motor 80 is small in size and has a high torque characteristic in a low rotation speed range. The photosensitive drum 70 and the like can be rotationally driven with sufficient torque, and the image processing apparatus is not upsized.

In addition, the synchronous reluctance motor 8
0, like the synchronous reluctance motor 10,
Since there is no need to use expensive rare earth magnets or vibrators,
The cost can be reduced, and the cost of the image processing apparatus is not increased.

When the compact and high-torque synchronous reluctance motor 80 is directly connected to the photosensitive drum 70 or the like as described above, it is not necessary to transmit the rotation to the photosensitive drum 70 or the like through a gear, a belt or the like. Rotational irregularity such as 70 is suppressed, and the image quality is improved.

In the above-described embodiment and modification,
Although the flux barrier is formed by the voids (air) formed by the slit groups 34 and 90, the present invention is not limited to this, and for example, the slits 36 such as the slit group 34.
The flux barrier may be formed by a high magnetic flux resistance material filled in the inside of the above.

Further, in the above-mentioned embodiment and modification,
Although the rotor cores 32 and 88 (a plurality of annular thin plates forming the rotor cores) are fixed to the rotor housing 42 by the flat head screws 50, the present invention is not limited to this. The rotor core 32 and the like fixed in a laminated state to the rotor housing 42 by adhesion or the like.
It may be configured to be fixed to.

Further, in the above embodiment, the output shaft 5
6 is rotatably supported by the bearing 26,
The present invention is not limited to this, and for example, the output shaft 56 may be pivotally supported by a bearing portion that is in sliding contact with the output shaft 56 in a lubricated state. Further, the present invention is not limited to the preferable configuration in which the bearing portion and the bearing 26 are provided in the shaft hole 16.

Furthermore, in the above-described embodiment, the power feeding control circuit has both the power feeding function and the control function, but the present invention is not limited to this, and the power feeding circuit and the control circuit are separately provided. It may be provided (for example, it goes without saying that the case where the control circuit is not provided on the substrate 60 is included).

Further, the present invention is not limited to the preferable structure provided integrally with the substrate 60 provided with the power supply control circuit, and the preferable structure provided with the reflection type photo encoder as the rotation detector. Further, according to the present invention, the number of slit groups 34, 90 (that is, the number of poles) in the rotor cores 32, 88, the number of each slit 36, etc. constituting each slit group 34, etc. (flux barrier), the stator core 1
It goes without saying that the numbers of the teeth 18, 84 in the numbers 4, 92 are not limited to the numbers in the above-described embodiment and modification, respectively.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an overall configuration of a synchronous reluctance motor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view perpendicular to the axial direction showing a stator core and a rotor core that constitute the synchronous reluctance motor according to the embodiment of the present invention.

FIG. 3 is a diagram showing a torque-rotation speed characteristic of the synchronous reluctance motor according to the embodiment of the present invention.

FIG. 4 is a perspective view showing an application example of the synchronous reluctance motor according to the embodiment of the present invention to an image processing apparatus.

FIG. 5 is an axially perpendicular sectional view showing a stator core and a rotor core that constitute a synchronous reluctance motor according to a modification of the embodiment of the present invention.

FIG. 6 is a perspective view showing an example of a photosensitive drum driving structure in a conventional image processing apparatus.

[Explanation of symbols]

10 Synchronous reluctance motor 12 stator 14 Stator core (stator) 16 shaft hole (through hole) 20 slots 22 coil (winding) 24 Stator housing (base) 30 rotor 32 rotor core 34 slits 36 slits 40 mounting holes 42 rotor housing (support member) 50 Flat head screw (fixing member) 56 Output shaft 58 Encoder plate (sensor plate) 60 board (power supply circuit) 68 Sensor element (rotation detector) 70, 72, 74, 76 Photosensitive drum (image processing device) 80 Synchronous reluctance motor 82 Stator core (stator) 86 slots 88 Rotor core (rotor) 90 slits 92 slits

Claims (5)

[Claims] 1. A stator having windings wound around a plurality of slots that are radially arranged and open toward the outside, and a cylindrical rotor core made of a magnetic material, and the rotor core is the stator. A rotor rotatably arranged on the outer side in the radial direction, and a slit group formed of a plurality of substantially concentric arc-shaped slits provided in the rotor core along the circumferential direction, each of which is concave on the axial center side of the stator, Synchronous reluctance motor with. 2. The rotor includes a support member rotatably supported by the stator, an attachment hole provided between the slit groups adjacent to each other in the rotor core, the rotor core and the support provided in the attachment hole. 2. The synchronous reluctance motor according to claim 1, further comprising a fixing member that fixes the member. 3. An output shaft, which is rotatably supported in a through hole provided in an axial center portion of the stator and is coaxially connected to the support member. 2. The synchronous reluctance motor according to 2. 4. A base portion, which is provided on the stator so as to face the end surface of the rotor, for non-rotatably mounting the stator at a predetermined position, and a rotor portion of the base portion, A substrate on which a power supply circuit is formed, a sensor plate provided on an end surface of the rotor facing the substrate, a position corresponding to the sensor plate of the substrate, and detecting the rotation of the sensor plate. The rotation reluctance motor which outputs a result to the said electric power feeding circuit via a control part, The synchronous reluctance motor of any one of Claim 1 thru | or 3 characterized by the above-mentioned. 5. An image processing apparatus is directly connected to a photosensitive drum,
A synchronous reluctance motor that rotationally drives the photosensitive drum, comprising: a stator having windings wound in a plurality of radially arranged slots; and a plurality of magnets, each of which has a recess on the stator side. A synchronous reluctance motor comprising: a rotor core provided with a plurality of slit groups each having a concentric arcuate slit along the circumferential direction.