JP2016226094A - Control unit integrated electric drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control unit integrated electric drive device which improves detection angle accuracy, is downsized and lightweight and reduces torque ripple.SOLUTION: The control unit integrated electric drive device comprises a sensor magnet 9 which is fixed in one end of a shaft 6 that is supported in a freely rotatable manner in a housing 4, and integrated with a holder 10. The holder 10 is formed from a cylindrical nonmagnetic substance including a bottom face with a hole opened thereon in one end. The sensor magnet 9 is integrated at both sides of the bottom face of the holder 10 at the outer peripheral side by injection molding. The holder 10 and the sensor magnet 9 are disposed separately while being spaced from one end of the shaft 6, and a fixing portion of the holder 10 and the shaft 6 includes a circular contact surface.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control unit-integrated electric drive device in which a motor and a control unit mounted on an electric power steering device for a vehicle are integrated on the same axis of a motor output shaft.

  A semiconductor sensor used in a control unit-integrated electric drive device in which a motor and a control unit are integrated is mainly a magnetoresistive element, and is attached to the end of a shaft, which is a rotating shaft of the motor, via a holder. The rotating magnetic field of the motor magnet is detected, and the rotation angle of the motor is detected.

  Conventionally, as a method of holding a sensor magnet on a shaft, for example, as disclosed in Japanese Patent Application Laid-Open No. 2005-318687 (Patent Document 1), the end portion of the shaft is cut in the axial direction into a flat portion, A technique is known in which a sensor magnet having a center hole larger than this is inserted and fixed with a washer.

  As another method for holding the sensor magnet on the shaft, for example, as disclosed in Japanese Patent Application Laid-Open No. 2013-7731 (Patent Document 2), the sensor magnet is provided inside a holder having a magnetic material serving as a magnetic induction portion. A technique for holding a magnet and fixing the holder to the outer periphery of a shaft is known.

  Furthermore, as another method for holding the sensor magnet on the shaft, for example, as disclosed in Japanese Patent Application Laid-Open No. 2014-57431 (Patent Document 3), the sensor magnet is placed inside one end of a holder having a substantially cylindrical shape. A technique for fixing and fixing the other end to the outer periphery of the shaft is known.

JP 2005-318687 A JP 2013-7731 A JP 2014-57431 A

  The magnet for the sensor of the control unit-integrated electric drive unit that integrates the motor and the control unit mounted on the electric power steering device has structural issues such as being able to be fixed to the shaft with a simple structure, magnetizing the magnet There are problems from the manufacturing aspect such as easy orientation and parallel orientation, and problems from the functional and performance aspects such as small and light and small angle detection error.

  As for the structural surface, for example, as in Patent Document 1, providing a flat portion on the shaft increases the number of processing steps and processing time, and requires positioning and insertion of the shaft and the magnet for the sensor. There are problems such as increased capital investment.

  As for the manufacturing surface, for example, as in Patent Document 2, it is difficult to magnetize in the case of a magnet shape with a hole or a shaft penetrated with respect to the general parallel orientation of NS2 poles. When holding the magnet for the sensor, it must be magnetized with a large current between the magnetized yoke and the magnet via a gap and a holder, which requires equipment with high cooling performance against heat generation and tact. There are problems such as increased time.

  Furthermore, with regard to functional and performance aspects, for example, as in Patent Document 2, in the case where the sensor magnet has a hole, the magnetic field strength in the vicinity of the rotation axis is reduced, so the semiconductor sensor is disposed far away. There must be. For this reason, there exists a problem that the mounting property to a steering gear and the deterioration of a vehicle fuel consumption will arise by the enlargement and weight increase of an electric drive device. In addition, for example, as in Patent Document 3, in a holder made of complicated parts or a holder having a complicated shape, the sensor magnet is decentered or tilted, the angle error is deteriorated, and the steering feeling such as torque ripple is deteriorated. There's a problem.

  The present invention has been made to solve the above-described problems of the conventional apparatus, and an object of the present invention is to provide a control unit-integrated electric drive apparatus that is small and light and has a small torque ripple.

The control unit-integrated electric drive device according to the present invention includes a control unit that controls a motor unit arranged coaxially with an output shaft of the motor unit, and the control unit and the motor unit are integrated in the electric drive device. The portion includes a stator fitted to the inner periphery of the housing, a shaft rotatably supported by the housing, a rotor fixed to the shaft and facing the stator via a gap, and the shaft A sensor magnet fixed to one end opposite to the motor output side and integrated with the holder, rotation angle detection means for detecting the magnetic field of the sensor magnet, and the rotor detected by the rotation angle detection means A control unit that controls the motor unit according to the rotation angle of
The holder is made of a cylindrical non-magnetic material having a bottom surface with a hole at one end, and the sensor magnet is injection-molded and integrated on both sides and the outer peripheral side of the bottom surface of the holder, The holder and the magnet for sensor are arranged so as to be spaced apart from one end of the shaft via a gap, and the fixed portion of the holder with the shaft has a circular contact surface.

  According to the present invention, it is possible to provide a control unit-integrated electric drive apparatus having a small size and light weight and a small torque ripple.

It is sectional drawing which shows the control unit integrated electric drive device by Embodiment 1 of this invention. It is sectional drawing which shows the magnet for sensors and the holder of the control unit integrated electric drive device by Embodiment 1 of this invention. It is sectional drawing which shows the magnet for sensors and the holder of the control unit integrated electric drive device by Embodiment 2 of this invention. It is a figure which shows the increase rate of the magnetic field intensity per 1 mm of air gaps, and the air gap distance of the magnet for sensors of the control unit integrated electric drive device by Embodiment 2 of this invention, and a shaft end surface. It is sectional drawing which shows the magnet for sensors and the holder of the control unit integrated electric drive device by Embodiment 3 of this invention. It is sectional drawing which shows the example from which the magnet for sensors and a holder of the control unit integrated electric drive device by Embodiment 3 of this invention differ. It is sectional drawing which shows the other Example from which the magnet for sensors and a holder of the control unit integrated electric drive device by Embodiment 3 of this invention differ. It is sectional drawing which shows the other Example from which the magnet for sensors and a holder of the control unit integrated electric drive device by Embodiment 3 of this invention differ. It is sectional drawing of the magnet for sensors and the holder of the control unit integrated electric drive device by Embodiment 4 of this invention. It is sectional drawing which shows the Example from which the magnet for sensors of the control unit integrated electric drive device by Embodiment 4 of this invention and a holder differ. It is sectional drawing which shows the other Example from which the magnet for sensors and a holder of the control unit integrated electric drive device by Embodiment 4 of this invention differ. It is sectional drawing which shows the magnet for sensors and the holder of the control unit integrated electric drive device by Embodiment 5 of this invention. It is sectional drawing which shows the Example from which the magnet for sensors of the control unit integrated electric drive device by Embodiment 5 of this invention and a holder differ. It is sectional drawing which shows the other Example from which the magnet for sensors and a holder of the control unit integrated electric drive device by Embodiment 5 of this invention differ.

  A preferred embodiment of a control unit-integrated electric drive device according to the present invention will be described below with reference to the drawings.

Embodiment 1 FIG.
1 is a cross-sectional view showing a control unit-integrated electric drive apparatus according to Embodiment 1 of the present invention. A control unit-integrated electric drive device (hereinafter simply referred to as an electric drive device) 1 is used as a drive device for driving a steering gear of an electric power steering device, and controls the motor unit 2 and the motor unit 2 as well as power. An ECU (Electronic Control Unit) 3 is a control unit to be supplied. The motor unit 2 includes a housing 4 that is fixed to a steering gear (not shown), a cylindrical stator 5 that is an armature that is fixed inside the housing 4, and a magnetic that is rotatably supported by the housing 4. A body shaft 6 and a rotor 7 fixed to the shaft 6 and rotatably opposed to the stator 5 through a gap are provided. The rotor 7 is constituted by a permanent magnet.

  The assist torque output by the electric drive device 1 according to the driver's steering force is transmitted to the shaft of the steering gear via a pulley or boss fitted to one end of the shaft 6. The transmitted torque is converted from a rotational motion to a parallel motion force that changes the direction of the steering wheel, and the vehicle is steered. Further, a sensor magnet 9 facing the semiconductor sensor 8 as a rotation angle detecting means for detecting the rotation angle of the rotor 7 and a holder 10 supporting the sensor magnet 9 are press-fitted into the other end of the shaft 6 and fitted. The rotor 7 is integrally rotatable.

  The ECU unit 3 is disposed coaxially with the motor unit 2 on the side 12 opposite to the fixed side 11 to the steering gear. The semiconductor sensor 8 is constituted by a Hall sensor, a magnetoresistive sensor, or the like that detects a magnetic field of a rotatable sensor magnet 9. The motor unit 2 is controlled by an ECU unit 3 that performs power supply and control signal input / output, for example, an inverter circuit and its control circuit, according to the rotation angle of the rotor 7 detected by the semiconductor sensor 8.

2A and 2B are cross-sectional views showing the sensor magnet 9 and the holder 10 of the electric drive device 1, wherein FIG. 2A is a side cross-sectional view, FIG. 2B is a cross-sectional view taken along the line BB in FIG. These are the sectional views on the AA line of Drawing 2 (a).
The sensor magnet 9 is composed of an injection-molded magnet having a cylindrical portion 20 and flat portions 21 at both ends of the cylindrical portion 20. The sensor magnet 9 is integrally formed with a holder 10 made of a nonmagnetic material such as stainless steel. The holder 10 is drawn into a shape having a hollow cylindrical portion 22 and a flat portion 23 at one end of the cylindrical portion 22. A central hole 24 is formed in the flat portion 23 of the holder 10, and the sensor magnet 9 is integrally formed in the hollow portion 25 of the cylindrical portion 22 of the holder 10 by injection molding through the central hole 24.

  Here, when the thickness of the portion of the sensor magnet 9 that overlaps the holder 10 in the axial direction of the shaft 6 is t2, and the thickness of the portion that does not overlap the holder 10 other than the thickness t2 is t1, t1 > T2.

  As described above, the sensor magnet 9 is integrally formed by injection molding in the hollow portion 25 of the cylindrical portion 22 of the holder 10, so that the sensor magnet 9 can be prevented from being detached from the holder 10. By integrating the sensor magnet 9 and the holder 10, handling in the magnetizing process and the press-fitting process into the shaft 6 becomes easy.

  Further, when the flat portion 23 of the holder 10 is pressed into the shaft 6, it can receive the press-fit stress without applying excessive press-fit stress to the sensor magnet 9. Does not occur.

  Moreover, the fitting part 26 of the holder 10 and the shaft 6 is circular with respect to each other, and does not have a relative positioning shape. At one end of the shaft 6, a center hole 27 for supporting the rotor 7 by assembling the motor unit 2 is provided, and the sensor magnet 9 is disposed away from the end surface of the shaft 6. For this reason, the residual stress of press-fitting between the holder 10 and the shaft 6 does not act on the sensor magnet 9, and the sensor magnet 9 is not chipped or cracked.

The electric drive device 1 according to the first embodiment is configured as described above, and the following effects are obtained.
First, when the holder 10 is press-fitted into the shaft 6 after magnetizing the sensor magnet 9, there is no restriction on the relative angle of the rotor 7 and the magnetizing direction, and if the rotor angle is fixed, the circular shaft 6 can be fitted. The fitting part 26 can be press-fit as it is, and there is a feature that equipment such as detecting the angle of the fitting part 26 with a sensor or a camera becomes unnecessary. Further, since the holder 10 is formed by drawing, this can be realized with a simple structure.

  In addition, the sensor magnet 9 can be magnetized by the magnetizing yoke through only the air gap regardless of the shape of the holder 10, so that the required current value is small and the temperature rise of the magnetizing yoke can be reduced. Since there is no hole in the sensor magnet 9, there is a small deviation in the orientation of magnetization and a uniform parallel orientation can be obtained.

  Further, since the sensor magnet 9 has a cylindrical shape and the shaft 6 and the sensor magnet 9 are not in contact with each other, the leakage magnetic flux is small. Since it can arrange | position close to the magnet 9 for sensors, the remarkable effect that the miniaturization and weight reduction of the electric drive device 1 which integrated the motor part 2 and ECU part 3 is attained is acquired.

  Usually, since the center hole which supports the rotor 7 by the assembly of the motor part 2 is provided in the end surface of the shaft 6, the perpendicularity of the end surface of the shaft 6 and the shaft 6 is not favorable. When the sensor magnet 9 is brought into contact with the end surface of the shaft 6, the end surface of the shaft 6 serves as a reference, so that the sensor magnet 9 is tilted with respect to the shaft 6 or the holder 10 is buckled to be eccentric with respect to the shaft 6. As a result, the rotating magnetic field is distorted, the angle detection accuracy is deteriorated, and the torque ripple is deteriorated. However, according to the first embodiment, since the shaft 6 and the sensor magnet 9 are not brought into contact with each other, this problem can be solved and the steering feeling can be improved.

Embodiment 2. FIG.
Next, an electric drive device according to Embodiment 2 of the present invention will be described. Since the electric drive device according to the second embodiment is the same as that of the first embodiment except for the sensor magnet and the holder, the illustration is omitted, and here, the sensor magnet and the holder having different configurations will be described.

FIG. 3 is a cross-sectional view showing a sensor magnet and a holder of the electric drive device according to the second embodiment, and the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals. 3A is a side sectional view, FIG. 3B is a sectional view taken along line BB in FIG. 3A, and FIG. 3C is a sectional view taken along line AA in FIG.
In FIG. 3, the gap distance between the end surface of the shaft 6 and the sensor magnet 9 is defined as g. At this time, when the gap distance g is changed by 1 mm, the increase rate of the magnetic field intensity detected by the semiconductor sensor 8 (see FIG. 1) is shown in FIG. For example, when the gap distance g is increased from 0.5 mm to 3.5 mm, the magnetic field strength increases by the area surrounded by the horizontal axis and the vertical axis, that is, the integrated value.

  This is because the diameter of the sensor magnet 9 is 15 mm, the thickness is 5 mm, the outer diameter of the shaft 6 is 10 mm, the holder 10 is a non-magnetic material having a thickness of 0.5 mm, and the semiconductor sensor 8 is positioned 2 mm above the central axis of the sensor magnet 9. This is the calculation result when The vertical axis indicates the magnetic field strength when the sensor magnet 9 is in contact with the end face of the shaft 6 as 100%, and the magnetic flux intensity to the shaft 6 of the magnetic material can be reduced with respect to the gap distance g. The rate of increase is always a positive value. When the gap distance g is 2 mm or less, the increase rate of the magnetic field strength is large. However, when the gap distance is 2 mm or more, the increase rate is small because the leakage magnetic flux to the shaft 6 increases and decreases the magnetic resistance of the gap. It turns out that it becomes.

  The angle detection accuracy in the semiconductor sensor 8 also depends on the relative distance between the semiconductor sensor 8 and the sensor magnet 9. When the relative distance fluctuates for each individual electric drive unit that integrates the motor and control unit, there is a large variation in angle detection error due to variations in magnetic field strength, and a large variation in torque ripple superimposed on the output torque. There's a problem.

  For example, when the holder 10 is press-fitted with the fixed side 11 (refer to FIG. 1) to the steering gear as a reference, the axial tolerance of the sensor magnet 9 is determined by the shaft tolerance, and the semiconductor sensor 8 includes the housing 4 and the ECU unit 3. The relative distance variation is large. In such a case, the variation in magnetic field strength can be reduced by setting the gap distance g to 2 mm or more. Further, since the magnetic field strength is large, there is an advantage that the thickness of the sensor magnet 9 can be reduced to reduce the cost by reducing the leakage magnetic flux.

  On the other hand, when the electric power steering device is installed in a light vehicle or a small vehicle, the allowable value of torque ripple may be smaller and the influence on steering feeling may be smaller than that of a medium-sized vehicle or larger vehicle with a large output torque. is there. In this case, by setting the gap distance g to 2 mm or less, the total length of the electric drive device in which the motor and the control unit are integrated can be reduced. Therefore, in a small automobile or less arranged in a direction perpendicular to the steering column of the electric steering device, there is less interference with other in-vehicle devices and the driver's legs, so that the advantage of improved mountability can be obtained. Needless to say, in a small vehicle having a small vehicle weight, the effect of improving the fuel consumption can be achieved by reducing the weight of the electric drive unit in which the motor and the control unit are integrated.

  As described above, the electric drive device according to the second embodiment has a remarkable effect that the torque ripple improvement or the reduction in size and weight can be selectively realized from the first embodiment.

Embodiment 3 FIG.
Next, an electric drive device according to Embodiment 3 of the present invention will be described. The electric drive device according to the third embodiment is the same as that of the first or second embodiment except for the sensor magnet and the holder. Therefore, the illustration is omitted. Here, the sensor magnet and the holder having different configurations are described here. Will be described.
FIG. 5 is a sectional view showing a sensor magnet and a holder of the electric drive device according to the third embodiment, and the same or corresponding parts as those in the first or second embodiment are denoted by the same reference numerals. 5A is a side sectional view, FIG. 5B is a sectional view taken along line BB in FIG. 5A, and FIG. 5C is a sectional view taken along line AA in FIG.

  As shown in FIG. 5, the holder 10 of the electric drive device according to Embodiment 3 has a center hole 24 formed in a polygonal shape. For this reason, it functions as a detent of the sensor magnet 9 with respect to the holder 10.

The shape for functioning as a rotation stopper is not limited to a polygonal shape, and the same function can be achieved with the following shapes.
That is, FIG. 6 shows a case where the center hole 24 is provided at an eccentric position with respect to the rotation center axis, and FIG. 7 shows a case where a plurality of center holes 24 are provided. FIG. 8 shows a case where a recess 30 is provided in the flat portion 23 of the holder 10 in addition to the center hole 24.

  Also in the electric drive device according to the third embodiment configured as described above, the same effects as those of the first or second embodiment can be obtained.

Embodiment 4 FIG.
Next, an electric drive device according to Embodiment 4 of the present invention will be described. The electric drive device according to the fourth embodiment is the same as the first embodiment, the second embodiment, or the third embodiment except for the sensor magnet and the holder. Different sensor magnets and holders will be described.
FIG. 9 is a cross-sectional view showing a sensor magnet and a holder of the electric drive device according to the fourth embodiment, and the same reference numerals are used for the same or corresponding parts as those of the first, second, or third embodiment. Is attached. 9A is a side sectional view, FIG. 9B is a sectional view taken along line BB in FIG. 9A, and FIG. 9C is a sectional view taken along line AA in FIG.

As shown in FIG. 9, in the holder 10 of the electric drive device according to the fourth embodiment, the plane portion 23 is disposed outside the cylindrical portion 22.
Thus, also in the electric drive device according to the fourth embodiment in which the flat portion 23 of the holder 10 is arranged outside the cylindrical portion 22, the same effect as that of the first, second, or third embodiment. It is clear that This is particularly effective when the outer diameter of the shaft 6 is smaller than the outer diameter of the sensor magnet 9. Similarly, as shown in FIG. 10 and FIG. 11, the same effect can be obtained even if the extension portion 31 further extending in the axial direction is provided on the plane portion 23.

Embodiment 5. FIG.
Next, an electric drive device according to Embodiment 5 of the present invention will be described. The electric drive device according to the fifth embodiment is the same as the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment except for the sensor magnet and the holder. Here, sensor magnets and holders having different configurations will be described.
FIG. 12 is a cross-sectional view showing the sensor magnet and holder of the electric drive device according to the fifth embodiment, which is the same as or corresponds to the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment. The parts are given the same reference numerals. 12A is a side sectional view, FIG. 12B is a sectional view taken along line BB in FIG. 12A, and FIG. 12C is a sectional view taken along line AA in FIG.

As shown in FIG. 12, the holder 10 of the electric drive device according to the fifth embodiment has a notch 32 in the flat portion 23.
Thus, also in the electric drive device by Embodiment 5 which has the notch part 32 in the plane part 23 of the holder 10, it is the same as that of Embodiment 1, Embodiment 2, Embodiment 3, or Embodiment 4. Furthermore, it functions as a detent for the sensor magnet 9 with respect to the holder 10.

  The shape for functioning as a rotation stopper is not limited to a polygonal shape, and a similar function can be achieved with the following shapes. That is, as shown in FIG. 13 and FIG. 14, this is a case where the recess 33 is provided in the flat portion 23.

  Also in the electric drive device according to the fifth embodiment configured as described above, the same effects as those of the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment can be obtained.

  As described above, the first to fifth embodiments have been described. However, within the scope of the present invention, the embodiments can be freely combined, or the embodiments can be appropriately modified or omitted. Is possible.

DESCRIPTION OF SYMBOLS 1 Electric drive device, 2 Motor part, 3 ECU part, 4 Housing, 5 Stator, 6 Shaft, 7 Rotor, 8 Semiconductor sensor, 9 Magnet for sensors, 10 Holder, 11 Fixed side, 12 Opposite side, 20 Cylindrical part , 21, 23 Planar part, 22 Cylindrical part, 24, 27 Center hole, 25 Hollow part, 26 Fitting part, 30, 33 Recess, 31 Extension part, 32 Notch part

The present invention by the control unit integrated electric drive, a control unit for controlling the motor unit is disposed coaxially with the output shaft of the motor unit, said control unit and integrated the motor unit control unit integrated electric drive In
The motor unit includes a stator fitted to an inner periphery of a housing, a shaft rotatably supported by the housing, a rotor fixed to the shaft and facing the stator via a gap, A sensor magnet fixed to one end of the shaft opposite to the motor output side and integrated with a holder, a rotation angle detection means for detecting a magnetic field of the sensor magnet, and the rotation angle detection means detected by the rotation angle detection means A control unit that controls the motor unit according to the rotation angle of the rotor,
The holder is formed of a cylindrical nonmagnetic material having a bottom surface with a hole at one end, and the sensor magnet has a thickness of a portion overlapping the holder in the axial direction of the shaft as t2. , if the thickness of the portion does not overlap with the holder other than the thickness t2 was t1, mono conjugated to either side and the outer peripheral side of the bottom surface of the holder has a t1> t2 the relationship,
The holder and the sensor magnet are arranged so as to be separated from one end of the shaft via a gap, and a fixed portion of the holder with the shaft has a circular contact surface.

On the other hand, if in the case where the electric power steering apparatus is mounted on a light car and small vehicles, as compared to a large duty vehicles or vehicle output torque, small allowable value of the torque ripple, a small effect on the steering feeling There is. In this case, by setting the gap distance g to 2 mm or less, the total length of the electric drive device in which the motor and the control unit are integrated can be reduced. Therefore, in a small automobile or less arranged in a direction perpendicular to the steering column of the electric steering device, there is less interference with other in-vehicle devices and the driver's legs, so that the advantage of improved mountability can be obtained. Needless to say, in a small vehicle having a small vehicle weight, the effect of improving the fuel consumption can be achieved by reducing the weight of the electric drive unit in which the motor and the control unit are integrated.

Claims (6)

In the control unit integrated electric drive device in which the control unit for controlling the motor unit is arranged coaxially with the output shaft of the motor unit, and the control unit and the motor unit are integrated,
The motor unit includes a stator fitted to an inner periphery of a housing, a shaft rotatably supported by the housing, a rotor fixed to the shaft and facing the stator via a gap, A sensor magnet fixed to one end of the shaft opposite to the motor output side and integrated with a holder, a rotation angle detection means for detecting a magnetic field of the sensor magnet, and the rotation angle detection means detected by the rotation angle detection means A control unit that controls the motor unit according to the rotation angle of the rotor,
The holder is composed of a cylindrical non-magnetic material having a bottom surface with a hole at one end, and the sensor magnet is injection-molded and integrated on both sides and the outer peripheral side of the holder,
The holder and the sensor magnet are arranged so as to be spaced apart from one end of the shaft via a gap, and the fixed portion of the holder to the shaft has a circular contact surface. Unit-integrated electric drive.   When the thickness of the portion of the sensor magnet that overlaps the holder in the axial direction of the shaft is t2, and the thickness of the portion that does not overlap the holder other than the thickness t2 is t1, t1> t2 The control unit-integrated electric drive device according to claim 1, wherein:   The control unit-integrated electric drive device according to claim 1, wherein the holder includes a rotation stopper for the sensor magnet.   The control unit-integrated electric drive device according to any one of claims 1 to 3, wherein the holder is drawn.   5. The control unit according to claim 1, wherein the sensor magnet has a gap of 2 mm or more between the shaft end surface and is held by the holder. Body type electric drive device. 5. The control unit according to claim 1, wherein the sensor magnet has a gap of less than 2 mm between the shaft end face and is held by the holder. Body type electric drive device.

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