JP2020022243A - Rotor of rotary electric machine, and rotary electric machine for power steering of automobile including the same - Google Patents

Abstract

To improve reliability by facilitating assembling and suppressing contamination.SOLUTION: The rotor of a rotary electric machine includes: a magnet; a rotor core forming a storage space for storing the magnet; a rotary shaft connected to the rotor core; and a cover for covering an opening of the rotor core connected to the storage space. The cover is made of a magnetic material and is attracted toward the opening of the rotor core by a magnetic force of the magnet.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a rotor for a rotating electric machine, and more particularly to a rotating electric machine for an auxiliary machine for an automobile and a rotating electric machine for a power steering.

  As a background art of this technical field, Japanese Patent Application Laid-Open No. 2012-217285 discloses a side cover used for a rotor of a rotating electric machine.

  This patent publication discloses end plates arranged on both axial end surfaces of the rotor, and the end plate has an arc-shaped bent portion called an intermediate bent portion between the tip side piece and the root bent portion. It is arranged convexly outward in the direction. When the end plate is pressed against and fixed to the shaft end face of the rotor, the intermediate bent portion absorbs the force received from the tip side piece and is fixed to the rotor end face in close contact.

  In order to deform the intermediate bent portion at the time of pressing the end plate and bring the end plate into complete contact with the rotor core, there is a problem that the pressing force becomes large, and it is necessary to increase the size of the press-fitting equipment. Further, since the open end of the end plate is extended toward the outer diameter side while the end plate rubs against the surface of the rotor core, there is a possibility that contamination occurs when the end plate is attached.

JP 2012-217285 A

  An object of the present invention is to improve reliability by facilitating assembly and suppressing contamination.

  The rotor of the rotating electric machine according to the present invention includes a magnet, a rotor core forming a storage space for storing the magnet, a rotating shaft connected to the rotor core, and a cover covering an opening of the rotor core connected to the storage space. The cover is made of a magnetic material, and is attracted toward the opening of the rotor core by the magnetic force of the magnet.

  According to the present invention, the cover is made of a magnetized material, can be easily bent at the time of assembling, and the cover is held by the rotor core with the attractive force of the magnet embedded in the rotor core to further narrow the gap, thereby facilitating assembly and contamination. And the reliability can be improved.

1 is an external view of an electric power steering system according to an embodiment. FIG. 2 is an external perspective view of a motor 100 incorporated in the steering device 200 according to the embodiment. FIG. 3 is a sectional view of the motor 100 shown in FIG. 2. FIG. 4 is an overall perspective view of a rotor 16 of the motor 100 described in FIG. 3. FIG. 4 is a perspective view illustrating a method of assembling the rotor 16. FIG. 7 is a cross-sectional view showing a state in which an F side cover 30F and an R side cover 30R are press-fitted into a rotor core 8; It is sectional drawing which shows the structure of F side cover 30F or R side cover 30R which concerns on 1st Embodiment. It is sectional drawing which shows the structure of the side cover concerning 2nd Embodiment. It is a sectional view showing the structure of the side cover concerning a 3rd embodiment.

  An embodiment according to the present invention will be described below with reference to FIGS.

  FIG. 1 is an external view of an electric power steering system according to the present embodiment.

  The electric power steering system has a steering device 200 using the motor 100. A pinion (not shown) is provided at a lower end of the steering shaft 202 connected to a steering wheel (not shown). This pinion meshes with a rack (not shown) that is long in the left-right direction of the vehicle body.

  Tie rods 203 for steering the front wheels in the left-right direction are connected to both ends of the rack, and the rack is covered by a rack housing 204. A rubber boot 205 is provided between the rack housing 204 and the tie rod 203.

  An electric power steering device 206 is provided to assist the torque when the steering wheel is turned. A torque sensor 207 for detecting a turning direction and a turning torque of the steering shaft 202; a motor 100 for applying a steering assist force to the rack via a gear 210 based on a detection value of the torque sensor 207; And a control ECU (ELECTRIC CONTROL UNIT) 209 for controlling the control.

  In such a structure, the control ECU 209 detects the start of steering from the rate of change of the steering angle detected by the torque sensor 207, and can control the motor output as a steering assist force at the start of steering. I have.

  As described above, the motor 100 generates the assisting force of the steering force, and makes it easier for the driver to cut the dull angle. In addition, since the motor 100 and the steering wheel (not shown) are mechanically connected, locking inside the motor 100 causes a trouble in the steering operation. Therefore, there must be no intrusion of contaminants into the motor from the outside or occurrence of contaminants in the motor.

  FIG. 2 is an external perspective view of the motor 100 incorporated in the steering device 200 according to the present embodiment.

  The motor 100 has a housing 1 in which a stator core is housed, and a bracket 2 attached to the steering device 200. The control ECU 209 (not shown) is connected to a shaft of the housing 1 opposite to the bracket 2. From the motor 100, a coil lead wire 50 of three-phase winding is taken out to the control ECU 209. The output of the motor 100 is transmitted to a rack gear 210 via a gear (not shown) provided on the shaft 3.

  FIG. 3 is a sectional view of the motor 100 shown in FIG.

  An O-ring 6 is provided between the housing 1 and the bracket 2. Further, an F bearing 5 for supporting the shaft 3 is fixed to the bracket 2 with a bevel type screw 4.

  The housing 1 is provided with an R bearing 10 as another bearing, and the shaft 3 has a structure rotatable by these bearings.

  The rotor 16 has a shaft 3 and a rotor core 8. The magnet 7 is provided in the rotor core 8 to have an embedded structure.

  A stator core 9 is provided inside the housing 1, and two windings are arranged in a slot portion of the stator core 9. This winding is composed of two electrically independent three-phase windings, and a first winding 20 disposed on the inner peripheral side of the slot and an outer peripheral side of the first winding 20. And the second system winding 21 to be arranged.

  Between these two windings, an insulating member 11 is arranged on the output shaft side and an insulating member 11R is arranged on the non-output side for the purpose of preventing a short circuit between the systems. The outputs of these two-system windings project from the motor 100 to the control circuit side as coil lead wires 50.

  As the coil lead wires 50, a total of twelve UVW input wires for two-system winding and neutral wires for two-system UVW are output.

  FIG. 4 is an overall perspective view of the rotor 16 of the motor 100 described in FIG.

  The rotor 16 has the rotor core 8 press-fitted into the shaft 3. Further, the rotor core 8 is provided with a space for inserting the magnet 7 on the inner peripheral side, and the magnet 7 is arranged. The F side cover 30F and the R side cover 30R are press-fitted into the shaft 3 similarly to the rotor core 8 at both ends. Have been.

  FIG. 5 is a perspective view showing a method of assembling the rotor 16.

  First, as shown on the leftmost side of FIG. 5, the shaft 3 is press-fitted into the rotor core 8 from the illustrated direction. At this time, the press surface of the rotor core 8 is press-fitted from the sagging side, thereby suppressing the generation of contamination and stabilizing the press-fitting. The shaft 3 of this embodiment is provided with two devices for reducing the press-fit such as knurling at the press-fit portion of the rotor core 8.

  As shown second from the left side in FIG. 5, after the press-fitting of the rotor core 8, the R side cover 30 </ b> R corresponding to the illustrated lower surface is press-fitted into the end face of the rotor core 8.

  As shown third from the left side in FIG. 5, the magnet 7 is inserted into the rotor core 8.

  As shown in the fourth from the left in FIG. 5, after the F side cover 30F is press-fitted into the shaft 3, the rotor ASSY is completed.

  Although the magnetizing step, which is the next step, is not shown, the rotor ASSY has no reference position such as a lightening hole in the rotor core 8 corresponding to the magnet 7, so that the magnetizing yoke and the magnet are positioned with respect to the magnetizing. A mechanical positioning step is required.

  Therefore, in this step, a preliminary current is applied to the coil wound around the magnetized yoke of the rotor, and the rotor 8 is rotated to an appropriate position. At this time, the contact rotation surface between the tip of the shaft 3 and the magnetized yoke is supported so that the shaft 3 can be easily rotated. For example, the shaft 3 is rotatably supported from above and below with reference to a center hole provided above and below the shaft 3. Before the end of the pre-excitation, the shaft supporting the center hole of the shaft 3 is strongly pressed against the hole of the shaft 3 to suppress the rotation of the rotor 16 and remove the excitation. In the next step, a magnetizing current is passed through the coil of the magnetizing yoke to magnetize the magnet arranged inside the rotor.

  FIG. 6 is a cross-sectional view showing a state in which the F side cover 30F and the R side cover 30R are press-fitted into the rotor core 8.

  Both end faces of the magnet 7 provided inside the rotor core 8 have a structure that can prevent the F side cover 30F and the R side cover 30R from jumping out, partially cracking, chipping, and the like.

  FIG. 7 is a sectional view showing the structure of the F side cover 30F or the R side cover 30R according to the first embodiment. The left side of FIG. 7 shows the shape of the side cover before press-fitting the shaft 3, and the right side of FIG. 7 shows the shape of the side cover after press-fitting the shaft 3. In the side cover according to the first embodiment, the F side cover 30F and the R side cover 30R have the same structure.

  The side cover includes a cylindrical shaft press-fit portion 32 that is press-fitted into the shaft 3 and a disk-shaped portion that extends in the radial direction.

  The contact portion 31 </ b> B corresponds to a portion that has been bent in the outer diameter direction from the shaft press-fitting portion 32 and contacts the rotor core 8. The contact portion 31 </ b> A is provided at the outermost diameter portion and contacts the rotor core 8.

  Before the side cover is pressed into the shaft 3, the contact portions 31A and 31B are in a state where a step is formed as shown in the left diagram of FIG.

  When the side cover is press-fitted into the shaft 3, the portion that first comes into contact with the rotor core 8 is the contact portion 31A. When further press-fitting, the contact portion 31B of the side cover comes into contact with the end face of the rotor core 8. At this time, the disk portion of the side cover is curved, and the contact portion 31A receives a strong force in the direction in which the rotor core 8 is crushed from the axial direction, and acts to reduce the gap between the rotor core 8 and the side cover.

  The material of the side cover is made of a magnetic material, forms a magnetic circuit of magnet magnetic flux provided inside the rotor core 8, and has an effect of reducing a gap between the rotor core 8 and the side cover by magnetic attraction.

  Further, even when the magnet 7 is cracked or chipped, the magnet piece is made of a magnetic material, so that even if a gap is generated between the rotor core 8 and the side cover, the magnet pieces are attracted to each other by an attractive force between the rotor core 8 and the side cover. 16 can be prevented from coming out.

  FIG. 8 is a cross-sectional view illustrating the structure of the side cover according to the second embodiment.

  The difference between the first embodiment and the second embodiment is that a bent portion 33 is provided between the contact portion 31A and the contact portion 31B at the outermost periphery of the side cover 30. Due to the bent portion 33, when the side cover 30 is pressed against the rotor core 8, the reaction force is large and the cost of the press-fitting equipment is increased with the same plate thickness. This is for facilitating deformation so that the portion 31A can easily contact the rotor core 8 with a small pressure input. As a specific method of manufacturing the curved portion 33, the curved portion 33 is formed by molding with a die when forming by a press. Since the method of assembling the side cover is the same as that described above, detailed description is omitted.

  FIG. 9 is a cross-sectional view illustrating the structure of the side cover according to the third embodiment.

  The third embodiment is different from the above-described second embodiment in that the outer peripheral side of the curved portion 33 is made thinner by partially providing the curved portion 33. This portion is shown as a thin plate portion 35. This effect improves the assemblability by allowing the side cover to be deformed with a small force at the time of press-fitting the side cover similarly to the curved portion 33 described above.

  Further, the material of the side cover is made of a material having magnetism, which is common to all the embodiments. Specifically, it is made of a material typified by an iron plate or a material that is magnetized by mechanical stress such as SUS304 of stainless steel. As a result, the portion in contact with the rotor core 8 is magnetized by the press strain, and the magnetic circuit of the magnet 7 provided in the rotor core 8 forms a closed circuit through the side cover. Thus, even if the tip of the side cover is thinned, the motor can be gently rotated without the side cover fluttering due to centrifugal force while the rotor is rotating.

  Further, regarding the plate thickness suitable for the side cover, when the thickness is large, the press-in force becomes large, the equipment cost becomes effective, and the leakage magnetic flux for adsorbing the side cover becomes large, so that the characteristics are lowered. Further, when the side cover is thin, the leakage flux adsorbing the side cover is reduced, but the fixing force of the side cover is reduced, so that the ideal thickness is preferably about 0.5 mm.

DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... Bracket, 3 ... Shaft, 4 ... Bevel type tomewa, 5 ... F bearing, 6 ... O-ring, 7 ... Magnet, 8 ... Rotor core, 9 ... Stator core, 10 ... R bearing, 11 ... Insulating member, 11R: insulating member, 16: rotor, 20: first system winding, 21: second system winding, 30F: F side cover, 30R: R side cover, 31A: contact portion, 31B: contact portion, 32: shaft Press-fitting part, 33 ... bending part, 34 ... parallel part, 35 ... thin plate part, 50 ... coil lead wire, 100 ... motor, 200 ... steering device, 202 ... steering shaft, 203 ... tie rod, 204 ... rack housing, 205 ... rubber boots , 206: electric power steering device, 207: torque sensor, 209: control ECU, 210: gear

Claims (8)

A magnet,
A rotor core forming a storage space for storing the magnet,
A rotating shaft connected to the rotor core,
A cover that covers an opening of the rotor core connected to the storage space,
The rotor of the rotating electric machine, wherein the cover is made of a magnetic material, and is attracted toward the opening of the rotor core by a magnetic force of the magnet. It is a rotor of the rotary electric machine according to claim 1, wherein
The cover,
A first contact portion on the side close to the rotation axis and in contact with the rotor core;
A second contact portion on the side close to the opening and in contact with the periphery forming the opening;
An intermediate portion that forms a space between the first contact portion and the second contact portion and between the rotor core and generates a pressing force toward the opening portion with respect to the second contact portion; Of a rotating electric machine having the same. It is a rotor of the rotary electric machine according to claim 2,
The rotor of the rotating electric machine, wherein the intermediate portion has a curved shape formed so as to provide a gap with the rotor core. It is a rotor of the rotating electrical machine according to claim 2 or 3,
The rotor of a rotating electrical machine, wherein the cover has a bent portion formed between the second contact portion and the intermediate portion, the bent portion being smaller than the thickness of the second contact portion and the intermediate portion. It is a rotor of the rotating electrical machine according to claim 2 or 3,
The thickness of the second contact portion is smaller than the thickness of the first contact portion. It is a rotor of the rotary electric machine according to any one of claims 1 to 5, wherein
The cover is made of stainless steel, and the rotor of the rotating electric machine is made of a material that is magnetized by press molding. It is a rotor of the rotary electric machine according to any one of claims 1 to 6, wherein
The rotor of the rotating electric machine, wherein a thickness of the cover is approximately 0.5 mm.   A rotating electric machine for power steering of an automobile, comprising: the rotor according to any one of claims 1 to 6; and a stator.

Images