WO2007111031A1

WO2007111031A1 - Motor and drive control device

Info

Publication number: WO2007111031A1
Application number: PCT/JP2007/050707
Authority: WO
Inventors: Hiroshi Koyama; Hirohumi Doi; Kenta Hatano; Tomokuni Katou
Original assignee: Mitsubishi Electric Corporation
Priority date: 2006-03-24
Filing date: 2007-01-18
Publication date: 2007-10-04
Also published as: DE112007000576T5; JP5306808B2; CN101405929B; CN101405929A; JPWO2007111031A1

Abstract

A motor comprises a rotor (3) having a permanent magnet (2) outer periphery of which is magnetized into multiple poles and a stator (7) having a plurality of energizing coils (7a) disposed along the outer periphery of the rotor (3). The rotor (3) is rotated by a radially inhomogeneous magnetic field produced when a current flows through the energizing coils (7a). The motor further comprises a bearing (5) on the load side to which one end of the rotor (3) is axially fixed, a bearing (4) on the anti-load side to which the other end of the rotor (3) is radially fixed, and a damping member (12) radially installed on the bearing (4) on the anti-load side.

Description

Specification

Motor and drive control device

Technical field

[0001] The present invention relates to a motor and a drive control device thereof.

Background art

[0002] For example, Patent Document 1 discloses a conventional noise countermeasure technique for driving a motor. Patent Document 1 reduces noise generated when a member attached to a rotor shaft collides with a bearing when the rotor of a DC (direct current) motor moves in the axial direction during driving.

[0003] In the motor disclosed in Patent Document 1, a boss portion is provided at the center of a hollow cylindrical cushion portion, and a rotor shaft is projected through a center hole of the boss portion. With this cushion portion, even if the bearing of the motor casing collides with the boss portion as the rotor moves in the axial direction, the impact is alleviated.

Patent Document 2 discloses a DC brushless motor that generates a rotating magnetic field by sequentially switching a rotor having a plurality of permanent magnets and a stator winding that is energized based on a position detection signal obtained by the rotation. About. In Patent Document 2, it is possible to reduce the vibration and noise generated by the operation by the energization by controlling the energization at a frequency that avoids the resonance of the rotor.

Patent Document 1: Japanese Patent Laid-Open No. 2000-32706

Patent Document 2: Japanese Patent Laid-Open No. 11 113281

[0006] In a conventional DC motor, the number of magnetic poles does not match between the rotor side and the stator side. For example, the rotor side has eight magnetic poles and the stator side has nine current-carrying coils ( In the rotor 8 pole stator 9 pole), the magnetic force generated when the energizing coil is energized generates uneven force to attract the rotor in the radial direction. For this reason, the rotor swings in the radial direction. On the other hand, a motor with a rotor 8-pole stator 9-pole structure can achieve high output, is easy to manufacture and is relatively easy to use.

[0007] Further, in the structure in which both ends of the rotor are held by bearings, the dimensional variation of the parts is reduced. For this purpose, a radial gap is provided between the bearing and the stator or rotor side. If there is a gap, even if a load is applied to a high-power DC motor such as a vehicle motor, the contact between the bearing and the stator or rotor side is relaxed, and the load applied to the bearing can be reduced. it can. For this reason, in order to improve wear resistance and increase the life, a structure in which the gap is provided is necessary.

[0008] In a motor configured with a combination of rotor 8 poles-stator 9 poles, etc. while applying a force, a configuration in which a radial clearance is provided between the bearing and the stator side or the rotor side is adopted. And, it was amazing that abnormal noise was generated during driving. As a result of research and analysis of this factor by the inventor of the present invention, the rotor swings in the radial direction by the amount of the gap due to the unequal radial force generated when energized, and the bearing and the stator side or the rotor side are The contact was found to be the cause.

[0009] With respect to such a problem caused by the radial deflection of the rotor, the effect of applying the technology for abnormal noise generated by the axial movement of the rotor disclosed in Patent Document 1 is also effective. Can't get. In addition, since the above problems occur due to structural factors of the motor, countermeasures by energization control as in Patent Document 2 are not effective!

[0010] The present invention has been made to solve the above-described problems, and in a motor that rotates a rotor by a magnetic field that is not uniform in the radial direction, a buffer member is provided on the side of the bearing. Thus, an object of the present invention is to obtain a motor that can absorb the collision with the bearing due to the radial deflection of the rotor, reduce the generation of abnormal noise, and reduce the impact on the bearing.

[0011] Further, the present invention drives a motor whose rotor swings in the radial direction when driven.

A drive control device that can reduce the contact with the bearing and suppress the generation of noise by controlling the drive at a drive frequency high enough to mitigate the collision of the rotor drawn in the radial direction with the bearing. The purpose is to obtain.

Disclosure of the invention

[0012] A motor according to the present invention includes a rotor having a magnet whose outer periphery is magnetized in plural, and a stator having a plurality of energizing coils arranged along the outer periphery of the rotor. For motors in which the rotor rotates with an uneven magnetic field generated in the radial direction A load-side bearing that fixes one end of the rotor in the axial direction, an anti-load-side bearing that fixes the other end of the rotor in the radial direction, and a damping member provided in the radial direction of the anti-load-side bearing; It is equipped with.

[0013] According to this invention, since the shock of the collision due to the radial deflection of the rotor is absorbed by the buffer member, the occurrence of abnormal noise is reduced and the shock applied to the bearing can be reduced. There is an effect that can be done. As a result, the wear resistance can be improved and the life can be increased.

There are effects such as.

Brief Description of Drawings

FIG. 1 is a cross-sectional view showing the structure of a motor according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view showing the eccentricity of the rotor during driving.

FIG. 3 is an enlarged view of a portion indicated by symbol B in FIG.

FIG. 4 is an enlarged view of a portion indicated by symbol C in FIG.

FIG. 5 is a view showing an example of a buffer member.

FIG. 6 is a view showing another example of the buffer member.

FIG. 7 is a block diagram showing a configuration of a motor drive system according to a second embodiment of the present invention.

FIG. 8 is a diagram for explaining the movement of the rotor during driving.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to describe the present invention in more detail, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1.

FIG. 1 is a cross-sectional view showing the structure of a motor according to Embodiment 1 of the present invention, showing a cross section in the axial direction, and showing a rotor 8-pole-stator 9-pole motor. The motor 1 is roughly configured to include a rotor 3 and a stator 7. The rotor 3 is provided with a permanent magnet 2 magnetized in a plurality of poles along the outer periphery, and a screw hole is provided in the central shaft portion thereof. Here, the permanent magnet 2 is NS magnetized to 8 poles.

[0016] The screw hole provided in the rotor 3 described above is arranged on the opposite side of the output end of the output shaft 11. The installed screw 10 is inserted and inserted. When the rotor 3 is rotationally driven, the rotational force is transmitted to the output shaft 11 through the screw 10 and the output shaft 11 is prevented from rotating, so the rotational force of the rotor 3 is converted to the axial direct power. Converted.

[0017] A stator 7 is a stator (iron core) 7a disposed so as to surround the rotor 3 in a motor cover (motor housing) 9a, and an energization coil is wound around the stator 7. Here, nine stators 7a are disposed so as to surround the rotor 3, and energizing coils are wound around these stators 7a, and NS magnetized to 9 poles by energization.

FIG. 2 is a view for explaining the eccentricity of the rotor 3 at the time of driving, and shows a cross section taken along the line AA in FIG. In addition, in order to visually recognize the relationship between the stator and the rotor, the description of the energizing coil in the stator is omitted. Figures 2 (a) and 2 (c) differ from the motor 1 according to the first embodiment in that the rotor 3 has 12 poles and the stator 7 has 9 current coils. Fig. 2 (b) and Fig. 2 (d) show the motor 1 according to the first embodiment, which shows a rotor 8 pole stator 9 pole motor. .

[0019] Fig. 2 (a) and Fig. 2 (b) show the situation when the U phase is energized from the V phase. Fig. 2 (c) and Fig. 2 (d) show the situation from the U phase to the W phase. The situation when the phase is energized is shown. As shown in Fig. 2, when the energizing coil of the stator is energized, the stator (iron core) is magnetized, and a force that attracts the permanent magnet pole of the rotor is generated. At this time, as shown in Fig. 2 (a) and Fig. 2 (c), in the rotor 12-pole stator 9-pole motor, the magnetic field is uniformly generated by energizing the energizing coil. The attracting force acts equally in each direction (indicated by the arrows in Fig. 2 (a) and Fig. 2 (c)), and the rotor is not eccentric.

[0020] On the other hand, if the rotor has 8 poles and the stator has 9 poles as in the motor 1 of the first embodiment, non-uniform magnetic fields are generated in the radial direction by energizing the energizing coil, and the rotor 3 The force that attracts the rotor 7 toward the radial stator 7 is applied unevenly (the force indicated by the arrow in Figs. 2 (b) and 2 (d)). The bearing holder 3a swings and contacts the inner ring 4a of the upper bearing 4 to generate noise.

Therefore, in the first embodiment, as shown in FIG. 1, the buffer member 12 is provided in the gap between the bearing holding portion 3a of the rotor 3 and the inner ring 4a of the upper bearing 4 to generate noise. Suppress. The buffer member 12 will be described later.

Returning to the description of FIG. 1, a boss (motor casing) 9b is assembled to the motor cover 9a, and the boss 9b holds a preload member 8 such as a washer. Further, an upper bearing 4 and a lower bearing 5 are attached to both ends of the rotor 3 to hold the rotating shaft.

[0023] Here, the holding structure of the lower bearing 5 will be described in detail.

FIG. 3 is an enlarged view of a portion indicated by a symbol B in FIG. As shown in FIG. 3, the inner ring 5a of the lower bearing 5 is fixed up and down in the axial direction by the step 3b of the rotor 3 and the holding mechanism 6 (fixed in the axial direction). Further, the outer ring 5b of the lower bearing 5 is fixed up and down in the axial direction by the step 9c of the motor cover 9a and the preload member 8 held by the boss 9b (fixed in the axial direction). In this manner, the outer ring 5b of the lower bearing 5 is fixed to the motor casing that is also configured with the motor cover 9a and the boss 9b. The ball 5c is held between the inner ring 5a and the outer ring 5b of the lower bearing 5.

Next, the holding structure for the upper bearing 4 will be described in detail.

Unlike the lower bearing 5, the upper bearing 4 is not fixed up and down in the axial direction, and is held by the rotor 3 and the stator 7 only in the radial direction (radial direction) perpendicular to the axial direction.

FIG. 4 is an enlarged view of a portion indicated by a symbol C in FIG. As shown in FIG. 4, the upper bearing 4 is held so as to be sandwiched between the bearing holding portion 3a of the rotor 3 and the bearing holding portion 9d of the motor cover 9a.

In FIG. 4, the upper bearing 4 is shown in the same dimensions as the lower bearing 5 shown in FIG. 3, but the actual size of the lower bearing 5 is larger than that of the upper bearing 4 as shown in FIG. In the present invention, the lower bearing 5 provided on the load shaft (load side) on the output shaft 11 side of the motor 1 is larger than the upper bearing 4 provided on the opposite load side where the output shaft 11 side force is also separated. Is used. By doing so, the durability of the lower bearing 5 to which a higher load than the upper bearing 4 is applied when a load is applied to the motor can be improved.

As shown in FIG. 4, in the motor 1 according to the first embodiment, the diameter for absorbing the dimensional variation of parts between the inner ring 4a of the upper bearing 4 and the bearing holding portion 3a of the rotor 3 is absorbed. A directional gap D is provided. By providing this clearance D, the radial dimension variation of the inner ring 4a or outer ring 4b of the upper bearing 4, the bearing holding part 3a of the rotor 3 and the motor cover It is possible to deal with dimensional variations in the radial direction of the bearing holding portion 9d of 9a.

[0027] If there is a gap D, even if a load is applied to the motor 1, the contact between the inner ring 4a of the upper bearing 4 and the bearing holding portion 3a of the rotor 3 is relaxed and added to the inner ring 4a of the upper bearing 4. The load can be reduced. For this reason, it is possible to improve wear resistance and extend the life.

[0028] If the gap D is simply provided while applying a force, abnormal noise is generated as described above.

Therefore, as a first feature of the present invention, the buffer member 12 is provided in the gap D. Even if this cushioning member 1 2 becomes a cushion and the rotor 3 is eccentric during driving and the bearing holding part 3a swings toward the inner ring 4a side of the upper bearing 4, the bearing holding part 3a and the inner ring 4a of the upper bearing 4 It is possible to suppress the generation of abnormal noise that does not collide directly.

[0029] Since the shock when the bearing holding portion 3a of the rotor 3 swings toward the inner ring 4a side of the upper bearing 4 is mitigated by the buffer member 12, for example, the inner ring 4a of the upper bearing 4 and the rotor 3 The wear resistance of the bearing holder 3a can be improved.

FIG. 4 shows an example in which the buffer member 12 is formed by providing a gap D between the bearing holding portion 3a (rotor 3 side) of the rotor 3 and the inner ring 4a of the upper bearing 4. However, the buffer member 12 may be formed by providing a gap D between the bearing holding portion 9d (stator 7 side) of the motor cover 9a and the outer ring 4b of the upper bearing 4.

FIG. 5 is a view showing an example of the buffer member 12 shown in FIG. 4, and shows an enlarged view of a portion indicated by reference symbol C in FIG. 1, as in FIG. In the example shown in FIG. 5, a groove 3c is formed on the outer periphery of the bearing holding portion 3a of the rotor 3, and an O-ring 12a, which is an elastic member, is fitted into the groove 3c to serve as a buffer member. The O-ring 12a has a cross-sectional diameter that maintains the gap D as shown in FIG.

[0032] Thereby, even if the bearing holding portion 3a swings toward the inner ring 4a side of the upper bearing 4 due to the eccentricity of the rotor 3, the O-ring 12a becomes a cushion and the bearing holding portion 3a and the inner ring 4a of the upper bearing 4 Occurrence of abnormal noise that does not collide directly can be suppressed. Even if the O-ring 12a deteriorates, it is easy to maintain it by replacing it with a new O-ring.

FIG. 6 is a view showing another example of the buffer member 12 shown in FIG. 4, and shows an enlarged view of a portion indicated by reference symbol C in FIG. 1, as in FIG. In the example shown in Fig. 6, the panel member has a V-shaped cross section. 12b is disposed along the outer periphery of the bearing holding portion 3a to serve as a buffer member. The panel member 12b is an elastic member having elasticity in the radial direction while maintaining the gap D as shown in FIG.

[0034] Thereby, even if the bearing holding portion 3a swings to the inner ring 4a side of the upper bearing 4 due to the eccentricity of the rotor 3, the panel member 12b becomes a cushion and the bearing holding portion 3a and the inner ring 4a of the upper bearing 4 directly Generation of abnormal noise that does not collide can be suppressed.

[0035] It should be noted that the buffer member 12 in the present invention is an elastic member that can alleviate the impact when the bearing holding portion 3a swings toward the inner ring 4a side of the upper bearing 4 due to the eccentricity of the rotor 3. The configuration is not limited to those shown in FIG. 5 and FIG.

5 and 6, the force shown in the example in which the O-ring 12a and the panel member 12b are provided between the inner ring 4a of the upper bearing 4 and the bearing holding portion 3a of the rotor 3 is shown. The outer ring 4b and the bearing holding portion 9d of the motor cover 9a may be provided.

[0037] As described above, according to the first embodiment, the buffer member 12 is installed in the gap D formed between the bearing holding portion 3a of the rotor 3 and the inner ring 4a of the upper bearing 4. The impact of collision due to the radial vibration of the rotor 3 when the motor 1 is driven can be absorbed, the generation of abnormal noise can be reduced, and the impact on the inner ring 4a of the upper bearing 4 can be mitigated.

[0038] Embodiment 2.

In the second embodiment, as shown in the first embodiment, the rotor rotates with a magnetic field that is not uniform in the radial direction, and a motor having a gap D between the rotor and the bearing is connected to the rotor. Drive control is performed at a drive frequency high enough to mitigate collisions with bearings.

FIG. 7 is a block diagram showing the configuration of the motor drive system according to the second embodiment of the present invention. In the figure, motor 1 is the motor shown in the first embodiment. The drive device 13 is driven by supplying current to the motor 1 in accordance with a command from the drive control device 14. The drive control device 14 provides the drive device 13 with a drive frequency that is high enough to mitigate the collision between the bearing holding portion 3a of the rotor 3 and the inner ring 4a of the upper bearing 4, that is, in a frequency range that can reduce the number of collisions. Set to control motor 1 drive. In the example of FIG. 7, the drive device 13, the drive control device 14, and the motor 1 are shown as separate devices, but the drive device 13 and the drive control device 14 are used as drive circuits. It can be built into the motor 1 or can be built into the external control device (not shown) that controls the drive control device 14.

FIG. 8 is a view for explaining the movement of the rotor when the motor of the first embodiment is driven, and rotates the bearing holding portion 3 a of the rotor 3 and the inner ring 4 a of the upper bearing 4. A cross section cut by a plane perpendicular to the axis is shown. In a normal DC motor, a low driving frequency is set so that the rotation of the rotor does not deteriorate (for example, around 200 Hz). When the motor 1 of the combination of the rotor 8 pole stator 9 pole shown in the first embodiment is rotated at this drive frequency, the rotor is rotated in 6 directions of 1 rotation as shown in FIG. 3 is attracted and rotated to a hexagonal shape, and at each apex, the inner ring 4a of the upper bearing 4 is contacted to generate an abnormal noise.

[0042] When the drive frequency is made higher than the normal drive frequency, the rotor 3 tries to rotate to the next apex by energizing the next energizing coil before reaching each apex. In other words, as the drive frequency is increased, the number of collisions per rotation gradually decreases by 6 times.

Therefore, in the drive control device 14 according to the second embodiment, the drive device 13 has a drive frequency high enough to alleviate the collision between the bearing holding portion 3a of the rotor 3 and the inner ring 4a of the upper bearing 4. Set and rotate motor 1. For example, if the normal driving frequency is about 200 Hz, in the second embodiment, the motor 1 is driven at a driving frequency of about 500 Hz. As a result, the degree of contact with the bearing at each apex is reduced, and the occurrence of abnormal noise can be reduced. In the example shown in FIG. 8, the case where the driving frequency is increased until the number of times of collision in one rotation of the rotor 3 reaches SO times as indicated by a dashed line.

It should be noted that the drive frequency set by the drive control device 14 is, for example, as shown in FIG. 8, when the rotor 3 collided with Z rotation 6 times due to radial deflection, 5 times Z rotation, 4 times Z rotation, 3 times The frequency range in which the number of collisions in one rotation of the rotor 3 decreases as the frequency increases, such as Z rotation (impact between the bearing holder 3a of the rotor 3 and the inner ring 4a of the upper bearing 4) If the frequency range is enough to alleviate the collision).

As described above, according to the second embodiment, the motor 1 shown in the first embodiment is driven. When moving, the bearing 3 of the rotor 3 and the inner ring 4a of the bearing 4 are controlled by controlling the drive at a driving frequency high enough to mitigate the collision of the rotor 3 attracted in the radial direction with the bearing 4. The number of times of contact is reduced and the generation of abnormal noise can be suppressed.

In the second embodiment, the drive control of the motor 1 according to the first embodiment has been described as an example. However, as shown in the first embodiment, the rotor is generated with a nonuniform magnetic field in the radial direction. It is also possible to control the driving of the motor that rotates the motor and does not include the buffer member 12 in the gap D. That is, by controlling the rotation at the drive frequency, the number of contact between the bearing holding portion of the rotor and the bearing can be reduced even in the motor.

Industrial applicability

[0047] As described above, the motor and the drive control apparatus according to the present invention absorbs the impact of the collision due to the radial deflection of the rotor by the buffer member provided on the side of the bearing, thereby providing wear resistance. It is suitable for use in high-power DC motors such as motors for vehicles that are under load.

Claims

The scope of the claims

[1] A rotor having a plurality of magnets whose outer periphery is magnetized, and a stator having a plurality of energizing coils arranged along the outer periphery of the rotor, and generating electricity by energizing the energizing coil. In the motor in which the rotor rotates with a non-uniform magnetic field in the radial direction,

A load-side bearing that fixes one end of the rotor in the axial direction;

An anti-load-side bearing that fixes the other end of the rotor in the radial direction;

A motor comprising a buffer member provided in a radial direction of the anti-load side bearing.

[2] The motor according to claim 1, wherein the buffer member is an elastic member.

3. The motor according to claim 2, wherein the elastic member is a panel member.

[4] The motor according to claim 2, wherein the elastic member is an O-ring.

[5] The motor according to claim 1, wherein the load side bearing is larger than the anti-load side bearing.

[6] A rotor having a plurality of magnets whose outer periphery is magnetized, and a stator having a plurality of energizing coils arranged along the outer periphery of the rotor, and generating electricity by energizing the energizing coil. In a drive control device for driving and controlling a motor in which the rotor rotates with a magnetic field that is uneven in the radial direction,

A drive control device that controls the rotation of the motor at a drive frequency within a range in which a collision with a bearing due to a radial deflection of the rotor can be mitigated.