JP5306808B2 - Motor drive control device for in-vehicle equipment - Google Patents

Description

  The present invention relates to a motor and its drive control device.

  As a conventional noise countermeasure technique when driving a motor, for example, there is one disclosed in Patent Document 1. Japanese Patent Laid-Open No. 2004-133867 reduces noise generated when a member attached to a rotor shaft collides with a bearing when a rotor of a DC (direct current) motor moves in the axial direction during driving.

  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. Even if the bearing of the motor casing and the boss part collide with the movement of the rotor in the axial direction, the impact of the cushion part is reduced.

  Patent Document 2 relates to 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 to be energized based on a position detection signal obtained by the rotation. In this patent document 2, the vibration and noise generated by the operation by the energization can be reduced by controlling the energization at a frequency that avoids the resonance of the rotor.

JP 2000-32706 A Japanese Patent Laid-Open No. 11-113281

  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 (rotor 8 In the pole-stator 9 pole), the magnetic field generated when the energizing coil is energized generates non-uniform forces that attract the rotor in the radial direction. For this reason, the rotor swings in the radial direction. On the other hand, a motor having a rotor 8-pole-stator 9-pole structure can achieve high output, is easy to manufacture, and is relatively easy to use.

  Further, in the structure in which both ends of the rotor are held by the bearings, a radial gap is provided between the bearing and the stator side or the rotor side in order to cope with the dimensional variation of the parts. If this gap exists, even if a load is applied to a high-power DC motor such as a vehicle motor, contact between the bearing and the stator side or the 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 extend the life, a structure in which the gap is provided is necessary.

  However, if a motor with a combination of rotor 8 poles-stator 9 poles, etc., is used that has a radial clearance between the bearing and the stator or rotor side, abnormal noise is generated during driving. I found out that As a result of the research and analysis of this factor by the inventors of the present invention, the rotor swings in the radial direction by the gap due to the uneven force generated in the radial direction when energized, and the bearing and the stator side or the rotor side are It has been found that this is due to contact.

  With respect to the problems caused by such radial deflection of the rotor, it is possible to obtain an effect even if the technique for abnormal noise generated by the axial movement of the rotor disclosed in Patent Document 1 is applied. Can not. Further, since the above-mentioned problem occurs due to a structural factor of the motor, the countermeasure by the energization control as in Patent Document 2 is not effective.

  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 uneven in the radial direction, a rotor is provided by installing a buffer member on the side of the bearing. An object of the present invention is to obtain a motor that can reduce the occurrence of abnormal noise by absorbing the collision with the bearing due to the radial deflection of the bearing and reduce the impact on the bearing.

  The present invention also provides a bearing control by controlling the driving at a driving frequency high enough to alleviate the collision of the rotor attracted in the radial direction with the bearing when driving the motor whose rotor swings in the radial direction during driving. An object of the present invention is to obtain a drive control device that can reduce the occurrence of abnormal noise by reducing the contact with the motor.

A motor drive control device for an in-vehicle device 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. In a drive control device for driving and controlling a motor in which the rotor rotates with a non-uniform magnetic field generated by energization of the energizing coil, a driving frequency at which a collision with the bearing due to the radial deflection of the rotor occurs In this case, the rotation of the motor is controlled at a driving frequency higher than the driving frequency so that the number of times the rotor collides with the bearing is reduced .

According to the present invention, the rotor includes a magnet having a plurality of magnets whose outer circumferences are magnetized, and the stator having a plurality of energizing coils disposed along the outer circumference of the rotor. In a drive control device for driving and controlling a motor in which the rotor rotates with a generated magnetic field that is not uniform in the radial direction, when the driving frequency is such that a collision with the bearing due to radial deflection of the rotor occurs, the rotor The rotation of the motor is controlled at a driving frequency that is higher than the driving frequency so that the number of times the motor collides with the bearing can be reduced. is there.

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.

  The screw 10 disposed on the opposite side of the output end of the output shaft 11 is inserted into the screw hole provided in the rotor 3 described above. When the rotor 3 is rotationally driven, the rotational force is transmitted to the output shaft 11 via the screw 10 and the output shaft 11 is prevented from rotating, so that the rotational force of the rotor 3 is converted into axial direct power. Is done.

  The stator 7 is obtained by winding a current-carrying coil around a stator (iron core) 7a disposed so as to surround the rotor 3 in a motor cover (motor housing) 9a. Here, nine stators 7a are disposed so as to surround the rotor 3, and energization coils are wound around the stators 7a, respectively, and NS magnetization is performed to nine 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 make visual recognition of the relationship between a stator and a rotor, description of the energization coil in a stator is abbreviate | omitted. 2A and 2C, unlike the motor 1 according to the first embodiment, the rotor 3 has a 12-pole magnetic pole and the stator 7 has 9 energizing coils (rotor). 2 (b) and FIG. 2 (d) show the motor 1 according to the first embodiment, showing a rotor 8 pole-stator 9 pole motor. Yes.

  2 (a) and 2 (b) show the situation when power is supplied from the U phase to the V phase, and FIGS. 2 (c) and 2 (d) show the current supplied from the U phase to the W phase. Shows the situation when As shown in FIG. 2, when the energizing coil of the stator is energized, the stator (iron core) is magnetized and a force attracting the permanent magnetic pole of the rotor is generated. At this time, as shown in FIGS. 2 (a) and 2 (c), in the rotor 12-pole / stator 9-pole motor, a magnetic field is uniformly generated by energizing the energizing coil. The force attracting in the direction works equally in each direction (directions indicated by arrows in FIGS. 2 (a) and 2 (c)), and the rotor is not eccentric.

  On the other hand, if the rotor 8 poles-stator 9 poles are used as in the motor 1 of the first embodiment, a magnetic field that is uneven in the radial direction is generated by energization of the energizing coils, and the rotor 3 is moved in the radial direction. The force attracted to the stator 7 side is applied unevenly (force in the direction indicated by an arrow in FIGS. 2B and 2D). As a result, the rotor 3 swings in the radial direction during driving, and the bearing holding portion 3a comes into contact with the inner ring 4a of the upper bearing 4 to generate abnormal noise.

  Therefore, in the first embodiment, as shown in FIG. 1, a buffer member 12 is provided in the gap between the bearing holding portion 3 a of the rotor 3 and the inner ring 4 a of the upper bearing 4 to suppress the generation of abnormal noise. 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 for holding the rotating shaft are mounted on both ends of the rotor 3.

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). The outer ring 5b of the lower bearing 5 is fixed vertically 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 way, the outer ring 5b of the lower bearing 5 is fixed to the motor casing composed of the motor cover 9a, the boss 9b and the like. A ball 5c is held between the inner ring 5a and the outer ring 5b of the lower bearing 5.

Next, the holding structure of 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 but 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 described with the same size as the lower bearing 5 shown in FIG. 3, but actually, the size of the lower bearing 5 is larger than that of the upper bearing 4 as shown in FIG. 1.
In the present invention, the lower bearing 5 provided on the load shaft side (load side) on the output shaft 11 side of the motor 1 uses a bearing larger than the upper bearing 4 provided on the opposite load side away from the output shaft 11 side. . 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 radial gap D for absorbing the dimensional variation of parts between the inner ring 4 a of the upper bearing 4 and the bearing holding portion 3 a of the rotor 3. Is provided. By providing this gap D, it is possible to deal with variations in the radial dimension of the inner ring 4a or outer ring 4b of the upper bearing 4 and variations in the radial direction of the bearing holding part 3a of the rotor 3 and the bearing holding part 9d of the motor cover 9a. can do.

  Further, 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 the load applied to the inner ring 4a of the upper bearing 4 is reduced. can do. For this reason, it is possible to improve the wear resistance and extend the life.

However, if only the gap D is provided, abnormal noise is generated as described above.
Therefore, the buffer member 12 is provided in the gap D as a first feature of the present invention. Even if the buffer member 12 serves as a cushion and the rotor 3 is eccentric during driving and the bearing holding portion 3a swings toward the inner ring 4a side of the upper bearing 4, the bearing holding portion 3a and the inner ring 4a of the upper bearing 4 directly collide with each other. The generation of abnormal noise can be suppressed.

  Further, 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 reduced by the buffer member 12, for example, the inner ring 4a of the upper bearing 4 and the bearing holding of the rotor 3 are held. The wear resistance of the portion 3a can be improved.

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

  FIG. 5 is a diagram illustrating an example of the buffer member 12 illustrated in FIG. 4, and illustrates an enlarged view of a portion indicated by reference numeral C in FIG. 1 as in FIG. 4. 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.

  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 acts as a cushion and the bearing holding portion 3a and the inner ring 4a of the upper bearing 4 collide directly. The generation of abnormal noise can be suppressed. Further, even if the O-ring 12a deteriorates, it may be replaced with a new O-ring, and maintenance is easy.

  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 numeral C in FIG. In the example shown in FIG. 6, a spring member 12b having a V-shaped cross section is disposed along the outer periphery of the bearing holding portion 3a to serve as a buffer member. The spring member 12b is an elastic member having elasticity in the radial direction while maintaining the gap D as shown in FIG.

  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 spring member 12b acts as a cushion and the bearing holding portion 3a and the inner ring 4a of the upper bearing 4 collide directly. The generation of abnormal noise can be suppressed.

  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, as shown in FIGS. It is not limited to the configuration shown in FIG.

  5 and 6 show an example in which the O-ring 12a and the spring member 12b are provided between the inner ring 4a of the upper bearing 4 and the bearing holding portion 3a of the rotor 3, the outer ring 4b of the upper bearing 4 is shown. And a bearing holding portion 9d of the motor cover 9a.

  As described above, according to the first embodiment, the buffer member 12 is installed in the gap D formed between the bearing holding portion 3 a of the rotor 3 and the inner ring 4 a of the upper bearing 4. The impact of the collision due to the radial vibration of the rotor 3 at the time is 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.

Embodiment 2. FIG.
In the second embodiment, as shown in the first embodiment, the rotor is rotated by 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 replaced with a rotor bearing. The drive control is performed at a drive frequency that is high enough to mitigate the collision with the motor.

  FIG. 7 is a block diagram showing a configuration of a motor drive system according to Embodiment 2 of the present invention. In the figure, a motor 1 is the motor shown in the first embodiment. The drive device 13 supplies current to the motor 1 to drive it according to a command from the drive control device 14. The drive control device 14 sets a drive frequency in the drive device 13 so that the collision between the bearing holding portion 3a of the rotor 3 and the inner ring 4a of the upper bearing 4 can be mitigated, that is, in a frequency range where the number of collisions can be reduced. The drive of the motor 1 is controlled.

  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 may be incorporated in the motor 1 as a drive circuit. Alternatively, it may be incorporated in an external control device (not shown) that controls the drive control device 14.

  FIG. 8 is a diagram for explaining the movement of the rotor when the motor of the first embodiment is driven. The bearing holding portion 3a of the rotor 3 and the inner ring 4a of the upper bearing 4 are surfaces perpendicular to the rotation axis. The cross section cut off by is shown. In a normal DC motor, a low driving frequency is set such that the rotation of the rotor does not deteriorate (for example, around 200 Hz). When the motor 1 having the combination of rotor 8 poles-stator 9 poles shown in the first embodiment is rotated at this driving frequency, the rotor 3 is rotated in 6 directions in one rotation as shown in FIG. Are attracted and rotated into a hexagonal shape, and each of the apexes contacts the inner ring 4a of the upper bearing 4 to generate noise.

  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 the apex. That is, as the drive frequency is increased, the number of collisions per rotation gradually decreases from 6 times.

  Therefore, in the drive control device 14 according to the second embodiment, the drive device 13 is set to 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. The motor 1 is rotated. 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 vertex is reduced, and the occurrence of abnormal noise can be reduced. In the example shown in FIG. 8, the drive frequency is increased until the number of collisions in one rotation of the rotor 3 becomes zero as shown by a one-dot broken line.

  The drive frequency set by the drive control device 14 is, for example, as shown in FIG. 8, when the rotor 3 collided at 6 times / rotation due to radial deflection of the rotor 3, 5 times / rotation, 4 times / rotation, The frequency range in which the number of collisions in one rotation of the rotor 3 decreases as the frequency increases, such as three times / rotation (the degree to which the collision between the bearing holding portion 3a of the rotor 3 and the inner ring 4a of the upper bearing 4 can be mitigated). Frequency range).

  As described above, according to the second embodiment, when driving the motor 1 shown in the first embodiment, it is high enough to alleviate the collision of the rotor 3 attracted in the radial direction with the bearing 4. By performing drive control at the drive frequency, the number of times of contact between the bearing holding portion 3a of the rotor 3 and the inner ring 4a of the bearing 4 is reduced, and 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 rotated by a magnetic field that is not uniform in the radial direction. You may control the drive of the motor which does not provide the buffer member 12 in the clearance 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 also in the motor.

  As described above, the motor and the drive control device according to the present invention improve the wear resistance by absorbing the impact of the collision caused by the radial vibration of the rotor by the buffer member installed on the side of the bearing. In addition, since it has been possible to extend the service life, it is suitable for use in a high-output DC motor such as a vehicle motor that is loaded.

It is sectional drawing which shows the structure of the motor by Embodiment 1 of this invention. It is sectional drawing which shows the eccentricity of the rotor at the time of a drive. It is an enlarged view of the part shown with the code | symbol B in FIG. It is an enlarged view of the part shown with the code | symbol C in FIG. It is a figure which shows an example of a buffer member. It is a figure which shows the other example of a buffer member. It is a block diagram which shows the structure of the motor drive system by Embodiment 2 of this invention. It is a figure for demonstrating the motion of the rotor at the time of a drive.

Explanation of symbols

1 Motor, 2 Permanent magnet, 3 Rotor, 3a, 9d Bearing holding part, 3b, 9c Stepped part, 3c Groove part, 4 Upper bearing, 4a, 5a Inner ring, 4b, 5b Outer ring, 4c, 5c Ball, 5 Lower bearing, 6 Holding mechanism, 7 Stator, 7a Stator, 8 Preload member, 9a Motor cover (motor housing), 9b Boss (motor housing), 10 Screw hole, 11 Output shaft, 12 Buffer member, 12a O-ring, 12b Spring Member, 13 Drive device, 14 Drive control device.

Claims (3)

Radial direction generated by energizing the energizing coil, comprising a rotor having a magnet whose outer periphery is magnetized in plural, and a stator having a plurality of energizing coils disposed along the outer periphery of the rotor In a drive control device for driving and controlling a motor in which the rotor rotates with an uneven magnetic field,
When the driving frequency is such that the collision with the bearing due to the radial deflection of the rotor occurs, the rotation of the motor with a driving frequency higher than the driving frequency is reduced so that the number of times the rotor collides with the bearing is reduced. The motor drive control device for in- vehicle devices characterized by controlling. The motor drive control device for in- vehicle equipment according to claim 1, wherein the motor is a DC brushless motor. The motor is provided in a radial direction of a load side bearing that fixes one end side of the rotor in the axial direction, an anti-load side bearing that fixes the other end side of the rotor in a radial direction, and the anti-load side bearing. The motor drive control device for in- vehicle devices according to claim 1, further comprising a buffer member.

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