JP6155456B2 - Electric power steering motor - Google Patents

Description

  The present invention relates to a motor for an electric power steering device that assists an operating force of a steering wheel of a vehicle.

  Conventionally, Patent Document 1 describes an electric power steering apparatus, and FIG. 15 shows an electric power steering apparatus motor (hereinafter, abbreviated as an electric motor) having a similar configuration. An electric motor 100 shown in FIG. 15 is rotatable by a cylindrical yoke 1, two permanent magnets 2 fixed in opposition to the yoke 1 and arranged in the circumferential direction, and a bearing 3 in the yoke 1. A shaft 4 provided on the shaft 4, an armature 5 fixed to the shaft 4, a commutator 6 fixed to an end of the shaft 4 and composed of a plurality of copper segments 16, and a surface of the commutator 6 And a brush 8 in contact with the elastic force of the spring 7.

The amateur 5 includes a core 9 having a plurality of slots 11 extending in the axial direction, and a winding 10 formed by winding a conductive wire around the slot 11 in a double winding manner.
In the electric motor 100 of the two-pole, heavy winding method, the armature 5 rotates together with the shaft 4 due to electromagnetic action by supplying current to the winding 10 from the outside via the brush 8 in contact with the segment 16.

  Since the electric motor 100 is mainly used for a small displacement vehicle having a relatively light weight, the assist torque of the electric motor 100 is small. Therefore, the operation sound of the electric motor 100 is extremely small and even in the passenger compartment. The size was almost unnoticeable.

  By the way, due to social trends such as low fuel consumption and reduction of exhaust gas, DC motors are used instead of hydraulic power steering devices to reduce fuel consumption and weight even for heavy, medium and large displacement vehicles. Power steering devices are beginning to be adopted. In this case, an electric motor with a large torque is required, but if it is designed with a two-pole, double-winding system, the motor will have a large physique. Multipolarization is required.

  16 and 17 show two-pole, 14-slot DC motor (hereinafter abbreviated as 2-pole motor) and 4-pole, 21-slot DC motor (hereinafter, 4-pole motor) as an example of a multi-pole machine. Abbreviated).). In this figure, the inventor of the present application has obtained a difference in magnetic attraction force acting on an armature when the armature is operated at an eccentric position in a two-pole motor and a four-pole motor by magnetic field analysis. In the figure, the symbol * indicates the stator center, that is, the original center of rotation, and the symbol X indicates the center of rotation at the time of eccentricity. As can be seen from this figure, it can be seen that the 4-pole motor is more susceptible to vibration and noise than the 2-pole motor.

That is, when the force acting on the armature when the same amount of eccentricity (eccentricity of 0.1 mm) is determined in each direction from the eccentric direction angle of 0 degrees to 360 degrees starting from the center position of the original amateur is 2 In the case of a pole motor, a magnetic attractive force of about 0.45N is applied in the eccentric direction, whereas in the case of a 4-pole motor, a magnetic attractive force of about 2.7N (6 times that of a two-pole motor) is applied in the eccentric direction. Works. In a two-pole motor, the directionality of magnetic attraction force due to eccentricity is noticeable, and when it is decentered in the direction between the poles (eccentric direction angle 90 degrees, 270 degrees), the pole center direction (eccentric direction angle 0 degrees, 180 degrees) In comparison with the case where the force is eccentric, the magnetic attraction force of about twice (0.45 / 0.21) acts when the force in the eccentric direction is compared. On the other hand, no significant directionality is seen in the 4-pole motor. That is, the force with respect to the eccentric direction is about 2.7 N at all angles from the eccentric direction angle of 0 degrees to 360 degrees. This means that “the 2-pole motor has a stable direction with respect to the eccentricity. This means that there is no stable direction in the motor, and this difference is related to the difference in vibration and noise.
Thus, in order to reduce the size and increase the torque, it is necessary to increase the number of poles such as quadrupole, but problems of vibration and noise remain.

JP-A-8-258730

By the way, in order to cope with downsizing and higher torque, as a winding method in the case of multipolarization, a wave winding type amateur can be considered in addition to the heavy winding method. In the double winding, the number of brushes is generally the same as the number of poles, but in the wave winding, two brushes are generally provided.
FIG. 18 and FIG. 19 are diagrams showing the magnetic attraction force acting on an armature having four poles and 21 slots as an example of multipolarization. FIG. 18 is a double winding, four brush method, and FIG. 19 is a wave winding, two brush method. Shows the case.
When the two figures are compared, the magnetic attractive force acting on the armature when the armature rotates by one slot of the core is always a constant radial outward direction in the case of the wave-wound armature as shown by the arrow a. On the other hand, in the case of an amateur with multiple windings and 21 slots, it fluctuates in the circumferential direction as shown by the arrow b. There was a problem that it was likely to occur.

In addition, in the case of multi-pole, odd-numbered slot, and double winding method, it is induced between the circuits of the windings of the amateur due to the effects of yoke magnetic circuit imbalance, amateur eccentricity, uneven current flowing through the brush, work error, etc. There is a difference in electromotive force, and a circulating current flows through the brush in the armature. As a result, the brush rectifying action deteriorates, the commutation spark generated from the brush increases, the brush and commutator become hot, the service life decreases, the torque There is also a problem that the operating noise increases due to the increase in ripple and the combined action thereof.
On the other hand, in the case of the multi-pole, odd-numbered slot, wave winding method, there are problems such that torque ripple is increased and the number of parallel circuits is reduced, so that the winding becomes thick and the workability is deteriorated.

  An object of the present invention is to solve the above-described problems, and it is possible to reduce the operating noise, reduce the torque ripple, and improve the steering feeling of the driver holding the steering wheel. The object is to obtain a motor for a power steering device.

A motor for an electric power steering apparatus according to the present invention is a motor for an electric power steering apparatus that is controlled using a vehicle speed signal and a steering torque signal and is driven by PWM (pulse width modulation) to assist an operation force of a steering wheel of a vehicle. A motor attached to a column in a vehicle compartment of the vehicle, comprising a yoke and a permanent magnet of 4-pole ferrite fixed to the inner wall surface of the yoke at equal intervals in the circumferential direction And a shaft provided rotatably in the yoke, and 22 slots formed on the outer peripheral surface of the core and extending in the axial direction on the outer periphery of the core. An armature having a winding wound by a double winding method, and 22 segments fixed to the end of the shaft and having a hook. The formed commutator and the magnetic center of the magnetic flux distribution of the field part when the permanent magnet is in contact with the surface of the commutator and equally spaced in the circumferential direction and the permanent magnet is not affected by the armature reaction And four brushes arranged at points , and the energization current of the winding is controlled by the PWM drive.
The motor for an electric power steering apparatus according to the present invention is a motor for an electric power steering apparatus that is controlled using a vehicle speed signal and a steering torque signal and is PWM driven to assist an operation force of a steering wheel of the vehicle. A motor mounted on a column in a vehicle interior of the vehicle, comprising a yoke, and a field portion composed of a permanent magnet of 4-pole ferrite fixed to the inner wall surface of the yoke at equal intervals in the circumferential direction; A shaft that is rotatably provided in the yoke, and 26 slots that are fixed to the shaft and that extend in the axial direction on the outer peripheral surface of the core, are enamel-coated round conductor wires that are double-wrapped. A rectifier composed of 26 segments, having an armature wound around and having a hook fixed to the end of the shaft. When, in contact with the surface of the commutator, at equal intervals in the circumferential direction, the permanent magnet is disposed in the magnetic central point of the magnetic flux distribution of the field magnet part when not under the influence of armature reaction Four brushes, and the energization current of the winding is controlled by the PWM drive.

The total radial magnetic attraction force for amateurs is zero, and there is no rotational vibration that causes operating noise, which can reduce operating noise and torque ripple, and the steering feel of the driver holding the steering wheel. Will improve.
Further, since the number of brushes and the number of poles are the same, the current density of the brushes is lowered, the usable time in the so-called “stationary, end-fitting state” is increased, and the convenience of the motor for the electric power steering apparatus is increased. Improves.
In addition, since the commutator has a hook, it is possible to easily perform mechanical winding of a conductive wire.

It is sectional drawing inside a motor for power steering devices of this invention. It is a principal part enlarged view of FIG. 3A is a developed front view of the pressure equalizing body of FIG. 1, and FIG. 3B is a side view of FIG. 3A. 4A is a front view of the base of the pressure equalizing body in FIG. 1, and FIG. 4B is a side view of FIG. 4A. It is a front view of the terminal of the pressure equalization main body of FIG. It is a front view of the insulation board of the pressure equalizing main body of FIG. It is a motor for electric power steering apparatus of this invention, Comprising: It is a figure for demonstrating the magnetic attraction force which acts on the amateur in the case of 4 poles, heavy winding, 4 brushes, and 22 slots. It is a front view which shows the other example of a terminal. It is a sectional side view which shows the other example of an amateur. It is a principal part enlarged view of FIG. It is a figure which shows the relationship between the number of terminals and an auditory evaluation score. It is a figure which shows the relationship between the motor output class in each motor, and a motor operation sound. It is a perspective view which shows a mode when the motor for electric power steering apparatuses is attached to the pinion. It is a figure which shows the relationship between a control gain, a torque fluctuation, and the magnetic attraction force of radial direction. It is sectional drawing of the motor for the conventional electric power steering apparatus. It is a figure for demonstrating the magnetic attraction force of a 2 pole motor and a 4 pole motor. It is a figure for demonstrating the magnetic attraction force of a 2 pole motor and a 4 pole motor. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of the motor for electric power steering apparatuses of 4 poles, heavy winding, 21 slots, and 4 brush systems. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of the motor for electric power steering apparatuses of 4 poles, a wave winding, the number of slots 21, and 2 brush system. It is a block diagram of a control unit. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of a motor for electric power steering devices of 4 poles, heavy winding, 24 slots, and 4 brush system. It is a figure for demonstrating the electromagnetic attraction force of the motor for electric power steering apparatuses of 4 poles, heavy winding, 20 slots, and 4 brush system. It is a figure for demonstrating the electromagnetic attraction force of the motor for electric power steering devices of 4 poles, heavy winding, 26 slots, and 4 brush system. It is a figure for demonstrating the electromagnetic attraction force of the motor for electric power steering apparatuses of 4 poles, heavy winding, 28 slots, and 4 brush system. It is a figure which shows the relationship of the torque ripple of each electric power steering apparatus motor of 4 poles, heavy winding, and the number of slots 20, 21, 22, 24, 26, 28, and 4 brush system, and electromagnetic attraction force. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of the motor for electric power steering apparatuses of 6 poles, heavy winding, 25 slots, and 6 brush systems. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of the motor for electric power steering apparatuses of 6 poles, heavy winding, 24 slots, and 6 brush systems. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of the motor for electric power steering apparatuses of 6 poles, heavy winding, slot number 22, and 6 brush system. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of the motor for electric power steering apparatuses of 6 poles, heavy winding, 26 slots, and 6 brush systems. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of the motor for electric power steering apparatuses of 6 poles, heavy winding, 21 slots, and 6 brush systems. It is a figure for demonstrating the electromagnetic attraction force and torque ripple of the motor for electric power steering devices of 6 poles, heavy winding, 27 slots, and 6 brush systems. It is a figure which shows the torque ripple of each motor for electric power steering devices of 6 poles, heavy winding, and the number of slots 21, 22, 24, 25, 26, 27, and 6 brush system, and the electromagnetic attraction force.

Embodiment 1 FIG.
Hereinafter, an example of a motor for an electric power steering apparatus according to the present invention (hereinafter, abbreviated as an electric motor) will be described.

FIG. 1 is a side sectional view of the internal structure of an electric motor according to the present invention, and FIG. 2 is an enlarged view of a main part of FIG. The electric motor includes a cylindrical yoke 1, a permanent magnet 2 made of ferrite fixed in the yoke 1 at intervals in the circumferential direction, and a bearing 3 that is rotatably provided in the yoke 1. The shaft 4, the armature 20 fixed to the shaft 4, the commutator 6 fixed to the end of the shaft 4 and composed of a plurality of segments 16, and the elasticity of the spring 7 on the surface of the commutator 6. There are provided four brushes 8 which are in contact with each other by force and arranged at equal intervals, and a pressure equalizing body 22 fixed to the shaft 4 between the armature 20 and the commutator 6. In the figure, the yoke 1, the permanent magnet 2, the bearing 3, the spring 7, and the brush 8 are not shown.
The amateur 20 includes a core 9 having 24 slots 11 extending in the axial direction, and a winding 21 formed by winding a conductive wire 19 around the slot 11 in a double winding manner.

  3A is a developed front view of the pressure equalizing main body 22, FIG. 3B is a side view of the pressure equalizing main body 22 of FIG. 3A, and the pressure equalizing main body 22 is formed on the base 23 with the pressure equalizing. Twelve terminals 24 and insulating plates 25 made of copper plates or the like, which are members, are alternately stacked.

  4 (a) and 4 (b) are a front view and a side view of the base 23. In the annular base body 27, twelve pins 26 stand at equal intervals along the circumferential direction. It is installed.

  FIG. 5 is a front view of the terminal 24, which is a pressure equalizing member, and holes 29 are formed in the annular terminal body 28 at equal intervals along the circumferential direction at 24 locations. Further, the terminal main body 28 is provided with pressure equalizing line portions 30a and 30b that face each other and extend outward.

  FIG. 6 is a front view of the insulating plate 25. In this insulating plate 25, holes 32 are formed at equal intervals along the circumferential direction at 24 locations of the annular insulating plate main body 31.

In the electric motor, the pressure equalizing main body 22 is assembled by alternately stacking 12 terminals 24 and 12 insulating plates 25 on the base 23. At this time, each of the terminals 24 is rotated every 15 degrees, the pin 26 of the base 23 is passed through the hole 29 of the terminal 24, and the terminal 24 is fixed to the base 23. Further, the pin 26 of the base 23 is passed through the hole 32 of the insulating plate 25, and the insulating plate 25 is fixed to the base 23. Thereafter, the tip of the pin 26 is caulked to complete the integrated pressure equalizing body 22.
Thereafter, the pressure equalizing body 22 and the commutator 6 are fitted to the shaft 4 in this order. The shaft 4 is formed with a protrusion 14 extending in the axial direction for positioning in the rotational direction. The base 23 and the commutator body 15 made of phenol resin are elastically deformed and engaged with the protrusion 14. It has stopped.

  Next, after the equalizing wire portions 30a and 30b are bent along the hooks 34, the conductors 19 are wound around the core 9 by the mechanical winding with the double winding method to form the winding 21, and the armature 20 is formed. The pressure equalizing wire portions 30a and 30b and the hook 34 are electrically joined at 24 locations simultaneously by fusing or the like.

  The electric motor having the above configuration has four magnetic poles, 24 slots 11, double winding, and four brush system. FIG. 21 shows the magnetic attraction force and torque ripple acting on the armature 20 in this electric motor obtained by the inventor of the present application by magnetic field analysis. As shown in FIG. 18, in the case of an amateur with four poles, heavy windings, and four brushes and having 21 slots, the magnetic attractive force acting on the amateur fluctuates in the circumferential direction, and rotational vibration is likely to occur in the amateur. It can be seen that the operation sound is easy to be generated, whereas in the case of the armature having 24 slots, the magnetic attractive force acting on the amateur is zero and the operation sound caused by the rotational vibration is not generated.

FIG. 7 shows an example of a motor for an electric power steering apparatus according to the present invention. The magnetic attractive force acting on the armature and the torque ripple in the case of 22 poles having four poles and multiple windings and an even number of slots. Is the figure which this inventor calculated | required by the magnetic field analysis.
As can be seen from this figure, even in the case of an armature with 22 slots, the magnetic attractive force acting on the amateur is zero, and it can be seen that there is no operating noise caused by rotational vibration.
Further, in the case of the wave winding amateur shown in FIG. 19, the torque ripple (pp) indicating the ratio of the torque waveform height difference value to the torque value is 1.37%. In the case of an amateur with 22 slots and a heavy winding, the torque ripple (pp) is 0.876%, which is smaller than that of a wave winding. For this reason, as shown in FIG. 20, the torque ripple of the electric motor 18 driven by PWM (pulse width modulation) is reduced by the motor drive signal from the control unit 13, and the steering feeling of the driver holding the handle 12 is waved. It improves compared with the electric motor of.

  In the pressure equalizing body 22 having the above-described configuration, the annular terminal body 28 is used. However, in order to reduce the amount of copper used as the material, the terminal body 50 of the terminal 52 is made circular as shown in FIG. It may be arcuate.

  Further, as shown in FIGS. 9 and 10, six terminals 24 and insulating plates 25 of the pressure equalizing body 60 are alternately stacked on the base 23, and every other terminal 24 is electrically connected to the hook 34. Alternatively, every other two terminals 24 may be electrically connected.

In order to prevent circulating current flowing in the brush due to the difference in induced electromotive force generated between circuits, it is more effective to increase the number of terminals that are pressure equalization members. Considering this point, the quantity may be reduced.
If the number of terminals is K, the number of core slots is Ns, and the maximum number of brush segments straddling is n, the number of terminals satisfying Ns / (n × 2) ≦ K ≦ Ns The sound was found to be small. In other words, FIG. 11 is an evaluation diagram when Ns = 22 and n = 3. The evaluation score is a maximum of 10 points, and 6 points or more are acceptable, and the above equation is an equation that satisfies this evaluation point criterion.

  Further, in the electric motor having the above-described configuration, enamel-covered round wire is used as the conducting wire 19 of the winding 21 in order to enable mass production and reduce the manufacturing cost. Even windings cannot be wound in complete alignment, and there is a risk that variations in resistance and inductance between each circuit of the winding will increase. However, the provision of the pressure equalizing main body 22 prevents the circulating current flowing through the brush due to the difference in induced electromotive force generated between the circuits, and thus inconveniences caused by variations in resistance and inductance between the circuits of the windings arise. Absent.

  Further, the electric motor having the above configuration uses the permanent magnet 2 made of ferrite in order to reduce torque ripple having a large correlation with the steering performance. When the field is a winding system, the magnetic flux density is generally higher than that of the permanent magnet, and the rotation direction of the armature is different depending on whether the core slot is at a position facing the magnetic pole or the tooth. The gap magnetic flux density change due to the position change is large, and the torque ripple becomes large. In general, the average magnetic flux density in the case of a ferrite field permanent magnet is about 3 to 4000 gauss, whereas in the case of the winding method, it is about 7 to 8000 gauss. Torque ripple increases, the magnetic attraction force fluctuates greatly at the teeth of the core, and the electromagnetic noise increases. In addition, when a ferrite field permanent magnet is used, it is possible to reduce the size of the electric motor, improve the assembly workability, and reduce the cost.

  Thus, it is effective to use a ferrite field permanent magnet in an electric motor, but in this case, since the magnetic flux density of the field is low, the number of turns of the armature conductor is increased to ensure the torque characteristics. It has become. For this reason, the field magnet is greatly affected by the armature reaction, and the magnetic center point of the magnetic flux distribution of the field magnetic pole is greatly shifted in the direction opposite to the rotation direction of the amateur. In a normal motor, the brush position is shifted from the geometric magnetic pole center position in the rotation direction opposite to the rotation direction of the armature to compensate for the deviation of the magnetic center point, thereby ensuring a good magnetic flux distribution. However, since this electric motor rotates in both the left and right directions, as described above, the brush position is shifted in the opposite direction to the rotation direction of the armature to compensate for the deviation of the magnetic center point to ensure a good magnetic flux distribution. I can't.

  Therefore, in this electric motor, in order to compensate for the deterioration of the magnetic flux distribution, providing the pressure equalizing body 22 in the armature 20 is favorable in combination with the improvement in the balance of the induced voltage of each circuit of the winding. The magnetic flux distribution can be secured, and the following special effects can be obtained.

  (1) Since the operating noise of the electric motor is reduced as shown in FIG. 12, even if the electric motor is attached to the handle column, the driver does not feel uncomfortable operating noise during steering. Since the electric motor can be attached to the column in the vehicle compartment, conventionally, the electric motor 100 is attached to the rack 40 in the engine compartment as shown in FIG. Since the environmental resistance against water and water becomes particularly advantageous, the electric motor can be manufactured at a lower cost.

  (2) Because of the lap winding 4-brush system, torque ripple is reduced, and even when the electric motor is PWM-driven by a motor drive signal from the control unit 13, vibration during driving of the electric motor is applied to the handle 12. Is hardly transmitted, and the steering feeling of the driver is not deteriorated.

  Further, since the torque ripple of the electric motor is reduced, the degree of freedom in designing the PWM drive system of the control unit 13 is increased, the response and controllability with a small current can be improved, and the steering feeling can be further improved. .

  In addition, a steering sound (a sound generated when the electric motor vibrates due to a change in torque caused by a change in current flowing through the armature 20 due to a minute change in the contact state between the brush 8 and the segment 16 with the handle 12 fixed at a certain position. The vibration noise generated between minute displacements corresponding to the backlash of the system when the electric motor is not driven can be reduced. In the conventional wave winding 2-brush system, the torque ripple is large, and thus it is easy to generate the steering noise. However, when the control gain is increased in order to suppress the generation of the steering noise by the control unit 13, FIG. As described above, the torque fluctuation indicating the degree of the holding sound is reduced, but the operating sound (radial magnetic attractive force) is increased, and both the holding sound and the operating sound cannot be suppressed. On the other hand, in the electric motor using the lap winding and the 4-brush method, it is possible to suppress both the steering sound and the operation sound.

(3) Since it is a lap winding and 4-brush system, the current density of the brush 8 can be lowered, and the allowable energization time of the electric motor can be lengthened. Electric motors are frequently used in the so-called “far-off / end-contact” state, in which the handle 12 is turned to the maximum angle when making a U-turn in the garage or at the time of turning the car. Instead, only torque is generated and the electric motor is used in a restrained state. At this time, since the current density of the brush 8 having the severest temperature rise can be lowered, the usable time in the “stationary / end contact state” becomes longer, and the convenience of the electric motor is improved.
Further, the life of the brush 8 is extended, and the reliability and durability of the electric motor are improved.

  (4) Since it is a lap winding and 4-brush system, the cross-sectional area of the conducting wire of the winding 21 can be reduced to almost half under the same performance condition as that of the wave winding, and the conducting wire is easily deformed. Thus, the winding property is improved and the wire diameter is reduced, so that the gap in the slot 11 of the core 9 is reduced, so that the space factor can be increased and the electric motor can be reduced in size. . Therefore, the inertia moment and loss torque of the amateur 20 which are important factors in steering performance can be reduced.

  (5) By improving the balance of the induced electromotive force between the circuits of the windings, torque ripple can be further reduced, torque ripple transmitted to the handle 12 is reduced, and the driver's steering feeling is further improved. be able to.

  (6) Since a good rectifying action can be obtained, the life of the brush 8 is prolonged, the temperature rise of the brush 8 can be suppressed, and the rectified sound (sparking sound) of the brush 8 can be reduced. In addition, since there are few sparks, it is advantageous for radio noise. In particular, there is little influence on radio noise and the like even when it must be attached to a handle column and used near a radio power circuit.

  Further, since the generation of sparks is small, the load of the spring 7 that presses the brush 8 against the commutator 6 can be reduced, so that the loss torque due to the brush pressing can be reduced, and the generation of frictional heat due to the pressing of the brush 8. Can be reduced. Therefore, even with the double winding and the four brush method, it is possible to achieve the same loss torque as compared with the wave winding and the two brush method.

In the above-described embodiment, the motor for an electric power steering apparatus having four poles 24 slots and 22 slots is described. However, the number of slots is not limited to this, and the number of slots is in the radial direction with respect to the amateur. If the number of slots is an even number that does not generate a magnetic attractive force, there is a noise reduction effect.
In addition, if the number is not a multiple of the number of poles, torque ripple can be reduced.

  22 to 24 show the magnetic attractive force and the torque acting on the amateur in the case of a double winding, 4 poles, 20 slots, 4 poles, 26 slots, and 4 poles, 28 slots. It can be seen that no magnetic attractive force in the radial direction is applied. FIG. 25 shows a summary of these results. When the number of slots is selected as an even number or a multiple of the number of pole pairs, no magnetic attractive force is generated in the radial direction. It can be seen that it can be reduced.

Further, the number of poles is not limited to four, but may be four or more, such as six or eight. FIG. 26 to FIG. 31 show examples of double windings, 6 poles, 25 slots, 6 poles, 24 slots, 6 poles, 22 slots, 6 poles, 26 slots, 6 poles, 21 slots, and 6 poles, 27 slots. .
In FIG. 26, since the number of slots is neither an even number nor a multiple of the number of pole pairs, it can be seen that a radial magnetic attractive force acts. Further, in FIG. 27, since the number of slots is a multiple of the number of poles, the torque ring full is large. 28 and 29 show the case where the number of slots is an even number and is not a multiple of the number of poles, and FIGS. 30 and 31 show the case where the number of slots is a multiple of the number of pole pairs and not a multiple of the number of poles. Does not act, and torque ripple is kept small. FIG. 32 summarizes these results. As in the case of four poles, if the number is even or a multiple of the number of pole pairs, no magnetic attractive force is generated in the radial direction. It can be seen that ripple can also be reduced. The same applies to the case of 8 poles or more. When the number of slots is a multiple of the number of pole pairs, the above-described pressure equalizing member can be provided, so that the circulating current can be prevented and the rectifying action can be improved.

As described above, according to the motor for an electric power steering apparatus according to the present invention, in the motor for an electric power steering apparatus that assists the operating force of the steering wheel of the vehicle, the yoke and the 4 fixed to the inner wall surface of the yoke are fixed. A magnetic field portion composed of a permanent ferrite magnet, a shaft rotatably provided in the yoke, and 22 pieces formed on the outer peripheral surface of the core and extending in the axial direction. An armature having a winding formed by winding a conductive wire in a slot by a mechanical winding in a slot; a commutator constituted by a plurality of segments fixed to an end of the shaft and having a hook; Since there are four brushes that are in contact with the surface of the commutator and are arranged at the magnetic center point of the magnetic flux distribution of the field magnet portion, Total suction force is zero, does not occur rotational vibration which causes the operation noise, it is possible to reduce operating noise and torque ripple is also reduced, the steering feeling of the driver is improved gripping the handle.
Further, since the number of brushes and the number of poles are the same, the current density of the brushes is lowered, the usable time in the so-called “stationary, end-fitting state” is increased, and the convenience of the motor for the electric power steering apparatus is increased. Improves.
Moreover, the commutator has a hook, and can easily perform the mechanical winding of the conducting wire.

Further, according to the motor for an electric power steering apparatus according to the present invention, in the electric power steering apparatus motor that assists the operation force of the steering wheel of the vehicle, the yoke and the four-pole ferrite fixed to the inner wall surface of the yoke are provided. A magnetic field portion composed of a permanent magnet, a shaft rotatably provided in the yoke, and 26 slots fixed to the shaft and extending in the axial direction on the outer peripheral surface of the core. An armature having a winding wound by a double winding method with a mechanical winding, a commutator composed of a plurality of segments fixed to the end of the shaft and having a hook, and a commutator of the commutator Since there are four brushes that are in contact with the surface and arranged at the magnetic center point of the magnetic flux distribution of the field part, the total of the magnetic attractive force in the radial direction against the amateur Is zero, does not occur rotational vibration which causes the operation noise, it is possible to reduce operating noise and torque ripple is also reduced, the steering feeling of the driver is improved gripping the handle.
Further, since the number of brushes and the number of poles are the same, the current density of the brushes is lowered, the usable time in the so-called “stationary, end-fitting state” is increased, and the convenience of the motor for the electric power steering apparatus is increased. Improves.
Furthermore, since the commutator has a hook, the mechanical winding of the conducting wire can be easily performed.

According to the motor for an electric power steering apparatus according to the present invention, in the electric power steering apparatus motor that assists the operation force of the steering wheel of the vehicle, the yoke and the 6-pole ferrite fixed to the inner wall surface of the yoke are provided. A magnetic field portion composed of a permanent magnet, a shaft rotatably provided in the yoke, and 21 slots fixed to the shaft and extending in the axial direction on the outer peripheral surface of the core. An armature having a winding wound by a double winding method with a mechanical winding, a commutator composed of a plurality of segments fixed to the end of the shaft and having a hook, and a commutator of the commutator And six brushes disposed at the magnetic center of the magnetic field distribution of the magnetic field in the field portion, so that a radial magnetic attraction force to the amateur Le is zero, does not occur rotational vibration which causes the operation noise, it is possible to reduce operating noise and torque ripple is also reduced, the steering feeling of the driver is improved gripping the handle.
In addition, since the number of brushes and the number of poles is the same, the current density of the brushes is reduced, the usable time in the so-called “stationary, end-contacted state” is increased, and the convenience of the motor for the electric power steering apparatus is increased. Improves.
Moreover, the commutator has a hook, and can easily perform the mechanical winding of the conducting wire.

According to the motor for an electric power steering apparatus according to the present invention, in the electric power steering apparatus motor that assists the operation force of the steering wheel of the vehicle, the yoke and the 6-pole ferrite fixed to the inner wall surface of the yoke are provided. A magnetic field portion composed of a permanent magnet, a shaft rotatably provided in the yoke, and 27 slots fixed to the shaft and extending in the axial direction on the outer peripheral surface of the core. An armature having a winding wound by a double winding method with a mechanical winding, a commutator composed of a plurality of segments fixed to the end of the shaft and having a hook, and a commutator of the commutator And six brushes disposed at the magnetic center of the magnetic field distribution of the magnetic field in the field portion, so that a radial magnetic attraction force to the amateur Le is zero, does not occur rotational vibration which causes the operation noise, it is possible to reduce operating noise and torque ripple is also reduced, the steering feeling of the driver is improved gripping the handle.
In addition, since the number of brushes and the number of poles is the same, the current density of the brushes is reduced, the usable time in the so-called “stationary, end-contacted state” is increased, and the convenience of the motor for the electric power steering apparatus is increased. Improves.
Moreover, the commutator has a hook, and can easily perform the mechanical winding of the conducting wire.

  Further, according to the motor for an electric power steering apparatus according to the present invention, the pressure equalizing member which is electrically joined to the hook and prevents the circulating current flowing in the brush due to the difference in induced electromotive force generated between the circuits in the amateur circuit. Therefore, the circulating current flowing through the brush can be prevented due to the difference in induced electromotive force generated between the amateur circuits, and as a result, the brush rectifying action can be improved, and the rectifying spark generated from the brush can be suppressed. be able to. Moreover, the magnitude | size of each of an operation sound and a torque ripple can be reduced. Furthermore, since the pressure equalizing member and the hook can be electrically joined simultaneously by fusing or the like, manufacturing is easy and manufacturing cost can be reduced.

  Further, according to the motor for an electric power steering apparatus according to the present invention, since the energization current of the winding is controlled by PWM (pulse width modulation) drive, a desired voltage can be applied with reduced power loss. The control unit can be downsized.

  Further, according to the motor for an electric power steering apparatus according to the present invention, since the conducting wire is an enamel-coated round wire, it is easier to mechanize the process of winding the conducting wire around the core, and mass production of amateurs is facilitated. It becomes possible and the manufacturing cost is reduced.

  4 shafts, 6 commutators, 9 cores, 11 slots, 16 segments, 19 conductors, 20 amateurs, 21 windings, 22 pressure equalizing bodies, 24 terminals, 34 hooks.

Claims (3)

In a motor for an electric power steering device that is controlled using a vehicle speed signal and a steering torque signal, is driven by PWM (pulse width modulation), and assists the operation force of the steering wheel of the vehicle.
A motor attached to a column in a vehicle interior of the vehicle,
York,
A field portion composed of a permanent magnet of 4-pole ferrite fixed to the inner wall surface of the yoke at equal intervals in the circumferential direction;
A shaft rotatably provided in the yoke;
An enamel-covered round conductor wire is wound by a double winding method in 22 slots fixed to the shaft and extending in the axial direction on the outer peripheral surface of the core. With amateurs,
A commutator composed of 22 segments fixed to the end of the shaft and having hooks;
4 in contact with the surface of the commutator and arranged at equal intervals in the circumferential direction at the magnetic center point of the magnetic flux distribution of the field portion when the permanent magnet is not affected by the armature reaction. With brushes,
A motor for an electric power steering apparatus, wherein an energization current of the winding is controlled by the PWM drive. In a motor for an electric power steering device that is controlled using a vehicle speed signal and a steering torque signal, is driven by PWM (pulse width modulation), and assists the operation force of the steering wheel of the vehicle.
A motor attached to a column in a vehicle interior of the vehicle,
York,
A field portion composed of a permanent magnet of 4-pole ferrite fixed to the inner wall surface of the yoke at equal intervals in the circumferential direction;
A shaft rotatably provided in the yoke;
An enamel-covered round wire is wound by a double winding method in 26 slots fixed to the shaft and extending in the axial direction on the outer peripheral surface of the core. With amateurs,
A commutator composed of 26 segments fixed to the end of the shaft and having hooks;
4 in contact with the surface of the commutator and arranged at equal intervals in the circumferential direction at the magnetic center point of the magnetic flux distribution of the field portion when the permanent magnet is not affected by the armature reaction. With brushes,
A motor for an electric power steering apparatus, wherein an energization current of the winding is controlled by the PWM drive.   The motor for an electric power steering apparatus according to claim 1 or 2, further comprising a pressure equalizing member that prevents a circulating current flowing through the brush due to a difference in induced electromotive force generated between the circuits in the amateur circuit.

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