JP2005045916A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To offer a steering device which can keep a good steering feeling without ripple of output due to a motor, and besides is small-sized and inexpensive. <P>SOLUTION: This steering device is equipped with a brushless motor 3 which gives torque to a steering system, a steering torque sensor TS1, a resolver 7, a steering torque sensor TS1, and a motor drive control means 8 which controls the rotating operation of the above brushless motor 3, based on the signals from the steering torque sensor TS1 and the resolver 7. The number of the poles of the rotor of the resolver 7 is one larger than the number of the pairs of the stator coils of the brushless motor 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a steering device that reduces a burden of a driver's steering force by a driving force of an electric motor with respect to a steering system of an automobile.

  Conventionally, as a steering device, an electric motor that applies torque to the steering system, a steering input detection means that outputs a detection signal while detecting a steering input by the driver to the steering system, and a rotation state of the electric motor are detected. A steering device comprising: a rotation detection means for outputting the detected motor rotation signal; and a control means for controlling the rotation operation of the electric motor based on the detection signal from the steering input detection means and the motor rotation signal from the rotation detection means. An apparatus is known (see, for example, Patent Document 1).

  In such a steering device, when a steering input is given to the steering system by turning the steering wheel, the steering input detection means outputs a detection signal of the steering input, and the control device receives the detection signal. Based on this, the rotation operation of the electric motor is controlled. The electric motor applies a predetermined torque to the steering system according to the steering input by the driver. Therefore, according to this steering device, the burden of the steering force on the driver's steering wheel is reduced by the torque applied to the steering system by the electric motor.

Further, in this steering apparatus, when the electric motor applies torque to the steering system, the rotation detecting means detects a rotation state such as the rotation angle and angular velocity of the electric motor and outputs the detected electric motor rotation signal. Then, based on the electric motor rotation signal, the control device controls the rotation operation of the electric motor. According to such a steering device, the rotation operation of the electric motor is controlled in accordance with the rotation state such as the rotation angle and angular velocity of the electric motor. For example, the driver slowly rotates the steering wheel, for example, during high-speed driving of an automobile. Regardless of whether the vehicle is moved or when the steering wheel is quickly turned due to a sudden change of course, the driver's steering feeling is maintained well.
Japanese Patent Laid-Open No. 2001-18822 (paragraphs 0012 to 0028, FIG. 1)

  By the way, in such a steering device, since the rotation detecting means is disposed integrally with or near the electric motor, the motor rotation signal output from the rotation detecting means includes the number of poles of the stator coil of the electric motor. In response, periodically generated noise enters. More specifically, for example, in a steering device including an electric motor having a stator coil having nine poles and a resolver (rotation detecting means) having a three-pole rotor, as shown in FIG. The motor noise enters the position of 40 ° × n (n is an integer of 1 to 9) in the tertiary motor rotation signal composed of the wave output voltage and the cosine wave output voltage. Then, the common multiple of the rotation angle (40 °), which is the first position where noise is generated during one rotation of the electric motor, and the rotation angle (120 °), which is the position where the first cycle of the sin wave output voltage is completed. The noise of the electric motor always enters the rotation angle indicated by (120 °, 240 ° and 360 ° (0 °)), that is, the position where the sin wave output voltage is zero. The noise entering such a position has the greatest influence on the motor rotation signal in consideration of the S / N ratio. Therefore, in the steering device, the output (torque) of the electric motor fluctuates due to the noise emphasized at such a specific position, so that the driver's steering feeling is impaired.

  In order to prevent such noise from entering the motor, it is conceivable to cover the wiring for transmitting the motor rotation signal with a shield, or to arrange a shield plate between the motor and the rotation detecting means. Such a steering device has a new problem that its structure is complicated or large. Further, since the number of parts constituting the steering device increases, there arises a problem that the manufacturing cost of the steering device increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a small and inexpensive steering apparatus that can maintain a good steering feeling with little fluctuation in output by an electric motor.

  The invention described in claim 1 for solving the above-described problems is an electric motor that applies torque to a steering system, and a steering input detection that detects a steering input to the steering system by a driver and outputs a detection signal thereof. And a rotation detection means for detecting a rotation state of the electric motor and outputting a detected electric motor rotation signal, based on the detection signal from the steering input detection means and the electric motor rotation signal from the rotation detection means. And a control device for controlling the rotation operation of the electric motor, wherein the electric motor includes a plurality of magnets and a plurality of stator coils each including three phases, and the rotation detection unit includes a plurality of rotation detecting units. And a rotor that rotates in synchronization with the motor and a coil that induces an AC output voltage according to the rotation angle of the rotor. And which is characterized in that the number of poles of the rotor is a number one more than the number of sets of said stator coils.

  In this steering device, when the electric motor rotates, the noise of the electric motor enters the rotation angle for one rotation, that is, a position that is an integral multiple of the rotation angle obtained by dividing 360 ° by the number of poles of the stator coil. On the other hand, the motor rotation signal output from the rotation detection means, that is, the order of the output voltage induced in the coil of the rotation detection means is equal to the number of poles of the rotor. When the output voltage is induced by the coil of the rotation detecting means, the rotation angle of the rotor at which the output voltage becomes zero matches the rotation angle at which the noise of the electric motor enters. The rotation angle is indicated by a common multiple of the rotation angle that is the first position where noise is generated during one rotation of the motor and the rotation angle that is the position where the first cycle of the output voltage (motor rotation signal) is completed. Rotation angle. That is, according to this steering device, since the number of poles of the rotor is set to one more than the number of sets of stator coils, the rotation angle of the rotor at which the output voltage (motor rotation signal) becomes zero The number of locations where the rotation angle at which the noise of the electric motor enters coincides is reduced. Therefore, in this steering device, disturbance due to noise with respect to the motor rotation signal is reduced. In addition, since the disturbance due to noise to the motor rotation signal is reduced, the wiring for transmitting the motor rotation signal is covered with a shield or the shield between the motor and the rotation detection means in order to prevent noise from entering the motor. There is no need to provide a plate, or such a shield can be simplified.

  According to a second aspect of the present invention, in the steering apparatus according to the first aspect, the stator coil includes a plurality of teeth portions arranged radially and windings wound around the teeth portions. The windings are arranged in the order of U phase, V phase and W phase.

  According to the first aspect of the present invention, since disturbance due to noise with respect to the motor rotation signal is reduced, there is no fluctuation in the output of the motor, and good steering feeling can be maintained. In addition, according to the present invention, since the shield and the like can be simplified, the manufacturing cost can be reduced and the steering device can be downsized.

  According to invention of Claim 2, an electric motor can be comprised with a three-phase alternating current motor. Therefore, according to the present invention, the power consumption can be reduced and the electric efficiency can be increased, so that a small electric motor can be used, and the steering device can be miniaturized. .

  Hereinafter, details of a steering apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the drawings to be referred to, FIG. 1 is a schematic diagram showing a steering apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 4 is a sectional view of a brushless motor constituting the steering device of FIG. 1, FIG. 5A is a conceptual diagram of a resolver constituting the steering device of FIG. 1, and FIG. FIG. 6A is a waveform diagram showing the excitation voltage applied to the excitation side coil of the resolver and the sin wave output voltage and the cos wave output voltage induced in the output side coil shown in FIG. It is a block diagram of an electric motor drive control means.

  As shown in FIG. 1, the steering device M is disposed in a steering system S from the steering wheel 1 to the steering wheels SW and SW, and reduces the burden of the steering force applied to the steering system S by the driver. . Here, before describing the steering device M, the steering system S will be described first.

  As shown in FIG. 1, the steering system S is connected to a handle 1, a steering shaft 2 a disposed so as to be integrated with the handle 1, and the steering shaft 2 a via universal joints 2 c and 2 d. The pinion shaft 5a, the rack shaft 5c connected to the pinion shaft 5a and the rack and pinion mechanism 5, and both ends of the rack shaft 5c are connected to each other via ball joints BJ and BJ, and left and right steering Tie rods TR and TR connected to the wheels SW and SW, respectively.

  In this steering system S, when the driver turns the steering wheel 1 and a steering force is applied (steering input), as is apparent when referring to FIG. A pinion shaft 5a rotatably supported by B2 rotates around the axis. The rotational movement of the pinion shaft 5a is caused by the rack and pinion mechanism 5, that is, the pinion gear 5b attached to the tip of the pinion shaft 5a, and the rack gear 5d formed on the peripheral surface of the rack shaft 5c so as to mesh with this. Thus, it is converted into a reciprocating motion in the extending direction of the rack shaft 5c. By such reciprocation of the rack shaft 5c, the steered wheels SW and SW are steered via the ball joints BJ and BJ and the tie rods TR and TR shown in FIG.

  Next, the steering device M according to the present invention will be described. As shown in FIG. 1, the steering device M is a steering input detection unit TS that detects a steering input applied by the driver to the steering system S, and an electric motor that applies an auxiliary torque (auxiliary steering force) to the steering system S. The brushless motor 3, the resolver 7 for detecting the rotational state of the brushless motor 3, the vehicle speed sensor VS for detecting the vehicle speed of a vehicle (not shown) on which the steering device M is mounted, the steering input detecting means TS, the resolver 7 And motor drive control means 8 for controlling the rotation operation of the brushless motor 3 based on a signal output from the vehicle speed sensor VS. The brushless motor 3 corresponds to an “electric motor” in the claims, and the resolver 7 is used together with resolver digital conversion means (hereinafter referred to as RD conversion means 21 (see FIG. 6)) described later. This constitutes the “rotation detection means”.

  In the present embodiment, a steering torque sensor TS1 is used as the steering input detection means TS as shown in FIG. The steering torque sensor TS1 is disposed around the pinion shaft 5a, and torque received by the pinion shaft 5a when the pinion shaft 5a rotates around the shaft in response to a steering input applied to the steering system S by the driver. Is detected. And the detection signal is output toward the electric motor drive control means 8 mentioned later. Examples of such a steering torque sensor TS1 include a magnetostrictive torque sensor.

  The brushless motor 3 generates auxiliary torque that assists the steering torque manually applied to the steering system S by the driver, and this auxiliary torque causes the torque limiter TL and the speed reduction mechanism 4 to move as shown in FIG. Via the pinion shaft 5a. Here, the torque limiter TL, the speed reduction mechanism 4 and the brushless motor 3 will be described in this order.

  The torque limiter TL cooperates with the inner member TL2 by contacting the inner member TL2 fixed by serration to one end side of the output shaft 31 that outputs the rotation of the brushless motor 3 and the outer peripheral surface of the inner member TL2. An outer member TL1 that constitutes a conical clutch and is fixed by serration to one end of a worm shaft that constitutes a speed reduction mechanism 4 to be described below, and a disc spring TL3 that urges the inner member TL2 toward the outer member TL1. I have. When the rotation of the output shaft 31 of the brushless motor 3 is transmitted to the worm shaft 43 of the speed reduction mechanism 4, the torque limiter TL is torque-limiter TL by a conical clutch composed of an inner member TL2 and an outer member TL1. When a large torque exceeding a predetermined value is applied to the inner member TL2, the inner member TL2 and the outer member TL1 slip each other. And by making it slip in this way, this torque limiter TL can restrict | limit the auxiliary | assistant torque from the brushless motor 3, and can cut an overtorque.

  The speed reduction mechanism 4 boosts and transmits the auxiliary torque generated by the brushless motor 3 to the pinion shaft 5a, and has a worm shaft 43 to which the outer member TL1 is attached at one end, and the middle of the worm shaft 43. And a resin worm wheel 42 that is engaged with the worm 41 and is mounted around the pinion shaft 5a so as to be disposed in a plane orthogonal to the pinion shaft 5a. Has been.

  The brushless motor 3 includes an output shaft 31 and a main body 32 that rotates the output shaft 31, and these are disposed in a motor housing 62. The main body 32 includes a rotor 32 a fixed to the output shaft 31 and a stator coil 32 b fixed so as to follow the inner peripheral surface of the motor housing 62.

  As shown in FIG. 4, the rotor 32a is a rotating body including eight (eight poles) permanent magnets in the circumferential direction, and is arranged so that N poles and S poles are alternately arranged along the circumferential direction. Has been.

  The stator coil 32b includes nine tooth members 32d extending radially from the outer peripheral surface of the cylindrical member 32c arranged so as to surround the periphery of the rotor 32a, and windings 32e wound around the respective tooth members 32d. An electromagnet configured. The stator coils 32b are composed of three sets of three phases each including a U phase, a V phase, and a W phase. The U phase, the V phase, and the W phase are arranged around the rotor 32a in this order. A winding 32e is wound around the wire.

  As is apparent from FIG. 3 again, the resolver 7 is a sensor that detects the rotation angle, the rotation direction, and the angular velocity of the rotor 32 a attached to the output shaft 31 of the brushless motor 3, and the other end of the output shaft 31. It arrange | positions at the side, ie, the other side of the said torque limiter TL. The resolver 7 is disposed so as to surround the rotor 71 fixed to the other end of the output shaft 31 of the brushless motor 3, and surrounds the periphery of the rotor 71, and is attached to the motor housing 62 via a mounting plate 73. The coil 72 is fixed.

  The resolver 7 is a salient pole PP in which the rotor 71 is composed of four convex portions projecting radially from the output shaft 31 of the brushless motor 3 at equal intervals, as is apparent when referring also to FIG. have. That is, the number of poles of the rotor 71 is set to one more than the number of sets of the stator coils 32b.

  The coil 72 includes an excitation side coil 72a, a first output side coil 72b, and a second output side coil 72c. In such a resolver 7, every time the brushless motor 3 makes one rotation, an excitation voltage whose voltage amplitude is a sin wave as shown in FIG. 5B is applied to the excitation side coil 72 a. In each of the first and second output side coils 72b and 72c, corresponding to the rotation angle θ of the rotor 71, a cosine wave output voltage and a sine wave output, which are envelopes of voltage amplitude as shown in FIG. A voltage is induced. The cos wave output voltage and the sine wave output voltage are detected by RD conversion means 21 (see FIG. 6) described later. The first and second output side coils 72b and 72c correspond to “coils” in the claims.

  The vehicle speed sensor VS detects the vehicle speed as the number of pulses per unit time, and outputs an analog electric signal corresponding to the detected number of pulses as a vehicle speed signal to an electric motor drive control means 8 described below. Yes. The vehicle speed sensor VS may be a dedicated sensor for the steering device M or a vehicle speed sensor for another system.

  The electric motor drive control means 8 controls the brushless motor 3 by vector control described in a two-phase rotating magnetic flux coordinate system (dq coordinate system). That is, the steering torque applied to the steering system S by the driver is detected by the steering torque sensor TS1, and the brushless motor 3 is vector-controlled so that auxiliary torque (auxiliary steering force) corresponding to the detected steering torque is obtained. (See FIG. 1).

  As shown in FIG. 6, the motor drive control means 8 includes a target current detection means 20, an RD conversion means 21, motor current detection means 22a and 22b, adders 24a, 24b, 27a and 27b, three-phase- It comprises a dq conversion means 23, PI control means 25a, 25b, a non-interacting control means 26, a dq-3 phase conversion means 28, and an electric motor drive means 29.

  The target current detecting means 20 is a steering torque (steering input) detection signal output from the steering torque sensor TS1, and an electric motor rotation signal (of the output shaft 31) indicating the rotation state of the brushless motor 3 output from the RD conversion means 21 described later. Angular velocity ω), the vehicle speed signal output from the vehicle speed sensor VS, and the q-axis target current and d-axis target of the brushless motor 3 from a predetermined function preset in the target current detection means 20 based on these signals. It is comprised so that an electric current may be calculated.

  The RD conversion unit 21 calculates a parameter related to the rotation state of the brushless motor 3 such as the rotation angle θ and the angular velocity ω of the brushless motor 3 based on the cosine wave output voltage and the sin wave output voltage output from the resolver 7. Circuit elements. The calculated detection signal of the rotation angle θ and the angular velocity ω of the brushless motor 3 corresponds to the “motor rotation signal” in the claims.

  The motor current detection means 22 a and 22 b are for detecting the magnitude and direction of each phase current in the stator coil 32 b of the brushless motor 3. In the present embodiment, the motor current detection means 22a and 22b detect the U-phase current Iu and the W-layer current Iw of the stator coil 32b. These electric motor current detection means 22a, 22b can be constituted by, for example, a current transformer provided in each phase winding of the brushless motor 3.

  The three-phase-dq conversion means 23 performs dq conversion based on the phase current of the brushless motor 3 detected by the motor current detection means 22a and 22b and the rotation angle θ of the brushless motor 3 calculated by the RD conversion means 21. The d-axis current Id and the q-axis current Iq of the brushless motor 3 at that time are calculated.

  The adders 24a and 24b receive the d-axis current Id and the q-axis current Iq output from the three-phase-dq conversion unit 23 via the attenuation units 30a and 30b, and the q-axis target output from the target current detection unit 20. Deviations between the current and the d-axis target current and the received d-axis current Id and q-axis current Iq are calculated, respectively. The adders 24a and 24b output the calculated current deviation to PI control means 25a and 25b described below. The attenuating means 30 removes high-frequency noise from the outside mixed in the feedback loop of the d-axis current Id and the q-axis current Iq.

  The PI control means 25a and 25b perform P (Proportional) control processing and I (Integral) control processing on the current deviation output from the adders 24a and 24b, thereby performing d-axis and q-axis control. Each command voltage V′d, V′q is output.

  The non-interference control means 26 cooperates with the adders 27a and 27b connected thereto, and when there is mutual interference between the plurality of control inputs and the plurality of control amounts, the influence of one control input is exerted. It works to eliminate mutual interference so as to reach only one control amount. In the present embodiment, the non-interacting control unit 26 feeds back the angular velocity ω signal output from the RD conversion unit 21 and the d-axis current Id and the q-axis current Iq output from the three-phase-dq conversion unit 23. It is configured to make the loop small (fasten the feedback loop response).

  The dq-3 phase conversion means 28 performs dq reverse conversion on the command voltages Vd, Vq output from the PI control means 25a, 25b via the adders 27a, 27b, thereby providing the U phase of the brushless motor 3, The voltage is converted into respective command voltages V′u, V′v, V′w for the V phase and the W phase. The command voltages V'u, V'v, and V'w are converted into PWM duty signals by a PWM (Pulse Width Modulation) conversion block (not shown).

  The motor driving means 29 is connected to each winding of the brushless motor 3 in accordance with the PWM duty signal by passing through a pre-drive circuit and an FET bridge (both not shown) provided in the motor driving means 29. Is configured to supply.

Next, the operation of the steering device M of the present embodiment will be described with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 7 is a waveform diagram of a signal output from the resolver constituting the steering device of FIG.
First, as shown in FIG. 1, when an ignition switch Ig (not shown) on which the steering device M is mounted is turned on, power is supplied from the battery 9 or the generator G mounted on the vehicle to the steering device M. Then, the steering device M is activated. On the other hand, when the driver turns the steering wheel 1 to apply steering torque to the steering system, the steering torque is transmitted to the steering shaft 2a, the universal joints 2c and 2d, and the pinion shaft 5a. The rotational motion transmitted to the pinion shaft 5a is converted by the rack and pinion mechanism 5 into a reciprocating motion in the extending direction of the rack shaft 5c. The steered wheels SW and SW are steered by the reciprocating motion of the rack shaft 5c.

  When the steered wheels SW and SW are steered in this way, as shown in FIG. 6, the steering torque sensor TS1 outputs a detection signal of steering torque (steering input) toward the target current detecting means 20. The vehicle speed sensor VS outputs a vehicle speed signal toward the target current detection means 20. On the other hand, the rotation detection means composed of the resolver 7 and the RD conversion means 21 is an electric motor that indicates the rotation state of the brushless motor 3 such as the rotation angle θ and the angular velocity ω of the output shaft 31 (see FIG. 3) of the brushless motor 3. Output rotation signal. The RD conversion unit 21 outputs a detection signal of the angular velocity ω toward the target current detection unit 20. Next, the target current detection means 20 calculates the q-axis target current and the d-axis target current of the brushless motor 3 based on these received signals.

  On the other hand, the three-phase-dq conversion means 23 rotates the output shaft 31 of the brushless motor 3 calculated by the RD conversion means 21 or the phase currents Iu, Iw of the brushless motor 3 detected by the motor current detection means 22a, 22b. Dq conversion is performed based on the angle θ, and the d-axis current Id and the q-axis current Iq of the brushless motor 3 at that time are calculated.

  The adders 24a and 24b that receive the d-axis current Id and the q-axis current Iq receive the q-axis target current and the d-axis target current output from the target current detection unit 20, and the received d-axis current Id and q-axis. The deviation from the current Iq is calculated, and the calculated current deviation is output to the PI control means 25a and 25b.

  The PI control units 25a and 25b that have received such current deviations output respective command voltages V′d and V′q for the d-axis and the q-axis by performing PI control processing. These command voltages V′d and V′q are converted into a PWM duty signal by passing through a dq-3 phase conversion means 28 and a PWM conversion block (not shown). A pre-drive circuit and an FET bridge (both not shown) provided in the electric motor drive unit 29 energize each winding of the brushless motor 3 in accordance with a PWM duty signal. As a result, the brushless motor 3 is vector-controlled according to the rotation state of the brushless motor 3 to generate the auxiliary torque described above. The auxiliary torque is transmitted to the pinion shaft 5a through the output shaft 31, the torque limiter TL, and the speed reduction mechanism 4 as shown in FIG. Due to the auxiliary torque transmitted to the pinion shaft 5a, the burden of the steering force on the driver's handle 1 is reduced.

  In this steering device M, auxiliary torque is generated according to the rotational state of the brushless motor 3, so that, for example, when the driver slowly turns the steering wheel, for example, during high-speed driving of an automobile, or a steep course Regardless of when the steering wheel is quickly turned after being forced to change, the steering feeling of the driver is maintained well.

  On the other hand, in this steering device M, as shown in FIG. 4, the stator coil 32b of the brushless motor 3 has nine poles and includes three sets of U phase, V phase, and W phase, and As shown in FIG. 5, the rotor 71 of the resolver 7 includes four salient poles PP. That is, the number of poles of the rotor 71 of the resolver 7 is set to one more than the number of sets of the stator coils 32b. Therefore, in this steering device M, as shown in FIG. 7, while the brushless motor 3 makes one rotation, the fourth-order electric motor rotation signal composed of the sine wave output voltage and the cosine wave output voltage is transmitted to the brushless motor 3. Noise enters a position of 40 ° × n (n is an integer of 1 to 9).

  At this time, the position where the sin wave output voltage becomes zero and the position where the noise enters coincide with the rotation angle (40 °) which is the first position where the noise is generated while the brushless motor 3 rotates once. , The rotation angle indicated by a common multiple with the rotation angle (90 °) that is the position where the first cycle of the sin wave output voltage is completed. That is, the rotation angle indicated by this common multiple during one rotation of the brushless motor 3 is only 360 ° (0 °). Therefore, in this steering device M, disturbance due to noise with respect to the motor rotation signal is reduced. As a result, according to the steering device M, fluctuations in the output (torque) of the brushless motor 3 due to the noise that has entered can be reduced, so that a good steering feeling can be maintained.

As mentioned above, this invention is implemented in various forms, without being limited to the said embodiment.
In the present embodiment, the steering device M in which the number of poles of the winding 32e of the brushless motor 3 is nine and the number of poles of the rotor 71 of the resolver 7 is four is exemplified. It is not limited to the number of poles. In other words, in the steering device of the present invention, the number of poles of the rotor 71 of the resolver 7 only needs to be set to one more than the number of sets of the stator coils 32b. For example, as shown in Table 1 below, the brushless The number of sets of windings 32e determined by the number of poles of the windings 32e of the motor 3 and the number of phases of the brushless motor 3 (here, three phases) is appropriately changed, and the resolver 7 rotates according to the number of sets. The number of poles of the child 71 may be changed. In Table 1, the rotation angle at which the noise is generated during one rotation of the brushless motor 3 and the rotation angle at which the sin wave output voltage becomes zero, that is, the noise that has entered the motor rotation The rotation angle affecting the signal is described as “rotation angle affected by noise”. Table 1 also shows the resolver used in the conventional steering device.

  As can be seen from Table 1, in such a steering device, the influence of noise entering the motor rotation signal is reduced as compared with the conventional steering device, so that the fluctuation (output) of the brushless motor is less. Good steering feeling is maintained.

  In the present embodiment, the rotor 71 of the resolver 7 has four salient poles PP that protrude radially from the output shaft 31 of the brushless motor 3 at regular intervals. For example, as shown in FIG. 8A and FIG. 8B, these salient poles PP are equally spaced from the output shaft 31 of the brushless motor 3 according to the number of salient poles PP. Alternatively, a rotor 71 that protrudes radially may be used.

  In the present embodiment, the brushless motor 3 is vector-controlled by the electric motor drive control means 8, but the present invention is not limited to this. For example, a rectangular wave current is generated between the phases of the brushless motor 3. It may be configured to energize, or may be configured to energize a pseudo sine wave current in which rectangular waves are combined between phases.

It is the schematic which shows the steering device which concerns on embodiment of this invention. It is sectional drawing in the AA of FIG. It is sectional drawing in the BB line of FIG. It is sectional drawing of the brushless motor which comprises the steering apparatus of FIG. (A) is a conceptual diagram of the resolver constituting the steering device of FIG. 1, and (b) is an excitation voltage applied to the excitation side coil of the resolver shown in (a) and a sine wave output induced by the output side coil. It is a wave form diagram which shows a voltage and a cosine wave output voltage. It is a block diagram of the electric motor drive control means which comprises the steering apparatus of FIG. It is a wave form diagram of the signal output from the resolver which comprises the steering apparatus of FIG. (A) And (b) is a conceptual diagram of the rotor of the resolver which comprises the steering apparatus which concerns on other embodiment of this invention. It is a wave form diagram of the signal output from the resolver which comprises the conventional steering apparatus.

Explanation of symbols

3 Brushless motor (electric motor)
7 Resolver (Rotation detection means)
8 Motor drive control means (control means)
21 RD conversion means (rotation detection means)
32b Stator coil 71 Rotor 72b First output side coil (coil)
72c Second output side coil (coil)
M Steering device PP Salient pole S Steering system TS Steering input detection means TS1 Steering torque sensor

Claims (2)

An electric motor for applying torque to the steering system;
Steering input detection means for detecting a steering input to the steering system by the driver and outputting a detection signal thereof;
Rotation detecting means for detecting the rotation state of the electric motor and outputting the detected electric motor rotation signal;
A steering apparatus comprising: a control unit that controls a rotation operation of the electric motor based on the detection signal from the steering input detection unit and the electric motor rotation signal from the rotation detection unit;
The electric motor includes a plurality of magnets and a plurality of stator coils each including three phases.
The rotation detection means includes a rotor having a plurality of poles and rotating in synchronization with the electric motor, and a coil for inducing an AC output voltage according to the rotation angle of the rotor,
The steering device according to claim 1, wherein the number of poles of the rotor is one more than the number of sets of the stator coils.   The stator coil is composed of a plurality of teeth portions arranged radially and windings wound around the teeth portions, and the windings are arranged in the order of U phase, V phase, and W phase. The steering apparatus according to claim 1, wherein the steering apparatus is provided.

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