JP2011257316A - Torque sensor for power steering and motor-driven power steering device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque sensor for power steering that increases values of an operation signal and a signal generated based thereupon even when small steering wheel operation is performed.SOLUTION: A signal generation circuit 313 includes a contact section comprising contacts X1-X2, a contact section comprising contacts X2-X3, and a contact section comprising contacts X3-X1, the contact sections being formed by Δ connection. In the contact section comprising contacts X1-X2, a composite coil LB is wired and induction voltages generated by Lb1-Lb3 of the composite coil LB respectively are put together to generate a voltage Vb corresponding to a (b) phase. In the contact section comprising contacts X2-X3, a composite coil LA is wired and a voltage Va corresponding to an (a) phase is generated. In the contact section comprising contacts X3-X1, a composite coil LC is wired and a voltage Vc corresponding to a (c) phase is generated.

Description

  The present invention relates to a power steering torque sensor and an electric power steering apparatus including the same, and is used particularly when optimizing a signal value of a torque sensor.

  Electric power steering device EPS (Electric Power-Steering System) mounted on a vehicle includes a power steering torque sensor (hereinafter simply referred to as a torque sensor) that detects operation torque, and assist torque according to the torque sensor signal. Is configured from an electric power steering motor unit (hereinafter referred to as a motor unit) that appropriately adjusts and an output torque obtained by adding an assist torque to an operation torque. In such an electric power steering apparatus, when the operator operates the steering wheel, torque is applied to the steering shaft, and the torque sensor detects the state of this torque. Thereafter, the electric power steering apparatus drives the electric motor according to the signal from the torque sensor, and generates assist torque according to the pilot's intention to operate.

  In an electric power steering device, a magnetostrictive torque sensor that detects a change in magnetic permeability from a magnetostrictive material formed on a steering shaft, a hall element torque sensor that detects torsion of a torsion bar using a hall element, and a torsion bar torsion In addition, various types of sensors such as an inductance type torque sensor that changes the passage cross section of the magnetic flux according to the above, and a resolver type torque sensor have been put into practical use.

  However, these torque sensors detect information corresponding to the torsion angle of the shaft and detect the operation torque at the time of operating the steering wheel. Therefore, a torsion bar having low rigidity is used to accurately detect the torsion angle of the shaft. It will be necessary. For this reason, the mechanism around the torsion bar is complicated in the electric power steering apparatus, and there is a problem that the number of parts increases, the apparatus becomes larger, and the cost increases.

  As a technique for avoiding such a problem, Japanese Patent Application No. 2010-141411 (Patent Document 1) introduces a technique in which a technique related to a generator is applied to a torque sensor (hereinafter referred to as a generator-type torque sensor). Yes. The generator-type torque sensor includes a rotor in which permanent magnets (magnetic flux generators in claims) are arranged in the circumferential direction, and a rotor-side circuit (signal generation circuit in claims) that forms a coil. And a stator that arranges coils of the rotor side circuit at a plurality of locations. Among these, the stator is attached to the inside of the electric power steering apparatus, and the rotor performs relative motion with respect to the plurality of coils formed on the stator when a steering operation is performed.

  When a steering wheel operation is performed, the generator torque sensor generates regenerative electric power according to the rotation of the rotor, and thereby outputs an operation signal indicating the steering wheel operation from the signal generation circuit. A plurality of operation signals Sg1 and Sg2 are output from the generator torque sensor. Each of these operation signals has an amplitude of the signal corresponding to the operation torque indicating the strength of the handle operation, and the operation signals Sg1 and Sg2 according to the operation direction when the handle is rotated. The generation timing of is switched.

  The operation signals Sg1 and Sg2 output from the generator torque sensor are input to the signal processing circuit, and information regarding the operation torque or the operation direction is extracted by the signal processing circuit. As shown in FIG. 19, the signal processing circuit 400 includes a torque signal generation circuit 410 and a direction signal generation circuit 420. Among these, the torque signal generation circuit 410 includes a filter circuit 411, an amplifier circuit 412, a rectifier circuit 413, and a smoothing circuit 414. The torque signal generation circuit 410 removes high-frequency noise from the operation signal Sg1 input by the filter circuit 411 (see FIG. 20a), amplifies the signal value by the amplifier circuit 412 (see FIG. 20b), and the rectifier circuit 413. The signal amplified in step (b) is subjected to full-wave rectification (see FIG. 20c), and thereafter, the smoothing circuit 414 outputs a signal value Vt that varies in accordance with the amplitude value to a subsequent circuit (FIG. 20d). This signal value Vt is a torque signal St representing the operation torque.

  On the other hand, the direction signal generation circuit 420 includes amplification circuits 415 and 422, a filter circuit 421, and a flip-flop circuit 423. In the direction signal generation circuit 420, both the operation signal Sg1 and the operation signal Sg2 are processed as illustrated. Of these, the operation signal Sg1 passes through the filter circuit 411, is then formed into a rectangular wave by the amplifier circuit 415, and is input to the signal input terminal D of the flip-flop circuit 423. The operation signal Sg2 passes through the filter circuit 421, is then formed into a rectangular wave by the amplifier circuit 422, and is input to the clock input terminal CLK of the flip-flop circuit 423. The flip-flop circuit 423 outputs a direction signal Sr indicating the operation direction of the handle based on the input timing of the rectangular wave input to the signal input terminal D and the rectangular wave input to the clock input terminal CLK.

  The torque signal St and the direction signal Sr output from the signal processing circuit 400 are sent to the motor unit of the power steering apparatus and processed by a control circuit that controls the motor unit. Upon receiving these signals St and Sr, the control circuit for the motor unit recognizes the direction in which the assist torque is applied and adjusts the magnitude of the assist torque based on the signals.

Japanese Patent Application No. 2010-121411

  Generally, the angular velocity of the drive shaft during steering operation is assumed to be 0.2π to 2π (rad / sec). Therefore, in the technique according to Patent Document 1, for use as a torque sensor for power steering, the regenerative power becomes small during operation at such a low angular velocity, and the amplitude of the operation signal and the torque signal based on this become extremely small. . In such a case, if the control circuit for controlling the motor unit does not have sufficient resolution with respect to the input signal, it is difficult to recognize the torque signal, and there arises a problem that the assist torque according to the steering wheel operation cannot be commanded.

  Further, in the direction signal generation circuit 420 described with reference to FIG. 19, if both of the input operation signals Sg1 and Sg2 are larger than a predetermined power supply voltage, the amplification circuits 415 and 422 cannot form a rectangular wave. As described above, if the rectangular wave is not formed correctly, the flip-flop circuit 423 cannot correctly recognize the input timing of the operation signal Sg1 and the operation signal Sg2, so that there is a problem that an error occurs in the rotation signal indicating the operation direction. Arise.

  Further, as shown in FIG. 19, when a torque signal is generated by the smoothing circuit 414, in order to keep the torque signal at a stable value, a smoothing capacitor and peripheral resistance elements are appropriately selected, and an RC circuit constituted by this. It is necessary to increase the time constant τ. However, in order to set the time constant τ of the RC circuit large, it is necessary to increase the electric capacity of the smoothing capacitor and the resistance value of the resistance element, leading to an increase in circuit element size and associated cost. Problems arise.

  In view of the above problems, the present invention provides a power steering torque sensor that increases the value of an operation signal and a signal generated based on the operation signal even when a small number of steering operations are performed, and an electric type using the same An object is to provide a power steering device.

In order to solve the above problems, the present invention has the following configuration of a power steering torque sensor. That is, a rotor that rotates in response to a handle operation, a signal generation circuit that includes a composite coil composed of at least two coils, and a relative positional variation with respect to the coil occurs in response to the handle operation. A magnetic flux generation unit, and a stator that constitutes a generator by being combined with the rotor, the signal generation circuit, and the magnetic flux generation unit,
The composite coil is wired in a connection section that generates a predetermined phase voltage in the signal generation circuit, and generates an operation signal by synthesizing induced electromotive forces generated in the coils in the connection section.

  Preferably, the signal generation circuit includes a plurality of the connection sections, the composite coil is provided in each of the connection sections, and generates a plurality of the operation signals.

  Preferably, the signal generation circuit is provided in the stator.

  Preferably, in the composite coil, at least two coils constituting the composite coil are connected in parallel.

  Preferably, in the composite coil, all the coils constituting the composite coil are connected in parallel.

  Preferably, all the coils formed in the signal generation circuit have the same winding direction.

  Preferably, among the coils formed in the signal generation circuit, the coils having the same connection section are arranged at equal intervals in the circumferential direction of the rotor or the stator.

  Preferably, all the coils formed in the signal generation circuit are arranged at equal intervals in the circumferential direction of the rotor or the stator.

  Preferably, the magnetic flux generator is configured to form at least four poles alternately arranged in a circumferential direction of the rotor or the stator, and the connection section of the coils formed in the signal generation circuit includes The at least two or more coils that are the same have a common polarity approaching at substantially the same timing.

  Preferably, the magnetic flux generator is configured to form at least four poles alternately arranged in a circumferential direction of the rotor or the stator, and the connection section of the coils formed in the signal generation circuit includes It is assumed that the common polarity approaches all the same coils at substantially the same timing.

  Preferably, the common polarity approaches each of the coils constituting one of the connection sections, and the common polarity approaches each of the coils constituting the other connection sections excluding the one connection section. The timing is different.

  Preferably, an angular velocity amplification mechanism that increases the angular velocity of the rotor more than the angular velocity of the steering shaft is provided.

In the present invention, the following power steering torque sensor may be used. That is, a rotor that rotates in response to a handle operation, a signal generation circuit that forms a coil and generates an operation signal based on an induced electromotive force generated in the coil, and a relative position change with respect to the coil A magnetic flux generating section generated according to the above, and a stator that constitutes a generator by being combined with the rotor, the signal generating circuit, and the magnetic flux generating section,
It is assumed that the magnetic flux generator has at least four or more polarities arranged alternately in the circumferential direction of the rotor or the stator.

  In the present invention, the following power steering torque sensor may be used. That is, a rotor that rotates in response to a steering wheel operation, an angular velocity amplification mechanism that increases the angular velocity of the rotor over the angular velocity of the steering shaft, and an operation signal based on an induced electromotive force that is generated by the coil. A generator by combining a signal generation circuit to generate, a magnetic flux generation unit in which a relative position variation with respect to the coil is generated in response to the handle operation, and the rotor, the signal generation circuit, and the magnetic flux generation unit; It shall be provided with the comprised stator.

  Furthermore, an electric power steering apparatus including any of the above-described power steering torque sensors may be used.

  According to the torque sensor for power steering according to the present invention, by providing a composite coil, the frequency of the operation signal output from the signal generation circuit is improved, thereby increasing the amount of change in magnetic flux and the output value of the operation signal. Can be increased.

  Also, increasing the number of poles of the magnetic poles and alternately arranging the polarities of the magnetic poles also improves the frequency of the operation signal output from the signal generation circuit, thereby increasing the amount of change in magnetic flux and the operation signal. The output value of can be increased.

  Also, by providing a mechanism for increasing the rotational speed of the rotor, it is possible to increase the amount of change in magnetic flux at the coil end and increase the output value of the operation signal.

  Furthermore, according to the power steering torque sensor of the present invention, the amplitude value of each of the operation signals is sufficiently large, so that the rectangular wave shape used as the input signal to the flip-flop circuit is suitably maintained, and the flip-flop Misrecognition of signals in the circuit is eliminated. That is, the reliability of the direction signal is improved.

  In addition, since a high-frequency operation signal is input to the signal processing circuit 400, the time constant of the RC circuit can be set low for a circuit that smoothes the operation signal and generates a torque signal. It is possible to reduce the physique of the electric element to be used and to reduce the cost. That is, the electric capacity of the smoothing circuit 414 in FIG. 19 can be reduced.

The figure which shows the structure of an electrically driven power steering apparatus. The figure which shows the power transmission mechanism of an EPS motor. The figure which shows the structure of the torque sensor which concerns on embodiment. The figure which shows the cross-section of the torque sensor which concerns on embodiment. The figure which shows the torque sensor and signal processing circuit which concern on 1st Embodiment. The figure which shows the signal generation circuit which concerns on 1st Embodiment. The figure which shows the torque sensor and signal processing circuit which concern on 2nd Embodiment. The figure which shows the signal generation circuit which concerns on 2nd Embodiment. 1 is a diagram illustrating a structure of a torque sensor according to a first embodiment. The figure which compares the operation signal which concerns on a prior art example, and the operation signal which concerns on Example 1. FIG. FIG. 6 is a diagram illustrating a structure of a torque sensor according to a second embodiment. The figure which compares the operation signal which concerns on a prior art example, and the operation signal which concerns on Example 2. FIG. FIG. 6 is a diagram illustrating a structure of a torque sensor according to a second embodiment. The figure which compares the operation signal which concerns on a prior art example, and the operation signal which concerns on Example 2. FIG. FIG. 6 is a diagram illustrating a structure of a torque sensor according to a third embodiment. FIG. 6 is a diagram illustrating a configuration of an angular velocity amplification mechanism according to a fourth embodiment. FIG. 10 is a diagram for explaining the operation of the rotor when the angular velocity amplification mechanism according to the fourth embodiment is used. FIG. 6 is a diagram for explaining an operation signal when an angular velocity amplification mechanism according to a fourth embodiment is used. The functional block diagram which shows a signal processing circuit. The figure explaining the process by which a torque signal is produced | generated. The figure which shows the structure of the torque sensor which concerns on a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the electric power steering device 200 is a column type electric power steering device, and includes a steering shaft 211, a shaft case 220, a torque sensor accommodating portion 300, a signal terminal 300 a, and a gear box 250. Part 200 and a motor unit 100 fixed to the main body part. Hereinafter, the axial center of the steering shaft 211 is referred to as the axial direction, the side on which the gear box 250 in the axial direction is disposed is referred to as a rear side DR, and the opposite side of the rear side DR is referred to as a front side DF. Note that a pinion gear box PGW is connected to the front side DF via a transmission shaft CSH, and a handle device HDM is connected to the rear side DR.

  The handle device HDM (not shown) includes a handle that is operated by a driver, and rotates the steering shaft 211 of the electric power steering device when the handle is operated. Some of the handle devices HMD include an airbag device that protects the operator in the event of a collision or an assist device that generates assist torque.

  The steering shaft 211 forms a cylindrical rod body and is accommodated in the shaft case 220. Since the mechanism around the steering shaft does not have a torsion bar inside, the mechanism is very simple. The steering shaft 211 has a male screw 211a and a spline 211b on the front side DF, and a spline 212 on the rear side DR. The steering shaft 211 has a steering device HDM connected to the rear side DR and a pinion gear box PGW connected to the front side DF, and transmits an operation torque generated by the steering operation to a wheel steering mechanism (not shown).

  The torque sensor housing unit 300 allows the steering shaft 211 to pass therethrough, and a torque sensor (not shown) is disposed around the steering shaft 211. The torque sensor (the power steering torque sensor in the claims) has a wire drawn out and appropriately wired to the signal terminal 300a. The signal terminal 300a is connected to the control circuit 150 of the motor unit 100 via a harness (not shown). When the steering shaft 211 rotates, the torque sensor outputs a torque signal indicating the operation torque and a direction signal indicating the operation direction to the motor unit 100. A torque sensor not shown will be described in detail later.

  As shown in the figure, the gear box 250 is integrally formed with a gear side bracket 252, and the motor unit 100 is fixed using bolts and nuts B / N. The internal structure of the gear box 250 will be described with reference to FIG. FIG. 2 shows a cross-sectional view of the AA cross section in FIG. 1 observed in the direction of the arrow. In this gear box 250, a worm housing portion 251 and a spur gear housing portion 252 are integrally formed.

  The worm housing portion 251 includes an input shaft 253 that rotates in conjunction with the operation of the motor unit 100. The input shaft 253 is formed with a worm gear 253g and is rotatably supported by bearings 254a and 254b.

  The spur gear 252g is formed with teeth of the same module as the worm gear 253g and meshes with the worm gear 253g. The spur gear accommodating portion 252 has a steering shaft 211 attached to the center thereof, and the steering shaft 211 rotates in conjunction with the operation of the spur gear 252g. That is, these parts built in the gear box 250 constitute a reduction gear mechanism for the electric power steering apparatus.

  Returning to FIG. The motor unit 100 includes a motor housing unit 160 incorporating a control motor, a power conversion unit 130 incorporating a drive circuit such as a motor drive transistor (power transistor), and a control for generating a drive signal for the motor drive transistor. The circuit unit 150 is configured. When receiving the torque signal from the torque sensor, the control circuit unit 150 generates and outputs a PWM signal necessary for generating the assist torque. At this time, in the drive circuit, each power transistor is appropriately driven according to the PWM signal, and the electric power applied from the terminal unit 140 is converted into an appropriate waveform. Accordingly, the control motor is appropriately controlled by the drive circuit, and generates an output torque corresponding to the torque signal and the direction signal.

  In the electric power steering apparatus having such a configuration, when a driver operates the handle device HDM, an operation torque is transmitted to the steering shaft 211 in accordance with the handle operation. In response to this, the torque sensor outputs a torque signal and a direction signal corresponding to the steering operation, and requests the motor unit 100 for assist torque. The control circuit unit 150 receives a torque sensor signal and calculates a required torque amount and assist direction of the assist torque. The motor unit 100 transmits the steering shaft via the worm gear 253g and the spur gear 252g. Assist torque is given to 211. That is, the electric power steering device generates assist torque based on a signal from the torque sensor, and reduces the force necessary for the steering operation of the operator.

  FIG. 3 shows the configuration of the torque sensor TS built in the torque sensor housing part 300. The torque sensor TS has a generator 310 as a main component, and specifically includes a rotor 312 and a stator 311. The stator 311 and the rotor 312 are made of laminated silicon steel plates. Among these, the stator 311 is provided with a slot forming portion SL therein, and a coil is wound around the slot forming portion SL. This coil is composed of a resistor and a wire not shown, and forms a part of a signal generation circuit. On the other hand, the illustrated rotor 312 is provided with a permanent magnet (a magnetic flux generator in the claims) on the circumference. That is, the generator shown in the figure is a synchronous generator. However, the meaning of the term “torque sensor” described in the claims is not limited to the form of a brushless generator or a brush generator. The brushless generator can be replaced with an induction generator in addition to the illustrated synchronous generator. Any of these various generators operates so that the relative position between the permanent magnet and the coil varies when a steering operation is performed.

  FIG. 4 shows a sectional structure of the torque sensor housing 300 and the torque sensor. As shown in the figure, the torque sensor housing part 300 includes a housing 301 and houses the torque sensor TS on the inner peripheral side of the housing 301.

  The housing 301 is fitted with the outer peripheral surface of the stator 311, and is disposed at an appropriate position by the gear box 250 and the flange portion of the shaft case 220. The gear box 250, the shaft case 220, and the housing 301 are integrally fixed by bolts and nuts B / N provided at a plurality of locations. Further, a through hole is formed in the radial direction in the flange on the housing side, and the signal lines L1 and L2 are inserted therethrough.

  The steering shaft 211 is pivotally supported by a bearing or the like (not shown) and is disposed substantially coaxially with respect to the central axis of the stator 311. Since the rotor 312 is fixed to the steering shaft 211, the inside of the stator 312 is rotated according to the steering wheel operation of the operator.

  As described above, according to the torque sensor according to the present embodiment, the torsion bar and a complicated mechanism for fixing the torsion bar can be eliminated, so that the number of parts, the size of the apparatus, and the cost can be reduced.

Such a torque sensor is not a sensor that directly detects the torsion of the mechanism. Therefore, the torque sensor can be used in an electric power steering device in which an operation mechanism on the steering wheel side and a steering mechanism on the tire side are mechanically independent. . For this reason, according to the electric power steering according to the present embodiment, if a steering shaft in which a mechanism operated by the operator and a steering mechanism on the tire side are mechanically independent is used, a steer-by-wire device is provided. Configuration is possible.
(First embodiment)

  FIG. 5 shows wiring between the torque sensor TS and the signal processing circuit 400 according to the first embodiment. In addition, the figure shows the state observed from the aa cross section shown in FIG. That is, Fx indicates the direction of rotation to the right, and Fy indicates the direction of rotation to the left.

  As illustrated, slot forming portions SLa to SLc are formed in the stator 311 every 120 °, and coils La to Lc around which wire wires are wound are provided corresponding to the slot forming portions. The end of each coil is laid out so as to face the rotor 312, and when the permanent magnet passes, the magnetic flux passing through the inside of the coil varies. In this embodiment, each coil is wound with a coil wire so that a positive voltage is generated when the S pole approaches, and a negative voltage is generated when the N pole approaches. That is, all the coils formed in the signal generation circuit have the same winding direction.

  Each coil is connected in parallel with a resistor corresponding to each coil. In the figure, the wiring between the points a and a, the wiring between the points b and b, and the wiring between the points c and c are not shown. Is wired.

  FIG. 6 shows a signal generation circuit formed by coils, resistors, and wire lines. The signal generation circuit 313 according to the present embodiment employs Δ connection. More specifically, the coils La to Lc are wired in a Δ shape, and similarly, the resistors Ra to Rc are also wired in a Δ shape. Further, the coil side contacts X1 to X3 and the resistance side contacts Y1 to Y3 are connected to each other by wire wires. Among these, in the contact section composed of the contacts X1 to X2, the coil b is wired to generate the voltage Vb corresponding to the b phase. The contact section composed of the contacts X2 to X3 is wired with the coil a and generates a voltage Va corresponding to the a phase, and the contact section composed of the contacts X3 to X1 is wired with the coil c and corresponds to the c phase. A voltage Vc is generated. In this embodiment, the signal generation circuit is Δ-connected. However, the present invention is not limited to this, and a signal generation circuit having a Y-connection can also be used.

  The signal generation circuit 313 generates an induced voltage Va in the coil La when, for example, the S pole or N pole of the rotor (hereinafter sometimes collectively referred to as a magnetic pole) passes through the slot forming portion SLa. Similarly, when the S pole or N pole of the rotor passes through the slot forming portion SLc, an induced voltage Vc is generated by the coil Lc. That is. In the signal generation circuit 313, when the rotor 312 rotates in accordance with the handle operation, the magnetic flux penetrating the coil is changed, thereby generating an operation signal indicating the handle operation. In addition, since this operation signal is generated by the power generation action of the generator composed of the rotor 312 and the stator 311, the power for generating the signal is not necessary.

  As illustrated, the signal generation circuit 313 is provided with signal lines L1 and L2. Among these, the signal line L1 is connected to the wire line between the contacts X1 to Y1, and the signal line L2 is connected to the wire line between the contacts X2 to Y2. In addition, the contact X3 to the contact Y3 are brought into contact with the chassis of the automobile, for example, to coincide with the reference potential of the automobile.

  As described above, by using the signal transmission means connected to the signal generation circuit 313, it is possible to extract the operation signal generated by the torque sensor TS. Note that the signal transmission means (the signal line in the present embodiment) does not necessarily need to be connected to the wire line. For example, if a coil type sensor or the like is provided on the wire of the signal generation circuit, the signal transmission means is connected to the sensor device.

  In the torque sensor TS according to the present embodiment, coils are arranged at three locations, and signal lines are respectively connected to different contacts X1 and X2. Here, when the handle is operated from “Lc → Lb → La (right rotation direction)”, first, the magnetic pole passes through the coil Lc, and the potential of the contact X1 varies. At this time, the operation signal Sg1 is output from the signal line L1 in accordance with the potential fluctuation at the contact X1. Further, since the rotor 312 is rotated to the right, the magnetic pole passes through the coil Lb, and the potential at the contact X2 varies. At this time, the operation signal Sg2 is output from the signal line Sg2 in accordance with the potential fluctuation at the contact X2.

  On the other hand, when the handle is operated from “La → Lb → Lc (counterclockwise direction)”, first, the magnetic pole passes through the coil La, and the potential of the contact X2 varies. At this time, the operation signal Sg2 is output from the signal line L2 in accordance with the potential fluctuation at the contact X2. Further, since the rotor 312 is rotated leftward, the magnetic pole passes through the coil Lb, and the potential at the contact X1 varies. At this time, the operation signal Sg1 is output from the signal line Sg1 in accordance with the potential fluctuation at the contact X1.

  That is, in this embodiment, the signal lines L1 and L2 are connected to different positions, so that the generation timing of the operation signal (the phase difference in the operation signal) generated according to the rotation operation of the rotor is detected. Thereby, the operation direction can be detected.

  In the case of detecting the rotation direction by such a method, if a stator consisting of two coils is used, the rotor 312 will be “first coil → second coil → first coil regardless of the rotation direction”. Each coil is excited in the order of “coil →...”, And the operation direction information cannot be added to the operation signal. For this reason, it is preferable to form a coil having three or more phases in the stator. Further, by combining three or more coils of different phases, it is possible to provide signal lines at two or more locations and secure a ground line to the reference potential.

Returning to FIG. 5 again, the description will be continued. As illustrated, the torque sensor TS is further provided with a signal processing circuit 400. In the signal processing circuit 400, the signal lines L1 and L2 are connected to an input unit, the drive signal Sg1 is input via the signal line L1, and the drive signal Sg2 is input via the signal line L2. The signal processing circuit 400 according to the present embodiment performs signal processing based on the drive signals Sg1 and Sg2, and outputs a torque signal St and a direction signal Sr. The torque signal St is a signal indicating the operation torque at the time of the steering wheel operation, and the direction signal is a signal indicating the operation direction at the steering wheel operation (right rotation direction / left rotation direction).
(Second Embodiment)

  FIG. 7 shows wiring between the torque sensor TS and the signal processing circuit 400 according to the second embodiment. The figure shows a torque sensor TS different from that of the first embodiment, and shows a state observed from the aa cross section shown in FIG. 4 as described above. Further, parts having the same configuration as that of the first torque sensor are denoted by the same reference numerals, and description thereof is omitted.

  As shown in the drawing, the stator 311 is provided with nine slot forming portions every 40 °. Coils La to Lc around which wire wires are wound are provided corresponding to the slot forming portions. Note that the signal processing circuit and the stator signal generation circuit are actually wired appropriately through signal lines, as in the first embodiment.

  FIG. 8 shows a signal generation circuit formed by coils, resistors, and wire lines. In the signal generation circuit 313 according to the second embodiment, a contact section composed of the contacts X1 to X2, a contact section composed of the contacts X2 to X3, and a contact section composed of the contacts X3 to X1 are formed by Δ connection. . Among these, in the contact section composed of the contacts X1 to X2, the composite coil LB is wired, and the induced voltages generated in the respective Lb1 to Lb3 of the composite coil LB are combined to generate a voltage Vb corresponding to the b phase. In the contact section composed of the contacts X2 to X3, the composite coil LA is wired, and the induced voltages generated in the respective La1 to La3 of the composite coil LA are combined to generate a voltage Va corresponding to the a phase. In the contact section composed of the contacts X3 to X1, the composite coil LC is wired, and the induced voltages generated in the respective composite coils LC are synthesized to generate the voltage Vc corresponding to the c phase. In the second embodiment, since all the coils (for example, La1 to La3) in each connection section are connected in parallel, even if any of these coils La1 to La3 is disconnected, the other The operation signal can be generated by the coil.

  FIG. 9A shows a torque sensor TS1 according to the present embodiment. As the torque sensor TS1, the signal generation circuit according to the second embodiment is used, and a synchronous generator is employed. Thus, by using a synchronous generator, the signal generation circuit is wired on the stator side, and it is possible to easily extract an operation signal without using a commutator or the like. .

  In the rotor 312 according to the present embodiment, permanent magnets are arranged at two locations, and the S pole and the N pole are arranged one by one in the circumferential direction. In FIG. 9A, the phase difference between the S pole and the N pole is 180 °.

  In the torque sensor TS1, the coils La1 to La3 constitute a composite coil relating to the a phase, the coils Lb1 to Lb3 constitute a composite coil relating to the b phase, and the coils Lc1 to Lc3 constitute a composite coil relating to the c phase. . As shown in FIG. 10B, the coils constituting these composite coils (meaning “connection section is common”) are arranged every 120 ° (equally spaced) in the circumferential direction of the stator 311. Then, an operation signal having a constant peak value period is generated. Further, in this embodiment, since the respective coils constituting the composite coil are connected in parallel, it is possible to obtain a substantially uniform operation signal regardless of the rotational position of the rotor.

  FIG. 10A shows an operation signal of the torque sensor TS0 shown in FIG. 21 as a comparison target of the operation signal of the torque sensor TS1 according to the present embodiment. In the torque sensor TS0, since only one coil corresponding to each phase is wired, a sine curve (operation signal) appears only for one period with respect to the rotation period T0 of the rotor.

  On the other hand, as shown in FIG. 10 (b), in the torque sensor TS1 according to the present embodiment, three coils corresponding to each phase are wired, so that a sine curve with respect to the rotation period T0 of the rotor. (Operation signal) appears three cycles at a time. As described above, when the frequency related to the operation signal increases, the rate of change of the magnetic flux in each coil increases, so that the amplitude value of the operation signal increases as shown in FIG. The value of the torque signal St can be increased.

  Further, since the amplitude value of each of the operation signals becomes sufficiently large, the rectangular wave shape used as the input signal to the flip-flop circuit is suitably maintained, and erroneous recognition of the signal in the flip-flop circuit is eliminated.

  Further, since the signal processing circuit 400 receives an operation signal having a triple frequency, the time constant of the RC circuit can be set low for a circuit that smoothes the operation signal and generates the torque signal St. Thus, the physique of the electrical element to be used can be reduced and the cost can be reduced. That is, the electric capacity of the smoothing circuit 414 in FIG. 19 can be reduced.

  In the present embodiment, as shown in FIG. 9B, the layout of the magnetic poles may be changed so that the S pole and the N pole are adjacent to each other. In such a case, a distorted waveform is generated as shown in FIG. However, even with such an operation signal, the peak value of the waveform increases, and the signal processing circuit 400 can generate a sufficiently large torque signal.

  FIG. 11A shows a torque sensor TS3 according to the present embodiment. The torque sensor TS3 uses the signal generation circuit according to the first embodiment, and employs a synchronous generator.

  In the rotor 312 according to the present embodiment, permanent magnets are arranged at four locations, and the polarities of the S pole or the N pole are alternately arranged in the circumferential direction.

  Such a torque sensor TS3 greets the S pole and the N pole twice each while the rotor 312 makes one round. That is, in the rotor 312 in which the polarities are alternately arranged, the magnetic flux change rate at the coil tip increases according to the number of poles of the magnetic poles.

  FIG. 12A shows an operation signal of the torque sensor TS0 shown in FIG. 21 as a comparison target of the operation signal of the torque sensor TS3 according to the present embodiment. In the torque sensor TS0, since only one S pole and one N pole are provided on the rotor, a sine curve (operation signal) appears only for one period with respect to the rotation period T0 of the rotor.

  On the other hand, as shown in FIG. 12B, in the torque sensor TS3 according to the present embodiment, two S poles and N poles are alternately arranged, so that the rotation period T0 of the rotor is A sine curve (operation signal) appears every two cycles. As before, when the frequency related to the operation signal increases, the rate of change of the magnetic flux in each coil increases, so the amplitude value of the operation signal increases, and thus the torque signal St output from the signal processing circuit 400 increases. The value can be increased.

  In this embodiment, as shown in FIG. 11B, the layout of the magnetic poles may be changed so that the S pole and the N pole are adjacent to each other. In such a case, a distorted waveform is generated as shown in FIG. However, even with such an operation signal, the peak value of the waveform increases, and the signal processing circuit 400 can generate a sufficiently large torque signal.

  In the case of the torque sensor TS5 as shown in FIG. 13, the output timings of the operation signal Sg1 and the operation signal Sg2 output from the signal generation circuit 313 coincide (see FIGS. 14a and 14b). In the circuit 400, it is difficult to generate a signal related to the operation direction of the handle. However, when the number of coils and magnetic poles corresponds to each other, as shown in FIG. 13B, the waveform pattern of the operation signal when operating the handle in the right direction by making the arrangement pitch of the magnetic poles uneven. A difference appears between the waveform pattern of the operation signal (see FIG. 14d) when the steering wheel is operated to the left (see FIG. 14c). If the signal processing circuit 400 uses a circuit that recognizes the difference between the waveform patterns, it is possible to generate information on the rotation direction from the operation signal.

  FIG. 15A shows a torque sensor TS7 according to the present embodiment. The torque sensor TS7 uses the signal generation circuit according to the second embodiment, and employs a synchronous generator.

  In the rotor 312 according to the present embodiment, permanent magnets are arranged at six locations, and the polarities of the S pole or the N pole are alternately arranged in the circumferential direction. In FIG. 15A, the phase difference between adjacent polarities is 60 °.

  In the torque sensor TS1, the coils La1 to La3 constitute a composite coil relating to the a phase, the coils Lb1 to Lb3 constitute a composite coil relating to the b phase, and the coils Lc1 to Lc3 constitute a composite coil relating to the c phase. .

  In the present embodiment, all of the coils La1 to La3 constituting the composite coil related to the a phase have the common polarity of the S pole or the N pole approaching at substantially the same timing. In addition, for the composite coil related to the b phase, the common polarity of the S pole or the N pole approaches each of Lb1 to Lb3 of the composite coil at approximately the same timing. Further, for the composite coil related to the c phase, the common polarity of the S pole or the N pole approaches each of Lc1 to Lc3 of the composite coil at substantially the same timing. That is, the timing at which the common polarity approaches each of the coils constituting the predetermined composite coil substantially coincides.

  In this way, when the induced voltage is synthesized in a predetermined connection section, reduction of the synthesized value based on the mutual phase difference is avoided, so that the torque sensor TS7 outputs the voltage value of the operation signal in a good state. Is possible.

  In the present embodiment, when the common polarities of all the coil coils La1 to La3 constituting the composite coil LA approach, the common polarities of the other composite coils (LB and LC) do not approach. Even in the composite coil LB and the composite coil, the same operation is performed.

  In this way, it becomes easy to distinguish between the timing of the operation signal generated by the composite coil LA and the timing of the operation signal generated by another composite coil (LB or LC). A high direction signal Sr can be output.

  In this embodiment, the torque sensor TS8 may be constituted by an induction generator by replacing the rotor as shown in FIG. In such a case, the magnetic flux generators described in the claims are the surfaces M1 to M6 formed between the pillars BM, and the polarities thereof are alternately arranged as before. It becomes.

  FIG. 16 shows a mechanism around the drive shaft (angular velocity amplification mechanism) according to a new embodiment. As shown in the drawing, two main gears 701 and 702 are mounted on the drive shaft 211. The main gears 701 and 702 are fixed to the drive shaft by a knock pin of the boss portion, and rotate according to a handle operation.

  A shift box CB is provided on the side of the drive shaft 211. The shift box CB includes a signal generation circuit, a torque sensor TS12 including a stator and a rotor, a sub shaft 530 on which the stator is attached, cases 500, 511, and 512, covers 521 and 522, and a bearing 541. And 542, peripheral parts for fixing the bearing, and sub gears 601 and 602.

  The sub shaft 530 is rotatably fixed to the case of the gear box CB, and rotates together with the rotor 312 according to the handle operation. The sub-shaft 530 receives the handle operating torque via the main gear and the sub-gear, and in this embodiment, the gear ratio between the main gear and the sub-gear is “3: 1”. In addition, the stator 311 is fixed to the case 500 and is arranged so as to rotate the rotor 312 inside the stator 311.

  17A shows a state in which the torque sensor TS9 is directly fixed to the drive shaft, and FIG. 17B shows a state in which the torque sensor TS10 is fixed to the sub shaft of the transmission box. In both cases, the same stator and rotor are used.

  In the torque sensor TS9, an angular velocity ω0 is applied to the drive shaft 211 according to the steering operation, and the moving speed of the magnetic pole at that time is V0. In this case, fluctuations in the magnetic flux of the coil occur according to the moving speed V0 of the magnetic pole, and when the drive shaft 211 rotates once (corresponding to T0) as shown in FIG. The sine curve appears.

  On the other hand, in the torque sensor TS10 according to this embodiment (see FIG. 17b), when the angular velocity similar to that in FIG. 17A is given to the drive shaft, the angular velocity ω1 that is three times as great is given to the sub shaft 530. In this case, the rotor rotates at a speed three times that of the rotor in the torque sensor TS9. For this reason, the magnetic poles arranged on the rotor of the torque sensor TS10 move at a speed V1 that is three times that of the magnetic poles of the torque sensor TS9.

  FIG. 18B shows the waveform of the operation signal output from the torque sensor TS10. Such an operation signal forms a sine curve for nine cycles because the sub shaft 530 rotates three times while the drive shaft 211 rotates one time (corresponding to T0). In this case, at the coil end, the magnetic pole crosses at a speed three times as fast as the speed V0 (see FIG. 17), and the amount of change in the magnetic flux increases accordingly. For this reason, the output value (voltage value) of the operation signal increases as the magnetic flux change amount increases.

  As described above, according to the torque sensor of the present embodiment, it is possible to increase the amount of change in magnetic flux and increase the amplitude value of the operation signal by amplifying the rotational speed of the rotor. This also makes it possible to increase the value of the torque signal St output from the signal processing circuit 400.

  Although the embodiment according to the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical idea described in the claims. It is. Specifically, in the signal generation circuit according to the second embodiment, the composite coil is a parallel circuit, but the present invention is not limited to this, and a series circuit may be used. In this case, the voltage value of the operation signal can be increased by exciting each of the composite coils simultaneously. The composite coil may be a combination of parallel connection and series connection as appropriate.

  Further, the number of coils of the signal generation circuit and the number of poles of the rotor magnetic pole are not limited to those introduced in the embodiments, and are appropriately within the scope of the technical idea described in the claims. It can be added and changed.

DESCRIPTION OF SYMBOLS 100 Electric power steering apparatus TS Torque sensor for power steering 310 Generator 311 Rotor 312 Stator 313 Signal generation circuit 400 Signal processing circuit

Claims (15)

A rotor that rotates in response to a handle operation, a signal generation circuit including a composite coil composed of at least two or more coils, and magnetic flux generation in which a relative positional variation with respect to the coil occurs in response to the handle operation And a stator that constitutes a generator by being combined with the rotor, the signal generation circuit, and the magnetic flux generation unit,
The composite coil is wired in a connection section that generates a predetermined phase voltage in the signal generation circuit, and generates an operation signal by synthesizing induced electromotive forces generated in the coils in the connection section. Torque sensor for steering.   2. The power steering torque sensor according to claim 1, wherein the signal generation circuit includes a plurality of the connection sections, the composite coil is provided in each of the connection sections, and the plurality of operation signals are generated. .   The power steering torque sensor according to claim 1, wherein the signal generation circuit is provided in the stator.   4. The power steering torque sensor according to claim 1, wherein at least two coils constituting the composite coil are connected in parallel to the composite coil. 5.   4. The power steering torque sensor according to claim 1, wherein all the coils constituting the composite coil are connected in parallel to the composite coil. 5.   6. The power steering torque sensor according to claim 1, wherein all coils formed in the signal generation circuit have the same winding direction.   The coils having the same connection section among the coils formed in the signal generation circuit are arranged at equal intervals in the circumferential direction of the rotor or the stator. 6. A torque sensor for power steering according to 6.   8. The power steering torque sensor according to claim 1, wherein all coils formed in the signal generating circuit are arranged at equal intervals in a circumferential direction of the rotor or the stator. 9. . The magnetic flux generator is configured to form at least four poles alternately arranged in the circumferential direction of the rotor or the stator,
9. The at least two or more coils having the same connection section among the coils formed in the signal generation circuit have a common polarity approaching at substantially the same timing. The torque sensor for power steering as described. The magnetic flux generator is configured to form at least four poles alternately arranged in the circumferential direction of the rotor or the stator,
The power according to any one of claims 1 to 8, wherein a common polarity approaches at substantially the same timing to all coils formed in the signal generation circuit and having the same connection section. Torque sensor for steering.   The timing at which the common polarity approaches each of the coils forming one connection section of the connection sections, and the timing at which the common polarity approaches each of the coils forming the other connection sections other than the one connection section. The torque sensor for power steering according to claim 1, wherein the torque sensors are different.   12. The torque sensor for power steering according to claim 1, further comprising an angular velocity amplification mechanism that increases an angular velocity of the rotor more than an angular velocity of the steering shaft. A rotor that rotates in response to a handle operation, a signal generation circuit that forms a coil and generates an operation signal based on an induced electromotive force generated in the coil, and a relative positional variation with respect to the coil corresponds to the handle operation. A magnetic flux generating section generated by the above, and a stator that constitutes a generator by being combined with the rotor, the signal generating circuit, and the magnetic flux generating section,
The power steering torque sensor, wherein the magnetic flux generator has at least four poles arranged alternately in the circumferential direction of the rotor or the stator.   A rotor that rotates in response to a steering wheel operation, an angular velocity amplifying mechanism that increases the angular velocity of the rotor over the angular velocity of the steering shaft, and a coil is formed and an operation signal is generated based on an induced electromotive force generated in the coil. A generator is configured by combining a signal generation circuit, a magnetic flux generation unit in which a relative position variation with respect to the coil is generated in response to the handle operation, and the rotor, the signal generation circuit, and the magnetic flux generation unit. And a power steering torque sensor. An electric power steering apparatus comprising the power steering torque sensor according to any one of claims 1 to 14.

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