JPH0476825B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric power steering device, and more particularly to a steering rotation detection means for detecting the rotation speed of a steering system.

(Prior Art) An electric power steering device includes a steering force booster using an electric motor as a power source and its control circuit, as well as a steering torque detecting means for detecting the steering torque applied to the steering wheel and a steering system. It is equipped with a steering rotation detection means for detecting the steering rotation speed, and based on these detection signals, a control circuit generates an auxiliary torque to the electric motor.
The aim is to reduce steering force and improve steering feel.

The steering rotation detection means in this conventional electric power steering device includes a light shielding plate that is provided coaxially with the input shaft and has a plurality of slits formed at equal intervals in the radial direction on the outer circumference of the light shielding plate. It consists of a photocoupler (photoelectric pickup) attached to the steering column with a light shielding plate in between, and the steering system detects the transmitted light that is interrupted by the light shielding plate by converting it into a pulsed electrical signal. For example, the rotation speed is detected based on the rotation of the motor.

(Problems to be Solved by the Invention) However, in the case of the rotation detection device in such a conventional electric power steering device,
Generally, the maximum rotation speed of the steering system is 100
[rpm], it is difficult to detect information such as the speed in a short period of time (about several microseconds to several milliseconds), making it difficult to improve the responsiveness of the electric power steering device. Furthermore, since the electric power steering device has many rotating elements, sliding elements, etc., lubricating grease is used in those parts, and this grease blocks the light from the rotation detection device. If the light is reflected or diffusely reflected, there is a risk that an error will occur in the detected value and a good steering feeling may not be obtained.

Therefore, the present invention has been made to solve these conventional problems, and its purpose is to easily detect information such as the rotational speed of the steering system in a short period of time. An object of the present invention is to provide an electric power steering device having a steering rotation detecting means that improves the responsiveness of the steering device and can always provide a good steering feeling without the risk of detection errors caused by the influence of grease or the like.

(Means and operations for solving the problems) In order to solve the above problems, the present invention provides a steering torque detection means 41 for detecting the steering torque of the steering system, and a steering rotation detection means for detecting the rotation speed of the steering system. 45 and both detection means 41, 45
In the electric power steering apparatus, the steering rotation detection means 45 is a generator (tachogenerator) connected to the steering system, so that the steering system is For example, the rotational speed can be obtained as a DC voltage, and its direction can be obtained by the polarity of the DC voltage, so that the magnitude and direction of the rotational speed can be obtained instantaneously. Furthermore, since no optical system or the like is required, it is not affected by grease or the like, and there is no possibility of detection errors occurring.

(Embodiment) A preferred embodiment of the present invention will be described below based on the accompanying drawings.

FIG. 1 is an overall configuration diagram showing an electric power steering device according to an embodiment of the present invention, and FIG. 2 is a vertical view showing the same device 1 bent at a 90° cut plane. In FIG. 2, 1 is an electric power steering device, 2 is a steering column, 3 is a stator, and 4 and 5 are an input shaft and an output shaft coaxially arranged with each other.

The inner end of the input shaft 4 is rotatably supported within the inner end of the output shaft 5 via a bearing 11.
These inner ends are connected by a torsion bar 12, and the input shaft 4 is connected to the output shaft 5 by bearings 11 and 13.
are rotatably supported by bearings 14 and 15, respectively. Furthermore, a steering rotation sensor 16 which constitutes a steering rotation detection means is arranged around the input shaft 4, a steering torque sensor 17 is arranged around the fitting part of the input/output shafts 4 and 5, and a steering torque sensor 17 is arranged around the output shaft 5. It includes a control device 20 that drives and controls the electric motor 18 based on detection signals from the electric motor 18, reduction gear 19, steering rotation sensor 16, and steering torque sensor 17.

To explain in more detail, the steering rotation sensor 16 is
It is composed of a DC generator 16a fixed to the outer periphery of the column 2. This generator 16a has a rotating shaft disposed along the axis of the input shaft 4, and the input shaft 4 corresponds to the pulley 16b attached to the end of the shaft.
A belt groove 4a is formed on the outer periphery of the belt.

The belt 1 is connected to the belt groove 4a and the pulley 16b.
The generator 16a rotates as the input shaft 4 rotates, and a detection signal corresponding to the rotation direction and rotation speed of the input shaft 4 is output. The outer diameter of the pulley 16b on the belt groove is smaller than the outer diameter on the belt groove 4a of the input shaft 4, and the generator 16a is designed such that the rotational speed of its rotor is greater than the rotational speed of the input shaft 4. connected.

The steering torque sensor 17 is composed of a cylindrical movable iron core 17a provided on the outer periphery of the fitting portion of the input shaft 4 and the output shaft 5 so as to be displaceable in the axial direction, and a coil portion 17b fixed to the inner periphery of the steering column. It consists of a differential transformer. The movable iron core 17a is
A pin 17e protruding from each protruding piece 5a of the output shaft 5
Then, shift the input shaft 4 by 90 degrees with respect to this pin 17e.
Elongated holes 17 that respectively engage pins 17f protruding from the
g and 17h, and when an angular difference occurs in the circumferential direction between the input shaft 4 and the output shaft 5, the movable iron core 17a will be displaced in the axial direction due to the engagement relationship between them, and the amount of displacement is It corresponds to the steering torque applied to the input shaft 4. The movable iron core 17a has a central part made of a magnetic material, and a good conductor non-magnetic material 1 at both ends.
7i is integrally provided. Also, movable iron core 1
7a is biased from the right end by a spring 17j made of non-magnetic material, and is connected to the pins 17e, 17f and the elongated hole 17.
This prevents lost motion due to gaps of g and 17h. The coil section 17b, which is disposed around the movable core 17a, includes a primary coil 17k to which an alternating current signal such as a pulse is input, and a primary coil 17k that outputs an output signal corresponding to the displacement of the movable core 17a.
A pair of secondary coils 17l arranged on both sides of k,
It consists of 17m. Therefore, the torsion bar 12
The angular difference between the input shaft 4 and the output shaft 5 due to the torsion of
This results in an axial displacement of the movable iron core 17a, which is converted into an electrical signal by the secondary coils 17l and 17m and output.

The electric motor 18 includes a stator 3 integrally provided on the steering column 2, and at least a pair of magnets 3a fixed to the inner peripheral surface of the stator 3.
, a rotor 18a rotatably disposed around the output shaft 5, and a brush 18d that is pressed in the radial direction by a spring 18c within a brush holder 18b fixed to the stator 3. Rotor 18a
is equipped with a cylindrical shaft 18e rotatably supported by bearings 21 and 22, and on the outer periphery of this cylindrical shaft 18e there is a laminated iron core 18f having a skew groove and a multiple winding 1.
8g are integrally encased one after another, and a minute gap is provided around the outer periphery of the magnet 3a and the iron core 18f. Further, the cylindrical shaft 18e is provided with a commutator 18h connected to the multiplex winding 18g, and the brush 18d is pressed into contact with the commutator 18h.

The speed reduction mechanism 19 includes two stages of planetary mechanisms 23 and 24 arranged around the output shaft 5. The front planetary mechanism 23 is fitted into the inner peripheral surface of the case 25 from its rear end (left end side in the figure), and
Contact portion 3 formed between case 25 and stator 3
A ring roller 27 elastically supported by a spring 26 in the direction a is engaged with the other end side (left end side in the figure) of the cylinder shaft 18e, and is movable in the axial direction and rotatable integrally in the circumferential direction. A sun roller 28 is provided on the outer periphery of the sun roller 28, and a friction surface 28b is formed on the outer periphery of the sun roller 28.
9b... is formed on the planetary roller 29;
The first carrier member 30 pivotally supports the planetary roller 29. Rear planetary mechanism 24
is the common ring roller 27, a sun roller 31 which is encircled around the output shaft 5 and whose friction surface is the outer periphery of a cylindrical body which is integrally connected to the first carrier member 30, and which is interposed between these. Consisting of a planetary roller 32 whose outer periphery is a friction surface, and a second carrier member 33 that pivotally supports the planetary roller 32, the second carrier member 33 has an inner end that is connected to the rear end of the output shaft 5. The ring body 34 is rotatably supported by a support member 35 attached to the case 3 side via a bearing 15, and a spline is attached to the rear end of the output shaft 5. They are connected by engagement.

Now, the ring roller 27, each sun roller 2
8 and 31 and the planetary rollers 29 and 32 are each made of metal (for example, iron, aluminum, etc.), and each friction surface has a substantially V-shaped groove in cross section that can be fitted into each other. and planetary rollers 29, 32 are 27
b..., 29b..., 32b... are divided in the axial direction at the tops of the substantially V-shaped grooves, and each divided member 27a..., 29a..., 32a... moves independently in the axial direction. It is set up so that it is possible.

In this configuration, steering torque is applied to the input shaft 4, and torque is transmitted from the input shaft 4 to the output shaft 5 via the torsion bar 12, and the direction of the steering torque and the torque are determined by the steering torque sensor 17 and the steering rotation sensor 16. When the amount is detected, signal processing is performed by the control device 20, and the brush 18
A control voltage is supplied to the multiplex winding 18g via d, and the electric motor 18 rotates in the same direction as the steering torque. The rotational torque of the rotor 18a of the electric motor 18 is reduced by the speed reduction mechanism 19 and transmitted to the output shaft 5 via the first carrier member 23 and the second carrier member 24.

Next, the control device 20 will be explained based on FIG. 3.

In FIG. 3, 67 is a control section, 40 is a microcomputer, and 47 is an A/D converter.

The steering torque detecting means 41 appropriately frequency-divides the clock pulse inside the microcomputer 40 to the steering torque sensor 17 and the primary coil 17k of this steering torque sensor 17, converts it into a rectangular wave or sine wave alternating current, and generates a current. A drive unit 42 that amplifies, rectifier circuits 43A and 43B that rectify each electrical signal obtained from the secondary coils 17l and 17m in response to the displacement of the movable iron core 17a, and removes high frequency components to create a stable DC voltage. It is composed of low-pass filters 44A and 44B for conversion.

The steering rotation detection means 45 includes the steering rotation sensor 16
It is comprised of a DC generator 16a, and a preprocessing circuit 46 that preprocesses the output of the DC generator 16a and inputs it to the A/D converter.

FIGS. 10 to 15 are diagrams showing embodiments of this preprocessing circuit.

First, in the first embodiment shown in FIGS. 10 and 11, one of the output terminals of the generator 16a is directly connected to the A/D converter 47 of the control device 20, and the other terminal is fixed. Voltage circuit 7
0 to the A/D converter 47. The constant voltage circuit 70 is composed of a resistor _R0 connected to the A power supply of the power supply circuit of the control device 20, and a Zener diode ZD connected in series with the resistor R0, and the voltage applied to the Zener diode ZD is
Vz is a preset constant value. Therefore,
As shown in FIG. 11, among the output signals S ₃ and S ₄ input to the A/D converter 47, the output signal S ₄ has a constant voltage Vz, and the output signal S ₃ induced by the generator 16a has a predetermined voltage. The signal is superimposed on the voltage Vz, and as a result, the A/D converter 47 can process it based on the predetermined voltage value Vz, and detect the steering rotation speed using a single positive power source as a battery power source. Therefore, a negative power supply can be made unnecessary, and the power supply circuit can be simplified.

Furthermore, the A/D converter 47 converts the output signals S ₃ and S ₄ into digital signals and inputs them to the microcomputer 40 . The microcomputer 40 sequentially reads the output signals _S3 and _S4 and then performs the calculation _S3 - _S4 , thereby obtaining the steering rotational speed S as shown in FIG.

Next, a second embodiment shown in FIGS. 12 and 13 will be described. In the second embodiment, the generator 1
One output terminal of 6a is connected to the inverting terminal of operational amplifier 71 via resistor _R1 , and
It is connected to the non-inverting terminal of operational amplifier 72 via R ₂ . The other output terminal of the generator 16a is
It is connected to the non-inverting terminal of operational amplifier 71 via resistor R ₃ and to the inverting terminal of operational amplifier 72 via resistor R ₄ . The operational amplifiers 71 and 72 have their output terminals and non-inverting terminals connected via resistors R ₅ and R ₆ , respectively.
An arithmetic circuit 73 is constituted by two operational amplifiers 71 and 72 and resistors R ₁ to R ₆ . Therefore,
When voltage υa is induced at the output terminal of the generator 16a, one operational amplifier 72 performs the calculation V ₁ −V ₂ , and the other operational amplifier 71 performs the calculation V ₂ −V ₁ . As shown in FIG. 13, the operational amplifier 72 outputs an output signal _S3 , and the operational amplifier 71 outputs an output signal _S4 .

Furthermore, these output signals S ₃ and S ₄ are sent to the control device 20 via low-pass filters 74 and 75, respectively.
The signal is input to the A/D converter 47 , where it is digitally converted and input to the microcomputer 40 . In the microcomputer 40, after sequentially reading each output signal _S3 , _S4, the calculation _S3 - _S4 is performed, thereby obtaining the steering rotational speed S as shown in FIG.

Furthermore, the third embodiment shown in FIGS. 14 and 15 is
A preprocessing circuit 46c is constructed by interposing the constant voltage circuit 70 of the first embodiment between one output terminal of the generator 16a and the subtraction circuit 73 of the second embodiment. Therefore, as shown in FIG. 15, the voltage output to the other output terminal of the generator 16a
V ₂ becomes a predetermined voltage Vz, and the voltage V ₁ generated at one output terminal becomes a voltage value υb superimposed on the predetermined voltage Vz. The output voltage of both these output terminals is
As in the previous embodiment, in the subtraction circuit 73, V ₁
-V ₂ and V ₂ -V ₁ are performed, and output signals S ₃ and S ₄ as shown in FIG. 15 are obtained from the steering rotation detection means 45.

Further, the microcomputer 40 performs the calculation process S=S ₃ -S ₄ , and the first
A steering rotational speed S as shown in FIG. 5 is obtained.

In addition, in such a preprocessing circuit 46, the steering rotation speed can be detected with a positive single power supply, and in particular, in the circuit 46c shown in the third embodiment, a constant voltage is applied to the other output terminal of the generator. Since a circuit is added and the generator output signals are subtracted from each other in the subtraction circuit, even if changes due to noise or temperature fluctuations are mixed into these output signals S ₃ and S ₄ , they will cancel each other out. It is possible to improve the noise characteristics and temperature characteristics of the steering rotation detection means.

Now, returning to FIG. 3, the microcomputer 40 includes an I/O port, a memory, a calculation section, a control section, and the like. microcomputer 40
The power supply circuit 49 that drives the on-vehicle battery 5
A relay circuit 53 is connected to the (+) terminal of 0 via the key switch 50 of the ignition key and a fuse 52 and cuts off the power in the event of an abnormality, and a constant voltage circuit 54 is connected to the output side of this relay circuit 53. The A terminal on the output side of the relay circuit 53 supplies power to a motor drive means 55, which will be described later, and the B terminal, which is the output terminal of the constant voltage circuit 54, supplies power to the microcomputer 40, each detection means 41,
45 and other control units. At this time, the power supply voltage supplied to the motor driving means 55 is detected by the voltage detection sensor 65A, which is the power supply voltage detection means 65. In the above configuration, when the key switch 51 is turned on, the microcomputer 40 controls each detection means 4 based on a command.
The output signals S ₁ to S 5 of Nos. 1, 45, and ₆₅ are digitally converted and taken in by the A/D converter 47, processed according to the program written in the memory, and control signals T ₂ and T _{3 that} drive the electric motor 18 are generated. and T ₄ ' are outputted to the motor drive means 55 to drive and control the motor 18.

The electric motor driving means 55 includes a drive unit 56
and FET (field effect transistor) 57, 58, 5
9 and 60, and series circuits 66, 67, 68, and 69 of resistors and capacitors connected in parallel thereto. In the bridge circuit, the drain terminals of FETs 57 and 60 are connected to the A terminal of the power supply circuit 49, while the source terminals of these FETs are connected to the drain terminals of the other FETs 58 and 59, respectively. The source terminals of FETs 48 and 49 are connected to the common side, respectively.

The gate terminals of FETs 47, 48, 49, and 50 are connected to the output side of the drive unit 56, and the source terminals of FET 57 and FET 60, which are the output side of the bridge circuit, are connected to the armature winding 18g of the motor 18. It is connected. The drive unit 56 turns on the FET 57 based on the motor rotation direction control signals T ₂ and T ₃ from the microcomputer 40, and simultaneously turns on the FET 59.
drive the FET 59 based on the motor drive signal T ₄ ' consisting of a PWM signal, or turn on the FET 60 and simultaneously turn the FET 59 on.
58 is enabled to drive, and the FET 58 is driven based on a motor drive signal T ₄ ' consisting of a PWM signal. Therefore, in the motor drive means 55,
One FET57 ON drive and FET59 PWN drive, or the other FET60 ON drive and FET58
By PWM driving, the electric motor 33 receives control signals T ₂ ,
The rotation direction and its power (rotation speed and torque) are controlled according to T ₃ and T ₄ '.

Next, the operation based on this configuration will be explained.

FIG. 4 is a flowchart showing an outline of the motor control processing in the microcomputer 40, and P ₁ to P33 in the figure indicate each step of the flowchart.

When the key switch 51 of the ignition key is turned on, power is supplied to the microcomputer 40 and other circuits, and control is started. first,
In the microcomputer 40, the steps
At P ₁ , each register and data in RAM are cleared. Then, in steps P ₂ and P ₃ , the steering torque detection signals S ₁ and S ₂ are sequentially fetched, and the
S ₁ −S ₂ is calculated in P ₄ and this is set as the steering torque T. Let the steering torque be T. Here, since the steering torque sensor 17 is composed of a differential transformer,
The relationship between the steering torque and the detection signals S ₁ , S ₂ and T is shown in FIG.

In step _P5 , in order to determine the direction of action of the steering torque T, it is determined whether it is positive or negative. If it is positive or zero, step _P6 sets F=0 and proceeds to step _P9 ; if negative, proceeds to step _P7 , sets F=1, and then converts the absolute value in step _P8 , that is, T=- T's processing. Here, F indicates the sign of the steering torque, that is, the direction of action.
In step _P9 , the contents of the memory whose address is the absolute value T of the steering torque are called. In the memory, the product of the armature current I _M of the motor 18 corresponding to the absolute value T of the steering torque shown in FIG. 6 and the resistance R _M of the armature wire, brushes, wiring, etc., that is, R _M · A table 1 is configured in which the duty conversion value D(T) of I _M is stored. Therefore, the steps
In step _P9 , the contents of the memory corresponding to the address depending on the absolute value T of the steering torque, that is, the duty conversion value D(T) of R _M and I _M are called, and the process proceeds to step _P10.
Proceed to. In step _P10 , the value of F is determined in order to give a sign to the addressed duty conversion value D(T). If F=0, the steering torque is zero or positive, so the duty converted value D(T) is transferred as is. If F=1, the steering torque is negative, so proceed to step _P11 and transfer the duty converted value D. Transfer and store (T) as a negative value, and proceed to step _P12 .

Next, in steps P ₁₂ and P ₁₃ , the steering rotation speed detection signal S ₃ from the steering rotation detection means 45 is
S ₄ is read sequentially, and S ₃ −S ₄ is read in step P ₁₄ .
is calculated and set as the steering rotational speed S. Here, detection signals S ₃ and S ₄ from the steering rotation detection means 45
and S are shown as in FIG. 7, which are output signals based on the preprocessing circuit 46B of the second embodiment shown in FIG.

In step _P15 , in order to determine the direction of the steering rotational speed S, it is determined whether it is positive or negative. If S is positive or zero, proceed to step _P16 and set F=0.
If S is negative, proceed to step _P17 and set F=1.
After that, absolute value conversion, that is, S=-S processing is performed in step _P18 . At step _P19 , the absolute value S of the steering rotational speed is read as the address and the contents of the memory. In the memory, the electric motor 18 corresponding to the absolute value S of the steering rotation speed shown in FIG.
In order to determine the rotation speed S _M of the motor 18, a table 2 is constructed in which the product of the induced electromotive force constant k and the rotation speed S _M of the electric motor 18, that is, the duty conversion value D(S) of k·S _M is stored. Therefore, the memory contents corresponding to the address based on the absolute value S of the steering rotational speed, ie, the duty conversion value of S _M , are called, and the process proceeds to step _P20 .

In step _P20 , the value of F is determined in order to give a sign to the addressed duty conversion value D(S). If F=0, the steering rotational speed is positive, so the duty conversion value D(S) is transferred as is, and F
If =1, the steering rotational speed is negative, so the process proceeds to step _P21 , where the duty conversion value D(S) is transferred and stored as a negative value, and the duty conversion value D based on the steering torque T is determined at step _P22 . (T)
and the duty conversion value D(S) based on the steering rotation speed, and this value is set as _T4 .

Thereafter, in steps _P23 to _P25 , a program is executed to correct the obtained control signal _T4 in accordance with fluctuations in the power supply voltage supplied to the motor drive means 55.

First, in step _P23 , the voltage detection sensor 6
Read the detected value _S5 of 5A, set it as V, and proceed to the next step.
At _P24 , the contents of the memory having this detected value V as an address are called. As shown in FIG. 9, a correction coefficient K for the control signal _T4 corresponding to the power supply voltage V is determined in the memory. Then, in step _P25 , the control signal is multiplied by this correction coefficient to perform correction, and this value is set as T ₄ '.

Step _P26 determines the sign of this corrected value in order to determine the direction of action of the auxiliary torque to be output. If it is positive or zero, it is further determined whether it is positive or zero in step _P27 , and if it is zero, step
Set T ₂ = T ₃ = 0 in P ₂₈ , and if positive, set T ₂ = 1 and T ₃ = 0 in step P ₂₉ .
Each is output as P ₃₂ . On the other hand, if the value of T ₄ ' is negative, T ₂ = 0 and T ₃ = 1 are set in step P ₃₀ , and the absolute value of T ₄ ' is newly set in step P ₃₁ .
After converting to T ₄ ', the values of T ₂ and T ₃ are output at step P ₃₂ , and then the value of T ₄ ' is output at step P ₃₃ .

In this way, the direction of the torque to be assisted is determined by the sign of T ₄ ', that is, the values of T ₂ and T ₃ , and the absolute value of the torque to be assisted is determined by the absolute value of T ₄ '.
As shown in the figure, the signal is output to the drive unit 56 of the motor drive means 55.

At this time, since the value of T ₄ ', that is, the control signal is corrected according to the fluctuation in the power supply voltage value supplied to the motor drive means 55, the motor 1
8, stable control is performed without being affected by fluctuations in the power supply voltage, and a good steering feeling is always obtained.

(Effects of the Invention) As is clear from the above description, according to the present invention, since the steering rotation detection means is constituted by a generator, the rotation speed of the steering system, for example, is determined as a DC voltage, and the direction thereof is determined as a DC voltage. The magnitude and direction of the rotational speed can be determined instantly based on the polarity. Furthermore, since no optical system or the like is required, there is no possibility of detection errors being caused by grease or the like.

In addition, in the preprocessing circuit in this example,
With the addition of a constant voltage circuit, the steering rotation speed can be detected using a single positive power supply, and since the generator output signals are subtracted from each other in the subtraction circuit, these output signals S ₃ and S ₄ are free from noise and temperature. Even if changes due to fluctuations are mixed in, they cancel each other out, making it possible to improve the noise characteristics and temperature characteristics of the steering rotation detection means.

Furthermore, the electric power steering device of this embodiment is provided with a voltage detection sensor that detects the power supply voltage supplied to the motor drive means and a correction means that corrects the motor control signal according to the output signal of the sensor. Even if the voltage fluctuates, the desired output torque can be obtained without being affected by this, and a good steering feeling can always be obtained.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of an electric power steering device according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view showing the electric power steering device bent at a 90° cut plane, and Fig. 3 is a control Overall configuration diagram of the device,
FIG. 4 is a flowchart showing an outline of the control process;
5 is a diagram showing the detection characteristics of the steering torque detection means, FIG. 6 is a diagram showing the relationship between the steering torque detection value and the duty conversion value, FIG. 7 is a diagram showing the detection characteristics of the steering rotation detection means, and FIG. Figure 9 shows the relationship between the detected steering rotational speed value and duty conversion value, Figure 9 shows the relationship between the detected power supply voltage value and the correction coefficient, and Figure 10 shows the relationship between the detected value of the power supply voltage and the correction coefficient.
15 through 15 are diagrams showing embodiments of the preprocessing circuit. In the drawing, 16a is a generator, 45 is a steering rotation detection means, 46 is a preprocessing circuit, 55 is a motor drive means, 64 is a motor control signal generation means, 65 is a power supply voltage detection means, 66 is a correction means, and 67 is a In the control means, S ₁ and S ₂ are steering torque detection signals, S ₃ and S ₄ are steering rotational speed detection signals, and T ₂ , T ₃ and T ₄ ' are electric motor control signals.

Claims (1)

[Scope of Claims] 1. Steering torque detection means for detecting the steering torque of the steering system, steering rotation detection means for detecting the rotational speed of the steering system, and electric motor drive for driving the electric motor based on detection signals from both detection means. 1. An electric power steering apparatus comprising: a steering rotation detecting means comprising a generator (tachogenerator) connected to the steering system. 2. The electric power steering device according to claim 1, wherein the generator is connected such that the rotation speed of its rotor is greater than the rotation speed of the steering system.