JPS6234852A - Motor-driven steering device - Google Patents

Abstract

PURPOSE:To make it possible to detect instantly the quantity and the direction of the rotation speed, by using a generator linked to a steering system (tachogenerator) as a steering rotation detecting device to detect the rotation speed of the steering system. CONSTITUTION:The captioned device generates motor control signals by a motor control signal generating device 64 depending on the outputs of a steering torque detecting device 41 to detect the steering torque of the steering system and a steering rotation detecting device 45 to detect the rotation speed of the steering system. And the control signal is corrected in a correcting device 66 depending on the output of a power supply voltage detecting device 65, and a motor driving device 55 is controlled by the said control signal after correction. In this case, a generator 16a rotated linking to the input shaft of the steering device is used as a steering rotation detecting device 45, and one output terminal thereof is connected directly to an A/D converter 47, while the other terminal is connected to the A/D converter 47 through a constant voltage circuit 70.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention provides FMl for an electric power steering device,
In particular, the present invention relates 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. A steering rotation detection circuit is provided to detect the steering rotation speed, and based on these detection signals, a control circuit generates an auxiliary torque to the electric motor to reduce the steering force and improve the steering feeling.

The steering rotation detection means in this conventional electric power steering device is sunk coaxially with the input shaft, and has a plurality of slits formed at equal intervals in the radial direction on the outer circumference thereof. It consists of a light shielding plate and a photocoupler (photoelectric pickup) attached to the steering column so as to sandwich the light shielding plate, and the light transmitted through the light shielding plate is converted into a pulsed electrical signal and detected. By doing so, it is possible to detect, for example, the rotational speed based on the rotation of the steering system.

(Problems to be Solved by the Invention) However, in the rotation detection device of such a conventional electric power steering device, since the rotation speed of the steering system is generally as low as about 100 rpm at the maximum, the speed etc. information for 1a hour (several p sec
~ several m5ec) is difficult to detect, and 'If
It becomes difficult to improve the responsiveness of the dynamic power steering device (7). 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, making it impossible to obtain a good steering feeling.

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. Js reduces the responsiveness of the steering system and also causes detection errors due to the influence of grease, etc.
An object of the present invention is to provide an electric power steering device having a steering rotation detection means that can always provide a good steering feeling without any trouble.

(Means and operations for solving the problems) In order to solve the problems described in -, the present invention provides a steering torque detection means (41) for detecting the steering torque of the steering system, and a steering torque detection means (41) for detecting the rotational speed of the steering system. In an electric power steering device comprising a steering rotation detection means (45) and a motor drive means (55) for driving an electric motor based on detection signals from rain detection means (41) and (45), the steering rotation detection means Since the means (45) is a generator (tachogenerator) connected to the steering system, for example, the rotational speed of the steering system is set as a DC voltage, and its direction is set as a DC voltage.
N is obtained by the polarity of the voltage, and 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 with reference to 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 shows the device (1) at 9
FIG. 3 is a vertical sectional view showing the device bent at a 0° cut plane. In Figure 2, (1) is an electric power steering device, (2)
is the steering column, (3) is the stator, (4) and (
5) is an input shaft and an output shaft arranged coaxially 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 (If), while these inner ends are connected by a torsion bar (12).
The input shaft (4) is rotatably supported by bearings (11) and (13), and the output shaft (5) is rotatably supported by bearings (14) and (15), respectively. Furthermore, a steering rotation sensor (16) constituting a steering rotation detection means around the input shaft (4);
A steering torque sensor (17) arranged around the fitting part of the input/output shaft (4) and (5), an electric m (1B) arranged around the output shaft (5), a reduction gear ( 19), and a control device (20) that drives and controls the electric motor a (18) based on detection signals from the steering rotation sensor (16) and the steering torque sensor (17).

To explain in more detail, the steering rotation sensor (16) is as follows.

It is composed of a DC generator (18a) fixed to the outer periphery of the column (2). This generator (lea) has its rotating shaft disposed along the axis of the input shaft (4), and corresponds to the pulley (lflb) attached to the end of the shaft.
A belt groove (4a) is formed on the outer periphery of the belt.

This belt groove (4a) and pulley (tab) have a belt (
16c) is suspended, and as the input shaft (4) rotates, the power generation a (18a) 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 belt groove J: of the pulley (tab) is smaller than the outer diameter of the belt groove (4a)-H of the input shaft (4),
The rotating shaft of the generator (lfla) is configured to have a large speed ratio with respect to the input shaft (4).

The steering torque sensor (17) has 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) with an axial displacement +T The movable core (17a) is composed of a differential transformer consisting of a coil part (17b) fixed to the inner circumference of the column.
A bottle (1?) protruding from each protruding piece (5a) of the output shaft (5).
e), and elongated holes (17g) and (17h) that respectively engage with pins (17f) protruding from the input shaft (4) at an angle of 80＠ with respect to the pin (17e), and the movable iron core (+
7a), when an angular difference occurs in the circumferential direction between the input shaft (4) and the output shaft (5), the engagement relationship between them causes displacement in the axial direction. corresponds to the steering torque applied to The movable iron core (+7a) has a central part made of magnetic material, and a good conductor non-magnetic material (1
7i) is provided in one piece. In addition, the movable iron core (17
a) is biased from the right end by a spring (170) made of non-magnetic material, and a pin (17e).

(17f) Toffl holes (t7g), (t'h) Prevents missing holes. A coil section (17b) disposed around the movable iron core (17a)
) is the primary coil (
17k), and a pair of secondary coils (17m), which output an output signal corresponding to the displacement of the movable iron core (17a) and are disposed on both sides of the primary coil (17k). Therefore, due to the torsion of the torsion bar (12), the difference in angle between the input shaft (4) and the output shaft (5) by one angle is
The axial displacement of a) is the secondary coil (+741),
(layer 17) converts it into an electrical signal and outputs it.

The electric motor a (18) includes a stator (3) provided in two parts on the steering column (2), and this stator (3).
at least one pair of magnets (3a) fixed to the inner circumferential surface of the
18a) and a brush (18d) that is radially pressed by a spring (18c) in a brush holder (18b) fixed to the stator (3).
) includes a sleeve (18e) rotatably supported by bearings (21) and (22), and a laminated core (18f) having a skew groove on the outer periphery of the sleeve (18e).

Multiple windings (18g) are sequentially wrapped around the magnet (3a) and the iron core (18f), and a small gap is provided around the outer periphery of the magnet (3a) and the iron core (18f). In addition, the tube sleeve (18a) has multiple windings & 9 (18
g) and a commutator (18h) connected to the brush (
18d) is pressed.

The speed reduction mechanism (19) consists of a two-stage planetary mechanism (23) and (24) arranged around the output shaft (5). On the inner surface,
It is inserted from the rear end (left side in the figure), and the contact part (
A ring roller (27) elastically supported by a spring (26) in the direction 3a) is engaged with the other end side (left end # in the figure) of the sleeve (18e), and is movable in the axial direction and circumferentially. A sun roller (
28), and a friction surface (29b) interposed between these and on the outer periphery.
... is formed, and a first carrier member (30) that pivotally supports this planetary roller (29). (27), and a sun roller (31) whose friction surface is the outer periphery of a cylindrical body that is encircled around the output shaft (5) and integrally connected to the first carrier member (30).
and a planetary interposed between these, whose outer periphery serves as a friction surface.
It consists of a roller (32) and a second carrier member (33) that pivotally supports the planetary roller (32), and the inner end of the second carrier member (33) is connected to the output shaft (5).
It is attached to a ring (34) mounted on the rear end, and this ring (34) is rotatable via a bearing (15) on a support member (35) attached to the case (3) side. and is connected to the rear end of the output shaft (5) by spline connection.

Now, the ring roller (27), each sun roller (28)
), (31) and planetary roller (29),
The ring rollers (32) are each made of fully bent material (for example, iron or aluminum), and each friction surface has a groove with a roughly V-shaped cross section that can be fitted into the ring roller (27). and planetary rollers (29), (32) are (27b)..., (29b)..., (32b).
At each top of the approximately V-shaped groove, there is a separation in the axial direction.
';l, and each divided member (2?a)...
. . , (29a) . . . , (32a) . . . are provided so as to be movable independently in the axial direction.

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).

Steering torque sensor (17) and steering rotation sensor (16)
When the steering torque direction and torque j1'L are detected by the controller (20), signal processing is performed by the control device (20), and a control voltage is supplied to the multiple winding (18g) via the brush (18d), 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 decelerated 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). Ru.

Next, the second control device (20) will be explained based on FIG.

In FIG. 3, (87) is a control section, and (40
) is a microcomputer, (47) l; iA/D converter.

The steering torque detection means (41) appropriately divides the clock pulse inside the microcomputer (40) to the steering torque sensor (17) and the second coil (17k) of the steering torque sensor (17). Drive unit (42) that converts into rectangular wave or sine wave alternating current and amplifies the current.
and r+ (rectifier circuits (43A) and (43B) that rectify each electric current obtained from the secondary coil (17m) and (17m) in response to the displacement of the dynamic core (17a), and a high frequency It consists of low-pass filters (44A) and (44B) that remove the component and convert it into a stable DC voltage.

The steering rotation detection means (45) is a steering rotation sensor (I6).
This DC generator (LEA) and this DC generator (TEA)
It is comprised of a preprocessing circuit (46) that preprocesses the output of and manually inputs it to the A/D converter.

FIGS. 1O to 15 are diagrams showing embodiments of this preprocessing circuit.

First, in the first embodiment shown in FIGS. 10 and 11, 1
Among the output terminals of the generator (tea), one output terminal is directly connected to the A/D converter/heater (47) of the control device (20).
), and the other output terminal is connected to an A/D converter (47) via a constant voltage circuit (70). The constant voltage circuit (70) is composed of a resistor RO connected to the A power supply of the power supply circuit of the control device (20) and a Zener diode-FZD connected in series with the resistor RO, and a voltage applied to the Zener diode ZD. The voltage Vz becomes a preset constant value. Therefore, as shown in FIG.
Of the output signals S3 and 54 input to the converter (47), the output signal S4 becomes a constant voltage Vz, and the generator (
The output signal 53 induced by 1B, a) is at a predetermined voltage v
As a result, the A/D converter (47) can process the signal based on the predetermined voltage value Vz, and the steering rotation speed can be adjusted by using the positive power supply as the eight power supply. can be detected, a negative power supply can be made unnecessary, and the power supply circuit can be made into a cylinder.

Furthermore, the A/D converter (47) converts the output signals S3 and S4 into digital signals and inputs them to the microcomputer (40). The microcomputer (40) sequentially reads the output signals S3 and S4 and then performs calculations S3-S4.

As a result, a steering rotational speed S as shown in FIG. 11 is obtained.

Next, a second embodiment shown in FIGS. 12 and 13 will be described. In the second embodiment, one output terminal of the generator (lea) is connected to the inverting terminal of the operational amplifier (71) via the resistor R1, and the non-inverting terminal of the operational amplifier (72) via the resistor R2. connected to the terminal. Generator(
lea) is connected to the non-inverting terminal of the operational amplifier (71) via a resistor R3, and to the inverting terminal of the operational amplifier (72) via a resistor R4. The operational amplifiers (71) and (72) have their output terminals and inverting terminals connected to resistors R5 and R6, respectively.
are connected via two operational amplifiers (71),
(72) and resistors R1 to R6 constitute a subtraction circuit (73). Therefore, when voltage υa is induced at the output terminal of the generator (18a), one operational amplifier (7
2), the calculations v and -v2 are performed, and the other operational amplifier (71) performs the calculation V2-Vl, and as shown in FIG. 13, the operational amplifier (72) outputs the output signal -33. However, the operational amplifier (71) outputs an output signal S4.

Moreover, these output signals S3. S4 is connected to the control device (20) via low-pass filters (74) and (75), respectively.
) 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 of the output signals S3 and S4, an operation S3-54 is performed, whereby the steering rotational speed S as shown in FIG. 13 is set.

Furthermore, the third embodiment shown in FIGS. 14 and 15 is a generator (
A pre-processing circuit (48c) was constructed by interposing the constant voltage circuit (70) of the first embodiment between one output terminal of the IEla) and the reducer circuit (73) of the second embodiment. It is something.

Therefore, as shown in FIG.
) is a predetermined voltage V2, and the voltage Vl generated at one output terminal is a voltage value υb that is higher than the predetermined voltage Vz. The output voltages of these two output terminals are determined by the subtraction circuit (as in the previous embodiment).
73), the following arithmetic processing is performed, v, -v2, v2-v, and the steering rotation detection means (45) outputs the first
Output signals S3 and 34 as shown in FIG. 5 are obtained.

Furthermore, in the microcomputer (4o), 5
=S3-54 is performed, and the steering rotational speed S as shown in FIG. 15 is obtained.

In addition, in such a preprocessing circuit (4B), it is possible to detect the steering rotation speed with a single positive power supply.
In the circuit (46c) shown in the third embodiment of 'IIF, a constant voltage circuit is added to the other output terminal of the generator, and a subtraction circuit is used for f? , electric machine output signals, these output signals s3. s.

Even if noise and changes due to temperature fluctuations are mixed in! As a result, the noise characteristic I and temperature characteristic of the steering rotation detection means can be made good.

Now, returning to Fig. 3, the microcomputer (4
0) is equipped with an I10 board, memory, arithmetic unit, control unit, etc. The power supply circuit (48) that drives the microcomputer (40) etc. is connected to the (+) of the vehicle battery (50).
) terminal via the ignition key's key switch (51) and fuse (52).

A relay circuit (53) that cuts off the power in the event of an abnormality, and a constant voltage circuit (53) connected to the output side of this relay circuit (53).
4) and A on the output side of the relay circuit (53).
Power is supplied from the terminal to a motor drive means (55), which will be described later, and from the B terminal, which is the output terminal of the constant voltage circuit (54), a microcomputer (40) and each detection means (41) are supplied.
, (45) and other control units. At this time, the power supply voltage supplied to the motor drive means (55) is detected by the voltage detection sensor (65A) which is the voltage detection means (65). In the configuration described below, when the key switch (51) is turned on, the microcomputer (40) detects each detection means (41) based on the command.
, (45), (135) output signals S1 to S5 as A
/D converter (47) converts it into digital data, imports it, and stores it in memory! The control signal T2. which is processed according to the programmed program and drives the electric motor a (18). T3 and T
4° is output to the motor drive means (55), and the motor (18
) to drive and control.

The electric motor drive means (55) includes a drive unit (56)
and FET ('field effect transistor) (57), (5
8).

(59), (Go) and series circuits of resistors and capacitors connected in parallel to these (6B), (67), (88)
, (69).

In the bridge circuit, the respective drain terminals of FET (57) and (60) are connected to the A terminal of the power supply circuit (49), while their source terminals are connected to the other FET (5
8) and (59), respectively.

The source terminals of FETs (48) and (49) are each connected to the common side.

FET (47), (4B), (49), (50)
Each gate terminal of FE is connected to the output side of the drive unit (5B), and becomes the output side of the bridge circuit.
T (57) source terminal and F E T (flo)
The source terminal of the armature winding (18) of the motor (18)
g). The drive unit (56)
is the motor rotation direction control signal T2. from the microcomputer (40). FET based on T3 (57)
At the same time as turning on FET (59), the motor drive signal T4 consisting of a PWM signal is set to the drive circuit state.
', or drive FET (58) to a driveable state at the same time as FET (EiO) is turned on, and the motor drive signal T4' consisting of a PWM signal is activated. Based on FET (5
day) to drive. Therefore, the motor drive means (55)
In this case, ON driving of one FET (57) and PWM driving of FET (59), or
ON drive of T (80) and P of F E T (58)
Electric #! by WM drive! (33) is the control signal "r2.
The rotation direction and its power (rotation speed and torque) are controlled according to Tl and T4'.

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

FIG. 4 is a flowchart showing an outline of the first motor control process in the microcomputer (40), and P+-P33 in the figure indicates 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 to start control. First, in the microcomputer (40), data in each register and RAM are cleared in step P1. and,
In step P2*P3, the steering torque detection signals S1 and 32 are sequentially fetched, and in step P4, 5t-52
is calculated and 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 steering torque and the detection signal Sl
, S2, and T are shown in FIG.

In step P5, in order to determine the acting direction of the steering torque T, it is determined whether it is positive or negative. If it is positive or true, step P6 sets F=0 and proceeds to step P9; if negative, proceeds to step P7, sets F=1, and then steps P
At, absolute value conversion, that is, T=-T processing is performed. Here, F indicates the sign of the steering torque T, 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. The memory stores the product of the armature current IM of the motor (!8) corresponding to the absolute value T of the steering torque shown in FIG. 6 and the resistance R of the armature winding, brushes, wiring, etc. RM・■H
A table 1 is configured in which duty conversion values D(T) are stored. Therefore, in step P9, the contents of the memory corresponding to the address based on the absolute value T of the steering torque, that is, the duty conversion value D (T) of RM.IN, are called, and the process proceeds to step P1G. In step P10, the value of F is determined in order to increment the addressed duty conversion value D(T) by 4.

If F=O, the steering torque is zero or positive, so the duty converted value D (T) is transferred as is, and if F=1, the steering torque is negative, so the process proceeds to step pH and the duty converted value D ( T) is transferred and stored as a negative value, and the process proceeds to step P12.

Next, step P12. At pH, the steering rotation speed detection signals S3 and 34 from the steering rotation detection means (45)
are sequentially read, S3-34 is calculated in step P14, and this is set as the steering rotation speed S. Here, the detection signals S3, S4, and S from the steering rotation detection means (45) are shown as shown in FIG. Rotational speed S
In order to determine the direction of , it is determined whether it is in or negative. Mo and S
If is positive or zero, proceed to step pHi and set F=O. If S is negative, proceed to step PI7 and set F=1.
After that, at step pH+, absolute value conversion, that is, 5=
- Process S. In step P19, the contents of the memory whose address is the absolute value S of the steering rotational speed are called. In the memory, in order to determine the rotation speed SM of the electric motor (18) corresponding to the absolute value S of the steering rotation speed shown in FIG. 8, the induced electromotive force constant of the electric motor (18) and the rotation speed SH are stored. product, i.e. duty transformation of SH (11'1
Table 2 is configured in which D(S) 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 SM, are called.

Step P: Proceed to 2G.

In step P20, assign a sign to the addressed duty conversion value D(S)! In order to determine the value of F, the value of F is determined. If F=0, the steering rotational speed is positive, and if F=1, the steering rotational speed is negative, so proceed to step P2+ and transfer and store the duty conversion value D (S) as a negative value. , in step P22, the duty conversion value D (T) based on the steering torque T and the duty conversion value D (S) based on the steering rotational speed are added, and this value is set as T4.

Thereafter, in steps P23 to P2S, 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 ``heavy pressure detection sensor (l
Read the detected value S5 of li5A) and set it as V, and proceed to the next step 2.
At step p24, the contents of the memory whose address is V is called out.In the memory, as shown in FIG.
is determined. Then, in step P25, the control signal is multiplied by this correction coefficient to perform correction, and this value is set as T4''.

In step P26, the sign of this Jli value is determined by n in order to determine the acting force direction of the auxiliary torque to be output. And if I[or zero, step P2? Further, it is determined whether it is 1F or zero, and if it is zero, T is determined at step P2B.
2 =:T] =O, and in the case of IE j, ste,
In step P29, T2=1[, L and T3=0 are outputted in step P32. On the other hand, if the value of T4° is negative, T2 = OL + one T3 = 1 in step P3o.
At the same time, in step P31, the absolute value of T4° is newly converted to T4°, and then in step P32, T
2. (1?i of T3 is output, then step P33
The value of T4° is output.

In this way, the sign of T4' is -1L1σ, which is T2. T:1
The direction of the torque to be assisted is determined by the value of , and the absolute value of the torque to be assisted is determined by the absolute value of T4°, and as shown in FIG. is output to.

At this time, the value of T4', that is, the controllability t) is corrected according to the fluctuation of the power supply voltage supplied to the motor drive means (55), so the motor (18) is operated at the power supply voltage. Stable control is performed without being affected by fluctuations, and a good steering feeling is always obtained.

(Effects of the Invention) As is clear from the explanation below, according to the present invention, since the steering rotation detection means is constituted by a generator,
For example, the rotational speed of the steering system 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, there is no possibility of detection errors being caused by grease or the like.

In addition, in the preprocessing circuit in the tree embodiment.

With the addition of a constant voltage circuit, the steering rotation speed can be detected using a single positive power supply, and since the output signals of the generators are subtracted from each other in the subtraction circuit, these output signals s3. Even if noise or changes due to temperature fluctuations are mixed into s4, they cancel each other out, making it possible to improve the noise characteristics and temperature characteristics of the steering rotation detection means.

Further, in the electric power steering device of this embodiment, there is provided an upper pressure detection sensor that detects the power source rE supplied to the motor drive means, and a correction that compensates the motor control signal according to the output signal t3 of the sensor. Since the means is provided, even if the power supply voltage fluctuates, the desired output I/Lux can be obtained without being affected by the fluctuation, and a good steering feeling can always be obtained.

[Brief explanation of the drawing]

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 vertical sectional view showing the 1-shift power steering device bent at a 90” cut plane, and Fig. 3 is an overall configuration diagram of the control device, FIG. 4 is a flowchart showing an outline of control processing), m5fN is a diagram showing the detection characteristics of the steering torque detection means, and FIG. 6 is a diagram showing the relationship between the steering torque detection value and the duty conversion value. 7 is a diagram showing the detection characteristics of the steering rotation detection means, FIG. 8 is a diagram showing the relationship between the detected steering rotation speed value and the duty conversion value, and FIG. 9 is a diagram showing the relationship between the detected value of the power supply pressure and the correction coefficient. A diagram showing the relationship. Figures 10 to 15 are diagrams showing examples of the preprocessing circuit. In the drawings, (16a) is a generator, (45) is a steering rotation detection means, and (46) is a front a processing circuit, (55) a motor drive means, (f14) a motor control signal generation means,
(65) is a power supply voltage detection means, (66) is a correction-L stage,
(67) is a control means, S1. S2 is a steering torque detection signal, and S3 is a steering torque detection signal. S4 is a steering rotational speed detection signal, T2. T3゜T4'
is the motor control signal.

Claims (2)

[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 motor drive means for driving the electric motor based on detection signals from both detection means. An electric power steering device comprising: an electric power steering device, wherein the steering rotation detecting means comprises a generator (tacho generator) connected to the steering system. (2) The electric power steering device according to claim 1, wherein the generator is connected to the steering system so that its rotor has a high speed ratio.