JPH043350B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric power steering device that generates auxiliary torque by a steering force booster using an electric motor.

(Prior Art) Examples of electric power steering devices include "Japanese Patent Application No. 59-192390 (see Japanese Patent Application Laid-Open No. 61-81866)" and "Japanese Patent Application No. 59-241959" filed by the applicant of the present application.
(Refer to Japanese Patent Application Laid-Open No. 119468/1983).

This type of electric power steering device is equipped with a steering force booster using an electric motor as a power source and its control circuit, detects the steering torque applied to the steering wheel, and uses the control circuit based on this steering torque signal. By generating auxiliary torque in the electric motor, the steering force is reduced. In addition, in a control circuit constituted by an analog circuit, feedback control is performed using an analog electric signal of the electric motor, thereby making it possible to control the electric motor at a high speed and appropriately improving steering performance.

(Problems to be Solved by the Invention) However, when controlling the electric motor as described above using a microcomputer, due to the characteristics of the microcomputer, it is not possible to read many inputs at the same time, and the microcomputer has internal Since the control operates based on the clock pulses that the control unit has, it takes a certain amount of time for signal processing, so it takes a long time to complete the control, especially with conventional feedback control that repeats the feedback loop many times. Responsiveness may decrease. Therefore, it has been difficult to adequately follow various changes in the steering device, and to appropriately improve the steering feeling.

(Objective of the Invention) Therefore, the present invention improves the response performance of the electric motor without performing feedback control by determining the armature voltage of the electric motor based on the steering torque detection signal and the steering speed detection signal in a microcomputer. It is an object of the present invention to provide an electric power steering device that can sufficiently cope with the operation of the steering device and provide an optimal steering feeling.

(Means for solving problems and their effects) FIG. 1 is an overall configuration diagram of the present invention.

In the device of the present invention, when the key switch of the ignition key is turned on, the steering torque detecting means 77,
Each detection signal is output from the steering rotation detection means 82 and the motor rotation speed detection means 120. When the steering wheel is steered, a motor control signal for the electric motor is determined and outputted by the motor control signal generating means based on the steering torque detection signal from the steering torque detecting means 77 and the steering speed detection signal from the steering rotation detecting means 82. . On the other hand, based on the detection signals from the steering rotation detection means 82 and the motor rotation speed detection means 120, the rotation speed comparison and discrimination means detects the deviation M between the rotation speed N _S of the steering system and the rotation speed N _M of the electric motor, and detects this deviation. When the value exceeds a predetermined range M _O , a correction signal is output. Based on this correction signal, the motor control signal is corrected in the control signal correction means, and the corrected control signal is output. Then, based on the corrected control signal, the motor drive means 100 rotates the motor in the steering direction to generate auxiliary torque.

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

FIG. 2 is a longitudinal sectional view showing the electromagnetic booster of this embodiment bent at 90°. In Fig. 2, 1 is a steering column, 2 is a stator,
3 is a case, and 4 and 7 are an input shaft and an output shaft coaxially arranged with each other. In the electric power steering device of this embodiment, the inner end of the input shaft 4 is loosely fitted into the inner end of the output shaft 7, and these inner ends are connected by a torsion bar 8, so that the input shaft 4 is connected to the bearing 9. , 10, the output shaft 7 is connected to the bearing 1
1, 12, and 13, each of which is rotatably supported. Further, a steering rotation sensor 20 disposed around the input shaft 4, a steering torque sensor 24 disposed around the fitting portion of the input/output shafts 4 and 7, and a steering torque sensor 24 disposed around the output shaft 7. The electric motor 33 and the electromagnetic clutch 63 are activated based on detection signals from the electric motor 33, the reduction gear device 50, the electromagnetic clutch 63, the steering rotation sensor 20, and the steering torque sensor 24.
This configuration includes a control device 75 that drives and controls the.

More specifically, the input shaft 4 is divided into a first shaft 5 and a cylindrical second shaft 6, and a steering wheel, which is a handle, is fixed to the outer end side of the first shaft 5 (the right end side in the figure). A cylindrical second shaft 6 is connected to the inner end via a rubber bush 14 for preventing vibration transmission. This rubber bushing 14 consists of an inner cylinder 14a and an outer cylinder 14b made of metal, and an elastic member 14c interposed between them.The inner cylinder 14a is connected to the first shaft 5, and the outer cylinder 14b is connected to the second shaft 6. Each is fixed. In addition, as shown in Figure 3, the first
An annular member 15 having a protrusion 15a protruding in the radial direction is mounted on the shaft 5, and the protrusion 15a is attached to a second
It is inserted into a notched groove 6a formed on one end side of the shaft 6 (right end side in the figure) with an appropriate gap. Therefore, the first shaft 5 and the second shaft 6 are connected to the rubber bush 1.
4, the first shaft 5 and the second shaft 6 are engaged after being twisted by a predetermined angle due to the gap, and the structure is such that a load of more than a predetermined torque is not applied to the elastic member 14c in the torsional direction. It's summery.
Incidentally, 16 is a circlip for preventing it from coming off.

In addition, on the other end side of the second shaft 6 (left end side in the figure),
As shown in FIGS. 4a to 4c, grooves 17 along the axial direction
are formed at 180° intervals, and projecting pieces 7a that protrude in the axial direction from the inner end side of the output shaft 7 whose diameter has been enlarged to correspond to the grooves 17 are inserted into each groove 17 at predetermined intervals. A small diameter portion formed on the other end side of the second shaft 6 is supported within the enlarged diameter portion of the output shaft 7 via a bearing 11. Furthermore, a torsion bar 8 is disposed along the axis in the hole formed on the inner end side of the second shaft 6 and the output shaft 7, and one end side (right end side) of the torsion bar 8 is connected to the second shaft by a pin 18. 6, while the other end of the torsion bar 8 is fixed to pin 1.
9 is fixed to the output shaft 7. The outer end of the output shaft 7 is connected to another shaft on the load side by a spline formed therein. Therefore, the steering torque applied to the input shaft 4 by the handle is transmitted to the output shaft 7 and the load side through the torsion of the torsion bar 8. The rigidity of the rubber bush 14 is higher than that of the torsion bar 8.

As shown in FIG. 5, the steering rotation sensor 20 includes a plurality of protrusions 21 protruding from the outer periphery of the second shaft 6 at equal intervals in the radial direction, and a plurality of protrusions 21 attached to the steering column 1 so as to sandwich the protrusions 21. It is composed of an attached photocoupler (photoelectric pickup) 22, receives transmitted light interrupted by the protrusion 21, converts the received light into a pulsed electric signal, and outputs it.

The steering torque sensor 24 includes a cylindrical movable iron core 25 provided on the outer periphery of a fitting portion between the second shaft 6 and the output shaft 7 so as to be displaceable in the axial direction, and a steering column 1.
It is constituted by a differential transformer consisting of a coil portion 28 fixed to the inner circumference. The movable iron core 25 is connected to each projecting piece 7a of the output shaft 7, as shown in FIGS.
Elongated holes 25a and 25b are provided to engage with pins 26 protruding from the second shaft 6, and pins 27 protruding from the second shaft 6 at an angle of 90 degrees with respect to these pins 26, respectively. The elongated hole 25a is formed along the axial direction, while the elongated hole 25b is formed inclined at a predetermined angle with respect to the axial direction. Therefore, when an angle difference occurs between the second shaft 6 and the output shaft 7 in the circumferential direction, the long hole 25b and the pin 26 and the long hole 25a and the pin 27
Due to the engagement relationship, the movable core 25 moves in the axial direction, and the movable core 25 is displaced in response to the steering torque applied to the second shaft 6.

Further, a coil section 28 provided around the movable iron core 25 is connected to a primary coil 2 to which a pulse signal is input.
9, and a pair of secondary coils 30 and 31 disposed coaxially on both sides of a primary coil 29 that outputs an output signal corresponding to the displacement of the movable iron core 25.
Therefore, when an angular difference occurs between the second shaft 6 and the output shaft 7 due to the twisting of the torsion bar 8,
The axial displacement of the movable iron core 25 is converted into an electrical signal and output.

Next, the electric motor 33 includes a cylindrical stator 2 that is integrally fixed to the steering column 1 and the case 3 by bolts 34, and at least one pair of magnets 36 that are fixed to the inner surface of the stator 2.
A rotor 3 rotatably arranged around an output shaft 7
It consists of 7. The rotor 37 has bearings 12 and 1
The stator 2 is rotatably mounted on the output shaft 7 via the bearings 11A and 13A.
and a cylindrical shaft 38 supported by the case 3, an iron core 39 having a skew groove on the outer periphery of the cylindrical shaft 38,
A first multiplex winding 40 and a second multiplex winding 41 are integrally encased one after another, and a minute air gap is provided between the magnet 36 and the second multiplex winding 41. Further, the cylindrical shaft 38 has a first multiplex winding 4.
0 and a second commutator 43 connected to the second multiplex winding 41.
Furthermore, a brush 44 that comes into pressure contact with the first commutator 42 is housed in a brush holder 45 that is fixed to the stator 2, and a brush 46 that comes into pressure contact with the second commutator 43 is housed in a brush holder 47 that is fixed to the case.
Lead wires connected to each of the brushes 44 and 46 are taken out to the outside of the stator 2 through non-magnetic pipes. The magnet 36, the first multiplex winding 40, the first commutator 42, and the brush 44 constitute a generator (motor rotation speed sensor) 48 that detects the rotation speed of the rotor 37. A DC voltage proportional to the rotation speed of the rotor 37 is output. On the other hand, the magnet 36, the second multiplex winding 41, the second commutator 43, and the brush 46 constitute an electric motor 33 that generates auxiliary torque.

The speed reduction device 50 includes a two-stage planetary gear mechanism 51 and 52 arranged around the output shaft 7.
The planetary gear mechanism 51 at the front stage includes a common internal gear 53 formed on the inner peripheral surface of the case 3, a sun gear 38a formed on the outer periphery of the other end side (the left end side in the figure) of the cylinder shaft 38, and these. Three planetary gears 5 meshed with
4, and a first carrier member 55 that pivotally supports the planetary gear 54. The planetary gear mechanism 52 in the latter stage includes the common internal gear 53 and a sun gear 56a formed on the outer periphery of a cylinder 56 that is encircled around the output shaft 7 and integrally connected to the first carrier member 55.
, three planetary gears 57 that mesh with these, and a second carrier member 58 that pivotally supports these planetary gears 57. Moreover, this second carrier member 5
A cylindrical body 60 supported by the output shaft 7 is integrally connected to the inner edge of the case 8 via a bearing 59, while a cylindrical body 61 along the inner circumference of the case 3 is integrally connected to the outer edge thereof. , internal teeth 61a are formed in the circumferential direction on the inner circumferential surface of this cylindrical body 61. Therefore, when the rotor 37 of the electric motor 33 rotates, the rotation of the rotor 37 is transferred to the cylinder 61 via the cylinder shaft 38, the planetary gear 54, the first carrier member 55, the planetary gear 57, and the second carrier member 58. It is transmitted while being decelerated.

The electromagnetic clutch 63 has a rotor 64 that
It is rotatably supported via a bearing 66 by an annular body 65 spline-coupled to the outer periphery of the output shaft 7, and is fixed to the output shaft 7 via an annular elastic member 67 that absorbs torsional vibrations. Further, the rotor 64 is formed in a cylindrical shape, and extends to the periphery of the cylindrical body 60 of the second carrier member 58, and has a pair of projections 64a that protrude radially from the inner surface of this extending portion toward the outer periphery of the output shaft 7. is installed protrudingly. These protrusions 64a
As shown in FIG. 6, the groove 65a is inserted into a cutout groove 65a formed in the annular body 65 with a required gap in the circumferential direction, and has an engaging relationship with the annular body 65 in the circumferential direction. are doing. Therefore, the rotor 64 and the output shaft 7 are located within the gap, that is, the rotor 6
Until the projection 64a of No. 4 and the ring body 65 are engaged, they are in an elastically connected state. Further, external teeth 64b are formed on the outer periphery of the extending portion of the rotor 64, and the second carrier member 58 of this extending portion
A disk-shaped support plate 64c is provided in a protruding manner on the opposite side. Between this support plate 64c and the second carrier member 58, a disc-shaped plate 68 having a groove on its outer periphery that engages with the internal teeth 61a of the cylindrical body 61 is provided.
and disk-shaped plates 69 having grooves on their inner peripheries that mesh with the external teeth 64b of the rotor 64 are arranged alternately to constitute a multi-plate clutch mechanism. In addition,
In the figure, 70 is a stopper for the plate 69. Further, a frame body 71 having a U-shaped longitudinal section is fixed to the case 3, and a ring-shaped excitation coil 72 is housed within the frame body 71. The excitation coil 72 is connected to a control device 75 through a lead wire. There is. Therefore, the electromagnetic force generated as the excitation coil 72 is energized attracts the plates 69 and 68 toward the excitation coil 72, so that the rotational torque of the electric motor 33 transmitted via the reduction gear device 50 is multi-plate. It is transmitted to the output shaft 7 through the clutch mechanism and the protrusion 64a of the rotor 64.

Furthermore, the control device 75 will be explained based on FIG. 7.

In FIG. 7, 76 is a microcomputer, and the microcomputer 76 receives detection signals from a steering torque detection means 77, a steering rotation detection means 82, a vehicle speed detection means 86, an electric motor rotation speed detection means 120, and an abnormality detection means 114. _S1 to _S7 are input.

The steering torque detection means 77 includes the steering torque sensor 24, a drive unit 78 that divides and outputs the clock pulse _T1 inside the microcomputer 76 to the primary coil 29 of the steering torque sensor 24, and Rectifier circuits 79A and 79B that rectify the analog electrical signals obtained from the secondary coils 30 and 31, respectively, and a low-pass filter 80 that removes high frequency components.
A, 80B and this low pass filter 80A, 8
It is comprised of an A/D converter 81 that converts each analog electrical signal from 0B into a digital signal and inputs it to the microcomputer 76 as steering torque detection signals S ₁ and S ₂ . The motor rotation speed detection means 120 consists of a motor rotation speed sensor 48 and a low-pass filter 121 that removes high frequency components of this analog output voltage. Rotation speed detection signal compatible with several N _M
Output as _S3 . The steering rotation detection means 82 includes the steering rotation sensor 20 and the steering rotation sensor 2.
a pulse conversion circuit 83 that supplies power to the light emitting part of the photocoupler 22 of No. 0 and converts the electric signal outputted by the light receiving part into an appropriate pulse signal and outputs the pulse signal;
A waveform shaping circuit 84 that shapes this output signal calculates the steering speed based on the pulse signal output from the waveform shaping circuit 84 and the clock pulse of the microcomputer 76, and outputs the steering speed detection signal _S4 . A drive unit 85 counts the number of signal pulses and outputs a steering angle signal _S5 . Further, the vehicle speed detection means 86 includes, for example, a vehicle speed sensor 89 consisting of a magnet 87 that rotates together with the speedometer cable and a reed switch 88 that is turned on and off as the magnet rotates, and a reed switch 88 that supplies power to the reed switch 88. a pulse conversion circuit 90 that outputs the intermittent signal as a pulse signal, a waveform shaping circuit 91 that shapes and outputs this output signal, and an output signal from the waveform shaping circuit 91 and a microcomputer 76.
A drive unit 91A calculates the vehicle speed based on the clock pulse of the vehicle and outputs a vehicle speed detection signal _S6 .
It is composed of.

The microcomputer 76 has an I/O port,
It is composed of a memory, a calculation section, and a control section. The power supply circuit 92 that drives the microcopy computer 76 and the like has a relay circuit 96 connected to the + terminal of an on-vehicle battery 93 via a key switch 94 of an ignition key and a fuse 95, and an output side of the relay circuit 96. constant voltage circuit 9 connected to
A on the output side of the relay circuit 96
Power is supplied from the terminal to a motor drive means 100 and an electromagnetic clutch drive means 108, which will be described later.
Power is supplied from the B terminal of the constant voltage circuit 97 to the microcomputer 76 and other control units. Therefore, when the key switch 94 is turned on, the microcomputer 76 processes each of the input detection signals S ₁ to S ₇ according to the program written in the memory, and generates a control signal for driving the electric motor.
output T ₃ , T ₄ , T ₅ and a current control signal T ₆ for driving the electromagnetic clutch to the motor drive means 100 and the electromagnetic clutch drive means 108, respectively;
The electric motor 33 and the electromagnetic clutch 63 are driven and controlled. In addition, T ₃ and T ₄ are electric motors 3 corresponding to the steering direction.
3 clockwise rotation direction signal and left rotation direction signal, T ₅
is the motor control signal that determines the armature voltage.

The motor drive means 100 includes a drive unit 1
01, relays 102 and 103, and transistors 104 and 105. The bridge circuit consists of relays 102 and 10.
3 is connected to the A terminal of the power supply circuit 92,
The emitters of transistors 104 and 105 are connected to the common side (ground) via a resistor 106. The excitation coils of each relay 102, 103 and the bases of transistors 104, 105 are connected to the output side of the drive unit 101.
An armature winding (second multiple winding) 41 of the electric motor 33 is connected between the collectors of the motor 5. The drive unit 101 drives the relay 102 or 103 and the transistor 105 or 104 based on the rotation direction signals T ₃ and T ₄ from the microcomputer 76, and also drives the motor control signal.
A pulse signal subjected to pulse width conversion (PWM modulation) based on T ₅ is output to the base of either transistor 104 or 105. Therefore, in the motor driving means 100, the direction of rotation of the motor 33 is controlled by energizing one relay 102 and transistor 105, or the other relay 103 and transistor 104, and the rotation direction of each transistor 104, 105 is controlled. The energization time of the transistors 104 and 105 is controlled by a pulse signal applied to the base. An armature voltage V _A corresponding to the energization time control is applied to the electric motor 33, and the electric motor 33 is controlled to generate an auxiliary torque corresponding to the steering torque applied to the steering wheel.

The electromagnetic clutch driving means 108 consists of a drive unit 109 and a transistor 110. The collector of the transistor 110 and the power supply circuit 92
The excitation coil 7 of the electromagnetic clutch 63 is connected between the A terminals of the
2 are connected. The emitter of the transistor 110 is connected to the common side through a resistor 111,
The base is connected to the output side of the drive unit 109. Furthermore, the drive unit 109 outputs a pulse signal whose pulse width has been converted based on the control signal T ₆ to the transistor 110 . Therefore, in the electromagnetic clutch driving means 108, the drive unit 109 controls the energization of the transistor 110 based on the current control signal _T6 from the microcomputer 76, and accordingly, the torque coupling force of the electromagnetic clutch 63 is reduced. is controlled.

Further, in this embodiment, abnormality detection means 114 for detecting abnormalities in the electric motor 33 and the electromagnetic clutch 63 is provided. This abnormality detection means 114
is an amplifier 11 that amplifies the terminal voltage of the resistor 106.
5A, an amplifier 115B that amplifies the terminal voltage of the resistor 111, low-pass filters 116A and 116B that remove high frequency components, and these detected voltages are converted into a digital signal _S7 and input to the microcomputer 76. A/D converter 117
It is composed of. This abnormality detection means 11
4 detects, for example, an abnormality in the electric motor 33 or the electromagnetic clutch 63 by the terminal voltage of each resistor 106 and 111, and in the case of an abnormality, outputs a relay control signal _T2 to the relay circuit 96 of the power supply circuit 92, It is used for abnormality diagnosis and the like to stop the power supply from 92.

Next, the action will be explained.

FIG. 8 is a flowchart showing an outline of the control processing in the microcomputer 76, and P ₁ to _{P 13} in the figure indicate each step of the flowchart.

Ignition key switch 94 is ON
When the power is turned on, power is supplied to the microcomputer 76 and other circuits, and control begins. First, the microcomputer 76 reads the detection signals S ₁ to S ₇ from each detection means 77, 82, 86, 114, and 120, and determines whether the detection signals (S ₁ to _{S 7} ) are appropriate in step T ₁ . Fault diagnosis is performed in a subroutine. In case of an abnormality, a relay control signal is sent from the microcomputer 76.
T ₂ is output to the relay circuit 96, the power supply from the power supply circuit 92 is cut off, the drive of the electric power steering device is stopped, and a manual steering operation is performed. If each of the detection signals _S1 to _S7 is normal, it is determined in step _P2 whether the vehicle speed n is smaller than a predetermined speed _n0 based on the vehicle speed detection signal _S6 . If the vehicle speed n is higher than a predetermined speed, the control pattern 1 shifts to another control pattern 1, in which, for example, after gradually reducing the armature voltage of the motor 33 and the excitation current of the electromagnetic clutch 63, control is performed to stop these operations. be exposed.

If the vehicle speed n is less than the predetermined speed _n0 , the step
At _P3 , the magnitudes of the steering torque detection signals _S1 and _S2 from the steering torque detection means 77 are compared to determine whether the steering direction of the steering wheel is rightward or leftward, and whether the steering direction signal _T3 is rightward or leftward is determined. Rotation direction signal T ₄
A decision will be made. Then, in step _P4 , based on the steering torque detection signals _S1 and _S2, D=
|S ₁ −S ₂ | is calculated. Next, in step _P5 , unload control is performed. That is,
When the steering angle is larger than the predetermined value C based on the steering angle signal _S5 , it is determined that the steering wheel is close to the steering end, and D=D−X
Performs correction calculations.

In step _P6 , the steering rotation detection means 8
The steering speed N _S is determined by the steering speed detection signal _S4 from 2.
The steering speed N _S and the calculated value D are used to specify the address of the armature voltage V _A previously stored in the memory. In other words, the steering speed detection signal
_S4 is used as the motor rotation speed N _M because the electric motor 33 is connected to the output shaft 7 via the reduction gear 50 and the electromagnetic clutch 63, so the steering speed and the motor rotation speed are basically proportional. This is because the steering speed can be regarded as the motor rotation speed _NM , and the memory stores various values that can be determined by addressing the motor rotation speed _NM and the calculated value D as shown in FIGS. 9 and 10. Armature voltage V ₁ ~
V _o is stored, and by addressing these calculated values D and steering speed N _S , a motor control signal T ₅ corresponding to the armatures V ₁ to _{V o} can be determined. Therefore, since the armature voltage V _A is determined by addressing based on the steering torque detection signals S ₁ and S ₂ and the steering speed detection signal S ₃ , the control speed can also be increased in the microcomputer 76 .

Also, in the control signal _T6 of the electromagnetic clutch 63, the address of the clutch current Ic corresponding to the calculated value D is specified in step _P7 in the same manner as described above. Calculated value D and clutch current Ic in this case
The relationship with is shown in FIGS. 9 and 11.
Then, an electromagnetic clutch control signal corresponding to the clutch current Ic is generated by addressing based on the calculated value D.
T ₆ is determined. In FIG. 11, I _C0 is a current value corresponding to a preload that can absorb frictional force and the like.

Next, in step _P8 , the steering rotation speed N _S obtained by the steering speed detection S ₄ from the steering rotation detection means 82 and the motor rotation speed obtained from the motor rotation speed detection signal S ₃ from the motor rotation speed detection means 120 are determined. The deviation M from N _M is calculated. This deviation M can also be determined, for example, by the ratio of the steering rotational speed N _S and the motor rotational speed N _M multiplied by the reduction ratio of the reduction gear device 50 . In step _P9 ,
The magnitude of the deviation M is determined, and if the deviation M is smaller than a predetermined value (within an allowable range) _M0 , the motor control signal _T5 and the electromagnetic clutch control signal _T6 are directly processed at step _P13 without being corrected. Each control signal
T ₃・T ₄ , T ₅ , and T ₆ are output. Deviation M is a predetermined value
If M is greater than ₀ , in step P ₁₀
A comparative judgment is made between N _S and N _M. If N _S > N _M , the control signal T ₅ is corrected to increase in step P ₁₁ so as to increase the armature voltage V _A of the motor 33 and increase the rotational speed N _M. Then, the electromagnetic clutch control signal _T6 is corrected to increase. On the other hand, if N _S <N _M ,
In step _P12 , the control signals _T5 and _T6 are corrected to reduce N _M of the electric motor 33,
Proceed to step _P13 . These control signals T ₅ and
By correcting T ₆ , fluctuations in the steering feel due to minute fluctuations in the electric motor 33 or due to the friction elements of the speed reducer 50 and the electromagnetic clutch 63 are reduced.

In step P ₁₃ , the rotation direction signals T ₃ and T ₄
Then, the corrected motor control signal T ₅ is output to the motor drive means 100 and the electromagnetic clutch control signal T ₆ is output to the electromagnetic clutch drive means 108 . In the motor drive means 100, the rotation direction signal
Electric motor 33 based on T ₃ and T ₄ and control signal T ₅
PWM control of the armature voltage V _A is performed. At the same time, in the electromagnetic clutch driving means 108, PWM control of the clutch current Ic of the electromagnetic clutch 63 is performed based on the control signal _T6 , so that the torque coupling of the electromagnetic clutch 63 becomes the armature current Ia, that is, the rotational torque of the electric motor 33. This will prevent the electromagnetic clutch 63 from consuming excessive drive current.

As a result, the relationship between the load torque applied to the output shaft 7 and the steering torque applied to the input shaft 4 is obtained as a characteristic shown in FIG. 12. In other words, the steering torque applied to the input shaft 4 is obtained as a curve indicated by L with respect to the time of manual operation indicated by l, and in the A region where the load torque is small, it is approximately the same as that during manual operation, and in the region A where the load torque is increased, it is obtained as a curve indicated by L. It maintains a substantially constant value in the range, and the steering torque can be appropriately reduced in the case of a large load torque.

(Effects of the Invention) As explained above, according to the present invention, the armature voltage is determined by the microcomputer based on the steering torque detection signal and the steering speed detection signal, so it is possible to increase the control speed of the electric motor. , it is possible to sufficiently cope with the operation of the steering device and to improve the steering feeling.

In addition, by finely adjusting the motor rotation speed based on the steering speed detection signal and the motor rotation speed detection signal, minute fluctuations in the output characteristics of the motor can be prevented.
Since the influence of minute fluctuations caused by the reduction gear, electromagnetic clutch, bearing, etc. can be reduced, the steering feeling can be further improved. Furthermore, in the above embodiment, since the armature voltage previously stored in the memory is output by addressing,
The control speed of the electric motor can be further increased.

[Brief explanation of drawings]

Figure 1 is an overall configuration diagram of the present invention, Figures 2 to 12
The figure shows an embodiment of the electric power steering device of the present invention, and FIG. 2 shows the electromagnetic booster.
A vertical cross-sectional view shown by bending at a 90° cutting plane, FIG. 3 is a cross-sectional view taken in the direction of the − arrow in FIG. 2, FIG. 4 a is a cross-sectional view taken in the − arrow direction of FIG. 2, and FIGS. 4 b, c are the plan view and side view of the movable iron piece, and Figure 5 is - in Figure 2.
6 is a sectional view taken along the - arrow in FIG. 2, FIG. 7 is an overall configuration diagram of the control device, FIG. 8 is a flowchart showing an outline of control processing, and FIG. 9 is a torque signal. Diagram showing the relationship between and armature current, No. 10
The figure shows the relationship between armature current, motor rotation speed, and motor torque. Figure 11 shows the relationship between armature current and clutch current. Figure 12 shows the relationship between steering torque and load torque. It is a diagram. In the drawings, 33... electric motor, 77... steering torque detection means, 82... steering rotation detection means, 100...
...Electric motor drive signal, 120...Motor rotation speed detection means, _S1 , _S2 ...Steering torque detection means, _S3 ...
Motor rotation speed detection signal, S ₄ ... Steering speed detection signal, T ₃ , T ₄ , T ₅ ... Motor control signal.

Claims (1)

[Claims] 1. In an electric power steering device equipped with an electric motor that generates an auxiliary torque corresponding to the steering torque of the steering system, a steering torque detection means for detecting the steering torque of the steering system and a steering rotation detection means for detecting the rotation speed of the steering system a motor rotation speed detection means for detecting the rotation speed of the electric motor; and a motor control for determining and outputting a motor control signal for the electric motor based on a detection signal from the steering torque detection means and a detection signal from the steering rotation detection means. The signal generating means compares the steering rotation speed and the motor rotation speed based on detection signals from the steering rotation detection means and the motor rotation speed detection means, and outputs a correction signal when the deviation exceeds a predetermined range. A rotational speed comparison and determination means, a control signal correction means for correcting the motor control signal using a correction signal from the rotational speed comparison and determination means, and a motor drive means for driving the electric motor based on an output signal from the control signal correction means. An electric power steering device characterized by comprising: