KR100402684B1 - Steering Torque Detecter For Power Steering Wheel - Google Patents

Abstract

The present invention is to detect the torque applied to the steering shaft from the steering wheel in the electric steering apparatus of the automobile to add a torque to the steering shaft or the steering link, such as an electric motor to enable the driver to operate the steering wheel more easily. A steering torque detection device for an electric power steering apparatus, which causes the driving unit to operate in accordance with the detection signal to perform power steering only when a power steering apparatus is required.

The steering torque detection device for an electric power steering apparatus according to the present invention is to be installed on a driver power circuit for adding torque to a steering shaft comprising an input shaft on which a steering wheel is mounted and an output shaft coupled to the input shaft by means of elastic means. Variable resistance means which are respectively provided on the input shaft and the output shaft, are short-circuited by the torsion between the two shafts, and apply a resistance in inverse proportion to the relative rotational displacement amount; Steering direction sensing means for sensing a relative rotational direction of the input shaft relative to the output shaft; Direction control means for controlling an output direction of the driving unit by a signal of the steering direction detecting means; It characterized in that it comprises an amplifier for amplifying the power applied to the short circuit of the variable resistance means applied to the drive unit.

Description

Steering Torque Detection Device for Electric Power Steering Device {Steering Torque Detecter For Power Steering Wheel}

The present invention is to detect the torque applied to the steering shaft from the steering wheel in the electric steering apparatus of the automobile to add a torque to the steering shaft or the steering link, such as an electric motor to enable the driver to operate the steering wheel more easily. The present invention relates to a steering torque detection device for an electric power steering device, in which a drive unit operates according to a detection signal, so that the power steering device only performs power steering when necessary. Particularly, an output of the drive unit is detected by analogously detecting steering torque. By controlling variably, the operation precision of the electric power steering apparatus can be greatly increased, and the steering torque detection device for the electric power steering apparatus with a simple configuration and very low manufacturing cost is provided.

An automobile power steering device is a device for changing the direction of rotation of a vehicle by changing the direction of the rotational axis of the front wheel at an angle proportional to the steering wheel rotation angle by a steering wheel rotated by a driver, in particular a steering shaft rotated by a steering wheel, or By applying torque as a separate driving source to the steering link operated by the steering shaft, the driver can operate the steering wheel more easily by supplementing the rotational force of the steering shaft.

The automobile power steering system is divided into hydraulic type using hydraulic pressure and electric type using driving power of electric motor, depending on the type of power used to supplement the steering shaft torque. The hydraulic automobile power steering system converts oil pump and hydraulic pressure into mechanical torque. The hydraulic actuator, the control device for controlling the operation of the hydraulic actuator and many other components to ensure the correct operation of the components, such as the heavy weight of the complex configuration, which has the disadvantage of greatly increasing the weight of the vehicle The research on electronic power steering is more active than hydraulic.

An automobile steering device is generally composed of a steering wheel operated by a driver and a steering shaft which transmits the rotational force of the steering wheel to a steering link for rotating the wheel. In the case of an electric power steering device, the steering shafts are elastically coupled to each other. It consists of two shafts, the input shaft rotated by the steering wheel and the output shaft coupled to the steering link by elastically twistably coupled to the input shaft by an elastic means, the case that the torque of the steering shaft received from the steering wheel is a certain size or more. It further comprises a steering torque detection sensor for detecting at the torsion angle of the input shaft with respect to the output shaft of the steering shaft, and a driving unit including a steering motor for operating the steering torque or the steering link to apply a steering force to the steering shaft or the steering link. .

With this configuration, the electric power steering apparatus detects the steering torque sensing sensor when the torque applied by the steering wheel to the steering shaft is greater than or equal to a predetermined magnitude, that is, when the torsion angle of the input shaft with respect to the output shaft of the steering shaft becomes greater than or equal to a certain magnitude. When the driver sends a signal, the driving unit operates according to the signal and applies torque to the steering shaft or the steering link to compensate for the steering torque of the steering shaft rotated by the steering wheel.

Therefore, the electric power steering system has a certain amount of torsion angle between the input shaft and the output shaft of the steering shaft when the steering wheel becomes heavy due to the friction of the road surface against the wheel when the vehicle is stopped or at low speed. According to the signal of the steering torque sensor to detect the case of abnormality, the driving unit starts to apply the torque to the steering shaft to make the steering wheel light. On the other hand, at high speeds where the steering wheel is light due to the very small frictional force on the wheels, torque is hardly applied between the input and output shafts of the steering shaft, and the torsion angle between them is very small. The steering torque sensor, which is supposed to generate a signal, does not generate a signal and the driving unit does not operate so that steering is performed only by the pure force of the driver applied to the steering wheel, thereby preventing the steering wheel from being light.

Meanwhile, in the electric power steering apparatus as described above, the steering torque sensor for the conventional electric power steering apparatus mounted to detect the torque of the steering wheel applied to the steering shaft can detect only a torque of a predetermined size or more, so that the traveling speed Has a problem that does not reflect the change in torque according to the change in the power steering operation of the power steering system. For example, when the driving speed is changed, the frictional force of the wheels on the road surface is changed, and the magnitude of the load received from the wheels by the steering shaft is changed. The steering torque detection sensor of the conventional electric power steering system simply detects only when the steering torque is greater than a predetermined size. Since the electronic power steering device of the vehicle is controlled only by the on / off type, there is a problem in that the torque change of the steering wheel according to the load change of the steering shaft is not reflected in the power steering at all. Therefore, when the steering torque is changed near the torque that can be detected by the steering torque sensor due to the change in the driving speed, that is, the load of the wheel, the steering force of the steering wheel changes drastically, which greatly reduces the driver's steering feeling. There was also a problem that greatly hurts the driving stability.

Recently, a steering torque detection device for an electric power steering device has been developed to control the operation of the drive unit by reflecting the load of the steering shaft so that torque of an appropriate size can be compensated for. have.

For example, in Japanese Patent Application Laid-Open No. 8-216899, a retainer, a slider, or the like is provided at a connection portion between an input shaft and an output shaft of a steering shaft, and a relative rotational displacement between them, that is, a torsion angle between the input shaft and an output shaft, is measured. It is equipped with a steering torque detector that measures the torque received by the steering shaft from the steering wheel by measuring the excitation positioner meter and then controls the output of the driving unit based on this.

In addition, the electric power steering apparatuses of Korean Patent Publication Nos. 99-276609 to 11 measure the torsion angle between two axes as light emitting means and light receiving means respectively installed on the input shaft and the output shaft of the steering shaft, and then calculate the complex angle of the electronic controller having the calculation circuit. It is a steering torque detection device configured to calculate torque through the electronic control unit to control the output of the drive unit based on it, and is configured to change the output of the drive unit to supplement the steering torque of the appropriate size to the steering shaft.

In addition, there are several electric power steering devices including a steering torque detection device for the electric power steering device which can reflect the load change of the steering shaft.

However, the conventional steering torque detection devices for the electric power steering apparatus as described above have a steering wheel torque detection means such as a torque sensor, a speed sensing means for detecting the traveling speed of the vehicle and the information detected by the sensing means to produce a steering torque. Comprising an electronic control means for calculating and controlling the output of the drive unit, each of them had the following problems.

First, since the controller calculates the information detected by the steering wheel torque detection means and controls the output of the driver as a signal reflecting the result, there is a problem that discontinuity points exist during steering by discontinuously processing the signal while the steering shaft is rotating. there was. As a result, smooth and smooth steering was not possible.

Second, since the performance can be implemented only through sensitive control means, the manufacturing cost is very high and there is a high possibility of a control error because the control means cannot accurately control the steering force change during the calculation.

Third, there was a high possibility of malfunction during steering had a fatal disadvantage in safety. That is, since the voltage applied to the circuit is not constant due to the influence of the power and / or torque sensor, there is a high possibility of causing unexpected power steering which is different from the driver's intention, and there was a risk of causing an accident due to steering malfunction while driving.

Accordingly, the present invention solves the problems of the conventional steering torque detection devices for the electric power steering apparatus as described above, and the power applied to the driving unit generating torque is varied according to the relative rotational displacement of the input shaft and the output shaft of the steering shaft. It is applied to the drive unit through the variable resistor, and the output of the drive unit can be analogically variably adjusted according to the change in the torsion angle of the input shaft and the output shaft, thereby dramatically improving the responsiveness and operation accuracy of the electric power steering apparatus. It is very simple to provide a steering torque detection device for an electric power steering device with a very low manufacturing cost.

1 is a block diagram of an electric power steering apparatus according to the present invention.

2 is an exploded perspective view of the electric power steering apparatus according to the present invention.

3 is a longitudinal sectional view of the electric power steering apparatus according to the present invention.

Figure 4 is a block diagram of a steering torque detection device for an electric power steering apparatus according to an embodiment of the present invention.

5 is a block diagram of a steering torque detection device for an electric power steering apparatus according to another embodiment of the present invention.

Figure 6 is a graph showing the resistance change according to the steering torque of the variable resistance means of the steering torque detection device for an electric power steering apparatus according to the present invention.

Figure 7 is a graph showing the drive unit current change according to the steering torque of the steering torque detection device for an electric power steering apparatus according to the present invention.

8 is a graph showing the output change of the driving unit according to the steering torque of the electric power steering apparatus according to the present invention.

9 is a graph showing a signal generated according to the steering angle change of the direction control means of the steering torque detection device for an electric power steering apparatus according to the present invention.

Figure 10a is a graph showing the steering force change of the electric power steering apparatus equipped with a steering torque detection device according to the present invention.

Figure 10b is a graph showing the steering force change of the electric power steering apparatus at high speed when the steering torque detection device according to the present invention includes a speed-sensitive variable resistor.

<Description of Symbols for Main Parts of Drawings>

1: steering wheel 2: steering shaft

2a: input shaft 2b: output shaft

3: variable resistance means 30: contactor

31,32: left and right variable resistor 35,36: light emitting device

37: light receiving element 4: steering direction detection means

5 drive unit 6 direction control means

7: amplification unit 8: steering link

9 housing 10 speed variable resistance

Steering torque detection device for an electric power steering apparatus according to the present invention, the steering wheel is composed of an input shaft on which a steering wheel is mounted and an output shaft coupled to the input shaft by means of elastic means to connect the input shaft to a relative rotational displacement with respect to the steering link. It is provided on a power supply circuit for supplying power to a drive unit that adds torque to the shaft, and is provided on the input shaft and the output shaft, respectively, and is short-circuited by the twist between the input shaft and the output shaft, and is inversely proportional to the relative rotational displacement amount. Variable resistance means for applying; Steering direction sensing means for sensing a relative rotational direction of the input shaft relative to the output shaft; Direction control means for controlling an output direction of the driving unit by a signal of the steering direction detecting means; And an amplifier for amplifying the power applied by the short circuit of the variable resistance means and applying the amplified power to the driving unit.

In the above configuration, a preferred configuration of the variable resistance means is installed on the output shaft of the steering shaft spaced apart in the rotational direction of the output shaft, each end having a length in the rotational direction and opposed to each other is connected to the amplification unit, respectively. Left and right variable resistors; And a contactor installed on an input shaft at a position corresponding to the center between the left and right variable resistors to selectively contact the left and right variable resistors according to the rotation of the input shaft to short-circuit power. The resistance means varies the resistance in accordance with the contact position of the contact with the variable resistor.

In addition, the variable resistance means, the left and right light emitting device is installed in the left, right exit hole spaced apart in the rotational direction of the input shaft to the input shaft of the steering shaft; The left and right projected through the left and right exit hole is installed in the entrance hole formed on the output shaft of the position corresponding to the center between the left, right exit hole and selectively overlaps the entrance hole according to the rotation of the input shaft It may include a light receiving element for shorting the power by the light of the light emitting element and inducing a resistance inversely proportional to the amount of light received.

In addition, the steering torque detection device for an electric power steering apparatus according to the present invention, as a preferred configuration, further comprises a speed variable resistor for adding a resistance proportional to the traveling speed to the power input from the variable resistance means to the amplifier. It is done by

On the other hand, the steering direction detecting means is provided on the output shaft spaced apart in the rotational direction of the output shaft, selectively installed by the knob installed on the input shaft and rotated together with the input shaft, the signal according to the direction control means Providing left and right switches provided.

In addition, the direction control means is preferably an electric mechanism configured to transmit the power of the driving unit by selecting the forward and reverse rotation directions with respect to the steering shaft by the power applied through the left and right switches. Do.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an electric power steering apparatus employing a steering torque detection apparatus according to the present invention, Figure 2 is a rear perspective view of the electric power steering apparatus equipped with a steering torque detection apparatus according to an embodiment of the present invention. 3 is a longitudinal cross-sectional view of FIG. 2.

Motorized electric power steering system is a steering shaft that is rotated by steering wheel, especially in steering system that changes the direction of rotation of front wheel by changing steering wheel rotation angle by steering wheel rotated by driver. A steering device configured to allow the driver to operate the steering wheel more easily by adding torque to the steering link operated by the steering shaft or the steering shaft, such as an electric motor, to supplement the rotational force of the steering shaft by the steering wheel. The motorized steering apparatus for automobiles in which the steering torque detection device according to the present invention is mounted is, as illustrated in FIG. 1, a steering wheel 1 to be operated by a driver and a steering shaft 2 on which the steering wheel 1 is mounted. ), And a steering link 8 for transmitting the torque of the steering shaft 2 to the wheel rotation shaft of the vehicle. 2 and 3, the steering shaft 2 is composed of an input shaft 2a and an output shaft 2b coupled to each other by elastic means (not shown) and shielded by the housing 9.

The steering torque detection device according to the present invention is an electric power steering device having the above-described configuration, in which the drive unit 5 detects the magnitude of the torque applied to the steering shaft 2 from the steering wheel 1, and the drive unit 5 detects the detected signal. A power steering device is configured to perform power steering only when a power steering device is required, as shown in FIG. 4, which includes a steering shaft including an input shaft 2a and an output shaft 2b coupled to each other by means of elastic means ( It is installed on each of input and output shafts 2a and 2b of 2) and applies power according to the relative rotation between input and output shafts 2a and 2b, and the relative rotation of the input and output shafts 2a and 2b with respect to the power supply. Variable resistance means (3) for imparting resistance inversely proportional to the amount of displacement; Steering direction sensing means (4) for sensing a rotational direction of the input shaft (2a) with respect to the output shaft (2b); Direction control means (6) for controlling the output direction of the drive unit (5) by the signal of the steering direction detection means (4); A speed variable resistor 10 that detects a driving speed of a vehicle and adds a resistance proportional to the speed, and a power supply that is applied through a short circuit of the variable resistance means 3 and passes through the speed variable resistor 10. And an amplifying unit 7 for amplifying and applying the amplified power to the driving unit 5.

The variable resistance means (3) is installed on a power supply circuit for applying power to the drive unit (5) which gives torque to the steering shaft (2) and the torque magnitude received by the steering shaft (2) from the steering wheel (1). As a power supply of a current (or voltage) proportional thereto to generate a torque proportional to the driving unit 5, the variable resistance means 3 according to an embodiment of the present invention, as shown in FIG. Left and right variable resistors 31 and 32 spaced apart from each other in the rotational direction of the output shaft 2b on the output shaft 2b of the steering shaft 2; And a contactor 30 provided on the input shaft 2a at a position corresponding to the center between the left and right variable resistors 31 and 32. The left and right variable resistors 31 and 32 have lengths in the rotational direction of the contactor 30, and each end of the opposing side is connected to the amplifying circuit of the amplifying unit 7, respectively. In the variable resistance means 3 having such a configuration, when the steering wheel 1 is in the neutral position, the contactor 30 is positioned at the center of the left and right variable resistors 31 and 32, so that the left and right variable resistors ( 31 and 32 are also not in contact with each other, thereby shutting off power to the driving unit 5. In addition, when the steering wheel 1 is operated to either side, the contactor 30 of the input shaft 2a rotated by the steering wheel 1 selectively contacts the left and right variable resistors 31 and 32, and the power supply is activated. The driving unit 5 is driven by applying a power supply by shorting the circuit. At this time, the left and right variable resistors 31 and 32 having the length of the contactor 30 in the rotational direction are proportional to the distance from the contact point to the end of the contactor 30 with respect to the power input to the amplifier 7. The resistance of the input shaft 2a, i.e., the resistance becomes smaller as the rotation angle of the input shaft 2a becomes larger so that the power input to the amplifier 7 becomes larger in proportion to the rotation angle of the input shaft 2a and inversely proportional to the traveling speed. Outputs a torque of a magnitude corresponding to the rotation angle of the input shaft 2a. 6 and 7 are graphs showing the resistance change and the current change of the variable resistance means 3 according to the rotational displacement of the input shaft 2a, and FIG. 8 is a graph showing the output change of the drive unit 5.

The speed variable resistor senses the traveling speed of the vehicle and adds a resistance proportional to the traveling speed with respect to the power applied by the variable resistance means 3 to the amplifier 7. Thus, when the running speed of the vehicle increases, it serves to reduce the size of the power input to the amplifier 7.

The steering direction sensing means 4 is for sensing the rotational direction of the input shaft 2a. According to an embodiment of the present invention, as shown in FIG. 4, the output shaft 2b of the output shaft 2b is disposed on the output shaft 2b. Left and right switches 41 and 42 spaced apart in the rotational direction, and the knob 40 is provided in the center of the input shaft (2a) corresponding to the center of the left and right switches (41, 42) . The steering direction sensing means 4 of this configuration rotates among the left and right switches 41 and 42 while the knob 40 of the input shaft 2a rotates together when the input shaft 2a is rotated in one direction. The tack switch 41 or 42 located on the direction side is pressed to send the corresponding signal to the direction control means 6. 9 is a graph showing a signal generated by the direction control means 6 in accordance with the rotation of the input shaft 2a.

The direction control means 6 changes the rotational direction of the drive part 5 including the forward / reverse electric motor by changing the pole of the power applied to the drive part 5 according to the signal of the steering direction detection means 4. Play a role. That is, it operates by the left and right switches 41 and 42 to control the rotation direction of the driving unit 5 in the direction corresponding to each of the left and right switches 41 and 42.

The amplifier 7 has a power supply amplification circuit such as a transistor, for example, and is applied as a short circuit of the variable resistance means 3 and then amplifies the reduced power while passing through the speed variable resistor 10, and the amplified power supply. By applying to the drive unit 5 serves to increase the output of the drive unit (5).

Steering torque detection device for an electric power steering apparatus according to an embodiment of the present invention according to the configuration having the function as described above, when the torque is applied to the steering shaft (2) from the steering wheel (1), steering The input shaft 2a of the shaft 2 rotates relative to the output shaft 2b at a rotational displacement proportional to its torque, and according to the relative rotation, the contactor 30 of the variable resistance means 3 contacts the variable resistor. Power supplied in proportion to the rotational angle of the input shaft 2a is applied, and the applied power is reduced to a magnitude proportional to the running speed of the speed variable resistor 10 and applied to the amplifier 7. At the same time, one of the left and right switches 41 and 42 of the steering direction sensing means 4 is operated by the knob 40 of the input shaft 2a to apply power to the direction control means 6 and to The control means 6 determines the torque direction by adjusting the pole of the power supply and controlling the forward and reverse rotation direction of the drive unit 5. On the other hand, the amplifier 7 amplifies the power which is changed in proportion to the rotation angle of the input shaft 2a and inversely proportional to the traveling speed while passing through the speed variable resistor 10 from the variable resistance means 3 and applied to the driving unit 5. The driver 5 operates with the amplified power supply to transmit the power in the rotational direction selected by the direction control means 6 to the steering shaft 2 and to supplement the rotational force of the steering shaft 2 by the driver. It makes it possible to operate (1) more easily.

In the above operation, the steering torque detection device for an electric power steering apparatus according to an embodiment of the present invention induces a resistance inversely proportional to the relative rotational displacement amount of the input shaft (2a) and the output shaft (2b) of the steering shaft (2). The driving unit 5 amplifies a power that is proportional to the steering torque of the steering wheel 1 and inversely proportional to the traveling speed, through the variable resistance means 3 and the speed variable resistance 10 that induces a resistance proportional to the traveling speed. The driving unit 5 can apply to the steering shaft 2 a steering force which is sensitively changed analogously according to the change in the torsion angle and the traveling speed between the input shaft 2a and the output shaft 2b. . Therefore, since the torque can be continuously changed in proportion to the torque of the steering wheel 1 applied to the steering shaft 2 while the steering shaft 2 is rotated, steering of the steering apparatus is made very smooth.

Figure 10a is a graph showing the steering force change of the electric power steering apparatus equipped with a steering torque detection device according to the present invention, Figure 10b is an electric power by the steering torque detection device according to the present invention added a speed-sensitive speed variable resistance This graph shows the change in steering power when the driving speed of the steering system increases.

As shown in FIG. 10A, a power steering apparatus employing a steering torque detection device according to an embodiment of the present invention includes a torsion angle of a steering shaft 2 (a torsion angle with respect to an output shaft 2b of the input shaft 2a). That is, it is possible to generate a steering force smoothly variable according to the torque change of the steering shaft (2) can greatly improve the steering feeling. In addition, as shown in Figure 10b, when the running speed of the vehicle increases the steering force is reduced by the action of the speed variable resistor 10 to prevent the steering wheel (1) from being lighter at high speed.

Such a steering torque detection device for an electric power steering apparatus according to an embodiment of the present invention controls the driving of the driving unit 5 without a separate calculation circuit, thereby fundamentally eliminating the possibility of malfunction due to arithmetic errors, and the safety of the steering device. It can increase dramatically. In addition, the configuration is very simple, there is an advantage that the manufacturing cost is inexpensive, it can greatly contribute to the weight reduction of the vehicle.

Meanwhile, FIG. 5 illustrates a steering torque detection device for an electric power steering apparatus according to another embodiment of the present invention.

The steering torque detection device for the electric power steering apparatus is, unlike one embodiment, an electric power steering apparatus including an electric motor in which a driving unit rotates in only one direction (the power steering apparatus of the present patent application No. 1998-076895) And the left and right light emitting elements 35 and 36, the variable resistance means 3 being spaced apart from each other in the rotational direction of the input shaft 2a on the input shaft 2a of the steering shaft 2, A light control non-contact steering torque detection device comprising a light receiving element 37 provided at an output shaft 2b at a position corresponding to the center between the left and right light emitting elements 35 and 36. And, the direction control means 6, the drive unit 5 is made of an electric motor that rotates in only one direction, unlike the steering apparatus of an embodiment, so that the forward and reverse rotation direction to the steering shaft (2) by selecting The tack switch 41 may operate the transmission part 60 having the forward / reverse rotation parts 60a and 60b to transmit and the forward / reverse rotation parts 60a and 60b of the transmission part 60. And electronic clutches 61 which are controlled by applying the power of 42.

The left and right light emitting devices 35 and 36 are respectively installed in the input shaft 2a and irradiate light through the exit holes 35a and 36a having a predetermined inner diameter. The light receiving element 37 is installed in the incident hole 37a of the predetermined inner diameter of the output shaft 2b, and detects light introduced through the incident hole 37a to the power applied to the amplifier 7. And induce a resistance inversely proportional to the amount of received light. And when the amount of received light is zero, it is configured to completely cut off the power applied to the amplifier 7 with infinite resistance.

Then, the direction control means 6, the drive unit 5 outputs only the rotational force in one direction, so that the transmission unit having a forward / reverse rotation unit 60a, 60b that can change the rotation direction of the drive unit 5 (傳動 部) (60) and electromagnetic clutches 61 for controlling the operation of the forward / reverse rotation parts 60a and 60b of the transmission part 60 by applying power to the tack switches 41 and 42 ( See FIG. 1). In this configuration, the direction control means (6) is a power source applied by the left and right switches (41, 42), which is the steering direction detection means (4), the electric clutch 61 is connected to the drive unit (5) The torque direction of the drive unit 5 added to the steering shaft 2 is controlled by selectively connecting the forward rotation unit 60a or the reverse rotation unit 60b of the 60 to the steering shaft 2.

According to such a configuration, the variable resistance means 3 including the left and right light emitting elements 35 and 36 and one light receiving element 37 has the same function as the variable resistance means 3 of the above-described embodiment. When the steering wheel 1 is in a neutral position, that is, the steering shaft 2 is in a straight position, there is no overlapping section between the exit holes 35a and 36a and the entrance hole 37a, so that the light receiving amount of the light receiving element 37 is zero. Therefore, the light receiving element 37 cuts off the power supply of the amplifier 7 with infinite resistance. Then, when the input shaft (2a) is rotated by the steering wheel (1), the overlap section of the exit hole (35a, 36a) and the incident hole (3a) is generated, the light of the light emitting element (35, 36) is received Incident on (37), the light receiving element 37 induces a resistance having a magnitude inversely proportional to the amount of received light and applies it to a power source applied to the amplifier 7. At the same time, when the steering direction detecting means 4 detects the steering direction by the left and right switches 41 and 42 operated by the knob 40, the direction control means 6 causes the left and right switches 41 to be detected. The electronic clutch 61 is operated by the power applied through any one of 42, and one of the forward rotation unit 60a and the reverse rotation unit 60b of the transmission unit 60 is selected to the steering shaft 2. By connecting, the torque direction of the drive part 5 added to the steering shaft 2 is determined. Accordingly, the driving unit 5 outputs torque of a magnitude proportional to the rotation angle of the input shaft 2a by the power applied from the amplifier 7, and passes through the direction control means 6 to the steering shaft 2 to the steering shaft 2. It is added in the rotation direction of 2). The operation and effects thereof of the steering torque detection device according to another embodiment of the present invention which operates as described above are the same as those of the foregoing embodiment, and thus a detailed description thereof will be omitted.

On the other hand, the resistance and current of the power applied to the amplifier 7 through the variable resistance means 3 of the light control method is changed as shown in the graphs shown in Figs. 6 and 7 according to the rotational displacement of the input shaft 2a, The output of the driver 5 driven by the power amplified by the amplifier 7 is changed as shown in the graph of FIG.

According to the steering torque detection device for an electric power steering apparatus according to the present invention as described in detail above, the torque of the steering wheel applied to the steering shaft through a variable resistance that is elaborately variable according to the relative rotation displacement of the input shaft and the output shaft of the steering shaft. By amplifying a proportional power source and applying it to the driving unit, the driving unit can add torque to the steering shaft as an output that is sensitively changed analogously according to a change in the torsion angle of the input shaft. Therefore, the electric motor of the steering apparatus can add a torque that is continuously variable in proportion to the torque of the steering wheel applied to the steering shaft with respect to the steering shaft, thereby improving the steering feeling of the steering apparatus.

In addition, since the steering torque detection device for the electric power steering apparatus according to the present invention controls the driving of the driving unit without a separate calculation circuit, it is possible to fundamentally eliminate the possibility of malfunction due to a calculation error, thereby greatly increasing the safety of the steering device.

In addition, the configuration is very simple, and the manufacturing cost is low, it can greatly contribute to the weight reduction of the vehicle.

Claims (6)

It is installed on the power circuit of the drive unit for adding torque to the steering shaft consisting of an input shaft on which the steering wheel is mounted and an output shaft coupled to the input shaft by means of elastic means so as to connect the input shaft in a relative rotational displacement with respect to the steering link. Variable resistance means each provided on the input shaft and the output shaft and short-circuited by a torsion between the input shaft and the output shaft, and for applying a resistance in inverse proportion to the relative rotational displacement amount; Steering direction sensing means for sensing a relative rotational direction of the input shaft relative to the output shaft; Direction control means for controlling an output direction of the driving unit by a signal of the steering direction detecting means; And an amplifier for amplifying the power applied by the short circuit of the variable resistance means and applying the amplified power to the drive unit. The method of claim 1, The variable resistance means Left and right variable resistors installed on the output shaft of the steering shaft and spaced apart in the rotational direction of the output shaft, the left and right variable resistors having lengths in the rotational direction and connected to the amplifying units, respectively; A contactor installed on an input shaft at a position corresponding to a center between the left and right variable resistors to selectively contact the left and right variable resistors according to rotation of the input shaft to short-circuit a power supply, Steering torque detection device for an electric power steering device, characterized in that configured to vary the resistance in accordance with the contact position of the contact with the variable resistor. The method of claim 1, The variable resistance means Left and right light emitting devices installed in the left and right exit holes spaced apart from each other in an input shaft of the steering shaft in a rotational direction of the input shaft; The left and right projected through the left and right exit hole installed in the entrance hole formed on the output shaft of the position corresponding to the center between the left and right exit hole, and selectively overlaps the entrance hole with the rotation of the input shaft. A steering torque detection device for an electric power steering apparatus, comprising: a light receiving element for shorting the power by light of the light emitting element and inducing a resistance inversely proportional to the amount of light received. The method according to any one of claims 1 to 3, And a speed variable resistor which adds a resistance proportional to the traveling speed with respect to the power applied by the variable resistance means and input to the amplifying unit. The method according to any one of claims 1 to 3, The steering direction detection means, The left and right switches are provided on the output shaft spaced apart in the rotational direction of the output shaft and selectively operated by a knob mounted to the input shaft and rotated together with the input shaft, thereby providing a signal to the direction control means. Steering torque detection device for an electric power steering device comprising a. The method of claim 5, The direction control means, An electric motor having a forward / reverse rotation part configured to transfer the power of the driving part to the steering shaft by a power applied through the left and right switches, and to forward and reverse rotation directions; A steering torque detection device for an electric power steering apparatus, characterized in that it is formed as an electromagnetic clutch for controlling the operation of the forward / reverse rotation part of the electric drive by applying power to the left and right switches.