JP2017019443A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering device capable of suppressing deterioration in detection accuracy of a steering angle.SOLUTION: A steering device includes: a rack shaft 13 interlocking with a steering wheel 10; and a turning motor 30 for driving the rack shaft 13. The steering device includes: a reduction gear 23 which transmits rotation of the turning motor 30 to the rack shaft 13 via a belt 26 and reduces speed of the rotation of the turning motor 30; a tension applying pulley 33 which applies tension to the belt 26 and is rotated by interlocks with the belt 26. The steering device includes: a first relative angle sensor 32 for detecting a relative rotation angle of the turning motor 30; a second relative angle sensor 34 for detecting a relative rotation angle of the tension applying pulley 33; and an ECU for controlling driving of the turning motor 30. The ECU calculates an absolute rotation angle of the turning motor 30 on the basis of a first relative rotation angle detected through the first relative angle sensor 32 and a second relative rotation angle detected through the second relative angle sensor 34.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steering apparatus.

  As a vehicle steering apparatus, a steer-by-wire in which a steering wheel and a steered wheel are mechanically separated is known. Some of such steering devices are provided with a clutch for intermittently transmitting power from a steering wheel to a steered wheel (see, for example, Patent Document 1).

  The steering device described in Patent Literature 1 includes a reaction force motor that applies a steering reaction force to the steering wheel side, and a drive motor that applies a steering force to the steered wheels. Further, the steering device is provided with a steering angle sensor that detects the steering angle (absolute angle) of the steering wheel, a steering torque sensor that detects the steering torque, and the like. The control device of the steering device drives the reaction force motor according to the steering torque or the like to apply the reaction force to the steering wheel, and drives the drive motor in accordance with the steering to perform the turning operation.

JP 2011-5933 A

  Incidentally, the steering angle sensor provided in the steering apparatus as described above is provided between the steering wheel and the torque sensor in the steering shaft. For this reason, there is a possibility that the detection accuracy of the steering angle may be lowered due to play or attachment tolerance for mounting the steering angle sensor on the steering shaft. In addition, the same thing may be concerned not only in steer-by-wire but also in a steering device in which the steering wheel and the steered wheel are not mechanically separated.

  An object of the present invention is to provide a steering device capable of suppressing a decrease in steering angle detection accuracy.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A steering device that solves the above problems includes a shaft that is linked to a steering wheel, a motor that generates a driving force applied to the shaft, and the rotation of the motor is transmitted to the shaft via a belt. A speed reducer that reduces the rotation, a rotating body that applies tension to the belt and rotates in conjunction with the belt, a motor relative angle sensor that detects a relative rotation angle of the motor, and a relative rotation of the rotating body A rotating body relative angle sensor that detects an angle; and a control unit that controls driving of the motor, wherein the control unit detects a motor relative rotation angle detected through the motor relative angle sensor and the rotating body relative angle sensor. The gist is to calculate the absolute rotation angle of the motor based on the relative rotation angle of the rotating body detected through

  According to the above configuration, the absolute rotation angle of the motor can be calculated using the relative rotation angle of the motor and the relative rotation angle of the rotating body, and eventually the absolute rotation angle of the steering wheel that is linked to the motor via the shaft ( Steering angle) can be calculated. Therefore, the steering angle can be calculated without providing a rotation angle sensor below the steering wheel, and a decrease in the detection accuracy of the steering angle can be suppressed.

In the steering apparatus, it is preferable that the motor includes a motor housing, and the rotating body is rotatably provided on the motor housing.
According to the said structure, the rotary body which provides tension | tensile_strength to a belt is rotatably provided in a motor housing. Thereby, the tension | tensile_strength of the belt by a rotary body can be adjusted by adjusting a motor housing, without adjusting a rotary body directly. For this reason, the adjustment work of the belt tension can be simplified.

  In the steering apparatus, the shaft is a rack shaft that turns the steered wheels by reciprocating in conjunction with the steering wheel, and the motor generates a driving force applied to the rack shaft. It is a rudder motor, It is preferable that the said control part calculates the absolute rotation angle of the said steering motor based on the said motor relative rotation angle and the said rotary body relative rotation angle.

  According to the above configuration, the absolute rotation angle of the steered motor can be calculated using the relative rotation angle of the steered motor that drives the rack shaft and the relative rotational angle of the rotating body. The absolute rotation angle (steering angle) of the steering wheel interlocked with the rudder motor can be calculated.

  A driving force is applied to the steering device, the steering mechanism including the steering wheel, the steering shaft as the shaft, and the reaction force motor as the motor that generates the steering reaction force applied to the steering shaft. Between the steering mechanism and the steering mechanism, and a steering mechanism having a steering shaft for turning the steered wheels by reciprocating and a steering motor for generating a driving force applied to the steering shaft. And a mechanically interrupted clutch.

  According to the above configuration, even in the steer-by-wire in which the steering mechanism and the steering mechanism are mechanically separated, the steering angle can be calculated without providing the steering angle sensor below the steering wheel. For this reason, the fall of the detection accuracy of a steering angle can be suppressed. Further, the maintenance accuracy of the steering control based on the steering angle can be maintained and improved.

  In the steering apparatus, the shaft is a steering shaft fixed to the steering wheel, the motor is an assist motor that generates an assist force applied to the steering shaft, and the control unit The absolute rotation angle of the assist motor is preferably calculated based on the motor relative rotation angle and the rotating body relative rotation angle.

  According to the above configuration, the absolute rotation angle of the assist motor can be calculated using the relative rotation angle of the assist motor that drives the steering shaft and the relative rotation angle of the rotating body. The absolute rotation angle (steering angle) of the interlocking steering wheel can be calculated.

  According to the present invention, it is possible to suppress a decrease in detection accuracy of the steering angle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified diagram showing a schematic configuration of a steering apparatus according to a first embodiment. The side view which shows the reduction gear of the assist mechanism of the steering apparatus of the embodiment. The block diagram which shows the electric constitution of the steering device of the embodiment. 3 is a graph showing two types of relative rotation angles detected by a plurality of relative angle sensors provided in the steering apparatus of the embodiment and an angle difference between these relative rotation angles. The simplification figure which shows schematic structure of the steering apparatus of 2nd Embodiment. The block diagram which shows the electric constitution of the steering device of the embodiment.

(First embodiment)
Hereinafter, a first embodiment of the steering apparatus will be described. The steering device is a so-called rack parallel type electric power steering device (RP-EPS).

  As shown in FIG. 1, the steering apparatus includes a steering wheel 10 operated by a driver and a steering shaft 11 fixed to the steering wheel 10. A pinion shaft 12 is provided at the end of the steering shaft 11 opposite to the steering wheel 10. A pinion gear 12 a provided on the pinion shaft 12 is meshed with a rack gear 14 provided on the rack shaft 13. The rotational motion of the pinion shaft 12 is converted into a reciprocating linear motion in the axial direction of the rack shaft 13 via the pinion gear 12 a and the rack gear 14. The reciprocating linear motion is transmitted to the left and right steered wheels 16 and 16 via tie rods 15 and 15 respectively connected to both ends of the rack shaft 13, whereby the steered angles of the steered wheels 16 and 16 are changed. The A torque sensor 19 is provided on the steering shaft 11. The torque sensor 19 detects a steering torque applied to the steering shaft 11. The steering wheel 10 and the steering shaft 11 constitute a steering mechanism. The pinion shaft 12, the rack shaft 13, and the rack gear 14 constitute a steering mechanism.

  The steering apparatus includes an assist mechanism 20 that assists the driver's steering operation. The assist mechanism 20 transmits to the ball screw mechanism 21 a turning motor 30 that is a source of assist force, a ball screw mechanism 21 attached to the rack shaft 13, and the rotational force of the rotating shaft 30 c of the steering motor 30. A reduction gear 23 is provided. The assist mechanism 20 converts the rotational force of the rotating shaft 30c of the steered motor 30 into a reciprocating linear motion in the axial direction of the rack shaft 13 via the speed reducer 23 and the ball screw mechanism 21, thereby allowing the driver to perform the steering operation. Assist. Here, the rack shaft 13 corresponds to a shaft.

  The pinion shaft 12, the rack shaft 13, and the assist mechanism 20 are accommodated in the rack housing 17. The rack housing 17 is provided with a reduction gear housing 18 that houses a part of the reduction gear 23. The reduction gear housing 18 protrudes in an intersecting direction (downward in the drawing) with respect to the direction in which the rack shaft 13 extends. A steered motor 30 is fixed to the outer wall of the reducer housing 18 (the right portion in the figure). The steered motor 30 has a motor housing 31. The motor housing 31 is fixed to the reduction gear housing 18 with bolts or the like. A cylindrical stator 30 b is attached to the inner peripheral wall of the motor housing 31. In the motor housing 31, a rotor 30a is provided inside the stator 30b. A gap is provided between the circumferential surface of the rotor 30a and the stator 30b. A rotary shaft 30c passes through the rotor 30a. The rotating shaft 30c is disposed so as to be parallel to the direction in which the rack shaft 13 extends. The rotating shaft 30 c of the steered motor 30 extends through the motor housing 31 into the reduction gear housing 18. The rotary shaft 30 c is pivotally supported by the motor housing 31. In a state where the bolt that fixes the motor housing 31 to the speed reducer housing 18 is loosened, the motor housing 31 is rotatable about the rotation shaft 30c of the steered motor 30 as a rotation center. In the reduction gear housing 18, the bolt moves along a long hole provided in a portion where the motor housing 31 is fixed.

The ball screw mechanism 21 has a nut 22 that is screwed into a ball screw groove provided on the rack shaft 13 via balls as a number of rolling elements.
The speed reducer 23 includes a drive pulley 24 that is integrally attached to the rotating shaft 30 c of the steering motor 30, a driven pulley 25 that is integrally attached to the outer periphery of the nut 22 of the ball screw mechanism 21, and a drive pulley 24. A belt 26 wound around the driven pulley 25 is provided. For example, a toothed belt is employed as the belt 26.

  Teeth are provided on the outer periphery of the drive pulley 24 at equal intervals. The number of teeth of the drive pulley 24 is 43, for example. Teeth are provided at equal intervals on the outer periphery of the driven pulley 25. The number of teeth of the driven pulley 25 is set to be larger than the number of teeth of the drive pulley 24. The number of teeth of the driven pulley 25 is 133, for example. A tension applying pulley 33 is rotatably provided on a side wall fixed to the motor housing 31, more precisely, the speed reducer housing 18. The tension applying pulley 33 meshes with the teeth of the belt 26 and applies tension to the belt 26. Teeth are provided on the outer periphery of the tension applying pulley 33 at equal intervals. The number of teeth of the tension applying pulley 33 is, for example, 38.

  The rotation shaft 33a of the tension applying pulley 33 is provided so as to be parallel to the direction in which the rotation shaft 30c of the steering motor 30 extends. The rotating shaft 30 c extends so as to penetrate the inside and outside of the motor housing 31. A rotation shaft 33 a of the tension applying pulley 33 is supported by the motor housing 31. The tension applying pulley 33 corresponds to a rotating body.

  The steered motor 30 is provided with a first relative angle sensor 32 that detects a first relative rotational angle θ <b> 1 that is the rotational angle of the rotating shaft 30 c of the steered motor 30. The rotation shaft 33a of the tension applying pulley 33 is provided with a second relative angle sensor 34 that detects a second relative rotation angle θ2 that is the rotation angle of the rotation shaft 33a of the tension applying pulley 33. The first relative angle sensor 32 corresponds to a motor relative angle sensor, and the first relative rotation angle θ1 corresponds to a motor relative rotation angle. The second relative angle sensor 34 corresponds to a rotating body relative angle sensor, and the second relative rotation angle θ2 corresponds to a rotating body relative rotation angle.

  As the first relative angle sensor 32 and the second relative angle sensor 34, MR sensors 32b and 34b are employed, respectively. The MR sensors 32b and 34b detect magnetic fields generated from the magnets 32a and 34a attached to the base ends of the rotary shafts 30c and 33a. The MR sensors 32b and 34b generate two analog signals, a sin signal and a cos signal, according to the magnetic field that changes as the rotating shafts 30c and 33a rotate. The MR sensors 32b and 34b are respectively provided on the substrate.

  As shown in FIG. 2, when the speed reducer 23 is viewed from the direction in which the rotating shaft 30 c of the steered motor 30 extends, the tension applying pulley 33 is between the drive pulley 24 and the driven pulley 25 and is an annular belt. 26 is located inside. Tension is applied by bringing the tension applying pulley 33 into contact with the belt 26 from the inside to the outside. In addition, as indicated by an arrow in FIG. 2, the motor housing 31 is rotated about the rotation shaft 30 c of the steered motor 30 as the center of rotation in a state where the bolt that fixes the motor housing 31 to the reduction gear housing 18 is loosened. Thus, the contact force of the tension applying pulley 33 with respect to the belt 26 is changed. It is possible to adjust the tension of the belt 26 through the change of the contact force.

As shown in FIG. 3, the steering device includes an ECU 40 that controls the steered motor 30. The ECU 40 functions as a control unit of the steering device.
The ECU 40 determines the steering angle (absolutely the rotation angle of the steering shaft 11 based on the first relative rotation angle θ1 detected through the first relative angle sensor 32 and the second relative rotation angle θ2 detected through the second relative angle sensor 34). Rotation angle) is calculated. That is, since the steering angle corresponds to the absolute rotation angle of the rotation shaft 30c of the steering motor 30, the steering angle can be calculated based on the first relative rotation angle θ1 and the second relative rotation angle θ2. The ECU 40 controls the steered motor 30 based on the absolute rotation angle of the steered motor 30. In FIG. 3, for convenience of explanation, a sign “θ1” indicating the first relative rotation angle is attached to the output from the first relative angle sensor 32 and the output from the second relative angle sensor 34 is the second relative rotation angle. The symbol “θ2” is attached.

Next, a method for calculating the absolute rotation angle by the ECU 40 will be described.
The ECU 40 calculates the first relative rotation angle θ1 by obtaining the arc tangent from the two analog signals acquired from the first relative angle sensor 32. The ECU 40 calculates the second relative rotation angle θ2 by obtaining the arc tangent from the two analog signals acquired from the second relative angle sensor 34.

  The vertical axis of the graph shown in FIG. 4 indicates the first relative rotation angle θ1 and the second relative rotation angle θ2, and the horizontal axis indicates the multiple rotation absolute rotation angle φ of the steering shaft 11. The broken line indicates the transition of the first relative rotation angle θ1, and the solid line indicates the transition of the second relative rotation angle θ2. Note that the output signal of the first relative angle sensor 32 has a shaft double angle of 1 and the output signal of the second relative angle sensor 34 has a shaft double angle of 2 times. Then, due to the difference in the reduction ratio between the steered motor 30 and the tension applying pulley 33, the phase of the solid waveform and the phase of the broken waveform shift with rotation. The first relative rotation angle θ1 and the second relative rotation angle θ2 are rotation angles (0 ° to 360 °) in the detection range of the MR sensor, respectively. That is, from each of the first relative rotation angle θ1 and the second relative rotation angle θ2, it is not possible to calculate the absolute rotation angle φ, which is the multiple rotation angle of the steering shaft 11.

  Therefore, the ECU 40 calculates an angle difference (| θ1-θ2 |) between the first relative rotation angle θ1 and the second relative rotation angle θ2. The thick line in the graph of FIG. 4 indicates the angle difference. As shown in FIG. 4, as the absolute rotation angle φ increases, the angle difference (| θ1−θ2 |) increases in proportion to the absolute rotation angle φ. For this reason, the ECU 40 can calculate the absolute rotation angle φ from the angle difference (| θ1-θ2 |) by grasping in advance the absolute rotation angle φ with respect to the angle difference (| θ1-θ2 |). The ECU 40 has a memory 41. The memory 41 stores in advance an absolute rotation angle φ with respect to the angle difference (| θ1−θ2 |).

Next, the operation of the steering device configured as described above will be described.
The ECU 40 calculates a target assist torque based on the steering torque. The ECU 40 drives and controls the steering motor 30 so that the assist torque applied to the steering shaft 11 becomes the target assist torque. Further, the ECU 40 calculates the steering angle (absolute rotation angle φ) of the steering wheel 10 when the vehicle is powered on. The ECU 40 calculates the absolute rotation angle φ using the first relative rotation angle θ1 and the second relative rotation angle θ2 obtained from the first relative angle sensor 32 and the second relative angle sensor 34.

  According to the steering apparatus as described above, the absolute rotation angle φ can be calculated from the first relative rotation angle θ1 and the second relative rotation angle θ2 obtained from the first relative angle sensor 32 and the second relative angle sensor 34. Therefore, it is possible to suppress a decrease in detection accuracy of the steering angle.

As described above, according to this embodiment, the following effects can be obtained.
(1) The absolute rotational angle of the steered motor 30 can be calculated using the first relative rotational angle θ1 of the steered motor 30 and the second relative rotational angle θ2 of the tension applying pulley 33. Thus, the absolute rotation angle (steering angle) of the steering wheel 10 linked to the steering motor 30 can be calculated. For this reason, a steering angle can be calculated without providing a rotation angle sensor in the lower part of the steering wheel 10, and the fall of the detection accuracy of a steering angle can be suppressed.

  (2) A rotating body that applies tension to the belt 26 is rotatably provided in the motor housing 31. Accordingly, the tension of the belt 26 by the tension applying pulley 33 can be adjusted by adjusting the position of the motor housing 31 with respect to the speed reducer housing 18 without directly adjusting the tension applying pulley 33. For this reason, the adjustment work of the tension of the belt 26 can be simplified.

(Second Embodiment)
Hereinafter, a second embodiment of the steering device will be described with reference to FIGS. 5 and 6. The steering apparatus of this embodiment is different from the first embodiment in that the steering mechanism and the steering mechanism are steer-by-wires that are mechanically separated. Hereinafter, a description will be given focusing on differences from the first embodiment.

  As shown in FIG. 5, the steering device includes a clutch 45 that mechanically connects and disconnects between the steering mechanism and the steering mechanism. The clutch 45 is provided on the steering shaft 11. The clutch 45 is disconnected when power is supplied from the ECU 40 and is connected when power supply from the ECU 40 is stopped. When the clutch 45 is disconnected, the steering wheel 10 and the steered wheel 16 are mechanically separated. When the clutch 45 is connected, the steering wheel 10 and the steered wheel 16 are mechanically coupled.

An absolute angle sensor 46 that detects an absolute rotation angle of the steering shaft 11 is provided on the rack shaft 13 side of the clutch 45 of the steering shaft 11.
The steering device includes a reaction force motor 50 that applies a steering reaction force to the steering shaft 11. The reaction motor 50 has a motor housing 51. A cylindrical stator 50 b is attached to the inner peripheral wall of the motor housing 51. Inside the motor housing 51, a rotor 50a is provided inside the stator 50b. A gap is provided between the peripheral surface of the rotor 50a and the stator 50b. A rotation shaft 50c passes through the rotor 50a. The rotating shaft 50c is arranged so as to be parallel to the direction in which the steering shaft 11 extends. A rotating shaft 50 c of the reaction force motor 50 is pivotally supported by the motor housing 51. The reaction force motor 50 is connected to the steering shaft 11 via a speed reducer.

  A drive pulley 52 is fixed to the rotating shaft 50 c of the reaction force motor 50. Teeth are provided at equal intervals on the outer periphery of the drive pulley 52. The number of teeth of the drive pulley 52 is 43, for example. A driven pulley 53 is fixed to an intermediate portion of the steering shaft 11. Teeth are provided on the outer periphery of the driven pulley 53 at equal intervals. The number of teeth of the driven pulley 53 is 133, for example.

  A belt 54 is wound between the driving pulley 52 and the driven pulley 53. The driving pulley 52, the driven pulley 53, and the belt 54 function as a speed reducer. The driving force of the reaction force motor 50 is applied to the steering shaft 11 via a reduction gear. Here, the steering shaft 11 corresponds to a shaft.

  The motor housing 51 is rotatably provided with a tension applying pulley 56 that meshes with the teeth of the belt 54 and applies tension to the belt 54. Teeth are provided on the outer periphery of the tension applying pulley 56 at equal intervals. The number of teeth of the tension applying pulley 56 is, for example, 38.

  The rotating shaft 56a of the tension applying pulley 56 is provided so as to be parallel to the direction in which the rotating shaft 50c of the reaction force motor 50 extends. The rotating shaft 50 c extends so as to penetrate the inside and outside of the motor housing 51. A rotation shaft 56 a of the tension applying pulley 56 is supported by the motor housing 51. The tension applying pulley 33 corresponds to a rotating body. In FIG. 5, the motor housing 51 and the like are illustrated in a simplified manner.

  The reaction force motor 50 is provided with a third relative angle sensor 55 that detects a third relative rotation angle θ3 that is a relative rotation angle of the rotation shaft 50c of the reaction force motor 50. The tension applying pulley 56 is provided with a fourth relative angle sensor 57 that detects a fourth relative rotation angle θ4 that is a rotation angle of the rotation shaft 56a of the first tension applying pulley 56. The third relative angle sensor 55 corresponds to a motor relative angle sensor, and the third relative rotation angle θ3 corresponds to a motor relative rotation angle. The fourth relative angle sensor 57 corresponds to a rotating body relative angle sensor, and the fourth relative rotation angle θ4 corresponds to a rotating body relative rotation angle.

  MR sensors 55b and 57b are employed as the third relative angle sensor 55 and the fourth relative angle sensor 57, respectively. The MR sensors 55b and 57b detect magnetic fields generated from the magnets 55a and 57a attached to the base ends of the rotation shafts 50c and 56a. The MR sensors 55b and 57b generate two analog signals, a sin signal and a cos signal, in accordance with a magnetic field that changes as the rotating shafts 50c and 56a rotate.

  The steering device includes a rack drive mechanism 60 that steers the steered wheels 16 according to the steering of the driver. The rack drive mechanism 60 includes a turning motor 61 that is a source of turning force, a speed reducer (for example, a worm speed reducer) 63 that reduces the rotation of the turning motor 61, and a second pinion shaft that is meshed with the rack shaft 13. 65. The second pinion shaft 65 has a second pinion gear 65 a that meshes with a second rack gear 66 provided on the rack shaft 13. The rotational motion of the second pinion shaft 65 is converted into a reciprocating linear motion in the axial direction of the rack shaft 13 via the second pinion gear 65a and the second rack gear 66. The rack drive mechanism 60 constitutes a turning mechanism together with the pinion shaft 12, the rack shaft 13, and the rack gear 14.

  The turning motor 61 is provided with a fifth relative angle sensor 62 that detects the rotation angle of the rotation shaft of the turning motor 61. An MR sensor is employed as the fifth relative angle sensor 62.

  The speed reducer 63 has a worm 61a provided on the rotating shaft of the steering motor 61, and a worm wheel 63a with which the worm 61a meshes. A second pinion shaft 65 is fixed to the worm wheel 63a.

As shown in FIG. 6, the steering device includes an ECU 40 that controls the reaction force motor 50 and the steered motor 61. The ECU 40 functions as a control unit of the steering device.
The ECU 40 determines the steering angle (absolutely the rotation angle of the steering shaft 11) based on the third relative rotation angle θ3 detected through the third relative angle sensor 55 and the fourth relative rotation angle θ4 detected through the fourth relative angle sensor 57. Rotation angle) is calculated. The ECU 40 controls the reaction force motor 50 based on the absolute rotation angle. In FIG. 6, for convenience of explanation, a sign “θ3” indicating the third relative rotation angle is attached to the output from the third relative angle sensor 55 and the output from the fourth relative angle sensor 57 is the fourth relative rotation angle. The symbol “θ4” is attached.

  As shown in FIG. 6, the ECU 40 steers the steered wheels 16 in accordance with the steering of the steering wheel 10 while performing feedback control according to the absolute rotation angle on the steered side of the steering shaft 11 obtained from the absolute angle sensor 46. The steered motor 61 is driven and controlled as described above. The ECU 40 calculates a steering angle based on the third relative rotation angle θ3 and the fourth relative rotation angle θ4 detected through the third relative angle sensor 55 and the fourth relative angle sensor 57, and the steered wheels 16 based on the steering angle. The target turning angle is calculated. Then, the ECU 40 controls the steered motor 61 so that the actual steered angle detected based on the rotational angle of the steered motor 61 matches the target steered angle. Note that the steered wheels 16 may be steered by the amount that the steering wheel 10 is operated. At this time, the ECU 40 controls the steered motor 61 so that the actual steered angle matches the steering angle.

  The ECU 40 executes reaction force control that generates a steering reaction force according to the steering torque through drive control of the reaction force motor 50. That is, the ECU 40 calculates a target steering reaction force (target reaction force torque) based on the steering torque detected through the torque sensor 19. The ECU 40 controls the reaction force motor 50 so that the actual steering reaction force (reaction torque) applied to the steering shaft 11 matches the target steering reaction force.

Next, the operation of the steering device configured as described above will be described.
When the clutch 45 is disengaged and the steering device functions as a steer-by-wire, the ECU 40 applies a steering reaction force by the reaction force motor 50 to the steering by the driver, and the rack drive mechanism according to the driver's steering. The 60 steered motors 61 are driven to steer the steered wheels 16.

  That is, when the power of the vehicle is turned on, the ECU 40 steers the steering wheel 10 from the third relative rotation angle θ3 and the fourth relative rotation angle θ4 obtained from the third relative angle sensor 55 and the fourth relative angle sensor 57. An angle (absolute rotation angle φ) is calculated. Then, the ECU 40 drives and controls the steering motor 61 so that the steering corresponding to the absolute rotation angle φ of the steering shaft 11 is performed. Further, the ECU 40 controls the reaction force motor 50 so that the actual reaction force torque applied to the steering shaft 11 matches the target reaction force torque.

  Thus, when the steering device functions as a steer-by-wire, the power transmission path between the steering mechanism and the steered mechanism is mechanically disconnected by the clutch 45, so that vibrations from the steered wheels 16 are not affected by the steering wheel 10. It is suppressed that it is transmitted to. Since the steered wheels 16 are steered according to the operation of the steering wheel 10, the driver can perform comfortable steering.

  When an abnormality occurs in the steered motor 61, the ECU 40 mechanically connects the steering mechanism and the steered mechanism by connecting the clutch 45, and directly transmits the rotation of the steering shaft 11 to the steered wheels 16. It is possible to do. The ECU 40 applies an assist force to the steering shaft 11 by drivingly controlling the reaction force motor 50 according to the steering torque. Thus, the steering force is applied to the steering shaft 11 to assist the driver's steering.

As described above, according to the present embodiment, in addition to the effect (2) of the first embodiment, the following effects can be achieved.
(3) The absolute rotation angle of the reaction force motor 50 can be calculated using the third relative rotation angle θ3 of the reaction force motor 50 that drives the steering shaft 11 and the fourth relative rotation angle θ4 of the tension applying pulley 56. As a result, the absolute rotation angle (steering angle) of the steering wheel 10 interlocked with the reaction force motor 50 can be calculated via the steering shaft 11.

  (4) Even in a steer-by-wire where the steering mechanism and the steering mechanism are mechanically separated, the steering angle can be calculated without providing a steering angle sensor below the steering wheel 10. For this reason, the fall of the detection accuracy of a steering angle can be suppressed. Further, the maintenance accuracy of the steering control based on the steering angle can be maintained and improved.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, the output signal of the first relative angle sensor 32 is 1 × and the output signal of the second relative angle sensor 34 is 2 ×. However, the output signals of the first relative angle sensor 32 and the second relative angle sensor 34 may be a combination of arbitrary shaft angle multipliers. For example, the output signals of the first relative angle sensor 32 and the second relative angle sensor 34 may be the same shaft angle multiplier.

In the first embodiment, MR sensors are used as the first relative angle sensor 32 and the second relative angle sensor 34. However, a Hall sensor or a resolver may be used.
In the second embodiment, MR sensors are used as the third relative angle sensor 55 and the fourth relative angle sensor 57, but a Hall sensor or a resolver may be used.

  In each of the above embodiments, the tension applying pulleys 33 and 56 are positioned on the inner side of the annular belts 26 and 54 and brought into contact with the inner side, but the tension applying pulleys 33 and 56 are positioned on the outer side of the annular belts 26 and 54. It may be made to contact outside.

  In the above embodiments, the number of teeth of the driving pulleys 24, 52, the number of teeth of the driven pulleys 25, 53, and the number of teeth of the tension applying pulleys 33, 56 are arbitrarily set as long as the reduction ratio is maintained. Is possible.

  In the second embodiment, one ECU 40 controls the reaction force motor 50 and the steered motor 61. However, the reaction force motor 50 and the steered motor 61 may be provided integrally with each other.

  In each of the above embodiments, the tension applying pulleys 33 and 56 are provided in the motor housings 31 and 51. However, the tension applying pulleys 33 and 56 may be provided in other members. For example, in the first embodiment, the tension applying pulley 33 may be provided in the rack housing 17.

  In the second embodiment, the steer-by-wire steering device is used. However, the steer-by-wire configuration (the clutch 45, the absolute angle sensor 46, and the rack drive mechanism 60) may be omitted. That is, the present invention can be applied to a so-called column assist type electric power steering device (C-EPS) as a steering device. At this time, the reaction force motor 50 functions as an assist motor that assists steering. Even in this case, it is possible to suppress a decrease in the detection accuracy of the steering angle. Further, the maintenance accuracy of the steering control based on the steering angle can be maintained and improved.

  DESCRIPTION OF SYMBOLS 10 ... Steering wheel, 11 ... Steering shaft, 12 ... Pinion shaft, 12a ... Pinion gear, 13 ... Rack shaft, 14 ... Rack gear, 15 ... Tie rod, 16 ... Steering wheel, 17 ... Rack housing, 18 ... Reduction gear housing, 19 ... Torque sensor, 20 ... assist mechanism, 21 ... ball screw mechanism, 22 ... nut, 23 ... speed reducer, 24 ... drive pulley, 25 ... driven pulley, 26 ... belt, 30 ... steering motor, 30a ... rotor, 30b ... stator , 30c ... rotating shaft, 31 ... motor housing, 32 ... first relative angle sensor, 32a ... magnet, 32b ... MR sensor, 33 ... tension applying pulley, 33a ... rotating shaft, 34 ... second relative angle sensor, 34a ... magnet. 34b ... MR sensor, 40 ... ECU, 41 ... memory, 45 ... clutch, 46 ... absolute angle sensor 50, reaction force motor, 50a ... rotor, 50b ... stator, 50c ... rotating shaft, 51 ... motor housing, 52 ... driving pulley, 53 ... driven pulley, 54 ... belt, 55 ... third relative angle sensor, 55a ... Magnet 55b MR sensor 56 Tension pulley 56a Rotating shaft 57 Fourth relative angle sensor 57a Magnet 57b MR sensor 60 Rack drive mechanism 61 Steering motor 61a Warm 62 ... fifth relative angle sensor, 63 ... reduction gear, 63a ... worm wheel, 65 ... second pinion shaft, 65a ... pinion gear, 66 ... second rack gear, [theta] 1 ... first relative rotation angle, [theta] 2 ... second relative rotation. Angle, θ3: third relative rotation angle, θ4: fourth relative rotation angle, φ: absolute rotation angle.

Claims (5)

A shaft linked to the steering wheel,
A motor for generating a driving force applied to the shaft;
A reduction gear which transmits rotation of the motor to the shaft via a belt and decelerates rotation of the motor;
A rotating body that applies tension to the belt and rotates in conjunction with the belt;
A motor relative angle sensor for detecting a relative rotation angle of the motor;
A rotating body relative angle sensor for detecting a relative rotation angle of the rotating body;
A control unit for controlling the driving of the motor,
The controller calculates an absolute rotation angle of the motor based on a motor relative rotation angle detected through the motor relative angle sensor and a rotor relative rotation angle detected through the rotor relative angle sensor. apparatus. The motor includes a motor housing;
The steering device according to claim 1, wherein the rotating body is rotatably provided on the motor housing. The shaft is a rack shaft that steers steered wheels by reciprocating in conjunction with the steering wheel,
The motor is a steering motor that generates a driving force applied to the rack shaft,
The steering device according to claim 1, wherein the control unit calculates an absolute rotation angle of the steered motor based on the motor relative rotation angle and the rotating body relative rotation angle. A steering mechanism having the steering wheel, a steering shaft as the shaft, and a reaction force motor as the motor that generates a steering reaction force applied to the steering shaft;
A turning mechanism having a turning shaft that reciprocates by turning a driving force and turning a steered wheel, and a turning motor that generates a driving force applied to the turning shaft;
The steering apparatus according to claim 1, further comprising a clutch that mechanically interrupts between the steering mechanism and the steering mechanism. The shaft is a steering shaft fixed to the steering wheel,
The motor is an assist motor that generates an assist force applied to the steering shaft,
The steering device according to claim 1, wherein the control unit calculates an absolute rotation angle of the assist motor based on the motor relative rotation angle and the rotating body relative rotation angle.