KR100916174B1 - Steering device - Google Patents

Abstract

In the steering apparatus 200, the first motor 34a operates according to the steering operation of the steering wheel, the first steering shaft 52 steers one of the pair of wheels 58, and the first conversion unit Converts the rotational movement of the first rotor 31a, which is the rotational element of the first motor 34a, into the axial movement of the first steering shaft 52. The second motor 34b operates according to the steering operation of the steering wheel, the second steering shaft 53 steers the other of the pair of wheels 58, and the second conversion unit is the first motor 34b. The rotational motion of the first rotor 31b, which is the rotational element of, is converted into the axial motion of the second steering shaft 53. The connecting unit 60 connects the first rotor 31a and the second rotor 31b together and releases the connection of the first rotor 31a and the second rotor 31b.

Description

Steering Device {STEERING DEVICE}

The present invention relates to a general steering device, and more particularly to a steering device for steering a pair of wheels in accordance with the steering operation of the steering wheel by the driver.

The steering device of a vehicle generally includes a rack that is mechanically connected to a pair of right and left wheels using tie rods, steering arms and the like. When the steering wheel is rotated by the driver, the rack moves axially such that steering of the right and left wheels is performed in a manner integral with the movement of the rack.

Recently, a method of independently controlling and adjusting the right and left wheels has been proposed by separating the rack's mechanical connection from one of the right and left wheels.

For example, Japanese Patent Laid-Open No. 2003-0170849 discloses a vehicle steering apparatus including a plurality of steering actuators respectively provided on a plurality of wheels and a link member that cooperates with the plurality of wheels. In such steering apparatus, each steering of the plurality of wheels is independently controlled using a link member.

Further, Japanese Patent Laid-Open No. Hei 10-324523 discloses a vehicle steering angle changing device in which a rack can move laterally in accordance with a steering operation of a steering wheel, and a nut part and a screw part are provided between the rack and the wheel. This steering angle changing device changes the steering angle of the wheel in accordance with the steering operation by performing a telescopic movement by itself. By adopting such a steering apparatus, it is possible to perform steering control or adjustment in accordance with driving conditions of a vehicle such as turning speed.

For a steering apparatus that independently performs steering of each pair of wheels, it is required that steering of all wheels be safely and reliably performed even if an error occurs in the actuator steering one of the pair of wheels.

In this regard, Japanese Patent Laid-Open No. 10-324253 does not describe a method for reliably performing steering of all wheel pairs when a problem occurs in an actuator for steering one wheel.

In the steering apparatus of Japanese Patent Laid-Open No. 2003-170849, the operation of the other side steering actuator is transmitted through the link member so that steering of both wheels is performed when an abnormality occurs in one steering actuator. However, the steering apparatus of Japanese Patent Laid-Open No. 2003-170849 has a large load on the link member for connecting the pair of wheels to each other, and a large link member must be provided to cope with such a heavy load.

It is an object of the present invention to provide an improved steering apparatus which can solve the above problems.

It is still another object of the present invention to provide a steering apparatus which is compact in the structure in which steering of each of a pair of wheels is performed independently and which can reliably steer each of a pair of wheels.

In order to achieve the above object, the present invention,

A steering device for steering a pair of wheels in accordance with steering operation of a steering wheel,

A first motor operating in accordance with a steering operation of the steering handle;

A first steering shaft for steering one of the pair of wheels;

A first conversion unit for converting a relatively low torque rotational motion of the first rotor, which is a rotational element of the first motor, into a relatively high thrust axial motion of the first steering shaft;

A second motor operating in accordance with a steering operation of the steering handle;

A second steering shaft separated from the first steering shaft to steer the other of the pair of wheels;

A second conversion unit for converting a relatively low torque rotational motion of the second rotor, which is a rotational element of the second motor, into a relatively high thrust axial motion of the second steering shaft; And

It provides a steering apparatus including a connecting unit for connecting the first rotor and the second rotor together, and disconnecting the first rotor and the second rotor.

According to the steering apparatus of the present invention, it is possible to connect the first rotor and the second rotor of low torque, and to disconnect the first rotor and the second rotor. For this reason, when an abnormality occurs in the first motor or the second motor, the first rotor and the second rotor can be connected at a low load, and the first steering shaft and the second steering shaft can be interlocked. Therefore, it is possible to make the connection unit connecting the first rotor and the second rotor compact, and to provide a compact steering device capable of reliably steering a pair of wheels.

The steering apparatus of the present invention may be configured such that the connection unit includes a differential unit providing a differential action between the first rotor and the second rotor and a locking unit regulating the differential unit. According to the present invention, the differential action is regulated between the first rotor and the second rotor, the first rotor and the second rotor can be connected. By releasing the differential regulation, it is possible to disconnect the first rotor and the second rotor. For this reason, the use of a differential unit makes it possible to connect the first and second rotors at low loads. Therefore, a compact unit can also use a compact and can miniaturize the whole steering apparatus.

The steering apparatus of the present invention,

Differential unit

A first sun gear connected to the first rotor and rotatably supported;

A first internal gear rotatably supported and coaxial with the first sun gear;

A first planetary gear meshing with the first sun gear and the first internal gear;

A second sun gear connected to the second rotor and rotatably supported;

A second internal gear that is prevented from rotating and is disposed coaxially with the second sun gear; And

A second planetary gear meshed with the second sun gear and the second internal gear, rotatably connected to the first planetary gear, and coaxial with the first planetary gear;

With planetary gear mechanism to include,

The locking unit may be configured to regulate the rotational movement of the first internal gear to regulate the differential unit. According to the steering apparatus, the differential mechanism can be easily configured by using the planetary gear mechanism.

The steering apparatus of the present invention may be configured such that the differential unit includes a third motor for driving the first internal gear. According to the steering apparatus, since not only the first motor and the second motor but also the third motor can be used for steering control to achieve left and right independence, the load of the first motor and the second motor can be reduced.

The steering apparatus of the present invention has a torque transmission unit in which a locking unit is provided between the first internal gear and the third motor, which torque input unit transfers the input torque to the first internal gear when the input torque is given from the third motor. And, when given input torque from the second internal gear, prevent the input torque from being transmitted to the third motor and regulate the rotation of the second internal gear. According to the steering apparatus of the present invention, when driving the third motor, it is possible to give a differential action between the first rotor and the second rotor. If the third motor is not driven, the first rotor and the second rotor can be connected. For this reason, when connecting a 1st rotor and a 2nd rotor, abnormality in a locking unit can be prevented and reliability of a steering apparatus can be improved.

The steering apparatus of the present invention further includes a motor abnormality detecting unit for detecting an abnormality of any one of the first motor and the second motor, and the abnormality is found by both of the first motor and the second motor by the motor abnormality detecting unit. If not, the first rotor and the second rotor are disconnected, and when an abnormality is detected in at least one of the first motor and the second motor by the motor abnormality detection unit, the first rotor and the second rotor can be connected. The connection unit can be configured to be provided. According to the steering apparatus, even when an abnormality occurs in any one of the two motors, one of the pair of wheels can be properly steered.

The steering apparatus of the present invention may be configured such that when an abnormality is detected in one of the first motor and the second motor by the motor abnormality detecting unit, the other of the first motor and the second motor is operated according to the steering operation of the steering wheel. Can be. According to the steering apparatus, even when an abnormality occurs in the first motor or the second motor, the steering operation of the driver can be assisted by the operation of the other motor determined to be normal.

The steering apparatus of the present invention may be configured to further include a rotation angle sensing unit for detecting a difference between the rotation angle of the first motor and the rotation angle of the second motor, wherein the first rotor and the second rotor are connected by a connection unit. Before being connected together, it may be configured to drive the third motor so that the difference in rotation angle detected by the rotation angle sensing unit becomes zero. According to the steering apparatus, when an abnormality occurs in the first motor or the second motor, the first rotor and the second rotor can be connected in a state where the difference in rotation angle between them becomes zero. Thus, each of the pair of wheels can be steered at an appropriate steering angle.

The steering apparatus of the present invention has an input shaft connected to a steering handle, an output shaft connected to a first steering shaft or a second steering shaft through a steering gear, and a differential generating mechanism and a motor. And a transmission ratio changing device for activating and varying the transmission ratio between the input shaft and the output shaft. According to the steering device, a mechanical connection between the steering wheel, any one of the first steering shaft and the second steering shaft is possible through the input shaft and the output shaft. For this reason, a steering shaft with a mechanical connection can be reliably steered, and each of the pair of wheels can be reliably steered by the connection of the first and second steering shafts.

According to the present invention, in a configuration in which each of the pair of wheels can be independently steered, a compact steering device capable of reliably steering each of the pair of wheels is provided.

Other objects, features and advantages of the present invention will become apparent from the following embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the steering apparatus in one Embodiment of this invention.

2 is a flowchart for explaining the control process of the steering apparatus in the present embodiment.

3 is a configuration diagram of a steering apparatus in another embodiment of the present invention.

4 is a flowchart for describing a control process of the steering apparatus according to the present embodiment.

FIG. 5 is a flowchart illustrating a control process of the steering apparatus in the present embodiment when an abnormality occurs in the third motor.

6 is a configuration diagram of a steering apparatus in still another embodiment of the present invention.

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

1 is a configuration diagram of a steering apparatus 200 in one embodiment of the present invention. A steering device 200 as seen from the rear of the vehicle to the front is shown in FIG. 1.

The steering apparatus 200 includes a steering handle 12 operated by a driver, a steering shaft 14 connected to the steering handle 12, and a steering mechanism 50 installed at a lower end of the steering shaft 14. do. The pinion gear 22 is attached to the lower end of the steering shaft 14, which meshes with the rack gear teeth 52b of the first rack shaft 52 in the steering mechanism 50. This forms the rack and pinion mechanism. The first rack shaft 52 is movably supported by the vehicle, and the first rack shaft 52 is movable in the vehicle width direction.

One end of the supporting rod 54 is connected to the end of the first rack shaft 52. The other end of the support rod 54 is connected to a steering arm 56 which supports the right wheel 58 of the vehicle. Steering arm 56 is rotatable about a kingpin (not shown).

When the steering wheel 12 is operated to rotate the steering shaft 14, the rotation of the steering shaft 14 is converted by the steering mechanism 50 into a linear motion of the first rack shaft 52 in the left and right directions of the vehicle. do. This linear motion is converted to rotation of the steering arm 56 with respect to the center pin, and steering of the right wheel 58 is performed.

The steering shaft 14 is divided into an input shaft 14a connected to the steering handle 12 and an output shaft 14b connected to the steering mechanism 50. The output shaft 14b and the input shaft 14a are connected together via the transmission ratio changing device 20.

The transmission ratio changing device 20 can control the transmission characteristics between the steering wheel 12 and the wheels 58 based on information including the vehicle speed, the steering angle, etc., in order to improve steering operability regardless of the road speed. It is a device that can.

The transmission ratio changing device 20 includes a deceleration mechanism 20a, a motor (not shown), and a locking mechanism that directly connects the input shaft 14a and the output shaft 14b. Rotation of the steering handle 12 is transmitted to the housing of the motor of the transmission ratio change device 20 via the input shaft 14a.

The deceleration mechanism 20a of the transmission ratio change device 20 is configured as a differential generating mechanism. The differential generating mechanism drives the motor to rotate the cam of the wave generator fixed to the rotational shaft of the motor, thereby generating a rotational difference between the stator gear and the driven gear via the flexible gear. This rotation difference is derived and added to the rotation of the stator gear transmitted from the input shaft 14a. Thereby, it is possible to generate the steering angle of the output shaft 14b larger than the steering angle of the steering handle 12.

In addition, the locking mechanism 20b is installed in the transmission ratio change device 20. The locking mechanism 20b operates the solenoid to engage the locking pin and the slot, and rotation of the output shaft 14b with respect to the input shaft 14a is prevented. Thereby, the whole delivery ratio change apparatus 20 rotates integrally. A rotation sensor, not shown, is installed in the motor of the transmission ratio change device 20, which is connected to an electronic control unit 100 (hereinafter referred to as "ECU"). The ECU 100 is a control unit of the steering apparatus 200.

The ECU 100 determines whether an abnormality occurs in the transmission ratio change device 20 based on the detection result of the rotation sensor. When an abnormality occurs in the transmission ratio changing device 20, the ECU 100 inputs an operation signal to the locking mechanism 20b to rotate the transmission ratio changing device 20 integrally. This makes it possible to steer the wheels 58 at a fixed transmission ratio via the steering handle 12. As a result, the influence of the abnormality of the transmission ratio changing device 20 on the running state of the vehicle is minimized.

The steering angle sensor 16 is provided in the input shaft 14a, This steering angle sensor 16 detects the rotation angle of the input shaft 14a, and detects the steering angle and steering direction of the steering wheel 12. As shown in FIG. A steering torque sensor 18 is provided on the input shaft 14a, and the steering torque sensor 18 detects steering torque applied to the steering wheel 12 by the driver. The steering angle, steering direction, and steering torque of the steering wheel 12 detected by the steering angle sensor 16 and the steering torque sensor 18 are input to the ECU 100.

The steering mechanism 50 includes a first rack shaft 52 for steering the right wheel of the vehicle, a second rack shaft 53 for steering the left wheel of the vehicle, and a first motor for driving the first rack shaft 52 ( 34a), a second motor 34b for driving the second rack shaft 53, and a differential mechanism 40 provided between the first motor 34a and the second motor 34b.

The first motor 34a is composed of a first stator 30a fixed to the rack housing 51 and a first rotor 31a rotatably supported by the rack housing 51 via the bearing 32. . The first rotor 31a is formed in a cylindrical shape and accommodates one end of the first rack shaft 52. The inner peripheral part of the 1st rotor 31a is provided with the thread part, and a ball screw nut is comprised.

On the other hand, in the outer peripheral part of the one end part of the 1st rack shaft 52, the screw groove type 1st transmission path 52a is formed, and it inserts so that the some electric ball 33 may freely rotate in this transmission path 52a. . Therefore, the ball screw mechanism is comprised by connecting the screw part of the inner peripheral part of the 1st rotor 31a and the 1st transmission path 52a via the transmission ball 33. FIG.

If the first rotor 31a is rotated by the driving of the first motor 34a, the ball screw mechanism described above causes the plurality of balls 33 to rotate the rotational torque of the first rotor 31a in the first transmission path 52a. ) Is converted into thrust in the axial direction of the first rack shaft 52. Thus, the first rack shaft 52 moves in the axial direction. Therefore, the ball screw mechanism functions as a conversion unit for converting the rotational motion of the first motor 34a of relatively low torque into the axial motion of the first rack shaft 52 of relatively high force. Alternatively, other screw mechanisms may be used in place of the ball screw mechanism, such as a screw mechanism without the electric ball 33.

The ECU 100 calculates an auxiliary torque for steering the right wheel 58 of the vehicle on the basis of the detection results by the steering torque sensor 18 and the vehicle speed sensor 24, and calculates the driving torque corresponding to the assistance torque. The driving of the first motor 34a is controlled to generate. In this manner, the first motor 34a is driven, the first rack shaft 52 moves in the axial direction, and steering operation of the steering wheel 12 by the driver is performed to steer the right wheel 58 of the vehicle. Assisted.

The second motor 34b also includes a second stator 30b fixed to the rack housing 51 and a second rotor 31b rotatably supported by the rack housing 51 via the bearing 32. . If the second rotor 31b is rotated by the driving of the second motor 34b, the ball screw mechanism (similar to the above) is applied to the second through the plurality of balls 33 that are driven in the second transmission path 53a. The rotational torque of the motor 34b is converted into thrust in the axial direction of the second rack shaft 53. For this reason, the second rack shaft 53 is moved in the axial direction. Therefore, this ball screw mechanism also functions as a conversion mechanism for converting the rotational motion of the second motor 34b of relatively low torque into the axial motion of the second rack shaft 53 of relatively high force. Alternatively, other screw mechanisms may be used in place of the ball screw mechanism, such as a screw mechanism without the electric ball 33.

Similar to the first rack shaft 52, one end of the supporting rod 54 is connected to the end of the second rack shaft 53, and the other end of the supporting rod 54 supports the steering wheel 58 on the left side of the wheel 58. And 56. Thus, when the second rack shaft 53 is driven in the axial direction, the left wheel 58 of the vehicle is steered.

The ECU 100 calculates an angle of steering the vehicle left wheel 58 based on the result detected by the steering angle sensor 16 and moves the second rack shaft to a length corresponding to the angle. The driving of 34b is controlled. In this way, the second motor 34b is driven, the first rack shaft 52 moves in the axial direction, and steering control in which steering of the left wheel 58 of the vehicle is independently controlled is realized.

A rotation sensor (not shown) is provided inside each of the first motor 34a and the second motor 34b. The detection result of the rotation sensor is input to the ECU 100. Based on the detection result of the rotation sensor, the ECU 100 determines the rotation speed of each of the first motor 34a and the second motor 34b, and determines the rotation speed of each of the first motor 34a and the second motor 34b. It is determined whether or not an abnormality has occurred.

The differential mechanism 40 is provided between the first motor 34a and the second motor 34b. The differential mechanism 40 is composed of two planetary gear mechanisms. One of the two planetary gear mechanisms is composed of a first sun gear 41a, a first planetary gear 42a, and a first internal gear 43a. Another planetary gear mechanism is composed of a second sun gear 41b, a second planetary gear 42b, and a second internal gear 43b. The differential mechanism 40 includes a support plate 46.

The first sun gear 41a, the second sun gear 41b, and the first inner gear 43a are rotatably supported by the rack housing 51, and the first rotor 31a and the second rotor 31b. And coaxial.

The first sun gear 41a is connected to the end of the first rotor 31a via the first transmission shaft 45a. The outer peripheral portion of the first sun gear 41a is provided with a first inner gear 43a, and the outer teeth of the first sun gear 41a and the inner teeth of the first inner gear 43a have a first planetary gear 42a. To interlock. The first inner gear 43a is rotatably supported by the rack housing 51 via the bearing 44.

The second sun gear 41b is connected to the end of the second rotor 31b via the second transmission shaft 45b. A second inner gear 43b is provided on the outer circumferential portion of the second sun gear 41b, and a second planetary gear 42b is provided on the outer teeth of the second sun gear 41b and the inner teeth of the second inner gear 43b. To interlock. The outer circumferential portion of the second inner gear 43b is fixed to the rack housing 51, and the rotation of the second inner gear 43b with respect to the rack housing 51 is suppressed.

The first planetary gear 42a and the second planetary gear 42b are connected to each other by a third transmission shaft 47 via a bearing (not shown) so as to be rotatable with each other. This third transmission shaft 47 is inserted into the through hole of the support plate 46 and is supported so that mutual motion between the three third transmission shafts 47 is regulated.

The specifications of all gears of the first sun gear 41a and the second sun gear 41b, such as the pitch circle radius, the pitch, and the number thereof of the outer gear part, are all the same. Similarly, the specifications of all the gears of the first planetary gear 42a and the second planetary gear 42b, the first inner gear 43a and the second inner gear 43b are all the same.

In the vicinity of the differential mechanism 40 inside the rack housing 51, a locking mechanism 60 for regulating the differential of the differential mechanism 40 is provided. The locking mechanism 60 is fixed to the rack housing 51 and uses a solenoid and a return spring, not shown, to allow the locking pin to move forward (or backward) toward the slot provided in the first inner gear 43a. Let). In this way, the locking pin is engaged in the slot so that the first inner gear 43a is fixed to the rack housing 51 and the rotation of the first inner gear 43a is restricted.

In the above-described configuration, when the locking application of the locking mechanism 60 is released and the first internal gear 43a becomes rotatable, the first internal gear 43a rotates, and the first rotor 31a and the first rotor are rotated. Differential may occur between the two rotors 31b.

In the case where the rotation of the first internal gear 43a is restricted by the locking mechanism 60, the differential applied to the first rotor 31a and the second rotor 31b is regulated by the differential mechanism 40. In this case, each gear of the planetary gear mechanism on the side of the first rotor 31a and the planetary gear mechanism on the side of the second rotor 31b has the same specifications of the gears. When the rotation of the first sun gear 41a and the rotation of the second sun gear 41b are input and output, the ratio of input to output is 1: 1. Therefore, in this case, the first rotor 31a and the second rotor 31b are set in a state where they are connected together via the differential mechanism 40.

The shape of the ball screw nut formed in the inner diameter and the inner circumferential portion of the first rotor 31a is the same as that of the second rotor 31b. The shape of the first transmission path 52a formed on the outer diameter and the outer circumferential portion of the first rack shaft 52 is the same as the outer diameter of the second rack shaft 53 and the transmission path 53a. For this reason, the first rotor 31a and the second rotor 31b are connected together through the differential mechanism 40 and rotate with each other, and the first rack shaft 52 and the second rack shaft 53 are in the same direction. Move the same distance.

The ECU 100 determines whether there is an abnormality in the first motor 34a and / or the second motor 34b according to the detection result of the rotation sensors provided to the first motor 34a and the second motor 34b. When it is determined that an abnormality has occurred in the first motor 34a and / or the second motor 34b, the ECU 100 turns off the solenoid of the locking mechanism 60, and the differential of the differential mechanism 40 by the return spring. Regulate it. Thus, the first rotor 31a and the second rotor 31b are connected via the differential mechanism 40, and the first rack shaft 52 and the second rack shaft 53 move by the same distance in the same direction. do. As a result, when abnormality occurs in the 1st motor 34a and / or the 2nd motor 34b, steering of the said wheel can be performed suitably.

In addition, when the ECU 100 determines that an abnormality has occurred in the first motor 34a or the second motor 34b, the ECU 100 restricts the differential action of the differential mechanism 40 by the locking mechanism 60. The auxiliary operation of the steering operation is performed as described above by activating the other motor which is normally operating. Therefore, even when an abnormality occurs in the first motor 34a or the second motor 34b, the steering operation can be assisted by the driver.

2 is a flowchart illustrating a control process of the steering apparatus 200 in this embodiment. The processing shown in Fig. 2 is repeatedly executed at predetermined time intervals.

The ECU 100 determines whether an abnormality has occurred in the first motor 34a based on the detection result of the rotation sensor provided to the first motor 34a (S11).

If there is no abnormality in the first motor 34a (YES in S11), the ECU 100 has an abnormality in the second motor 34b based on the detection result of the rotation sensor provided to the second motor 34b. It is determined whether or not it has occurred (S12).

When it is determined that there is no abnormality in both the first motor 34a and the second motor 34b (YES in S12), the ECU 100 sends an operation signal independent of each other to the first motor 34a and the second motor. Input to 34b respectively, steering control of a pair of wheels is independently performed (S13). Thereby, the running performance of a vehicle can be improved. At this time, the differential action of the first rack shaft 52 and the second rack shaft 53 is absorbed by the differential mechanism 40.

When it is determined that there is no abnormality in the first motor 34a and there is an abnormality in the second motor 34b (NO in S12), the ECU 100 inputs a predetermined operation signal to the solenoid of the locking mechanism 60. By controlling the differential action of the differential mechanism 40 (S14). Next, the ECU 100 stops the rotation of the second motor 34b determined to be abnormal (S15), and performs steering assist operation of the steering wheel 12 only by the first motor 34a (S16). ).

When an abnormality occurs in the first motor 34a (NO in S11), the ECU 100 inputs a predetermined operation signal to the solenoid of the locking mechanism 60 to regulate the differential action of the differential mechanism 40 ( S17).

Next, the ECU 100 determines whether an abnormality has occurred in the second motor 34b based on the detection result of the rotation sensor provided to the second motor 34b.

If it is determined that there is no abnormality in the second motor 34b (YES in S18), the ECU 100 stops the rotation of the first motor 34a determined to be defective (S19), and the second motor The steering assistance operation of the steering wheel 12 is performed only by 34b (S20).

In addition, when it is determined that there is an error in the second motor 34b (NO in S18), the ECU 100 stops the rotation of the first motor 34a and the second motor 34b that are determined to be abnormal. (S21). Even when an abnormality occurs in both of the first motor 34a and the second motor 34b which respectively perform one of the pair of wheels, it is possible to properly steer the pair of wheels 58.

Next, another embodiment of the present invention will be described. 3 is a diagram showing the configuration of the steering apparatus 200 in this embodiment.

The steering apparatus 200 of this embodiment is substantially the same as the previous embodiment of FIG. For example, similar to the previous embodiment, the steering mechanism 50 of this embodiment includes a first motor 34a, a second motor 34b, and between the first motor 34a and the second motor 34b. And a differential mechanism 40 comprising a planetary gear mechanism provided at.

In this embodiment, the gear 72, the third motor 71 and the reverse input prevention mechanism 70 are provided instead of the locking mechanism 60 in the previous embodiment of FIG. The third motor 71 is fixed to the rack housing 51. The gear 72 meshes with a gear part fixed to the first internal gear 43a. The third motor 71 and the gear 72 are connected via the reverse input prevention mechanism 70.

The reverse input prevention mechanism 70 transmits the input torque to the output shaft when the input torque is given from the input shaft. However, when torque is given from the output shaft, the reverse input prevention mechanism 70 regulates the rotation of the output shaft without transmitting this torque to the input shaft. The lock mechanism is adopted as the reverse input prevention mechanism 70.

In this embodiment, the reverse input prevention mechanism 70 transmits the input torque to the gear 72 when the input torque is given from the third motor 71. However, when the input torque is given from the gear 72, the reverse input prevention mechanism 70 regulates the rotation of the gear 72 without transmitting this torque to the third motor 71.

Therefore, when it is desired to generate a differential action between the first rotor 31a and the second rotor 31b, the third motor 71 must be driven. On the other hand, if the third motor 71 is not driven, the first rotor 31a and the second rotor 31b can be connected via the reverse input prevention mechanism 70. Thus, steering of the pair of wheels can be properly performed and reliability can be improved.

The ECU 100 based on the detection result of the rotation sensor provided to the first motor 34a, the second motor 34b, and the third motor 71, the first motor 34a, the second motor 34b, And whether any of the third motors 71 is abnormal.

When it is determined that no motor is abnormal, the ECU 100 inputs operation signals independent of each other to the first motor 34a and the second motor 34b, respectively, so that steering control of each of the pair of wheels is independently performed. Is performed. If the third motor 71 is not driven in this embodiment, no differential action occurs between the first rotor 31a and the second rotor 31b. Thus, the ECU 100 calculates the differential to be given between the first rotor 31a and the second rotor 31b, and drives the third motor 71 so that the differential is generated. The third motor 71 as well as the first motor 34a and the second motor 34b can also be used to independently perform steering control, respectively, and the load on each motor 34a, 34b, 71 can be reduced. have.

4 is a flowchart for explaining a control process of the steering apparatus 200 in this embodiment. The processing shown in FIG. 4 is repeated at predetermined time intervals.

The ECU 100 determines whether there is an abnormality in the third motor 71 based on the detection result of the rotation sensor provided to the third motor 71 (S31).

When it is determined that an abnormality has occurred in the third motor 71, the process of Fig. 5 described later is executed (NO in S31).

When it is determined that no abnormality has occurred in the third motor 71 (YES in S31), the ECU 100 determines the first motor 34a based on the detection result of the rotation sensor provided to the first motor 34a. In step S32, it is determined whether or not an abnormality has occurred. When there is no abnormality in the first motor 34a (YES in S32), the ECU 100 determines whether there is an abnormality in the second motor 34b based on the detection result of the rotation sensor provided to the second motor 34b. It is determined (S33).

When it is determined that there is no abnormality in the first motor 34a and the second motor 34b (YES in S33), the ECU 100 sends operation signals independent of each other to the first motor 34a and the second. The steering signal of the pair of wheels is independently performed by inputting to the third motor 71 an operation signal respectively input to the motor 34b and allowing the differential action of the differential mechanism 40 (S34). .

When there is no abnormality in the first motor 34a and it is determined that there is an abnormality in the second motor 34b (NO in S33), the ECU 100 causes the first rotor 31a and the second rotor 31b to be used. In order to regulate the differential action therebetween, the rotation of the third motor is stopped (S35), and the rotation of the second motor 34b determined to be abnormal is stopped (S36). Next, the ECU 100 performs steering assist operation of the steering wheel 12 using the first motor 34a which is determined to have no abnormality.

If it is determined that there is an abnormality in the first motor 34a (NO in S32), the ECU 100 causes the third motor to regulate the differential action between the first rotor 31a and the second rotor 31b. The rotation of the motor is stopped (S38). Next, the ECU 100 determines whether there is an abnormality in the second motor 34b based on the detection result of the rotation sensor provided to the second motor 34b (S39).

When it is determined that there is no abnormality in the second motor 34b (YES in S39), the ECU 100 stops the rotation of the first motor 34a which is determined to be abnormal (S40), and determines that there is no abnormality. The steering assist operation of the steering wheel 12 is performed using the second motor 34b thus obtained (S41).

When it is determined that there is an abnormality in the second motor 34b (NO in S39), the ECU 100 stops the rotation of the first motor 34a and the second motor 34b which are determined to be abnormal. (S42).

Before regulating the differential action between the first rotor 31a and the second rotor 31b, the ECU 100 is first detected by a rotation sensor provided to the first motor 34a and the second motor 34b. The difference between the rotation angle of the rotor 31a and the rotation angle of the second rotor 31b is calculated, and the third motor 71 so that the difference between the rotation angle of the first rotor 31a and the rotation angle of the second rotor 31b becomes zero. ) Is activated. Thereby, when abnormality arises in the 1st motor 34a or the 2nd motor 34b, the 1st rotor 31a is a state where the difference of the rotation angle of the 1st rotor 31a and the 2nd rotor 31b was removed. And the differential action between the second rotor 31b can be regulated.

FIG. 5 is a flowchart for explaining a control process of the steering apparatus 200 according to the present embodiment when an abnormality occurs in the third motor. The processing shown in Fig. 5 is repeated at predetermined time intervals.

When it is determined that there is an error in the third motor 71 (NO in S31 of FIG. 4), the ECU 100 stops the rotation of the third motor 71 that is determined to be abnormal. As a result, the differential action between the first rotor 31a and the second rotor 31b is restricted by the lock type reverse input prevention mechanism 70.

Next, the ECU 100 determines whether there is an abnormality in the first motor 34a based on the detection result of the rotation sensor provided to the first motor 34a (S52). Regardless of the case where there is an error in the first motor 34a (YES in S52) or when there is no error (“No” in S52), the ECU 100 determines whether or not the rotation sensor provided to the second motor 34b. Based on the detection result, it is determined whether there is an abnormality in the second motor 34b (S53, S57).

When it is determined that both the first motor 34a and the second motor 34b have no abnormality (YES in S53), the ECU 100 is identical to the first motor 34a and the second motor 34b, respectively. The operation signal is input, and steering assist operation of the steering wheel 12 is executed using the first motor 34a and the second motor 34b (S54).

When it is determined that there is no abnormality in the first motor 34a and there is an abnormality in the second motor 34b (NO in S53), the ECU 100 rotates the second motor 34b which is determined to be abnormal. To stop. Next, the ECU 100 executes steering assist operation of the steering wheel 12 using the first motor 34a determined that there is no abnormality (S56).

When it is determined that there is an abnormality in the first motor 34a and there is no abnormality in the second motor 34b (YES in S57), the ECU 100 rotates the first motor 34a which is determined to be abnormal. To stop (S58). Next, the ECU 100 executes steering assist operation of the steering wheel 12 by using the second motor 34b determined that there is no abnormality (S59).

When it is determined that there is an abnormality in both the first motor 34a and the second motor 34b (No in S57), the ECU 100 determines that the first motor 34a and the second motor ( 34b) is stopped (S60).

Next, another embodiment of the present invention will be described. FIG. 6 is a diagram illustrating a configuration of a steering device 200 in another embodiment.

In this embodiment, the differential mechanism 40 of the above-described embodiment is not provided, and the clutch 80 is provided.

The clutch 80 is composed of an electromagnetic clutch. When current flows in the clutch 80, the clutch 80 connects the first rotor 31a and the second rotor 31b together. The ECU 100 inputs a connection signal to the clutch 80 so that the first rotor 31a and the second rotor 31b are connected to each other. On the other hand, the ECU 100 stops input of the connection signal to the clutch 80, so that the connection of the first rotor 31a and the second rotor 31b is released. Thereby, the 1st rotor 31a and the 2nd rotor 31b can be connected with each other by the simple structure which does not provide the differential mechanism 40. FIG.

In the control process of the steering apparatus of the present embodiment, the control of the clutch 80 which enables or regulates the connection between the two rotors replaces the regulation of the differential action between the two rotors in the flowchart of FIG.

The present invention is not limited to the above-described embodiments, and various conversions and improvements can be made without departing from the scope of the present invention.

For example, the delivery ratio change device 20 can be omitted. In this case, the input shaft 14a and the output shaft 14b of the steering shaft 14 are always connected to each other, and the driver can directly move the first rack shaft 52 by steering the steering handle 12.

In addition, the present application is based on the contents and claims of Japanese Patent Application 2005-035861, filed February 14, 2005 and Japanese Patent Application 2005-238625, filed August 19, 2005, the entire contents of which Is hereby incorporated by reference.

Claims (9)

A steering device for steering a pair of wheels in accordance with steering operation of a steering wheel, A first motor operating in accordance with a steering operation of the steering handle; A first steering shaft for steering one of the pair of wheels; A first conversion unit for converting the rotational motion of the low torque of the first rotor, which is the rotational element of the first motor, into the axial motion of the high force of the first steering shaft; A second motor operating in accordance with a steering operation of the steering handle; A second steering shaft separated from the first steering shaft to steer the other of the pair of wheels; A second conversion unit for converting the rotational motion of the low torque of the second rotor, which is the rotational element of the second motor, into the axial motion of the high force of the second steering shaft; And A connecting unit connecting the first rotor and the second rotor together and disconnecting the first rotor and the second rotor, The connection unit comprises a differential unit providing a differential action between the first rotor and the second rotor and a locking unit regulating the differential unit, The differential unit A first sun gear connected to the first rotor and rotatably supported; A first internal gear rotatably supported and coaxial with the first sun gear; A first planetary gear meshing with the first sun gear and the first internal gear; A second sun gear connected to the second rotor and rotatably supported; A second internal gear that is prevented from rotating and is disposed coaxially with the second sun gear; And A planetary gear mechanism meshing with the second sun gear and the second internal gear, rotatably connected to the first planetary gear, the planetary gear mechanism including a second planetary gear coaxial with the first planetary gear; The locking unit regulates the rotation of the first internal gear to regulate the differential unit. delete delete The steering apparatus of claim 1, wherein the differential unit comprises a third motor for driving the first internal gear. 5. The locking unit as set forth in claim 4, wherein the locking unit has a torque transmission unit provided between the first internal gear and the third motor, the torque transmission unit transferring input torque to the first internal gear when an input torque is given from the third motor. And the input torque from the second internal gear is prevented from being transmitted to the third motor and regulates rotation of the second internal gear. The steering apparatus of claim 1, wherein the steering apparatus further comprises a motor abnormality detecting unit configured to detect an abnormality of any one of a first motor and a second motor, and the connection unit is configured by the motor abnormality detecting unit. 2 When no abnormality is found on both sides of the motor, the first rotor and the second rotor are disconnected, and when the abnormality is detected by at least one of the first motor and the second motor by the motor abnormality detecting unit, the first rotor And a second rotor for connecting the steering apparatus. 7. The method of claim 6, wherein when an abnormality is detected in one of the first motor and the second motor by the motor abnormality detecting unit, the other of the first motor and the second motor is operated according to the steering operation of the steering wheel. Steering device characterized in that. 5. The steering apparatus according to claim 4, wherein the steering apparatus further comprises a rotation angle sensing unit for detecting a difference between the rotation angle of the first motor and the rotation angle of the second motor, wherein the first rotor and the second rotor are joined together by the connection unit. Before the connection, the steering device, characterized in that the difference in the rotation angle detected by the rotation angle detection unit is driven by driving the third motor. The method of claim 1, wherein the steering device Input shaft connected to the steering wheel, An output shaft connected to the first steering shaft or the second steering shaft through a steering gear, and And a transmission ratio changing device having a differential generating mechanism and a motor, operating the differential generating mechanism by driving the motor, and changing a transmission ratio between the input shaft and the output shaft.

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