JP2009143381A - Vehicular steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular steering device capable of suppressing increase of a steering amount when rotating speed of a steering handle is reduced and transmitted to turning wheels. <P>SOLUTION: An ECU 91 for ARS controls reversed-phase turning of rear wheels by a usual rear wheel reversed-phase control mode when an arrangement relation of an upper shaft 211 and a lower shaft 212 is in a usual arrangement, and controls the reversed-phase turning of the rear wheels by a deceleration-time rear wheel reversed-phase control mode when the arrangement relation is in a deceleration arrangement. A turning angle of the rear wheels at the time of controlling the rear wheels by the deceleration-time rear wheel reversed-phase control mode is larger than a turning angle of the rear wheels at the time of controlling the rear wheels by the usual rear wheel reversed-phase control mode. By this, during the deceleration arrangement, the rotation of a vehicle is assisted by large turning of the rear wheels in a reversed-phase even if the steering amount of the steering handle 10 is not increased that much, which suppresses the increase of the steering amount during the deceleration arrangement. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle steering apparatus.

  2. Description of the Related Art Conventionally, as a steering apparatus that steers a vehicle, an electric power steering apparatus is known. An electric power steering (EPS) device is an electric actuator that generates an auxiliary force for assisting a steering force of a steering wheel that is necessary to steer a steered wheel of a vehicle, and an EPS that controls driving of the electric actuator. And a control device. Then, the EPS control device appropriately adjusts the output of the electric actuator according to the vehicle state (vehicle speed, etc.), and the output adjusted in this way is given to the steering force transmission system of the steering device, so that the steering handle Steering assistance is provided.

  In such an electric power steering device, for example, when a sensor for detecting the state of the vehicle or a sensor for detecting a steering force input from the steering wheel by the driver is abnormal, the EPS control device outputs correct information from the sensor. It can no longer be obtained. If the detection information from the sensor is inaccurate, the EPS control device cannot determine the magnitude of the auxiliary force to be output from the electric actuator. Therefore, in such a case, the steering assist of the steering wheel by the electric actuator is stopped in accordance with the fail-safe concept. However, when the steering assist of the steering handle by the electric actuator is suddenly stopped, the driver unexpectedly feels a heavy weight on the operation of the steering handle, so that the steering operation is uncomfortable.

In such a case, the EPS control device does not stop the output of the electric actuator instantaneously when detecting an abnormality of the sensor or the like, but by gradually reducing the output of the electric actuator over a predetermined time. It is possible to adopt a control system that improves the symptoms of suddenly heavy steering handles. In addition, Patent Document 1 reads the detection information from the detection unit that operates normally among the detection units for estimating a plurality of steering states while gradually reducing the output of the electric actuator when abnormality is detected. An electric power steering control device that reduces the bias of the assist torque by the electric motor while monitoring the read detection information is shown. According to this electric power steering control device, the assist torque is gradually reduced when a failure of the sensor or the like is detected, and the assist torque is reduced when it is determined that the steering wheel is turned back by the detection information from the normally operating detection means. By setting it to 0, the problem that the assist torque becomes a steering resistance when the steering wheel is turned back and the steering wheel becomes excessively heavy is improved. For this reason, it is supposed that a better steering feeling can be ensured.
JP 2005-67262 A

  Even in the electric power steering control device disclosed in Patent Document 1, the assist torque (auxiliary force) is not applied after the operation of the electric motor is completely stopped. For this reason, the driver needs a large steering force (for example, steering torque) in order to turn the steering handle, and thus a physical burden is imposed. Therefore, it is desired that the driver can easily rotate the steering means (steering handle) even in a situation where some abnormality occurs and the assist torque (assist force) is not applied.

  In this case, a speed reduction device such as a reduction gear is attached in the middle of the transmission system until the steering force is transmitted to the steered wheels (left and right front wheels), and when the auxiliary force by the electric actuator is applied, the speed reduction device It is also conceivable that the rotation of the steering handle is decelerated by the reduction gear only when the steering handle rotation is not decelerated and the auxiliary force by the electric actuator is not applied. By doing so, when the auxiliary force by the electric actuator is not applied, the steering force is increased by decelerating the rotation of the steering wheel. Therefore, the driver can easily turn the steering handle with a small steering force.

  However, according to the steering apparatus having the above-described reduction gear, since the rotation of the steering wheel is decelerated by connecting the reduction gear to the steering force transmission system, the steered wheels are steered to a predetermined turning angle. The steering amount (for example, the rotation angle) required for the increase increases compared to the case where the speed reducer is not used. That is, since the number of drivers who turn the steering wheel increases, there arises a problem that the operability deteriorates. This problem is a problem that can occur regardless of whether or not steering assistance is provided by the electric power steering apparatus.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle in which an increase in the steering amount is suppressed even when the rotational speed of the steering wheel is reduced and transmitted to the steered wheels. The object is to provide a steering device.

  The vehicle steering device of the present invention includes a front wheel steering device, a rear wheel steering device, and a rear wheel steering control device. The front wheel steering device has a first shaft that is connected to the steering handle and rotates integrally with the steering handle, and a second shaft that is connected to the first shaft and rotates when the rotation of the first shaft is transmitted. The front wheels are steered according to the rotation amount of the second shaft. The rear wheel steering device enables the rear wheels to be steered. The rear wheel steering control device controls the rear wheels by controlling the rear wheel steering device. Further, the front wheel steering device has a reduction device that decelerates the rotation of the first shaft and transmits it to the second shaft.

  In addition, the first axis and the second axis are arranged so that the rotation of the first axis is transmitted to the second axis without going through the speed reducer, and the rotation of the first axis through the speed reducer. It arrange | positions so that the deceleration arrangement | positioning arrange | positioned so that it may be transmitted to a 2nd axis | shaft can be taken. Further, the rear wheel steering control device is configured such that when the first axis and the second axis are in the normal arrangement, the steering angle of the rear wheel is a steering direction opposite to the steering direction of the front wheel, and the front wheel is turned. After normal time when the rear wheel steering device is controlled to control the rear wheel so that the steering angle of the rear wheel at the normal phase, which is the turning angle set according to the steering angle or the steering angle of the steering wheel, is controlled. When the wheel reverse phase control mode and the first axis and the second axis are in a decelerating arrangement, the rear wheel turning angle is a turning direction opposite to the front wheel turning direction, and the front wheel turning angle or The rear wheel at the time of deceleration that is a turning angle that is set according to the steering angle of the steering wheel and that is larger than the normal-phase rear-wheel reverse-phase steering angle when the steering angle of the steering wheel is the same. There is a rear-wheel reverse phase control mode during deceleration in which the rear-wheel steering device is controlled to control the rear wheels so that the reverse-phase steering angle is obtained.

  According to the present invention, as described above, the reverse phase control mode of the rear wheel steering device by the rear wheel steering control device differs depending on whether the first shaft and the second shaft are in the normal arrangement or in the deceleration arrangement. . Specifically, in the normal arrangement, the rear wheels are steered in the normal rear wheel reverse phase control mode so that the rear wheel steered angle becomes the normal rear wheel reverse phase steered angle. On the other hand, in the case of the deceleration arrangement, the rear wheels are steered so that the rear wheel turning angle becomes the rear wheel reverse phase turning angle during deceleration in the deceleration rear wheel reverse phase control mode. The The rear wheel reverse phase turning angle during deceleration is larger than the normal rear wheel reverse phase turning angle when the steering angle is the same. For example, when the steering angle of the steering wheel is θ1, the steering angle of the rear wheel set in the normal rear wheel reverse phase control mode is set to δrn * and the rear wheel reverse phase control mode in deceleration is set. When the turning angle of the rear wheel is δra *, the absolute value | δra * | of δra * is larger than the absolute value | δrn * | of δrn *.

  Here, in the case of the deceleration arrangement, the rotation of the steering handle and the first shaft is decelerated by the reduction gear. Therefore, the front wheel turning amount (steering angle) with respect to the steering amount (for example, steering angle) of the steering wheel in the deceleration arrangement is equal to the front wheel with respect to the steering amount (steering angle) of the same steering handle in the normal arrangement. The steering amount (steering angle) becomes smaller. Specifically, when the steering angle of the steering wheel is θ1, if the turning angle of the front wheels in the normal arrangement is δfn and the turning angle of the front wheels in the deceleration arrangement is δfa, the absolute value of δfa The value | δfa | is smaller than the absolute value | δfn | of δfn. Therefore, when the vehicle turns only depending on the front wheels, if the steering angle of the steering wheel is the same, the turning radius of the vehicle in the deceleration arrangement is larger than the turning radius of the vehicle in the normal arrangement. Become. Therefore, in order to turn the vehicle in the case of the deceleration arrangement as in the case of the normal arrangement, it is necessary to increase the steering amount of the steering wheel (increase the steering angle) than in the case of the normal arrangement. However, in the present invention, the rear wheel control mode in the deceleration arrangement is the rear wheel reverse phase control mode during deceleration, and the reverse phase turning angle of the rear wheel is larger than in the normal arrangement. Is done. For this reason, the turning operation of the vehicle is sufficiently assisted by the large reverse phase steering of the rear wheels. Therefore, an increase in the steering amount (number of hands) of the steering wheel can be suppressed.

  That is, the present invention compensates for the decrease in the front wheel turning amount in the case of the deceleration arrangement by increasing the reverse phase turning amount of the rear wheel, and makes a desired turn without increasing the steering amount of the steering wheel. It is what you do. Thereby, it can be set as the steering apparatus of the vehicle by which the increase in the steering amount was suppressed even at the time of deceleration arrangement | positioning.

  In the above invention, “reverse phase control” is control for turning the rear wheels in a direction (reverse phase) opposite to the turning direction of the front wheels when the vehicle speed is equal to or lower than a predetermined vehicle speed. By performing this control, the turning radius when turning the vehicle is reduced.

  It is preferable that the speed reducer decelerates and outputs the input rotation and outputs the torque while increasing the torque. Examples of such a reduction gear include a planetary gear type reduction mechanism and a worm gear type reduction mechanism. Of these, the planetary gear type reduction mechanism can be used to make the reduction mechanism compact.

  The front wheel steering device includes an auxiliary force applying unit that is connected to the second shaft and generates an auxiliary force for assisting steering of the steering wheel. The rear wheel steering control device has a normal arrangement. And when the assisting force applying means is in a normal state assisting the steering of the steering wheel by the assisting force, the rear wheel steering device is controlled in the normal rear wheel reverse phase control mode, and the vehicle is decelerated and assisted. When the force applying means is in an assist stop state in which steering of the steering wheel is not assisted by an assist force, the rear wheel steering device may be controlled by the rear wheel reverse phase control mode during deceleration. According to this, since the rear-wheel steering control is performed in the rear-wheel reverse phase control mode during deceleration when the assist is stopped, the steering load that increases due to the stop of the steering assist (assist) by the assist force applying means is increased. The rotation torque of the first shaft is increased by the operation of the reduction gear and is transmitted to the second shaft to compensate. In addition, the reduction of the front wheel turning amount due to the rotation of the first shaft being decelerated and transmitted to the second shaft by the operation of the speed reducer is a large reverse of the rear wheels in the rear wheel reverse phase turning control mode during deceleration. Compensated by phase turning. Therefore, even when the assist is stopped, an increase in the steering torque input by the driver to the steering wheel can be suppressed, and an increase in the steering amount (number of operations) when the steering wheel is turned can also be suppressed. For this reason, it is possible to provide a steering apparatus with good operability.

  In this case, when the rear wheel steering control device controls the rear wheel steering device in the deceleration rear wheel reverse phase control mode and the steering angle of the steering wheel is the same, the normal rear wheel reverse phase control is performed. The rear radius of the vehicle when the rear wheel steering device is controlled in the control mode and the rear radius of the vehicle when the rear wheel steering device is controlled in the reverse wheel reverse phase control mode during deceleration are equal to each other. It is good to control the wheel steering device. According to this, since the turning radius of the vehicle is the same in the normal state and in the assist stop state, the driver steers the vehicle as in the normal state even in the assist stop state. be able to.

  Hereinafter, a vehicle steering apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows the configuration of a vehicle steering apparatus according to this embodiment.

  The vehicle steering device includes a front wheel steering device 1 and a rear wheel steering device 8. The front wheel steering apparatus 1 includes a steering handle 10, a steering column 20, an EPS unit 23, an intermediate shaft 30, a pinion shaft 40, and a rack bar 50, and controls the steering force input by the driver to the steering handle 10. This is a device for turning the left and right front wheels FW1, FW2 by transmitting to the front wheels FW1, FW2. The steering handle 10 is assembled to a steering column 20, and the steering column 20 is connected to a rack bar 50 via an EPS unit 23, an intermediate shaft 30 and a pinion shaft 40. The rack bar 50 is connected to the left and right front wheels FW1, FW2 via tie rods (not shown).

  FIG. 3 is a side cross-sectional view of the steering column 20 cut along the axial direction (column axial direction). As shown in FIG. 3, the steering column 20 includes a steering main shaft 21 and a column tube 22 that accommodates the steering main shaft 21 and supports the steering main shaft 21 so as to be rotatable.

  As shown in FIG. 3, the steering main shaft 21 includes an upper shaft 211 that is the first axis of the present invention and a lower shaft 212 that is the second axis of the present invention. The upper shaft 211 is formed in a hollow shape, and is coupled to the steering handle 10 so as to be integrally rotatable on the right end side (vehicle rear end side) in the drawing. Male spline teeth 211a are formed on the outer periphery of the upper shaft 211 on the left end side (the vehicle front end side) in the figure over a predetermined length along the axial direction. The lower shaft 212 is also formed in a hollow shape. Female spline teeth 212a are formed on the inner circumference of the lower shaft 212 over a predetermined length along the axial direction. A portion on the left side of the upper shaft 211 is inserted from the right side of the lower shaft 212 to the inner peripheral side of the lower shaft 212. At this time, the female spline teeth 212 a formed on the lower shaft 212 can mesh with the male spline teeth 211 a formed on the upper shaft 211. Therefore, when the spline teeth 211a and 212a are engaged with each other, both the shafts 211 and 212 can be moved relative to each other in the axial direction, and the lower shaft 212 is rotatably connected by the rotation of the upper shaft 211 being transmitted. It becomes a state.

  The column tube 22 has a function as a support member for rotatably supporting the steering main shaft 21 and includes two tubular members, an upper tube 221 and a lower tube 222. As shown in FIG. 3, the upper tube 221 and the lower tube 222 are both formed in a hollow cylindrical shape. In addition, the right side portion of the lower tube 222 is inserted into the upper tube 221 from the left side of the upper tube 221, and both the tubes 221 and 222 are arranged coaxially so as to have an overlapping region in the axial direction. . FIG. 4 is an enlarged cross-sectional view showing the vicinity of the overlapping region of both tubes 221 and 222.

  As shown in FIG. 3, the upper tube 221 can rotate the upper shaft 211 through a bearing Br provided integrally on the inner periphery of the right end portion (vehicle rear end portion) and integrally in the axial direction. It is supported so that it can move (that is, it cannot move in the axial direction). As shown in FIGS. 3 and 4, the upper tube 221 has a through hole 221a penetrating from the inner peripheral side to the outer peripheral side in the upper part of the left end side in the figure, and the left side in the figure. A long hole 221b is formed in the lower part on the side along the axial direction. A solenoid pin 272 of a solenoid 27 described later can be inserted into the through hole 221a, and an eccentric cam 253 of a lock mechanism 25 described later is inserted into the long hole 221b.

  As described above, the lower tube 222 is inserted into the left side of the upper tube 221, and the upper tube 221 is slidable in the axial direction via a guide member or the like. 221 is supported. A groove 222a is formed in the upper portion of the lower tube 222 inserted into the upper tube 221 over a predetermined distance in the axial direction as shown in FIGS. The groove 222a defines a movement range of a solenoid pin 272, which will be described later, in the column axial direction (the axial direction of the steering main shaft 21 and the column tube 22).

  As shown in FIG. 3, the EPS unit 23 is disposed at the left end portion (vehicle front end portion) of the lower tube 222. The EPS unit 23 has a housing 231. The lower tube 222 is fixed to the housing 231. As a result, the steering column 20 is connected to the EPS unit 23. The EPS unit 23 is a device that generates an assist torque Ta as an assisting force for assisting steering of the steering handle 10, and the steering handle 10 is steered when the left and right front wheels FW1, FW2 are steered by the generated assist torque Ta. To assist.

  FIG. 2 is a schematic side view showing a state in which the steering column 20 is attached to the vehicle body. As shown in FIG. 2, the column tube 22 of the steering column 20 is attached to the steering support member SS provided in the instrument panel reinforcement IR in an inclined posture so that the front side of the vehicle is positioned downward. Thereby, the whole steering column 20 is supported by the steering support member SS which is a member on the vehicle body side.

  Further, the housing 231 of the EPS unit 23 is rotatably supported by an arm AR provided at a lower front portion of the steering support member SS via a support pin 231a. Therefore, the EPS unit 23 and the steering column 20 connected to the EPS unit 23 can be turned up and down around the support pin 231a (it can be tilted around the axis (tilt center) of the support pin 231a). This is supported by the member (steering support member SS).

  The EPS unit 23 includes the housing 231 connected to the lower tube 222 and the EPS electric motor 232 assembled to the housing 231. As shown in FIG. 3, the housing 231 includes an input shaft 233 connected to the lower shaft 212, an output shaft 234 connected to the intermediate shaft 30, and a torsion bar 235 connected to the input shaft 233 and the output shaft 234. A speed reducer 236 that decelerates the rotational speed of the electric motor 232 for EPS and transmits it to the output shaft 234, and a steering torque that the driver inputs from the steering handle 10 based on the amount of twist detected by the torsion bar 235. A steering torque sensor 62 for calculating T is accommodated. The lower shaft 212 is connected to the input shaft 233 accommodated in the housing 231 so that the lower shaft 212 cannot be displaced in the axial direction with respect to the lower tube 222.

  As shown in FIG. 2, the intermediate shaft 30 is connected to the EPS unit 23 (the output shaft 234) via the upper universal joint UJ at the upper end portion. Moreover, it connects with the pinion shaft 40 via the lower universal joint LJ in the lower end part. The intermediate shaft 30 can be contracted in the axial direction in order to prevent the steering column 20 and the steering handle 10 from being pushed out to the driver side in the event of a vehicle collision.

  The pinion shaft 40 is connected to the rack bar 50 as shown in FIG. Specifically, a pinion gear 41 is integrally provided at the end of the pinion shaft 40, and the pinion gear 41 meshes with a rack gear 51 formed on the rack bar 50, whereby the pinion shaft 40 and the rack bar 50 are engaged. It is connected. Therefore, the rotational force of the pinion shaft 40 is converted into the axial movement force of the rack bar 50 by the meshing of the rack and pinion method. Therefore, the rack bar 50 is displaced in the axial direction when the rotational force from the pinion shaft 40 is transmitted.

  In the front wheel steering apparatus 1 in the present embodiment, the upper shaft 211 and the lower shaft 212 constitute the steering main shaft 21 as described above, and the lower shaft 212 is the EPS unit 23, the intermediate shaft 30, the pinion shaft 40, and the rack bar 50. Are mechanically connected to each other. For this reason, according to the front wheel steering device 1 of the present embodiment, when the lower shaft 212 rotates, the rack bar 50 is axially displaced by an amount corresponding to the amount of rotation, whereby the left and right front wheels FW1, FW2 are steered. The

  As shown in FIGS. 2 and 3, the movable bracket 24 is integrally fixed to the outer periphery of the lower portion of the upper tube 221 on the left side (the vehicle front side). The movable bracket 24 is assembled via a lock mechanism 25 to a fixed bracket 26 provided at the vehicle rear lower portion of the steering support member SS. The lock mechanism 25 is a well-known one, and as shown in FIGS. 2 to 4, a tilt long hole (an arc-shaped long hole centered on the tilt center) 26a (see FIG. 2) provided in the fixed bracket 26 and a movable bracket 24, a locking shaft 251 extending in the left-right direction of the vehicle through a telescopic elongated hole 24a (see FIGS. 3 and 4) extending in the column axis direction provided in 24, and screwed to one end of the locking shaft 251 A nut (not shown), an operation lever 252 assembled to the other end of the lock shaft 251 so as to be integrally rotatable, and a portion on the lock shaft 251 between the fixed bracket 26 and the operation lever 252. A lock cam unit (not shown) and an eccentric cam 253 assembled so as to be integrally rotatable on the outer periphery in the axial direction intermediate portion of the lock shaft 251 are provided.

  The operation lever 252 can rotate integrally with the locking shaft 251 around the axis of the locking shaft 251. Further, the lock cam unit (not shown) increases the frictional engagement force between the fixed bracket 26 and the movable bracket 24 by rotating the operation lever 252 in the counterclockwise direction in FIG. 2, and the operation lever 252 in FIG. The frictional engagement force between the fixed bracket 26 and the movable bracket 24 is reduced by rotation in the clockwise direction. The eccentric cam 253 is inserted through a long hole 221b formed in the upper tube 221 as shown in FIGS. 3 and 4, and is used for locking in accordance with the rotation of the operation lever 252 in the counterclockwise direction in FIG. The shaft 251 is rotated counterclockwise in FIGS. 3 and 4 to engage the lower outer periphery of the lower tube 222 and lift the lower tube 222 upward. As a result, the lower tube 222 abuts the upper tube 221 at an upper portion thereof, and the lower tube 222 is pressed against the upper tube 221. On the other hand, the eccentric cam 253 is detached from the outer periphery of the lower portion of the lower tube 222 by the rotation of the locking shaft 251 in the clockwise direction in FIGS. 3 and 4 accompanying the rotation of the operation lever 252 in the clockwise direction in FIG. As a result, the pressing force generated between the upper tube 221 and the lower tube 222 is weakened.

  Therefore, when the driver turns the operation lever 252 counterclockwise in FIG. 2 to a predetermined lock position, the friction engagement force and the pressing force are strengthened, and the steering column 20 is fixed to the fixed bracket 26. The By this fixing, the steering column 20 is locked. In the locked state, the tilting operation of the steering column 20 (the operation performed to adjust the vertical position of the steering handle 10 and the tilting operation of the steering column 20 around the axis (tilt center) of the support pin 231a). ) And telescopic operations (operations performed to adjust the position of the steering handle 10 in the front-rear direction, and the movement of the upper shaft 211 and the upper tube 221 in the column axial direction with respect to the lower shaft 212 and the lower tube 222) are restricted. Is done.

  Further, when the driver turns the operation lever 252 clockwise in FIG. 2 to a predetermined unlock position, the friction engagement force and the pressing force are weakened, and the steering column 20 is fixed to the fixing bracket 26. The steering column 20 is unlocked and released. In this unlocked state, the steering column 20 can perform a tilting operation and a telescopic operation. When the lock mechanism 25 is in the unlocked state, a spring (not shown) interposed between the fixed bracket 26 and the eccentric cam 253 elastically restricts the downward movement of the steering column 20.

  As shown in FIGS. 3 and 4, a solenoid 27 is disposed above the left end side of the upper tube 221. FIG. 5 is a cross-sectional view taken along the line AA in FIG. 3 and shows a state where the solenoid pin 272 is attached to the upper tube 221. As shown in these drawings, the solenoid 27 has a solenoid body 271 assembled to the upper surface of the left end of the upper tube 221 in FIGS. 3 and 4 via a bracket, and can move forward and backward in the solenoid body 271. An assembled solenoid pin 272 is provided. The solenoid body 271 has a spring (not shown), and the spring urges the solenoid pin 272 in a direction protruding from the solenoid body 271 (downward direction in FIG. 3). The solenoid main body 271 includes a coil (not shown). When this coil is energized, it generates an attractive force that acts in the direction in which the solenoid pin 272 retracts into the solenoid body 271 (upward in FIG. 3).

  When the coil of the solenoid body 271 is not energized, the solenoid pin 272 is inserted through the through-hole 221a formed in the upper tube 221 by the urging force of the spring, and a part (lower end in FIG. 3) is the lower tube. The state is entered into the groove 222 a formed in 222. Therefore, when the telescopic operation of the steering column 20 is performed in this state, the telescopic adjustment stroke (the length in which the upper shaft 211 and the upper tube 221 can move in the axial direction in the telescopic operation) is the solenoid pin 272 in the groove 222a. It is regulated within a range that can move in the column axis direction, that is, within a range L (see FIG. 3). Within this range L, the axial positions of the shafts 211 and 212 are designed so that the male spline teeth 211a of the upper shaft 211 always mesh with the female spline teeth 212a of the lower shaft 212.

  Further, when the coil of the solenoid body 271 is energized and the solenoid pin 272 is retracted from the groove 222a, the telescopic adjustment stroke is not limited to the range L. In this case, the telescopic adjustment stroke is regulated by engaging the locking shaft 251 with both ends of the telescopic long hole 24a in the axial direction. That is, when the telescopic operation is performed in the direction in which the steering handle 10 is pushed from the passenger compartment side (the left direction in FIG. 3) when the solenoid pin 272 is retracted from the groove 222a, the upper shaft 211 and the movable bracket 3 moves to the left in FIG. 3 with respect to the lower shaft 212 and the lower tube 222, but this movement is restricted by the locking shaft 251 engaging the right end of the telescopic elongated hole 24a. On the other hand, when the telescopic operation is performed in the direction in which the steering handle 10 is pulled out to the passenger compartment side (the right direction in FIG. 3), the upper shaft 211 and the movable bracket 24 are shown in FIG. Although it moves to the right, this movement is restricted by the locking shaft 251 engaging with the illustrated left end of the telescopic elongated hole 24a. That is, the telescopic adjustment stroke in this case is restricted within a range in which the locking shaft 251 can move in the column axial direction through the telescopic long hole 24a, that is, within a range L1 (see FIG. 3). Here, the telescopic operation range when the telescopic adjustment stroke range is L1 includes the telescopic operation range when the stroke range is L and is larger than the telescopic operation range when the stroke range is L. It is said. In particular, the telescopic operation range when the range is L1 is set to be larger than the telescopic operation range when the range is L when the telescopic operation is performed in the direction in which the steering handle 10 is pulled toward the passenger compartment. It is good to be done. However, when the telescopic operation is performed in the direction in which the steering handle 10 is pushed in from the passenger compartment side, the range may be set to be larger than the telescopic operation range when the range is L.

  Next, an electric control device that controls the operation of the solenoid 27 and the operation of the EPS unit 23 will be described. As shown in FIG. 1, the electric control device includes a vehicle speed sensor 61, a steering torque sensor 62, a steering angle sensor 63, a front wheel turning angle sensor 64, an acceleration sensor 65, and a motor rotation angle sensor 66. The vehicle speed sensor 61 detects and outputs the vehicle speed V of the vehicle. The steering torque sensor 62 is assembled in the housing 231 of the EPS unit 23 as described above, and detects and outputs the steering torque T input via the steering handle 10.

  The steering angle sensor 63 is assembled to the steering main shaft 21 (more specifically, the upper shaft 211), detects the rotation angle of the steering handle 10, and outputs it as the steering angle θ. Here, the steering angle sensor 63 detects the steering angle θ as a positive angle when the steering handle 10 is steered clockwise (clockwise) from the neutral position, and steers in the counterclockwise (counterclockwise) direction. When this is done, the steering angle θ is detected as a negative angle. The front wheel turning angle sensor 64 is assembled to the rack bar 50, detects the amount of displacement of the rack bar 50 in the axial direction, and is the turning angle of the left and right front wheels FW1, FW2 corresponding to the detected amount of displacement. The front wheel turning angle δf is output. Here, the front wheel turning angle sensor 64 is when the rack bar 50 is displaced rightward from the neutral position, which is the position when the vehicle is traveling straight (that is, when the front wheels are turned clockwise from the neutral state). The front wheel turning angle δf is detected as a positive angle, and the front wheel turning angle δf is detected as a negative angle when the vehicle is displaced leftward from the neutral position (that is, when the front wheel is turned counterclockwise from the neutral state). To do. The acceleration sensor 65 is assembled at the center of gravity of the vehicle, for example, and detects and outputs a lateral acceleration G generated in the vehicle. The motor rotation angle sensor 66 is assembled, for example, in the motor housing of the EPS electric motor 232, detects the rotation angle of the motor rotation shaft, and outputs it as the motor rotation angle θm.

  The electric control device includes an EPS electronic control unit (hereinafter referred to as an EPS ECU) 70, and the various sensors described above are connected to the EPS ECU 70. The EPS ECU 70 has a microcomputer including a CPU, a ROM, a RAM, and the like as main components, and controls the operations of the solenoid main body 271 and the EPS electric motor 232 using the detected values of the sensors. . Therefore, a solenoid drive circuit 67 for driving and controlling the solenoid body 271 and an EPS drive circuit 68 for driving and controlling the EPS electric motor 232 are connected to the output side of the EPS ECU 70.

  In addition, the electric control device includes an alarm device 71. The alarm device 71 has a function of notifying the driver that the operation of the EPS unit 23 is stopped and the steering assist by the assist torque Ta is not performed (assist stop state). The alarm device 71 is electrically connected to the EPS ECU 70, and includes a display unit 711 assembled at a position (for example, in a meter cluster) that can be visually recognized by the driver, and an audio output unit 712 that outputs audio. ing. The display unit 711 includes, for example, a lamp or a display panel. The audio output unit 712 includes, for example, a speaker.

  Further, the front wheel steering device 1 of the present embodiment includes a speed reducing device 28 that decelerates the rotation of the upper shaft 211 and transmits it to the lower shaft 212 as shown in FIGS. 3 and 4. The speed reduction device 28 employs a planetary gear type speed reduction mechanism, and includes a planetary gear 281, male spline teeth 211 a (hereinafter also referred to as sun gear 211 a) provided on the upper shaft 211, and a lower shaft 212. And the ring gear 222b provided on the lower tube 222. The sun gear 211a is an input element, the carrier 212b is an output element, and the ring gear 222b is a reaction force element. FIG. 6 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIGS. 3 and 4, the carrier 212 b is formed on the lower shaft 212. In the lower shaft 212, the outer diameter from the right side of the portion where the female spline teeth 212a are formed to the tip end portion is enlarged, and this enlarged cylindrical portion is the carrier 212b. As shown in FIG. 6, the carrier 212b is formed with a plurality of (for example, three) hole portions 212c penetrating in the radial direction from the inner periphery to the outer periphery. The plurality of holes 212c are formed at the same axial position at a substantially intermediate position in the axial direction of the carrier 212b. Planetary gears 281 are respectively disposed in the plurality of holes 212c. The planetary gear 281 is a cylindrical spur gear having external teeth on its peripheral surface. The planetary gear 281 is disposed in the hole 212c with its axial direction parallel to the column axial direction so that it can mesh with the sun gear 211a depending on the axial position of the upper shaft 211. In the present embodiment, a plurality of (for example, three) planetary gears 281 are provided. A pin 282 is rotatably attached to the planetary gear 281 along its axis. The pin 282 extends in the column axis direction in the hole 212c, and both ends thereof are rotatably supported by the carrier 212b. The planetary gear 281 is supported by the carrier 212b via the pin 282. The carrier 212b may not be formed integrally with the lower shaft 212, but may be formed as a separate body and connected to the lower shaft 212 so as to be coaxially rotatable.

  The ring gear 222b is formed in a spur gear shape so as to be able to mesh with the planetary gear 281 on the inner periphery on the distal end side (the right end side in FIGS. 3 and 4) of the lower tube 222. The lower tube 222 and the lower shaft 212 are axially positioned so that a portion where the ring gear 222b is formed and a hole 212c formed in the carrier 212b face each other. The planetary gear 281 disposed in the hole 212c is disposed so as to always mesh with the ring gear 222b.

  When the positional relationship between the upper shaft 211 and the lower shaft 212 in the axial direction is the state shown in FIGS. 3 and 4, the planetary gear 281 has a column axial position that does not coincide with the formation site of the sun gear 211a. The sun gear 211a is not meshed. Therefore, the sun gear 211a (male spline teeth 211a) does not mechanically connect to the reduction gear 28 having the planetary gear 281 but directly meshes with the female spline teeth 212a formed on the lower shaft 212. For this reason, the rotation of the upper shaft 211 is directly transmitted to the lower shaft 212 through the meshing of the sun gear 211a and the female spline teeth 212a without passing through the reduction gear 28. The arrangement of the upper shaft 211 and the lower shaft 212 in such a state (a state where the sun gear 211a and the female spline teeth 212a are engaged with each other) is a normal arrangement.

  When the upper shaft 211 moves rightward from the position shown in FIGS. 3 and 4, the sun gear 211 a and the female spline teeth 212 a are disengaged, and the sun gear 211 a meshes with the planetary gear 281. Such a state is shown in FIG. 7 and FIG. At this time, the solenoid pin 272 is retracted into the solenoid body 271 and the telescopic adjustment stroke range is set to L1 (see FIG. 3). In this case, the rotation of the upper shaft 211 is transmitted to the lower shaft 212 via the speed reducer 28 when the sun gear 211a and the planetary gear 281 are engaged with each other. The arrangement of the upper shaft 211 and the lower shaft 212 in the state shown in FIGS. 7 and 8 (the state in which the sun gear 211a and the planetary gear 281 are engaged) is a reduction arrangement. Therefore, in the steering device of the present embodiment, the upper shaft 211 and the lower shaft 212 are arranged so that the normal arrangement and the deceleration arrangement can be taken by the axial relative movement of the shafts 211 and 212. .

  As shown in FIG. 1, the rear wheel steering device 8 includes an ARS (Active Rear Steer) electric motor 81, a rear wheel steering shaft 82, and a ball screw mechanism 83. It is a device that steers the wheels RW1 and RW2. The rear wheel steering shaft 82 is a shaft-like member whose both ends are connected to the left and right rear wheels RW1 and RW2 via tie rods and knuckle arms (not shown), and the left and right rear wheels RW1 are displaced by displacement in the axial direction. , RW2 is steered. The ARS electric motor 81 is assembled on the outer periphery of the rear wheel steering shaft 82. A ball screw mechanism 83 is also assembled around the outer periphery of the rear wheel steering shaft.

  Further, the steering device in the present embodiment includes a rear wheel steering control device 9 that controls the rear wheel steering device 8. The rear wheel steering control device 9 includes an ARS electric control unit (hereinafter referred to as an ARS ECU) 91 that controls the ARS electric motor 81, and an ARS drive circuit 92 that drives the ARS electric motor 81. . The ARS ECU 91 is connected to a rear wheel turning angle sensor 93, a vehicle speed sensor 61, a steering angle sensor 63, a front wheel turning angle sensor 64, a yaw rate sensor (not shown), and the like. The rear wheel turning angle sensor 93 is constituted by a rotation angle sensor incorporated in the ARS electric motor 81, and detects the turning angle δr of the left and right rear wheels RW1 and RW2 by detecting the rotation angle of the ARS electric motor 81. To do. Here, the rear wheel turning angle sensor 93 uses the turning angle when the rear wheel turns clockwise from the turning position (neutral position) of the rear wheel when the vehicle is traveling straight ahead as a positive turning angle. The wheel turning angle δr is detected, and the rear wheel turning angle δr is detected with the turning angle when turning counterclockwise as a negative turning angle. The vehicle speed sensor 61 detects the vehicle speed V as described above. The yaw rate sensor detects the yaw rate around the center of gravity of the vehicle body.

  The ARS ECU 91 includes a microcomputer including a CPU, a ROM, a RAM, and the like as main components. By repeatedly executing a predetermined rear wheel turning program every predetermined short time, a detection signal of each sensor is obtained. Accordingly, the ARS electric motor 81 is driven and controlled via the ARS drive circuit 92. When the ARS electric motor 81 is operated, the rotation is decelerated by the ball screw mechanism 83 and the rotational motion is converted into a linear motion. Then, the converted linear motion is transmitted to the rear wheel steering shaft 82, and the left and right rear wheels RW1 and RW2 connected to the rear wheel steering shaft 82 are steered. In this way, the rear wheel steering control device 9 controls the rear wheel steering device 8.

  In the steering apparatus having the above-described configuration, the EPS ECU 70 rotates the steering handle 10 by the driver when the EPS unit 23 is in a normal state in which the assist torque Ta can be generated by the operation of the EPS electric motor 232. A predetermined program (not shown) is executed to apply an appropriate assist torque Ta to the dynamic operation (steering operation). Thereby, the output of the EPS electric motor 232 is transmitted to the output shaft 234 as the assist torque Ta, and the assist torque Ta assists the turning operation of the steering handle 10.

  More specifically, the EPS ECU 70 inputs the vehicle speed V detected by the vehicle speed sensor 61 and the steering torque T detected by the steering torque sensor 62. Based on the input vehicle speed V and steering torque T, a preset assist torque Ta is determined. Here, the magnitude of the assist torque Ta increases, for example, as the detected vehicle speed V decreases (decreases in speed) and decreases as the detected vehicle speed V increases (increases in speed). Is set.

  When the EPS ECU 70 determines the assist torque Ta, the EPS ECU 70 determines a drive current for driving the EPS electric motor 232 in accordance with the determined assist torque Ta, and drives and controls the EPS drive circuit 68. The drive current thus supplied is supplied to the EPS electric motor 232. Thus, the EPS electric motor 232 is rotationally driven by the supplied drive current. The rotational torque of the EPS electric motor 232 is transmitted to the output shaft 234 via the speed reducer 236. The rotational torque thus transmitted assists the turning operation of the steering handle 10 as the assist torque Ta. As a result, the steering torque T input by the driver can be reduced.

  Further, in the normal state where the assist torque Ta assists the turning operation of the steering handle 10, the EPS ECU 70 does not supply power to the solenoid 27. For this reason, the solenoid pin 272 protrudes from the solenoid body 271 toward the column tube 22 by the biasing force of the spring. As a result, the tip of the solenoid pin 272 enters the groove 222a formed in the lower tube 222 through the through hole 221a formed in the upper tube 221, and the telescopic adjustment stroke range is restricted to the range L.

  On the other hand, the ARS ECU 91 executes reverse phase control of the left and right rear wheels RW1, RW2 by executing the ARS reverse phase control program shown in FIG. Here, the reverse phase control is a control in which the left and right rear wheels RW1 and RW2 are steered in a direction (reverse phase) opposite to the steering direction of the left and right front wheels FW1 and FW2 when the vehicle speed is equal to or lower than a predetermined vehicle speed. Yes, thereby reducing the turning radius when the vehicle turns. The ARS ECU 91 can also control the steering of the left and right rear wheels RW1 and RW2 by executing various control programs in addition to such reverse phase control.

  The ARS reverse phase control program is started in step S50 of FIG. 12 (hereinafter, simply referred to as S50. Other steps are also the same), and it is determined in next S52 whether or not the vehicle speed V is less than V0. To do. This determination can be made based on whether or not the vehicle speed detected by the vehicle speed sensor 61 is less than V0. If the determination result in S52 is No, the process proceeds to S64 and the execution of this program is terminated. That is, when the vehicle speed is equal to or higher than the predetermined vehicle speed, the reverse phase control of the rear wheels RW1 and RW2 is not performed. If the determination result in S52 is Yes, the process proceeds to S54.

  In S54, the ARS ECU 91 calculates the target turning angle δrn * of the left and right rear wheels RW1, RW2. This target turning angle δrn * is a direction opposite to the turning direction of the turning angle δf of the left and right front wheels FW1 and FW2 (that is, the state where the left and right front wheels FW1 and FW2 are turned rightward with respect to the straight direction of the vehicle). In this case, the angle is set to the left direction, and the right and left front wheels FW1 and FW2 are turned to the left in the state where the left and right front wheels FW1 and FW2 are steered in the left direction with respect to the vehicle straight traveling direction. The target turning angle δrn * depends on the turning angle δf of the left and right front wheels FW1 and FW2 detected by the front wheel turning angle sensor 64 or the steering angle θ of the steering handle 10, or in addition to these, other vehicle conditions Can be set appropriately and optimally in consideration of an amount (for example, yaw rate). This target turning angle δrn * is a normal rear wheel reverse phase turning angle in the present invention.

  After the target turning angle δrn * is determined in S54, the ARS ECU 91 proceeds to S56 and determines whether or not the abnormality flag IFLG is “0”. This abnormality flag IFLG is a flag indicating whether or not the EPS unit 23 or the electric control device is abnormal, and is based on an assist torque Ta generated by the EPS unit 23 when the EPS unit 23 or the electric control device is normal. When the steering assist is performed, that is, in the normal state, it is set to “0”, and when it is abnormal and the steering assist by the assist torque Ta is not performed, it is set to “1”. If the EPS unit 23 is in the normal state, the determination result is Yes. In this case, the process proceeds to S58. In S58, the ARS ECU 91 drives and controls the ARS electric motor 81 so that the left and right rear wheels RW1 and RW2 become the target turning angle δrn * based on the detected turning angle δr of the left and right rear wheels RW1 and RW2. As a result, the left and right rear wheels RW1, RW2 are set to the target turning angle δrn *. Thereafter, the process proceeds to S64, and the execution of this program is terminated. By such reverse phase control, the left and right rear wheels RW1, RW2 are steered in the direction opposite to the steered direction of the left and right front wheels FW1, FW2, and the turning radius of the vehicle is reduced.

  Here, in the normal state, the EPS ECU 70 does not energize the coil of the solenoid 27 as described above, so the telescopic adjustment stroke range is set to the range L. When the telescopic adjustment stroke range is the range L, the upper shaft 211 and the lower shaft 212 are normally arranged, and the male spline teeth 211 a formed on the lower shaft 212 are formed by the male spline teeth 211 a formed on the upper shaft 211. Biting into. As described above, in the steering device of the present embodiment, when the positional relationship between the upper shaft 211 and the lower shaft 212 is the normal configuration and the EPS unit 23 is in the normal state, the ARS ECU 91 performs the ARS reverse phase in FIG. In the control program, the steps S52, S54, S56, S58 are executed to set the target turning angle of the left and right rear wheels RW1, RW2 to δrn *. Thus, the reverse phase control mode in which the target turning angle is δrn * is the normal rear wheel reverse phase control mode. In the normal rear wheel reverse phase control mode, the steering of the steering wheel 10 is assisted by the EPS unit 23, and the rotation of the steering wheel 10 and the upper shaft 211 does not pass through the reduction gear 28 (that is, the reduction ratio is 1). As it is) is transmitted to the lower shaft 212 and further transmitted to the left and right front wheels FW1, FW2 via the EPS unit 23, the intermediate shaft 30, the pinion shaft 40, and the rack bar 50.

  By the way, when an abnormality occurs in the EPS unit 23 and the electric control device that controls the EPS unit 23, for example, when an abnormality occurs in each sensor or the EPS electric motor 232, the EPS ECU 70 operates in accordance with the fail-safe concept. The driving of the electric motor 232 is stopped to stop the steering assist by the assist torque Ta, and the operation state of the EPS unit 23 is shifted from the normal state to the assist stop state. When shifting from the normal state to the assist stop state, the driver cannot receive the steering assist by the assist torque Ta, and therefore the steering handle 10 must be rotated by the large steering torque T. Therefore, the EPS ECU 70 determines whether or not the EPS unit 23 and the electric control device (various sensors) are abnormal, and if abnormal, sets the operating state of the EPS unit 23 to the assist stop state and assists. The rotation of the steering handle 10 is decelerated by the reduction gear 28 and transmitted to the left and right front wheels FW1, FW2 so that the driver can easily turn the steering handle 10 by reducing the steering torque T even in the stopped state. The abnormality process is repeatedly performed every predetermined short time.

  This abnormality processing is performed by the EPS ECU 70 executing the abnormality processing program shown in the flowchart of FIG. This program is started in step S10 of FIG. 11, and in the next step S12, the abnormality flag IFLG is first set to “0” which is a default value. Next, the process proceeds to S14, and it is determined whether or not the EPS unit 23 has an abnormality. This determination is made based on factors such as whether an abnormality has occurred in the operating state of each sensor connected to the EPS ECU 70 or whether the EPS electric motor 232 has failed. For example, by comparing the vehicle speed V and the acceleration G, it is determined whether or not the vehicle speed sensor 61 is operating normally based on the correlation between the two values. Further, by comparing the steering torque T, the steering angle θ, the front wheel turning angle δf, the acceleration G, and the motor rotation angle θm with each other, the steering torque sensor 62, the steering angle sensor 63, It is determined whether or not the front wheel turning angle sensor 64, the acceleration sensor 65, and the motor rotation angle sensor 66 are operating normally. In addition, the abnormality is determined based on whether the detected value deviates from the range that can be normally taken by these sensors or whether the EPS electric motor 232 is not operated by the current specified by the EPS drive circuit 68. You can also If the determination in S14 is No, that is, if it is determined that there is no abnormality in the EPS unit 23, the process proceeds to S30 and the execution of this program is terminated. If the determination in S14 is No, it means that the EPS unit 23 or the electric control device is normal, so that the operation state of the EPS unit 23 is maintained in the normal state, and the EPS unit 23 continues the steering assist by the assist torque Ta. .

  If the determination in S14 is Yes, that is, if it is determined that there is an abnormality in the EPS unit 23 or the electric control device, the process proceeds to S16. In S16, the EPS ECU 70 stops the driving of the EPS electric motor 232 and shifts the operation state of the EPS unit 23 from the normal state to the assist stop state. That is, the EPS ECU 70 controls the EPS drive circuit 68 to cut off the power supply to the EPS electric motor 232. As a result, the driving of the EPS electric motor 232 is stopped and the assist torque Ta is not generated. Thereafter, the EPS ECU 70 proceeds to S18. In the state where the electric power supply to the EPS electric motor 232 is cut off as described above, the EPS electric motor 232 is free to rotate with the rotation of the steering main shaft 21, that is, the turning operation of the steering handle 10 by the driver. Rotate (turn around).

  In S18, the EPS ECU 70 performs a vehicle stop notification process to notify the driver that the EPS unit 23 has stopped assisting and to stop the vehicle. Specifically, the EPS ECU 70 operates the display unit 711 to turn on a warning lamp, for example, and display a message indicating that the assist stop state has been entered in the display panel. In addition, the EPS ECU 70 operates the audio output unit 712 to output, for example, an alarm sound from the speaker, and output from the speaker a message indicating that the assist stop state has been entered. Further, the EPS ECU 70 uses the display unit 711 and the audio output unit 712 of the alarm device 71 to prompt the driver to stop the vehicle safely. Then, when the EPS ECU 70 prompts a safe stop of the vehicle, the process proceeds to the next S20.

  In S20, the EPS ECU 70 determines whether or not the vehicle is stopped, that is, whether or not the vehicle speed V detected by the vehicle speed sensor 61 is zero. If the determination result is Yes, that is, if the vehicle speed V is 0, the process proceeds to the next S22. On the other hand, if the determination result is No, that is, if the vehicle speed V is not 0, the driver is notified to return to S18 and stop the vehicle.

  After the vehicle stops, the EPS ECU 70 controls the solenoid drive circuit 67 to supply power to the solenoid 27 in S22, and retracts the solenoid pin 272 from the groove 222a of the lower tube 222. Accordingly, the upper tube 221 can move in the axial direction with respect to the lower tube 222 beyond the stroke range restricted by the groove 222a. That is, the range of the telescopic adjustment stroke is changed from the range L regulated by the groove 222a to the range L1 regulated by the telescopic long hole 24a.

  The EPS ECU 70 proceeds to S24 after retracting the solenoid pin 272 and uses the display unit 711 and the audio output unit 712 of the alarm device 71 to urge the driver to pull out the steering handle 10 toward the passenger compartment. (Steering handle pull-out notification). That is, the EPS ECU 70 operates the display unit 711 to display, for example, a message prompting the steering handle 10 to be pulled out in the display panel, or operates the audio output unit 712 to pull out the steering handle 10 from the speaker. Output a message to urge you. Based on these notifications, when the driver operates the operation lever 252 to bring the steering column 20 into the unlocked state and pulls out the steering handle 10 toward the passenger compartment, the steering main shaft 21 extends (specifically, The upper shaft 211 moves axially toward the vehicle rear side with respect to the lower shaft 212), and the sun gear (male spline teeth) 211 a of the upper shaft 211 connected to the steering handle 10 extends in the axial direction of the upper shaft 211. Therefore, it is displaced to the vehicle rear side.

  The EPS ECU 70 proceeds to S26 after performing the steering handle pull-out notification process in S24, and determines whether or not the steering handle 10 has been pulled out to the passenger compartment side, that is, the telescopic operation is performed to the maximum stroke (stroke end). It is determined whether or not it has been done. Here, the telescopic adjustment stroke range when the solenoid pin 272 is retracted is a range L1 represented by the length of the telescopic long hole 24a in the column axis direction. Therefore, this determination can be made by detecting whether or not the locking shaft 251 is engaged with the left end in FIGS. 3 and 4 of the telescopic elongated hole 24a. This detection can be performed, for example, by arranging a proximity sensor or the like in the vicinity of the left end of the telescopic elongated hole 24a in FIGS. 3 and 4 and detecting whether the locking shaft 251 is detected by this proximity sensor. If the determination result in S26 is No, the driver is notified to return to S24 and pull out the steering wheel 10 again. If the determination result in S26 is Yes, the process proceeds to S28.

  Here, the determination of S26 being “Yes” means that the steering handle 10 has been pulled out to the vehicle compartment side by the telescopic operation. FIG. 7 is a side cross-sectional view of the steering column 20 when the steering handle 10 is pulled out to the maximum in the vehicle compartment side (when the locking shaft 251 is engaged with the left end in FIG. 3 of the telescopic elongated hole 24a). 8 is an enlarged cross-sectional view of the vicinity of the overlapping portion of the upper tube 221 and the lower tube 222 in FIG. 7, FIG. 9 is a cross-sectional view along AA in FIG. 7, and FIG. 10 is a cross-sectional view along BB in FIG. As can be seen from these drawings, when the steering handle 10 is pulled out to the maximum in the passenger compartment, the engagement between the sun gear (male spline teeth) 211a of the upper shaft 211 and the female spline teeth 212a of the lower shaft 212 is released. Thus, the sun gear 211a meshes with the planetary gear 281 disposed on the tip side of the lower shaft 212. That is, with the extension of the steering main shaft 21 by the telescopic operation, the sun gear 211a shifts from the meshing state with the female spline teeth 212a to the meshing state with the planetary gear 281, and the arrangement state of the upper shaft 211 and the lower shaft 212 is Transition from normal arrangement to deceleration arrangement.

  In the present embodiment, as described above, the sun gear 211a and the planetary gear 281 are engaged with each other when the steering handle 10 is pulled out to the maximum in the vehicle compartment side (that is, in a decelerating arrangement). And the planetary gear 281 are arranged. However, the arrangement relationship between the two gears 211a and 281 is determined so that the two gears 211a and 281 are engaged with each other by pulling out the steering handle 10 by a predetermined amount without pushing the steering handle 10 to the maximum or by pushing the steering handle 10 out of the passenger compartment. Also good. However, as described in the present embodiment, by engaging the two gears 211a and 281 at the stroke end of the telescopic adjustment stroke, the driver pulls out the steering handle 10 to engage the two gears 211a and 281. Since there is no need to adjust the amount or the push-in amount, the driver can easily perform an operation for shifting the arrangement state of the upper shaft 211 and the lower shaft 212 from the normal arrangement to the deceleration arrangement.

  When the arrangement state of the upper shaft 211 and the lower shaft 212 is a deceleration arrangement, the rotation of the upper shaft 211 accompanying the turning operation of the steering handle 10 is transmitted from the sun gear 211 a to the planetary gear 281. The planetary gear 281 also meshes with the ring gear 222b, but does not rotate because the ring gear 222b is fixed. Therefore, the planetary gear 281 to which the rotational force is transmitted from the sun gear 211a rotates while revolving around the sun gear 211a. Since the planetary gear 281 is connected to the carrier 212b and the lower shaft 212 forming the carrier 212b via the pins 282, the lower shaft 212 rotates around its axis in conjunction with the revolution of the planetary gear 281. At this time, if the number of teeth of the sun gear 211a is Ns and the number of teeth of the ring gear 222b is Nr, the reduction ratio α, which is the ratio of the rotational speed of the upper shaft 211 to the rotational speed of the lower shaft 212, is (Ns + Nr) / Ns. Is represented by Since the reduction ratio α is larger than 1, the rotation of the upper shaft 211 is decelerated by the reduction device 28 and transmitted to the lower shaft 212.

  After the arrangement state of the upper shaft 211 and the lower shaft 212 is decelerated, the EPS ECU 70 sets the abnormality flag IFLG to “1” in S28. Thereafter, the process proceeds to S30 and the execution of this program is terminated. Note that once the abnormality flag IFLG becomes “1”, the execution of this program can be stopped until the abnormality is cured.

  As described above, according to the steering device of the present embodiment, the EPS ECU 70 determines whether the EPS unit 23 or the electric control device is abnormal by executing the abnormality processing program, and if the abnormality is abnormal, the driver pulls out the steering handle 10. As a result, the arrangement of the upper shaft 211 and the lower shaft 212 is reduced. As a result, the rotation of the upper shaft 211 accompanying the steering operation of the steering handle 10 is decelerated and the rotational torque increases. Due to this increase in rotational torque, the driver can steer the left and right front wheels FW1, FW2 relatively easily even in the assist stop state.

  If the assist stop state is set, the abnormality flag IFLG is set to “1” in S28 in the abnormality process. For this reason, when the ARS ECU 91 executes the ARS reverse phase control program shown in FIG. 12, a control mode different from the control mode when the EPS unit 23 is in the normal state (normal rear wheel reverse phase control mode) is selected. take. Specifically, when the EPS unit 23 is in the assist stop state, the ARS ECU 91 determines whether or not the vehicle speed V is less than V0 in S52 of the ARS reverse phase control program shown in FIG. If there is, the rear wheel target turning angle δrn * is calculated in the next S54. This target turning angle δrn * is the same value as the target turning angle δrn * calculated when the EPS unit 23 is in the normal state. Thereafter, the process proceeds to S56, and it is determined whether or not the abnormality flag IFLG is 0. Since IFLG is “1” in the assist stop state, the determination result is No. If the determination result in S56 is No, the process proceeds to S60.

  In S60, the ARS ECU 91 calculates the target turning angle δra * of the left and right rear wheels RW1, RW2 when the EPS unit 23 is in the assist stop state. This target turning angle δra * is set according to the turning angle δf of the left and right front wheels FW1 and FW2 or the steering angle θ of the steering handle 10, and the absolute value of the target turning angle δra * is the reverse phase of the normal rear wheel at the same steering angle θ. The value is larger than the absolute value of the target turning angle δrn * set in the control mode. Thereafter, the ARS ECU 91 proceeds to S62, and drives and controls the ARS electric motor 81 so that the left and right rear wheels RW1, RW2 become the target turning angle δra * based on the detected turning angle δr of the left and right rear wheels RW1, RW2. . As a result, the left and right rear wheels RW1, RW2 are set to the target turning angle δra *. Thereafter, the process proceeds to S64, and the execution of this program is terminated. By such reverse phase control, the left and right rear wheels RW1, RW2 are steered in the direction opposite to the steered direction of the left and right front wheels FW1, FW2, and the turning radius of the vehicle is reduced.

  As described above, when the arrangement relationship between the upper shaft 211 and the lower shaft 212 is a deceleration arrangement and the EPS unit 23 is in the assist stop state, the ARS ECU 91 performs S52, S54, S56 in the ARS reverse phase control program of FIG. , S60, S62 are executed to set the target turning angle of the left and right rear wheels RW1, RW2 to δra *. This target turning angle δra * corresponds to the rear wheel turning angle during deceleration in the present invention. Further, the reverse phase control mode in which the target turning angle is δra * is the rear wheel reverse phase control mode during deceleration. In the deceleration rear wheel reverse phase control mode, the assist of steering of the steering handle 10 by the EPS unit 23 is stopped, and the rotation of the steering handle 10 and the upper shaft 211 is decelerated (that is, rotated) via the reduction gear 28. The torque is increased) and transmitted to the lower shaft 212, and further transmitted to the left and right front wheels FW1 and FW2 via the EPS unit 23, the intermediate shaft 30, the pinion shaft 40, and the rack bar 50.

  Here, when the rear wheel reverse phase control is in the normal rear wheel reverse phase control mode, the steering state of the left and right front and rear wheels, and when the rear wheel reverse phase control is in the deceleration rear wheel reverse phase control mode The steered state of the left and right front and rear wheels is compared based on FIG. As shown in FIG. 13, when the reverse-phase control mode of the rear wheels is the normal-phase reverse-phase control mode, when the driver steers the steering wheel 10 to a predetermined steering angle θ1, the left and right front wheels FW1, FW2 It is assumed that the turning angle is δfn, and the target turning angle of the left and right rear wheels RW1, RW2 calculated at that time is δrn *. (See FIG. 13 (a)). Further, when the reverse-phase control mode of the rear wheels is the reverse-phase control mode during deceleration, when the driver steers the steering handle 10 to the predetermined steering angle θ1, the turning angles of the left and right front wheels FW1, FW2 are δfa It is assumed that the target turning angle of the left and right rear wheels RW1, RW2 calculated at that time is δra *. δfa becomes an angle smaller than δfn because the rotation of the steering wheel 10 is decelerated by the reduction device 28 and transmitted to the left and right front wheels FW1, FW2. Also, δra * is set such that its absolute value | δra * | is larger than the absolute value | δrn * | of δrn *. That is, the target turning angle δra * of the left and right rear wheels RW1, RW2 with respect to the steering angle of the steering wheel 10 in the rear wheel reverse phase control mode during deceleration is the same steering angle of the steering handle 10 in the normal rear wheel reverse phase control mode. Is set to be larger than the target turning angle δrn * of the left and right rear wheels RW1, RW2.

  When the reverse-phase control mode for the rear wheels is the reverse-phase control mode for deceleration, the arrangement of the upper shaft 211 and the lower shaft 212 is a deceleration arrangement as described above. In this case, since the rotation of the steering handle 10 and the upper shaft 211 is decelerated by the speed reducer 28, the amount of steering of the left and right front wheels FW1, FW2 is reduced. On the other hand, when the reverse phase control mode of the rear wheel is the normal phase control mode, the arrangement of the upper shaft 211 and the lower shaft 212 is the normal arrangement. In this case, the rotation of the steering handle 10 and the upper shaft 211 is not decelerated by the decelerator 28. Therefore, focusing only on the steering of the front wheels, the turning radius of the vehicle in the deceleration arrangement when the steering angle is the same is larger than the turning radius of the vehicle in the normal arrangement. For this reason, in order to turn the vehicle at the time of deceleration arrangement as in the case of normal arrangement, the amount of rotation (rotation angle) of the steering handle 10 must be increased. Getting worse. On the other hand, in the steering device of the present embodiment, when the rear wheel is in the decelerating arrangement and the reverse-phase control mode of the rear wheel is the reverse-phase control mode during deceleration, the absolute value of the target turning angle of the rear wheel | δra By setting * | to a larger angle than the absolute value | δrn * | of the target turning angle set in the normal rear wheel reverse phase control mode when the steering angle is the same (θ1) An increase in the steering amount of the handle 10 is suppressed. That is, in the rear-wheel reverse phase control mode during deceleration, the left and right front wheels FW1, FW1 are reduced by decelerating the turning operation of the steering handle 10 by increasing the turning amount (steering angle) of the left and right rear wheels RW1, RW2. This compensates for a decrease in the turning amount (steering angle) of FW2. Accordingly, in the case of the deceleration arrangement, the left and right rear wheels RW1 and RW2 steer large, so that the driver increases the steering amount (number of hands) of the steering handle 10 so that the left and right front wheels FW1 and FW2 are steered. Even without this, the vehicle can be turned at a desired turning radius.

  It is possible to appropriately determine how much the target turning angle δra * in the rear wheel reverse phase control mode during deceleration is set to be larger than the target turning angle δrn * in the normal rear wheel reverse phase control mode. In this case, when the ARS ECU 91 of the rear wheel steering control device 9 performs the steering control of the left and right rear wheels RW1 and RW2 in the deceleration rear wheel reverse phase control mode, The rear wheel steering device 8 may be controlled so as to be equal to the turning radius of the vehicle when the rear wheel steering device 8 is controlled in the rear wheel reverse phase control mode. For example, as shown in FIG. 13, in the normal rear wheel reverse phase control mode, the turning radius of the vehicle when the steering angle θ1, the front wheel turning angle δfn, and the rear wheel target turning angle δrn * is rn. When the vehicle turning radius is ra when the steering angle θ1, the front wheel turning angle δfa, and the rear wheel target turning angle δra * in the deceleration rear wheel reverse phase control mode, ra = rn. It is better to set δra *.

  As described above, according to the steering device of the present embodiment, the ARS ECU 91 of the rear wheel steering control device 9 can rotate the left and right rear wheels RW1 and RW2 when the upper shaft 211 and the lower shaft 212 are in the normal arrangement. The steering angle is a steering direction that is opposite to the steering direction of the left and right front wheels FW1 and FW2, and is a steering angle that is set according to the steering angle of the left and right front wheels FW1 and FW2 or the steering angle of the steering handle 10. The normal rear wheel reverse phase control mode in which the left and right rear wheels RW1 and RW2 are steered by controlling the rear wheel steering device 8 so that the hour rear wheel reverse phase turning angle δrn * is obtained, the upper shaft 211 and the lower shaft When 212 is a decelerating arrangement, the turning angle of the left and right rear wheels RW1, RW2 is the turning direction opposite to the turning direction of the left and right front wheels FW1, FW2, and the turning angle or steering of the left and right front wheels FW1, FW2 Han Deceleration that is a turning angle that is set according to the steering angle of the steering wheel 10 and that is a turning angle that is larger than the normal-phase rear wheel reverse phase turning angle δrn * when the steering angle of the steering handle 10 is the same. There is a decelerating rear-wheel reverse phase control mode in which the rear-wheel steering device 8 is controlled to control the steering of the left and right rear wheels RW1 and RW2 so that the hour-rear wheel reverse-phase steering angle δra *. Therefore, the decrease in the front wheel turning amount in the case of the deceleration arrangement can be compensated by increasing the reverse phase turning amount of the rear wheel, and the desired vehicle can be obtained without increasing the steering amount of the steering handle 10. A turn can be made. Therefore, it is possible to provide a vehicle steering apparatus in which an increase in the steering amount is suppressed even during the deceleration arrangement.

  The front wheel steering apparatus 1 includes an EPS unit 23 that is connected to the lower shaft 212 and generates assisting force (assist torque) for assisting steering of the steering handle 10, and the ARS ECU 91 is in a normal arrangement. Further, when the EPS unit 23 is in a normal state in which the steering handle 10 is assisted by the assisting force, the rear wheel steering device 8 is controlled in the normal rear wheel reverse phase control mode, and the EPS unit 23 is in a decelerating arrangement and the EPS unit. The rear wheel steering device 8 is controlled by the rear wheel reverse phase control mode during deceleration when 23 is in an assist stop state in which steering of the steering wheel 10 is not assisted by the assist force. For this reason, in the assist stop state, the steering load that increases due to the stop of the steering assist (assist) by the EPS unit 23 is transmitted to the lower shaft 212 as the rotational torque of the upper shaft 211 is increased by the operation of the reduction gear 28. Is supplemented by In addition, the rotation of the upper shaft 211 is decelerated by the operation of the speed reducer 28 and transmitted to the lower shaft 212. This reduces the amount of front wheel steering, which is a significant increase in Complemented by reverse phase steering. For this reason, it can be set as a steering device with favorable operativity.

  Further, when the ARS ECU 91 controls the rear wheel steering device 8 in the deceleration rear wheel reverse phase control mode to control the steering of the left and right rear wheels RW1, RW2, the steering angle of the steering handle 10 is the same. The EPS unit 23 is normally controlled by turning the rear wheel steering device 8 so as to be equal to the turning radius of the vehicle when the left and right rear wheels RW1 and RW2 are steered in the normal rear wheel reverse phase control mode. The turning radius of the vehicle with respect to the steering angle of the steering wheel 10 is the same in the case of the state and the case of the assist stop state. For this reason, the driver can steer the vehicle in the same manner as in the normal state even in the assist stop state.

1 is a schematic view showing an entire vehicle steering apparatus according to an embodiment of the present invention. 1 is a schematic side view showing a state in which a steering column according to an embodiment of the present invention is attached to a vehicle. It is side surface sectional drawing of the steering column which concerns on embodiment of this invention. FIG. 4 is an enlarged cross-sectional view showing the vicinity of an overlapping region between an upper tube and a lower tube in the steering column shown in FIG. 3. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG. It is side surface sectional drawing of a steering column when the sun gear and the planetary gear are meshing | engaging in embodiment of this invention. FIG. 8 is an enlarged cross-sectional view showing the vicinity of an overlapping region between an upper tube and a lower tube in the steering column shown in FIG. 7. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG. It is a flowchart of the abnormality processing program which ECU for EPS in embodiment of this invention performs. It is a flowchart of the reverse phase control program which ECU for ARS performs in the embodiment of the present invention. It is the figure in the embodiment of the present invention which compares the state of the vehicle at the time of the normal time rear wheel reverse phase control mode and the state of the vehicle at the time of the rear wheel reverse phase control mode at the time of deceleration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Front wheel steering apparatus, 10 ... Steering handle, 20 ... Steering column, 21 ... Steering main shaft, 211 ... Upper shaft (first shaft), 211a ... Male spline teeth (sun gear), 212 ... Lower shaft (second shaft) ), 212a ... Female spline teeth, 212b ... Carrier, 22 ... Column tube, 221 ... Upper tube, 222 ... Lower tube, 222b ... Ring gear, 23 ... EPS unit (auxiliary force applying means), 232 ... Electric motor for EPS, 233 ... input shaft, 234 ... output shaft, 27 ... solenoid, 28 ... speed reducer, 281 ... planetary gear, 282 ... pin, 61 ... vehicle speed sensor, 62 ... steering torque sensor, 63 ... steering angle sensor, 64 ... front wheel steering Angle sensor, 70 ... EPS ECU (assisting force applying means), 71 ... Alarm 8 ... Rear wheel steering device, 81 ... ARS electric motor, 82 ... Rear wheel steering shaft, 83 ... Ball screw mechanism, 9 ... Rear wheel steering control device, 91 ... ARS ECU, 92 ... ARS drive circuit, 93 ... Rear wheel turning angle sensor, FW1, FW2 ... left and right front wheels, RW1, RW2 ... left and right rear wheels, δrn * ... target turning angle (normal rear wheel reverse phase turning angle), δra * ... target turning angle (during deceleration) Rear wheel reverse phase steering angle)

Claims (3)

A second shaft connected to the steering handle and rotating integrally with the steering handle; and a second shaft connected to the first shaft and rotated by transmitting the rotation of the first shaft; A front wheel steering device that steers the front wheel according to the amount of rotation of the shaft;
A rear wheel steering device capable of steering the rear wheels;
In a vehicle steering apparatus comprising: a rear wheel steering control device that performs steering control of rear wheels by controlling the rear wheel steering device;
The front wheel turning device has a reduction device that decelerates the rotation of the first shaft and transmits it to the second shaft,
The first shaft and the second shaft are arranged so that the rotation of the first shaft is transmitted to the second shaft without going through the speed reduction device, and the first shaft through the speed reduction device. It is arranged to be able to take a deceleration arrangement arranged so that the rotation of the shaft is transmitted to the second shaft,
In the rear wheel steering control device, when the first axis and the second axis are in the normal arrangement, the steering angle of the rear wheel is a steering direction opposite to the steering direction of the front wheel, and the front wheel A normal rear wheel reverse phase control mode for controlling the rear wheel steering device so as to obtain a normal rear wheel reverse phase turning angle that is a turning angle set according to a steering angle or a steering angle of a steering wheel; When the first shaft and the second shaft are in the decelerating arrangement, the turning angle of the rear wheel is a turning direction opposite to the turning direction of the front wheel and the turning angle of the front wheel or the steering handle Rear wheel reverse phase during deceleration, which is a turning angle set in accordance with the steering angle and the steering angle is larger than the normal rear wheel reverse phase steering angle when the steering wheel has the same steering angle. A vehicle having a decelerating rear-wheel reverse phase control mode for controlling the rear-wheel steering device so as to have a turning angle. Of the steering apparatus. The vehicle steering apparatus according to claim 1,
The front wheel steering device includes an auxiliary force application unit that is connected to the second shaft and generates an auxiliary force for assisting the steering of the steering wheel.
The rear wheel steering control device has the normal arrangement and the normal force rear wheel reverse phase control mode when the auxiliary force applying means is in a normal state in which the steering force is assisted by the auxiliary force. When the rear wheel turning device is in an assist stop state in which the rear wheel steering device is controlled and the speed reduction arrangement is performed and the auxiliary force applying means does not assist the steering of the steering wheel by the auxiliary force, A vehicle steering apparatus that controls the rear wheel steering apparatus. The vehicle steering apparatus according to claim 2,
When the rear wheel steering control device controls the rear wheel steering device in the deceleration rear wheel reverse phase control mode and the steering wheel has the same steering angle, the normal rear wheel reverse phase control mode is used. So that the turning radius of the vehicle when the rear wheel steering device is controlled and the turning radius of the vehicle when the rear wheel steering device is controlled in the rear wheel reverse phase control mode during deceleration are equal to each other. A vehicle steering apparatus, characterized by controlling a rear wheel steering apparatus.

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