JP2009143390A - Vehicular steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow turning wheels to turn in a state that rotation of a transmission shaft is locked along with change of reduction ratio in a vehicular steering device. <P>SOLUTION: A transmission mechanism CM provided for the vehicular steering device is equipped with a planetary gear mechanism 90 and an output gear 12a, and rotation of an upper shaft 11 is transmitted to a lower shaft 12 at the same or decreased rotation speed. A ring gear 93 of the planetary gear mechanism 90 is attached to a lower tube 22 on a vehicle-body side via a tolerance ring 94 as a rotation-allowing member. By this, in a state that a sun gear 91 is engaged with both the output gear 12a and a planetary gear 95, the ring gear 93 can rotate by inputting steering torque not less than a predetermined torque set beforehand via the shaft 11. Accordingly, integrally rotating the shafts 11, 12 can make the turning wheels turn. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steering means operated by a driver, a transmission shaft for connecting the steering means and a steered wheel and transmitting a steering force input via the steering means to the steered wheel, and the transmission shaft The present invention relates to a vehicle steering apparatus including an auxiliary force applying unit that is connected to the vehicle and applies a predetermined auxiliary force to the operation of the steering unit.

  2. Description of the Related Art Conventionally, a vehicle steering apparatus provided with auxiliary force applying means (for example, an electric motor) for reducing a steering force necessary for operating a steering means (for example, a steering wheel) by a driver is well known. For example, in Patent Document 1 below, detection torque is taken in from detection means operating normally among detection means for estimating a plurality of steering states, and the assist torque by the electric motor is monitored while monitoring the read detection information. An electric power steering control device that reduces the application of the power is shown. According to this conventional electric power steering control device, it is possible to prevent a sudden decrease in assist torque due to the stop of the electric motor, so that a good steering feeling is ensured.

Further, Patent Document 2 below discloses a ball screw rack assist type electric power steering device that improves operability. According to this conventional rack-assist type electric power steering device, a torque limiter is provided between the ball nut and the power transmission element that transmits the rotational driving force of the electric motor. Even if there is, excessive rotational torque can be prevented from acting on each component member, and smooth movement of the rack shaft is ensured.
JP 2005-67262 A Japanese Patent Laid-Open No. 2004-9882

  By the way, even in the conventional electric power steering control device shown in Patent Document 1 and the conventional electric power steering device shown in Patent Document 2, after the operation of the electric motor is completely stopped, the assist is performed. Torque (auxiliary force) is not applied. For this reason, in order for the driver to rotate the steering means (steering handle), a large steering force (for example, steering torque) is required, which imposes a physical burden on the driver. 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 the situation where the assist torque is applied to the above-described problem (the normal state where the auxiliary force applying means applies the auxiliary force), the rotation of the first shaft that can be rotated by the operating force from the steering means is made the same speed. Thus, in a situation where the assist torque is not applied by the steering force transmitted from the first shaft and the assist torque is not applied (the assist force application stop state in which the assist force applying means does not apply the assist force), the first By providing a speed change mechanism that decelerates the rotation of the shaft and transmits it to the second shaft, even when the assist torque is not applied, the steering means can be easily rotated by only the steering force input by the driver via the steering means. Is possible.

  By the way, the transmission mechanism includes a ring gear fixed to the vehicle body so as not to rotate, and a sun gear that is provided coaxially and integrally with the first shaft and is movable in the axial direction along with the axial movement of the first shaft. And a carrier that is coaxially and integrally provided on the second shaft, and is rotatably assembled to the carrier so as to mesh with the ring gear and mesh with the sun gear as the sun gear moves in the axial direction. When a planetary gear mechanism having a meshable planetary gear and an output gear that is coaxially and integrally provided on the second shaft and that can mesh and disengage with the sun gear by the axial movement of the sun gear are provided. In the auxiliary force application stop state in which the auxiliary force applying means does not apply the auxiliary force, it is necessary that the sun gear surely moves in the axial direction and meshes with the planetary gear of the planetary gear mechanism.

  That is, in the transmission mechanism, the reduction ratio is different between when the sun gear meshes with the output gear and when the sun gear meshes with the planet gear. For this reason, there is a possibility that the sun gear meshes with both the output gear and the planet gear depending on the axial movement of the sun gear. In this case, the vehicle is in a state where the rotation of the first shaft and the second shaft is locked. There is a risk of driving.

  The present invention has been made to cope with the above-described problem by enabling the steered wheels to be steered even in a state where the rotation of the transmission shaft is locked in accordance with the change in the reduction ratio. A steering means operated by the transmission means, a transmission shaft for connecting the steering means and the steered wheels to transmit the steering force input via the steering means to the steered wheels, and the steering connected to the transmission shaft. In the vehicle steering apparatus including the auxiliary force applying means for applying a predetermined auxiliary force to the operation of the means, the transmission shaft is disposed on the steering means side and is rotatable by the steering force from the steering means. The first shaft and the shift mechanism disposed on the steered wheel side so as to be movable in the axial direction and capable of transmitting the rotation of the first shaft at the same speed or by decelerating the transmission. Can be rotated by the steering force transmitted from the first shaft The transmission mechanism includes a ring gear provided on the vehicle body side, and is provided coaxially and integrally with the first shaft, and is axially moved along with the axial movement of the first shaft. A movable sun gear, a carrier that is coaxially and integrally provided on the second shaft, and an assembly that is rotatably engaged with the carrier and meshed with the ring gear. Accordingly, a planetary gear mechanism having a planetary gear that can mesh with or disengage from the sun gear, and an output that is coaxially and integrally provided on the second shaft and that can mesh with or disengage from the sun gear by axial movement of the sun gear. The ring gear is preliminarily provided with torque input from the planetary gear when the sun gear meshes with both the output gear and the planetary gear. It is characterized in that provided on the vehicle body side via a rotation allowing member that allows relative rotation with respect to the vehicle body of the ring gear when the above predetermined torque that is.

  In this case, the predetermined torque is a torque larger than a torque required to steer the steered wheels that is input through the steering means when at least the sun gear meshes only with the planetary gear. It is good to set to.

  In this case, the rotation permission member is disposed, for example, between the inner peripheral surface of the column tube that is non-rotatably assembled on the vehicle body side and the outer peripheral surface of the ring gear accommodated in the column tube. The column tube of the ring gear is applied when a torque less than the predetermined torque is input by applying an elastic force to the inner peripheral surface of the column tube and the outer peripheral surface of the ring gear. A tolerance ring that prohibits relative rotation of the ring gear and allows the ring gear to rotate relative to the column tube when a torque greater than the predetermined torque is input.

  In these vehicle steering devices, the rotation of the first shaft is caused by the speed change mechanism in a normal state (normal time) in which the auxiliary force applying means applies a predetermined auxiliary force (assist torque) to the operation of the steering means. A state where the gear is transmitted to the second shaft at the same speed, more specifically, a sun gear (coaxially and integrally provided on the first shaft) is output gear (coaxially and integrally on the second shaft). Provided). For this reason, the driver turns the steered wheels in a state in which the speed change mechanism transmits the rotation of the first shaft to the second shaft at the same speed, and the auxiliary force applying means applies the auxiliary force to the transmission shaft. Can do.

  On the other hand, in the auxiliary force application stop state (when the assist is stopped) in which the auxiliary force applying unit does not apply a predetermined auxiliary force to the operation of the steering unit, the rotation of the first shaft is decelerated by the speed change mechanism to the second shaft. The state of transmission, more specifically, the state in which the sun gear meshes with the planetary gear and does not mesh with the output gear. For this reason, the driver can steer the steered wheels in a state where the speed change mechanism decelerates the rotation of the first shaft and transmits it to the second shaft, and the auxiliary force applying means does not apply the auxiliary force to the transmission shaft. The steering force necessary for turning the steered wheels can be reduced by the speed change mechanism. Therefore, even when the auxiliary force applying means is in the auxiliary force applying stop state, the driver can easily turn the steered wheels by turning the steering means with only the steering force input via the steering means. Thus, good steering performance can be ensured.

  By the way, in these vehicle steering apparatuses, there is a possibility that the sun gear meshes with both the output gear and the planetary gear in the transition from the normal state to the assist stop state or the transition from the assist stop state to the normal state. However, when such a situation occurs, the ring gear constituting the speed change mechanism is provided on the vehicle body side via a rotation allowing member (for example, a tolerance ring). The first shaft and the second shaft can be integrally rotated by inputting a torque equal to or greater than a predetermined torque. Therefore, the driver can steer the steered wheels although the steering force increases even when the sun gear meshes with both the output gear and the planetary gear.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show an embodiment of a vehicle steering apparatus according to the present invention. As shown in FIG. 1, the steering apparatus of this embodiment is a steering means that is turned by a driver. A steering handle SH, and a transmission shaft (transmission mechanism) CO that connects the steering handle SH and left and right front wheels FW1 and FW2 as steered wheels are provided.

  As shown in FIGS. 1 and 2, the steering handle SH is for transmitting a steering force input by the driver to the transmission shaft CO, and is connected to the driver side end of the transmission shaft CO. Yes. The transmission shaft CO is used to transmit the steering force input via the steering handle SH to the left and right front wheels FW1 and FW2, and the steering main shaft 10 in the steering column SC and the upper universal joint to the steering main shaft 10 An intermediate shaft 32 connected via a pin 31, a pinion shaft 34 connected to the intermediate shaft 32 via a lower universal joint 33, and a pinion gear 35 and a rack gear 36 connected to the pinion shaft 34. The rack bar 37 is connected to the left and right ends of the rack bar 37 and the knuckles (not shown) attached to the left and right front wheels FW1 and FW2 via ball joints (not shown). That a pair of left and right tie rods 38L, and a 38R.

  The steering column SC includes a steering main shaft 10 that can rotate integrally with the steering handle SH, a column tube 20 that accommodates and rotatably supports the steering main shaft 10, and a tilting operation (up and down) of the steering column SC. In the telescopic adjustment stroke of the steering column SC (stroke L shown in FIGS. 3 and 4) and the lock mechanism 40 that allows or restricts the telescopic operation (extension / contraction operation in the column axis direction) and the telescopic operation (the stroke L shown in FIGS. 3 and 4). A solenoid 50 that allows movement at the telescopic adjustment stroke and allows or restricts movement outside the telescopic adjustment stroke, and an EPS (electric power steering) unit as auxiliary force applying means for applying a predetermined auxiliary force to the operation of the steering handle SH 60.

  As shown in FIGS. 1 to 3, the steering main shaft 10 includes an upper shaft 11 as a first axis and a lower shaft 12 as a second axis, and a torsion bar (not shown) on the lower shaft 12. And an output shaft 13 connected to each other. The upper shaft 11 is formed in a hollow shape, and is connected to the steering handle SH on the upper end side (driver side), and can rotate integrally with the steering handle SH by a turning operation of the steering handle SH. . The lower shaft 12 is formed in a hollow shape, and a lower end portion of the upper shaft 11 is inserted so as to be slidable in the column axis direction.

  As shown in FIGS. 1 to 3, the column tube 20 is for rotatably supporting the steering main shaft 10, and the front side of the vehicle is below the steering support member SS provided in the instrument panel reinforcement IR. The upper tube 21 and the lower tube 22 are provided. The instrument panel reinforcement IR and the steering support member SS are vehicle body side members that are assembled and fixed to the vehicle body.

  As shown in FIGS. 2 and 3, the upper tube 21 is attached to the lower rear portion of the steering support member SS via the movable bracket 23 and the locking mechanism 40 that are integrally fixed to the outer periphery of the lower front portion of the upper tube 21. The fixed bracket SB is assembled so as to be movable in the vertical direction and the column axis direction. The lock mechanism 40 is capable of coupling / releasing (locking / unlocking) the movable bracket 23 and the fixed bracket SB.

  For this reason, when the lock mechanism 40 is locked, the movable bracket 23 is fixed (coupled) to the fixed bracket SB so as not to move, and when the lock mechanism 40 is unlocked, the above-described fixing is performed. Is released, and the movable bracket 23 is movable with respect to the fixed bracket SB. As shown in FIGS. 3 and 4, a telescopic guide 24 for reducing sliding resistance with the outer periphery of the lower tube 22 is fixed to the inner periphery of the lower end portion of the upper tube 21.

  Further, as shown in FIG. 3, the upper tube 21 is formed in a hollow shape, and the upper shaft 11 can be rotated and integrated via a bearing Br provided integrally on the inner periphery of the upper end portion. Is supported to be movable in the column axis direction. The upper tube 21 and the telescopic guide 24 are formed with insertion long holes 21a and 24a which are long in the column axis direction for inserting the eccentric cam 43 of the lock mechanism 40, and the solenoid pin 52 of the solenoid 50 is inserted. Through holes 21b and 24b are formed.

  As shown in FIG. 2, the lower tube 22 can be pivoted in the vertical direction on the arm SSa provided at the front lower part of the steering support member SS via the housing 61 of the EPS unit 60 and the support pin P1 ( The support pin P1 is supported on the axis center (tilt center). As shown in FIG. 3, the lower tube 22 is formed in a hollow shape, and can rotate the lower shaft 12 via a bearing (not shown) provided integrally on the inner periphery of the lower end portion. It is supported so that it cannot be displaced in the column axis direction.

  The lower tube 22 is inserted into the lower end portion (vehicle front portion) of the upper tube 21 at the upper end portion (vehicle rear portion), and supports the upper tube 21 so as to be slidable in the column axial direction. . A column that defines a telescopic adjustment stroke L by the contact of the solenoid pin 52 of the solenoid 50 so that the solenoid pin 52 can enter and retract above the portion of the lower tube 22 that is inserted into the upper tube 21. A long regulation groove 22a is formed in the axial direction.

  As shown in FIGS. 1 and 2, the intermediate shaft 32 is connected to the upper universal joint 31 at the upper end portion (vehicle rear portion) and is connected to the lower universal joint 33 at the lower end portion (vehicle front portion). The output shaft 13 is connected to the output shaft 13 via the upper universal joint 31 so as to be integrally rotatable. The intermediate shaft 32 can be contracted in the column axial direction in order to prevent the steering column SC and the steering handle SH from being pushed out to the driver side in the event of a vehicle collision.

  As shown in FIG. 1, the pinion shaft 34 is connected to the intermediate shaft 32 via the lower universal joint 33 at the upper end portion (vehicle rear portion) so as to be integrally rotatable, and the lower end portion (vehicle front portion). Is integrally provided with a pinion gear 35. The rack bar 37 is provided with a plate-like rack gear 36 that meshes with the pinion gear 35 at an intermediate portion, and is connected so as to be able to transmit the rotation of the pinion gear 35. When the rotation of the pinion gear 35 is transmitted, the rack bar 37 is axially moved. It can be displaced in the left-right direction in FIG.

  The pair of left and right tie rods 38L, 38R is connected to each end of the rack bar 37 at one end via a ball joint (not shown) and left and right at the other end via a ball joint (not shown). It is connected to a knuckle (not shown) that pivotally supports the front wheels FW1, FW2. Accordingly, the left and right front wheels FW1 and FW2 can be steered to the left and right by the displacement of the rack bar 37 in the left and right direction in FIG.

  The lock mechanism 40 is a well-known one, and a tilt slot (not shown) provided in the fixed bracket SB (an arc-shaped slot having the tilt center as a center) and a telescopic length extending in the column axis direction provided in the movable bracket 23. A shaft (bolt) 41 that extends through the hole 23a (see FIGS. 3 and 4) and extends in the left-right direction of the vehicle, a nut (not shown) that is screwed to the vehicle right end of the shaft 41, and the vehicle of the shaft 41 An operation lever 42 (see FIGS. 1 and 2) assembled to the left end so as to be integrally rotatable, a lock cam unit (not shown) assembled on the shaft 41 between the fixing bracket SB and the operation lever 42; An eccentric cam 43 or the like is provided on the outer periphery of the intermediate portion of the shaft 41 so as to be integrally rotatable.

  The lock cam unit (not shown) increases the frictional engagement force between the fixed bracket SB and the movable bracket 23 by the rotation of the operation lever 42 in the counterclockwise direction in FIG. 2, and the rotation of the operation lever 42 in the clockwise direction in FIG. The frictional engagement force between the fixed bracket SB and the movable bracket 23 is reduced. The eccentric cam 43 is engaged with the lower outer periphery of the lower tube 22 by the rotation of the shaft 41 in the counterclockwise direction in FIG. 3 as the operation lever 42 rotates in the counterclockwise direction in FIG. The shaft 41 is configured to be detached from the outer periphery of the lower portion of the lower tube 22 by rotating the shaft 41 in the clockwise direction in FIG.

  Therefore, in this lock mechanism 40, the operation lever 42 is rotated to the lock position in the counterclockwise direction of FIG. 2 to be locked, and the steering column SC can be tilted (the axis of the support pin P1). (Tilting operation around (tilt center)) and telescopic operation (movement of the upper shaft 11 and the upper tube 21 in the column axis direction with respect to the lower shaft 12 and the lower tube 22) can be restricted, and the operation lever 42 2 is rotated to the unlock position in the clockwise direction in FIG. 2 to be in the unlocked state, and the tilting operation and telescopic operation of the steering column SC can be allowed. When the lock mechanism 40 is in the unlocked state, the spring 25 interposed between the fixed bracket SB and the eccentric cam 43 elastically restricts the downward movement of the steering column SC.

  As shown in FIG. 3, the solenoid 50 includes a solenoid body 51 that is assembled to the upper surface of the upper tube 21 on the front side of the vehicle, and a solenoid pin 52 that is assembled in the solenoid body 51 so as to advance and retreat. I have. The solenoid main body 51 retracts the solenoid pin 52 against the biasing force of the spring by energizing the spring (not shown) for energizing the solenoid pin 52 into the specified groove 22a (the lower side in FIG. 3). A coil (not shown) for attracting in the direction (upper side in FIG. 3) is provided.

  When the solenoid pin 52 is in the state shown in FIG. 3, a part (lower end portion) of the solenoid pin 52 enters the specified groove 22 a formed in the lower tube 22 by the biasing force of the spring of the solenoid body 51, and the telescopic adjustment stroke. The movement in the column axis direction within L is allowed, and the movement in the column axis direction outside the telescopic adjustment stroke L is restricted. The solenoid pin 52 is partially retracted from the specified groove 22a of the lower tube 22 when the coil of the solenoid body 51 is energized, and allows the column axial movement outside the telescopic adjustment stroke L.

  The EPS unit 60 is for applying an assist torque Ta (auxiliary force) to the steering main shaft 10 in order to reduce the steering torque t input when the driver rotates the steering handle SH. As shown in FIG. 2, a housing 61 connected to the lower end (front end of the vehicle) of the lower tube 22 by fastening means such as a bolt, an electric motor 62 assembled to the housing 61, and the electric motor 62 Is provided with a reduction gear (not shown). The electric motor 62 is connected to the output shaft 13 of the steering main shaft 10 via a speed reducer, and can be rotationally driven by energization to apply the assist torque Ta to the output shaft 13 of the steering main shaft 10.

  Next, the electric control device 70 that controls the operation of the solenoid 50 and the operation of the EPS unit 60 (electric motor 62) and the alarm device 80 connected to the electric control device 70 will be described. As shown in FIG. 1, the electronic control unit 70 includes a vehicle speed sensor 71, a steering torque sensor 72, a steering angle sensor 73, a turning angle sensor 74, an acceleration sensor 75, and a motor rotation angle sensor 76. An electronic control unit 77 connected to each sensor, a drive circuit 78 for operating the solenoid 50, and a drive circuit 79 for operating the electric motor 62 are provided.

  The vehicle speed sensor 71 detects and outputs the vehicle speed V of the vehicle. The steering torque sensor 72 is assembled in the housing 61 of the EPS unit 60 and is input to the input portion of the EPS unit 60 from the steering handle SH via the upper shaft 11 and the lower shaft 12 of the steering main shaft 10. Torque t is detected and output. The steering angle sensor 73 is assembled to the upper tube 21 corresponding to the upper shaft 11, detects the rotation angle of the steering handle SH, and outputs it as the steering angle θ. The turning angle sensor 74 is assembled in the rack housing 39 corresponding to the rack bar 37, detects the amount of displacement of the rack bar 37 in the axial direction, and the left and right front wheels FW1, corresponding to the detected displacement amount. The turning angle δ of FW2 is output. The acceleration sensor 75 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 76 is assembled, for example, in the motor housing of the electric motor 62, detects the rotation angle of the motor rotation shaft, and outputs it as the motor rotation angle θm.

  The electronic control unit 77 has a microcomputer composed of a CPU, ROM, RAM, timer, and the like as main components, and is based on the correlation between the detected values of the sensors 71 to 76 that are input. When it is determined whether the operation state of 76 is normal or abnormal, and it is determined that the operation state of each sensor 71 to 76 is normal, a normal program (not shown) is executed, and the operation of each sensor 71 to 76 is performed. When it is determined that the state is abnormal, an abnormal program (not shown) is executed.

  When executing the normal program, the electronic control unit 77 determines the assist torque Ta based on the V detected by the vehicle speed sensor 71 and the steering torque t detected by the steering torque sensor 72, and the determined assist torque Ta is set to the determined assist torque Ta. Correspondingly, a drive current for driving the electric motor 62 is supplied to the drive circuit 79. As a result, the electric motor 62 is supplied with a drive current from the drive circuit 79 and is driven to rotate, so that an appropriate assist torque Ta is applied to the output shaft 13 of the steering main shaft 10 (hereinafter referred to as an assist normal state). .

  Further, when executing the normal program, the electronic control unit 77 does not supply a drive current for driving the solenoid 50 to the drive circuit 78. As a result, the solenoid 50 defines a telescopic adjustment stroke L by causing a part of the solenoid pin 52 to enter the defining groove 22a formed in the lower tube 22, as shown in FIG. Therefore, in the assist normal state, the driver can adjust the column axial position of the steering wheel SH within the range of the telescopic adjustment stroke L. Further, the electronic control unit 77 outputs a normal signal to the alarm device 80 when executing the normal program.

  On the other hand, when executing the abnormality program, the electronic control unit 77 stops driving the electric motor 62 and therefore does not supply a drive current to the drive circuit 79. As a result, the electric motor 62 is not supplied with a drive current from the drive circuit 79, and the assist torque Ta is not applied to the output shaft 13 of the steering main shaft 10 (hereinafter referred to as an assist stop state).

  Further, when executing the abnormality program, the electronic control unit 77 supplies a drive current for retracting a part (lower end portion) of the solenoid pin 52 of the solenoid 50 from the specified groove 22a of the lower tube 22 to the drive circuit 78. . As a result, the solenoid 50 is supplied with a drive current from the drive circuit 78 and retracts a part of the solenoid pin 52 into the solenoid body 51 as shown in FIG. Accordingly, in the assist stop state, the regulation of the telescopic adjustment stroke L due to the contact of the solenoid pin 52 is released, so that the driver can move the upper tube 21 to a position where the upper tube 21 contacts the eccentric cam 43 of the lock mechanism 40 by a predetermined amount ( The insertion long holes 21a and 24a can be moved in the column axis direction). Further, the electronic control unit 77 outputs an abnormality signal to the alarm device 80 when executing the abnormality program.

  The alarm device 80 is for informing the driver that the assist is in the normal assist state or the assist stop state, and is connected to the electronic control unit 77 and is visible to the driver (for example, in the meter cluster). Etc.) and an audio output unit 82 for outputting audio. The display unit 81 includes, for example, a lamp, a display panel, and the like, and notifies the driver of the assist normal state or the assist stop state by lighting the lamp or switching the display panel. The voice output unit 82 includes, for example, a speaker, and notifies the driver of the assist stop state by outputting voice. In this alarm device 80, when a normal signal is input from the electronic control unit 77, the display unit 81 notifies the driver of the assist normal state. When an abnormal signal is input from the electronic control unit 77, the display unit 81 notifies the driver of the assist stop state, and the voice output unit 82 notifies the driver of the assist stop state.

  By the way, in this embodiment, as shown in FIGS. 3 and 4, a transmission mechanism CM capable of transmitting the rotation of the upper shaft 11 to the lower shaft 12 at the same speed or by decelerating the rotation is provided on the steering column SC. ing.

  The speed change mechanism CM has a planetary gear mechanism 90 having a sun gear 91 provided on the upper shaft 11 as an input element, a carrier 92 provided on the lower shaft 12 as an output element, and a ring gear 93 provided on the lower tube 22 as a reaction force element. And an output gear 12 a provided on the lower shaft 12.

  The planetary gear mechanism 90 includes the sun gear 91, the carrier 92, and the ring gear 93 described above, and also includes a planetary gear 95 assembled to the carrier 92. In this planetary gear mechanism 90, a plurality of planetary gears 95 (for example, three) are arranged at regular intervals in the circumferential direction.

  The sun gear 91 is coaxially and integrally formed on the outer periphery of the vehicle front end portion (the left end portion in the drawing) of the upper shaft 11, and can move in the column axis direction as the upper shaft 11 moves in the column axis direction. The carrier 92 is coaxially and integrally provided at the vehicle rear end portion of the lower shaft 12. The ring gear 93 has teeth formed on the inner periphery thereof, and is accommodated at the vehicle rear end portion of the lower tube 22 via a tolerance ring 94 as a rotation allowing member.

  As shown in FIGS. 3 to 5, the tolerance ring 94 has protrusions 94 a and 94 b protruding radially outward and inward sequentially in the circumferential direction, that is, the circumferential cross-sectional shape is corrugated. It is formed and disposed between the inner peripheral surface of the lower tube 22 and the outer peripheral surface of the ring gear 93. The tolerance ring 94 disposed between the inner peripheral surface of the lower tube 22 and the outer peripheral surface of the ring gear 93 has protrusions 94a and 94b having the inner peripheral surface of the lower tube 22 and the outer periphery of the ring gear 93, respectively. For example, it is assembled in a state compressed in the radial direction so as to give a resilient force to the surface.

  As described above, the protrusions 94 a and 94 b generate frictional forces between the inner peripheral surface of the lower tube 22 and the outer peripheral surface of the ring gear 93 by being assembled so as to impart elastic force. Therefore, the tolerance ring 94 prohibits the relative rotation of the ring gear 93 with respect to the lower tube 22 by the generated frictional force in a state where torque less than a predetermined torque set in advance is applied to the ring gear 93. Can do. On the other hand, the tolerance ring 94 rotates relative to the lower tube 22 of the ring gear 93 against the generated frictional force in a state where a torque greater than a predetermined torque set in advance is applied to the ring gear 93. Can be tolerated. Here, as the predetermined torque set in advance, for example, at least when the rotation of the upper shaft 11 is decelerated and transmitted to the lower shaft 12 in the assist stop state, the steering handle SH is rotated to turn the left and right front wheels FW1. , FW2 may be set to a torque larger than the steering torque t required for turning. In this case, for example, when the rotation of the upper shaft 11 is transmitted to the lower shaft 12 at the same speed when the assist is stopped, the steering wheel SH is operated to rotate the left and right front wheels FW1 and FW2 in the assist stop state. You may implement by setting to a torque larger than the steering torque t required in order to steer.

  As shown in FIGS. 3 and 4, the planetary gear 95 can rotate integrally with a support shaft 95a provided at the shaft center, and two pairs of sliding bearings 95b are provided at the front and rear portions of the support shaft 95a. It is assembled. These sliding bearings 95 b support the support shaft 95 a so as to freely rotate, and are assembled to the carrier 92. As described above, the planetary gear 95 assembled to the carrier 92 is always in mesh with the ring gear 93 as shown in FIGS. 3 to 5, and the sun gear 91 is moved in the column axial direction by the sun gear 91. And can be engaged / disengaged.

  The output gear 12a is coaxially and integrally formed on the inner periphery of the rear portion (the left portion in the drawing) of the lower shaft 12, and can be engaged / disengaged with the sun gear 91 by the movement of the sun gear 91 in the column axis direction. is there. For this reason, in this speed change mechanism CM, when the telescopic operation is performed within the range of the telescopic adjustment stroke L (for example, at the position shown in FIG. 3), the sun gear 91 meshes with the output gear 12a and the planetary gear 95 The non-engaged state is maintained, and the rotation of the upper shaft 11 (first axis) is transmitted to the lower shaft 12 (second axis) at the same speed. Further, when the sun gear 91 is telescopically operated out of the range of the telescopic adjustment stroke L (for example, when moved to the position shown in FIG. 4), the sun gear 91 meshes with the planetary gear 95 and the output gear 12a. In an unengaged state, the rotation of the upper shaft 11 (first axis) is decelerated by the planetary gear mechanism 90 and transmitted to the lower shaft 12 (second axis).

  In the steering apparatus of the embodiment configured as described above, when in the assist normal state, a part of the solenoid pin 52 enters the specified groove portion 22a of the lower tube 22 as shown in FIG. For this reason, the driver can perform a telescopic operation in the range of the telescopic adjustment stroke L by setting the lock mechanism 40 to the unlocked state.

  In the telescopic operation in the assist normal state, as shown in FIG. 3, the state in which the sun gear 91 is engaged with the output gear 12a and is not engaged with the planetary gear 95 is maintained, and the upper shaft 11 is rotated at the same speed. And transmitted to the lower shaft 12. For this reason, the driver transmits the rotation of the upper shaft 11 to the lower shaft 12 at the same speed, and the EPS unit 60 applies the assist torque Ta to the output shaft 13 of the steering main shaft 10 in the state where The left and right front wheels FW1, FW2 (steered wheels) can be steered.

  On the other hand, in the assist stop state, as shown in FIG. 4, a part of the solenoid pin 52 is retracted from the specified groove 22 a of the lower tube 22. For this reason, the driver can perform a telescopic operation outside the telescopic adjustment stroke L by setting the lock mechanism 40 to the unlocked state.

  In the telescopic operation in the assist stop state, the driver is prompted by the display unit 81 and the audio output unit 82 of the alarm device 80 to stabilize the traveling behavior of the vehicle (for example, the vehicle stops at a vehicle speed of zero). ), The lock mechanism 40 is unlocked and the steering wheel SH is pulled out to the driver side. As a result, the sun gear 91 moves to the driver side with the movement of the upper shaft 11, and meshes with the planetary gear 95 and does not mesh with the output gear 12 a.

  Accordingly, the rotation of the upper shaft 11 is decelerated and transmitted to the lower shaft 12 by the sun gear input-carrier output planetary gear mechanism 90, and the driver steers the left and right front wheels (steered wheels) FW1, FW2. The steering force (steering torque t) required for the operation can be reduced. Therefore, even in the assist stop state, the driver can easily steer the wheels FW1 and FW2 with only the steering force input via the steering handle SH, and can ensure good steering performance. It is.

  By the way, as shown in FIG. 5, when the sun gear 91 is maintained in mesh with both the output gear 12a and the planetary gear 93 (meshed with two gears having different reduction ratios), the upper shaft 11 cannot rotate. It becomes a locked state. In this locked state, the tolerance ring 94 allows the ring gear 93 to rotate relative to the lower tube 22 when the driver inputs a steering torque t larger than a predetermined torque via the steering handle SH. That is, in this case, the tolerance ring 94 allows the relative rotation of the ring gear 93, so that the rotation of the upper shaft 11 can be transmitted to the lower shaft 12 at the same speed. For this reason, although the driver needs to input a large steering torque t, the driver can steer the left and right front wheels FW1, FW2 (steered wheels) while avoiding the locked state.

  The implementation of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention.

  For example, in the above-described embodiment, the planetary gear 95 and the accompanying structural members (support shaft 95a, sliding bearing 95b) are provided in three (three sets), but the number of these may be changed as appropriate. It is also possible to carry out.

  In the embodiment described above, the sun gear 91 meshes with the output gear 12a by the driver pulling the steering handle SH toward the passenger compartment (moving the upper shaft 11 to the right in the drawing with respect to the lower shaft 12). However, the driver pushes the steering handle (SH) from the driver side (the upper shaft 11 is pushed against the lower shaft 12). It is also possible to implement the configuration by switching from the state in which the sun gear (91) is engaged with the output gear (12a) to the state in which it is engaged with the planetary gear (95). It is. In this case, the layout in which the driver side is in the order of the output gear (12a) and the planetary gear (95) is arranged so that the driver side is in the order of the planetary gear (95) and the output gear (12a). It is necessary to lay out.

  In the embodiment described above, the steering main shaft 10 is an EPS unit (auxiliary force applying means) that is connected to the transmission shaft CO and applies a predetermined assist torque Ta (auxiliary force) to the operation of the steering wheel SH. This is implemented using a column-assist type electric power steering device that applies assist torque Ta to the output shaft 13. For example, a pinion-assist type electric power steering device that applies assist torque Ta to the pinion shaft 34. It is also possible to carry out using a rack assist type electric power steering device that applies an assist torque Ta to the rack bar 37.

  In the above-described embodiment, the electric power steering device is used as the auxiliary force applying means for applying a predetermined auxiliary force to the operation of the steering handle SH. However, the hydraulic power steering device is used. It is also possible to carry out. In the above-described embodiment, the rack and pinion type steering gear is used as the steering gear in the transmission shaft CO. However, for example, a ball and screw type steering gear may be used. It is.

  Further, in the above-described embodiment, the present invention is implemented in a vehicle steering apparatus including a manual tilt / telescopic mechanism in which the driver can manually adjust the position of the steering handle SH in the vertical direction and the column axis direction. However, since the present invention is implemented in the telescopic mechanism portion, the present invention can also be implemented in a vehicle steering apparatus that includes a telescopic mechanism and does not include a tilt mechanism in the same manner as in the above-described embodiment or with appropriate modifications. is there.

  Further, in the above-described embodiment, the present invention is implemented in a vehicle steering apparatus having a manual tilt / telescopic mechanism. However, an electric drive unit (an electric motor with a speed reducer and an electric drive unit that operates and stops by a switch operation by a driver). And a screw feed mechanism that is driven by this, and a steering for a vehicle having an electric tilt and telescopic mechanism capable of adjusting the position of the steering handle (SH) in the vertical direction and the column axis direction. It is possible to implement the present invention in an apparatus.

  Further, in the above embodiment, the tolerance ring 94 is adopted as the rotation allowing member. However, the ring gear 93 is prohibited from rotating relative to the lower tube 22 with a steering torque t less than a predetermined torque, and a predetermined torque is applied. Any member that allows relative rotation of the ring gear 93 with a steering torque t greater than the torque, in other words, any member that functions as a torque limiter can be used as the rotation-permitting member.

1 is an overall configuration diagram schematically showing an embodiment of a vehicle steering apparatus according to the present invention. FIG. 2 is a side view showing a relationship among a steering column, an upper universal joint, an intermediate shaft, and a lower universal joint shown in FIG. 1. FIG. 3 is a partially enlarged vertical side view for explaining the configuration of the steering column shown in FIG. 2. It is an operation explanatory view explaining the state where the sun gear in FIG. 3 meshes with the planetary gear. FIG. 4 is an operation explanatory view partially enlarged to explain a state in which the sun gear in FIG. 3 meshes with both the output shaft and the planetary gear.

Explanation of symbols

SH ... steering handle, FW1, FW2 ... front wheel, CO ... transmission shaft, SC ... steering column, SK ... spiral cable, 10 ... steering main shaft, 11 ... upper shaft, 12 ... lower shaft, 12a ... output gear, 20 ... Column tube, 21 ... Upper tube, 22 ... Lower tube, 23 ... Movable bracket, 24 ... Telescopic guide, 25 ... Spring, Br ... Bearing, SB ... Fixed bracket, 31 ... Upper universal joint, 32 ... Intermediate shaft, 33 ... Lower universal joint, 34 ... pinion shaft, 35 ... pinion gear, 36 ... rack gear, 37 ... rack bar, 38R, 38L ... tie rod, 40 ... lock mechanism, 41 ... shaft, 42 ... operating lever, 43 ... eccentric lock , 50 ... EPS unit, 51 ... Housing, 52 ... Electric motor, 60 ... Steering lock mechanism, 61 ... Lock holder, 62 ... Lock bar, IG ... Ignition switch, K ... Key cylinder, 70 ... Electronic control unit, 71 ... Vehicle speed Sensor: 72 ... Steering torque sensor, 73 ... Steering angle sensor, 74 ... Steering angle sensor, 75 ... Motor rotation angle sensor, 76 ... Electronic control unit, 77 ... Drive circuit, CM ... Transmission mechanism, 90 ... Planetary gear mechanism, 91 ... Sun gear, 92 ... Carrier, 93 ... Ring gear, 94 ... Tolerance ring, 95 ... Planetary gear

Claims (3)

A steering means operated by a driver, a transmission shaft for connecting the steering means and the steered wheels and transmitting a steering force input via the steering means to the steered wheels, and connected to the transmission shaft. In a vehicle steering apparatus comprising: an auxiliary force applying unit that applies a predetermined auxiliary force to the operation of the steering unit;
The transmission shaft is disposed on the steering unit side and is rotatable by a steering force from the steering unit, and the transmission shaft is disposed on the steered wheel side and accommodates the first shaft so as to be movable in the axial direction. A second shaft rotatable by a steering force transmitted from the first shaft via a transmission mechanism capable of transmitting rotation of the first shaft at the same speed or reduced speed;
A ring gear provided on a vehicle body side; a sun gear provided coaxially and integrally with the first shaft and movable in the axial direction along with the axial movement of the first shaft; A carrier that is coaxially and integrally provided on the second shaft, and that is rotatably assembled to the carrier and meshed with the ring gear, and meshed with the sun gear as the sun gear moves in the axial direction. A planetary gear mechanism having a planetary gear that can be disengaged, and an output gear that is coaxially and integrally provided on the second shaft and that can mesh and disengage with the sun gear by axial movement of the sun gear,
The ring gear is configured so that the sun gear is engaged with both the output gear and the planetary gear, and the torque input from the planetary gear is greater than or equal to a predetermined torque that is set in advance. A vehicle steering apparatus, wherein the vehicle steering apparatus is provided on a vehicle body side via a rotation allowing member that allows relative rotation. The predetermined torque is
2. The torque according to claim 1, wherein at least the sun gear is engaged with only the planetary gear, and is set to a torque larger than a torque that is input via the steering means and is required to steer the steered wheels. Vehicle steering device. The rotation allowing member is
An inner peripheral surface of the column tube and the ring are disposed between an inner peripheral surface of the column tube assembled non-rotatably on the vehicle body side and an outer peripheral surface of the ring gear accommodated in the column tube. By applying a resilient force to the outer peripheral surface of the gear, when a torque less than the predetermined torque is input, relative rotation of the ring gear with respect to the column tube is prohibited, and the torque exceeds the predetermined torque. The vehicle steering device according to claim 1, wherein the tolerance ring is a tolerance ring that allows a relative rotation of the ring gear with respect to the column tube when a torque of 1 is input.

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