JP2007203826A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress affect due to a load transmitted from a wheel through a steering shaft during stop of a vehicle with a low power consumption. <P>SOLUTION: In a steering device 80A, a steering lock mechanism 20 locks the rotation of the steering shaft 14 connected to a steering wheel 12. A transmission ratio variable unit 22 generates the differential in the rotational direction between the steering shaft 14 and an output shaft 15 converted into a turning of a front wheel 54. After the steering shaft 14 is locked by the steering lock mechanism 20, the transmission ratio variable unit 22 relatively drives to rotate the steering shaft 14 and the output shaft 15 so that the torque applied on the steering shaft 14 or the output shaft 15 is reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steering device, and more particularly to a steering device including a transmission ratio variable unit.

  The vehicle is provided with a steering lock mechanism that locks the rotation of the steering wheel to prevent theft. The steering wheel is connected to a steering unit that steers the wheel via a steering shaft, and a steering lock mechanism is usually provided on the steering shaft. For example, if one of the front wheels to be steered is on a curb while being steered, or if the front wheel is steered in the left turn direction when parked downhill, An external force is applied in the steering direction. This external force is transmitted to the steering lock mechanism via the steering shaft, and a load is applied to the steering lock mechanism. As described above, when a load is applied to the steering lock mechanism, it becomes difficult to improve the smoothness of the lock.

For this reason, in Patent Document 1, for example, immediately after the ignition key is inserted, an electric motor that assists the turning operation of the handle is operated to turn the steering shaft, thereby assisting the extraction of the lock bar from the lock groove. An electric power steering device has been proposed. For example, Patent Document 2 proposes a vehicle steering lock device that starts control of an electric power steering device when a key detection signal is input from a sensor that detects key insertion. For example, Patent Document 3 proposes a steering device in which a steering wheel is moved to a predetermined position by driving an actuator when a preset driving condition occurs.
JP 2001-171534 A JP 2002-211141 A JP-A-9-202250

  For example, when the technique proposed in the above-mentioned patent document is applied to smoothly release the steering lock when one of the front wheels is on a curb or the like while being steered as described above, the electric power steering device further increases the curb. The wheel must be steered in the direction to get on. For this reason, the power consumption by the electric power steering apparatus becomes large.

  The present invention has been made in view of these problems, and an object of the present invention is to suppress the influence of a load transmitted from a wheel via a steering shaft while the vehicle is stopped with low power consumption.

  In order to solve the above-described problems, a steering device according to an aspect of the present invention is connected to a steering lock mechanism that locks rotation of a steering shaft that is coupled to a steering wheel, a steering shaft, and a steering unit that steers wheels. A transmission ratio variable unit that generates a differential in the rotational direction between the output shaft and the output shaft. The transmission ratio variable unit has a rotational direction differential between the steering shaft and the output shaft so that torque applied to the steering shaft or the output shaft is reduced when the steering shaft is locked by the steering lock mechanism. generate.

  According to this aspect, since the differential is generated so that the torque applied to the steering shaft or the output shaft is reduced, the influence of the force transmitted from the wheel on the lock mechanism or the like can be suppressed with low power consumption. it can. In addition, since the torque applied to the steering shaft or the output shaft before releasing the lock can be reduced, it is possible to prevent a load from being applied to the lock mechanism or the like for a long period of time.

  The variable transmission ratio unit rotates between the steering shaft and the output shaft by operating an actuator so that a torque applied to the steering shaft or the output shaft is reduced when the steering shaft is locked by the steering lock mechanism. A directional differential may be generated. According to this aspect, it is possible to reliably reduce the torque applied to the steering shaft or the output shaft.

  The transmission ratio variable unit is disposed between the steering shaft and the output shaft by releasing the differential regulation in the rotational direction between the steering shaft and the output shaft in a state where the steering shaft is locked by the steering lock mechanism. A differential in the rotational direction may be generated. According to this aspect, it is possible to reduce a load applied to the lock mechanism or the like by a simple control of canceling the differential restriction.

  The transmission ratio variable unit reduces the torque applied to the steering shaft or the output shaft when a torque larger than a predetermined torque is applied to the steering shaft or the output shaft while the steering shaft is locked by the steering lock mechanism. As described above, a differential in the rotational direction may be generated between the steering shaft and the output shaft. According to this aspect, when the torque applied to the steering shaft or the output shaft is low, the opportunity for generating a differential in the rotational direction between the steering shaft and the output shaft can be reduced, thereby reducing power consumption. be able to.

  According to the steering device of the present invention, it is possible to suppress the influence of the load transmitted from the wheels via the steering shaft while the vehicle is stopped with low power consumption.

  Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is an overall configuration diagram of a steering system 10A according to the first embodiment. The steering system 10A is a system that converts the rotation of the steering wheel 12 into the steering of the front wheels 54 in the vehicle. This figure is a view of the steering system 10A as viewed from the top to the bottom of the vehicle. The steering system 10A includes a steering device 80A and a steering unit 40.

  The steering device 80A includes a steering wheel 12, a steering shaft 14, a steering angle sensor 16, an ignition sensor 18, a steering lock mechanism 20, an output shaft 15, a torque sensor 24, an electric power steering mechanism 32, a connecting shaft 17, and a transmission ratio variable unit ECU. (ECU: electronic control unit) 100 and EPSECU (EPS: Electric Power Steering) 150.

  The steering wheel 12 is provided in the vehicle compartment and is rotated by the driver. One end of the steering shaft 14 is coupled to the steering wheel 12 so as to rotate together with the steering wheel 12.

  The steering angle sensor 16 is provided on the steering shaft 14 and detects the steering angle and steering direction of the steering wheel 12. The steering angle sensor 16 is connected to the transmission ratio variable unit ECU100 and EPSECU150. The detection result of the steering angle sensor 16 is output to the transmission ratio variable unit ECU100 and EPSECU150.

  The ignition sensor 18 detects an on / off operation of the ignition key by the user. The ignition sensor 18 is connected to the transmission ratio variable unit ECU100 and EPSECU150. The detection result of the ignition sensor 18 is output to the transmission ratio variable unit ECU100 and EPSECU150.

  The steering lock mechanism 20 has a lock bar (not shown) and a lock holder (not shown). The lock holder is provided in an annular shape, and is fitted and fixed coaxially to the steering shaft 14. A plurality of teeth that protrude outward in the radial direction are formed on the outer periphery of the lock holder. The lock bar is formed in a rod shape or a flat plate shape, and is connected to a key cylinder into which a vehicle key is inserted.

  When the user rotates the key cylinder together with the key to a position where the ignition key is turned off, the lock bar advances between the teeth of the lock holder. When the steering wheel 12 is rotated in this state, the side surface of the lock bar comes into contact with the side surface of the tooth portion of the lock holder. For this reason, the rotation of the steering wheel 12 is restricted by the steering lock mechanism 20 while the ignition key is turned off.

  When the key is inserted into the key cylinder and the key cylinder is rotated to the position where the ignition key is turned on together with the key, the lock bar is retracted from between the teeth of the lock holder. For this reason, while the ignition key is on, the restriction on the rotation of the steering wheel 12 by the steering lock mechanism 20 is released.

  The transmission ratio variable unit 22 has a differential generation mechanism and a differential lock mechanism which will be described later. The transmission ratio variable unit 22 is provided on the steering unit side (to be described later) of the steering lock mechanism 20 and is connected to the other end of the steering shaft 14 and one end of the output shaft 15 that are arranged coaxially. The differential generation mechanism includes a motor (not shown), a wave generator (not shown), a flex spline (not shown), a driven gear (not shown), and a stator gear (not shown).

  The wave generator is composed of a plug (not shown) and a flexible bearing (not shown). The plug is formed in a plate shape having an elliptical outer periphery. The center of the elliptical shape of the plug is fixed to the motor shaft. A flexible bearing having flexibility is attached to the outer periphery of the plug. The driven gear and the stator gear are formed as internal teeth having the same pitch circle and different number of teeth. The stator gear is connected to the steering shaft 14 so as to rotate together with the steering shaft 14. The driven gear is connected to the output shaft 15 so as to rotate together with the output shaft 15. The driven gear and the stator gear are provided adjacent to each other coaxially.

  The flexspline is formed into a cylindrical shape by a flexible material. The flexspline has a gear portion as external teeth on the outer periphery. The flexspline is disposed inside the driven gear and the stator gear. The wave generator is placed inside a cylindrical flexspline. By disposing the wave generator inside the flexspline, a part of the flexspline is bent, and a part of the flexspline gear meshes with a part of the stator gear and the driven gear. When the wave generator is driven by the motor in this state, the portion where the flexspline gear meshes with the stator gear and the driven gear moves in the circumferential direction. As described above, since the number of teeth is different between the stator gear and the driven gear, a differential in the rotational direction is generated between the steering shaft 14 and the output shaft 15. As described above, the differential generation mechanism functions as an actuator that generates a differential in the rotational direction between the steering shaft 14 and the output shaft 15.

  The differential lock mechanism includes a solenoid (not shown), a lock pin (not shown), and a lock holder (not shown). The lock holder is formed in an annular shape, and is fitted and fixed to the motor shaft of the transmission ratio variable unit 22. A plurality of teeth that protrude outward in the radial direction are formed on the outer periphery of the lock holder. The lock bar is formed in a bar shape or a flat plate shape and is connected to a solenoid. When the solenoid is activated, the lock pin advances between the teeth of the lock holder, and the rotation of the motor shaft is restricted. The differential lock mechanism thus regulates the differential between the steering shaft 14 and the output shaft 15. When the operation of the solenoid is stopped, the lock pin is retracted from between the teeth of the lock holder by the biasing force of the spring, and the restriction on the rotation of the motor shaft is released. The differential lock mechanism thus releases the differential restriction between the steering shaft 14 and the output shaft 15.

  When the user rotates the key cylinder together with the key to a position where the ignition key is turned off, the lock bar advances between the teeth of the lock holder. When the steering wheel 12 is rotated in this state, the side surface of the lock bar comes into contact with the side surface of the tooth portion of the lock holder. For this reason, the rotation of the steering wheel 12 is restricted by the steering lock mechanism 20 while the ignition key is turned off.

  The torque sensor 24 is provided on the output shaft 15 and detects torque applied to the output shaft 15. The torque sensor 24 is provided with a torsion bar. The torque sensor 24 detects the torque applied to the output shaft 15 by detecting the twist angle of the torsion bar. The torque sensor 24 is provided on the steering unit side of the transmission ratio variable unit 22. The torque sensor 24 is connected to the transmission ratio variable unit ECU100 and EPSECU150. The detection result of the torque sensor 24 is output to the transmission ratio variable unit ECU100 and EPSECU150.

  The electric power steering mechanism 32 is provided on the steering unit side of the torque sensor 24. The electric power steering mechanism 32 includes a motor 28, a speed reduction mechanism 26, and an angle sensor 30. The motor shaft of the motor 28 is connected to the speed reduction mechanism 26. The speed reduction mechanism 26 is provided with a gear and meshes with a gear portion provided on the output shaft 15. When the motor 28 is operated, the rotational motion is decelerated by the speed reduction mechanism 26, and the output shaft 15 is rotationally driven. The angle sensor 30 detects the rotation angle of the motor 28. The angle sensor 30 is connected to the EPS ECU 150. A detection result by the angle sensor 30 is input to the EPS ECU 150.

  The other end of the output shaft 15 is connected to one end of the connecting shaft 17 via the universal joint 34. A pinion gear (not shown) is provided at the other end of the connecting shaft 17.

  The steered unit 40 includes a gear box 44, a steering shaft 46, a tie rod 48, and a knuckle arm 50. The gear box 44 is formed in a substantially cylindrical shape, and is arranged so that the axial direction is parallel to the left-right direction of the vehicle. A steering shaft 46 is inserted into the gear box 44. The steering shaft 46 is disposed so that both ends protrude from the gear box 44. A rack gear is provided on the steering shaft 46. The pinion gear of the connecting shaft 17 and the rack gear of the steering shaft 46 mesh within the gear box 44, and the rack and pinion mechanism 42 is configured. The rack and pinion mechanism 42 converts the rotation of the steering wheel 12 into axial propulsion of the steering shaft 46.

  One end of a tie rod 48 is connected to the end of the steering shaft 46. The other end of the tie rod 48 is connected to a knuckle arm 50 that supports the front wheel 54. The knuckle arm 50 is attached to the vehicle so as to be rotatable about the king pin 52. When the steering shaft 46 is propelled in the axial direction, the knuckle arm 50 is rotated via the tie rod 48 and the front wheel 54 is steered.

  The EPS ECU 150 calculates a target assist torque for driving the output shaft 15 using the detection results of the steering angle sensor 16 and the torque sensor 24. The EPS ECU 150 outputs a control current to the drive circuit 152 so as to supply the motor 28 with a current for generating the calculated target assist torque. The drive circuit 152 supplies a current corresponding to the control current supplied from the EPS ECU 150 from the battery 90 to the motor 28 and operates the motor 28. The EPS ECU 150 assists the steering of the steering wheel 12 by the user according to the steering angle and torque as described above. The EPS ECU 150 executes steering assist control for assisting the user in steering the steering wheel 12 from when the ignition sensor 18 detects that the ignition key is turned on until it is detected that the ignition key is turned off.

  The transmission ratio variable unit ECU 100 operates the transmission ratio variable unit 22 to generate a differential in the rotational direction between the steering shaft 14 and the output shaft 15 in order to improve the operability of steering by the user. Hereinafter, the transmission ratio variable unit ECU 100 will be described in detail with reference to FIG.

  FIG. 2 is a functional block diagram of the transmission ratio variable unit ECU 100 according to the first embodiment. The transmission ratio variable unit ECU 100 includes a differential lock control unit 104, a differential control unit 106, a storage unit 108, and a timer 110. The differential lock control unit 104 controls locking of the differential generation mechanism 62 by the differential lock mechanism 60. The differential control unit 106 controls the generation of a differential between the steering shaft 14 and the output shaft 15 by the differential generation mechanism 62. The storage unit 108 stores a threshold value for elapsed time, a threshold value for torque applied to the output shaft 15, and the like. The timer 110 measures time.

  The motor of the transmission ratio variable unit 22 is provided with a rotation sensor (not shown). The rotation sensor is connected to the transmission ratio variable unit ECU 100, and the detection result of the rotation sensor is output to the transmission ratio variable unit ECU 100. The differential lock control unit 104 needs to lock the differential by the transmission ratio variable unit 22 by using the detection result of the rotation sensor, for example, a condition for determining that a failure has occurred in the transmission ratio variable unit 22. It is determined whether or not a predetermined condition that is recognized as being present is satisfied. When the detection result satisfies a predetermined condition, the differential lock control unit 104 supplies a control current to the drive circuit 102 so as to supply power to the solenoid of the differential lock mechanism 60. The drive circuit 102 supplies power to the solenoid of the differential lock mechanism 60 to lock the differential between the steering shaft 14 and the output shaft 15. For example, when a failure occurs in the transmission ratio variable unit 22, the differential between the steering shaft 14 and the output shaft 15 is locked in this way, so that the driver can reliably move the wheel with the fixed transmission ratio thereafter. It is possible to steer.

  The differential control unit 106 uses the detection results of the steering angle sensor 16, the torque sensor 24, and the wheel speed sensor 36 that detects the rotational speed of the wheel, to make a relative target between the steering shaft 14 and the output shaft 15. Calculate the differential angle. The differential control unit 106 outputs a control current to the drive circuit 102 so as to supply a current corresponding to the calculated target differential angle to the motor. The drive circuit 102 supplies a current corresponding to the supplied control current from the battery 90 to the motor. The differential control unit 106 thus generates a differential in the rotational direction between the steering shaft 14 and the output shaft 15 according to the steering angle, torque, and wheel speed.

  The transmission ratio variable unit ECU 100 generates a rotational differential between the steering shaft 14 and the output shaft 15 from when the ignition sensor 18 detects that the ignition key is turned on until it is detected that the ignition key is turned off. Execute variable transmission ratio control.

  Returning to FIG. 1, for example, when the vehicle rides on a curb or the like with one of the front wheels 54 being steered, a force in the steered direction acts on the front wheel 54. In the steering device 80A according to the present embodiment, the steering lock mechanism 20, the transmission ratio variable unit 22, the torque sensor 24, and the speed reduction mechanism 26 are arranged in this order from the steering wheel 12 toward the steering unit 40. Therefore, the force acting on the steering direction of the front wheels 54 on the steering lock mechanism 20, the transmission ratio variable unit 22, the torque sensor 24, and the electric power steering mechanism 32 disposed from the steering lock mechanism 20 to the steering unit 40. Is transmitted.

  Therefore, the force acting in the steering direction of the front wheel 54 is transmitted to the steering lock mechanism 20, and the side surface of the lock bar and the side surface of the tooth portion of the lock holder in the steering lock mechanism 20 are strongly pressed. This increases the frictional force between the side surface of the lock bar and the side surface of the tooth portion of the lock holder. In consideration of such an increase in frictional force, the use of the steering lock mechanism 20 having a strong pulling force leads to an increase in cost.

  Further, for example, when a state where one of the front wheels 54 is steered and continues on a curbstone or the like continues for a long time, a strong pressing force is applied to the side surface of the lock bar and the side surface of the tooth portion of the lock holder for a long time. When the strength of the lock bar and the lock holder is increased in consideration of such a long pressing force, the steering lock mechanism 20 is increased in size.

  The torque sensor 24 has a regulating member that regulates twisting of the torsion bar by a predetermined angle or more. When a force in the direction of steering is applied to the front wheels 54 in a state where the rotation of the steering shaft 14 is locked by the steering lock mechanism 20, a large torque is applied to the output shaft 15 of the front wheels 54. As a result, when the torsion bar is twisted by a predetermined angle, twisting of a further angle is restricted by the restricting member. Increasing the strength of the torsion bar and the regulating member in order to suppress deformation of the torsion bar and the regulating member due to this state continuing for a long time leads to an increase in the size of the torque sensor 24 and the like.

  For this reason, in the steering device 80A according to the present embodiment, the transmission ratio variable unit ECU 100 controls the steering so that the torque applied to the steering shaft or the output shaft is reduced after the steering shaft 14 is locked by the steering lock mechanism 20. The transmission ratio variable unit 22 is controlled so as to generate a differential in the rotational direction between the shaft and the output shaft. Hereinafter, this control procedure will be described in detail with reference to the flowchart of FIG.

  FIG. 3 is a flowchart showing an operation procedure of the steering device 80A according to the first embodiment. The processing in this flowchart starts when the ignition key is turned on.

  Whether the rotation of the steering shaft 14 is locked by the steering lock mechanism 20 is determined by determining whether or not the ignition key is turned off by using the detection result of the ignition sensor 18 (S11). Determine whether or not. For this reason, the ignition sensor 18 functions as a lock state detecting means for detecting whether or not the rotation of the steering shaft 14 is locked by the steering lock mechanism 20, and the transmission ratio variable unit ECU 100 is operated by the steering lock mechanism 20. It functions as a lock state determination unit that determines whether or not the rotation of 14 is locked.

  If it is determined that the ignition key is not turned off (N in S11), it is determined that the rotation of the steering shaft 14 is not locked by the steering lock mechanism 20, and the transmission ratio variable unit ECU 100 continues to turn off the ignition key. It is determined every predetermined time. When it is determined that the ignition key is turned off (Y in S11), the steering lock mechanism 20 determines that the rotation of the steering shaft 14 is locked and the vehicle is parked, and the timer 110 determines that the ignition key has been turned off. The measurement of the elapsed time t is started (S12).

When the measurement of time is started, the variable transfer ratio unit ECU100 the elapsed time every predetermined time t is determined whether reaches a predetermined time t ₁ (S13). When it is determined that the elapsed time t is smaller than the predetermined time t ₁ (N in S13), the transmission ratio variable unit ECU 100 continues to determine whether the elapsed time t has reached the predetermined time t ₁ every predetermined time. .

If the elapsed time t is determined that the predetermined time t ₁ or more (S13 of Y), the calculated torque T applied to the output shaft 15 from the detection result of the torque sensor 24. The transmission ratio variable unit ECU 100 refers to the first predetermined torque T ₁ stored in the storage unit 108 and determines whether or not the absolute value of the torque T applied to the output shaft 15 is equal to or greater than the first predetermined torque T ₁ ( S14). The first predetermined torque T _{1 at} this time has a low influence on the unlocking of the steering lock mechanism 20 and the torsion bar of the torque sensor 24 even when the predetermined time t ₁ has passed since the torque was applied. Is set.

If the absolute value of the torque T applied to the output shaft 15 is determined to be the first predetermined torque T ₁ is smaller than (S14 of N), the less necessary to reduce the torque applied to the steering lock mechanism 20 and the torque sensor 24 Therefore, the process returns to S12 again. Thus, by determining whether the torque applied to the steering lock mechanism 20 and the torque sensor 24 exceeds a predetermined value every predetermined time, the frequency of executing the process for reducing the torque is suppressed, and the power consumption is reduced. Reduced. Further, by not performing the process of reducing the torque when the predetermined value is not exceeded, the process of reducing the torque is performed when the need to reduce the torque applied to the steering lock mechanism 20 or the torque sensor 24 is low. To suppress power consumption.

If the absolute value of the torque T applied to the output shaft 15 is determined to be the first predetermined torque _{T 1} or more (S14 of Y), the variable transfer ratio unit ECU100 includes the torque applied to the steering lock mechanism 20 and the torque sensor 24 It is determined that reduction is necessary. For this reason, the torque reduction process which reduces the torque given to these is performed.

  In this torque reduction process, first, the differential control unit 106 calculates a target differential angle to be generated between the steering shaft 14 and the output shaft 15 (S15). The storage unit 108 is necessary to reduce this torque to the value given to the output shaft 15 obtained from the detection result of the torque sensor 24 and to a value that has a low effect on the steering lock mechanism 20 and the torque sensor 24. A map in which various differential angles are associated is stored. The differential control unit 106 calculates the target differential angle with reference to this map.

  The differential lock control unit 104 stops the electric power supplied to the solenoid of the differential lock mechanism 60, causes the lock pin to be retracted from the lock holder, and releases the differential lock between the steering shaft 14 and the output shaft 15. (S16). When the differential lock is released, the differential control unit 106 controls the current supplied to the differential generation mechanism 62 to generate a target angle differential between the steering shaft 14 and the output shaft 15. The differential generating mechanism 62 is operated until (S17).

When the differential to the target angle is generated, the variable transfer ratio unit ECU100 absolute value determines whether decreased to the second predetermined torque T ₂ less torque T applied to the output shaft 15 (S18). The second predetermined torque is set to a value that has a sufficiently low influence on the unlocking of the steering lock mechanism 20 and the torsion bar of the torque sensor 24 even if the torque is applied to the steering lock mechanism 20 or the torque sensor 24 for a long time. Is done. Incidentally, the second predetermined torque T ₂ may be set to zero as a matter of course.

The absolute value of the torque T applied to the output shaft 15, when it is still determined that the second larger than the predetermined torque _{T 2} (S18 of N), the program returns to the processing of S15. The variable transfer ratio unit ECU100 repeats this process until the absolute value of the torque T applied to the output shaft 15 becomes the second predetermined torque T ₂ or less.

If the absolute value of the torque T applied to the output shaft 15 is determined to be the second predetermined torque T ₂ or less (S18 of Y), the differential lock control unit 104, the difference between the steering shaft 14 and the output shaft 15 The differential lock mechanism 60 is actuated to lock the movement (S19). Thereby, the steering of the front wheel 54 is suppressed.

(Second Embodiment)
FIG. 4 is a flowchart showing an operation procedure of the steering device 80B included in the steering system 10B according to the second embodiment. The configuration of the steering system 10B according to the present embodiment and the steering device 80B included in the steering system 10B is the same as the configuration of the steering system 10A according to the first embodiment and the steering device 80A included in the steering system 10B. . The processing in this flowchart starts when the ignition key is turned on. Note that S31, S32, and S33 are the same as S11, S12, and S13 in FIG.

When it is determined that the elapsed time t is smaller than the predetermined time t ₁ (N in S33), the transmission ratio variable unit ECU 100 continues to determine whether the elapsed time t has reached the predetermined time t ₁ every predetermined time. .

If the elapsed time t is determined that the predetermined time t ₁ or more (S33 of Y), regardless of the torque applied to the steering shaft 14 or output shaft 15, the differential lock control unit 104, the solenoid of the differential lock mechanism 60 The power supplied to is stopped, the lock pin is withdrawn from the lock holder, and the differential lock between the steering shaft 14 and the output shaft 15 is released (S34). As a result, when torque is applied to the transmission ratio variable unit 22, a differential is generated between the steering shaft 14 and the output shaft 15 due to the torque and is applied to the steering lock mechanism 20 and the torque sensor 24. Torque can be reduced. For this reason, power consumption can be reduced compared with the case where the transmission ratio variable unit 22 is operated. When the differential lock is released, the differential lock control unit 104 locks the differential (S35). Thereby, the steering of the front wheel 54 is suppressed.

(Third embodiment)
FIG. 5 is an overall configuration diagram of a steering system 10C according to the third embodiment. Note that the ignition sensor 18, the transmission ratio variable unit 22, the torque sensor 24, and the electric power steering mechanism 32 constituting the steering device 80C according to the present embodiment are connected to the transmission ratio variable unit ECU100 and the EPSECU 150 in the first state. Since it is the same as that of the steering apparatus 80A according to the embodiment, the description is omitted. Further, the steered unit 40 is the same as that of the first embodiment, and the description thereof is omitted.

  As described above, in the steering device 80C according to this embodiment, the steering lock mechanism 20, the torque sensor 24, the transmission ratio variable unit 22, and the electric power steering mechanism 32 are arranged in this order from the steering wheel 12 toward the steering unit 40. Be placed. Therefore, the force acting on the steering direction of the front wheels 54 on the steering lock mechanism 20, the torque sensor 24, the transmission ratio variable unit 22, and the electric power steering mechanism 32 disposed from the steering lock mechanism 20 to the steering unit 40. Is transmitted.

  The transmission ratio variable unit ECU 100 of the steering device 80C according to the present embodiment also performs the process described in the flowchart of FIG. 3 or the flowchart of FIG. As a result, even in the steering device 80C in which the components are arranged in this order, the influence on the steering lock mechanism 20 and the torque sensor 24 due to the force acting in the steering direction of the front wheels 54 is reduced.

(Fourth embodiment)
FIG. 6 is an overall configuration diagram of a steering system 10D according to the fourth embodiment. The connection state of the ignition sensor 18, the transmission ratio variable unit 22, the torque sensor 24, and the electric power steering mechanism 32 constituting the steering device 80D according to the present embodiment to the transmission ratio variable unit ECU100 and EPSECU150 is the first state. Since it is the same as that of the steering apparatus 80A according to the embodiment, the description is omitted. Further, the steered unit 40 is the same as that of the first embodiment, and the description thereof is omitted.

  As described above, in the steering device 80D according to the present embodiment, the steering lock mechanism 20, the torque sensor 24, the electric power steering mechanism 32, and the transmission ratio variable unit 22 are arranged in this order from the steering wheel 12 toward the steering unit 40. Be placed. Therefore, the force acting on the steering direction of the front wheels 54 on the steering lock mechanism 20, the torque sensor 24, the electric power steering mechanism 32, and the transmission ratio variable unit 22 arranged from the steering lock mechanism 20 to the steering unit 40. Is transmitted.

  The transmission ratio variable unit ECU 100 of the steering device 80D according to the present embodiment also performs the process described in the flowchart of FIG. 3 or the flowchart of FIG. As a result, even in the steering device 80D in which the components are arranged in this order, the influence on the steering lock mechanism 20 and the torque sensor 24 due to the force acting in the steering direction of the front wheels 54 is reduced.

(Fifth embodiment)
FIG. 7 is an overall configuration diagram of a steering system 10E according to the fifth embodiment. The connection state of the ignition sensor 18, the transmission ratio variable unit 22, the torque sensor 24, and the electric power steering mechanism 32 constituting the steering device 80E according to the present embodiment to the transmission ratio variable unit ECU100 and EPSECU150 is the first state. Since it is the same as that of the steering apparatus 80A according to the embodiment, the description is omitted. Further, the steered unit 40 is the same as that of the first embodiment, and the description thereof is omitted.

  As described above, in the steering device 80E according to the present embodiment, the torque sensor 24, the electric power steering mechanism 32, and the transmission ratio variable unit 22 are arranged in this order from the steering wheel 12 toward the steering unit 40. The steering lock mechanism 20 locks the rotation of the speed reduction mechanism 26 of the electric power steering mechanism 32. Therefore, the force acting on the steering direction of the front wheels 54 on the steering lock mechanism 20, the speed reduction mechanism 26 of the electric power steering mechanism 32, and the transmission ratio variable unit 22 arranged from the steering lock mechanism 20 to the steering unit 40. Is transmitted.

  The transmission ratio variable unit ECU 100 of the steering device 80E according to the present embodiment also performs the processing described in the flowchart of FIG. 3 or the flowchart of FIG. As a result, even in the steering device 80E in which the components are arranged in this order, the force acting on the steering direction of the front wheels 54 has an influence on the speed reduction mechanism 26 of the steering lock mechanism 20 and the electric power steering mechanism 32. Reduced.

(Sixth embodiment)
FIG. 8 is an overall configuration diagram of a steering system 10F according to the sixth embodiment. The connection state of the ignition sensor 18, the transmission ratio variable unit 22, the torque sensor 24, and the electric power steering mechanism 32 constituting the steering device 80F according to the present embodiment to the transmission ratio variable unit ECU100 and EPSECU150 is the first state. Since it is the same as that of the steering apparatus 80A according to the embodiment, the description is omitted. Further, the steered unit 40 is the same as that of the first embodiment, and the description thereof is omitted.

  Thus, in the steering device 80F according to the present embodiment, the torque sensor 24, the electric power steering mechanism 32, the steering lock mechanism 20, and the transmission ratio variable unit 22 are arranged in this order from the steering wheel 12 toward the steering unit 40. Be placed. Accordingly, the force acting in the steering direction of the front wheels 54 is transmitted to the steering lock mechanism 20 and the transmission ratio variable unit 22 arranged from the steering lock mechanism 20 to the steering unit 40.

  The transmission ratio variable unit ECU 100 of the steering device 80F according to the present embodiment also performs the processing described in the flowchart of FIG. 3 or the flowchart of FIG. Thereby, also in the steering device 80F in which the respective components are arranged in this order, the influence on the steering lock mechanism 20 due to the force acting in the steering direction of the front wheels 54 is reduced.

  The present invention is not limited to the above-described embodiments, and an appropriate combination of the elements of each embodiment is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to each embodiment based on the knowledge of those skilled in the art, and embodiments to which such modifications are added can also be included in the scope of the present invention. Here are some examples.

  In S11 of FIG. 3 or S31 of FIG. 4, instead of determining whether or not the ignition key is turned off, it is determined whether or not the lock pin of the differential lock mechanism 60 has advanced into the lock holder. Good. In this case, the differential lock mechanism 60 is provided with a lock sensor that detects advancement / retraction of the lock pin with respect to the lock holder. Thereby, it is possible to directly detect whether or not the steering shaft 14 is locked by the steering lock mechanism 20.

  In S11 of FIG. 3 or S31 of FIG. 4, instead of determining whether or not the ignition key is turned off, it may be determined whether or not the key is in the key cylinder. In this case, the steering device 80 is provided with a key presence / absence detection sensor that detects whether or not a key is inserted into the key cylinder. This also makes it possible to determine whether or not the vehicle is parked.

  The steering lock mechanism 20 does not lock the rotation of the steering shaft 14 mechanically in conjunction with the rotation of the key cylinder, but may lock the rotation of the steering shaft 14 electrically. In this case, an electric actuator such as a motor or a solenoid is connected to the lock bar. When it is determined that the ignition key is turned off using the detection result of the ignition sensor 18, the electric actuator is operated to lock the rotation of the steering shaft 14, and it is determined that the ignition key is turned on. The electric actuator is operated in reverse to unlock the rotation of the steering shaft 14. In this way, in the steering device 80 provided with the steering lock mechanism 20 that electrically locks the rotation of the steering shaft 14, the force acting in the turning direction of the front wheels 54 is transmitted to the steering lock mechanism 20. The necessity for increasing the size of the steering lock mechanism 20 is reduced, and the cost can be suppressed.

  The differential lock mechanism can lock and unlock the differential between the steering shaft 14 and the output shaft 15 by engaging or releasing the flex spline and the stator gear or the driven gear. Good. For example, the differential lock mechanism may release the meshing between the flexspline and the driven gear or the stator gear by moving the flexspline together with the wave generating mechanism to the stator gear side or the driven gear side. Further, the differential lock mechanism 60 may lock the differential between the steering shaft 14 and the output shaft 15 by moving the flex spline to a position where it engages with both the stator gear and the driven gear. Accordingly, when torque is applied to the transmission ratio variable unit 22, a differential in the rotational direction can be generated between the steering shaft 14 and the output shaft 15, and the steering lock mechanism 20 or the torque sensor 24 can be controlled. The applied torque can be reduced.

1 is an overall configuration diagram of a steering system according to a first embodiment. It is a functional block diagram of transmission ratio variable unit ECU concerning a 1st embodiment. It is a flowchart which shows the operation | movement procedure of the steering apparatus contained in the steering system which concerns on 1st Embodiment. It is a flowchart which shows the operation | movement procedure of the steering apparatus which concerns on 2nd Embodiment. It is a whole block diagram of the steering system which concerns on 3rd Embodiment. It is a whole block diagram of the steering system which concerns on 4th Embodiment. It is a whole block diagram of the steering system which concerns on 5th Embodiment. It is a whole block diagram of the steering system which concerns on 6th Embodiment.

Explanation of symbols

  10A to F Steering system, 12 Steering wheel, 14 Steering shaft, 15 Output shaft, 16 Steering angle sensor, 18 Ignition sensor, 20 Steering lock mechanism, 22 Transmission ratio variable unit, 24 Torque sensor, 32 Electric power steering mechanism, 80A to F steering device, 100 transmission ratio variable unit ECU, 150 EPSECU.

Claims (4)

A steering lock mechanism for locking the rotation of the steering shaft coupled to the steering wheel;
A transmission ratio variable unit that generates a differential in the rotational direction between the steering shaft and an output shaft coupled to the steering unit that steers the wheel;
The transmission ratio variable unit has a rotational direction differential between the steering shaft and the output shaft so that torque applied to the steering shaft or the output shaft is reduced when the steering shaft is locked by the steering lock mechanism. A steering device characterized by being generated.   The variable transmission ratio unit rotates between the steering shaft and the output shaft by operating an actuator so that a torque applied to the steering shaft or the output shaft is reduced when the steering shaft is locked by the steering lock mechanism. The steering apparatus according to claim 1, wherein a direction differential is generated.   The transmission ratio variable unit is disposed between the steering shaft and the output shaft by releasing the differential regulation in the rotational direction between the steering shaft and the output shaft in a state where the steering shaft is locked by the steering lock mechanism. The steering apparatus according to claim 1, wherein a differential in the rotational direction is generated.   The transmission ratio variable unit reduces the torque applied to the steering shaft or the output shaft when a torque larger than a predetermined torque is applied to the steering shaft or the output shaft while the steering shaft is locked by the steering lock mechanism. The steering apparatus according to any one of claims 1 to 3, wherein a differential in the rotational direction is generated between the steering shaft and the output shaft.

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