JP2007203799A - Transmission ratio variable device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission ratio variable device capable of performing more stable steering operation. <P>SOLUTION: A microcomputer 61 is equipped with a catching detection part 72 as a detection means for detecting the catching of the foreign matter in a wave-motion gear mechanism. A catching detection signal Ss output by the catching detection part 72 is input into a lock control part 71. When the catching detection signal Ss indicates the catching of the foreign matter, the lock control part 71 does not perform the control to make a locking device 42 a locking state even when the establishing condition of the lock determination is satisfied. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transmission ratio variable device.

  Conventionally, by using a wave gear mechanism as a differential mechanism, there is a transmission ratio variable device that transmits rotation to the output shaft by adding rotation based on the motor drive to the rotation of the input shaft based on the steering operation. The variable ratio device is provided with a lock device that locks the motor shaft connected to the wave generator and the housing so that they cannot rotate relative to each other. And at the time of fail safe or IG off, the rotation of the motor shaft is restricted by the operation of the locking device to prevent the torque transmission between the input shaft and the output shaft from being disabled. (See Patent Document 1).

  By the way, in the transmission ratio variable device using such a wave gear mechanism, the housing integrated rotation type in which the housing rotates integrally with the input shaft as shown in Patent Document 1, and the housing is fixed to a non-rotating part of the vehicle. There is a fixed housing type (for example, see Patent Document 2). However, the locking device has basically the same configuration in both types. For this reason, the lock state of the input / output shaft in these two types is different from each other.

That is, in the housing-integrated rotation type, the motor shaft rotates integrally with the input / output shaft by the operation of the lock device, and the wave generator is thereby stopped. On the other hand, in the fixed housing type, the input / output shaft rotates with the steering operation, but the motor shaft locked to the housing does not rotate, so that the wave generator is apparently activated (the flex spline pressing portion). Is in a rotating state). In other words, even during the lock operation, the input / output shafts connected to the circular splines and flexsplines (or both flexsplines in the case of a flat type having a pair of coaxially arranged flexsplines) By rotating relative to the motor shaft connected to each other, the relative rotation with respect to each other is slightly possible based on the difference in the number of teeth of each connected spline.
JP 2004-9982 A JP 2004-175336 A

  However, if the relative rotation between the flex spline and the circular spline is restricted due to the characteristics of the wave gear mechanism, the rotating shaft connected to the wave generator also cannot rotate. For this reason, in the housing-integrated rotation type, when a foreign object is caught in the wave gear mechanism, the input / output shaft cannot rotate relative to the motor shaft connected to the wave generator. If the lock operation is executed, the steering operation may be hindered.

  Normally, the lock device is provided with a torque limiter (torque limit ring), and when the steering torque is input above a certain level, the lock is automatically released. . However, the threshold value is set to a somewhat large value (for example, about 5 Nm) so as not to hinder the original function of the locking device, and cannot be a means for solving such a problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a transmission ratio variable device that enables a more stable steering operation.

  In order to solve the above-described problems, the invention according to claim 1 is characterized in that a differential mechanism that adds rotation based on motor drive to rotation of an input shaft based on a steering operation and transmits the rotation to an output shaft, and the differential mechanism And a housing that houses a motor as a drive source and is fixed to a non-rotating part, a lock device that locks the housing and the motor shaft so as not to rotate relative to each other, and a control unit that controls the operation of the motor and the lock device The differential mechanism includes a circular spline, a flex spline coaxially disposed so as to partially mesh with the circular spline inside the circular spline, and the flex spline by being driven by a motor. A transmission ratio variable device using a wave gear mechanism comprising a wave generator for rotating a meshing portion, A detection means for detecting the entrapment of foreign object into the moving gear mechanisms, wherein, when detecting the entrapment, to the control so as not to perform the locking, and the gist.

  According to the above configuration, when the foreign object is caught in the wave gear mechanism and the input / output shaft cannot rotate relative to the motor shaft connected to the wave generator, the lock device is set to the locked state. Control is not performed. Accordingly, it is possible to prevent the input / output shaft from rotating relative to the motor shaft locked to the housing fixed to the non-rotating portion, thereby preventing the steering operation from being hindered. be able to.

  According to a second aspect of the present invention, the detection means causes the pinching to occur when a rotational angular velocity difference between either the input shaft or the output shaft and the motor shaft is a predetermined threshold value or less. The gist is to determine.

  That is, in the fixed housing type transmission ratio variable device, the input / output shaft rotates relative to the motor shaft when the input / output shaft rotates in accordance with the steering operation even during the lock operation. Therefore, when the rotational angular velocity difference between the input shaft or the output shaft and the rotational angular velocity of the motor shaft is substantially zero, the input / output shaft and the motor shaft rotate together as a result of the foreign object being caught in the wave gear mechanism. It can be determined that Therefore, according to the above-described configuration, it is possible to accurately detect foreign object pinching with a simple configuration. In many cases, in the vehicle steering device, the steering angular velocity can be applied as the rotational angular velocity of the input shaft.

  According to a third aspect of the present invention, the control means controls the operation of the motor by feedback control based on a deviation between an actual value of the motor shaft and a command value, and the detection means When the device is in an unlocked state, the gist is to detect pinching based on the rotational angular velocity difference when the deviation is equal to or greater than a predetermined threshold.

  That is, at the time of non-locking (during normal control), the rotational angular velocity difference between the input / output shaft and the motor shaft may be substantially zero due to motor control. However, if the deviation between the command value that is the basis of the motor control and the actual value shows a value that cannot normally be taken, the motor shaft cannot rotate due to the occurrence of foreign object pinching, and the actual value follows the command value. It can be estimated that it is not possible. Therefore, according to the above configuration, it is possible to detect the inclusion of a foreign object with higher accuracy by excluding the control exception as described above.

The gist of the invention described in claim 4 is that the control means restricts the control amount of the motor to be gradually increased after the pinching state is released.
That is, the transmission ratio variable device is forcibly locked by the occurrence of the pinching. For this reason, if normal motor control is resumed as soon as the jamming is eliminated, there is a possibility of sudden operation, which may impair the steering feeling. However, according to the above configuration, the control amount of the motor gradually increases after the pinching is eliminated, so that a steering feeling due to a sudden operation is not caused.

The gist of the invention described in claim 5 is that it is provided with warning means for warning that the pinching is detected.
According to the above configuration, even when the operation of the transmission ratio variable device is stopped due to the occurrence of pinching, it is possible to relieve the sense of anxiety by informing the passenger of the occurrence factor in advance.

  ADVANTAGE OF THE INVENTION According to this invention, the transmission ratio variable apparatus which enables more stable steering operation can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a steering apparatus 1 according to the present embodiment. As shown in the figure, a steering shaft 3 to which a steering wheel (steering) 2 is fixed is connected to a rack 5 via a rack and pinion mechanism 4. It is converted into a reciprocating linear motion of the rack 5 by the and pinion mechanism 4. The traveling direction of the vehicle is changed by changing the rudder angle of the steered wheels 6, that is, the tire angle, by the reciprocating motion of the rack 5.

  Further, the steering device 1 of the present embodiment has a transmission ratio variable device 7 that varies the ratio of the steering angle (tire angle) of the steered wheels 6 to the steering angle (steering angle) of the steering wheel 2, that is, the transmission ratio (gear ratio). And IFSECU 8 as control means for controlling the operation of the transmission ratio variable device 7.

  As shown in FIG. 2, in the steering device 1 of the present embodiment, the transmission ratio variable device 7, the electric power steering device 9, and the torque sensor 10 are integrated as a drive unit 11 and provided at one end of the steering column 12. Yes.

  More specifically, the drive unit 11 has a housing 13 formed in a substantially cylindrical shape, and the housing 13 is fixed to a non-rotating part of the vehicle. The transmission ratio variable device 7, the wheel 14 constituting the electric power steering device 9, and the torque sensor 10 are accommodated in the housing 13. A drive motor (not shown) of the electric power steering device 9 is installed outside the housing 13. And it is drive-coupled with the wheel 14 via the pinion.

  The transmission ratio variable device 7 includes an input shaft 15, an output shaft 16, a differential mechanism 17 provided between the input shaft 15 and the output shaft 16, and a motor 18 that drives the differential mechanism 17. The input shaft 15 and the output shaft 16 are coaxially arranged along the axial direction of the housing 13. The input shaft 15 and the output shaft 16 are rotatably supported by the bearings 20a and 20b and the bearing 21 with one end thereof exposed to the outside of the housing 13, and the outer end portions 15a and 16a thereof are respectively It is connected to the column shaft 22 and an intermediate shaft (not shown).

  In addition, a brushless motor having a hollow motor shaft 24 is employed as the motor 18, and the differential mechanism 17 is disposed on the side opposite to the steering side (left side in the figure) of the motor 18. The input shaft 15 is inserted into the motor shaft 24 so that the inner side end 15 b is connected to the differential mechanism 17. In the present embodiment, the inner side end portion 16 b of the output shaft 16 is formed in a hollow shape, and the differential mechanism 17 is disposed in the hollow portion 25. The wheel 14 is formed integrally with the output shaft 16 on the outer periphery thereof.

  More specifically, the differential mechanism 17 employs a wave gear mechanism 27. The wave gear mechanism 27 includes a pair of circular splines 31 and 32 arranged coaxially, a cylindrical flexspline 33 arranged coaxially so as to mesh with the splines, and a wave generator arranged inside the flexspline 33. The end of the motor shaft 24 on the side opposite to the steering side is connected to the wave generator 34. The inner end 15b of the input shaft 15 inserted into the motor shaft 24 is connected to a circular spline 31 on the counter-steer side via a connecting member 35, and the other (steer side) circular spline 32 is connected to the same. It connects with the inner wall of the hollow part 25 in which the circular spline 32 is arrange | positioned.

  That is, the rotation of the input shaft 15 accompanying the steering operation is transmitted from the circular spline 31 connected to the input shaft 15 to the circular spline 32 via the flex spline 33, and thereby transmitted to the output shaft 16. The circular splines 31 and 32 have different numbers of teeth, and the flexsplines 33 are arranged inside the circular splines 31 and 32 in a state of being bent in a substantially elliptical shape. The outer teeth are partially meshed with the inner teeth of the circular splines 31 and 32, respectively. Then, the wave generator 34 disposed inside the flexspline 33 is driven by the motor 18, and the elliptical shape of the bent flexspline 33, that is, the meshing part of the circular splines 31 and 32 rotates. The rotation based on the motor drive is added to the rotation based on the steering operation, whereby the rotation transmission ratio between the input shaft 15 and the output shaft 16, that is, the transmission ratio (gear ratio) between the steering wheel and the steering wheel. Is made variable.

  In the present embodiment, the input shaft 15 includes a first shaft 37 connected to the column shaft 22, a second shaft 38 inserted into the motor shaft 24 and connected to the circular spline 31, and the first shaft 37. And a torsion bar 39 for connecting the second shaft 38. The torque sensor 10 detects the torsion angle of the torsion bar 39 as a magnetic flux change by the magnet 40 and the magnetic sensor (Hall IC) 41 provided on the first shaft 37 and the second shaft 38 at positions facing each other. Thus, the steering torque is detected.

  Further, the transmission ratio variable device 7 includes a lock device 42 that prevents the input shaft 15 and the output shaft 16 from freely rotating by locking the motor shaft 24 so as not to rotate relative to the housing 13. More specifically, as shown in FIGS. 2 and 3, the locking device 42 is fixed to the motor shaft 24, thereby rotating integrally with the motor shaft 24, and a support shaft 44 provided on the housing 13 side. Thus, a lock arm 45 pivotally supported outside the lock holder 43 and a solenoid 46 for driving the lock arm 45 are configured. The lock holder 43 is formed in a substantially annular shape, and a plurality of engaging grooves 47 extending in the thickness direction (axial direction) are recessed in the outer periphery thereof. In this embodiment, the lock holder 43 is fixed to the motor shaft 24 via a torque limit ring 48 serving as a torque limiter. When there is an input torque greater than a predetermined value, the lock holder 43 and the motor It is configured to allow relative rotation with the shaft 24. On the other hand, one end of the lock arm 45 is provided with an engaging claw 49 projecting toward the outer peripheral surface of the lock holder 43, and the other end is connected to a plunger 46a of the solenoid 46. The lock arm 45 is urged by the elastic force of the coil spring 50 so that the end of the engagement claw 49 side rotates toward the lock holder 43 side.

  In other words, the lock arm 45 is driven by the solenoid 46 so that the engaging claw 49 is disposed on the radially outer side of the lock holder 43 against the elastic force of the coil spring 50 at the normal time (when not locked). ing. At the time of locking, by stopping energization of the solenoid 46, the end of the lock arm 45 on the side of the engagement claw 49 rotates toward the lock holder 43, and the engagement claw 49 is moved to the lock holder 43 side. By engaging with the engaging groove 47, the motor shaft 24 and the housing 13 are locked so as not to rotate relative to each other.

Next, the electrical configuration of the steering device of this embodiment and the control mode of the transmission ratio variable device will be described.
As shown in FIG. 1, the steering angle θs (steering angular velocity ωs) detected by the steering angle sensor 51 and the vehicle speed V detected by the vehicle speed sensor 52 are input to the IFSECU 8. The IFSECU 8 controls the rotation of the transmission ratio variable device 7 by controlling the rotation of the motor 18 that is a drive source of the transmission ratio variable device 7 based on the steering angle θs (steering angular velocity ωs) and the vehicle speed V, that is, transmission. Execute variable ratio control. In the present embodiment, the IFSECU 8 is connected to the EPSECU 54 that controls the operation of the electric power steering device 9 via the in-vehicle network 53. By sharing a plurality of vehicle state quantities and control signals through mutual communication between IFSECU 8 and EPSECU 54, integrated control of power assist control and transmission ratio variable control is possible.

  FIG. 4 is a control block diagram of the transmission ratio variable device in the present embodiment. As shown in the figure, the IFSECU 8 includes a microcomputer 61 that outputs a motor control signal and a drive circuit 62 that supplies drive power to the motor 18 based on the motor control signal. Each control block shown below is realized by a computer program executed by the microcomputer 61.

  The microcomputer 61 includes a gear ratio variable control calculation unit 63 and a differential steer control calculation unit 64, and the steering angle θs and the vehicle speed V are input to the gear ratio variable control calculation unit 63. Is inputted with the vehicle speed V and the steering angular velocity ωs. The gear ratio variable control calculation unit 63 calculates a gear ratio variable command angle θgr *, which is a control target component for changing the gear ratio (transmission ratio) according to the vehicle speed V, and the differential steer control calculation unit 64 Then, the differential steering command angle θls *, which is a control target component for improving the responsiveness of the vehicle, is calculated according to the steering angular velocity.

  The gear ratio variable command angle θgr * and the differential steer command angle θls * calculated by the gear ratio variable control calculation unit 63 and the differential steer control calculation unit 64 are input to the adder 65. The adder 65 calculates the rotation command angle θm * of the motor 18 by superimposing the gear ratio variable command angle θgr * and the differential steer command angle θls *.

  The rotation command angle θm * calculated by the adder 65 is input to the subtractor 67 together with the motor rotation angle (actual rotation angle) θm output from the rotation angle sensor 66 provided in the motor 18 to be a position control calculation unit. 68 calculates a current command ε by feedback calculation based on a deviation Δθm between the rotation command angle θm * and the motor rotation angle θm, and inputs the current command ε to the motor control signal output unit 69. The motor control signal output unit 69 generates a motor control signal based on the current command ε, and the drive circuit 62 supplies the drive power based on the motor control signal to the motor 18 of the transmission ratio variable device 7. The operation of the transmission ratio variable device 7 is controlled.

  In addition to the drive circuit 62 for variable transmission ratio control, the IFSECU 8 includes a drive circuit 70 for lock control, that is, for supplying drive power to the solenoid 46. The microcomputer 61 sends a lock control signal to the drive circuit 70. A lock control unit 71 for outputting Sr is provided. In the present embodiment, the IG OFF signal Sig and the abnormality occurrence signal Str of the electric power steering device 9 are input to the IFSECU 8. Then, the lock control unit 71 determines whether or not the lock device 42 should be locked and whether or not the lock state should be released based on these input control signals (lock determination). By outputting a corresponding lock control signal Sr, the operation of the lock device 42 is controlled through on / off of power supply from the drive circuit 70.

  Further, in the present embodiment, the microcomputer 61 includes a pinching detection unit 72 as detection means for detecting the pinching of foreign matter in the wave gear mechanism 27, and the lock control unit 71 includes an output of the pinching detection unit 72. The pinching detection signal Ss to be input is input. Then, when the pinching detection signal Ss indicates the pinching of a foreign object, the lock control unit 71 does not perform control to lock the lock device 42 even when the lock determination is satisfied. (Lock open control).

  More specifically, the amount of change per unit time (sampling period) of the steering angle θs and the motor rotation angle θm, that is, the steering angular velocity ωs and the motor rotation angular velocity ωm are input to the pinching detection unit 72. Then, the pinching detection unit 72 determines that foreign object pinching has occurred in the wave gear mechanism 27 when the difference between these rotational angular velocities is less than a predetermined threshold.

  That is, as described above, in the case of a fixed housing type such as the transmission ratio variable device 7 of the present embodiment, when the input shaft 15 rotates with the steering operation, the input shaft 15 is Rotate relative to the motor shaft 24. Therefore, when the rotational angular velocity difference between the steering angular velocity ωs indicating the rotational angular velocity of the input shaft 15 and the motor rotational angular velocity ωm is substantially zero, the input shaft 15 and the motor shaft 24 are Can be determined to be in a state of integrally rotating.

  In addition, in the present embodiment, the pinching detection unit 72 includes a deviation between the steering angular velocity ωs and the motor rotation angular velocity ωm, the lock control signal Sr, and the rotation command angle θm * used for motor control and the motor rotation angle θm. Δθm is input. When the lock is not performed, the pinching determination based on the rotational angular velocity difference is executed when the deviation Δθm between the command value and the actual value is equal to or greater than a predetermined threshold value.

  That is, at the time of non-locking (during normal control), there is a possibility that the rotational angular velocity difference between the steering angular velocity ωs and the motor rotational angular velocity ωm is substantially zero due to motor control. However, if the deviation Δθm between the rotation command angle θm * and the motor rotation angle θm, which is the basis of the motor control, shows a value that cannot normally be obtained, the motor shaft 24 cannot rotate due to the occurrence of foreign object pinching, and the motor It can be estimated that the rotation angle θm cannot follow the rotation command angle θm *.

  Here, in this embodiment, the pinching detection signal Ss output from the pinching detection unit 72 is also input to the motor control signal output unit 69, and the motor control signal output unit 69 receives the pinching detection signal. When Ss indicates the occurrence of pinching, the output of the motor control signal to the drive circuit 62 is stopped. When the pinching detection signal Ss indicates the cancellation of the pinching state, the output of the motor control signal is limited so that the control amount of the motor 18 gradually increases (gradual increase). In this embodiment, the control amount of the motor 18 is limited using a primary filter having a predetermined time constant.

  That is, the transmission ratio variable device 7 is forcibly locked due to the occurrence of pinching. Therefore, during this time, there is a possibility that the deviation Δθm between the rotation command angle θm * and the motor rotation angle θm becomes a large value.If normal motor control is resumed immediately after the jamming is eliminated, the deviation Δθm It may operate suddenly and damage the steering feeling. Therefore, after the jamming is resolved, the motor control signal to be output is limited to gradually increase the control amount of the motor 18, so that the operation of the transmission ratio variable device 7 can be smoothly resumed and good steering feeling can be achieved. Secure it.

Next, a description will be given of processing procedures for the foreign object pinching determination and lock open control.
As shown in the flowchart of FIG. 5, when the microcomputer 61 reads the steering angle θs (steering angular velocity ωs) and the motor rotational angle θm (motor rotational angular velocity ωm) as sensor values (step 101), first, the wave gear mechanism 27 is already present. It is determined whether or not foreign matter is caught in (step 102), and if not (step 102: NO), it is subsequently determined whether or not the lock device 42 is locked (step 103). ). Next, when it is determined in step 103 that the lock state is established (step 103: YES), the microcomputer 61 has a rotational angular velocity difference (absolute value) between the steering angular velocity ωs and the motor rotational angular velocity ωm equal to or less than a predetermined threshold α1. (Step 104). If the rotational angular velocity difference is equal to or less than the threshold value α1 (| ωm−ωs | ≦ α1, step 104: YES), it is determined that the foreign object has been caught (step 105). . Then, even when the conditions for establishing the lock determination are satisfied, the lock open control that does not perform the control to lock the lock device 42 is turned on (step 106), and warning means provided on the meter panel (not shown) The warning lamp 73 (see FIG. 4) is turned on (step 107).

  On the other hand, when it is determined in step 103 that the vehicle is in the unlocked state (step 103: NO), the microcomputer 61 acquires a deviation Δθm between the rotation command angle θm * used for motor control and the motor rotation angle θm (step 103). 108) Subsequently, it is determined whether or not the deviation Δθm is equal to or larger than a predetermined threshold value β (step 109). If the deviation Δθm is greater than or equal to the threshold value β (| Δθm | ≧ β, Step 109: YES), the pinching determination at Step 105 is executed.

  If the rotational angular velocity difference is larger than the threshold value α1 in step 104 (| ωm−ωs |> α1, step 104: NO), or if the deviation Δθm is smaller than the threshold value β in step 109 (| Δθm | <β In Step 109: NO), the microcomputer 61 does not execute the processing of Step 105 to Step 107 on the assumption that no foreign matter is caught.

  If it is determined in step 102 that foreign matter is already caught in the wave gear mechanism 27 (step 102: YES), the microcomputer 61 subsequently rotates the steering angular velocity ωs and the motor rotational angular velocity ωm. It is determined whether the angular velocity difference (absolute value) is equal to or smaller than a predetermined threshold value α2 (step 110). If the rotational angular velocity difference is larger than the threshold value α2 (| ωm−ωs |> α2, step 110: NO), it is determined that the foreign object has been caught (step 111), and the lock open control is performed. The warning lamp 73 is turned off (step 112), the warning lamp 73 is turned off (step 113), and the control of the motor 18 is resumed while limiting the control amount to be gradually increased (step 114).

  If it is determined in step 110 that the rotational angular velocity difference is equal to or less than the threshold value α2 (| ωm−ωs | ≦ α2, step 110: YES), the microcomputer 61 has not eliminated foreign object pinching. As a result, the processing of step 111 to step 114 is not executed.

As described above, according to the present embodiment, the following operations and effects can be obtained.
(1) The microcomputer 61 includes a pinch detection unit 72 as detection means for detecting the pinch of foreign matter in the wave gear mechanism 27, and the lock control unit 71 receives a pinch detection signal Ss output from the pinch detection unit 72. Entered. Then, when the pinching detection signal Ss indicates the pinching of a foreign object, the lock control unit 71 does not perform control to lock the lock device 42 even when the lock determination is satisfied. (Lock open control).

  According to the above configuration, when the foreign object is caught in the wave gear mechanism 27 and the input shaft 15 cannot rotate relative to the motor shaft 24 connected to the wave generator 34, the lock device 42 is provided. Control to lock is not performed. Accordingly, it is possible to prevent the input shaft 15 from rotating relative to the motor shaft 24 locked to the housing 13 fixed to the non-rotating portion, thereby preventing the steering operation. Can be prevented.

(2) The microcomputer 61 turns on a warning lamp 73 as a warning means provided on the meter panel when a foreign object is caught.
According to the above configuration, even when the operation of the transmission ratio variable device 7 is stopped due to the occurrence of the pinching, the anxiety can be eased by notifying the passenger of the occurrence factor in advance.

In addition, you may change this embodiment as follows.
In the present embodiment, the microcomputer 61 includes a pinching detection unit 72 that detects the pinching of a foreign object in the wave gear mechanism 27, and the pinching detection unit 72 has a difference in rotational angular velocity between the steering angular velocity ωs and the motor rotational angular velocity ωm. Is less than the predetermined threshold value, it is determined that foreign matter is caught in the wave gear mechanism 27. However, the mode of the detection means for detecting the foreign object is not limited to this. For example, the wave gear mechanism 27 itself may be provided with a device for detecting the foreign object. Good.

  In the present embodiment, the steering angular velocity ωs is used as an indication of the rotational angular velocity of the input shaft 15. However, the rotational angular velocity of the input shaft 15 or the output shaft 16 may be detected more directly and used. .

  In the present embodiment, the wave gear mechanism 27 is a so-called flat type (ring type) having a pair of circular splines 31 and 32 arranged coaxially, but is not limited thereto. A so-called cup type in which a cup-shaped flexspline is meshed with the circular spline may be used.

  In the present embodiment, the warning lamp 73 is turned on as the warning means. However, the warning means may use other notification forms such as a warning sound.

The schematic block diagram of a steering device. The schematic block diagram of a transmission ratio variable apparatus. The schematic block diagram of a locking device. The control block diagram of a transmission ratio variable apparatus. The flowchart which shows the process sequence of foreign object pinching determination and lock open control.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steering device, 7 ... Transmission ratio variable device, 8 ... IFSECU, 13 ... Housing, 15 ... Input shaft, 16 ... Output shaft, 17 ... Differential mechanism, 18 ... Motor, 24 ... Motor shaft, 27 ... Wave gear mechanism , 31, 32 ... circular spline, 33 ... flex spline, 34 ... wave generator, 42 ... lock device, 61 ... microcomputer, 62,70 ... drive circuit, 68 ... position control calculation unit, 71 ... lock control unit, 72 ... Pinch detector 73, warning lamp, θs, steering angle, ωs, steering angular velocity, θm, motor rotational angle, ωm, motor rotational angular velocity, θm *, rotational command angle, Δθm, deviation, α1, α2, β, threshold, Sr: lock control signal, Ss: pinching detection signal.

Claims (5)

A differential mechanism that adds rotation based on motor driving to rotation of an input shaft based on steering operation and transmits the rotation to an output shaft, and a housing that houses the differential mechanism and a motor that is a driving source and is fixed to a non-rotating portion A lock device that locks the housing and the motor shaft so as not to rotate relative to each other, and a control unit that controls the operation of the motor and the lock device. The differential mechanism includes a circular spline, and the circular spline. A wave gear mechanism comprising a flex spline coaxially arranged so as to partially mesh with the circular spline and a wave generator that rotates the meshing portion of the flex spline when driven by a motor was used. A transmission ratio variable device,
A detecting means for detecting a foreign object sandwiched in the wave gear mechanism;
The transmission ratio variable device according to claim 1, wherein the control means performs the control so as not to perform the lock when the pinching is detected. The transmission ratio variable device according to claim 1,
The detecting means determines that the pinching has occurred when a rotational angular velocity difference between either the input shaft or the output shaft and the motor shaft is equal to or less than a predetermined threshold;
A transmission ratio variable device characterized by the above. The transmission ratio variable device according to claim 2,
The control means controls the operation of the motor by feedback control based on a deviation between an actual value of the motor shaft and a command value,
The detecting means detects pinching based on the rotational angular velocity difference when the deviation is equal to or greater than a predetermined threshold when the locking device is in an unlocked state;
A transmission ratio variable device characterized by the above. In the transmission ratio variable device according to any one of claims 1 to 3,
The variable transmission ratio device according to claim 1, wherein the control means limits the control amount of the motor to be gradually increased after the pinching state is released. In the transmission ratio variable device according to any one of claims 1 to 4,
Comprising warning means for warning that the pinching is detected,
A transmission ratio variable device characterized by the above.

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