Shift range control apparatus

A shift range control apparatus switching a shift range by controlling a drive of a motor, the shift range control apparatus includes: an idle running determiner that is configured to determine whether a rotation state of the motor is an idle running state in which the motor rotates within a range of play existing between a motor shaft being a rotation shaft of the motor and an output shaft to which a rotation of the motor is transmitted; and a current limiter that is configured to limit a current of the motor when it is determined that the rotation state of the motor is the idle running state.

CROSS-REFERENCE TO RELATED APPLICATION

This application is the U.S. national phase of International Application No. PCT/JP2017/008699 filed Mar. 6, 2017, which designated the U.S. and claims priority to Japanese Patent Application No. 2016-87741 filed on Apr. 26, 2016, the entire contents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a shift range control apparatus.

BACKGROUND ART

A shift range switching apparatus that switches a shift range by controlling a motor in accordance with a shift range switching request from a driver has been known. Patent Literature 1 employs a switched reluctance motor as a driving source of the shift range switching mechanism, and rotates a detent lever integrated with the output shaft through a reducer, for example.

The inventor of the present disclosure finds out the following. A play such as gear backlash exists between a motor shaft and an output shaft. Therefore, the motor shaft quickly rotates in a zone of the play, and a collision sound may happen when a zone of the play ends.

PRIOR ART LITERATURE

Patent Literature

SUMMARY OF INVENTION

It is an object of the present disclosure to provide a shift range control apparatus enabling to suppress occurrence of a collision sound at the time of switching a shift range.

A shift range control apparatus according to one aspect of the present disclosure switches a shift range by controlling drive of a motor and includes an idle running determiner and a current limiter.

The idle running determiner determines whether a rotation state is an idle running state that the motor rotates within a range of play existing between a motor shaft that is a rotation shaft of the motor and an output shaft to which a rotation of the motor is transmitted.

When it is determined as the idle running state, the current limiter limits a current of the motor.

It may be possible to suppress occurrence of the collision sound at the time of shift range switching.

DESCRIPTION OF EMBODIMENTS

The shift range control apparatus according to the present disclosure will be explained with reference to the drawings. Hereinafter, in multiple embodiments, an explanation will be omitted by applying an identical reference to actually similar configuration.

First Embodiment

FIGS. 1 to 7show the shift range control apparatus according to a first embodiment of the present disclosure.

As shown inFIG. 1andFIG. 2, a shift-by-wire system1includes a motor10, a shift range switching mechanism20, a parking lock mechanism30, a shift range control apparatus40, or the like.

The motor10is rotated by power supplied from a battery45(as described inFIG. 3) installed in a vehicle (not shown) and functions as a drive source of the shift range switching mechanism20. The motor10is employed, the motor being capable of changing the amount of a current by feedback control and varying the command for each phase. The motor10according to the embodiment is a permanent magnet DC brushless motor. As shown inFIG. 3, the motor10includes two winding groups11and12. The first winding group11includes a U1coil111, a V1coil112, and a W1coil113. The second winding group12includes a U2coil121, a V2coil122, and a W2coil123.

As shown inFIG. 2, an encoder13detects a rotation position of a rotor (not shown) of the motor10. The encoder13is configured from a magnet rotating with the rotor, a hall IC detecting magnetic field, or the like. The encoder13synchronizes with the rotation of the rotor, and outputs A-phase and B-phase pulse signals for each predetermined angle.

A reducer14is placed between an output shaft15and the motor shaft of the motor10. The reducer14reduces the rotation of the motor10, and outputs the rotation of the motor to the output shaft15. Thereby, the rotation of the motor10is transmitted to the shift range switching mechanism20. An output shaft sensor16detects an output shaft angle θs being an angle of the output shaft. The output shaft sensor16is placed in the output shaft15for detecting the angle of the output shaft15. The output shaft sensor16is a potentiometer, for example.

As shown inFIG. 1, the shift range switching mechanism20includes a detent plate21, a detent spring25, or the like. The shift range switching mechanism20transmits to a manual valve28and the parking lock mechanism30, a rotation drive force output from the reducer14.

The detent plate21is fixed to the output shaft15and driven by the motor10. According to the embodiment, a direction in which the detent plate21moves away from a proximal end of the detent spring25is referred to as a forward rotation direction, and the direction in which the detent plate approaches the proximal end is referred to as a reverse rotation direction.

The detent plate21has a pin24protruding parallel with the output shaft15. The pin24is connected to the manual valve28. As the detent plate21is driven by the motor10, the manual valve28reciprocates along an axial direction. That is, the shift range switching mechanism20converts the rotation motion of the motor10to linear movement and transmits it to the manual valve28. The manual valve28is placed at a valve body29. The manual valve28reciprocates along the axial direction, and thereby a hydraulic pressure supply path to a hydraulic clutch (not shown) is switched. An engaged state of the hydraulic clutch is switched, so that the shift range is switched.

Four recesses22are placed on the side closer to the detent spring25of the detent plate21, the four recesses retaining the manual valve28at positions corresponding to each shift range. The recesses22each correspond to each of the shift ranges of D (drive), N (neutral), R (reverse), and P (park) ranges from the proximal end of the detent spring25.

The detent spring25is a resiliently deformable plate-shaped member and a detent roller26is placed at a tip of the detent spring25. The detent roller26fits into one of the recesses22.

The parking lock mechanism30includes a parking rod31, a conical member32, a parking lock pawl33, a shaft part34, and a parking gear35.

The parking rod31is provided as a substantially L-shape, and a side of one end311is fixed to the detent plate21. The conical member32is provided to the other end312of the parking rod31. The conical member32is formed so as to contract toward the other end312. When the detent plate21pivots in the reverse rotation direction, the conical member32moves toward the direction of arrow P.

The parking lock pawl33abuts on a conical surface of the conical member32and can pivot around the shaft part34. On the side of the parking gear35in the parking lock pawl33, the parking lock pawl33has a protrusion331that can mesh with the parking gear35. When the detent plate21rotates in the reverse rotation direction, the conical member32moves in the direction of arrow P, and the parking lock pawl33is pushed up so that the protrusion331meshes with the parking gear35. By contrast, when the detent plate21rotates in the forward rotation direction and the conical member32moves in the direction of arrow Not P, the protrusion331is dissolved to mesh with the parking gear35.

The parking gear35is placed at an axle (not shown) so as to be capable of meshing with the protrusion331on the parking lock pawl33. The parking gear35meshing with the protrusion331restricts the rotation of the axle. When the shift range is one of the ranges other than P (Not P range), the parking gear35is not locked by the parking lock pawl33, so that the rotation of the axle is not stopped by the parking lock mechanism30. When the shift range is the P range, the parking gear35is locked by the parking lock pawl33, and the rotation of the axle is restricted.

As shown inFIG. 2andFIG. 3, the shift range control apparatus40includes motor drivers41and42, an ECU50, or the like.

The motor driver41is a three-phase inverter switching the energization of first winding group11. Switching elements411to416are bridge-connected. One end of the U1coil111is connected to a connection point between the pair of U-phase switching elements411and414. One end of the V1coil112is connected to a connection point between the pair of V-phase switching elements412and415. One end of the W1coil113is connected to a connection point between the pair of W-phase switching elements413and416. The other ends of the coils111to113are connected at a connection portion115.

The motor driver42is a three-phase inverter switching the energization of second winding group12. Switching elements421to426are bridge-connected. One end of the U2coil121is connected to a connection point between the pair of U-phase switching elements421and424. One end of the V2coil122is connected to a connection point between the pair of V-phase switching elements422and425. One end of the W2coil123is connected to a connection point between the pair of W-phase switching elements423and426. The other ends of the coils121to123are connected at a connection portion125.

The switching elements411to416and421to426according to the embodiment are MOSFETs. Other devices such as IGBTs may also be employed.

A motor relay46is placed between the motor driver41and the battery45. A motor relay47is placed between the motor driver42and the battery45. The motor relays46and47turn on when a starter switch, such as an ignition switch or the like, turns on, so that power is supplied to the motor10. The motor relays46and47turn off while the starter switch turns off, so that power supply to the motor10is shut off.

The ECU50controls the drive of the motor10by controlling on-off actuation of the switching elements411to416,421to426. The ECU50controls the drive of a transmission hydraulic control solenoid6based on vehicle speed, accelerator opening degree, and driver request shift range or the like. The transmission hydraulic control solenoid6is controlled and thereby shift stage is controlled. The transmission hydraulic control solenoid6is controlled and thereby shift stage is controlled. According to the embodiment, though one ECU50controls the drive of the motor10and the solenoid6, a motor ECU for motor control controlling the motor10and an AT-ECU may be separately provided. A drive control of the motor10will be mainly explained.

As shown inFIG. 4, the ECU50includes an angle calculator51, a feedback controller52, a stationary phase energization controller61, a switching controller65and a signal generator66or the like. The ECU50is mainly configured from a microcomputer or the like. Various processes in the ECU50may be software processes of a program already stored in a tangible memory device such as a ROM and executed by a CPU, or may be hardware processes executed by special electronic circuits.

The angle calculator51calculates an actual count value Cen that is the count value of the encoder13, based on the A-phase and B-phase pulses output from the encoder13. The actual count value Cen is a value corresponding to an actual mechanical angle and an actual electrical angle of the motor10. According to the embodiment, the actual count value Cen is referred to as “an actual angle”.

As described above, the reducer14is placed between the motor shaft of the motor10and the output shaft15. When the motor shaft rotates within the range of play in gear teeth of the reducer14in a case where the starter switch turns off, the relative position between the motor shaft and the output shaft15at when the starter switch turns off may be different from the relative position between the motor shaft and the output shaft15at when the starter switch turns on. Therefore, the angle calculator51performs initial learning and calculates a correction value when the starter switch turns on. The initial learning adjusts the count value of the encoder13to the position of the output shaft15by a wall abutment control rotating the motor10in both directions and abutting to the wall in the both sides of the gear meshing with the motor shaft. The actual count value Cen may be a value after correction with the correction value.

The feedback controller52includes a phase advance filter53, a subtractor54, and a controller55, an idle running determiner57and a duty limiter58as a current limiter. The feedback controller52performs the position feedback control.

The phase advance filter53performs a phase advance compensation in which a phase of the actual count value Cen is advanced, and calculates a phase advance value Cen_pl. “The actual angle” may include the phase advance value Cen_pl executing the phase advance filter process.

The subtractor54calculates a deviation ΔCen between the phase advance value Cen_pl and the target count value Cen* corresponding to the driver request shift range inputted by operation of a shift lever (not shown) in the drawings or the like.

The controller55calculates a duty Du_a before limitation by PI control or the like so that the deviation ΔCen becomes 0 in order to match the target count value Cen* with the actual count value phase advance value Cen_pl. The position feedback control may be possible to vary magnitude of current flowing in the coils111to113,121to123and torque by changing the duty with PWM control or the like.

According to the embodiment, rectangular wave control by energization of 120° controls the drive of the motor10. In the rectangular wave control by the energization of 120°, the switching element in a side of high voltage of the first phase and a switching element in a side of low voltage of the second phase turn on. An energization phase is switched by changing combination of the first phase and the second phase every electric angle 60°. Rotation magnetic field occurs in the winding groups11,12and the motor10rotates. According to the embodiment, a rotation direction of the motor10at the time of rotating the output shaft15in the forward rotation direction is set to a forward direction. The duty at when the motor10outputs positive torque is set to positive. The duty at when the motor10outputs negative torque is set to negative. A duty range to be acquired is set to −100[%] to 100[%]. The duty is set to positive when the motor10is caused to perform the forward rotation. The duty is set to negative when the motor10is caused to perform the reverse rotation. The rotation direction of the motor10is the forward rotation direction when a brake torque (that is, negative torque) occurs for stopping the motor10performing the forward rotation. In this case, the duty becomes negative. Similarly, the duty becomes positive when the brake torque occurs for stopping the motor10performing the reverse rotation.

The idle running determiner57determines whether a rotation state of the motor10is an idle running state. The idle running determiner57turns on a current limitation flag Flg_L and outputs to the duty limiter58when the rotation state of the motor10is the idle running state.

Details of the idle running determination are described later.

The duty limiter58limits a duty to limit a maximum value of the motor current when the rotation state of the motor10is the idle running state.

The duty limiter58limits the maximum value of the duty to a maximum duty DH when the current limitation flag Flg_L turns on. In detail, the duty limiter58limits the duty Du after the limitation to the maximum duty DH, in a case where an absolute value of the duty Du_a before the limitation exceeds the maximum duty DH. The duty limiter58sets the duty Du_a to the duty Du after the limitation, in a case where the absolute value of the duty Du_a before the limitation is equal to or less than the maximum duty DH. The positive or negative of the duty after the limitation conforms to the duty before the limitation. The duty Du_a before the limitation keeps to be set as the duty Du after the limitation, in a case where the current limitation flag Flg_L turns off.

The duty Du after the limitation is output to the signal generator66.

The stationary phase energization controller61performs a stationary phase energization control. The stationary phase control energization control is a control for stopping the rotation for the motor10. The stationary phase control energization control selects the stationary phase corresponding to the electric angle and controls the switching elements411to416,421to426, so that the current flows in a predetermined direction of the selected stationary phase. An excitation phase is fixed. When the excitation phase is fixed, the motor10stops at a predetermined electric angle corresponding to the excitation phase. The stationary phase energization controller61selects the stationary phase and the energization phase based on the actual count value Cen so as to stop the motor10at the electric angle that is the closest from the present rotor position.

The stationary phase energization control is performed when difference between the actual count value Cen and the target count value Cen* becomes equal to or less than an angle determination threshold value ENth. It is regarded that the actual count value Cen substantially matches the target count value Cen* when the stationary phase energization control is performed. It may be possible to stop the motor10at a point substantially matching the target count value Cen* by stopping the electric angle that is the closest and stoppable from the present rotor position. Strictly, a gap for the motor resolution at most may occur between the electric angle corresponding to the target count value Cen* and the electric angle stopping the motor10in the stationary phase energization control. The gap of a stop position of the output shaft15is small when reduction rate of the reducer14is high, so that there is no difficulty.

The switching controller65switches a control state of the motor10. Specifically, according to the embodiment, the switching controller65switches the control state to the position feedback control or the stationary phase energization control based on the target count value Cen* and the actual count value Cen.

The switching controller65sets the control state of the motor10to the position feedback control when the driver request shift range changes. The switching controller65switches to the stationary phase energization control when an absolute value of a difference between the target count value Cen* and the actual count value Cen is equal to or less than the angle determination threshold value ENth. The switching controller65continues the stationary phase energization control until the energization duration Ta elapses after the switching to the stationary phase energization control. The switching controller65switches to the energization off control after the energization duration Ta elapses. In the energization off control, all of the switching elements411to416and421to426turn off. According to the embodiment, the absolute value of the difference between the target count value Cen* and the actual count value Cen corresponds to “a difference value between the target angle and the actual angle”.

The signal generator66generates the driving signal switching on/off of the switching elements411to416,421to426corresponding to the control state selected by the switching controller65. The signal generator66outputs to the motor drivers41and42, so that the drive of the motor10is controlled.

A relation between the motor shaft of the motor10and the output shaft15will be explained with reference toFIG. 5.FIG. 5schematically shows the relation between the motor shaft and the output shaft. InFIG. 5, the rotation directions of the motor shaft and the output shaft are explained as vertical direction of the paper surface.

As shown inFIG. 5, the reducer14is placed between the motor shaft being a rotation shaft of the motor10and the output shaft15. There is “a play” including gear backlash between the reducer14and the output shaft15. According to the embodiment, the motor10is DC brushless motor. Therefore, the motor shaft rotates within the play and the reducer14and the output shaft15may be separated by effect such as cogging torque, when the energization to the motor10is stopped. The motor10drives after the state that the reducer14and the output shaft15are separated in a side of a rotation direction and stop. The motor shaft rotates within the play in a substantial unloaded state.

The state that the motor10rotates within the play existing between the motor shaft and the output shaft15may be set as “an idle running state”. According to the embodiment, as the idle running state, a case where the motor10rotates in a state that the gear of the reducer14and the output shaft15are separated from each other in the side of rotation direction will be mainly explained.

A conversion value obtained by converting the rotation angle of the motor10corresponding to the actual count value Cen at gear ratio of the reducer14may be set as “a motor angle θm”. As described above, the actual count value Cen is a value corrected by the initial learning. Therefore, the motor angle θm and the output shaft angle θs correspond to each other when the motor shaft and the output shaft15integrally rotate. Hence, a motor angle variation amount Δθm that is a variation amount of the motor angle θm and an output shaft angle variation amount Δθs that is a variation amount of the output shaft angel θs match each other when the motor shaft and the output shaft15integrally rotate. The variation amount Δθm and Δθs are set to be respective difference values from previous calculation values.

The idle running determiner57determines the rotation state of the motor10as the idle running state when the output shaft angle variation amount Δθs and the motor angle variation amount Δθm are different. According to the embodiment, the idle running determiner57determines the rotation state of the motor10as the idle running state when the absolute value of the difference between the output shaft angle variation amount Δθs and the motor angle variation amount Δθm exceeds an idle determination threshold value θth. The idle determination threshold value θth is set to a small value (for example, 0.1°), which may be regarded that the output shaft angle variation amount Δθs and the motor angle variation amount Δθm match.

FIG. 4describes that the actual count value Cen is inputted to the idle running determiner57. However, the angle calculator51may calculate the motor angle θm and the calculated motor angle θm may be input to the idle running determiner57. The motor angle variation amount Δθm may be calculated as a difference value between a previous value of the motor angle θm and a present value of the motor angle θm. The motor angle variation amount Δθm may be calculated by converting the difference value between a previous value of the actual count value Cen and a present value of the actual count value Cen at the gear ratio.

As shown by an arrow sign Ym inFIG. 5, the motor10idles, a face inside of the reducer14and the output shaft15collide, and a collision sound occurs. Particularly, the collision sound may become big when the motor10idles at high speed in a case where the play is large. The face inside the reducer14and the output shaft15contact to each other, the collision sound does not occur while the motor10continually rotates in a similar direction, since the reducer14and the output shaft15integrally rotate.

According to the embodiment, the collision sound is suppressed by limiting the maximum value of the motor current and by suppressing the rotation speed of the motor10when the rotation state of the motor10is in the idle running state. According to the embodiment, the maximum value of the motor current is limited by limiting the duty.

The idle running determination process according to the embodiment will be explained with reference to a flowchart shown inFIG. 6. This process is executed in the ECU50in a predetermined period when the starter switch turns on.

In S101at first time, the idle running determiner57determines whether the energization flag turns on. The energization flag turns on when the driver request shift range changes. The energization flag turns off when the stationary energization control ends. When it is determined that the energization flag turns off (S101: NO), the following process is not executed. When it is determined that the energization flag turns on (S101: YES), the process shifts to S102.

In S102, the idle running determiner57determines whether the output shaft angle θs varies. When it is determined that the output shaft angle θs varies (S102: YES), the process shifts to S105. When it is determined that the output shaft angle θs does not vary (S102: NO), the process shifts to S103.

In S103, the idle running determiner57determines whether the output shaft angle variation amount Δθs and the motor angle variation amount Δθm match. When it is determined that the output shaft angle variation amount Δθs and the motor angle variation amount Δθm match (S103: YES), the rotation state of the motor10is not regarded as the idle running state, and the process shifts to S105. When it is determined that the output shaft angle variation amount Δθs and the motor angle variation amount Δθm do not match (S103: NO), the rotation state of the motor10is regarded as the idle running state, and the process shifts to S104.

In S104, the idle running determiner57causes the current limitation flag Flg_L to turn on, performs output to the duty limiter58. The duty limiter58limits the maximum value of the duty to the duty DH.

In S105, the current limitation flag Flg_L turns off. The duty limiter58does not perform the duty limitation.

The motor control process according to the embodiment will be explained with reference to a time chart ofFIG. 7. InFIG. 7, common time axis is set as horizontal axis.FIG. 7shows the driver request shift range, the energization flag, the motor angle θm, the output shaft angle θs, the duty, the motor current, and the current limitation flag Flg_L. An example that the motor10rotates in the forward direction to switch the shift range from the P range to the D range is explained. However, except for different points of the target count value Cen*, the direction of the motor10, the detail of the idle running determination and the current limitation or the like at the time of switching the other range is similar to this example.

InFIG. 7, a broken arrow shows the motor current, the duty, an output shaft angle θs_c, and a motor angle θm_c when the current limitation is not performed. Regarding to the motor angle θm and the output shaft angle θs inFIG. 7, the θ(Cen*) and the θ(ENth) are values obtained by converting the target count value Cen* and the angle determination threshold value ENth at gear ratio of the reducer14. The motor angle θm and the output shaft angle θs match when the motor shaft and the output shaft15integrally rotate. The motor angle θm and the output shaft angle θs are described so as to be slightly deviated from each other in the drawing, for explanation.

As shown inFIG. 7, at time x1, when the driver request shift range is changed from P range to D range, the energization flag is switched from off to on. When the driver request shift range is changed, the target count value Cen* is set corresponding to the driver request shift range. Immediate after time x1when the driver request shift range is changed, the difference between the target count value Cen* and the actual count value Cen is larger than the angle determination threshold ENth, so that the motor10is controlled by the position feedback control.

According to the embodiment, a responsiveness of the motor10is improved by performing the position feedback control. At beginning of starting the motor10, the difference between the target count value Cen* and the actual count value Cen is large, and the duty Du_a before the limitation becomes 100%. At the beginning of starting the motor10, the motor10rotates in a state that the load is substantially 0 when the reducer14and the output shaft15are separated. Therefore, as shown by the broken line, a large collision sound may occur due to the collision of the reducer14with output shaft15when the motor10rotates without the limitation of the duty.

According to the embodiment, the rotation state of the motor10is limited from time x1to time x2, corresponding to the idle running state. Specifically, the current limitation flag Flg_L turns on, and the maximum value of the duty is limited to the maximum duty DH. The motor current is limited. In comparison to the case where the duty is not limited, the rotation speed of the motor10is low, and the collision sound is suppressed. According to the embodiment, the motor current is limited until the idle running state ends.

At the time x2, when the idle running state ends and the gear of the reducer14abuts the output shaft15, the collision sound does not occur since the motor shaft and the output shaft15integrally rotates through the reducer14. Therefore, after the time x2, the current limitation flag Flg_L is set to turn off, the duty limitation is released, and the motor10is controlled by the position feedback control. The actual count value Cen approaches the target count value Cen*. It may be possible to improve the responsiveness by performing the feedback of the phase advance value Cen_pl after the phase advance filter process is executed to the phase advance value Cen_pl.

At time x3, when the difference between the target count value Cen* and the actual count value Cen becomes the angle determination threshold ENth or less, the control state of the motor10is switched from the position feedback control to the stationary phase energization control. The stationary phase energization enables the motor10to stop quickly.

While the energization duration Ta elapses until the time x4after the time x3, the stationary phase energization control continues. Hunting or the like is suppressed, so that it may be possible to surely stop the motor10. Therefore, it may be possible to fit the detent roller26to a desired recess.

At time x4when the energization duration Ta has elapsed from the start of the stationary phase energization control, the switching controller65changes the control state to energization off control. The switching controller65turns off the energization flag. The off-state of the energization flag continues until the driver request shift range is changed again, so that the energization off control continues as the control state of the motor10. Thereby, no power is supplied to the motor10except when the shift ranges are switched, so that it may be possible to reduce power consumption as compared to when power is supplied.

In the stationary phase energization control and the energization off control, the duty in the position feedback control is not employed. However, for convenience, the duty is described to be 0 in the drawing.

As shown by the motor angle θm and the output shaft angle θs inFIG. 7, the rotation state of the motor10is the idle running state from the time x1to the time x2, and a term from the time x1to the time x2is set to an idle running term. In the idle running term, the motor angle θm and the output shaft angle θs are different. In the idle running term, the motor angle variation amount Δθm does not equal to 0 since the motor angle θm varies. The output shaft angle variation amount Δθs nearly equal to 0 since the output shaft angle θs is constant. That is, in the idle running term, the motor angle variation amount Δθm and the output shaft angle variation amount Δθs are different.

The idle running term ends, the motor angle θm and the output shaft angle θs match, and the output shaft angle θs similarly varies corresponding to the variation of the motor angle θm. Hence, the motor angle variation amount Δθm and the output shaft angle variation amount Δθs match when the idle running state ends. According the embodiment, the rotation state of the motor10is determined as the idle running state when the motor angle variation amount Δθm and the output shaft angle variation amount Δθs are different. Thereby, it may be possible to appropriately determine whether the rotation state of the motor10is in the idle running state based on the motor angle θm and the output shaft angle θs.

As explained above, the shift range control apparatus40switches the shift range by controlling the drive of the motor10, and includes the idle running determiner57and the duty limiter58.

The idle running determiner57determines whether the rotation state is the idle running state that the motor10rotates within the range of the play existing between a motor shaft that is the rotation shaft of the motor10and the output shaft15to which the rotation of the motor10is transmitted.

The duty limiter58limits the current of the motor10in a case of determining as the idle running state.

Thereby, it may be possible to reduce the collision sound at the time of shift range switching.

The idle running determiner57determines whether the rotation state is the idle running state, based on the motor angle θm corresponding to the rotation of the motor10and the output shaft angle θs corresponding to the rotation of the output shaft15.

Specifically, the idle running determiner57determines the rotation state as the idle running state when the output shaft angle variation amount Δθs and the motor angle variation amount Δθm are different. Thereby, it may be possible to appropriately determine the idle running state, based on the motor angle θm and the output shaft angle θs.

Second Embodiment

FIG. 8shows a second embodiment of the present disclosure.

According the embodiment, the idle running determiner57determines the rotation state as the idle running state when the motor angle variation amount Δθm and the output shaft angle variation amount Δθs do not match.

In a case where the rotation state of the motor10is the idle running state, the rotation of the motor10is not transmitted to the output shaft15. Therefore, the output shaft15does not rotate, and the output shaft angle θs does not vary. According to the embodiment, the idle running determiner57determines that the rotation of them motor10is the idle running state when the output shaft15does not rotate and also the motor10rotates.

It may be possible to determine whether the output shaft15rotates, based on whether the output shaft angle θs varies. It may be possible to determine whether the motor10rotates, based on whether the motor angle θm varies. It may be possible to determine whether the output shaft angle θs and the variation of the motor angle θm vary, based on the output shaft angle variation amount Δθs and the motor angle variation amount Δθm, which being the difference value between the previous value and the present value. It may be possible to determine that the output shaft angle θs does not vary when the output shaft angle variation amount Δθs is equal to or less than a determination threshold value set to a value being close to 0. It may be possible to determine that the output shaft angle θs vary when the output shaft angle variation amount Δθs exceeds the determination threshold value set to a value being close to 0. It may be possible to determine whether to vary by employing the derivation of the output shaft angle θs or the like, instead of the output shaft angle variation amount Δθs. The motor angle θm may be treated similarly.

It may be determined whether the motor10rotates, based on the actual count value Cen before the conversion of the gear ratio with omitting the conversion at the gear ratio, instead of the motor angle θm being the value converted at the gear ratio.

The idle running determination process according to the embodiment will be explained with reference to a flowchart shown inFIG. 8. This process is executed in the ECU50in a predetermined period, similarly to the process ofFIG. 6.

The processes S201, S202, S204, and S205are similar to the processes S101, S102, S104, and S105inFIG. 6. Therefore, the detailed explanation will be omitted.

When it is determined that the output shaft angle θs does not vary (S202: NO), the process shifts to S203. In S203, it is determined whether the motor angle θm varies. When it is determined that the motor angle θm does not vary (S203: NO), the process shifts to S205. When it is determined that the motor angle θm varies (S203: YES), the process shifts to S204.

That is, according to the embodiment, when the output shaft angle θs does not vary (S202: NO) and also the motor angle θm varies (S203: YES), the rotation state of the motor10is regarded as the idle running state, the current limitation flag Flg_L turns on, and the duty is limited (S204).

As shown by the motor angle θm and the output shaft angle θs inFIG. 7, the motor10rotates and the motor angle θm varies in a term of the idle running. By contrast, the output shaft15does not rotate and the output shaft angle θs is constant in the term of the idle running. The idle running term ends, and the output shaft15and the motor shaft integrally rotate. Therefore, the output shaft angle θs and the motor angle θm similarly vary. Accordingly, it may be possible to appropriately determine whether the rotation state of the motor10is the idle running state, based on the motor angle θm and the output shaft angle θs, even when determining as the embodiment.

According to the embodiment, the idle running determiner57determines the rotation state as the idle running state when the output shaft angle θs does not vary and also the motor angle θm varies. Thereby, it may be possible to appropriately determine the idle running state, based on the output shaft angle θs and the motor angle θm.

The effect similarly to the embodiment described above will be provided.

Other Embodiments

According to the embodiment described above, the motor is a permanent magnet three-phase brushless motor. According to the other embodiments, the motor may be employed as not only the permanent magnet three-phase brushless motor but also any motor capable of providing the current limitation or the like. According to the embodiment described above, two winding groups are placed in the motor. According to the other embodiments, the number of sets of windings in the motor may be one, or three or more.

According to the embodiment described above, the position feedback control performs a 120° energization square-wave control scheme. According to the other embodiments, the position feedback control may perform a 180° energization square-wave control scheme. The control scheme is not limited to square-wave control. PWM control with triangle wave comparison or instantaneous vector selection is also possible.

According to the embodiment described above, the motor control state is switched between the position feedback control and the stationary phase energization control. According to the other embodiments, the motor drive controller may set at least one of the position feedback control or the stationary phase energization control to a different control state. According to the embodiment described above, the position feedback control and the stationary phase energization control are switched. According to the embodiment, it may control the drive of the motor in one control state such as the position feedback control, for example, without switching the control state of the motor.

According to the embodiment described above, the motor current is limited by limiting the duty. According to the other embodiments, the motor may be limited by limiting a parameter except for the duty, for example, a current command value, a voltage command value, or a torque command value, or the like.

According to the embodiment described above, the encoder is employed as rotation angle sensor detecting the motor angle of the motor. According to the other embodiments, the rotation angle sensor may be employed as not only the encoder but also any other devices such as a resolver or the like. According to the embodiment described above, phase advance filter process is performed to the count value of the encoder, the count value of the encoder is used for the position feedback control. According to the other embodiments, the position feedback control may be performed by using the rotation angle itself of the motor, or other values convertible to the motor rotation angle, other than the encoder count. Selection of a stationary phase in the stationary phase energization control may be treated similarly. According to the other embodiments, the phase advance filter process may be omitted.

According to the embodiment described above, four recesses are placed in the detent plate. According to the other embodiments, the number of the recess is not limited to four, and may be any number. For example, the number of the recess of the detent plate may be two, and P range and not P range may be switched. The shift range switching mechanism and the parking lock mechanism or the like may be different from the embodiment described above.

As described above, the reducer is placed between the motor shaft of the motor and the output shaft. According to the other embodiment, the reducer between the motor shaft of the motor and the output shaft may be omitted, and a machine except for the reducer may be placed. That is, according to the embodiment, it is mainly explained that “the play” between the motor shaft and the output shaft exists between the output shaft and the gear of the reducer. However, “the play” can be regarded as a total of the play, clank, or the like, existing between the motor shaft and the output shaft.

According to the other embodiments, it may determine the idle running determination, by not only the determination method according to the embodiment described above but also any method, based on the output shaft angle and the motor angle. In the idle running determination process according to the first embodiment, the process of S102may be omitted.

According to the embodiment described above, it is set to match the motor shaft angle converted at the gear ratio to the output shaft angle. According to the other embodiments described above, it may match the output shaft angle converted at the gear ratio to the motor shaft angle. Conveniently, the conversion at the gear ratio may be omitted when the reducer is not placed in the motor shaft and the output shaft, or the like.

It is noted that a flowchart or the processing of the flowchart in the present application includes multiple steps (also referred to as sections), each of which is represented, for instance, as S101. Further, each step can be divided into several sub-steps while several steps can be combined into a single step.

In the above, the embodiment, the configuration, an aspect of the shift range apparatus according to the present disclosure are exemplified. However, the present disclosure is not limited to every embodiment, every configuration and every aspect related to the present disclosure are exemplified. For example, the field of the embodiment, the configuration, the aspect relate to the present disclosure includes the embodiment, the configuration, the aspect obtained by accordingly combining each technical part disclosed in different embodiment, configuration and aspect.