JP6323304B2 - Range switching control device - Google Patents

Description

  The present invention relates to a range switching control device that switches a shift range using a motor as a drive source.

  In recent years, the number of cases in which a mechanical drive system is changed to a system that is electrically driven by a motor has been increasing in order to satisfy the demands for space saving, assembling, and control. . As an example, there is one in which a range switching mechanism of an automatic transmission of a vehicle is driven by a motor.

  In such a system, for example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-32176), a target range (target shift) according to a driver's range switching operation (shift lever operation or the like). In some cases, the shift range is switched to the target range by switching the range) and rotating the motor to the rotational position corresponding to the target range.

  Further, in Patent Document 1, when the operation frequency of the range switching operation exceeds a predetermined frequency (when the number of times that the range switching operation is continuously performed at a short operation interval reaches a predetermined value), the heat generated by the motor. Judging that there is a possibility that the temperature rise may exceed the allowable level, the motor is prohibited from being energized.

JP 2008-32176 A

  By the way, the motor has a characteristic that when the power supply voltage decreases or the temperature of the coil (winding) increases and the resistance increases, the current flowing through the coil decreases and the torque decreases. If the torque that can be generated by the motor becomes lower than the allowable lower limit due to a decrease in power supply voltage or a current decrease due to a coil temperature increase (resistance increase), the shift range can be switched normally. For example, there is a possibility that a switching abnormality such as a motor stopping while switching the shift range to the target range may occur.

  Further, the technique of Patent Document 1 does not take into account such a shortage of torque due to a decrease in the current of the motor, and simply prohibits energization of the motor when the operation frequency of the range switching operation exceeds a predetermined frequency. It is. For this reason, the motor may be prohibited from being energized in spite of the fact that torque that can normally switch the shift range can be generated, and switching of the shift range is prohibited more than necessary. There is a possibility.

  Therefore, the problem to be solved by the present invention is to prevent the shift range switching from being prohibited more than necessary while preventing the occurrence of shift range switching abnormality due to insufficient motor torque. The object is to provide a range switching control device.

  In order to solve the above problems, the present invention provides a range switching mechanism (11) for switching a shift range between a plurality of ranges including a P range using a motor (12) as a drive source, and a motor according to a driver's switching operation. In a range switching control device comprising a control means (41) for rotationally driving (12) to switch the shift range, a voltage detection means (33) for detecting the power supply voltage of the motor (12) and a motor (12) Current detection means (34) for detecting a flowing current, switching prohibition means (41) for prohibiting shift range switching when the power supply voltage detected by the voltage detection means (33) is lower than a predetermined voltage value, and voltage detection The shift range is temporarily switched when the power supply voltage detected by the means (33) is equal to or higher than a predetermined voltage value and the current detected by the current detection means (34) is smaller than the predetermined current value. It is obtained by a structure in which a switching restriction means for switching restriction prohibiting (41) on.

  In this configuration, when the power supply voltage is lower than the predetermined voltage value, the torque that can be generated by the motor is reduced to the allowable lower limit value (for example, the lower limit value of the torque at which the shift range can be switched normally, It can be determined that the torque is insufficient and the shift range is switched. In addition, when the power supply voltage is equal to or higher than the predetermined voltage value and the motor current (current flowing through the motor) is smaller than the predetermined current value, the torque that can be generated by the motor is reduced by the current decrease due to the coil temperature increase (resistance increase). It can be determined that the torque is insufficient to be lower than the value, and the switching restriction for temporarily prohibiting the shift range switching can be performed. Thereby, it is possible to prevent occurrence of shift range switching abnormality (for example, abnormality in which the motor stops while switching the shift range to the target range) due to insufficient motor torque. Further, when the power supply voltage is equal to or higher than the predetermined voltage value and the motor current is smaller than the predetermined current value, it is determined that the current is decreased due to the temperature rise of the coil, and the shift range switching (motor energization) is temporarily prohibited. By performing the switching restriction, it is possible to prevent the motor (coil) from being overheated and to cool the motor (coil) to solve the torque shortage.

  On the other hand, when it is other than the above (that is, when the power supply voltage is equal to or higher than the predetermined voltage value and the motor current is equal to or higher than the predetermined current value), it is determined that the torque capable of normally switching the shift range is generated. Shift range switching is not prohibited (permitted). This avoids prohibiting shift range switching more than necessary (prohibiting shift range switching despite the fact that torque that can be switched normally can be generated). Can do.

FIG. 1 is a perspective view of a range switching mechanism in Embodiment 1 of the present invention. FIG. 2 is a diagram showing a schematic configuration of the range switching control system. FIG. 3 is a flowchart showing the flow of processing of the torque shortage determination routine. FIG. 4 is a flowchart showing the flow of processing of the switching determination routine. FIG. 5 is a flowchart showing a flow of processing of the switching restriction processing routine of the first embodiment. FIG. 6 is a time chart showing the behavior of the motor current. FIG. 7 is a diagram conceptually illustrating an example of a predetermined time map. FIG. 8 is a flowchart showing the flow of processing of the switching restriction processing routine of the second embodiment.

  Hereinafter, some embodiments embodying the mode for carrying out the present invention will be described.

A first embodiment of the present invention will be described with reference to FIGS.
First, the configuration of the range switching control system will be described based on FIG. 1 and FIG.
As shown in FIG. 1, the range switching mechanism 11 uses a P range (parking range), an R range (reverse range), and an N range (neutral range) as the shift range of an automatic transmission 27 (see FIG. 2) mounted on the vehicle. ) And D range (drive range). The motor 12 serving as a drive source for the range switching mechanism 11 is constituted by, for example, a switched reluctance motor. The motor 12 incorporates a speed reduction mechanism 26 (see FIG. 2), and a manual shaft 13 of the range switching mechanism 11 is connected to the output shaft 12a (see FIG. 2). A detent lever 15 is fixed to the manual shaft 13.

  A manual valve 32 that moves linearly according to the rotation of the detent lever 15 is connected to the detent lever 15, and the manual valve 32 switches a hydraulic circuit (not shown) inside the automatic transmission 27 to shift the detent lever 15. The range is switched.

  Further, an L-shaped parking rod 18 is fixed to the detent lever 15, and a cone 19 provided at the tip of the parking rod 18 is in contact with the lock lever 21. The lock lever 21 moves up and down around the shaft 22 in accordance with the position of the cone 19 to lock / unlock the parking gear 20. The parking gear 20 is provided on the output shaft of the automatic transmission 27, and when the parking gear 20 is locked by the lock lever 21, the driving wheel of the vehicle is held in a stopped state (parking state).

  On the other hand, a detent spring 23 for holding the detent lever 15 in each of the P, R, N, and D ranges is fixed to the support base 17, and each of the P, R, N, and D range holding recesses is provided in the detent lever 15. 24 is formed. When the engaging portion 23a provided at the tip of the detent spring 23 is fitted in each range holding recess 24 of the detent lever 15, the detent lever 15 is held at the position of each range. A detent mechanism 14 (moderation mechanism) for engaging and holding the rotational position of the detent lever 15 at each range position from the detent lever 15 and the detent spring 23 (that is, holding the range switching mechanism 11 at each range position). Is configured.

  In the P range, the parking rod 18 moves in a direction approaching the lock lever 21, the thick part of the cone 19 pushes up the lock lever 21, and the convex portion 21 a of the lock lever 21 fits into the parking gear 20. The gear 20 is locked. Accordingly, the output shaft (drive wheel) of the automatic transmission 27 is held in a locked state (parking state).

  On the other hand, in the ranges other than the P range, the parking rod 18 moves away from the lock lever 21, the thick part of the cone 19 comes out of the lock lever 21, and the lock lever 21 is lowered. Thereby, the convex portion 21a of the lock lever 21 is released from the parking gear 20, the lock of the parking gear 20 is released, and the output shaft of the automatic transmission 27 is held in a rotatable state (running state).

  As shown in FIG. 2, the rotation shaft 16 that detects the rotation angle (rotation position) of the manual shaft 13 is provided on the manual shaft 13 of the range switching mechanism 11. The rotation sensor 16 is configured by a sensor (for example, a potentiometer) that outputs a voltage corresponding to the rotation angle of the manual shaft 13, and the actual shift range depends on the output voltage of the P range, R range, N range, and D range. You can check which one it is.

  As shown in FIG. 2, the motor 12 is provided with an encoder 46 for detecting the rotation angle (rotation position) of the rotor. The encoder 46 is constituted by, for example, a magnetic rotary encoder, and is configured to output A-phase and B-phase pulse signals at predetermined angles in synchronization with the rotation of the rotor of the motor 12. The microcomputer 41 (control means) of the range switching control circuit 42 counts both rising / falling edges of the A-phase signal and B-phase signal output from the encoder 46, and the count value (hereinafter referred to as “encoder count value”). The motor 12 is rotationally driven by switching the energized phase of the motor 12 in a predetermined order by the motor driver 37 in accordance with the above. Two combinations of three-phase (U-phase, V-phase, and W-phase) windings of the motor 12 and the motor driver 37 are provided. Even if one of the systems fails, the motor 12 is driven to rotate by the other system. It may be configured as possible.

  While the motor 12 is rotating, the rotation direction of the motor 12 is determined based on the generation order of the A-phase signal and the B-phase signal. In the normal rotation (P range → D range rotation direction), the encoder count value is counted up and reverse rotation is performed. In the rotation direction (from D range to P range), the encoder count value is counted down. As a result, even if the motor 12 rotates in either the forward rotation or the reverse rotation, the correspondence relationship between the encoder count value and the rotation angle of the motor 12 is maintained. However, the rotational position of the motor 12 is detected based on the encoder count value, and the motor 12 can be rotationally driven by energizing the winding of the phase corresponding to the rotational position.

  The range switch control circuit 42 receives a signal of the shift lever operation position detected by the shift switch 44. Thereby, the microcomputer 41 of the range switching control circuit 42 switches the target range (target shift range) according to the driver's shift lever operation and the like, and the motor 12 is driven to rotate according to the target range to set the shift range. The actual shift range after switching is displayed on a range display section 45 provided on an instrument panel (not shown).

  A power supply voltage is supplied to the range switching control circuit 42 from a battery 50 (power source) mounted on the vehicle via a power relay 51. The power relay 51 can be turned on / off by manually operating on / off of an IG switch 52 (ignition switch) that is a power switch. When the IG switch 52 is turned on, the power supply relay 51 is turned on and the power supply voltage is supplied to the range switching control circuit 42. When the IG switch 52 is turned off, the power supply relay 51 is turned off and goes to the range switching control circuit 42. Is turned off.

  In addition, the range switching control circuit 42 is provided with a voltage sensor 33 (voltage detection means) for detecting a power supply voltage and a current sensor 34 (current detection means) for detecting a motor current (current flowing through the motor 12). . The current sensor 34 detects, as the motor current, for example, a current that flows through a collective portion where coils of each phase are connected, a current supplied to the motor driver 37, or the like. The voltage sensor 33 and the current sensor 34 may be provided separately from the range switching control circuit 42.

  When the target range is switched by the driver's shift lever operation or the like, the microcomputer 41 of the range switching control circuit 42 changes the target rotational position (target count value) accordingly. Then, by sequentially switching the energized phase of the motor 12 based on the encoder count value, feedback control for rotating the motor 12 to the target rotational position corresponding to the target range is executed, and the shift range is switched to the target range (range switching). The switching position of the mechanism 11 is switched to the target range position).

  By the way, the motor 12 has a characteristic that when the power supply voltage decreases or the resistance of the coil (winding) increases and the resistance increases, the current flowing in the coil decreases and the torque decreases. . If the torque that can be generated by the motor 12 becomes lower than the allowable lower limit due to such a decrease in power supply voltage or a current decrease due to a coil temperature increase (resistance increase), the shift range is switched normally. There is a possibility that the motor 12 will stop while the shift range is switched to the target range.

Therefore, in the first embodiment, the following control is performed by executing the routines of FIGS. 3 to 5 described later by the microcomputer 41 of the range switching control circuit 42.
When the power supply voltage detected by the voltage sensor 33 is lower than the predetermined voltage value, the torque that can be generated by the motor 12 is reduced to an allowable lower limit (for example, the lower limit of the torque that can normally switch the shift range) due to the current drop caused by the drop in the power supply voltage. It is determined that the torque is insufficient, which is lower than the value or a value slightly higher than that, and switching of the shift range is prohibited.

  Further, when the power supply voltage detected by the voltage sensor 33 is equal to or higher than a predetermined voltage value and the motor current detected by the current sensor 34 is smaller than the predetermined current value, the torque that can be generated by the motor 12 due to the current decrease due to the temperature rise of the coil. Is determined to be in a state of torque shortage that becomes lower than the allowable lower limit value, and switching restriction is temporarily performed to prohibit switching of the shift range.

  When the number of switching operations of the driver reaches a predetermined number during the switching restriction, switching of the shift range is permitted only at that time, and then switching of the shift range is prohibited again. However, when the number of times the shift range switching is permitted during the switching limit reaches a predetermined upper limit number, the shift range switching is not permitted any more.

  Thereafter, when the state in which the motor 12 is not energized during the switching limit (the state in which the shift range is not switched) continues for a predetermined time necessary for cooling the motor 12, the motor 12 is cooled and the torque shortage is resolved ( It is determined that a torque capable of normally switching the shift range has been generated), and the switching restriction is terminated.

  The processing contents of the routines of FIGS. 3 to 5 executed by the microcomputer 41 of the range switching control circuit 42 in the first embodiment will be described below. These routines serve as switching prohibiting means and switching limiting means in the claims.

[Torque shortage judgment routine]
The torque shortage determination routine shown in FIG. 3 is repeatedly executed at predetermined intervals by the microcomputer 41 during the power-on period of the range switching control circuit 42. When this routine is started, first, in step 101, it is determined whether or not the power supply voltage detected by the voltage sensor 33 is equal to or higher than a predetermined voltage value. Here, the predetermined voltage value is set to a voltage value at which the torque that can be generated by the motor 12 becomes an allowable lower limit value, for example.

  When it is determined in step 101 that the power supply voltage is lower than the predetermined voltage value, the torque that can be generated by the motor 12 is lower than the allowable lower limit value due to the current decrease due to the power supply voltage decrease. It is judged that. In this case, the process proceeds to step 102, where the switching prohibition flag is set to ON (on) to prohibit shift range switching (energization of the motor 12). Thereafter, the process proceeds to step 103, and the switching restriction flag is reset to OFF.

  On the other hand, if it is determined in step 101 that the power supply voltage is equal to or higher than the predetermined voltage value, the process proceeds to step 104, the switch prohibition flag is reset to OFF, and then the process proceeds to step 105, where stop control is being performed. Determine whether or not. As shown in FIG. 6, when the shift range is switched, first, the energized phase of the motor 12 is sequentially switched to execute rotation control for rotating the motor 12 toward the target rotation position corresponding to the target range, and then the motor. The stop control is executed to fix the 12 energized phases (stop the switching of the energized phases) and stop the motor 12 at the target rotational position. Since the motor current is more stable during the stop control than during the rotation control, in this embodiment, the motor current is detected by the current sensor 34 during the stop control.

  If it is determined in step 105 that stop control is being performed, the process proceeds to step 106, where it is determined whether or not the motor current detected by the current sensor 34 is smaller than a predetermined current value. Here, for example, the predetermined current value is set to a current value such that the torque that can be generated by the motor 12 is an allowable lower limit value. Further, when switching from the P range to the NotP range (a range other than the P range) (when unlocking the parking gear 20), switching from the NotP range to the P range (when locking the parking gear 20) is performed. , Big torque is needed. Therefore, in this embodiment, when the current shift range is the P range, the predetermined current value (threshold for determining torque shortage) is set to a larger value than when the current shift range is the NotP range.

  If it is determined in step 101 that the power supply voltage is equal to or higher than the predetermined voltage value, and if it is determined in step 106 that the motor current is smaller than the predetermined current value, the current due to the coil temperature rise (resistance increase) It is determined that the torque that can be generated by the motor 12 is lower than the allowable lower limit due to the decrease, and that the torque is insufficient. In this case, the routine proceeds to step 107, where the switching restriction flag is set to ON, and the switching restriction that temporarily prohibits the shift range switching (energization of the motor 12) is performed. Further, a warning lamp (not shown) is turned on or blinked, or a warning is displayed on a warning display (not shown), or a warning sound or sound is given to warn the driver. Anyway.

  On the other hand, if it is determined in step 101 that the power supply voltage is equal to or higher than the predetermined voltage value, and if it is determined in step 106 that the motor current is equal to or higher than the predetermined current value, the shift range can be switched normally. It is determined that the torque can be generated. In this case, the process proceeds to step 108, where the switching restriction flag is reset to OFF, and switching of the shift range is not prohibited (permitted).

  Thereafter, if it is determined in step 105 that the stop control is not being performed, the process proceeds to step 109, where it is determined whether the switching limit flag is ON, and it is determined that the switching limit flag is OFF. In this case, this routine is terminated while the switching restriction flag is kept OFF.

  On the other hand, if it is determined in step 109 that the switch restriction flag is ON, the process proceeds to step 110, and a state in which the motor 12 is not energized (a state without shift range switching) is necessary for cooling the motor 12. It is determined whether or not it has continued for a predetermined time.

  In this case, the predetermined time according to the power supply voltage and the motor current is set with reference to the predetermined time map shown in FIG. In general, the lower the power supply voltage, the smaller the amount of heat generated by the coil, the smaller the temperature difference between the temperature of the motor 12 (coil temperature) and the ambient temperature, and the slower the cooling of the motor 12. In addition, the smaller the motor current, the higher the temperature of the motor 12 (coil temperature), and the longer it takes to cool the motor 12. Considering such characteristics, the predetermined time map shown in FIG. 7 shows that the motor current is the same, the lower the power supply voltage is, the longer the predetermined time is. If the power supply voltage is the same, the motor current is The smaller the is, the longer the predetermined time is set. This predetermined time map is created in advance based on test data, design data, and the like, and is stored in the ROM of the microcomputer 41.

  If it is determined in step 110 that the motor 12 is not energized for a predetermined time required for cooling the motor 12, this routine is terminated while the switching restriction flag is kept ON.

  Thereafter, when it is determined in step 110 that the state in which the motor 12 is not energized has continued for a predetermined time necessary for cooling the motor 12, the state in which the motor 12 has been cooled and the torque shortage has been eliminated (the shift range is changed). It is determined that the torque that can be switched normally can be generated). In this case, the process proceeds to step 111, the switching restriction flag is reset to OFF, and the switching restriction is terminated.

[Switching judgment routine]
The switching determination routine shown in FIG. 4 is repeatedly executed at a predetermined cycle by the microcomputer 41 during the power-on period of the range switching control circuit 42. When this routine is started, first, in step 201, a switching restriction processing routine of FIG. 5 described later is executed to set the switching temporary prohibition flag to ON or reset to OFF.

  Thereafter, the process proceeds to step 202, where it is determined whether or not the switching temporary prohibition flag is ON. If it is determined in this step 202 that the switching temporary prohibition flag is OFF, the process proceeds to step 203 and the switching is prohibited. It is determined whether or not the prohibition flag is ON.

  If it is determined in step 202 that the switching temporary prohibition flag is OFF, and if it is determined in step 203 that the switching prohibition flag is OFF, the process proceeds to step 204 where the driver performs a switching operation (shift lever). It is determined whether or not an operation has been performed.

  If it is determined in step 204 that the switching operation has been performed, the process proceeds to step 205 to switch the target range to the required range (the shift range selected by the switching operation). Thereby, the motor 12 is rotationally driven to the target rotation position corresponding to the target range, and the shift range is switched to the target range.

  On the other hand, if it is determined in step 204 that the switching operation has not been performed, the process proceeds to step 206, where the target range is held at the current range (current shift range).

  On the other hand, if it is determined in step 202 that the switching temporary prohibition flag is ON, or if it is determined in step 203 that the switching prohibition flag is ON, the driver performs a switching operation. Regardless of whether or not it has been performed, the process proceeds to step 206, and the target range is held in the current range. This prohibits shift range switching.

[Switching restriction routine]
The switching restriction processing routine shown in FIG. 5 is a subroutine executed in step 201 of the switching determination routine of FIG. When this routine is started, first, at step 301, it is determined whether or not the switching restriction flag is ON.

  If it is determined in step 301 that the switching restriction flag is OFF, the process proceeds to step 302, where the count value of the switching operation counter that counts the number of switching operations of the driver is reset to “0”. In step 303, the count value of the switching permission counter that counts the number of times that switching of the shift range is permitted is reset to "0". Thereafter, the process proceeds to step 310, and the switching temporary prohibition flag is reset to OFF.

  On the other hand, if it is determined in step 301 that the switching restriction flag is ON, the process proceeds to step 304 to determine whether or not a switching operation (shift lever operation or the like) has been performed by the driver. If it is determined that the process is not performed, this routine is terminated as it is.

  Thereafter, when it is determined in step 304 that the switching operation has been performed, the process proceeds to step 305, in which the count value of the switching operation counter that counts the number of switching operations of the driver is set to a predetermined number (for example, 3 to 5 times). ) Determine whether it is above.

  If it is determined in step 305 that the count value of the switching operation counter is smaller than the predetermined number (when the number of switching operations has not reached the predetermined number), the process proceeds to step 306 and the count value of the switching operation counter is reached. Is incremented by "1", the process proceeds to step 311 to set the switching temporary prohibition flag to ON.

  Thereafter, when it is determined in step 305 that the count value of the switching operation counter is equal to or greater than the predetermined number of times (when the number of switching operations reaches the predetermined number of times), the process proceeds to step 307 to allow shift range switching. It is determined whether or not the count value of the switching permission counter that counts the number of times is equal to or greater than the upper limit number.

  If it is determined in step 307 that the count value of the switching permission counter is smaller than the upper limit number (if the number of times the shift range switching has been permitted has not reached the upper limit number), the process proceeds to step 308 and the switching operation is performed. After resetting the count value of the counter to “0”, the process proceeds to step 309 and the count value of the switching permission counter is incremented by “1”. Thereafter, the process proceeds to step 310, and the switching temporary prohibition flag is reset to OFF. Thus, when the number of switching operations by the driver reaches a predetermined number (every time the driver reaches the predetermined number), switching of the shift range is permitted only at that time.

  Thereafter, when it is determined in step 307 that the count value of the switching permission counter is equal to or greater than the upper limit number (when the number of times the shift range is permitted to be switched reaches the upper limit number), the process proceeds to step 311 and the switching is performed. Set the temporary prohibition flag to ON. As a result, when the number of times the shift range switching is permitted reaches the upper limit number, the shift range switching is not permitted any more.

  In the first embodiment described above, when the power supply voltage detected by the voltage sensor 33 is lower than the predetermined voltage value, the torque that can be generated by the motor 12 becomes lower than the allowable lower limit value due to the current drop due to the power supply voltage drop. Judging that the torque is insufficient, switching of the shift range is prohibited. Further, when the power supply voltage detected by the voltage sensor 33 is equal to or higher than a predetermined voltage value and the motor current detected by the current sensor 34 is smaller than the predetermined current value, the torque that can be generated by the motor 12 due to the current decrease due to the temperature rise of the coil. Is determined to be in a state of torque shortage that is lower than the allowable lower limit value, and the switching restriction is temporarily performed to prohibit the shift range switching. Thereby, it is possible to prevent the occurrence of shift range switching abnormality (for example, abnormality that stops the motor 12 while switching the shift range to the target range) due to insufficient torque of the motor 12. In addition, when the power supply voltage is equal to or higher than the predetermined voltage value and the motor current is smaller than the predetermined current value, it is judged that the current is decreased due to the coil temperature increase (resistance increase), and the shift range switching is temporarily prohibited. By performing the restriction, it is possible to prevent the motor 12 (coil) from being overheated and to cool the motor 12 (coil) to solve the torque shortage.

  On the other hand, when the power supply voltage is equal to or higher than the predetermined voltage value and the motor current is equal to or higher than the predetermined current value, it is determined that the torque that can normally switch the shift range can be generated, and switching of the shift range is not prohibited (permitted). To do). This avoids prohibiting shift range switching more than necessary (prohibiting shift range switching despite the fact that torque that can be switched normally can be generated). Can do.

  In the first embodiment, when the number of switching operations of the driver reaches a predetermined number while switching is limited, switching of the shift range is permitted only at that time, and then switching of the shift range is prohibited again. ing. As a result, until the number of switching operations of the driver reaches the predetermined number, switching of the shift range is prohibited, and the driver is made aware that the switching of the shift range is limited due to insufficient torque of the motor 12. be able to. On the other hand, when the number of switching operations of the driver reaches a predetermined number (that is, when the driver repeats the switching operation many times), it is determined that the urgency is high and switching of the shift range is permitted. Thus, the shift range can be switched.

  However, in the first embodiment, when the number of times the shift range switching is permitted during the switching limit reaches a predetermined upper limit number, the shift range switching is not permitted any more. In this way, it is possible to prevent the shift of the shift range from being permitted many times during the switching restriction due to the driver's nasty operation (repeated operation), and delay the cooling of the motor 12 (resolving torque shortage). Can be prevented.

  In the first embodiment, when the motor 12 is not energized during the switching limit (the shift range is not switched) continues for a predetermined time necessary for cooling the motor 12, the motor 12 is cooled and the torque is insufficient. It is determined that the state has been resolved (a state in which a torque capable of normally switching the shift range can be generated), and the switching restriction is terminated. As a result, when the motor is cooled and the torque shortage is resolved (a state in which torque that can normally switch the shift range can be generated), switching of the shift range can be permitted.

  Furthermore, in the first embodiment, the predetermined time is set according to the power supply voltage and the motor current. At this time, the predetermined time is lengthened as the power supply voltage is low, and the predetermined time is lengthened as the motor current is small. ing. Accordingly, the lower the power supply voltage, the smaller the amount of heat generated by the coil, the smaller the temperature difference between the temperature of the motor 12 (coil temperature) and the ambient temperature, and the slower cooling of the motor 12, The predetermined time can be lengthened. In addition, the smaller the motor current is, the higher the temperature of the motor 12 (coil temperature) is, and the predetermined time can be increased corresponding to the longer time required for the motor 12 to cool. As a result, the predetermined time required for cooling the motor 12 can be set appropriately, and the predetermined time is prevented from becoming longer than necessary, and the period for performing the switching restriction is prevented from becoming excessively long. be able to.

  In the first embodiment, when the current shift range is the P range, a predetermined current value (threshold for determining torque shortage) is greater than when the current shift range is the NotP range (a range other than the P range). ) Is set to a large value. Thus, when switching from the P range to the NotP range, a predetermined current value (threshold value for determining torque shortage) corresponding to the fact that a larger torque is required than when switching from the NotP range to the P range. Can be increased.

  Next, Embodiment 2 of the present invention will be described with reference to FIG. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

  In the second embodiment, the microcomputer 41 of the range switching control circuit 42 executes a switching restriction processing routine of FIG. 8 described later, so that when the duration of the switching operation of the driver reaches a predetermined time during the switching restriction, Only at that time switching of the shift range is permitted, and then switching of the shift range is prohibited again. However, when the number of times the shift range switching is permitted during the switching limit reaches a predetermined upper limit number, the shift range switching is not permitted any more.

The processing contents of the switching restriction processing routine of FIG. 8 executed by the microcomputer 41 of the range switching control circuit 42 in the second embodiment will be described below.
In the switching restriction processing routine shown in FIG. 8, first, in step 401, it is determined whether or not the switching restriction flag is ON. If it is determined in step 401 that the switching restriction flag is OFF, the process proceeds to step 402, the count value of the switching permission counter is reset to “0”, and then the process proceeds to step 407, where the switching temporary prohibition flag is set. Reset to OFF.

  On the other hand, if it is determined in step 401 that the switching restriction flag is ON, the process proceeds to step 403, where it is determined whether or not a switching operation (shift lever operation or the like) has been performed by the driver. If it is determined that the process is not performed, this routine is terminated as it is.

Thereafter, if it is determined in step 403 that the switching operation has been performed, the process proceeds to step 404 where the duration of the driver's switching operation (for example, the time during which the shift lever is held) is predetermined. It is determined whether it is time (for example, 3 sec) or more.
If it is determined in step 405 that the duration of the switching operation is shorter than the predetermined time, the process proceeds to step 408, and the switching temporary prohibition flag is set to ON.

  Thereafter, when it is determined in step 404 that the duration of the switching operation is equal to or longer than the predetermined time (when the duration of the switching operation has reached the predetermined time), the process proceeds to step 405 and the count value of the switching permission counter is reached. Whether or not is equal to or greater than the upper limit number.

  If it is determined in step 405 that the count value of the switching permission counter is smaller than the upper limit number (if the number of times the shift range switching is permitted has not reached the upper limit number), the process proceeds to step 406 and switching permission is performed. After the count value of the counter is incremented by “1”, the process proceeds to step 407 and the switching temporary prohibition flag is reset to OFF. Thereby, when the duration of the switching operation of the driver reaches a predetermined time (every time it reaches the predetermined time), switching of the shift range is permitted only at that time.

  Thereafter, when it is determined in step 405 that the count value of the switching permission counter is equal to or greater than the upper limit number (when the number of times the shift range switching is permitted reaches the upper limit number), the process proceeds to step 408 and the switching is performed. Set the temporary prohibition flag to ON. As a result, when the number of times the shift range switching is permitted reaches the upper limit number, the shift range switching is not permitted any more.

  In the second embodiment described above, when the duration of the switching operation of the driver reaches a predetermined time while the switching is restricted, switching of the shift range is permitted only at that time, and thereafter switching of the shift range is prohibited again. I am doing so. As a result, if the duration of the switching operation of the driver does not reach the predetermined time, switching of the shift range is prohibited, and it is indicated to the driver that switching of the shift range is limited due to insufficient torque of the motor 12. Can be recognized. On the other hand, when the duration of the switching operation of the driver reaches a predetermined time (that is, when the driver continues the switching operation for a long time), it is determined that the urgency is high, and switching of the shift range is permitted. The shift range can be switched.

  When the number of switching operations of the driver reaches a predetermined number during the switching restriction by combining the first embodiment and the second embodiment, the duration of the switching operation of the driver is set to the predetermined time during the switching restriction. When this is reached, switching of the shift range may be permitted. Also in this case, when the number of times the shift range switching is permitted during the switching limit reaches a predetermined upper limit number, it is preferable not to permit the shift range switching any more.

  Further, in each of the first and second embodiments, the present invention is applied to a system including a range switching mechanism that switches the shift range among the four ranges of the P range, the R range, the N range, and the D range. For example, the present invention may be applied to a system including a range switching mechanism that switches the shift range between two ranges of the P range and the NotP range. Or you may apply this invention to the system provided with the range switching mechanism which switches a shift range between three ranges or between five or more ranges.

  In addition, the present invention is not limited to automatic transmissions (AT, CVT, DCT, etc.), and may be applied to a system including a range switching mechanism that switches the shift range of a transmission (reduction gear) for an electric vehicle. Various modifications can be made without departing from the scope of the invention.

  DESCRIPTION OF SYMBOLS 11 ... Range switching mechanism, 12 ... Motor, 33 ... Voltage sensor (voltage detection means), 34 ... Current sensor (current detection means), 41 ... Microcomputer (control means, switching prohibition means, switching restriction means)

Claims (8)

A range switching mechanism (11) for switching the shift range between a plurality of ranges including the P range using the motor (12) as a drive source, and the motor (12) is rotationally driven in response to a driver's switching operation to shift the shift range. In a range switching control device comprising a control means (41) for switching between
Voltage detection means (33) for detecting a power supply voltage of the motor (12);
Current detection means (34) for detecting current flowing in the motor (12);
Switching prohibiting means (41) for prohibiting switching of the shift range when the power supply voltage detected by the voltage detecting means (33) is lower than a predetermined voltage value;
Temporarily prohibiting switching of the shift range when the power supply voltage detected by the voltage detection means (33) is not less than the predetermined voltage value and the current detected by the current detection means (34) is smaller than the predetermined current value. And a switching restriction means (41) for performing switching restriction.   The switching restriction means (41) permits the shift range to be switched when the number of switching operations of the driver reaches a predetermined number during the switching restriction, and then prohibits the shift range switching again. The range switching control device according to claim 1.   The switching restriction means (41) permits the shift range to be switched when the duration of the switching operation of the driver reaches a predetermined time during the switching restriction, and thereafter prohibits the shift range switching again. The range switching control device according to claim 1 or 2, wherein   The switching restricting means (41) does not permit the switching of the shift range any more when the number of times the switching of the shift range is permitted during the switching restriction reaches a predetermined upper limit number. The range switching control device according to claim 2 or 3. The switching restriction means (41) terminates the switching restriction when a state in which the motor (12) is not energized during the switching restriction continues for a predetermined cooling time necessary for cooling the motor (12). The range switching control device according to any one of claims 1 to 4, wherein the range switching control device is provided. 6. The range switching control device according to claim 5, wherein the switching limiting means (41) extends the predetermined cooling time as the power supply voltage detected by the voltage detecting means (33) is lower. The range switching control device according to claim 5 or 6, wherein the switching limiting means (41) lengthens the predetermined cooling time as the current detected by the current detecting means (34) decreases.   The switching restriction means (41) makes the predetermined current value larger when the current shift range is the P range than when the current shift range is a range other than the P range. Item 8. The range switching control device according to any one of Items 1 to 7.

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