JP2008196614A - Range changeover control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely learn an L-range-side limit position (L-range wall position), in a motor-driven range changeover control system having a plurality of running ranges (a D range, an L range and the like). <P>SOLUTION: After starting a system (after power is turned on), an L-range wall hitting control is executed to learn the L-range wall position when a target range is changed over to one of running ranges such as a D range, 2 range and L range; a play amount of a rotation transmission system is learnt based on the learning value of a P-range wall position and a learning value of the L-range wall position; and the learning value thereof is stored in a back-up RAM. Thereafter, the shift range is changed over to an original target range. If a predetermined period (or a predetermined running number or a predetermined cumulative running distance) elapses from the previous learning of the L-range wall position, the L-range wall position is learnt by executing the L-range wall hitting control similar to the above and the play amount of the rotation transmission system is learnt, and the learning value thereof is stored in the back-up RAM to update it. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a range switching control device that switches a shift range of a range switching mechanism by driving a motor in accordance with a driver's range switching operation.

  In recent years, electronic control has progressed, and as shown in Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-136035), a driver's range switching operation (operation of a shift lever) is detected by a switch or the like, and the detection is performed. A so-called shift-by-wire range switching control system has been developed in which a motor is driven and controlled based on a signal to switch a shift range of a range switching mechanism to a target range.

  In this device, an output shaft is connected to a rotating shaft of a motor via a speed reduction mechanism, and a range switching mechanism is driven by the output shaft to switch the shift range of the automatic transmission. In this case, the motor is equipped with an encoder for detecting the rotational position, and when the range is switched, the motor is set to a target corresponding to the target range based on the count value of the output pulse of the encoder (hereinafter referred to as “encoder count value”). By rotating to the rotational position (target count value), the range switching mechanism is switched to the target range.

  By the way, the rotation amount (rotation angle) of the motor is converted into the operation amount of the range switching mechanism via a rotation transmission system such as a speed reduction mechanism, but there is play (backlash) between the components constituting the rotation transmission system. Exists. For example, there is play (backlash) between the gears of the speed reduction mechanism, and a non-circular cross-section (square, D cut shape, etc.) connecting portion formed at the tip of the rotation shaft of the speed reduction mechanism is used as a fitting hole of the output shaft In the configuration of fitting and connecting, a clearance for facilitating the fitting operation of both is required. As described above, since there is play in the rotation transmission system that converts the rotation amount (rotation angle) of the motor into the operation amount to be controlled, the rotation amount of the motor is accurately controlled based on the encoder count value. Even so, an error corresponding to the play (backlash) of the rotation transmission system occurs in the operation amount of the range switching mechanism, and the operation amount of the range switching mechanism cannot be accurately controlled.

Therefore, as shown in Patent Document 1, when the target range is the P range for the first time after starting the system, the motor is rotated until it reaches the limit position on the P range side of the movable range of the range switching mechanism. Executes contact control to learn the limit position on the P range side, and when the target range first becomes the D range, the motor is rotated until it hits the limit position on the D range side of the movable range of the range switching mechanism. The D range side abutting control is performed to learn the limit position on the D range side, and the movable range of the range switching mechanism is based on the learned value of the limit position on the P range side and the learned value of the limit position on the D range side The actual measured value is calculated, and the difference between the actual measured value and the design value of the movable range is learned as the play amount of the rotation transmission system, and then the target rotational position (target count value) corresponding to the target range is calculated. When constant, so that in consideration of the amount of play of the learning value of the rotation transmission system based on the learning value of the limit position of the P range side setting the target rotational position.
JP 2006-136035 A

  In recent years, vehicles equipped with automatic transmissions having an L range, 2 ranges, etc. in addition to the D range as the running range are increasing. In such a system having a plurality of travel ranges, the shift range adjacent to the limit position on the travel range side of the movable range of the range switching mechanism is not the D range but the L range. When the target range becomes the L range, the L range side limit control is performed by rotating the motor until it hits the limit position on the L range side of the movable range of the range switching mechanism, and the limit on the L range side is implemented. It is necessary to learn the position.

  However, the majority of drivers travel only in the D range and have little opportunity to travel in the L range, so there is almost no opportunity to learn the limit position on the L range side. For this reason, there is a problem that the range switching control must be performed without learning the limit position on the L range side, and the reliability of the motor-driven range switching control system is lowered.

  The present invention has been made in consideration of such circumstances. Accordingly, the object of the present invention is to provide a motor-driven range switching control system having a plurality of travel ranges (D range, L range, etc.). It is an object of the present invention to provide a range switching control device that can reliably learn a limit position and improve the reliability of a motor-driven range switching control system.

  In order to achieve the above-described object, the invention according to claim 1 is configured such that the motor is driven and controlled in accordance with the driver's range switching operation, and the range switching member is rotated within a predetermined movable range, whereby the shift range is increased. , The P range, the R range, the N range, the D range, and the driving range other than D, and the P range is adjacent to one limit position of the movable range of the range switching member, and the other limit position is A range switching mechanism adjacent to a traveling range other than D, a rotational position detecting means for detecting the rotational position of the motor, and abutting for rotating the motor until it hits at least one limit position of the movable range of the range switching member In a range switching control device comprising learning means for executing control and learning the limit position based on a detection value of the rotational position detection means, the learning hand Rotates the motor until it hits the limit position on the travel range side of the movable range of the range switching member when the target range set by the driver's range switching operation is the D range or a travel range other than D The shift range is switched to the original target range after learning the limit position on the travel range side by executing the butting control.

  In this configuration, when the driver switches from the P range to the D range to start the vehicle, the abutting control is performed to rotate the motor until it hits the limit position on the travel range side to learn the limit position on the travel range side. Therefore, even when the driver does not switch to a travel range other than D, the limit position on the travel range side can be surely learned when starting, and the reliability of the motor-driven range switching control system can be improved. Can be improved.

  In this case, since the time required for learning the limit position on the driving range side is short, the learning usually ends within a short time from when the driver switches from the P range to the D range and depresses the accelerator pedal to start the vehicle. Thus, even if the accelerator pedal is depressed before the end of learning, the driving range other than D also transmits the driving force in the forward direction to the driving wheels in the same manner as the D range. Since it is a range, it can start like the D range and does not impair the starting performance.

  In the present invention, for example, every time the driver switches to the D range, the limit position on the traveling range side may be learned, but the abutting control at the time of learning is a component of the rotation transmission system by the driving force of the motor. Is placed on the limit position (wall) of the movable range, a load is imposed on the parts of the rotation transmission system. For this reason, as the number of executions of the abutting control increases, the components of the rotation transmission system may be gradually deformed / damaged, resulting in a decrease in durability and reliability.

  As a countermeasure against this, as in claim 2, when the target range is the P range, the abutting control is performed to rotate the motor until it reaches the limit position on the P range side of the movable range of the range switching member, and the P range side Of the rotation range of the rotation transmission system by calculating the actual value of the movable range of the range switching member based on the learned value of the limit position on the P range side and the learned value of the limit position on the travel range side. The amount is learned (play amount = actual value of movable range−design value), and the learned value is stored in a storage means that can be stored and retained even when the power is turned off. When the value is stored, the limit position on the traveling range side may not be learned.

  In other words, the amount of play in the rotation transmission system changes little by little due to wear and deformation of the components of the rotation transmission system, but this change is a change that gradually appears over a long period of time. Therefore, there is no problem even if the amount of play in the rotation transmission system is treated as a constant value. Therefore, if the limit position on the P range side and the limit position on the traveling range side are learned, and the play amount of the rotation transmission system is learned and stored from those learned values, then the system is started (power supply) Only when learning the limit position on the P range side at the time of ON), and using the learned value of the play amount of the rotation transmission system based on the learned value of the limit position on the P range side, the motor target corresponding to the target range Since the rotational position can be set accurately, it is not necessary to learn the limit position on the traveling range side. Thereby, the number of executions of the abutting control can be greatly reduced, and the durability and reliability of the system can be improved.

  In this case, as in claim 3, when the target range becomes the D range or a travel range other than D every predetermined period, every predetermined number of travels or every predetermined total travel distance, the limit position on the travel range side is learned. May be performed. In this way, it is possible to periodically learn the deviation of the limit position (change in the play amount of the rotation transmission system over time) due to wear / deformation of the components of the rotation transmission system, and the control accuracy decreases over a long period of time. Can be prevented.

Hereinafter, an embodiment embodying the best mode for carrying out the present invention will be described.
First, the configuration of the range switching mechanism 11 will be described with reference to FIGS.

  The range switching mechanism 11 changes the shift range of the automatic transmission 12, for example, P range (parking range), R range (reverse range), N range (neutral range), D range (drive range), 2 range, L range. (Low range). The motor 13 serving as a drive source of the range switching mechanism 11 is constituted by a synchronous motor such as a switched reluctance motor (SR motor), for example, and includes a speed reduction mechanism 14 (see FIG. 2). An output shaft sensor 16 that detects the rotational position of the output shaft 15 that is fitted and connected to the output shaft 15 is provided. This output shaft sensor 16 is composed of a switch having six contacts that are turned on (ON) in a rotation angle range corresponding to each range of P, R, N, D, 2, and L, and any of the contacts is in an on state. The actual shift range is detected by determining whether or not.

  On the other hand, a detent lever 18 (range switching member) for switching the manual valve 17 of the hydraulic circuit of the automatic transmission 12 is fixed to the output shaft 15. An L-shaped parking rod 19 is fixed to the detent lever 18, and a cone 20 provided at the tip of the parking rod 19 is in contact with the lock lever 21. The lock lever 21 is moved up and down around the shaft 22 in accordance with the position of the cone 20 to lock / unlock the parking gear 23. The parking gear 23 is provided on the output shaft of the automatic transmission 12, and when the parking gear 23 is locked by the lock lever 21, the driving wheel of the vehicle is held in a stopped state (parking state).

  Further, the spool valve 24 of the manual valve 17 is connected to the detent lever 18, and the position of the spool valve 24 of the manual valve 17 is switched by rotating the detent lever 18 integrally with the output shaft 15 by the motor 13. The hydraulic clutch incorporated in the automatic transmission 12 is switched to any of the P range, R range, N range, D range, 2 range, and L range. In this case, the D range, the 2 range, and the L range are the travel ranges referred to in the claims.

  The detent lever 18 is formed with six holding recesses 25 (see FIG. 3) for holding the spool valve 24 at positions corresponding to the above ranges, and holds the detent lever 18 at positions corresponding to the respective ranges. A detent spring 26 is fixed to the manual valve 17. The engaging portion 27 provided at the tip of the detent spring 26 is fitted into the holding recess 25 of the target range of the detent lever 18, whereby the detent lever 15 is held at the rotational position of the target range, and the manual valve 17 The position of the spool valve 24 is held at the target range position. As shown in FIG. 3, the six holding recesses 25 of the detent lever 18 are arranged in the order of P range, R range, N range, D range, 2 range, and L range, and the detent lever 18 (engaging portion 27). ), The P range is adjacent to one limit position of the movable range, and the L range, which is a travel range other than D, is adjacent to the other limit position. A detent mechanism 28 is constituted by the detent lever 18, the detent spring 26, and the like.

  In the P range, the parking rod 19 moves in the direction approaching the lock lever 21, the thick part of the cone 20 pushes up the lock lever 21, and the convex portion 21 a of the lock lever 21 fits into the parking gear 23. The gear 23 is locked, whereby the output shaft (vehicle drive wheel) of the automatic transmission 12 is held in the locked state (parking state).

  In ranges other than the P range, the parking rod 19 moves away from the lock lever 21, the thick part of the cone 20 comes out of the lock lever 21, and the lock lever 21 descends. The portion 21a is disengaged from the parking gear 20, the parking gear 20 is unlocked, and the output shaft of the automatic transmission 12 is held in a rotatable state (running state).

  On the other hand, the motor 13 is provided with an encoder 31 for detecting the rotational position of the rotor. The encoder 31 is composed of, for example, a magnetic rotary encoder, and is configured to output A-phase, B-phase, and Z-phase pulse signals to the range switching control device 32 in synchronization with the rotation of the rotor of the motor 13. Has been. The range switching control ECU 33 (microcomputer) provided in the range switching control device 32 counts both rising and falling edges of the A-phase signal and B-phase signal output from the encoder 31, and the encoder The motor 13 is rotationally driven by switching the energized phase of the motor 13 in a predetermined order by the motor drive circuit 34 according to the count value.

  At this time, the rotation direction of the rotor is determined based on the generation order of the A-phase signal and the B-phase signal, the encoder count value is counted up in the forward rotation direction (P range → D range rotation direction), and the reverse rotation direction (D range) (→ P range rotation direction) The encoder count value is counted down. As a result, the correspondence relationship between the encoder count value and the rotational position of the motor 13 is maintained even if the motor 13 rotates in either the forward rotation / reverse rotation direction. However, the rotational position of the motor 13 can be detected by the encoder count value, and the motor 13 can be rotationally driven by energizing the winding of the phase corresponding to the rotational position. Note that the Z-phase signal of the encoder 31 is used to detect the reference rotational position of the rotor.

  In this embodiment, the output shaft sensor 16 is used as the shift range detecting means for detecting the actual shift range of the range switching mechanism 11. However, the output shaft sensor 16 is omitted, and the actual shift range is determined by the encoder count value. You may make it detect.

  When the driver operates the shift lever of the automatic transmission 12, the operation position (target range) of the shift lever is detected by the shift range detection device 36, and the output signal (target range signal) of the shift range detection device 28 is detected. It is input to the ECU 33 for range switching control. Accordingly, the range switching control ECU 33 sets a target rotation angle (target value of the encoder count value) corresponding to the target range, starts energization of the motor 13, and the encoder count value matches the target value. The motor 13 is feedback-controlled so as to stop at.

  By the way, the rotation amount (rotation angle) of the motor 13 is converted into an operation amount (sliding amount of the parking rod 19) of the range switching mechanism 11 through a rotation transmission system including the speed reduction mechanism 14, the output shaft 15, the detent lever 18, and the like. However, there is play between the parts constituting the rotation transmission system. For example, there is a backlash between the gears of the speed reduction mechanism 14, and in a configuration in which a connection portion having a non-circular cross section formed at the tip of the rotation shaft of the motor 13 is fitted into the fitting hole of the output shaft 15 and connected. A clearance is required to facilitate the fitting operation of both.

  Further, as shown in FIG. 3, when the engaging portion 27 of the detent spring 26 is fitted into the holding recesses 25 on the P range side and the L range side of the detent lever 18, the engaging portion 27 and the holding recesses are provided. There is a slight gap (backlash) between the 25 side walls. Thus, in the rotation transmission system that converts the rotation amount of the motor 13 into the operation amount of the range switching mechanism 11 (rotation angle of the detent lever 18), there is play (backlash) due to backlash, gaps between parts, and the like. Even if the rotation amount (rotation angle) of the motor 13 is accurately controlled based on the encoder count value, an error corresponding to the play (backlash) of the rotation transmission system occurs in the operation amount of the range switching mechanism 11, and the range The operation amount of the switching mechanism 11 cannot be accurately controlled.

  Therefore, in this embodiment, the range switching control ECU 33 has a function (learning means) for learning the play amount of the rotation transmission system. Specifically, when the target range is the P range when the system is started (when the power is turned on), the engaging portion 27 of the detent spring 26 is the limit position on the P range side of the movable range of the range switching mechanism 11. "P range wall abutting control" is performed to reversely rotate the motor 13 until it hits the side wall of the P range holding recess 25 (hereinafter referred to as "P range wall"), and the encoder count value Np (P range wall position) P range wall position learning value) is learned.

  Thereafter, when the driver operates the shift lever to switch the target range from the P range to the D range, the 2 range, or the L range, the L range side (travel range) of the movable range of the range switching mechanism 11 "L range wall abutting control" is performed in which the motor 13 is rotated forward until it hits the side wall of the L range holding recess 25 (hereinafter referred to as "L range wall"), which is the limit position on the side). The encoder count value Nl (L range wall position learning value) is learned.

After that, an increase / decrease amount (Nl−Np) of the encoder count value from the P range wall position to the L range wall position is obtained as an actual value of the movable range of the range switching mechanism 11, and then the actual value of the movable range and the movable value The difference from the design value of the range is learned as a play amount of the rotation transmission system, and the learned value of the play amount of the rotation transmission system is stored in the backup RAM 37 which is a storage means capable of storing and holding even when the power is turned off.
Play amount of rotation transmission system = Actual value of movable range-Design value

  Thereafter, when the motor 13 is rotated to the target position (target count value) corresponding to the target range, the target position is determined based on the learned value of the play amount of the rotation transmission system based on the P range wall position learned value Np. This is set in consideration of the rotation direction of the motor 13. In this way, even if there is play (backlash) in the rotation transmission system, the target position including the play (backlash) can be set, and the operation amount of the range switching mechanism 11 can be controlled with high accuracy. it can.

  As in this embodiment, in a system having a plurality of travel ranges (a system having an L range and the like in addition to the D range), the shift range adjacent to the limit position on the travel range side of the movable range of the range switching mechanism 11 is Since the L range is used instead of the D range, it is conceivable that when the target range is the L range, the L range wall abutting control is performed to learn the L range wall position. However, the majority of drivers travel only in the D range and have little opportunity to travel in the L range, so there is little opportunity to learn the L range wall position. For this reason, the range switching control must be performed without learning the L range wall position (learning the amount of play of the rotation transmission system), which reduces the reliability of the motor-driven range switching control system. There is a problem.

  As a countermeasure, in this embodiment, when the target range is switched from the P range to the D range, the 2 range, or the L range, after learning the L range wall position, the shift range is changed to the original target range. The range is switched.

  In this configuration, when the driver switches from the P range to the D range and starts the vehicle, the L range wall abutting control can be performed to learn the L range wall position. Even when switching is not performed, the L range wall position can be reliably learned at the time of start, and the reliability of the motor-driven range switching control system can be improved.

  In this case, since the time required for learning the L range wall position is short, the learning usually ends within a short time from when the driver switches from the P range to the D range and depresses the accelerator pedal to start the vehicle. Even if the accelerator pedal is depressed before the end of learning, the L range is a traveling range that transmits the driving force in the forward direction to the driving wheels in the same way as the D range. The vehicle can be started in the same manner as the D range, and the starting performance is not impaired.

  In the present invention, for example, the L range wall position may be learned every time the driver switches to the D range. The L range wall abutting control at the time of learning is performed by the rotation transmission system by the driving force of the motor 13. Since the part is put in a state of abutting against the L range wall, a burden is imposed on the part of the rotation transmission system. For this reason, as the number of executions of the L-range wall abutting control increases, the components of the rotation transmission system may be gradually deformed / damaged, resulting in a decrease in the durability and reliability of the system.

  As a countermeasure, in this embodiment, after learning the P range wall position and the L range wall position as a whole, the play amount of the rotation transmission system is learned based on the learned values of the P range wall position and the L range wall position. The learning value of the amount of play of the rotation transmission system is stored in a backup RAM 37 which is a storage means that can be stored and retained even when the power is turned off, and the learning value of the amount of play of the rotation transmission system is stored in the backup RAM 37. In this case, the learning of the L range wall position is not performed.

  In other words, the amount of play in the rotation transmission system changes little by little due to wear and deformation of the components of the rotation transmission system, but this change is a change that gradually appears over a long period of time. Therefore, there is no problem even if the amount of play in the rotation transmission system is treated as a constant value. Therefore, if the P range wall position and the L range wall position are learned and the play amount of the rotation transmission system is learned from the learned values and stored in the backup RAM 37, then the system is started up (when the power is turned on). ), The target rotational position of the motor 13 corresponding to the target range can be accurately determined using the learned value of the play amount of the rotation transmission system based on the learned value of the P range wall position. Since it can be set, it is not necessary to learn the L range wall position. As a result, the number of executions of the L range wall abutting control can be greatly reduced, and the durability and reliability of the system can be improved.

  Further, in this embodiment, the L range wall position is detected when the target range is any of the D range, the 2 range, and the L range every predetermined period, every predetermined number of times of travel, or every predetermined total travel distance. I try to learn. In this way, it is possible to periodically learn the change over time in the amount of play in the rotation transmission system due to wear and deformation of the components of the rotation transmission system, and to prevent a reduction in control accuracy over a long period of time. .

  The learning of the L range wall position according to the present embodiment described above is executed by the range switching control ECU 33 as follows according to the L range wall position learning program of FIG. The L range wall position learning program shown in FIG. 4 is activated when the system is activated (when the power is turned on), and serves as a learning means in the claims.

  When this program is started, first, in step 101, it is determined whether or not the L range wall position has been learned (whether or not the learning value of the play amount of the rotation transmission system is stored in the backup RAM 37). If the L range wall position has not yet been learned, the process proceeds to step 103 to determine whether or not the target range has been switched to one of the D range, the 2 range, and the L range. Wait until it is switched.

  After that, when the target range is switched to one of the driving ranges of D range, 2 range, and L range, the process proceeds to step 104, the L range wall abutting control is performed, and the L range wall position is learned. In step 105, the play amount of the rotation transmission system is learned based on the learned value of the P range wall position and the learned value of the L range wall position, and the learned value is stored in the backup RAM 37. Thereafter, the process proceeds to step 106, and the shift range is switched to the original target range.

  If it is determined in step 101 that the L range wall position has been learned (the learned value of the play amount of the rotation transmission system is stored in the backup RAM 37), the process proceeds to step 102, and the previous L range wall position is determined. It is determined whether or not a predetermined period (or a predetermined number of times of travel or a predetermined total travel distance) has elapsed since the time of learning, and a predetermined period (or a predetermined number of travels or a predetermined total travel distance) since the last learning of the L range wall position. If has not elapsed, the program is terminated as it is. On the other hand, if it is determined in step 102 that a predetermined period (or a predetermined number of times of travel or a predetermined total travel distance) has elapsed since the previous learning of the L range wall position, the processes of steps 103 to 106 described above are executed. When the target range is switched to either the D range, the 2 range or the L range, the L range wall abutting control is performed to learn the L range wall position and to increase the play amount of the rotation transmission system. After learning and updating and storing the learned value in the backup RAM 37, the shift range is switched to the original target range.

  In the present embodiment, two travel ranges, the 2 range and the L range, are provided as travel ranges other than the D range. However, only the L range may be provided. Of course, there are three travel ranges other than the D range. It may be above.

  In the present embodiment, the target range is instructed by the shift lever. However, the target range may be instructed by an operation member other than the shift lever.

  In addition, it goes without saying that the present invention can be implemented with various changes such as the configuration of the range switching mechanism 11 being appropriately changed.

It is a perspective view of the range switching apparatus in one Example of this invention. It is a figure which shows roughly the structure of the whole control system of one Example of this invention. It is a figure explaining the relationship between the holding | maintenance recessed part of the detent lever of one Example of this invention, and the engaging part of a detent spring. It is a flowchart which shows the flow of a process of the L range wall position learning program of one Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Range switching mechanism, 12 ... Automatic transmission, 13 ... Motor, 14 ... Deceleration mechanism, 15 ... Output shaft, 16 ... Output shaft sensor, 17 ... Manual valve, 18 ... Detent lever, 19 ... Parking rod, 21 ... Lock Lever, 23 ... parking gear, 24 ... spool valve, 25 ... holding recess, 26 ... detent spring, 27 ... engagement part, 28 ... detent mechanism, 31 ... encoder (rotation position detecting means), 32 ... range switching control device, 33... ECU (learning means) for range switching control, 36... Shift range detection device, 37... Backup RAM (storage means capable of storing and holding even when power is off)

Claims (3)

The shift range is set to a range other than the P range, R range, N range, D range, and D by driving the motor according to the range switching operation of the driver and rotating the range switching member within a predetermined movable range. A range switching mechanism in which a P range is adjacent to one limit position of the movable range of the range switching member and a travel range other than the D is adjacent to the other limit position;
Rotational position detecting means for detecting the rotational position of the motor;
Learning means for executing abutting control for rotating the motor until it hits at least one limit position of the movable range of the range switching member and learning the limit position based on a detection value of the rotation position detecting means; In the range switching control device,
The learning means until the target range set by the driver's range switching operation reaches the limit position on the traveling range side of the movable range of the range switching member when the target range is a D range or a traveling range other than D. A range switching control device characterized by switching the shift range to an original target range after performing abutting control for rotating the motor and learning a limit position on the traveling range side. The learning means executes abutting control to rotate the motor until it reaches the limit position on the P range side of the movable range of the range switching member when the target range is the P range, and sets the limit position on the P range side. Learning, calculating an actual measurement value of the movable range of the range switching member based on the learned value of the limit position on the P range side and the learned value of the limit position on the traveling range side, thereby calculating the play amount of the rotation transmission system Learning and storing the learned value in a storage means that can store and hold even when the power is turned off,
2. The learning device according to claim 1, wherein the learning unit does not learn the limit position on the traveling range side when a learning value of the play amount of the rotation transmission system is stored in the storage unit. Range switching control device.   The learning means learns the limit position on the travel range side when the target range becomes the D range or a travel range other than the D every predetermined period, every predetermined number of travels or every predetermined total travel distance. The range switching control device according to claim 2.

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