Control device for range switching mechanism

Abstract

Control device, with a range switching mechanism (11) in a vehicle, the range switching mechanism (11) being configured to change a switching range using a motor (13) as a drive source, a range shift operating device (28) through which an occupant of the vehicle inputs a requested shift range requested by the occupant, wherein the engine is controlled according to the requested shift range input by the range shift operating device (28) such that the shift range of the range shift mechanism (11) is changed to the requested shift range, an actuation frequency monitoring device (33, 101 to 106, 101a, 102a) which is designed to monitor an actuation frequency of the range switching actuation device (28), and a heat generation limiting control device (33, 107, 109, 202, 302, 411, 412, 502, 602) which is designed to switch a control of the engine (13) into a heat generation limiting control in which a heat generation rate is lower than that of a normal control when the actuation frequency of the range switching actuation device (28) exceeds a predetermined frequency, wherein the operation frequency monitoring means (33, 101, 101a, 102a) determines the operation frequency based on an operation number of times of performing the range switching operation and a rotation angle of the motor (13) for each range switching operation, and the operation frequency monitoring device (33, 101, 101a, 102a) comprises a consecutive operation number counter configured to increment a count value (CR) by a count-up value (ΔCR) based on the rotation angle of the motor (13) for each range switching operation, wherein the count value (CR) of the consecutive operation number counter is reset when a non-operation time exceeds a predetermined time, wherein the count value (CR) of the consecutive operation number counter is set as detected information of the operation frequency of the range switching operating device (28).

Description

[0001] The invention relates to a control device for controlling a range switching mechanism for changing (switching) a switching range of the range switching mechanism by driving and controlling a motor according to a range switching operation by a vehicle occupant.

[0002] In recent years, as described in JP 2002-286128 A and JP 2004-23932 A, a vehicle has been developed which is electronically controlled, and a system has been developed for detecting, with a switch, a range shift operation (gear shift operation) by an occupant, and for driving and controlling a motor based on the detection signal to change the shift range of a range shift mechanism to a requested shift range requested by the occupant. JP 2004-23932 A also shows the Fig. 1 to 4 of the present application.

[0003] As in Fig. As shown in Figure 5, each time the range shift operation is performed to change the shift range to the requested shift range, the motor is started accordingly, and it is stopped after the shift range of the range shift mechanism is changed to the requested shift range, and the start and stop are repeated. While the motor is energized, a coil of the motor and a drive circuit generate heat. Therefore, the heat generated by energizing the motor while the motor is stopped is released so that a temperature of the motor is reduced (for example, an engine stop period in which the motor is stopped serves as a motor cooling period).

[0004] Generally, while the vehicle is traveling, the passenger cannot frequently change the shift range from one travel range (e.g., D range) to another. However, when the vehicle is stopped, the passenger may frequently perform useless range shift operations for entertainment (e.g., for fun) because the shift range can be changed to any range when the vehicle is stationary. In a case where the range shift operation is frequently repeated, the engine stop time (engine cooling time) for each range shift operation may be shortened or become zero. As a result, an increase in temperature due to heat generation by the motor coil and the drive circuit may not be limited, and the motor coil and the drive circuit may have an excessively high temperature. This may reduce the service life of the system and cause a failure.cause the system to malfunction.

[0005] Document DE 10 2005 017 630 A1 discloses a system and method for determining the running status of a motor by counting the number of start-up and stop-up cycles. The supply switch is turned off if the number of starts during a selected interval exceeds a certain limit.

[0006] Document DE 100 56 284 A1 discloses a method for determining the load condition of an electric motor drive of an actuating device. The temperature of the drive motor is monitored, and operation is prevented if a certain temperature is exceeded.

[0007] It is an object of the present invention to provide a control device for controlling an electric motor for switching a shift range of a range switching mechanism, in order to limit an increase in temperature due to heat generation of a coil of the electric motor and a drive circuit when an occupant repeatedly performs a useless range switching operation for amusement while the vehicle is stopped or stationary.

[0008] This object is achieved by a control device as defined in claim 1 and alternatively by a control device as defined in claim 7.

[0009] Advantageous embodiments are specified in the dependent patent claims.

[0010] The invention is described in more detail below with reference to the accompanying drawings. They show: Fig. 1 is a perspective view of a range switching device; Fig. 2 is a schematic diagram showing a general configuration of a control system of the range switching device; Fig. 3 is a view used to explain a configuration of an engine; Fig. 4 is a view used to explain a circuit configuration for controlling or driving the motor; Fig. 5 is a timing chart for explaining a relationship between a range switching operation and an energization period for energizing a motor; Fig. 6 is a flowchart showing a flow of a process of a range switching operation frequency monitoring routine of the first embodiment; Fig. 7 is a timing chart showing a control example of the first embodiment; Fig. 8 is a flowchart showing a flow of a process of a normal control routine of a second embodiment of the present invention; Fig. 9 is a flowchart showing a flow of a process of a heat generation limiting control routine of the second embodiment of the present invention; Fig. 10 is a schematic diagram showing a general configuration of a control system of a range switching device of a third embodiment of the present invention; Fig. 11 is a flowchart showing a flow of a process of a normal control routine of the third embodiment; Fig. 12 is a flowchart showing a flow of a process of a heat generation limiting control routine of the third embodiment; Fig. 13 is a flowchart showing a flow of a process of a normal control routine of a fourth embodiment of the present invention; Fig. 14 is a flowchart showing a flow of a process of a heat generation limiting control routine of the fourth embodiment; Fig. 15 is a flowchart showing a flow of a process of a normal control routine of a fifth embodiment of the present invention; Fig. 16 is a flowchart showing a flow of a process of a heat generation limiting control routine of the fifth embodiment; Fig. 17 is a flowchart showing a flow of a process of a normal control routine of a sixth embodiment of the present invention; Fig. 18 is a flowchart showing a flow of a process of a heat generation limiting control routine of the sixth embodiment; and Fig. 19 is a flowchart showing a flow of a process of a range switching operation frequency monitoring routine of a seventh embodiment.

[0011] First to seventh embodiments will be described, which illustrate the best modes for carrying out the invention. <Erstes Ausführungsbeispiel>

[0012] The first embodiment will be described with reference to Fig. 1 to Fig. 7. The Fig. 1 to Fig. The arrangements shown in 4 are known from JP 2004-23 932 A.

[0013] First, referring to Fig. 1 and Fig. 2, a configuration of a range shift mechanism 11 is described. The range shift mechanism 11 changes (switches) a range of an automatic transmission 12 into, for example, a parking range (P), a reverse range (R), a neutral range (N), and a drive range (D). The range shift mechanism 11 has a motor 13 as a drive source, which includes, for example, a synchronous motor such as a switched reluctance (SR) motor. The motor 13 internally includes a reduction mechanism 14 (see FIG. Fig. 2), and it includes an output shaft sensor 16 for detecting a rotation angle of an output shaft 15 fitted and connected to a rotating shaft of the reduction mechanism 14. The output shaft sensor 16 includes a rotation angle sensor (e.g., a potentiometer) that linearly changes an output voltage according to the rotation angle of the output shaft 15 of the reduction mechanism 14 of the motor 13. Based on the output voltage, a current rotation angle of the output shaft 15 is detected, and a current shift range is selectively known from among P range, R range, N range, and D range.

[0014] The output shaft 15 of the engine 13 includes a lock lever 18 fixed thereto for switching a manual valve 17 for oil hydraulic shifting of the automatic transmission 12. The lock lever 18 is fixed to an L-shaped parking rod 19, and the parking rod 19 has a tapered body 20 at one end portion of the rod 19 such that the tapered body 20 contacts a lock lever 21. The lock lever 21 moves up and down around a shaft 22 according to a position of the tapered body 20 to lock and unlock a parking gear 23. The parking gear 23 is provided to an output shaft of the automatic transmission 12, and when the parking gear 23 is locked by the lock lever 21, rotation of a drive wheel of the vehicle is restricted (maintained in a parking state).

[0015] The lock lever 18 is also connected to a spool valve 24 of the manual valve 17, and the motor 13 rotates the lock lever 18 together with the output shaft 15 to change an operation amount of the manual valve 17 (for example, change a position of the spool valve 24) so ​​as to change the range of the automatic transmission 12 to any of the P range, R range, N range, and D range. The lock lever 18 is provided with four support recesses 25 configured to hold the spool valve 24 at positions corresponding to the foregoing shift ranges.

[0016] In contrast, the manual valve 17 is fixed with a detent spring 26 that supports the detent lever 18 at a position corresponding to each of the shift ranges. Therefore, when an engaging portion 27 provided at one end of the detent spring 26 is fitted to the support recess 25 of the detent lever 18 corresponding to a requested shift range, the detent lever 18 is held at a rotation angle of the requested shift range. As a result, a location of the spool valve 24 of the manual valve 17 is maintained at a position corresponding to the requested shift range.

[0017] For the P range, the parking rod 19 is displaced toward the lock lever 21 such that a thick portion of the tapered body 20 pushes the lock lever 21 upward. Therefore, a projection 21a of the lock lever 21 is fitted to the parking gear 23 such that the parking gear 23 is locked. As a result, the output shaft (drive gear) of the automatic transmission 12 is kept locked (maintained in the parking state).

[0018] In contrast, for the shift ranges other than the P range, the parking rod 19 is displaced from the lock lever 21 such that the thick portion of the conical body 29 is detached (disassembled) from the lock lever 21, and thereby the lock lever 21 descends (for example, it moves in Fig. 1 downward). As a result, the projection 21a of the lock lever 21 is disengaged from the parking gear 23 such that the parking gear 23 is unlocked. Thus, the output shaft of the automatic transmission 12 is rotatably maintained (maintained in a drive state).

[0019] Next, with reference to Fig. 3 and Fig. 4 describes a configuration of the motor 13. The motor 13 of the first embodiment is a switched reluctance motor in which both a stator core 36 and a rotor 37 have pronounced pole edge structures. This advantageously eliminates the need for a permanent magnet for the motor, and it therefore has a simple structure.

[0020] The stator core 36 has a hollow cylindrical shape and has an inner peripheral portion on which, for example, twelve salient poles 36a are arranged at equal intervals. Correspondingly, the rotor 37 has an outer peripheral portion on which, for example, eight salient poles 37a are arranged at equal intervals. Therefore, with one rotation of the rotor 37, each of the eight salient poles 37a of the rotor 37 alternately faces each of the salient poles 36a of the stator core 36 with a very small gap therebetween. The twelve salient poles 36a of the stator core 36 are wound with windings, and one winding for one of the two lines (a-line, b-line) for U-phase, V-phase, and W-phase of drive coils 38, 39 is wound at an opposite position to the other winding of the other line of the lines.Here, the number of salient poles 36a, 37a of the stator core 36 and the rotor 37 can be alternatively changed as required.

[0021] In the following description, the "U-phase", "V-phase", and "W-phase" of one line (a-line) of the lines of the drive coil 38 are respectively indicated as "Ua-phase", "Va-phase", and "Wa-phase". Furthermore, the "U-phase", "V-phase", and "W-phase" of the other line (b-line) of the lines of the drive coil 39 are respectively indicated as "Ub-phase", "Vb-phase", and "Wb-phase".

[0022] The winding of each phase of the drive coils 38, 39 of two lines is wound on each of the twelve salient poles 36a of the stator core 36 in this order, for example, Va phase → Wa phase → Ua phase → Va phase → Wa phase → Ua phase → Vb phase → Wb phase → Ub phase → Vb phase → Wb phase → Ub phase.

[0023] As in Fig. As shown in Figure 4, the drive coils 38, 39 are driven by two wires through each of the motor drive circuits 34, 35 using a battery 40 mounted on the vehicle as a power source. In this way, two wires of the drive coils 38, 39 and two wires of the motor drive circuits 34, 35 are provided such that even in a case where one of the two wires malfunctions, the other wire of the wires is configured to drive the motor 13. Fig. The circuit configuration of the motor drive circuits 34, 35 shown in FIG. 4 indicates a unipolar drive type circuit configuration in which one switching element 41, such as a transistor, is provided in each phase. Alternatively, a bipolar drive circuit configuration may be adopted in which two switching elements are provided in each phase.

[0024] An ECU 33 controls ON / OFF of each of the motor drive circuits 34, 35 and each of the switching elements 41. As shown in Fig. As shown in FIG. 2, the ECU 33 and each of the motor drive circuits 34, 35 are provided for a range shift control device 32. The range shift control device 32 is connected to a shift range detection device 28 that detects an operating position (requested shift range) of a shift lever operated by a passenger (driver of the vehicle). The shift lever and the shift range detection device 28 function as a range shift operating device of the present embodiment of the invention.

[0025] Furthermore, the motor 13 is equipped with an encoder 31 for detecting a rotation angle of the rotor 37. The encoder 31 includes, for example, a magnetic rotary encoder and is configured to be synchronized with a rotation of the rotor 37 of the motor 13 to output A-phase, B-phase, and Z-phase pulse signals to the range switching control device 32. The ECU 33 of the range switching control device 32 counts both the rising and falling edges of the A-phase signal and the B-phase signal output by the encoder 31. Then, the ECU 33 changes energization phases of the motor 13 using the motor drive circuits 34, 35 to rotate and drive the motor 13 in a predetermined order (sequence) according to the encoder count value (the counted number of edges of signals output from the encoder 31).

[0026] In this case, a rotation direction of the rotor 37 is determined based on a generation sequence of the A-phase signal and the B-phase signal. For normal rotation (a direction from P range → D range), the encoder count is incremented (e.g., counted up). Furthermore, for reverse rotation (a direction from D range → P range), the encoder count is decremented (e.g., counted down). In this way, even when the motor 13 rotates in either direction (normal direction / reverse direction), a corresponding relationship can be maintained between the encoder count and the rotation angle of the motor 13, and therefore, the rotation angle of the motor 13 can be detected based on the encoder count in either direction of rotation (e.g., normal rotation / reverse rotation). Consequently, the winding of the phase corresponding to the rotation angle is energized.supplied with power to rotate and drive the motor 13. Note that a Z-phase signal from the encoder 31 is used to detect a reference rotation angle of the rotor 37 of the motor 13.

[0027] When the passenger operates the shift lever of the automatic transmission 12, an operation position of the shift lever (requested shift range) is detected by the shift range detecting device 28, and an output signal of the shift range detecting device 28 (a signal of the requested shift range) is received by the ECU 33 of the range shift control device 32. Therefore, the ECU 33 sets a target rotation angle corresponding to the requested shift range (for example, it sets a target value for the encoder count) and starts energizing the motor 13. Then, the ECU 33 controls the motor 13 using feedback control such that the motor 13 stops at a position where the encoder count is equal to a target value. Normal feedback control is performed.automatic control is carried out by a normal drive (two-wire power supply), in which the drive coils 38, 39 are energized or supplied with energy by two lines (two drive coils 38, 39) in order to rotate and drive the rotor 37.

[0028] In the first embodiment, normal driving (two-wire energization 2) is performed by a 1-2-phase excitation method in which single-phase energization and two-phase energization are alternately switched, although a 1-phase excitation method in which only single-phase energization is applied or a 2-phase excitation method in which only two-phase energization is applied may be used. In either excitation method, for normal driving (two-wire energization 2), the Ua phase and the Ub phase are simultaneously energized to energize the "U phase," and the Va phase and the Vb phase are simultaneously energized to energize the "V phase." In addition, the Wa phase and the Wb phase are simultaneously energized to energize the "W phase."

[0029] As in Fig. As shown in Fig. 5, each time the range shift operation is performed to change the requested shift range, the motor 13 is started, and then the motor 13 is stopped after the shift range of the range shift mechanism 11 is changed to the requested shift range by feedback control, and the start and stop are repeated. While the motor 13 is energized, the drive coils 38, 39 of the motor 13 and the drive circuits 34, 35 generate heat. The motor stop period also serves as the motor cooling period, during which the heat generated by energizing the motor 13 is released to reduce the temperature.

[0030] While the vehicle is being driven (running), the occupant cannot frequently change the shift range from the D range to another range. However, since the shift range can be changed to any range while the vehicle is stopped, the occupant may frequently repeat useless range shift operations for entertainment while the vehicle is stopped. In a case where the range shift operation is frequently performed, the engine stop time (engine cooling time) for each range shift operation may be shortened or become zero. As a result, the increase in temperature due to heat generation by the drive coils 38, 39 of the motor 13 and the drive circuits 34, 35 cannot be controlled. Therefore, this may result in an excessive increase in the temperature of the drive coils 38, 39 of the motor 13 and the drive circuits 38, 39.In this way, it may shorten the lifespan of the system and cause a failure or malfunction of the conventional state-of-the-art system.

[0031] In contrast, the ECU 33 of the range shift control device 32 in the first embodiment implements, as the countermeasure to the foregoing drawbacks of the prior art, a (later described with reference to Fig. 6) to monitor an operation frequency of the range shift operation. Furthermore, in this routine, when the operation frequency of the range shift operation exceeds a predetermined frequency, it is determined that the increase in temperature due to heat generation by the motor 13 may exceed an allowable level if the range shift operation is repeated more frequently than this condition. In this manner, until a predetermined motor cooling period elapses, control of the motor 13 is changed to heat generation limiting control in which heat generation is less than that for normal control in a normal state, and further, a warning display is displayed in a warning display element 29 (warning means) to stop the useless range shift operation. Here, the warning display element 29 is mounted on an instrument panel.Mounted on the dashboard near a driver's seat. Alternatively, a warning tone can be generated. Alternatively, a similar warning can be generated via a synthetic speech.

[0032] The present first embodiment considers the increase in temperature of the drive coils 38, 39 of the motor 13 and the drive circuits 34, 35 in a case where the range switching operation is frequently repeated. Typically, the temperature of the drive coils 38, 39 of the motor 13 and the drive circuits 34, 35 increases in proportion to the number of times the range switching operation is repeated due to the accumulation of heat generation of the drive coils 38, 39 and the drive circuits 34, 35. Here, the number of times the range switching operation is repeated consecutively with a short operation interval is counted, and the count value is used as detection information of the operation frequency of the range switching operation.Typically, the operation interval is equal to or less than a predetermined time (for example, the operation interval so small that the motor cooling time required to limit the temperature increase is not reached). Therefore, the detection information of the operation frequency of the range switching operation serves as information corresponding to the temperature increase due to heat generation by the drive coils 38, 39 of the motor 13 and the drive circuits 34, 35. As a result, when the range switching operation is frequently repeated, the control is changed to the heat limit control at an appropriate timing according to the temperature increase of the drive coils 38, 39 of the motor 13 and the drive circuits 34, 35.

[0033] In addition, if the range shift operation is frequently repeated, this may be caused by the frequent repetition of the useless range shift operation by the occupant for amusement while the vehicle is stopped. Therefore, in the first embodiment, the heat generation limiting control is performed such that the energization to the motor 13 is temporarily prohibited (for example, the heat generation limiting control serves as a control for temporarily prohibiting the change of the shift range). In this way, the increase in temperature due to heat generation by the drive coils 38, 39 of the motor 13 and the drive circuits 34, 35 can be more effectively limited (controlled). Since the range shift operation of this case is the useless range shift operation, temporarily prohibiting the change of the shift range does not deteriorate the drivability of the vehicle.

[0034] In the above-described change of the engine control according to the operation frequency of the range shift operation, the ECU 33 of the range shift control device 32 executes the Fig. 6 is executed as follows.

[0035] The Fig. The range shift operation frequency monitoring routine shown in FIG. 6 is executed by a predetermined cycle while the ECU 33 is turned on. When the present routine of the present time is started, it is first determined at step 101 whether the range shift operation has been performed since (after) the present routine of the previous time was executed. If the range shift operation has been performed, control proceeds to step 102 to increment a count value CR of an operation number counter (consecutive operation number counter) by one, which counts an operation number of times the range shift operation is performed, and at step 103, a count value CT of an operation interval counter, which counts a time elapsed since a time of the range shift operation of the previous time, is reset to zero.

[0036] In contrast, if it is determined at step 101 that the range shift operation has not been performed, control proceeds to step 104, where the count value CT counted by the operation interval counter is incremented by one to count the time elapsed since the time of performing the range shift operation of the previous time. Thereafter, at step 105, it is determined whether the count value CT of the operation interval counter (e.g., the elapsed time since the time of the range shift operation of the previous time) is equal to or greater than a predetermined value KT (e.g., a predetermined time KT). Here, the predetermined value KT is set as a value corresponding to a time required for cooling the engine 13 while the engine 13 is stopped by releasing heat generation due to energization of the engine 13 at the previous time.The predetermined value KT may be a predetermined constant value, although the predetermined value KT may alternatively be designed to increase in accordance with the increase in the count value CR of the operation number counter in consideration of the increase in the temperature of the motor 13 due to the accumulation of the heat generated by the motor 13 as the number of repetitions of the range switching operation increases.

[0037] If it is determined at step 105 that the count value CT of the range interval counter (the elapsed time since the time of the range switching operation of the previous time) is equal to or greater than the predetermined value KT, it is determined that the heat generated due to the energization of the engine 13 at the previous time is substantially released during the stop of the engine 13. Consequently, the count value CR counted by the operation number counter is reset to zero at step 106. In contrast, if it is determined at step 105 that the count value CT of the operation interval counter is less than the predetermined value KT, the count value CR of the operation number counter is not reset.In this way, when a non-operation time in which no range switching operation is performed exceeds (e.g., is equal to or greater than) the predetermined time (KT), the count value CR counted by the operation number counter is reset to zero.

[0038] By repeating the processes described in steps 101 to 106 through the predetermined cycle, the operation number counter counts the number of consecutive (continuous) operations of the range shift operation performed consecutively with the short operation interval. Typically, the short operation interval is equal to or less than the predetermined time KT (that is, the short operation interval is less than the engine cooling period required to limit the increase in temperature). The count value CR (the number of times of consecutive operations) is used as the detection information of the operation frequency of the range shift operation. The foregoing processes in steps 101 to 106 serve as an operation frequency monitor of the present invention.In this way, with a very simple process using a consecutive operation counter, the detection information of the operation frequency of the range switching actuator can serve as information consistent with the temperature increase due to heat generation of the coils of the motor and the drive circuit. As a result, when the range switching operation is frequently repeated, control can be changed to heat generation limiting control at an appropriate timing corresponding to the temperature increase of the coils of the motor and the drive circuit.

[0039] Next, at step 107, it is determined whether the count value CR of the operation number counter (the number of times of consecutive operation of the range shift operation with the short operation interval equal to or less than the predetermined time KT) is equal to or greater than a predetermined value KR. Typically, the predetermined value KR is set to correspond to an operation number of times, indicating that the temperature increase due to heat generation by the motor 13 may exceed an allowable level if the range shift operation is repeated more than this operation number of times.

[0040] If it is determined at step 107 that the count value CR of the operation number counter is smaller than the predetermined value KR (that is, the operation frequency of the range shift operation is lower than the predetermined frequency), it is determined that the temperature increase due to heat generation by the motor 13 has not exceeded the allowable level, and control proceeds to step 108 to execute normal control. In normal control, for example, the range shift operation is performed, and each time the required shift range is changed, the motor 13 is started, and then stopped after the shift range of the range shift mechanism 11 is changed to the requested shift range by feedback control.

[0041] In contrast, if it is determined at step 107 that the count value CR of the operation number counter is equal to or greater than the predetermined value KR, it is determined that the temperature increase due to heat generation by the motor 13 may exceed the allowable level in a case where the range shift operation is repeated more frequently than this condition. Therefore, at step 109, the control of the motor 13 is changed to the heat generation limiting control (for example, the control for temporarily prohibiting the energization of the motor 13 in the first embodiment) in which the heat generation is less than in the normal control, and the warning indication is shown in the warning display element 29 to limit the useless range shift operation (alternatively, the synthesized voice may be generated to issue the same warning).The processes at the foregoing steps 107 → 109 serve as heat generation limiting control means of the present invention.

[0042] Note that the following alternative process may be employed. After the control of the engine 13 is changed to the heat generation limiting control, it may additionally be determined whether a predetermined engine cooling period required to properly reduce the temperature of the engine 13 has elapsed since the count value CR of the operation number counter exceeds the predetermined value KR (for example, since the start of the heat generation limiting control). If it is determined that the predetermined engine cooling period has elapsed, the heat generation limiting control is terminated. In other words, the heat generation limiting control is executed for the predetermined engine cooling period since the time since the count value CR of the operation number counter exceeds the predetermined value KR.In addition, at the time point at which the predetermined motor cooling time period has elapsed, the count value of the operation number counter is reset to zero, so that the control returns to the normal control.

[0043] Now a tax example of the Fig. 6 range shift operation frequency monitoring routine with reference to a Fig. 7 is described. Each time the range switching operation is performed to change the requested shift range, the operation interval counter is reset and restarted to count the operation interval of the range switching operation. In addition, the count value CR of the operation number counter is incremented by one to count the operation number of times the range switching operation is performed. In this case, if the count value CT of the operation interval counter is less than the predetermined value KT, the count value CR of the operation number counter is not reset. However, at a time point t1 at which the count value CT of the operation interval counter reaches the predetermined value KT, the count value CR of the operation number counter is reset to zero.Thus, the operation counter counts the number of consecutive operations of the range shift operation performed consecutively or sequentially with the short operation interval. Typically, the operation interval is equal to or less than the predetermined value KT (that is, the short operation interval is less than the engine cooling time required to limit the temperature increase).

[0044] When the count value CR of the operation number counter is less than the predetermined value KR (that is, the operation frequency of the range switching operation is less than a predetermined frequency), normal control is performed. Furthermore, at a time t2 at which the count value CR of the operation number counter reaches the predetermined value KR, it is determined that the temperature increase due to heat generation by the motor 13 may exceed the allowable level if the range switching operation is repeated more frequently than this condition. Consequently, control is changed from normal control to heat generation limiting control (the control for temporarily prohibiting energization of the motor 13 in the first embodiment).

[0045] As a result, the temperature increase can be limited even if the occupant repeats the useless range shift operation for entertainment. Therefore, the reduction in the service life of the system due to excessive temperature increase is limited, and the malfunction due to excessive temperature increase is also limited.

[0046] In addition, in the first embodiment, since the warning display element 29 is configured to display the warning display to prevent the useless range switching operation (alternatively, the synthesized voice may be generated for the same warning) while the heat generation control is being executed, the occupant is prevented from performing the useless range switching operation.

[0047] Note that in the first embodiment, the heat generation limiting control is control for temporarily prohibiting energization of the motor 13 (control for temporarily prohibiting the change of the shift range), although in another example of the present invention, heat generation limiting control may be control for energizing the motor 13 with a smaller electric current than the normal control in the normal state. From here on, second to sixth embodiments will be described, which implement the foregoing example of the present invention. Each of the second to sixth embodiments is the same as the first embodiment except where clearly stated otherwise. (Second embodiment)

[0048] In the Fig. 8 and Fig. In the second embodiment of the present invention shown in FIG. 9, an energizing current of the motor 13 (motor drive voltage) is controlled by duty control. Furthermore, in a method similar to the first embodiment, the number of consecutive operations of the range switching operation, which is consecutively operated with the short operation interval, is counted by the operation number counter. Typically, the short operation interval is equal to or less than the predetermined time KT (for example, the operation interval is so short that the motor cooling time required to limit the temperature increase is not reached).When the count value CR of the operation number counter is less than the predetermined value KR (that is, the operation frequency of the range switching operation is less than a predetermined frequency), it is determined that the increase in temperature due to heat generation by the motor 13 has not exceeded the allowable level (allowable limit). Consequently, a warning signal shown in . Fig. 8 is executed such that an energization duty ratio of the motor 13 is set as a normal duty ratio, for example, 100% at step 201. Then, the motor 13 is driven according to the range switching operation with the duty ratio of 100% such that the shift range of the range switching mechanism 11 is changed to the requested shift range by feedback control.

[0049] Even if the count value CR of the operation number counter becomes equal to or greater than the predetermined value KR, it is determined that the temperature increase due to heat generation by the motor 13 may exceed the allowable level if the range switching operation is repeated more frequently than this condition. Consequently, a Fig. 9 is executed such that the energization duty ratio of the motor 13 is set as a lower duty ratio than usual, for example, 50% at step 202. Then, the motor 13 is driven according to the range switching operation with the duty ratio of 50%, which is lower than that of the normal control, such that the switching range of the range switching mechanism 11 is changed to the requested switching range by the feedback control.

[0050] As described in the second embodiment, when the energization duty cycle of the motor 13 is reduced while the heat generation limiting control is being executed, the drive voltage of the motor 13 is reduced so that the energization current of the motor 13 can be reduced. As a result, the temperature increase due to heat generation by the motor 13 can be limited.

[0051] It should be noted that the energization duty cycle for heat generation limitation control is not limited to 50%, and the energization duty cycle for normal control is not limited to 100%. The energization ratios can be modified as needed. (Third embodiment)

[0052] In the Fig. 10 to Fig. In the third embodiment of the present invention shown in FIG. 12, the motor drive circuits 34, 35 are equipped with electric current limiting circuits 42, 43 that set the energizing current of the motor 13 equal to or less than a preset upper current limit. The preset upper current limit values ​​of the electric current limiting circuits 42, 43 can be modified by the ECU 33 of the range shift control device 32.

[0053] In a method similar to the first embodiment, the operation number counter selects the number of times of consecutive operation of the range switching operation, which is consecutively performed with the short operation interval equal to or less than the predetermined time KT. If the count value CR of the operation number counter is less than the predetermined value KR, it is determined that the increase in temperature due to heat generation by the motor 13 has not exceeded the allowable level. Consequently, a Fig. 11 is executed such that the previously set upper limit values ​​of the electric currents of the electric current limiting circuits 42, 43 are set as normal set values, for example, 50A at step 301. As a result, the motor 13 is driven with the electric current of 50A according to the range switching operation such that the switching range of the range switching mechanism 11 is changed to the requested switching range by the feedback control.

[0054] If the count value CR of the operation number counter is equal to or greater than the predetermined value KR, it is determined that the temperature increase due to heat generation by the motor 13 may exceed the allowable level if the range switching operation is repeated more frequently than this condition. Consequently, a Fig. 12 is executed such that the preset upper limit values ​​of the electric currents of the electric current limiting circuits 42, 43 are set as lower electric current values ​​smaller than those for the normal control, for example, 10A at step 302. As a result, the motor 13 is driven according to the range switching operation with the lower electric current of 10A such that the switching range of the range switching mechanism 11 is changed to the requested switching range by the feedback control.

[0055] As described in the third embodiment, when the preset upper limit values ​​of the electric currents of the electric current limiting circuits 42, 43 are reduced while the heat generation limiting control is being executed, the energizing current of the motor 13 can be reduced so that the increase in temperature due to heat generation by the motor 13 can be limited.

[0056] It should be noted that the preset upper limit values ​​of the electric currents of the electric current limiting circuits 42, 43 are not limited to 10 A during the heat generation limiting control, and the preset upper limit values ​​of the electric currents of the electric current limiting circuits 42, 43 are not limited to 50 A during the normal control. The preset upper limit values ​​of the electric currents can be modified as required. (Fourth embodiment)

[0057] In the Fig. 13 and Fig. In the fourth embodiment of the present invention shown in FIG. 14, a motor drive method (motor control mode) is changed between one for normal control and the other for heat limit control. As a result, while heat limit control is being executed, the energizing current of the motor 13 can be reduced.

[0058] Specifically, in the method in the fourth embodiment, similar to the first embodiment, the operation number counter counts the number of times of consecutive operation of the range shift operation, which is consecutively operated with the short operation interval equal to or less than the predetermined time KT. When the count value CR of the operation number counter is less than the predetermined value KR, it is determined that the increase in temperature due to heat generation by the motor 13 has not exceeded the allowable level. Consequently, a Fig. 13 is executed such that the energization duty cycle of the motor 13 is set to a normal duty cycle, for example, 100% at step 401, and then the motor drive method is set to the feedback control at step 402. Consequently, the motor 13 is driven according to the range shift operation with the duty cycle of 100% by the feedback control, so that the shift range of the range shift mechanism 11 is changed to the requested shift range.

[0059] When the count value CR of the operation number counter becomes equal to or greater than the predetermined value KR, it is determined that the temperature increase due to heat generation by the motor 13 may exceed the allowable level if the range switching operation is repeated more frequently than this condition. Consequently, a Fig. 14 is executed such that the energization duty cycle of the motor 13 is set to a lower duty cycle than that for normal control, for example, 50% at step 411, and the motor drive method is changed to open-loop control at step 412. As a result, the motor 13 is driven according to the range switching operation with the 50% duty cycle, with the open-loop control so that the shift range of the range switching mechanism 11 is changed to the requested shift range. In the open-loop control, the energization phases of the motor 13 are alternately changed at a predetermined time interval, and the number of times the energization phases are changed is counted.Consequently, the motor 13 is rotated and driven to a target position based on the count value (for example, the number of times of change of the energization phases) according to the requested shift range.

[0060] In the fourth embodiment, when the motor drive method is changed to the open loop while the heat generation limiting control is being executed, the rotational speed of the motor 13 can be reliably reduced so that the energizing current of the motor 13 can be significantly reduced by the duty cycle control. Therefore, the temperature increase due to heat generation by the motor 13 can be limited.

[0061] It should be noted that a motor excitation method for open-loop control (a sequence for changing the energization phases) can be the same as a motor excitation method for feedback control or self-regulation and can be modified. The motor excitation method can be any of the following methods: 1-2-phase excitation method, 1-phase excitation method, and 2-phase excitation method. (Fifth embodiment)

[0062] In the Fig. 15 and Fig. In the fifth embodiment of the present invention shown in Fig. 16, a motor energization method is changed between one for the normal control and one for the heat generation limiting control so that the energizing current of the motor 13 can be reduced during the heat generation limiting control.

[0063] Specifically, in the fifth embodiment, in a method similar to the first embodiment, the operation number counter counts the number of times of consecutive operation of the range shift operation, which is consecutively operated with the short operation interval equal to or less than the predetermined time KT. When the count value CR of the operation number counter is less than the predetermined value KR, it is determined that the increase in temperature due to heat generation by the motor 13 has not exceeded the allowable level. Consequently, a Fig. 15 is executed such that the motor energization method is set as a 1-2 phase energization method in which single-phase energization and two-phase energization are alternately changed (switched) at step 501. As a result, the motor 13 is driven according to the range switching operation by the 1-2 phase energization method through the feedback control such that the shift range of the range switching mechanism 11 is changed to the requested shift range.

[0064] When the count value CR of the operation number counter becomes equal to or greater than the predetermined value KR, it is determined that the temperature increase due to heat generation by the motor 13 may exceed the allowable level if the range switching operation is repeated more frequently than this condition. Consequently, a Fig. 16 is executed such that the motor energization method is set to a 1-phase energization method in which the motor 13 is driven only by single-phase energization at step 502. As a result, the motor 13 is driven according to the range switching operation by the 1-phase energization method through feedback control such that the shift range of the range switching mechanism 11 is changed to the requested shift range.

[0065] When the motor excitation method is changed from the 1-2 phase excitation method to the 1 phase excitation method while the heat generation limiting control is being executed as described in the fifth embodiment, the energizing current of the motor 13 can be reduced, and therefore the increase in temperature due to heat generation by the motor 13 can be limited.

[0066] It should be noted that, in a case where the motor 13 is driven with the 2-phase excitation method during the normal control instead of the 1-2-phase excitation method as described in the fifth embodiment, the motor excitation method may alternatively be changed from the 2-phase excitation method to either the 1-2-phase excitation method or the 1-phase excitation method during the heat generation limiting control.

[0067] In the foregoing first to fifth embodiments, as shown in Fig. 2 to Fig. 4, and Fig. 10, a system including the two drive coils 38, 39 (corresponding to two lines of the drive coils 38, 39) of the motor 13 and the two motor drive circuits 34, 35 (corresponding to two lines of the motor drive circuits 34, 35) is provided as a fail-safe structure. The present invention is not limited thereto. The present invention may alternatively be applicable to a motor drive system equipped with only one line of the foregoing structure. (Sixth embodiment)

[0068] The Fig. 17 and Fig. The sixth embodiment of the present invention shown in Fig. 18 is an embodiment applied to a system provided for the purpose of fail-safe operation with the two drive coils 38, 39 of the motor 13 and the two motor drive circuits 34, 35 as shown in Fig. 2 to Fig. 4 and Fig. 10 shown.

[0069] In the sixth embodiment, in a method similar to the first embodiment, the operation number counter counts the number of times of consecutive operation of performing the range switching operation, which is consecutively operated with the short operation interval equal to or less than the predetermined time KT. When the count value CR of the operation number counter is smaller than the predetermined value KR, it is determined that the increase in temperature due to heat generation by the motor 13 has not exceeded the allowable level. Consequently, a Fig. 17 is executed such that, at step 601, a "two-wire energization" is set, in which the two drive coils 38, 39 of the motor 13 and the two motor drive circuits 34, 35 are both energized. As a result, the motor 13 is driven according to the range shift operation by the two-wire energization through the feedback control, so that the shift range of the range shift mechanism 11 is changed to the requested shift range.

[0070] If the count value CR of the operation number counter is equal to or greater than the predetermined value KR, it is determined that the temperature increase due to heat generation by the motor 13 may exceed the allowable level if the range switching operation is repeated more frequently than this condition. Consequently, a Fig. 18 is executed such that control is changed at step 602 to "one-wire energization" in which only one of the two drive coils 38, 39 of the motor 13 and a corresponding one of the two motor drive circuits 34, 35 is energized. As a result, the motor 13 is driven according to the range switching operation by the one-wire energization through the feedback control such that the shift range of the range switching mechanism 11 is changed to the requested shift range.

[0071] In the sixth embodiment, when the control is changed from the two-line energization to the one-line energization during the heat generation limiting control, the energizing current of the motor 13 can be reduced, and the increase in temperature due to heat generation by the motor 13 can be limited. (Seventh embodiment)

[0072] A rotation angle (actuation angle) of the motor 13 differs between the case where the P range is switched to the D range and the case where the N range is switched to the D range. As a result, the heat generation rates (heat generation amounts) generated by the drive coils 38, 39 of the motor 13 and the drive circuits 34, 35 differ between the two cases. When the range is switched from the N range to the D range (when the N range is switched to the D range), the rotation angle of the motor 13 is smaller than when the P range is switched to the D range, and thus the heat generation rate is smaller.Consequently, in a case where the switching operation from the N range to the D range is reflected in the operation frequency (the count value CR of the operation number counter), equivalent to the switching operation from the P range to the D range as in the first embodiment (. Fig. 6), the heat generation rate may be overestimated for the shift operation from the N range to the D range. Consequently, when the shift operation from the P range to the D range is repeated, the control may be changed to the heat generation limit control, even if the heat generation may still be allowable at that moment.

[0073] As a countermeasure against the foregoing drawback, in the present embodiment, the operation number of times of performing the range switching operation and the rotation angle of the motor 13 for each operation are both taken into account to determine the operation frequency. The seventh embodiment of the present invention carries out the foregoing, and it will be described with reference to Fig. 19 described.

[0074] A range switching operation frequency monitoring routine executed in the seventh embodiment of Fig. 19 is a modification of the range shift operation frequency monitoring routine of Fig. 6 described in the first embodiment. Specifically, a process at step 102 in the first embodiment is modified into processes at steps 101a, 102a in the present embodiment, and processes at other steps remain the same.

[0075] When the present routine is started, it is first determined at step 101 whether the range shift operation has been performed after the present routine of the previous time was executed. If the range shift operation has been performed, a count-up value ΔCR is calculated at step 101a using a map and the like according to the rotation angle (heat generation rate) of the engine 13 of the range shift operation of the current time. For example, the count-up value ΔCR is set as "1" in the shift operation from the P range to the D range (P to D shift operation), and the count-up value ΔCR is set as "0.3" in the shift operation from the N range to the D range (N to D shift operation), considering that the heat generation rate of the N to D shift operation is approximately 30% of that of the P to D shift operation.

[0076] Then, at step 102a, the count value CR of the operation number counter (number counter of consecutive operation) is incremented by the count-up value ΔCR calculated based on the rotation angle of the motor 13. Then, a similar process is executed, which is similar to the range switching operation frequency monitoring routine of Fig. 6 described in the first embodiment. Note that heat generation limiting control of step 109 is executed by any one of the methods described in the first to sixth embodiments.

[0077] In the foregoing embodiment, the count value CR of the operation number counter is incremented by the count-up value ΔCR according to the rotation angle (heat generation rate) of the motor 13 for each range shift operation (that is, the operation number counter is counted up). Therefore, the count-up value ΔCR for each range shift operation can be adjusted with the heat generation rate (the rotation angle of the motor 13) for each range shift operation. As a result, the count value CR of the operation number counter (detection information of the operation frequency of the range shift operation) can serve as information accurately corresponding to an actual heat generation rate by the motor 13. Therefore, even if the shift operation from the P range to the D range is repeated, the control is limited from changing to the heat generation limit control at a timing at which heat generation is still allowable.

[0078] It should be noted that in each of the foregoing first to seventh embodiments, a range switching device is configured to change a range to any of P, R, N, and D. However, in addition to this, for example, a second range (2) and a low range (L) may be added, and further, the present invention can be applied to a range switching device that changes the range only between the P range and a drive range (range other than the P range).

[0079] Moreover, a range shift operating device in each of the first to second embodiments includes the shift lever and the shift range detecting device 28. However, an alternative range shift operating device includes an operating component other than the shift lever for inputting a requested shift range requested by an occupant.

[0080] Furthermore, regarding the operation frequency of the range switching operation, the number of times the range switching operation is operated for a predetermined time may alternatively be counted. This count value can serve as detection information of the operation frequency of the range switching operation.

[0081] Furthermore, the present invention can be modified in various ways, and for example, a structure of the range switching mechanism 11 can be modified as required.

[0082] Additional advantages and modifications will be readily apparent to those skilled in the art. The invention, in its broader aspects, is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.

[0083] A control device comprises a range switching mechanism (11), a range switching actuator (28), an operation frequency monitor (33, 101 to 106, 101a, 102a), and a heat generation limit control device (33, 107, 109, 202, 302, 411, 412, 502, 602). The range switching mechanism (11) is configured to change a shift range using a motor (13). Through the range switching actuator (28), an occupant inputs a requested shift range. The motor is controlled according to the requested shift range such that the shift range is changed to the requested shift range. The actuation frequency monitoring device (33, 101 to 106, 101a, 102a) monitors an actuation frequency of the range switching actuation device (28).The heat generation limiting control means (33, 107, 109, 202, 302, 411, 412, 502, 602) switches control of the engine (13) to heat limiting control when the operation frequency of the range switching operation means (11) exceeds a predetermined frequency.

Claims

[1] Control device, with a range switching mechanism (11) in a vehicle, the range switching mechanism (11) being configured to change a switching range using a motor (13) as a drive source, a range shift operating device (28) through which an occupant of the vehicle inputs a requested shift range requested by the occupant, wherein the engine is controlled according to the requested shift range input by the range shift operating device (28) such that the shift range of the range shift mechanism (11) is changed to the requested shift range, an actuation frequency monitoring device (33, 101 to 106, 101a, 102a) which is designed to monitor an actuation frequency of the range switching actuation device (28), and a heat generation limiting control device (33, 107, 109, 202, 302, 411, 412, 502, 602) which is designed to switch a control of the engine (13) into a heat generation limiting control in which a heat generation rate is lower than that of a normal control when the actuation frequency of the range switching actuation device (28) exceeds a predetermined frequency, wherein the operation frequency monitoring means (33, 101, 101a, 102a) determines the operation frequency based on an operation number of times of performing the range switching operation and a rotation angle of the motor (13) for each range switching operation, and the operation frequency monitoring device (33, 101, 101a, 102a) comprises a consecutive operation number counter configured to increment a count value (CR) by a count-up value (ΔCR) based on the rotation angle of the motor (13) for each range switching operation, wherein the count value (CR) of the consecutive operation number counter is reset when a non-operation time exceeds a predetermined time, wherein the count value (CR) of the consecutive operation number counter is set as detected information of the operation frequency of the range switching operating device (28). [2] A control device for the range switching mechanism (11) according to claim 1, further comprising warning means (29) for warning the occupant while the heat generation limiting control is being executed. [3] A control device for the range switching mechanism (11) according to claim 1 or 2, wherein the operation frequency monitoring means (33, 101 to 106, 101a, 102a) comprises a consecutive operation number counter which increments a count value (CR) when a range switching operation is performed, the count value (CR) of the consecutive operation number counter being reset when a non-operation time exceeds a predetermined time, the count value (CR) of the consecutive operation number counter serving as detected information of the operation frequency of the range switching operating means (28). [4] A control device for the range switching mechanism (11) according to any one of claims 1 to 3, wherein the heat generation limiting control means (33, 107, 109) as the heat generation limiting controller temporarily prevents energization of the motor (13). [5] A control device for the range switching mechanism (11) according to any one of claims 1 to 3, wherein the heat generation limiting control means (33, 107, 109, 202, 302, 411, 412, 502, 602) as the heat generation limiting controller energizes the motor (13) with a smaller energizing current than that in the normal control. [6] A control device for the range shift mechanism (11) according to any one of claims 1 to 5, wherein the heat generation limiting control means (33, 107, 109, 202, 302, 411, 412, 502, 602) performs the heat generation limiting control for a predetermined engine cooling period because the operation frequency of the range shifting operation means (28) exceeds the predetermined frequency. [7] A control device for controlling a motor (13) to perform a range shift operation for switching a shift range of a range shift mechanism (11) of a vehicle, the control device comprising: an operation frequency detector (33) configured to detect an operation frequency of performing the range switching operation, and a heat generation limiting control device (33) configured to switch a control of the engine (13) to a heat generation limiting control in which a heat generation rate is less than a predetermined value when the operation frequency of the range switching operation exceeds a predetermined frequency, wherein the operation frequency detector (33) comprises a consecutive operation number counter which increases a count value (CR) when a range switching operation is performed, the count value (CR) of the consecutive operation number counter being reset when a non-operation time exceeds a predetermined time, the count value (CR) of the consecutive operation number counter serving as the operation frequency of the range switching operating device (28), and the counter of a consecutive number of operations increases the count value (CR) by an up-count value (ΔCR) which is based on the rotation angle of the motor (13) for each range switching operation. [8] A control apparatus according to claim 7, further comprising warning means (29) for warning an occupant of the vehicle while the heat generation limiting control is being executed. [9] The control device according to claim 7, wherein the operation frequency detector (33) determines the operation frequency based on an operation number of times of performing the range switching operation and a rotation angle of the motor (13) for each range switching operation. [10] The control device according to claim 7, wherein the heat generation limiting control means (33) as the heat generation limiting controller temporarily prevents energization of the engine (13). [11] The control device according to claim 7, wherein the heat generation limiting control means (33) as the heat generation limiting controller energizes the motor (13) with a smaller energizing current than that in the normal control. [12] The control device according to claim 7, wherein the heat generation limiting control means (33) determines whether a predetermined engine cooling time period has elapsed since a start time of the heat generation limiting control by the heat generation limiting control means (33), wherein the heat generation limiting control means (33) terminates the heat generation control when it is determined that the predetermined engine cooling time period has elapsed.

Images