Circuit control device

Abstract

Shift control device (1, 1B) for an automatic transmission (10) equipped with a shift-by-wire mechanism and converting and outputting drive energy from a drive unit (70, 70B), wherein the shift control device (1, 1B) comprises: - a selection device which receives a process for selecting a shift range of the automatic transmission (10) and outputs selection information corresponding to the process; - a shift control device (11, 42, 42B) which switches the shift range of the automatic transmission (10) according to the selection information output by the selector device; - a gradient detection device (82) which detects the gradient of a road surface; and - a determining device (41, 41B) which determines whether or not the drive unit (70, 70B) is capable of outputting drive energy, - wherein, in the event that the selection information for selecting a shift range different from the park range is output by the selector device when the shift range of the automatic transmission (10) is in the park range, the shift control device (11, 42, 42B) maintains the park range without switching the shift range of the automatic transmission (10), in the event that it has been determined that the drive unit (70, 70B) is in a state in which it is unable to output drive energy, and the gradient of the road surface is equal to or greater than a predetermined threshold.

Description

Technical area

[0001] The present invention relates to a shift control device, particularly to a shift control device for an automatic transmission having a shift-by-wire mechanism. State of the art

[0002] Recently, automatic transmissions equipped with a shift-by-wire (SWB) mechanism that electrically switches the shift range of an automatic transmission by detecting with a switch or the like the shift range selected by the driver and driving an actuator of an electric motor or the like based on the detection result have come into practical use.

[0003] To this end, a technology (a parking control device) is disclosed in Patent Literature 1, which, in an automatic transmission using a shift-by-wire mechanism, reduces the loud noise and shift shock when the parking state is released in a situation where a vehicle is parked on an uphill or downhill slope.

[0004] In such a parking control device, in a situation where a vehicle stops on an uphill or downhill slope, the following applies: In the event that the parking state is released, which is achieved by operating the shift lever, the hydraulic pressure control device of the automatic transmission is switched to the forward drive state (the D range) or the reverse drive state (the R range) based on the inclination direction of the vehicle, and after the forward drive state or the reverse drive state is established, the parking state (the parking rod) is released.

[0005] For this reason, according to this parking control device, before releasing the parking state, it is possible to apply a torque in the forward traveling direction or the reverse traveling direction to counteract the load due to the weight occurring in the output shaft of the vehicle, and it is possible to release the parking state smoothly.

[0006] Patent Literature 2 discloses a vehicle control device that does not require a complicated operation to start the engine even when an idle stop function has been performed. For this purpose, a mechanical automatic transmission, an idle stop device for stopping the engine when the vehicle is stationary, a slope detection device for detecting the slope of the road, and a control unit are provided. The control unit has a function for disengaging the clutch and selecting a gear suitable for the detected slope when the slope detected by the slope detection device is at or above a threshold value and operation of the idle stop device has been requested. BibliographyPatent literature Patent Literature 1: Japanese Unexamined Patent Application Publication JP 2002- 295 657 Patent literature 2: WO 2013 / 077 041 A1 Summary of the inventionTechnical problem

[0007] As described above, in the parking control device disclosed in Patent Literature 1, when the parking state is released in a situation where the vehicle is stopped on an uphill or downhill slope, it is possible to release the parking state smoothly. However, the parking control device disclosed in Patent Literature 1 does not consider the case where there is a request to release the parking state when the engine is stopped.

[0008] For this reason, when a vehicle stops on a downhill slope or the like, there is a risk that the parking state will be released if there is a request to release the parking state in a key-on state (i.e., a state in which the ignition key is turned on and electrical systems such as the shift-by-wire system are activated, but the engine has not been started).

[0009] This means that for the conventional technology described above (the shift-by-wire mechanism), when a vehicle is stopped on a road surface with a steep downhill gradient, for example, there is a risk that the vehicle will start moving regardless of the driver's intention due to the fact that the parking range is switched to another shift range in the key-on state in which the engine is stopped.

[0010] The present invention was conceived to solve the above-mentioned problem. Its object is to provide a shift control device capable of preventing a vehicle from inadvertently starting to move when, for example, a drive unit such as the engine cannot generate drive power, in a shift control device of an automatic transmission equipped with a shift-by-wire mechanism. Solution to the problem

[0011] According to the present invention, a shift control device for an automatic transmission equipped with a shift-by-wire mechanism and which converts and outputs drive power of a power unit comprises: a selector that receives an operation for selecting a shift range of the automatic transmission and outputs selection information corresponding to the operation; a shift control device that switches the shift range of the automatic transmission according to the selection information output from the selector; a slope detection device that detects the slope of a road surface; and a determination device that determines whether or not the power unit is capable of outputting drive power.

[0012] In the case where the selection information for selecting a shift range different from the parking range is output from the selector when the shift range of the automatic transmission is in the parking range, the shift control means maintains the parking range without switching the shift range of an automatic transmission in the case where it is determined that the power unit is in a state in which it is unable to output drive power and the gradient of the road surface is equal to or greater than a predetermined threshold.

[0013] According to the shift control device of the present invention, in the case where selection information for selecting a shift range other than the parking range is output, the parking range is maintained without switching the shift range of the automatic transmission in the case where the power unit is unable to output drive power and the gradient of the road surface is equal to or greater than a predetermined threshold.

[0014] For example, when stopping on a steeply downhill road surface, even if there is a request to release the parking state, in the state where the power unit is unable to output drive power (e.g., in the key-on state with the engine stopped), switching to the parking range is prevented and the parking range is maintained. Therefore, in an automatic transmission equipped with a shift-by-wire mechanism, when the power unit cannot generate drive power, it is possible to prevent the vehicle from starting to move unintentionally.

[0015] In the shift control device according to the present invention, it is preferable that, in the case where the selection information for selecting a shift range other than the parking range is output from the selecting means when the shift range of the automatic transmission is in the parking range, the shift control means switches the shift range of the automatic transmission based on the selection information in the case where it is determined that the power unit is in a state capable of outputting drive power or in the case where the gradient of the road surface is lower than the predetermined threshold.

[0016] In this case, the shift range of the automatic transmission is switched according to the driver's operation when the power unit can output drive power (e.g., when the engine is running) or when the road surface gradient is less than a predetermined threshold (when the gradient is zero or slight). That is, when the vehicle is not moving without the driver's intention, or when it is judged that even if the vehicle starts moving, it is in a controllable state, it is possible to switch the shift range according to the driver's request.

[0017] In the shift control device according to the present invention, it is preferable that a warning device is further provided which, in the case where the selection information for selecting a shift range other than the parking range is output from the selecting device when the shift range of the automatic transmission is in the parking range, issues a warning to a driver when the shift range of the automatic transmission is held in the parking range without being switched.

[0018] Therefore, when an operation is performed that is different from an operation (intention) of the driver, it is possible to warn the driver.

[0019] In the shift control device according to the present invention, it is preferable that the drive unit is a motor, and that the determining means determines whether or not the drive unit is in a state capable of outputting drive power by determining whether or not the motor is stopped.

[0020] Consequently, for a vehicle in which an engine is mounted as a drive unit, when the engine cannot generate drive power (ie, when the engine is stopped), it becomes possible to prevent the vehicle from moving unintentionally.

[0021] In the shift control device according to the present invention, it is preferable that the drive unit is a motor and an electric motor, and that the determining means determines whether or not the drive unit is in a state capable of outputting drive power by determining whether or not the motor is stopped and whether or not the electric motor is capable of driving.

[0022] Consequently, in a hybrid vehicle in which an engine and an electric motor are mounted as drive units, the following applies: When both the engine and the electric motor cannot generate drive energy, it becomes possible to prevent the vehicle from starting to move unintentionally.

[0023] In the shift control device according to the present invention, it is preferable that the drive unit is an electric motor, and that the determining means determines whether or not the drive unit is in a state capable of outputting drive power by determining whether or not the electric motor is capable of driving.

[0024] In an electric automobile in which an electric motor is mounted as a drive unit, if the electric motor cannot generate drive energy, it becomes possible to prevent the vehicle from starting to move unintentionally. Advantageous effects of the invention

[0025] According to the present invention, in a shift control device for an automatic transmission equipped with a shift-by-wire mechanism, for example, when the drive unit such as a motor cannot generate drive power, it becomes possible to prevent the vehicle from starting to move unintentionally. Short description of the drawings

[0026] The drawings show: Fig. 1 is a block diagram illustrating the structure of the circuit control device according to an embodiment. Fig. 2 a drawing illustrating the structure of the parking mechanism of an automatic transmission. Fig. 3 is a flowchart illustrating the processing procedure of the shift range switching operation by the shift control device according to an embodiment. Fig. 4 is a block diagram illustrating the structure of the circuit control device according to a modification. Embodiments of the invention

[0027] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Note that the same reference numerals are used for the same or equivalent portions and components. Also, in each of the drawings, the same reference numerals are assigned to the same elements, and overlapping descriptions of these elements are omitted.

[0028] First, using Fig. 1 the structure of the circuit control device 1 according to an embodiment is described. Fig. Fig. 1 is a block diagram illustrating the structure of the shift control device 1. Note that, here, the case of using a gasoline engine 70 (hereinafter referred to simply as "engine") as a drive unit that outputs drive power will be described as an example.

[0029] The shift control device 1 mainly includes: a selector 20 that receives operations for selecting the shift range of the automatic transmission 10, a select position determination unit 30 that generates and outputs selection information according to the selected shift range, and a shift-by-wire control unit 40 that switches the shift range of the automatic transmission 10 based on the selection information, and which, in the situation where a vehicle in which the shift-by-wire type automatic transmission 10 is mounted stops on a steep downhill slope, for example, has a function of preventing the vehicle from inadvertently starting to move when the engine 70 is stopped.

[0030] The automatic transmission 10 is connected to the output shaft of the engine 70, and it converts and outputs the drive energy from the engine 70 (note that in Fig. 1 the automatic transmission 10 and the engine 70 are shown schematically separately from each other).

[0031] A shift-by-wire actuator 11 (hereinafter referred to as "SBW actuator"), which is electrically connected to the shift-by-wire control unit 40 (hereinafter also referred to as "SBW-CU") and switches the shift range of the automatic transmission 10 according to a control signal (drive signal) from the shift-by-wire control unit 40, is assigned to the automatic transmission 10. Note that the shift-by-wire control unit 40 and the SBW actuator 11 may be integrally formed.

[0032] The SBW actuator 11 actuates a manually operable valve of the automatic transmission 10 according to the control signal from the shift-by-wire control unit 40 to switch the shift range of the automatic transmission 10. The SBW 11 includes an electric motor 12 that actuates the manually operable valve and a position sensor 13 that detects the position of the manually operable valve, i.e., the shift range of the automatic transmission 10.

[0033] Here, the automatic transmission 10 is designed to have five shift ranges, namely a parking range ((P) range), a reverse range ((R) range), a neutral range ((N) range), a forward range ((D) range) and a manual range ((M) range).

[0034] The following is a summary of the Fig. 2, a parking mechanism 110 of the automatic transmission 10 is described. The parking mechanism 110 is a mechanism that, when a parking switch 20a (described in detail below) is pressed, locks the rotation within the automatic transmission so that the wheels do not rotate. A locking plate 111 is connected to the output shaft of the SBW actuator 11 (an electric motor 12), which is driven by the shift-by-wire control unit 40.

[0035] A parking rod 112 is retractably connected to the locking plate 111 in the axial direction. A parking gear 114 is splined to the output shaft of the automatic transmission 10. A parking rod 113 is pivotally provided so as to engage with the parking gear 114.

[0036] When the parking switch 20a is pressed, the detent plate 111 pivots due to the rotation of the SBW actuator 11 (the electric motor 12), causing the parking rod 112 to advance in the axial direction. Then, the parking rod 113 pivots due to being pushed from the rear by the parking rod 112 and engages with the parking gear 114. This locks the rotation of the automatic transmission 10.

[0037] For description purposes, please refer again to Fig. 1. For example, a selector device 20 is provided in the center console of the vehicle, which receives operations to alternatively select the shift range of the automatic transmission 10 by the driver and outputs an electrical signal (a select signal) corresponding to the assumed selected operation.

[0038] The selector 20 has, for example, five switches, namely a parking switch (P) 20a that selects the parking range (the P range), a reverse switch (R) 20b that selects the reverse range (the R range), a neutral switch (N) 20c that selects the neutral range (the N range), a drive switch (D) 20d that selects the forward range (the D range), and a manual switch (M) 20e that selects the manual shift range (the M range).

[0039] For these five switches 20a to 20e, automatic reset switches (momentary switches) are preferably used, which assume the switched-on state only while being pressed by a finger or the like, and which return to the switched-off state as soon as the finger is removed.

[0040] The selector 20 is electrically connected to the select position determining unit 30 and outputs an electrical signal (a select signal) corresponding to the pressed switch to the select position determining unit 30. Note that a lever-type selector mechanism may also be used instead of the selector 20.

[0041] The select position determining unit 30 reads the electrical signal (ie, the switch input) from the selector 20, generates and outputs selection information corresponding to the selected shift range.

[0042] More specifically, the select position determining unit 30 is connected to the shift-by-wire control unit 40 (hereinafter also referred to as "SBW-CU"), and outputs the aforementioned selection information to the shift-by-wire control unit 40. That is, the selector 20 and the select position determining unit 30 function as the selector device mentioned in the claims.

[0043] As mentioned above, the shift-by-wire control unit 40 is electrically connected to the SBW actuator 11. The shift-by-wire control unit 40 is communicatively connected to the select position determination unit 30, a transmission control unit 50 (hereinafter also referred to as "TCU"), an engine control unit 60 (hereinafter also referred to as "ECU"), a vehicle dynamic control unit 80 (hereinafter also referred to as "VDCU"), and a meter control unit 90 (hereinafter also referred to as "MCU") via the CAN network 100.

[0044] Each of the control units will be described below. First, the transmission control unit 50 regulates the transmission control of the automatic transmission 10. An output shaft rotation sensor 16, a range switch 17 (lock switch: a switch that electrically locks the starter motor from rotating except in the P range and N range), and the like provided in the automatic transmission 10 are connected to the transmission control unit 50.

[0045] The transmission control unit 50 receives, through the CAN network 100, information such as the rotational speed of the engine 70 and the opening value of the accelerator pedal transmitted from the engine control unit 60, and information such as the shift range of the automatic transmission 10 transmitted from the shift-by-wire control unit 40.

[0046] Based on various information such as the referenced engine speed, the output shaft speed (vehicle speed), the accelerator opening value, and the shift range, the transmission control unit 50 drives a solenoid valve forming a control valve 15 and performs transmission control of the automatic transmission 10. Here, the control valve 15 controls the hydraulic pressure for shifting the automatic transmission 10.

[0047] More specifically, the control valve 15 supplies hydraulic pressure generated by an oil pump, for example, to a drive pulley or a driven pulley, using a spool and a solenoid valve that actuates the spool to open and close an oil passage. Note that the transmission control unit 50 transmits various information of the automatic transmission 10 to the shift-by-wire control unit 40 via the CAN network 100.

[0048] The engine control unit 60 acquires various information, such as the engine speed, the amount of intake air, the air-fuel ratio of the gas mixture, and the accelerator opening value, based on detection signals input from various sensors. Based on the various acquired information, it comprehensively controls the engine 70 by controlling fuel injection and ignition, as well as various actuators. A crank angle sensor 61, which detects the rotational position of the crankshaft of the engine 70, is connected to the engine control unit 60, and the engine speed is determined by the engine control unit 60 from the output of the crank angle sensor 61.

[0049] A hydraulic brake pressure sensor 81, which detects the master cylinder pressure of the brake actuator 83, and an acceleration sensor 82, which detects the front / rear and left / right accelerations, are connected to the dynamic control unit 80. Note that the acceleration sensor 82 can also function as a slope detection sensor, which detects the slope (inclination angle) of a road surface. The dynamic control unit 80 drives the brake actuator 83 according to a brake pedal operation value to decelerate the vehicle and detects the vehicle behavior using various sensors (e.g., a wheel speed sensor, a steering angle sensor, the acceleration sensor 82, a yaw rate sensor, and the like).

[0050] It prevents skidding and ensures vehicle stability during braking control by automatically applying pressure and torque to the motor 70. The dynamic control unit 80 transmits braking information (vehicle braking information) and road surface gradient information, etc., to the shift-by-wire control unit 40 via the CAN network 100. The dynamic control unit 80 and the acceleration sensor 82 function as the gradient detection device recited in the claims.

[0051] Specifically, in the case where the selection information for selecting a shift range other than the P range is output from the select position determining unit 30 when the shift range of the automatic transmission 10 is the P range, the meter control unit 90 outputs a warning and / or information to the driver when the shift range of the automatic transmission 10 is held in the P range without being switched.

[0052] In this case, the meter control unit 90 operates the display 91 to output a message such as "Please perform gear shifting after starting the engine," or to output a warning sound ("beep"). That is, the meter control unit 90 and the display 91 function as the warning device recited in the claims.

[0053] Based on the selection information received from the select position determination unit 30, the engine speed received from the engine control unit 60, the road surface gradient information received from the dynamic control unit 80, and various input information received from the transmission control unit 50, the shift-by-wire control unit 40 generates and outputs a control signal (an engine drive signal), and by driving the SBW actuator 11, switches the shift range of the automatic transmission 10.

[0054] For this reason, the shift-by-wire control unit 40 is functionally equipped with a determination unit 41 and a shift controller 42. The shift-by-wire control unit 40 includes a microprocessor that performs operations, a ROM that stores programs and the like for causing the microprocessor to execute processes, a RAM that stores various data such as operation results, a backup RAM in which the stored content is maintained by a 12V battery, and an input / output interface. By executing a program stored in the ROM by the microprocessor, the functions of the determination unit 41 and the shift controller 42 are realized in the shift-by-wire control unit 40.

[0055] The determination unit 41 determines whether or not the engine 70 is stopped based on the engine speed obtained from the engine control unit 60. That is, the determination unit 41 functions as the determining means recited in the claims. The determination unit 41 determines that the engine 70 is stopped when the engine speed is zero (or less than several tens of revolutions), and determines that the engine 70 is operating when the engine speed is not zero (or equal to or greater than several tens of revolutions). Note that the determination result from the determination unit 41 is output to the shift controller 42.

[0056] The shift controller 42 outputs a control signal (a motor drive signal) to the SBW actuator 11 according to the selection information output from the select position determination unit 30, and switches the shift range of the automatic transmission 10. That is, the shift controller 42 and the SBW actuator 11 function as the shift control device recited in the claims.

[0057] Specifically, in the case where selection information for selecting a shift range other than the P range is output from the select position determining unit 30 (that is, a request to release the parking state is output) when the shift range of the automatic transmission 10 is in the P range, the shift controller 42 maintains the P range without switching the shift range of the automatic transmission 10 (prohibits release from the parking state) in the case where the engine 70 is stopped and the gradient of the road surface is equal to or greater than a predetermined threshold (e.g., 30°).

[0058] Meanwhile, in the case where selection information for selecting a shift range other than the P range is output from the select position determining unit 30 (that is, a request to release the parking state is output) when the shift range of the automatic transmission 10 is in the P range, the shift controller 42 switches the shift range of the automatic transmission 10 based on the selection information in the case where the engine 70 is not stopped or in the case where the gradient of the road surface is smaller than a predetermined threshold (e.g., 30°).

[0059] Note that, as described above, in the case where the selection information for selecting a shift range other than the P range is output from the select position determination unit 30 when the shift range of the automatic transmission 10 is the P range, if the shift range of the automatic transmission 10 is held in the P range without being shifted, a warning and / or information is output to the driver. Specifically, the message "Please perform shifting after starting the engine" is output on the display 91, or a warning sound ("beep") is output.

[0060] The following is based on reference to Fig. 3 the operation of the circuit control device 1 is described. Fig. 3 is a flowchart illustrating the processing procedure of the shift range switching operation by the shift control device 1. The processing is repeatedly performed at every predetermined time (e.g., every 10 ms) in the shift-by-wire control unit 40.

[0061] In step S100, it is judged whether or not the current shift range of the automatic transmission 10 is the P range, and whether or not a request for a shift range other than the P range has been detected by the select position determining unit 30 (whether or not a range switch 20b to 20e other than the P range switch 20a has been pressed).

[0062] Here, if the current shift range is not the P range and / or if a shift request to a shift range other than the P range has not been detected, this processing is immediately exited. On the other hand, if the current shift range is the P range and a shift request to a shift range other than the P range has been detected, processing proceeds to step S102.

[0063] In step S102, it is judged whether or not the engine speed is zero (revolutions per minute) and whether the road surface gradient is greater than, for example, 30 (%). Here, if the engine speed is not zero (that the engine 70 is running) and / or if the road surface gradient is 30 (%) or less, processing proceeds to step S104. In turn, if the engine speed is zero (when the engine 70 is stopped) and the road surface gradient is greater than 30 (%), processing proceeds to step S106.

[0064] In step S104, according to the normal processing procedure, the SBW actuator 11 is driven based on the selection information output from the select position determination unit 30, and the shift range of the automatic transmission 10 is switched. After that, this processing is immediately exited.

[0065] In step S106, switching the shift range to a range other than the P range (releasing the parking state) is again prevented, and the P range is maintained. In step S106, a warning and / or information is also output to the driver. After that, this processing is immediately exited.

[0066] As described above, according to the present embodiment, in the case where selection information for selecting a shift range other than the P range is output, in the case where the engine 70 is stopped and the gradient of the road surface is equal to or greater than a predetermined threshold value (e.g., 30°), the P range is maintained without switching the shift range of the automatic transmission 10.

[0067] For example, when stopping on a steeply downhill road surface, even if there is a request to release the P range in the key-on state while the motor 70 is stopped, switching to the P range is prohibited, and the P range is maintained. For this reason, when the motor 70 cannot generate drive power, it becomes possible to prevent the vehicle from starting to move unintentionally.

[0068] Furthermore, according to the present embodiment, the shift range of the automatic transmission 10 is switched according to a driver's operation when the engine 70 is running or when the gradient of the road surface is lower than a predetermined threshold (e.g., 30°). That is, when the vehicle will not move without the driver's intention, or when it is judged that even if the vehicle starts moving, it is in a controllable state, it is possible to switch the shift range according to a driver's request.

[0069] According to the present embodiment, when the selection information for selecting a shift range other than the P range is output from the select position determination unit 30 when the shift range of the automatic transmission 10 is the P range, a warning is issued to the driver when the shift range of the automatic transmission 10 is held in the P range without being shifted. For this reason, when an operation different from an operation (intention) of the driver is performed, it is possible to warn the driver. First modification

[0070] In the above embodiment, a vehicle having an engine 70 as the drive unit (the source of driving power) is described as an example. However, the present invention can also be applied to a hybrid vehicle (HV) having an engine and an electric motor as the drive unit, and to an electric vehicle (EV) having an electric motor as the drive unit.

[0071] Therefore, next, a circuit control device 1B according to a modification using Fig. 4 described. Fig. 4 shows a block diagram illustrating the structure of the circuit control device 1B. In Fig. 4, the same reference numerals are assigned to the same individual elements, which are the same or equivalent to those of the above embodiment.

[0072] The shift control device 1B differs from the above-mentioned embodiment in that the vehicle to which this device is applied has an engine 70 and an electric motor 70B constituting the drive unit. The shift control device 1B also differs from the above-mentioned embodiment in that it is equipped with a determination section 41B instead of the determination section 41, and that it is equipped with a shift controller 42B instead of the shift controller 42. Since the remaining configuration is the same as or equivalent to the above-mentioned embodiment, detailed description thereof will be omitted here.

[0073] The determination section 41B determines whether or not the engine 70 is stopped, and determines, for example, whether or not the electric motor 70B is capable of driving based on, for example, the state of charge (SOC) of the battery received from an engine control unit / battery control unit 60B (MOT-CU / BCU) via the CAN network 100.

[0074] Specifically, the determination section 41B determines that the electric motor 70B is incapable of driving, for example, in the case where the SOC drops so that the electric motor 70B can no longer be driven. This means that the determination section 41B functions as the determination means recited in the claims. Note that the determination result of the determination section 41B is output to the shift controller 42B, similar to the above embodiment.

[0075] The shift controller 42B maintains the P range without switching the shift range of the automatic transmission 10 (preventing release of the P range state), in the case where the selection information for selecting a shift range other than the P range is output from the select position determining unit 30 when the shift range of the automatic transmission 10 is the P range, when the engine 70 is stopped, when the electric motor 70B is unable to drive, and when the gradient of the road surface is equal to or greater than a predetermined threshold (e.g., 30°).

[0076] The shift controller 42B switches the shift range of the automatic transmission 10 based on the selection information when the engine 70 is running, the electric motor 70B is capable of driving, or the slope of the road surface is smaller than a predetermined threshold (e.g., 30°), in the case where the selection information for selecting a shift range other than the P range is output from the select position determining unit 30 when the shift range of the automatic transmission 10 is the P range.

[0077] According to the present modification, in the case where the selection information for selecting a shift range other than the P range is outputted, in the case where the engine 70 is stopped, the electric motor 70B is incapable of driving, and the gradient of the road surface is equal to or greater than a predetermined threshold value (e.g., 30°), the shift range of the automatic transmission 10 is maintained in the P range without being switched.

[0078] For example, when stopping on a steep downhill road, even if there is a request to release the P range while the key is on, the P range is prevented from switching, and the P range is maintained. Therefore, when the electric motor cannot generate drive power, it is possible to prevent the vehicle from accidentally starting to move.

[0079] In addition, according to the present embodiment, when the engine 70 is operating, when the electric motor 70B is capable of driving, or when the gradient of the road surface is lower than a predetermined threshold (e.g., 30°), the shift range of the automatic transmission 10 is switched according to a driver's operation.

[0080] That is, when the vehicle will not move without the driver's intention, or when it is judged that even if the vehicle starts to move, it is in a controllable state, it is possible to switch the shift range according to a driver's request. Second modification

[0081] The present invention can also be applied to an electric vehicle (EV) having an electric motor constituting the drive unit, as described above. In this case, the determination section 41B determines whether or not the electric motor 70B (the drive unit) is in a state capable of outputting drive power by determining whether or not the electric motor 70B is capable of driving.

[0082] The shift controller 42B maintains the P range without switching the shift range of the automatic transmission 10 (preventing release of the P range state) in the case where the selection information for selecting a shift range other than the P range is output from the select position determining unit 30 when the shift range of the automatic transmission 10 is the P range, in the case where the electric motor 70B is unable to drive, and in the case where the gradient of the road surface is equal to or greater than a predetermined threshold (e.g., 30°).

[0083] The shift controller 42B switches the shift range of the automatic transmission 10 based on the selection information when the electric motor 70B is capable of driving or when the gradient of the road surface is smaller than a predetermined threshold (e.g., 30°) in the case where the selection information for selecting a shift range other than the P range is output from the select position determining unit 30 when the shift range of the automatic transmission 10 is the P range.

[0084] In an electric automobile in which the electric motor 70B is mounted as a drive unit, when the electric motor 70B cannot generate drive power, it becomes possible to prevent the vehicle from starting to move unintentionally.

[0085] Embodiments of the present invention have been described above, but the present invention is not limited to the above embodiment (or the modification), and various modifications are possible. For example, the system configuration of the present embodiment is only an example, and the system configuration of the present invention is not limited to the above embodiment. For example, the shift-by-wire control unit 40 and the SBW actuator 11 may be integrated. Also, the shift-by-wire control unit (SBW-CU) 40 and the transmission control unit (TCU) 50 may be a single unit. Also, the shift-by-wire control unit 40 and the select position determination unit 30 may be integrated into a single unit.

[0086] Also, the value of the threshold for determining that the slope of the road surface is slight or steep is not limited to 30°, and it can be set arbitrarily. List of reference symbols 1, 1B Circuit control device 10 automatic transmissions 11 Shift-by-wire actuator 20 dialing device 30 Dial position determination unit 40, 40B Shift-by-wire control unit (SBW-CU 41, 41B Determination unit 42, 42B shift control 50 Transmission Control Unit (TCU) 60 Engine Control Unit (ECU) 61 Crank angle sensor 60B Engine control unit / battery control unit 70 engine 70B electric motor 80 Dynamic Vehicle Control Unit (VDCU) 81 Hydraulic brake pressure sensor 82 Accelerometer (gradient sensor) 83 Brake actuator 90 Measuring device control unit (MCU) 91 ad 100 CAN network

Claims

[1] A shift control device (1, 1B) for an automatic transmission (10) equipped with a shift-by-wire mechanism and which converts and outputs drive energy of a drive unit (70, 70B), the shift control device (1, 1B) comprising: - a selection device which receives an operation for selecting a shift range of the automatic transmission (10) and outputs selection information corresponding to the operation; - a shift control device (11, 42, 42B) which switches the shift range of the automatic transmission (10) according to the selection information output by the selection device; - a gradient detection device (82) which detects the gradient of a road surface; and - a determining device (41, 41B) which determines whether or not the drive unit (70, 70B) is capable of outputting drive energy, - wherein, in the case where the selection information for selecting a shift range different from the parking range is output from the selecting means when the shift range of the automatic transmission (10) is in the parking range, the shift control means (11, 42, 42B) maintains the parking range without switching the shift range of the automatic transmission (10) in the case where it has been determined that the drive unit (70, 70B) is in a state in which it is unable to output drive power and the gradient of the road surface is equal to or greater than a predetermined threshold value. [2] The shift control device (1, 1B) according to claim 1, wherein, in the case where the selection information for selecting a shift range other than the parking range is output from the selecting means when the shift range of the automatic transmission (10) is in the parking range, the shift control means (11, 42, 42B) switches the shift range of the automatic transmission (10) on the basis of the selection information, in the case where it is determined that the drive unit (70, 70B) is in a state capable of outputting drive power, or in the case where the gradient of the road surface is smaller than the predetermined threshold. [3] A circuit control device (1, 1B) according to claim 1 or 2, further comprising: a warning device which, in the event that the selection information for selecting a shift range which is different from the parking range, is output by the selector when the shift range of the automatic transmission (10) is in the parking range, outputs a warning to a driver when the shift range of the automatic transmission (10) is held in the parking range without being shifted. [4] Circuit control device (1, 1B) according to one of claims 1 to 3, wherein the drive unit (70, 70B) is a motor (70), and wherein the determining means (41, 41B) determines whether or not the drive unit (70, 70B) is in a state capable of outputting drive power by determining whether or not the motor (70) is stopped. [5] Circuit control device (1, 1B) according to one of claims 1 to 3, wherein the drive unit (70, 70B) is a motor (70) and an electric motor (70B), and wherein the determining means (41, 41B) determines whether or not the drive unit (70, 70B) is in a state capable of outputting drive power by determining whether or not the engine (70) is stopped and whether or not the electric motor (70B) is capable of driving. [6] Circuit control device (1, 1B) according to one of claims 1 to 3, wherein the drive unit (70, 70B) is an electric motor, and wherein the determining means (41, 41B) determines whether or not the drive unit (70, 70B) is in a state capable of outputting drive power by determining whether or not the electric motor (70B) is capable of driving.

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