JP2009270626A - Controller of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of an automatic transmission capable of controlling shift position considering a vehicle load. <P>SOLUTION: A shift position control part 82 drives an actuator 42 so as to put the shift position of the automatic transmission 30 into the N position and sends a release/engagement instruction of a starting clutch to ECT-ECU 52, when a determination result that a driver's operation of selecting the shift position is an inhibit operation is received from a determination part 81. An inhibition part 83 sends an instruction to the shift position control part 82 to inhibit the change of the shift position to the N position, when a present vehicle speed is faster than a standard speed and a load state of the vehicle corresponds to a predetermined high load state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an automatic transmission, and more particularly to a technique for restricting a shift position selection operation by a driver based on a traveling state of a vehicle.

Japanese Patent Application Laid-Open No. 8-303542 (Patent Document 1) discloses a ratio control valve that controls a hydraulic pressure acting on an oil chamber of a drive pulley of a belt type continuously variable transmission to change a gear ratio. This ratio control valve is controlled by any combination of “close” / “close”, “open” / “close”, “open” / “open” of the two solenoid valves. When the reverse range is selected during forward travel of the vehicle, the two solenoid valves are controlled to be “closed” / “open” which is not any combination of the above in accordance with an inhibit command from the electronic control unit. As a result, the spool of the servo control valve moves from the normal position to the inhibit position, and the shift servo is forcibly driven to the neutral position.
JP-A-8-303542

  When the shift position is changed to the neutral position while the vehicle is traveling, transmission of the driving force from the power source (for example, the engine) to the driving wheels is interrupted. If the transmission of power from the power source to the drive wheels is interrupted in a state where the vehicle load is large, it is considered that the change in the behavior of the vehicle becomes large.

  For example, if the transmission of power from the power source to the drive wheels is interrupted when the vehicle is going down a slope, it is considered that the speed of the vehicle suddenly increases. On the other hand, if the transmission of power from the power source to the drive wheels is interrupted when the vehicle is going up a hill, the vehicle speed is considered to be greatly reduced. However, JP-A-8-303542 does not disclose control of the transmission in consideration of the load state of the vehicle.

  An object of the present invention is to provide a control device for an automatic transmission capable of controlling a shift position in consideration of a vehicle load.

  In summary, the present invention is provided in a power transmission path between a power source of a vehicle and a drive wheel, and changes a power transmission state from the power source to the drive wheel in accordance with a shift position selection operation by a driver. A control device for an automatic transmission that generates a forward state and a reverse state of a vehicle and a state where a power transmission path is cut off. The control device changes the state of the power transmission path so that the speed detection unit that detects the speed of the vehicle, the load state detection unit that detects the load state of the vehicle, and the shift position selection operation hinder the current traveling of the vehicle A determination unit that determines whether or not the operation is a predetermined operation, and a control unit that generates a cutoff state of the power transmission path when the determination unit determines that the shift position selection operation is a predetermined operation; And a prohibition section. The prohibition unit selects the shift position by the determination unit when the speed detected by the speed detection unit is equal to or higher than the reference speed and the load state detected by the load state detection unit has reached a predetermined high load state. Even though it is determined that the operation is a predetermined operation, the control unit is prohibited from changing the power transmission state from the current state.

  According to another aspect of the present invention, the power transmission path between the power source of the vehicle and the driving wheel is provided, and the power transmission state from the power source to the driving wheel is changed according to the driver's shift position selection operation. Thus, the control device for the automatic transmission generates a forward state and a reverse state of the vehicle and a power transmission path cut-off state. The control device changes the state of the power transmission path so that the speed detection unit that detects the speed of the vehicle, the load state detection unit that detects the load state of the vehicle, and the shift position selection operation hinder the current traveling of the vehicle A determination unit that determines whether or not the predetermined operation is to be performed, a speed detected by the speed detection unit is equal to or higher than a first speed, and the shift position selection operation by the determination unit is a predetermined operation If it is determined, a control unit that generates a cut-off state of the power transmission path and a prohibition unit are provided. The prohibition unit is when the speed detected by the speed detection unit is equal to or higher than a second speed larger than the first speed, and the load state detected by the load state detection unit has reached a predetermined high load state Although the determination unit determines that the shift position selection operation is a predetermined operation, the control unit is prohibited from changing the power transmission state from the current state.

  Preferably, the prohibition unit decreases the second speed as the load state detected by the load state detection unit increases.

  Preferably, the prohibition unit decreases the first speed as the load state detected by the load state detection unit increases.

  Preferably, the load state detection unit includes a load state detection unit that detects a load state of the vehicle as the load state.

  Preferably, the vehicle is configured to be able to pull an object. The load state detection unit includes a traction state detection unit that detects a traction state of the vehicle as the load state.

  Preferably, the load state detection unit includes a gradient detection unit that detects a state in which the vehicle is traveling on a road surface having a gradient as the load state.

  According to the present invention, when the vehicle load is large and the shift position selection operation by the driver is an operation for changing the state of the power transmission path so as to hinder the current traveling of the vehicle, the behavior of the vehicle by the operation is changed. It becomes possible to reduce the influence of.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

[Embodiment 1]
(Constitution)
A vehicle equipped with a control device according to Embodiment 1 of the present invention will be described with reference to FIG. The vehicle 200 includes an engine 1 (shown as E / G in the figure), a front wheel 2, a rear wheel 3, and a shift control system 10.

  The engine 1 is a power source of the vehicle 200 and generates a driving force. The engine 1 is an internal combustion engine that burns a mixture of fuel and air injected from an injector (not shown) in a combustion chamber of a cylinder. The piston in the cylinder is pushed down by the combustion, and the crankshaft is rotated. The power source of the vehicle 200 is not limited to an internal combustion engine such as the engine 1. For example, a motor may be mounted as a power source instead of the internal combustion engine, or a motor may be mounted as a power source in addition to the internal combustion engine.

  The shift control system 10 includes an automatic transmission 30 that changes the rotational speed of the crankshaft to a desired rotational speed by forming a desired speed ratio. Although not shown, the output gear of the automatic transmission 30 meshes with the differential gear. A drive shaft is connected to the differential gear by spline fitting or the like. Power is transmitted to the front wheel 2 via the drive shaft. That is, the automatic transmission 30 is provided in a power transmission path between the power source (engine 1) and the drive wheels (front wheels 2). The automatic transmission 30 switches between forward and reverse travel of the vehicle 200. Further, the power transmission path is interrupted by the automatic transmission 30.

  The shift control system 10 includes a so-called shift-by-wire shift operation device. Although details of the configuration of the shift control system 10 will be described later, in such a shift operation device, the operation of the shift lever by the driver is detected by a sensor, a switch, or the like, and among the plurality of shift positions according to the detection signal. One position is selected. The multiple shift positions include a forward travel position (hereinafter also referred to as “D position”), a reverse travel position (hereinafter also referred to as “R position”), and a neutral position (hereinafter also referred to as “N position”). Parking position (hereinafter also referred to as “P position”).

  FIG. 1 shows a state in which the vehicle 200 is traveling while towing the to-be-triggered object 5. The vehicle 200 is configured to be usable for such a purpose. For example, vehicles such as SUVs (Sports Utility Vehicles), pickup trucks, etc. are often used for towing by connecting a trailer, camper or boat mounted on the rear of the vehicle to the rear of the vehicle. To do.

  In the following description, it is assumed that the vehicle 200 is a vehicle (for example, the above-described SUV or a pickup truck) suitable for towing the towed object. However, the vehicle according to the present embodiment is not limited to a vehicle suitable for towing an object to be pulled, and can be applied to various types of vehicles.

  FIG. 2 is a diagram showing a configuration of the shift control system 10 according to the first embodiment. Referring to FIG. 2, shift control system 10 includes shift operation unit 20, actuator unit 40, shift switching mechanism 48, automatic transmission 30, SBW (Shift By Wire) -ECU (Electronic Control Unit) 50. ECT (Electronic Controlled Automatic Transmission) -ECU 52, EFI (Electronic Fuel Injection) -ECU 54, VSC (Vehicle Stability Control) -ECU 56, meter 58, oil temperature sensor 60, accelerator opening sensor 62, A vehicle speed sensor 64, a brake pressure sensor 66, and a load state detection unit 70 are included.

  The shift operation unit 20 includes a P switch 22 and a shift switch 24. The actuator unit 40 includes an actuator 42, an output shaft sensor 44, and an encoder 46.

  The shift control system 10 functions as a shift-by-wire system that switches the shift position by electrical control. Specifically, the shift switching mechanism 48 is driven by the actuator 42 to switch the shift position.

  The P switch 22 is a switch for switching the shift position between a parking position (hereinafter referred to as “P position”) and a position other than parking (hereinafter referred to as “non-P position”). And an input unit (not shown) for receiving an instruction from the driver. The driver inputs an instruction to put the shift position into the P position through the input unit. The input unit may be a momentary switch. A P command signal indicating an instruction from the driver received by the input unit is transmitted to the SBW-ECU 50. Note that the shift position may be switched from the non-P position to the P position by means other than the P switch 22 described above.

  The SBW-ECU 50 controls the operation of the actuator 42 that drives the shift switching mechanism 48 in order to switch the shift position between the P position and the non-P position, and indicates the current shift position state with an indicator (see FIG. (Not shown). When the driver depresses the input portion of the P switch 22 when the shift position is the non-P position, the SBW-ECU 50 switches the shift position to the P position and presents the indicator that the current shift position is the P position. To do.

  The actuator 42 is configured by, for example, a switched reluctance motor (hereinafter referred to as “SR motor”), and receives an actuator control signal from the SBW-ECU 50 to drive the shift switching mechanism 48. The encoder 46 rotates integrally with the actuator 42 and detects the rotation state of the SR motor. The encoder 46 of the present embodiment is a rotary encoder that outputs A-phase, B-phase, and Z-phase signals. The SBW-ECU 50 obtains a signal output from the encoder 46, grasps the rotation status of the SR motor, and controls energization for driving the SR motor.

  The shift switch 24 switches the shift position to a forward travel position (D position), a reverse travel position (R position), a neutral position (N position), or the like. It is a switch for releasing. A switching signal (hereinafter also referred to as a shift signal) indicating an instruction from the driver received by the shift switch 24 is transmitted to the SBW-ECU 50. That is, shift switch 24 transmits to SBW-ECU 50 a shift signal indicating a shift position corresponding to the position of an operation member (for example, shift lever) operated by the driver. The SBW-ECU 50 controls the shift position in the automatic transmission 30 by the actuator 42 based on a shift signal indicating an instruction from the driver, and presents the current shift position state to the meter 58.

  More specifically, the SBW-ECU 50 includes a shift position corresponding to the position of the shift lever based on the shift signal received from the shift switch 24, and a shift position based on the rotation amount of the actuator 42 detected by the encoder 46 and the like. If they are different, the actuator 42 is driven so as to switch to a shift position corresponding to the position of the shift lever.

  In the present embodiment, the automatic transmission 30 is described as being a stepped automatic transmission, but is not particularly limited thereto, and may be, for example, a continuously variable automatic transmission. The automatic transmission 30 is provided with a hydraulic circuit including various valves such as a manual valve, for example, and the shift position and the power transmission state are changed by a change in hydraulic pressure in the hydraulic circuit. More specifically, the automatic transmission 30 includes a planetary gear unit, that is, a planetary gear mechanism, and a brake element that changes a rotation mode of each rotation element (that is, sun gear, carrier, ring gear, etc.) of the planetary gear mechanism. And a frictional engagement element such as a clutch element.

  The manual valve is provided with a spool valve so as to slide inside the manual valve. When the spool valve is moved to a position corresponding to each shift position, the hydraulic pressure in the hydraulic circuit changes according to the moved position. In accordance with a change in hydraulic pressure in the hydraulic circuit, the engagement force in the friction engagement element changes, and the automatic transmission 30 changes to a state corresponding to each shift position. That is, the power transmission state from the engine to the drive wheels in the automatic transmission 30 (for example, any one of forward, reverse, and power cut states or a gear ratio) changes. The engagement force in these friction engagement elements is controlled by the ECT-ECU 52 using various solenoid valves provided in the hydraulic circuit.

  Shift switching mechanism 48 includes a shaft coupled to actuator 42. The shaft is provided with a detent plate which will be described later. The detent plate is connected to a spool valve of a manual valve of the automatic transmission 30 with a rod or the like interposed. The spool valve of the manual valve may be directly connected to the shaft.

  The shaft is rotated by an actuator 42. Further, the rotation of the shaft enables the spool valve to move to a position corresponding to each shift position. When the actuator 42 reaches the rotational position corresponding to the D position, the spool valve is moved to a position corresponding to the D position. Further, when the actuator 42 reaches the rotational position corresponding to the R position, the spool valve is moved to a position corresponding to the D position. Further, when the actuator 42 reaches the rotational position corresponding to the N position, the spool valve is moved to a position corresponding to the N position.

  In the present embodiment, the actuator 42 is described as being an electric motor that is rotationally driven. However, the actuator 42 is not particularly limited to rotational driving, and may be, for example, linearly driven. The actuator 42 is not particularly limited to an electric motor.

  The output shaft sensor 44 detects the rotational position of the shaft 102. Specifically, the output shaft sensor 44 is connected to the SBW-ECU 50 and transmits a signal indicating the rotation angle of the shaft 102 (rotational position signal) to the SBW-ECU 50. The SBW-ECU 50 detects the shift position based on the received signal indicating the rotational position. A range of predetermined output values corresponding to each shift position is determined in the memory of the SBW-ECU 50, and the SBW-ECU 50 determines that the received signal indicating the rotation angle of the shaft 102 corresponds to each shift position. By determining which of these corresponds to, the currently selected shift position is determined. In the present embodiment, the change in the output value of the output shaft sensor 44 has a linear relationship with the change in the rotational position (angle) of the shaft 102. The output shaft sensor 44 detects the rotation angle of the shaft 102 that is a physical quantity corresponding to the operation amount of the actuator 42.

  The oil temperature sensor 60 detects the temperature of hydraulic oil in the automatic transmission 30 (hereinafter referred to as oil temperature). The oil temperature sensor 60 is connected to the ECT-ECU 52 and transmits a signal indicating the detected oil temperature to the ECT-ECU 52. The ECT-ECU 52 transmits a signal indicating the oil temperature received from the oil temperature sensor 60 to the SBW-ECU 50.

  The accelerator opening sensor 62 detects the operation amount of the accelerator pedal. The accelerator opening sensor 62 is connected to the EFI-ECU 54 and transmits a signal indicating the detected accelerator opening to the EFI-ECU 54. The EFI-ECU 54 transmits a signal indicating the accelerator opening received from the accelerator opening sensor 62 to the SBW-ECU 50.

  The vehicle speed sensor 64 detects a physical quantity corresponding to the speed of the vehicle. For example, the vehicle speed sensor 64 may detect the rotational speed of the wheel, may detect the rotational speed of the output shaft of the automatic transmission 30, or may directly detect the speed of the vehicle. Good.

  In the present embodiment, vehicle speed sensor 64 is connected to VSC-ECU 56 and transmits a vehicle speed signal indicating the detected vehicle speed to VSC-ECU 56. The VSC-ECU 56 transmits a signal indicating the vehicle speed received from the vehicle speed sensor 64 to the SBW-ECU 50.

  The brake pressure sensor 66 detects the pressure in a brake master cylinder (not shown). The brake pressure sensor 66 is connected to the VSC-ECU 56 and transmits a signal indicating the detected brake pressure to the VSC-ECU 56. The VSC-ECU 56 transmits a signal indicating the brake pressure received from the brake pressure sensor 66 to the SBW-ECU 50.

  The oil temperature sensor 60, the accelerator opening sensor 62, the vehicle speed sensor 64, and the brake pressure sensor 66 may be directly connected to the SBW-ECU 50.

  The ECT-ECU 60 determines the automatic transmission based on the oil temperature detected by the oil temperature sensor 60 and the physical quantities related to the state of the automatic transmission 30 (for example, the turbine rotational speed, the output shaft rotational speed, and the engine rotational speed). 30 shift states are controlled.

  The EFI-ECU 54 controls the output of the engine, which is an internal combustion engine, based on the accelerator opening detected by the accelerator opening sensor 62 and physical quantities (for example, water temperature, intake air amount, etc.) related to the state of the engine. .

  The VSC-ECU 56 controls the brake hydraulic pressure based on a physical quantity (for example, wheel speed) related to the behavior of the vehicle in addition to the brake hydraulic pressure detected by the brake pressure sensor 66.

  The meter 58 presents the state of the vehicle equipment, the state of the shift position, and the like. Further, the meter 58 is provided with a display unit (not shown) for displaying instructions, warnings, and the like for the driver issued by the SBW-ECU 50.

  The load state detection unit 70 detects that the vehicle is in a predetermined high load state, and transmits a signal indicating the detection result to the SBW-ECU 50.

  FIG. 3 is a functional block diagram of the SBW-ECU 50 of FIG. Note that the configuration shown in FIG. 3 may be realized by software or hardware. Referring to FIG. 3, SBW-ECU 50 includes a determination unit 81, a shift position control unit 82, and a prohibition unit 83.

  The determination unit 81 determines whether or not the shift position selection operation by the driver is an operation different from the normal operation according to the shift signal from the shift switch (see FIG. 2). Then, determination unit 81 outputs the determination result to shift position control unit 82 and prohibition unit 83. “Unusual operation” means an operation of changing the state of the vehicle (the state of the power transmission path) so as to hinder the current traveling of the vehicle. For example, when the current shift position is “forward travel position”, “reverse travel position” or “parking position” corresponds to “operation different from normal”. Further, when the current shift position is “reverse travel position”, “forward travel position” or “parking position” corresponds to “operation different from normal”.

  This “unusual operation” corresponds to an operation that should be restricted for controlling the behavior of the vehicle. Therefore, hereinafter, the above-mentioned “unusual operation” will also be referred to as “inhibit operation”. The inhibit operation corresponds to the “predetermined operation” in the present invention.

  The shift position control unit 82 drives the actuator 42 in accordance with the shift signal and transmits an instruction to release or engage the starting clutch to the ECT-ECU 52. Furthermore, when the shift position control unit 82 receives a determination result from the determination unit 81 that the driver's shift position selection operation is an inhibit operation, the shift position of the automatic transmission 30 is set to the N position. The actuator 42 is driven and a start clutch release / engagement instruction is transmitted to the ECT-ECU 52. Further, when the shift position control unit 82 receives an instruction from the prohibition unit 83 to prohibit the shift to the N position, the shift position control unit 82 determines from the determination unit 81 that the shift position selection operation of the driver is an inhibit operation. Even if it is received, the shift position is not shifted to the N position, and the current shift position is maintained. That is, the shift position is maintained as it is (for example, D position).

  The prohibition unit 83 receives a signal indicating the vehicle speed from the vehicle speed sensor 64, and determines whether or not the current vehicle speed is greater than the reference speed. Further, the prohibition unit 83 determines whether or not the load state corresponds to a predetermined high load state based on the vehicle load state detected by the load state detection unit 70. The prohibition unit 83 shifts the shift position to the N position with respect to the shift position control unit 82 when the current vehicle speed is higher than the reference speed and the load state of the vehicle corresponds to a predetermined high load state. Send instructions to prohibit it.

  FIG. 4 is a diagram illustrating a configuration example of the load state detection unit 70. Referring to FIG. 4, load state detection unit 70 includes a gradient detection unit 71, a loading state detection unit 72, and a traction state detection unit 73.

  The gradient detection unit 71 detects the gradient of the road surface and sends the detection result to the prohibition unit 83. That is, the gradient detector 71 detects a state in which the vehicle is traveling on a road surface having a gradient. As the gradient detection unit 71, for example, a G sensor or a gyro sensor can be used.

  The loading state detection unit 72 detects the loading state of the vehicle and sends the detection result to the prohibition unit 83. The loading state detection unit 72 is configured by, for example, a weight sensor that detects the total weight of the vehicle.

  The method by which the weight sensor detects the total weight of the vehicle is not particularly limited. For example, the weight sensor detects the total weight of the vehicle from the detection result of the displacement sensor that detects the amount of bending deformation of the suspension device of the vehicle. As another example, for example, the relationship between the operation amount of the accelerator pedal and the acceleration of the vehicle when the total weight of the vehicle is changed may be defined in advance by an arithmetic expression or a map. The loading state detection unit 72 is based on the calculation formula (or map), the operation amount of the accelerator pedal detected by the accelerator opening sensor, and the acceleration calculated from the speed detected by the vehicle speed sensor. Is calculated.

  Further, for example, the relationship between the vehicle height and the loaded weight may be defined in advance by an arithmetic expression or a map. In this case, the loading state detection unit 72 detects, for example, the degree of contraction of the coil spring included in the suspension device in order to detect the vehicle height. The loading state detection unit 72 calculates the loading weight from the detected vehicle height and the arithmetic expression (or map), and calculates the total weight of the vehicle from the loading weight. The loading state detection unit 72 sends the detected total weight of the vehicle to the prohibition unit 83.

  The tow state detection unit 73 detects whether the vehicle is towed and sends the detection result to the prohibition unit 83. For example, as the traction state detection unit 73, a sensor (or a switch) that is provided at a connection portion of the vehicle with a to-be-towed object and detects whether the vehicle and the to-be-towed object are connected can be used. In addition, as the tow state detection unit 73, a switch that is operated by a user and sets the state of the vehicle to a state suitable for towing the object to be pulled may be used. The traction state detection unit 73 may be a device that determines that a traction state has occurred when the weight of the vehicle detected by the weight sensor is greater than a predetermined value.

  The prohibition unit 83 determines whether or not the road surface gradient detected by the gradient detection unit 71 is greater than a predetermined angle. Further, the prohibition unit 83 determines whether or not the loading state detected by the loading state detection unit 72 has reached a predetermined state (for example, the total weight is greater than the predetermined weight). In addition, the prohibition unit 83 determines whether or not the vehicle is towing an object to be pulled from the detection result of the tow state detection unit 73. Then, the prohibition unit 83 determines that the road surface gradient is larger than a predetermined angle, a determination result that the loading state of the vehicle has reached a predetermined state, and a determination result that the vehicle is towing the towed object. When at least one of the following is obtained, it is determined that the vehicle is in a high load state. That is, the “predetermined high load condition” is satisfied when at least one of the determination results is obtained.

  In FIG. 4, the load state detection unit 70 includes a gradient detection unit 71, a loading state detection unit 72, and a traction state detection unit 73. The structure containing any one or two may be sufficient.

  FIG. 5 is a configuration diagram of the shift switching mechanism 48. In the following, positions other than the P position are designated as non-P positions (including R, N, and D positions, and in addition to the D position, the 1st fixed D1 position and the 2nd fixed D2 position may also be included). explain.

  Referring to FIG. 5, actuator 42 is connected to shaft 102 with deceleration mechanism 68 interposed. That is, the rotation speed of the actuator 42 is transmitted to the shaft 102 decelerated by the decelerating mechanism 68. The reduction mechanism 68 is constituted by a plurality of gears, for example.

  The shift switching mechanism 48 is fixed to the shaft 102 rotated by the actuator 42, the detent plate 100 that rotates as the shaft 102 rotates, the rod 104 that operates as the detent plate 100 rotates, and the output shaft of the automatic transmission 30. A parking lock gear 108, a parking lock pole 106 for locking the parking lock gear 108, a detent spring 110 and a roller 112 for limiting the rotation of the detent plate 100 and fixing the shift position. The detent plate 100 is driven by the actuator 42 to switch the shift position. The actuator 42 is provided with an encoder 46. The encoder 46 functions as a counting unit that acquires a count value corresponding to the rotation amount of the actuator 42.

  The encoder 46 is a sensor that detects a rotor rotation angle by generating a pulse signal during rotation by a magnet and a Hall IC arranged at equal intervals on the rotor of the electric motor. The encoder 46 increases the counter value as the amount of rotation of the actuator 42 increases (or decreases the counter value if the rotating direction is the negative direction). A signal indicating a counter value in the encoder 46 (hereinafter also referred to as a count signal) is transmitted to the SBW-ECU 50. The SBW-ECU 50 detects the rotation amount of the actuator 42 based on the increment or decrement of the counter value. Alternatively, the SBW-ECU 50 may detect the rotation amount of the shaft 102 based on the increment or decrement of the counter value and the reduction ratio in the reduction mechanism 68.

  In the perspective view of FIG. 5, only the valley (P position position) of the detent plate 100 is shown, but actually, as shown in the enlarged plan view of FIG. There are four valleys corresponding to the four positions of R and P. In the following description, switching between the P position and the non-P position will be described assuming that the positions D, N, and R are (collectively) non-P positions.

  FIG. 5 shows a state when the shift position is a non-P position. In this state, since the parking lock pole 106 does not lock the parking lock gear 108, the rotation of the drive shaft of the vehicle is not hindered. When the shaft 42 is rotated clockwise by the actuator 42 from this state, the rod 104 is pushed in the direction of the arrow A shown in FIG. 2 via the detent plate 100, and parking is performed by the taper portion provided at the tip of the rod 104. The lock pole 106 is pushed up in the direction of arrow B shown in FIG. As the detent plate 100 rotates, one of the two valleys provided at the top of the detent plate 100, that is, the roller 112 of the detent spring 110 in the non-P position position 120, climbs over the mountain 122 and goes to the other valley. That is, the process moves to the P position position 124. The roller 112 is provided on the detent spring 110 so as to be rotatable in its axial direction. When the detent plate 100 rotates until the roller 112 reaches the P position position 124, the parking lock pole 106 is pushed up to a position where the protruding portion of the parking lock pole 106 is fitted between the teeth of the parking lock gear 108. As a result, the drive shaft of the vehicle is mechanically fixed, and the shift position is switched to the P position.

  When the rotation position of the actuator 42 (relative position of the roller 112 on the detent plate 100) based on the rotation amount detected by the encoder 46 is within a predetermined range corresponding to the P position, the SBW-ECU 50 shifts the shift position. Is in the P position.

  On the other hand, in SBW-ECU 50, based on the rotation amount detected by encoder 46, the rotation position of actuator 42 is within a predetermined range corresponding to a non-P position (for example, any one of D, R, and N). Sometimes, it is determined that the shift position is a non-P position.

  The SBW-ECU 50 detects the rotation amount of the actuator 42 based on the counter value detected by the encoder 46.

  The SBW-ECU 50 sets the position of at least one shift position among the plurality of shift positions based on the rotational position of the actuator regulated by the regulating member. Therefore, SBW-ECU 50 determines which shift position is the P position, R position, N position, or D position based on the counter value detected by encoder 46.

  Note that the SBW-ECU 50 may determine the position of the shift position based on the output value of the output shaft sensor 44 instead of or in addition to the encoder 46.

(Shift position control)
FIG. 6 is a flowchart showing a shift position control process of the automatic transmission by the SBW-ECU 50 shown in FIG. The processing shown in this flowchart is called from the main routine and executed, for example, at regular time intervals or when a predetermined condition is satisfied (for example, when the driver operates the shift lever).

  Referring to FIGS. 6 and 3, when the process is started, determination unit 81 receives the shift signal and determines whether or not the inhibit operation is performed (step S1). Specifically, the determination unit 81 compares the shift position indicated by the shift signal with the current shift position. For example, when the current shift position is the forward travel position (D position) and the shift position indicated by the shift signal is a position for controlling the vehicle to prevent forward travel of the vehicle (for example, the P position or the R position). It is determined that the inhibit operation has been performed. Determination unit 81 outputs the determination result to shift position control unit 82 and prohibition unit 83.

  If it is determined that the inhibit operation has not been performed (NO in step S1), the entire process returns to the main routine. Therefore, the current position is held as it is. On the other hand, when it is determined that the inhibit operation is performed (YES in step S1), the process proceeds to step S2.

  In step S2, the prohibition unit 83 determines whether or not the current speed of the vehicle is equal to or higher than the reference value VA based on the detection result of the vehicle speed sensor 64. If the current vehicle speed is equal to or higher than reference value VA (YES in step S2), the process proceeds to step S3. On the other hand, when the current vehicle speed is less than reference value VA (NO in step S2), prohibiting unit 83 causes shift position control unit 82 to shift the shift position of the automatic transmission from the current position to the N (neutral) position. Allow that. In this case, the process proceeds to step S5.

  As the reference value VA, for example, a predetermined value (for example, 30 km per hour) can be used as a general traveling speed of the vehicle. However, the value of the reference value VA is not limited to the above value.

  In step S <b> 3, the prohibition unit 83 determines whether or not the vehicle is in a high load state based on the detection result of the load state detection unit 70. As described above, for example, the load state detection unit 70 detects the road surface gradient, the total weight of the vehicle, and the presence or absence of traction. The prohibiting unit 83 generates at least one of a state in which an angle indicating a road surface gradient is larger than a predetermined angle, a state in which the total weight of the vehicle is larger than a predetermined weight, and a state in which the vehicle is towing the towed object. It is determined that the vehicle is in a high load state.

  When it is determined that the vehicle is in a high load state (YES in step S3), prohibiting unit 83 causes shift position control unit 82 to shift the shift position of the automatic transmission from the current position to the N position. Send instructions to ban. In this case, the process proceeds to step S4. On the other hand, when it is determined that the vehicle is not in a high load state (NO in step S3), prohibition unit 83 allows shift position control unit 82 to shift the shift position of the automatic transmission from the current position to the N position. To do. In this case, the process proceeds to step S5.

  In step S4, the shift position control unit 82 holds the current shift position in response to an instruction from the prohibition unit 83.

  In step S5, the shift position control unit 82 shifts the current shift position to the N position based on the result determined by the determination unit 81 that the inhibit operation has been performed.

  When the process of step S4 or step S5 is completed, the entire process returns to the main routine.

  As described above, in the first embodiment, when the driver's shift position selection operation corresponds to the inhibit operation (YES in step S1), the vehicle speed and the load state of the vehicle are determined (steps S2 and S3). If the vehicle speed is less than the reference value VA, or if the vehicle load state does not reach a predetermined high load state even if the vehicle speed is greater than the reference value VA, the current shift position is shifted to the N position ( Step S5). On the other hand, when the vehicle speed is equal to or higher than the reference value VA and the load state of the vehicle has reached a predetermined high load state, the current shift position is held (step S4).

  When the shift position is changed from the current position (assuming it is the forward position) to the N position, the transmission of power from the engine 1 to the front wheels 2 is interrupted. When the vehicle speed is less than the reference value VA, it is considered that the change in the vehicle speed is small even if the shift position is changed to the N position. Similarly, if the vehicle load state does not reach a predetermined high load state even when the vehicle speed is higher than the reference value (for example, when the vehicle is traveling on a road having a small slope angle), the shift position is set to the N position. Even if it is changed to, the change in vehicle speed is considered to be small. Therefore, it is possible to reduce the influence on the behavior of the vehicle due to an erroneous operation by the driver.

  On the other hand, for example, when the vehicle travels with a heavy load loaded thereon, or when a towed object is connected to the rear portion of the vehicle, the vehicle load increases. Assume that the transmission of power from the engine 1 to the front wheels 2 is interrupted when the vehicle is traveling in such a state. For example, when the vehicle is traveling on a road with a small slope angle or an uphill road, the vehicle speed decreases. It is considered that the rate of decrease in vehicle speed increases as the load state of the vehicle increases (for example, as the road slope angle increases). On the other hand, when the vehicle is going down a slope, the force generated in the forward direction of the vehicle increases as the loading weight of the vehicle increases. Further, since the engine braking force does not act on the drive wheels, the force for preventing the vehicle from traveling is reduced. Therefore, it is considered that the speed of the vehicle suddenly increases.

  Thus, in the state where both the vehicle speed and the vehicle load are large, it is considered that the behavior of the vehicle changes greatly when the transmission of power from the engine 1 to the front wheels 2 is interrupted. When the behavior of the vehicle changes greatly, for example, the driver must perform an operation for moving the vehicle as intended.

  According to the first embodiment, when the vehicle speed is higher than the reference speed and the load state of the vehicle corresponds to a predetermined high load state, the shift position is held at the current position even if the inhibit operation is performed. The This can prevent a large change in the behavior of the vehicle due to the change from the current shift position to the N position. Further, it is possible to avoid the operation of the driver accompanying the change in the behavior of the vehicle. Therefore, according to Embodiment 1, it is possible to prevent a decrease in operability of the vehicle.

[Embodiment 2]
Since the configuration of the vehicle according to the second embodiment is similar to the configuration of the vehicle according to the first embodiment (the configuration shown in FIGS. 1 to 5), the following description will not be repeated. The difference between the second embodiment and the first embodiment is the control process for the shift position of the automatic transmission. The shift position control process according to the second embodiment will be described below.

  FIG. 7 is a flowchart showing a shift position control process according to the second embodiment. The processing shown in this flowchart is called from the main routine and executed by the SBW-ECU 50 (see FIG. 3 and the like) at regular time intervals or when a predetermined condition is satisfied (for example, when the driver operates the shift lever). The

  Referring to FIGS. 7 and 6, the flowchart of FIG. 7 is different from that of step S2 in that the processes of steps S11 and S12 are executed and the process of step S6 is added. Different from the flowchart. The processing of other steps in the flowchart of FIG. 7 is the same as the processing of the corresponding steps in FIG. Therefore, in the following, an outline of processing similar to that in the flowchart of FIG. 6 will be described.

  Referring to FIGS. 7 and 3, when the process is started, determination unit 81 receives the shift signal and determines whether or not the inhibit operation is performed (step S1). If it is determined that the inhibit operation has not been performed (NO in step S1), the entire process returns to the main routine. On the other hand, when it is determined that the inhibit operation is performed (YES in step S1), the process proceeds to step S11.

  In step S11, the prohibition unit 83 determines whether or not the current speed of the vehicle is equal to or higher than the first reference value V1 based on the detection result of the vehicle speed sensor 64. If the current vehicle speed is equal to or higher than reference value V1 (YES in step S11), the process proceeds to step S12. On the other hand, when the current vehicle speed is less than reference value V1 (NO in step S11), the process proceeds to step S6. Here, the reference value V1 is, for example, a value (for example, 10 km per hour) determined in advance as a speed when the vehicle travels at a low speed. The speed is an example of the reference value V1, and the reference value V1 is not limited to this.

  In step S12, the prohibition unit 83 determines whether or not the current speed of the vehicle is equal to or higher than the second reference value V2 based on the detection result of the vehicle speed sensor 64. If the current vehicle speed is equal to or higher than reference value V2 (YES in step S12), the process proceeds to step S3. On the other hand, when the current vehicle speed is less than reference value V2 (NO in step S12), prohibition unit 83 causes shift position control unit 82 to shift the shift position of the automatic transmission from the current position to the N position. to approve. In this case, the process proceeds to step S5. As the reference value V2, for example, the same value as the reference value VA shown in the flowchart of FIG. 6 can be adopted, but it is not limited to this.

  In step S <b> 3, the prohibition unit 83 determines whether or not the vehicle is in a high load state based on the detection result of the load state detection unit 70. When it is determined that the vehicle is in a high load state (YES in step S3), prohibiting unit 83 causes shift position control unit 82 to shift the shift position of the automatic transmission from the current position to the N position. Send instructions to ban. In this case, the process proceeds to step S4. On the other hand, when it is determined that the vehicle is not in a high load state (NO in step S3), prohibition unit 83 allows shift position control unit 82 to shift the shift position of the automatic transmission from the current position to the N position. To do. In this case, the process proceeds to step S5.

  In step S4, the shift position control unit 82 holds the current shift position in response to an instruction from the prohibition unit 83.

  In step S5, the shift position control unit 82 shifts the current shift position to the N position based on the result determined by the determination unit 81 that the inhibit operation has been performed.

  In step S <b> 6, the prohibition unit 83 sends an instruction for invalidating the determination result indicating that the operation is an inhibit operation to the shift position control unit 82. As a result, the shift position control unit 82 shifts the current shift position to the position selected by the shift signal.

  When any one of steps S4, S5, and S6 is completed, the entire process returns to the main routine.

  Also in the second embodiment, when the shift position selection operation of the driver corresponds to the inhibit operation (YES in step S1), the vehicle speed and the load state of the vehicle are determined (steps S11, S12, S3). If the vehicle speed is greater than or equal to the reference value V1 and less than the reference value V2, or if the vehicle load state does not reach the predetermined high load state even if the vehicle speed is greater than the reference value V2, the N position from the current shift position (Step S5). As a result, similarly to the first embodiment, when the vehicle load is small or the vehicle speed is small to some extent, the influence on the behavior of the vehicle due to an erroneous operation by the driver can be reduced.

  On the other hand, when the vehicle speed is equal to or higher than the reference value V2 and the load state of the vehicle has reached a predetermined high load state, the current shift position is held (step S4). As in the first embodiment, this makes it possible to avoid a change in the behavior of the vehicle due to the change from the current shift position to the N position when the load state of the vehicle is high.

  Further, in the second embodiment, when the vehicle speed is less than the first reference value V1, the prohibition unit 83 invalidates the result of the determination unit 81 determining that the shift position selection operation is the inhibit operation. Thereby, when the vehicle speed is less than the first reference value V1, the shift position is changed according to the shift position selection operation by the driver (step S6).

  For example, when the vehicle is stopped in a predetermined section, it is possible that the forward and backward movements are repeated at a speed equal to or lower than the reference value V2. According to the first embodiment, when the shift position is changed from the forward travel position to the reverse travel position at a speed equal to or lower than the reference value V2, the shift position selection operation by the driver is performed regardless of the magnitude of the speed. It is determined that the operation is an inhibit operation. Therefore, the shift position temporarily shifts to the N position. Therefore, the driver has to redo the shift position selection operation.

  According to the second embodiment, when the vehicle speed is less than the first reference value V1, the shift position is changed according to the driver's shift position selection operation, so that the vehicle repeats forward and reverse at low speed (for example, It is possible to prevent the operability of the vehicle from being deteriorated when the vehicle as described above is stopped in a predetermined section.

[Modification of Embodiment 2]
In the modification described below, the reference value V2 or V1 is changed according to the load state. The configuration of the vehicle according to this modification is the same as that of the first embodiment. Further, the shift position control process according to this modification is the same as the process of the flowchart shown in FIG.

(First modification)
In this modification, the prohibition unit 83 (see FIG. 3) changes the reference value V2 according to the load state of the vehicle detected by the load state detection unit 70. Specifically, the prohibition unit 83 decreases the reference value V2 as the load state of the vehicle increases.

  The prohibition unit 83 stores, for example, a map that defines the relationship between the slope angle and the reference value V2 and / or the relationship between the total weight of the vehicle and the reference value V2. Then, the prohibition unit 83 sets the reference value V2 based on the gradient angle detected by the load state detection unit 70 and / or the total weight of the vehicle and the map.

  FIG. 8 is a diagram illustrating an example of a map stored in the prohibition unit 83. Referring to FIG. 8, the relationship between the slope angle and the reference value V2 is defined as the first map, and the relationship between the total weight of the vehicle and the reference value V2 is defined as the second map. In the first map, V2 is determined to be smaller as the gradient angle is larger. Similarly, in the second map, V2 is determined to be smaller as the total weight of the vehicle is larger. In these maps, the reference value V2 when the vehicle is towing the towed object is set to be smaller than the reference value V2 when the vehicle is not towing the towed object.

  When the prohibition unit 83 calculates the reference value V2 from the first and second maps, the values calculated from each map may be different from each other. In this case, the prohibition unit 83 can employ the smallest value among the plurality of calculated values as the reference value V2.

  Next, another example of a method for calculating the reference value V2 is shown. According to this example, the reference value V2 is calculated by multiplying a constant by a coefficient corresponding to the load state. The prohibition unit 83 determines a coefficient from the gradient angle detected by the load state detection unit 70 and the total weight of the vehicle, and calculates the reference value V2 by multiplying the coefficient by a constant.

  FIG. 9 is a diagram illustrating coefficients stored in the prohibition unit 83. Referring to FIG. 9, a coefficient corresponding to the gradient angle is determined. A coefficient corresponding to the total weight is determined. In addition, a coefficient corresponding to the presence or absence of traction is determined. The larger the slope angle, the smaller the coefficient. Similarly, the greater the total weight, the smaller the coefficient. The coefficient a when the to-be-towed object is being pulled is smaller than the coefficient b when the to-be-towed object is not towed.

  As shown in FIG. 9, for example, a coefficient corresponding to the reference value of the slope angle and the reference value of the total weight of the vehicle is set to 1. That is, the reference value of the gradient angle is 0 degree, and the reference value of the total weight of the vehicle is A1.

  For example, it is assumed that the load state detection unit 70 detects that the gradient angle is 2 degrees, the total weight is detected as A3, and the to-be-towed object is being pulled. In this case, the prohibition unit 83 calculates the reference value V2 by multiplying the constant (A) by the coefficients x2, y2, and a. That is, V2 = x2 * y2 * a * A.

  It is considered that the greater the load state of the vehicle, the greater the change in the behavior of the vehicle when the transmission of power from the engine 1 to the front wheels 2 is interrupted even if the speed is low. In the first modification, the reference value V2 is decreased as the load state of the vehicle increases. This can further reduce the possibility that the behavior of the vehicle will change greatly.

(Second modification)
In this modification, the prohibition unit 83 (see FIG. 3) changes the reference value V1 according to the load state of the vehicle detected by the load state detection unit 70. Specifically, the prohibition unit 83 decreases the reference value V1 as the load state of the vehicle increases.

  As a method of changing the reference value V1, a method of calculating the reference value V1 using a map (see FIG. 8) as in the first modification example, or a reference value by multiplying a constant according to a load state by a constant. A method of calculating V1 (see FIG. 9) can be employed. Therefore, the following description will not be repeated for a specific method for changing reference value V1.

  When the vehicle speed is constant, the torque applied to the drive wheels increases as the load state of the vehicle increases. Therefore, when the reference value V1 is fixed, there is a possibility that the shock felt by the occupant when the shift position is switched from the forward travel position to the reverse travel position even if the vehicle speed is V1 or less. According to the second modification, the reference value V1 is decreased as the load state of the vehicle increases, so that the shift position is switched from the forward travel position to the reverse position (assuming this operation is a normal operation). The shift position temporarily shifts to the N position. As a result, the shock that occurs when the shift position is switched can be reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram of the vehicle carrying the control apparatus which concerns on Embodiment 1 of this invention. It is the figure which showed the structure of the shift control system 10 which concerns on Embodiment 1. FIG. It is a functional block diagram of SBW-ECU 50 of FIG. 3 is a diagram illustrating a configuration example of a load state detection unit 70. FIG. 3 is a configuration diagram of a shift switching mechanism 48. FIG. FIG. 4 is a flowchart showing a shift position control process of the automatic transmission by the SBW-ECU 50 shown in FIG. 3. 10 is a flowchart showing a shift position control process according to the second embodiment. 6 is a diagram illustrating an example of a map stored in a prohibition unit 83. FIG. FIG. 6 is a diagram illustrating coefficients stored in a prohibition unit 83.

Explanation of symbols

  1 engine, 2 front wheels, 3 rear wheels, 5 towed object, 10 shift control system, 20 shift operation section, 22 P switch, 24 shift switch, 30 automatic transmission, 40 actuator section, 42 actuator, 44 output shaft sensor, 46 Encoder, 48 Shift switching mechanism, 58 Meter, 60 Oil temperature sensor, 62 Accelerator opening sensor, 64 Vehicle speed sensor, 66 Brake pressure sensor, 68 Deceleration mechanism, 70 Load state detection unit, 71 Gradient detection unit, 72 Loading state detection , 73 traction state detection unit, 81 determination unit, 82 shift position control unit, 83 prohibition unit, 100 detent plate, 102 shaft, 104 rod, 106 parking lock pole, 108 parking lock gear, 110 detent spring, 200 vehicle.

Claims (7)

Providing a power transmission path between the power source of the vehicle and the drive wheels, and changing the power transmission state from the power source to the drive wheels according to a shift position selection operation by the driver, thereby moving the vehicle forward A control device for an automatic transmission for generating a state and a reverse state, and a cutoff state of the power transmission path,
A speed detector for detecting the speed of the vehicle;
A load state detection unit for detecting a load state of the vehicle;
A determination unit that determines whether or not the shift position selection operation is a predetermined operation for changing a state of the power transmission path so as to prevent current traveling of the vehicle;
When the determination unit determines that the shift position selection operation is the predetermined operation, a control unit that generates the cutoff state of the power transmission path;
When the speed detected by the speed detection unit is equal to or higher than a reference speed and the load state detected by the load state detection unit has reached a predetermined high load state, the shift is performed by the determination unit. A prohibiting unit that prohibits the control unit from changing the transmission state of the power from a current state even though it is determined that the position selection operation is the predetermined operation. Automatic transmission control device. Providing a power transmission path between the power source of the vehicle and the drive wheels, and changing the power transmission state from the power source to the drive wheels in accordance with a shift position selection operation by the driver, A control device for an automatic transmission for generating a state and a reverse state, and a cutoff state of the power transmission path,
A speed detector for detecting the speed of the vehicle;
A load state detection unit for detecting a load state of the vehicle;
A determination unit that determines whether or not the shift position selection operation is a predetermined operation for changing a state of the power transmission path so as to prevent current traveling of the vehicle;
When the speed detected by the speed detection unit is equal to or higher than a first speed and the determination unit determines that the shift position selection operation is the predetermined operation, the power transmission path A control unit for generating the shut-off state of
The speed detected by the speed detector is equal to or higher than a second speed greater than the first speed, and the load state detected by the load state detector has reached a predetermined high load state. In this case, the transmission state of the power is changed from the current state to the control unit even though the determination unit determines that the shift position selection operation is the predetermined operation. A control device for an automatic transmission, comprising: a prohibiting unit that prohibits The prohibited part is
The control apparatus for an automatic transmission according to claim 2, wherein the second speed is reduced as the load state detected by the load state detection unit increases. The prohibited part is
The control apparatus for an automatic transmission according to claim 2, wherein the first speed is decreased as the load state detected by the load state detection unit increases. The load state detector
The control apparatus for an automatic transmission according to any one of claims 1 to 4, further comprising a loading state detection unit that detects a loading state of the vehicle as the load state. The vehicle is configured to be capable of towing an object,
The load state detector
The automatic transmission control device according to any one of claims 1 to 4, further comprising a traction state detection unit that detects a traction state of the vehicle as the load state. The load state detector
5. The control device for an automatic transmission according to claim 1, further comprising: a gradient detection unit that detects a state in which the vehicle is traveling on a road surface having a gradient as the load state. 6.

Images