JP2013183504A - Play elimination control device of electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a play elimination control device that can shorten time required for play elimination, while controlling generation of gear rattle and impact by the play elimination of a power transmission system of an electric vehicle.SOLUTION: When reverse direction range switching to switch a shift range from one of a D range and an R range to the other of the D range and the R range through an N range is performed by a shift operation, play elimination control to output play elimination torque of a direction corresponding to a shift range after switching to a reverse direction range from a motor is executed over a predetermined time period. In the play elimination control, the play elimination torque of the maximum value is output in the period for the first half of the predetermined time period, and the motor is controlled so that the play elimination torque may decrease continuously from the maximum value gradually.

Description

  The present invention is applied to an electric vehicle having at least a motor as a drive source, and relates to a backlash control device for packing backlash of a power transmission system from an electric motor to drive wheels.

  Electric vehicles such as an electric vehicle using a motor as a drive source and a hybrid car using an engine and a motor as a drive source are commercially available.

  In the electric vehicle, the motor is driven in the rotation direction corresponding to the shift range. That is, when the D range (forward range) is selected by a shift operation by the driver, the motor is driven in the forward direction, and when the R range (reverse range) is selected, the motor is driven in the reverse direction. Then, the driving force of the motor is transmitted to the driving wheels via the speed reducer, so that the vehicle moves forward or backward.

  A large number of gears are provided in the power transmission system from the motor to the drive wheels, and there is play due to backlash of the gears. Therefore, when the vehicle is started after the shift range is switched from the D range to the R range while the vehicle is stopped, or after the shift range is switched from the R range to the D range while the vehicle is stopped, the power transmission system has a backlash. After that, the driving force of the motor is transmitted to the driving wheel. If a large driving force is output from the motor when the backlash is packed, the teeth of one gear meshing with each other will strongly collide with the teeth of the other gear, generating a rattling noise or impact. Or

  Therefore, in the electric vehicle capable of traveling at a low speed (creep traveling) by the creep torque output from the motor with the D range or R range selected, the shift range is switched from the D range to the R range during stopping. Alternatively, when the vehicle is started after the shift range is switched from the R range to the D range while the vehicle is stopped, the backlash that is smaller than the creep torque is output from the motor, and the backlash of the power transmission system is reduced. It has been proposed to perform filling control.

JP 2011-250648 A

  The rotation speed ω of the motor increases in proportion to the time t during which the backlash torque T is output from the motor. The output power P of the motor is defined by the product T · ω of the backlash torque T and the rotational speed ω. In order to prevent the occurrence of rattling noise and impact during backlash control, the limit output power Plmt that generates rattling noise and impact is obtained in advance, and the output power P of the motor is set to the limit output power Plmt. The backlash torque T must be set small so as not to exceed.

  However, if the backlash torque T is small, the speed of increase of the motor rotational speed ω is slow, and it takes a long time to obtain the rotation angle necessary for backlash filling.

  An object of the present invention is to provide a backlash control device that can reduce the time required for backlash while suppressing the occurrence of rattling noise and impact due to backlash of a power transmission system of an electric vehicle.

  In order to achieve the above object, an electric vehicle to which the backlash control device according to the present invention is applied uses at least a motor as a drive source. The backlash control device includes reverse range switching permission means for allowing reverse range switching in which the shift range is switched from one of the forward range and the reverse range to the other of the forward range and the reverse range through a neutral range, and a shift operation. In response to detection of the reverse range switching by the reverse range switch detection means, the shift range after the reverse range switch from the motor is detected. And backlash control means for executing backlash control for outputting a backlash torque in a direction corresponding to the predetermined time.

  When the reverse range switching is performed in which the shift range is switched from one of the forward range and the reverse range to the other of the forward range and the reverse range by the shift operation, in response to this, the motor drives the drive wheels of the electric vehicle. In order to close the backlash existing in the power transmission system up to the back, the backlash control for outputting the backlash torque in the direction corresponding to the shift range after the reverse direction range switching from the motor is executed for a predetermined time.

  In the backlash control according to one aspect of the present invention, the maximum backlash torque is output from the motor within the first half of the predetermined time. Thereby, the rotation speed of a motor can be raised rapidly at the time of the start of backlash control. Thereafter, the magnitude of the backlash torque is gradually reduced from the maximum value. As a result, when the rotation angle of the motor reaches the rotation angle necessary for backlashing, the output power of the motor can be made smaller than the limit output power that generates a rattling noise or an impact.

  As a result, when the elapsed time from the start of the backlash control is taken on the horizontal axis and the rotational speed of the motor after the start of the backlash control is taken on the vertical axis, the motor of the The shape of the region sandwiched between the graph showing the temporal change in the rotation speed and the horizontal axis approaches a quadrangle, and the rotation angle of the motor necessary for backlashing can be obtained in a short time.

  Therefore, it is possible to reduce the time required for backlash while suppressing the occurrence of rattling noise and impact due to backlash of the power transmission system of the electric vehicle.

  Also, in the backlash control means according to another aspect of the present invention, backlash torque is output in a pulse form from the motor.

  Then, at the beginning of the predetermined time, a pulse-like backlash torque having a relatively large amplitude is output. Thereby, the rotation speed of the motor 2 can be raised at a stretch at the initial stage of the backlash control. Then, the amplitude of each pulsed backlash torque is gradually reduced so that the amplitude of the finally output pulsed backlash torque becomes relatively small. As a result, when the rotation angle of the motor 2 reaches the rotation angle necessary for backlashing, the output power of the motor 2 can be made smaller than the limit output power that generates a rattling noise or an impact.

  As a result, when the elapsed time from the start of the backlash control is taken on the horizontal axis and the rotational speed of the motor after the start of the backlash control is taken on the vertical axis, the motor of the The shape of the region sandwiched between the graph showing the temporal change in the rotation speed and the horizontal axis approaches a quadrangle, and the rotation angle of the motor necessary for backlashing can be obtained in a short time.

  Therefore, it is possible to reduce the time required for backlashing while suppressing the occurrence of rattling noise and impact due to backlashing of the power transmission system of the electric vehicle 1.

  According to the present invention, it is possible to reduce the time required for backlashing while suppressing the occurrence of rattling noise and impact due to backlashing of the power transmission system of the electric vehicle.

FIG. 1 is a diagram schematically showing the configuration of an electric vehicle according to an embodiment of the present invention. FIG. 2 is a normal rotation torque map that defines the relationship between the vehicle speed and the output torque of the motor. FIG. 3 is a reverse torque map that defines the relationship between the vehicle speed and the output torque of the motor. FIG. 4 is a flowchart showing the flow of processing until the backlash control is executed. FIG. 5 is a diagram illustrating temporal changes in the shift switching permission flag, the reverse direction range switching flag, and the backlash torque. FIG. 6 is a diagram illustrating temporal changes in the output torque, the rotation speed, and the output power of the motor when the backlash is performed with a constant backlash torque. FIG. 7 is a diagram illustrating temporal changes in motor output torque, rotation speed, and output power in the backlash control according to the first embodiment. FIG. 8 is a diagram illustrating temporal changes in the output torque, rotation speed, and output power of the motor in the backlash control according to the second embodiment. FIG. 9 is a diagram showing temporal changes in motor output torque, rotation speed, and output power in the backlash control according to the third embodiment. FIG. 10 is a diagram illustrating temporal changes in the output torque, rotation speed, and output power of the motor in the backlash control according to the modification of the third embodiment. FIG. 11 is a diagram illustrating temporal changes in the output torque, rotation speed, and output power of the motor in the backlash control according to the modification of the second embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically showing the configuration of an electric vehicle according to an embodiment of the present invention.

  The electric vehicle 1 is an electric vehicle that uses a motor 2 as a drive source.

  The left and right front wheels 3FL, 3FR of the electric vehicle 1 are provided so as to be rotatable around the shaft by holding a shaft extended from the hub on a hub bearing provided on the hub carrier. The left and right rear wheels 3RL, 3RR are connected to the left end portion of the rear wheel shaft 4RL extending in the left-right direction and the right end portion of the rear wheel shaft RR, respectively.

  The output shaft of the motor 2 is connected to the rear wheel shafts 4RL and 4RR via a reduction gear 5 including a gear train composed of a plurality of gears. The driving force generated by the motor 2 is decelerated by the speed reducer 5 and transmitted to the rear wheels 3RL and 3RR via the differential gear 5D and the rear wheel shafts 4RL and 4RR. During braking of the electric vehicle 1, the motor 2 functions as a generator, and the kinetic energy of the electric vehicle 1 is transmitted to the output shaft of the motor 2 via the speed reducer 5 as the rotational force of the rear wheel shafts 4RL, 4RR. The rotation of the output shaft of the motor 2 is regenerated to electric power.

  The high voltage battery 7 is connected to the motor 2 via the inverter 6.

  A high voltage battery 7 is connected to the inverter 6. The high voltage battery 7 is provided to store electric power for driving / generating the motor 2. When the motor 2 is driven, DC power output from the high voltage battery 7 is converted into AC power by the inverter 6, and the AC power after the conversion is supplied to the motor 2 as drive power. On the other hand, when the motor 2 generates power, AC power output from the motor 2 is converted into DC power by the inverter 6, and the high-voltage battery 7 is charged by the DC power after the conversion.

  In addition, an auxiliary battery 9 is connected to the inverter 6 via a DC-DC converter 8. The electric power stored in the auxiliary battery 9 is supplied to the auxiliary machine provided in the electric vehicle 1. Further, when the motor 2 generates power, the DC power output from the inverter 6 is stepped down by the DC-DC converter 8 and the auxiliary battery 9 is charged by the stepped-down DC power.

  In addition, the electric vehicle 1 is provided with a plurality of ECUs (electronic control units) including a CPU and a memory. The ECU includes a vehicle ECU 11, a motor ECU 12, a brake ECU 13, and a battery ECU 14. The vehicle ECU 11, the motor ECU 12, the brake ECU 13, and the battery ECU 14 can communicate with each other by, for example, a CAN (Controller Area Network) communication protocol.

  The vehicle ECU 11 controls the entire vehicle 1. The vehicle ECU 11 includes a shift sensor 21 that detects whether the shift range is a D range (forward range), an R range (reverse range), an N range (neutral range), or a P range (parking range), an accelerator pedal ( Detection signals from various sensors such as an accelerator sensor 22 that detects an operation amount of a brake pedal (not shown), a brake sensor 23 that detects an operation amount of a brake pedal (not shown), and a vehicle speed sensor 24 that detects a vehicle speed are input. The vehicle ECU 11 gives commands necessary for controlling each part of the vehicle 1 to the motor ECU 12, the brake ECU 13, and the battery ECU 14 based on detection signals input from various sensors. Further, the vehicle ECU 11 controls the DC-DC converter 8 in order to step down the DC power output from the inverter 6 to a voltage suitable for charging the auxiliary battery 9.

  The motor ECU 12 controls the inverter 6 based on the motor torque command value given from the vehicle ECU 11 and controls the electric power supplied from the inverter 6 to the motor 2. Further, the motor ECU 12 controls the inverter 6 in order to convert AC power regenerated by the motor 2 into DC power.

  The brake ECU 13 controls the brake actuator 31 based on a command given from the vehicle ECU 11. Under the control of the brake actuator 31, braking force is applied from the front wheel brakes 32FL, 32FR to the front wheels 3FL, 3FR, respectively, and braking force is applied from the rear wheel brakes 32RL, 32RR to the rear wheels 3RL, 3RR, respectively.

  The battery ECU 14 monitors the charge / discharge amount of the high voltage battery 7, and transmits the chargeable / dischargeable electric energy of the high voltage battery 7 to the vehicle ECU 11 based on a command given from the vehicle ECU 11.

  FIG. 2 is a normal rotation torque map that defines the relationship between the vehicle speed and the output torque of the motor.

  The forward torque map shown in FIG. 2 is a motor torque command that is a target value of torque output from the motor 2 when the motor ECU 2 drives the motor 2 in the forward direction in order to move the electric vehicle 1 forward. Referenced to set the value. The forward torque map is stored in the memory of the vehicle ECU 11.

  For example, the accelerator pedal operation amount when the accelerator pedal is not depressed (accelerator off) is 0%, and the accelerator pedal operation amount when the accelerator pedal is fully depressed (accelerator fully open) is 100%. The operation amount range (operation amount range) is set, and one forward rotation torque map is created for each operation amount region.

  The forward rotation torque map referred to when the accelerator pedal operation amount is 0% is output from the motor 2 as the vehicle speed increases in the range from 0 km / h to a predetermined vehicle speed in the forward direction of the electric vehicle 1. The positive torque (torque in the forward rotation direction) is set to be small. When the vehicle speed exceeds a predetermined vehicle speed in the forward direction, the motor 2 is set to output regenerative torque. In consideration of so-called rollback, the motor 2 is set to output a positive torque with respect to the vehicle speed in the reverse direction of the electric vehicle 1. When the operation amount of the accelerator pedal is 0%, the positive torque output from the motor 2 is a creep torque.

  FIG. 3 is a reverse torque map that defines the relationship between the vehicle speed and the output torque of the motor.

  The reverse torque map shown in FIG. 3 is a target value of torque output from the motor 2 when the motor ECU 11 drives the motor 2 in the reverse direction opposite to the normal direction in order to move the electric vehicle 1 backward. Referenced to set a certain motor torque command value. The reverse torque map is stored in the memory of the vehicle ECU 11.

  For example, the accelerator pedal operation amount when the accelerator pedal is not depressed (accelerator off) is 0%, and the accelerator pedal operation amount when the accelerator pedal is fully depressed (accelerator fully open) is 100%. The operation amount range (operation amount range) is set, and one reverse torque map is created for each operation amount region.

  The reverse torque map referred to when the accelerator pedal operation amount is 0% is output from the motor 2 as the vehicle speed increases in the range from 0 km / h to the predetermined vehicle speed in the reverse direction of the electric vehicle 1. Negative torque (torque in the reverse direction) is set to be small. When the vehicle speed exceeds a predetermined vehicle speed in the reverse direction, the motor 2 is set to output regenerative torque. In consideration of so-called rollback, the motor 2 is set to output a negative torque with respect to the vehicle speed in the forward direction of the electric vehicle 1. When the operation amount of the accelerator pedal is 0%, the negative torque output from the motor 2 is a creep torque.

  FIG. 4 is a flowchart showing the flow of processing until the backlash control is executed. FIG. 5 is a diagram illustrating temporal changes in the shift switching permission flag, the reverse direction range switching flag, and the backlash torque.

  While the start switch of the electric vehicle 1 is turned on and the electric vehicle 1 is in the travelable state (travel READY), the process shown in FIG. 4 is repeatedly executed by the vehicle ECU 11.

  In the process shown in FIG. 4, the vehicle ECU 11 refers to the torque map corresponding to the current shift range (before the reverse range switching) and sets the motor torque command value (step S1). For example, when the current shift range is the R range, the reverse torque map shown in FIG. 3 is referred to and the motor torque command value is set. When the current shift range is the D range, the normal torque map shown in FIG. 2 is referred to and the motor torque command value is set. A torque corresponding to the motor torque command value is output from the motor 2.

  Further, it is repeatedly checked whether or not the vehicle speed in the forward direction or the reverse direction is equal to or lower than the inhibit vehicle speed Viht (for example, 5 km / h) at which the range can be switched (step S2).

  If the vehicle speed in the forward or reverse direction is equal to or lower than the inhibit vehicle speed Viht (YES in step S2), shift range switching is permitted (step S3), and is provided in the memory of the vehicle ECU 11 as shown in FIG. The shift switching permission flag is turned on (1 is set in the shift switching permission flag).

  Thereafter, the vehicle ECU 11 determines whether reverse range switching has been performed (step S4). Reverse range switching is an operation in which the driver operates a shift lever (not shown) to switch the shift range from one of the D range and R range to the other of the D range and R range via the N range. .

  While the vehicle speed is greater than the inhibit vehicle speed Viht (NO in step S2) or until the reverse range switching is performed (NO in step S4), the torque map corresponding to the shift range before the reverse direction range switching is referred to. Then, a motor torque command value is set (step S1).

  When reverse range switching is performed (YES in step S4), as shown in FIG. 5, the reverse range switch flag provided in the memory of the vehicle ECU 11 is turned on for a predetermined time (1 is set in the reverse range switch flag). Set). Then, while the reverse direction range switching flag is turned on, backlash control for closing backlash existing in the power transmission system from the motor 2 to the rear wheels 3RL and 3RR of the electric vehicle 1 is executed (step S5). .

  When the backlash control is completed, a torque map corresponding to the shift range after the reverse range switching is referred to, and a motor torque command value is set (step S6). For example, when the shift range after the reverse range switching is the D range, the forward torque map shown in FIG. 2 is referred to and the motor torque command value is set. Further, when the shift range after the reverse direction range switching is the R range, the reverse torque map shown in FIG. 3 is referred to set the motor torque command value. A torque corresponding to the motor torque command value is output from the motor 2.

  FIG. 6 is a diagram illustrating temporal changes in the output torque, the rotation speed, and the output power of the motor when the backlash is performed with a constant backlash torque.

  FIG. 6 shows the output torque, rotation speed, and output power of the motor 2 when a backlash torque having a constant magnitude T is output from the motor 2 over a period of 3 t (hereinafter referred to as “in the case of torque T”). The change over time is indicated by a solid line, and the output torque, the rotational speed, and the rotation speed of the motor 2 when the backlash torque having a constant magnitude of 3T is output from the motor 2 over time t (hereinafter referred to as “in the case of torque 3T”). The change in output power with time is indicated by a two-dot chain line.

  Comparing the case of torque T with the case of torque 3T, the rotational speed of the motor 2 is proportional to the time during which the backlash torque is output from the motor 2, so that in the case of the torque 3T, the case of the torque T Will rise three times as fast.

  On the other hand, since the backlash amount by the backlash torque (rotational angle of the motor 2) is a time integral value of the rotational speed of the motor 2, the backlash amount in the case of the torque 3T is the backlash amount in the case of the torque T. 1/3. In the case of the torque 3T, the maximum value (peak value) of the output power of the motor 2 represented by the product of the backlash torque and the rotation speed of the motor 2 is the maximum value of the output power of the motor 2 in the case of the torque T. It is three times larger than (peak value). Therefore, in the case of torque 3T, if the backlash torque having a magnitude of 3T is continuously output from the motor 2 over time t, before reaching the rotation angle θtarget necessary for backlash filling, The teeth of the meshing gears collide with each other, and rattling noise and impact are generated.

  Thus, in the case of torque 3T, the rotational speed of the motor 2 can be increased in a short time, and a large backlash amount can be obtained from an early stage of backlash control, whereas in the case of torque T The amount of backlash can be increased with the output power of the motor 2 so as not to generate rattling noise or impact over a relatively long time.

  Therefore, at the start of the backlash control, a large backlash torque is output from the motor 2 to quickly increase the rotation speed of the motor 2, and then the backlash torque is reduced while maintaining the rotation speed of the motor 2. When the rotation angle of the motor 2 reaches the rotation angle θ target necessary for backlashing, the output power of the motor 2 is set to be smaller than the limit output power Plmt that generates a rattling noise or an impact (rotation of the motor 2). If the motor 2 is controlled so that the shape of the region sandwiched between the graph showing the change in speed and the horizontal axis thereof approaches a quadrangle), the necessary backlash can be carried out in the shortest time.

  FIG. 7 is a diagram illustrating temporal changes in motor output torque, rotation speed, and output power in the backlash control according to the first embodiment.

  In the backlash control according to the first embodiment, the motor 2 is controlled, and the largest backlash torque is output from the motor 2 in the first half of the backlash control. Thereby, the rotation speed of the motor 2 can be quickly raised at the start of the backlash control. In the second half of the backlash control, the backlash torque output from the motor 2 is gradually reduced. As a result, when the rotation angle of the motor 2 reaches the rotation angle θ target necessary for backlashing, the output power of the motor 2 can be made smaller than the limit output power Plmt that generates a rattling noise or an impact.

  As a result, compared to the backlash control shown in FIG. 6, the shape of the region sandwiched between the graph showing the temporal change in the rotational speed of the motor 2 and the horizontal axis of the graph approaches a quadrangle, which is necessary for backlashing. The rotation angle θtarget of the motor 2 can be obtained in a short time.

  Therefore, it is possible to reduce the time required for backlashing while suppressing the occurrence of rattling noise and impact due to backlashing of the power transmission system of the electric vehicle 1.

  The graph showing the time change of the backlash torque when the backlash torque is gradually reduced, because the shape of the region sandwiched between the graph showing the time change of the rotational speed of the motor 2 and the horizontal axis is close to a quadrangle, Exponential curve y = Aexp (−t / τ) (y: backlash torque, A: maximum value (peak value) of backlash torque, t: time, τ: time constant) or inversely proportional curve y = B / T (y: backlash torque, B: inverse proportionality constant, t: time).

  FIG. 8 is a diagram illustrating temporal changes in the output torque, rotation speed, and output power of the motor in the backlash control according to the second embodiment.

  In the backlash control shown in FIG. 8, the motor 2 is controlled, and from time 0 to time t1 when the backlash control is started, the magnitude in the direction corresponding to the shift range after the reverse range switching from the motor 2 is performed. The backlash torque of T1 is output. The amount of rattling torque T1 and the time during which the rattling torque is output (the time from time 0 to time t1) are such that the output power of the motor 2 from the time t0 to the time t1 has a rattling sound and an impact. Each is set in a range that does not exceed the limit output power Plmt to be generated. Thereafter, during the period from time t1 to time t2, the output of the backlashing torque from the motor 2 is stopped. Then, between time t2 and time t3, the backlash torque having a magnitude T2 smaller than the magnitude T1 is output from the motor 2. From time t3 to time t4, the output of the backlashing torque from the motor 2 is stopped. Thereafter, when the backlash torque having a magnitude T3 smaller than the magnitude T2 is output from the motor 2 between time t4 and time t5, the backlash control ends.

  The time from time 0 to time t1, the time from time t1 to time t2, the time from time t2 to time t3, the time from time t3 to time t4, and the time from time t4 to time t5 are all the same length Is set.

  In this way, in the backlash control shown in FIG. 8, the backlash torque is output from the motor 2 in a pulsed manner at a constant time interval over a fixed time. Then, at the initial stage of the backlash control, the maximum backlash torque is output from the motor 2, and then the backlash torque is reduced each time the backlash torque is output.

  Thereby, the rotation speed of the motor 2 can be raised at a stretch at the initial stage of the backlash control. As a result, when the elapsed time from the start of the backlash control is taken on the horizontal axis and the rotational speed of the motor 2 after the start of the backlash control is taken on the vertical axis, the graph shows the time change of the rotational speed of the motor 2 The shape of the region sandwiched between the horizontal axes of the graph approaches a quadrangle, and the rotation angle θtarget of the motor 2 necessary for backlashing can be obtained in a short time.

  Therefore, it is possible to reduce the time required for backlashing while suppressing the occurrence of rattling noise and impact due to backlashing of the power transmission system of the electric vehicle 1.

  In the backlash control shown in FIG. 7, since the backlash torque is continuously output from the motor 2, the rotation speed of the motor 2 increases as time elapses. For this reason, it is expected that the rotation speed of the motor 2 at the end of the backlash control will be a predetermined value or less, and the magnitude of the backlash torque at the initial stage of the backlash control must be determined. It is necessary to set a little smaller. Also, for ease of control of the backlashing torque, the on / off duty is determined and the backlashing torque is reduced as in the backlash control shown in FIG. It is more practical to change the pulse shape.

  FIG. 9 is a diagram showing temporal changes in motor output torque, rotation speed, and output power in the backlash control according to the third embodiment.

  In the backlash control shown in FIG. 9, the motor 2 is controlled, and from time 0 to time t1 when the backlash control is started, the magnitude in the direction corresponding to the shift range after the reverse range switching from the motor 2 is performed. A backlash torque of T4 is output. The amount of rattling torque T4 and the time during which the rattling torque is output (the time from time 0 to time t1) are such that the output power of the motor 2 during the period from time t0 to time t1 is affected by rattling noise and impact. Each is set in a range that does not exceed the limit output power Plmt to be generated. Also, the backlash torque magnitude T4 is larger than the backlash torque magnitude T1 in the backlash control shown in FIG. Thereafter, during the period from time t1 to time t2, the output of the backlashing torque from the motor 2 is stopped. And from time t2 to time t3, the backlash torque having a magnitude T2 smaller than the magnitude T4 is output from the motor 2. From time t3 to time t4, the output of the backlashing torque from the motor 2 is stopped. Thereafter, when the backlash torque having a magnitude T3 smaller than the magnitude T2 is output from the motor 2 between time t4 and time t5, the backlash control ends.

  The time from time t2 to time t3 is set to a time longer than the time from time 0 to time t1, and the time from time t4 to time t5 is set to a time longer than the time from time t2 to time t3. Has been. The time from time 0 to time t1, the time from time t2 to time t3, and the time from time t4 to time t5 are from time 0 to time t1, from time t2 to time t3, and from time t4, respectively. The output power of the motor 2 until time t5 is set in a range that does not exceed the limit output power Plmt that generates a rattling sound and an impact. The time from time t1 to time t2 and the time from time t3 to time t4 are set to the same length.

  As described above, in the backlash control shown in FIG. 9, the backlash torque is output from the motor 2 in pulses at regular time intervals. Then, at the initial stage of the backlash control, the maximum backlash torque is output from the motor 2, and then the backlash torque is reduced each time the backlash torque is output. The time for which the maximum backlash torque is output is set to the shortest time, and thereafter, every time the backlash torque is output, the time for which the backlash torque is output becomes longer.

  As a result, when the elapsed time from the start of the backlash control is taken on the horizontal axis and the rotational speed of the motor 2 after the start of the backlash control is taken on the vertical axis, the graph shows the time change of the rotational speed of the motor 2 The shape of the region sandwiched between the horizontal axes of the graph approaches a quadrangle, and the rotation angle θtarget of the motor 2 necessary for backlashing can be obtained in a short time.

  Therefore, it is possible to reduce the time required for backlashing while suppressing the occurrence of rattling noise and impact due to backlashing of the power transmission system of the electric vehicle 1.

  As mentioned above, although three embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the backlash control shown in FIGS. 8 and 9, it is assumed that the backlash torque output from the motor 2 is 0 from time t1 to time t2 and from time t3 to time t4. . However, the backlash torque smaller than the magnitude T may be output from the motor 2 from time t1 to time t2 and from time t3 to time t4.

  In addition, in the backlash control shown in FIG. 9, the magnitude T4 of the backlash torque output first from the motor 2 and the time during which the backlash torque is output (time from time 0 to time t1) It is assumed that the output power of the motor 2 between t0 and time t1 is set in a range that does not exceed the limit output power Plmt that generates a rattling sound and an impact. However, as long as it is a period until the gear teeth meshing with each other come into contact with each other, as shown in FIG. 10, the magnitude T4 of the backlashing torque and the time during which the backlashing torque is output (from time 0 to time t1). May be set so that the output power of the motor 2 from the time 0 to the time t1 exceeds the limit output power Plmt that generates a rattling sound and an impact. Furthermore, if it is a period until the teeth of the gears that mesh with each other come into contact with each other, the magnitude T2 of the backlashing torque and the time during which the backlashing torque is output (time from time t2 to time t3) are from time t2. The output power of the motor 2 until time t3 may be set so as to exceed the limit output power Plmt that generates a rattling sound and an impact.

  Furthermore, as shown in FIG. 11, the amplitude (magnitude) of the pulse-like rattling torque may be gradually reduced with the passage of time during the period in which the pulse-like rattling torque is being output. .

  Further, in the case where the backlash control is performed when the electric vehicle 1 is traveling at a fine vehicle speed (for example, 5 km / h or less), compared to the case where the backlash control is performed while the electric vehicle 1 is stopped. The magnitude of the backlashing torque and / or the time during which the backlashing torque is output may be set to a small value.

  That is, since the inertia of the gears on the rear wheels 3RL, 3RR side is greater than the inertia of the gears on the motor 2 side between the meshing gears, the reverse range switching is performed while the electric vehicle 1 is traveling at a fine vehicle speed. In this case, the backlash (gap) generated between the gears engaged with each other is small as compared with the case where the reverse range switching is performed while the electric vehicle 1 is stopped. Therefore, when reverse range switching is performed while the electric vehicle 1 is traveling at a fine vehicle speed, the motor required for backlashing is smaller than when reverse range switching is performed while the electric vehicle 1 is stopped. The rotation angle of 2 may be small. Therefore, in the case where the backlash control is performed when the electric vehicle 1 is traveling at a fine vehicle speed, the magnitude of the backlash torque is smaller than the case where the backlash control is performed while the electric vehicle 1 is stopped. The time for outputting the backlash torque may be set to a small value.

  Moreover, although the electric vehicle is taken up as an example of the electric vehicle 1, the present invention can also be applied to a hybrid car using an engine and a motor as drive sources.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Motor 11 Vehicle ECU (Control apparatus, reverse direction range switching permissive means, reverse direction range switching detection means, backlash control means)
21 Shift sensor (reverse direction range switching detection means)

Claims (2)

An electric vehicle backlash control device using at least a motor as a drive source,
Reverse range switching permission means for allowing reverse range switching in which the shift range is switched from one of the forward range and the reverse range through the neutral range to the other of the forward range and the reverse range;
Reverse direction range switching detecting means for detecting the reverse direction range switching by a shift operation;
In response to the detection of the reverse range switching by the reverse range switching detection means, the backlash control for outputting the backlash torque in the direction corresponding to the shift range after the reverse range switching from the motor for a predetermined time. Including backlash control means for
The backlash control device for an electric vehicle, wherein the backlash control means outputs a maximum backlash torque within the first half of the predetermined time, and continuously and gradually reduces the backlash torque from the maximum value. An electric vehicle backlash control device using at least a motor as a drive source,
Reverse range switching permission means for allowing reverse range switching in which the shift range is switched from one of the forward range and the reverse range through the neutral range to the other of the forward range and the reverse range;
Reverse direction range switching detecting means for detecting the reverse direction range switching by a shift operation;
In response to the detection of the reverse range switching by the reverse range switching detection means, the backlash control for outputting the backlash torque in the direction corresponding to the shift range after the reverse range switching from the motor for a predetermined time. Including backlash control means for
The backlash control means outputs a backlash torque in a pulse shape, the amplitude of the pulse backlash torque output at the beginning of the predetermined time is relatively large, and the finally output pulse backlash backlash An electric vehicle backlash control device that gradually reduces the amplitude of each pulse-shaped backlash torque so that the torque amplitude is relatively small.

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