JP7328087B2 - Control device for electric vehicle and electric vehicle - Google Patents

Description

Embodiments of the present invention relate to a control device for an electric vehicle and an electric vehicle.

A technique for coasting a vehicle when the vehicle is traveling at a high speed in order to improve fuel efficiency is known. For example, Patent Literature 1 describes a vehicle that prevents engine braking by disengaging the clutch when it is determined that the accelerator opening of the vehicle is constant.

Japanese Patent Application Publication No. 2015-525710

In a vehicle equipped with an engine, the engine always operates to rotate the input shaft of the transmission even during coasting, so the rotation of the input shaft operates the oil pump to supply lubricating oil to the bearings of the transmission. However, unlike an engine, an electric vehicle does not have the power to constantly rotate the input shaft. Feeding may not occur and bearing seizure may occur.

Therefore, it is required to prevent seizing of bearings during coasting.

SUMMARY In one aspect, a control device for an electric vehicle is provided that includes a motor that generates driving force for running and a transmission that is connected to the motor. A transmission includes an input shaft that rotates by receiving a driving force from a motor, an output shaft that is arranged parallel to the input shaft and transmits the rotation of the input shaft to drive wheels, and one of the input shaft and the output shaft. a plurality of fixed gears fixed to the shaft of the, a plurality of idle gears provided through bearings to the other shaft of the input shaft and the output shaft in a state of meshing with the plurality of fixed gears, and the other and a shift member engageable with a corresponding idler gear among a plurality of idler gears; and an oil pump that is operated by the rotation of the input shaft to supply lubricating oil to the bearings. The control device drives the motor to rotate the input shaft when the shift member is placed in a neutral position in which the shift member is not engaged with any of the idler gears while the electric vehicle is running.

In the above transmission, when the shift member is placed in the neutral position while the electric vehicle is running, rotation is transmitted from the driving wheels to the output shaft and the output shaft rotates. At this time, the idle gear rotates (idle) by the bearing, so the rotation of the output shaft is not transmitted to the input shaft. Thus, when the free rotation gear idles and does not rotate, the oil pump does not operate and the supply of lubricating oil to the bearings is delayed, which may cause seizure of the bearings. In contrast, according to the control device described above, when the shift member is placed in the neutral position while the electric vehicle is running, the motor is driven to rotate the input shaft, so lubricating oil is supplied to the bearings. can be done. Therefore, it is possible to prevent seizure of the bearings during coasting.

In one embodiment, the control device may move the position of the shift member to the neutral position when it is determined that the amount of change in accelerator opening within a predetermined period of time is less than a predetermined threshold. In this embodiment, the vehicle can be coasted by moving the position of the shift member to the neutral position. As a result, the energy efficiency (power consumption) of the electric vehicle can be improved.

In one embodiment, the controller may move the position of the shift member to the neutral position when it is determined that the amount of change in speed within a predetermined period of time is less than a predetermined threshold. In this embodiment, the vehicle can be coasted by moving the position of the shift member to the neutral position. As a result, the energy efficiency (power consumption) of the electric vehicle can be improved.

An electric vehicle according to one aspect includes a motor that is a power source, a transmission that is connected to the motor, and a control device that controls the operation of the motor. The transmission includes an input shaft that rotates by receiving the driving force of the motor, an output shaft that is arranged parallel to the input shaft and transmits the rotation of the input shaft to drive wheels, the input shaft and the a plurality of fixed gears fixed to one of the output shafts; and a plurality of fixed gears that are engaged with the plurality of fixed gears and provided to the other shaft of the input shaft and the output shaft via bearings. a plurality of idle gears, a shift member fixed to the other shaft and engageable with a corresponding idle gear among the plurality of idle gears, and a shift member operated by rotation of the input shaft to lubricate the bearing and an oil pump for supplying oil. The control device drives the motor to rotate the input shaft when the shift member is placed at a neutral position in which the shift member is not engaged with any of the idle gears during running.

As described above, according to the electric vehicle, seizure of the bearings during coasting can be prevented.

According to one aspect and various embodiments of the present invention, it is possible to prevent bearing seizure during coasting.

1 is a block diagram showing the functional configuration of a vehicle according to one embodiment; FIG. It is a longitudinal cross-sectional view of a transmission. 2 is a diagram schematically showing the configuration of a transmission; FIG. 4 is a flowchart showing the flow of processing by the control device; FIG. 4 is a cross-sectional view showing a lubricating oil supply route;

Various embodiments are described in detail below with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and redundant description of the same or corresponding parts is omitted.

FIG. 1 is a block diagram showing the functional configuration of a vehicle V according to one embodiment. A vehicle V shown in FIG. This vehicle V is an electric vehicle that runs by the driving force of the motor 2, and is, for example, a large vehicle such as a bus or a truck.

The motor 2 is a motor-generator having the functions of both an electric motor and a generator. When the vehicle V is running, the motor 2 generates a driving force for running from electric power supplied from the battery 8 via the inverter 6 . When the vehicle V decelerates, the motor 2 generates regenerative torque to generate regenerative electric power. Regenerated electric power generated by the motor 2 is supplied to the battery 8 via the inverter 6 .

The battery 8 is, for example, various secondary batteries such as a lithium ion battery. The battery 8 outputs electric power for driving the motor 2 when the vehicle V is running, and receives regenerative electric power generated by the motor 2 when the vehicle V decelerates to be charged.

Inverter 6 is electrically connected to motor 2 and battery 8 . When the vehicle V is running, the inverter 6 converts the DC power output from the battery 8 into AC power and supplies the AC power to the motor 2 in accordance with the power required by the motor 2 . During regenerative control, the inverter 6 converts the regenerated electric power generated by the motor 2 into DC electric power to charge the battery 8 . The inverter 6 adjusts the regenerative electric power generated by the motor 2 based on the state of charge (SOC) of the battery 8, temperature, and the like.

The transmission 4 transmits the driving force generated by the motor 2 to the driving wheels 20 of the vehicle V. As shown in FIG. An input shaft (one shaft) 21 of the transmission 4 is connected to the output shaft of the motor 2 via, for example, a clutch device (see FIG. 2). An output shaft (the other shaft) 31 of the transmission 4 is connected to the left and right driving wheels 20 via the propeller shaft 14 , the differential gear 16 and the drive shaft 18 . Details of the transmission 4 will be described later.

The sensor unit 12 has a plurality of sensors for acquiring travel information of the vehicle V. FIG. In one example, the sensor unit 12 has a vehicle speed sensor, an accelerator pedal sensor, a battery temperature sensor, and an SOC sensor.

The vehicle speed sensor is provided on the drive shaft 18 of the vehicle V, for example, and obtains the running speed of the vehicle V from the rotation speed of the drive wheels 20 . The accelerator pedal sensor is provided on the accelerator pedal of the vehicle V and acquires the accelerator opening from the amount of depression of the accelerator pedal. A battery temperature sensor acquires the temperature of the battery 8 . The SOC sensor acquires the charging rate of the battery 8 .

The sensor unit 12 may further include an inverter temperature sensor that acquires the temperature of the inverter 6, a slope sensor that acquires the slope rate of the travel road, a motor temperature sensor that acquires the temperature of the motor 2, and the like. The sensor unit 12 outputs information acquired by these multiple sensors to the control device 10 .

The control device 10 has a function of controlling the operation of the vehicle V as a whole. The control device 10 is an electronic control unit having a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], a CAN [Controller Area Network] communication circuit, and the like. The control device 10 implements various functions by, for example, loading programs stored in the ROM into the RAM and executing the programs loaded into the RAM by the CPU. The control device 10 is communicably connected to the motor 2, the transmission 4, the inverter 6, and the sensor section 12. As shown in FIG. The control device 10 acquires information indicating the speed of the vehicle V, the accelerator opening, the battery temperature, and the charging rate of the battery 8 from the sensor unit 12, and supplies the information from the inverter 6 to the motor 2 based on the acquired information. Adjust power.

Next, details of the transmission 4 will be described with reference to FIGS. 2 and 3. FIG. FIG. 2 is a longitudinal sectional view of the transmission 4, and FIG. 3 is a diagram schematically showing the construction of the transmission 4. As shown in FIG. The transmission 4 is a manual electric vehicle transmission provided behind the motor 2 and has a function of transmitting the driving force generated by the motor 2 to the driving wheels 20 of the vehicle V. As shown in FIG.

As shown in FIGS. 2 and 3 , the transmission 4 has an input shaft 21 , a fixed gear 23 , a fixed gear 25 , an output shaft 31 , an idle gear 33 , an idle gear 35 and a shift mechanism 37 . Input shaft 21 , fixed gear 23 , fixed gear 25 , output shaft 31 , idle gear 33 , idle gear 35 and shift mechanism 37 are housed inside transmission case 28 .

The input shaft 21 is rotatably supported by a pair of bearings 27 within the transmission case 28 . The input shaft 21 is connected to the output shaft of the motor 2 that is the power source of the vehicle V, and rotates by receiving the driving force generated by the motor 2 .

A fixed gear 23 and a fixed gear 25 (a plurality of fixed gears) having different numbers of teeth are fixed to the input shaft 21 . The fixed gear 23 and the fixed gear 25 are integrally formed with the input shaft 21 and rotate together with the input shaft 21 upon receiving driving force from the motor 2 .

The output shaft 31 is rotatably supported by a pair of bearings 39 within the transmission case 28 . The output shaft 31 is spaced apart from the input shaft 21 and arranged parallel to the input shaft 21 . Output shaft 31 receives the rotational force of input shaft 21 and transmits the rotational force to driving wheels 20 of vehicle V via drive shaft 18 .

The output shaft 31 is provided with an idle gear 33 and an idle gear 35 (a plurality of idle gears) having different numbers of teeth. These idle gears 33 and 35 are rotatably supported with respect to the output shaft 31 via needle bearings 40 coaxially provided on the output shaft 31 . Therefore, the idle gear 33 and the idle gear 35 are provided so as to be able to idle (idle) with respect to the output shaft 31 .

The idle gears 33 and 35 mesh with the fixed gears 23 and 25, respectively. The idle gear 33 and the fixed gear 23 constitute a first gear pair G1, and the idle gear 35 and the fixed gear 25 constitute a second gear pair G2. In the example shown in FIG. 2, the first gear pair G1 and the second gear pair G2 have different gear ratios.

An oil pump 42 is provided at the end of the input shaft 21 opposite to the motor 2 . Oil pump 42 is configured to be operated by rotation of input shaft 21 . When the input shaft 21 is rotated, the oil pump 42 sucks lubricating oil stored in an oil pan (not shown) and pumps it to the pair of bearings 27 and the needle bearings 40 of the transmission 4 . The amount of lubricating oil supplied from the oil pump 42 changes according to the rotational speed of the input shaft 21 .

An oil passage 21p and an oil passage 31p through which lubricating oil discharged from the oil pump 42 flows are formed inside the input shaft 21 and the output shaft 31, respectively. The oil passage 21 p extends from the discharge port of the oil pump 42 through the central axis of the input shaft 21 to the pair of bearings 27 . The oil passage 31p extends from the discharge port of the oil pump 42 through the central axis of the output shaft 31 to the needle bearing 40 . Therefore, the lubricating oil discharged from the oil pump 42 by the rotation of the input shaft 21 is supplied to the pair of bearings 27 and needle bearings 40 .

The shift mechanism 37 is provided between the idle gear 33 and the idle gear 35 of the output shaft 31 . As shown in FIG. 3, the shift mechanism 37 has a hub 37a connected to the output shaft 31 so as to be rotatable together with the output shaft 31, and a sleeve 37b connected to the hub 37a. . The sleeve 37b is a shift member of one embodiment, is fixed to the output shaft 31 via the hub 37a, and is configured to be engageable with one of the idle gears 33 and 35. .

A shift fork 37c is connected to the sleeve 37b. The shift fork 37 c slides in accordance with a gear ratio specified by the shift lever of the vehicle V, and moves the sleeve 37 b along the axial direction of the output shaft 31 .

Specifically, when the first gear ratio is specified by the shift lever, the shift fork 37c moves the sleeve 37b toward the idle gear 33 and engages the spline 33s of the idle gear 33 . As a result, the output shaft 31 is connected to the idle gear 33, and the input shaft 21 and the output shaft 31 are connected via the first gear pair G1. On the other hand, when the second gear ratio is specified by the shift lever, the shift fork 37c moves the sleeve 37b toward the idler gear 35 and engages the spline 35s of the idler gear 35 . As a result, the output shaft 31 is connected to the idle gear 35, and the input shaft 21 and the output shaft 31 are connected via the second gear pair G2.

As described above, when the sleeve 37b is engaged with the idle gear 33 or the idle gear 35, the driving force transmitted from the motor 2 to the input shaft 21 is transmitted through the output shaft 31 and the drive shaft 18. is transmitted to the driving wheels 20 to drive the vehicle V. On the other hand, during deceleration of the vehicle V, the rotational force of the driving wheels 20 is transmitted to the motor 2 via the output shaft 31 and the input shaft 21, and the regenerative torque of the motor 2 generates regenerative electric power.

Further, when neutral is specified by the shift lever, the sleeve 37b is moved to a position away from the idle gear 33 and the idle gear 35 by the shift fork 37c. That is, the sleeve 37b is arranged at a neutral position where it does not engage with either the idle gear 33 or the idle gear 35, as shown in FIG. When the sleeve 37b is located at the neutral position, the connection between the output shaft 31 and the free gears 33, 35 is released, and power is no longer transmitted between the input shaft 21 and the output shaft 31. .

When the sleeve 37b is placed in the neutral position while the vehicle V is traveling, the connection between the input shaft 21 and the output shaft 31 is released, and the vehicle V coasts. At this time, the rotational force of the output shaft 31 is not transmitted to the motor 2, and regenerative braking is not performed.

Next, the control device 10 will be described in detail. The control device 10 controls the operation of the motor 2 during coasting of the vehicle V so that the needle bearing 40 is not seized. FIG. 4 is a flowchart showing the processing flow of the control device 10. As shown in FIG. The control device 10 repeatedly executes a process described later at a predetermined cycle. In the following description, it is assumed that the vehicle V is running with the input shaft 21 and the output shaft 31 connected to each other via the first gear pair G1 at the start of the process.

As shown in FIG. 4, the control device 10 first acquires information indicating the charging rate of the battery 8 from the SOC sensor of the sensor unit 12, and determines whether or not the acquired charging rate is equal to or higher than a predetermined threshold (step ST1). If the charging rate of the battery 8 is less than a predetermined threshold, it is considered necessary to charge the battery 8 with regenerated power. The process is terminated while maintaining the connection of .

On the other hand, when the charging rate is equal to or higher than the predetermined threshold, control device 10 determines whether or not vehicle V is traveling at a constant speed (step ST2). In step ST2, the control device 10 acquires the accelerator opening from the accelerator pedal sensor of the sensor unit 12, and if it is determined that the amount of change in the accelerator opening within a predetermined period is smaller than a predetermined threshold value, the constant speed Determine that you are running. Note that the control device 10 acquires the speed of the vehicle V from the vehicle speed sensor of the sensor unit 12, and when it is determined that the amount of change in the speed of the vehicle V within a predetermined period is smaller than a predetermined threshold value, the constant speed running is performed. It may be determined that

When it is determined in step ST2 that the vehicle V is not traveling at a constant speed, the control device 10 terminates the series of processes. On the other hand, when it is determined that the vehicle V is traveling at a constant speed, the controller 10 controls the shift fork 37c so that the sleeve 37b moves to the neutral position where it does not engage with any of the idle gears 33 and 35. to control. At this time, the position of the shift lever of the vehicle V may be maintained.

By disposing the sleeve 37b at the neutral position, the connection between the output shaft 31 and the idle gears 33, 35 is released, and the output shaft 31 idles with respect to the idle gears 33, 35, causing the input shaft 21 to rotate. and the output shaft 31. As a result, the regenerative braking by the motor 2 ceases to act, and the vehicle V performs inertia running at a constant speed due to inertia without relying on power from the outside.

Next, the control device 10 controls the inverter 6 to supply electric power to the motor 2 and drive the motor 2 to rotate the input shaft 21 . When the input shaft 21 rotates, the oil pump 42 operates to discharge lubricating oil. As shown in FIG. 5, the lubricating oil discharged from the oil pump 42 is supplied to the pair of bearings 27 through the oil passage 21p formed in the input shaft 21, and is supplied to the oil passage formed in the output shaft 31. 31p to the needle bearing 40. This lubricating oil prevents seizure of the needle bearing 40 when the vehicle V is coasting. After that, the control device 10 terminates the series of processes.

As described above, when the sleeve 37b is in the neutral position while the vehicle V is running, the rotation is transmitted from the driving wheels 20 to the output shaft 31 and the output shaft 31 rotates. At this time, the output shaft 31 idles (idles) with respect to the idle gears 33 and 35 by the needle bearing 40 , so the rotation of the output shaft 31 is not transmitted to the input shaft 21 . Thus, when the output shaft 31 idles with respect to the idle gear and the input shaft 21 does not rotate, the oil pump 42 does not operate and the supply of lubricating oil to the needle bearing 40 is interrupted. burn-in may occur. On the other hand, the control device 10 drives the motor 2 to rotate the input shaft 21 during coasting when the sleeve 37b is located at the neutral position. can supply. Therefore, seizure of the needle bearing 40 during coasting can be prevented.

Further, when it is determined that the vehicle V is traveling at a constant speed, the control device 10 causes the vehicle V to coast by moving the position of the sleeve 37b to the neutral position. By coasting the vehicle V, the energy efficiency (electricity consumption) of the vehicle V can be improved. Further, the control device 10 coasts the vehicle V when the charging rate of the battery 8 is high, and applies regenerative braking when the charging rate of the battery 8 is low. can be improved.

Although the control device 10 for an electric vehicle according to various embodiments has been described above, it is possible to configure various modifications without being limited to the above-described embodiments without changing the gist of the invention.

For example, in the above embodiment, the fixed gears 23 and 25 are fixed to the input shaft 21, and the idle gears 33 and 35 are rotatably supported by the output shaft 31 through the needle bearings 40. The fixed gears 23 and 25 may be fixed to the input shaft 21, and the idle gears 33 and 35 may be rotatably supported by the input shaft 21 via needle bearings 40. In this case, the sleeve 37b is fixed to the input shaft 21 and configured to be able to engage with the idler gear among the idler gears 33 and 35 corresponding to the operation of the shift lever.

In this embodiment as well, when the sleeve 37b is placed at the neutral position while the vehicle V is running, the idle gears 33 and 35 rotate (idle) with respect to the input shaft 21 by the needle bearing 40. Rotation of shaft 31 is not transmitted to input shaft 21 . Thus, when the idle gears 33 and 35 idle with respect to the input shaft 21 and the input shaft 21 does not rotate, the oil pump 42 does not operate and the supply of lubricating oil to the needle bearing 40 is interrupted. Seizure may occur in the needle bearing 40 . Even in this case, the control device 10 operates the oil pump 42 to rotate the needle bearing 40 by driving the motor 2 to rotate the input shaft 21 during coasting when the sleeve 37b is located at the neutral position. Lubricating oil can be supplied.

Although the needle bearing 40 is provided between the output shaft 31 and the idle gears 33 and 35 in the above embodiment, the output shaft 31 can idle with respect to the idle gears 33 and 35. If so, any kind of bearings such as ball bearings and roller bearings can be used as the bearings between the output shaft 31 and the idle gears 33 and 35 .

In addition, in the embodiment shown in FIG. 4, the vehicle V is coasting when the battery charging rate is greater than a predetermined threshold. If it is determined that the vehicle V is running at high speed, the vehicle V may be controlled to coast.

In the above embodiment, the controller 10 drives the motor 2 to rotate the input shaft 21 after the sleeve 37b is moved to the neutral position. When actuated to the position, controller 10 may drive motor 2 to rotate input shaft 21 . Even in this case, seizure of the needle bearing 40 can be prevented.

Further, in the above embodiment, the fixed gears 23, 25 are formed integrally with the input shaft. may be configured.

2 Motor 4 Transmission 10 Control device 20 Drive wheel 21 Input shaft 23, 25 Fixed gear 31 Output shaft 33, 35 Idle gear 37b Sleeve (shift member ), 42... oil pump, V... vehicle.

Claims (4)

A control device for an electric vehicle having a motor for generating driving force for running and a transmission connected to the motor,
the transmission is
an input shaft that rotates by receiving a driving force from the motor;
an output shaft arranged parallel to the input shaft and transmitting rotation of the input shaft to drive wheels;
a plurality of fixed gears fixed to one of the input shaft and the output shaft;
a plurality of idle gears provided via bearings to the other shaft of the input shaft and the output shaft in a state of meshing with the plurality of fixed gears;
a shift member fixed to the other shaft and engageable with a corresponding idle gear among the plurality of idle gears;
an oil pump operated by the rotation of the input shaft to supply lubricating oil to the bearing;
has
The control device drives the motor to rotate the input shaft when the shift member is placed in a neutral position where the shift member is not engaged with any of the plurality of idler gears while the electric vehicle is running. ,Control device. 2. The control device according to claim 1, wherein said control device moves said shift member to said neutral position when it is determined that an amount of change in accelerator opening within a predetermined period is smaller than a predetermined threshold. The control according to claim 1, wherein the control device moves the shift member to the neutral position when it is determined that the amount of change in speed of the electric vehicle within a predetermined period is smaller than a predetermined threshold. Device. a motor as a power source;
a transmission connected to the motor;
a control device that controls the operation of the motor;
with
the transmission is
an input shaft that rotates by receiving the driving force of the motor;
an output shaft arranged parallel to the input shaft and transmitting rotation of the input shaft to drive wheels;
a plurality of fixed gears fixed to one of the input shaft and the output shaft;
a plurality of idle gears provided via bearings to the other shaft of the input shaft and the output shaft in a state of meshing with the plurality of fixed gears;
a shift member fixed to the other shaft and engageable with a corresponding idle gear among the plurality of idle gears;
an oil pump operated by the rotation of the input shaft to supply lubricating oil to the bearing;
has
The control device drives the motor to rotate the input shaft when the shift member is placed in a neutral position in which the shift member is not engaged with any of the plurality of idle gears during running. .

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