WO2012086223A1

WO2012086223A1 - Electric vehicle

Info

Publication number: WO2012086223A1
Application number: PCT/JP2011/057840
Authority: WO
Inventors: 信義武藤; 忠彦加藤; 和利村上
Original assignee: 株式会社ユニバンス
Priority date: 2010-12-24
Filing date: 2011-03-29
Publication date: 2012-06-28
Also published as: JP2012135172A

Abstract

An electric vehicle (1) is provided with: a motor (3f) for the front wheels, transmitting braking and driving forces to the left and right front wheels; a motor (3r) for the rear wheels, transmitting braking and driving forces to the left and right rear wheels; an inverter (8f) for the front wheels, driving the motor (3f) for the front wheels; and an inverter (8r) for the rear wheels, driving the motor (3r) for the rear wheels. The motor (3f) for the front wheels and the motor (3r) for the rear wheels are arranged line-symmetrically or point-symmetrically with respect to the center (25a) of the vehicle body. The inverter (8f) for the front wheels and the inverter (8r) for the rear wheels are disposed so as to be line-symmetrical when the motor (3f) for the front wheels and the motor (3r) for the rear wheels are disposed line-symmetrically and so as to be point-symmetrical when the motors (3f) for the front wheels and the motors (3r) for the rear wheels are disposed point-symmetrically.

Description

Electric car

The present invention relates to an electric vehicle in which front and rear wheels are independently driven by two electric motors.

Conventionally, an electric vehicle has been proposed in which the center of gravity is positioned on the center line of the vehicle body when the driver gets on (see, for example, Patent Document 1).

In this electric vehicle, the driver's seat is arranged so as to be shifted from the center line of the vehicle body in order to improve ease of getting on and off, and the center of gravity of the collective battery composed of a plurality of individual batteries is offset from the center line of the vehicle body in the direction opposite to the driver's seat. The electric motor is arranged near the rear of the driver's seat.

JP-A-9-309343

However, according to the conventional electric vehicle, since the electric motor is arranged at a position close to the driver's seat, vibrations and motor sounds of the electric motor are easily transmitted to the driver, and it is difficult to ensure comfortable operation performance.

Therefore, an object of the present invention is to provide an electric vehicle that ensures a comfortable operation performance and is excellent in running stability.

In one aspect of the present invention, in order to solve the above problems, a first electric motor that transmits braking / driving force to the left and right wheels on the front wheel side and a second electric motor that transmits braking / driving force to the left and right wheels on the rear wheel side are provided. A motor, a first inverter that drives the first electric motor, and a second inverter that drives the second electric motor, wherein the first and second electric motors are located at the center of the vehicle body. The first and second inverters are arranged in line symmetry when the first and second electric motors are arranged in line symmetry, and the first and second inverters are arranged in line symmetry. When the second electric motor is arranged point-symmetrically, an electric vehicle arranged point-symmetrically is provided.

According to the above configuration, by arranging the first and second electric motors and the first and second inverters as described above, the center of gravity of the entire electric vehicle is located substantially at the center of the vehicle body and is stable. Driving is possible. Here, by separating the first electric motor for the front wheels from the driver's seat, vibrations and motor sounds generated from the first electric motor are hardly transmitted to the driver.

According to the present invention, it is possible to ensure comfortable operation performance and excellent running stability.

FIG. 1 is a block diagram conceptually showing the structure of an electric vehicle according to an embodiment of the present invention. FIG. 2A is a cross-sectional view of the front wiring portion for explaining the structure of the H-shaped wiring portion. FIG. 2B is a cross-sectional view of the rear wiring portion for explaining the structure of the H-shaped wiring portion. FIG. 2C is a cross-sectional view of the central wiring portion for explaining the structure of the H-shaped wiring portion. FIG. 3 is a block diagram functionally showing the controller. FIG. 4 is a diagram showing the relationship between the driving force and braking force and the slip ratio. FIG. 5 is a diagram for explaining a method of distributing the braking force to the front wheels and the rear wheels.

FIG. 1 is a block diagram conceptually showing the configuration of an electric vehicle according to an embodiment of the present invention. In the figure, additional symbols f, r, fr, fl, rr, rl indicating whether the position of the component is the front wheel side or the rear wheel side, the right side or the left side of the front wheel side, the right side or the left side of the rear wheel side. Is attached to the component. Further, when it is not necessary to particularly distinguish the positions of the constituent elements, the words “for front wheels” and “for rear wheels” indicating the additional symbols and positions may be omitted.

(Overall configuration)
The electric vehicle 1 includes a front wheel motor 3f as a first electric motor that drives front wheels 2fr and 2fl via a front wheel differential 4f and axles 5fr and 5fl as a first differential, and a rear wheel. 2rr and 2rl as a second differential device, a rear wheel differential device 4r and a rear wheel motor 3r as a second electric motor driven via the axles 5rr and 5rl, and a drive energy source for the electric vehicle 1 As a main power supply unit 6, a low-voltage battery 7 for an electronic device of the electric vehicle 1, a front-wheel inverter 8 f and a rear wheel for converting electric power from the main power supply unit 6 into AC power and supplying the

motor

3 f and 3 r If the inverter 8r, the driver's seat 9 arranged on either the left or right side of the center line Lc of the vehicle body 25 (right side in the present embodiment), and a signal corresponding to the target torque are output to the

inverters

8f and 8r. In addition, the controller 10 that independently controls the braking / driving force of the front wheel motor 3f and the rear wheel motor 3r, the radiator 11 that cools the

motors

3f, 3r, and the like, and the rotation of the axles 5fr, 5fl, 5rr, and 5rl are braked. A front-rear wheel independent drive type electric vehicle including a mechanical brake 18fr, 18fl, 18rr, 18rl and a pressure adjusting unit 12 that supplies fluid pressure to the mechanical brakes 18fr, 18fl, 18rr, 18rl to generate friction braking. is there.

In addition, the electric vehicle 1 includes the operating means such as an accelerator pedal, a brake pedal, and a shift lever for designating forward or reverse, and the rotation speeds of the front wheel motor 3f and the rear wheel motor 3r. Temperatures for detecting the temperatures of the

encoders

16f and 16r for detecting, the two cameras 20fr and 20rl provided on the front side of the vehicle body 25, the camera 21 provided on the rear side of the vehicle body 25, and the

motors

3f and 3r, respectively.

Sensors

27f, 27r and wheel speed sensors 28fr, 28fl, 28rr, 28rl for detecting the rotation speed of the wheel 2 are provided.

In this specification, “braking / driving force” may mean both braking force for decelerating the vehicle and driving force for accelerating the vehicle, or only one of them.

(Power supply system)
The main power supply unit 6 includes a pair of batteries 60r and 60l connected in parallel to each other, and a pair of smoothing capacitors (for example, 6500 μF) 61r and 61l connected in parallel to the respective output sides of the high voltage batteries 60r and 60l. Prepare.

The high voltage batteries 60r and 60l are high voltage batteries that can output electric power for driving the front wheel motor 3f and the rear wheel motor 3r. In addition to the battery, a primary battery such as a dry battery, a fuel cell, or the like may be used as a drive energy source for the electric vehicle 1.

The pair of high-voltage batteries 60r and 60l are configured to be electrically connectable to a terminal portion provided in a central wiring portion 132 of the H-shaped wiring portion 13 described later by a bus bar 62. The terminal portion is connected to the power cable 142. The replacement of the high voltage batteries 60r and 60l can be easily performed by attaching and detaching the bus bar 62 from the side of the vehicle body 25.

As the front wheel motor 3f and the rear wheel motor 3r, various motors such as a synchronous motor and an induction motor can be used. The rotation of the motor 3 is transmitted to the axle 5 via the differential device 4 on each of the front wheel side and the rear wheel side. The axle 5 rotates integrally with the wheel 2. That is, the electric vehicle 1 has two torque generation sources corresponding to the front wheels 2fr and 2fl and the rear wheels 2rr and rl so that the front wheels 2fr and 2fl and the rear wheels 2rr and rl can be controlled independently of each other.

The inverter 8 converts the power from the high voltage battery 60 into AC power, and outputs a current corresponding to a signal from the controller 10 to the motor 3 to drive the motor 3. Further, the inverter 8 converts the AC power generated by the motor 3 into DC power and charges the high voltage battery 60 via the capacitor 61.

The low voltage battery 7 converts a high DC voltage of the main power supply unit 6 by a DC / DC converter (not shown), converts it to a DC low voltage (for example, 12 V), and outputs it. As the low voltage battery 7, for example, an electric double layer capacitor (EDLC: Electric Double Layer Capacitor) can be used.

The controller 10 detects current sensors 15a to 15c, which will be described later, respectively, which detect the current of the primary winding of the front wheel motor 3f, and current sensors 17a, which will be described later, which detect the current of the primary winding of the rear wheel motor 3r. The current detection signal from 17c is received, and a signal corresponding to the target torque is output to

inverters

8f and 8r.

The

differential devices

4f and 4r are, for example, so-called a pair of side gears connected to the axles 5fr, 5fl, 5rr, and 5rl, a plurality of pinion gears that mesh with the pair of side gears, and a differential case that supports the plurality of pinion gears so as to be able to rotate. Open differential can be used. The braking / driving force of the front wheel motor 3f is distributed to the right front wheel 2fr and the left front wheel 2fl by the front wheel differential 4f. The braking / driving force of the rear wheel motor 3r is distributed to the right rear wheel 2rr and the left rear wheel 2rl by the rear wheel differential 4r. The differential device includes a mechanism capable of controlling the distribution ratio of braking / driving force to the front wheel axles 5fr, 5fl or the distribution ratio of braking / driving force to the rear wheel axles 5rr, 5rl by the controller 10. May be good.

(Brake system)
In the electric vehicle 1, an electric brake and a mechanical brake are used in combination. That is, in the electric vehicle 1, a braking force can be generated by the motor 3 as a drive source. The electric brake is, for example, a power generation brake that converts braking energy into heat energy, and a regenerative brake that regenerates electricity generated by braking. In the present embodiment, a regenerative brake is mainly used, but a power generation brake may be used in a low speed region. The regenerative brake regenerates the electric power generated by the motor 3 to the high voltage batteries 60r and 60l via the capacitors 61r and 61l, thereby generating a braking force.

The mechanical brake 18 is, for example, a drum brake or a disk brake, and presses a brake shoe against a member to be braked by a pressurized liquid from the pressure adjustment unit 12 to obtain friction braking by a friction force. The operation of the mechanical brake 18 is controlled independently for each wheel 2 by the controller 10. The brake shoe may be pressed against the member to be braked by an actuator such as a motor.

The pressure adjustment unit 12 is configured to be able to apply a different braking force to each mechanical brake 18 by distributing pressurized liquid to the mechanical brake 18 by a signal from the controller 10. The pressure adjusting unit 12 and the mechanical brake 18 constitute a friction brake mechanism.

(Imaging system)
The front cameras 20 fr and 20 fl capture the road surface on the front side of the electric vehicle 1 and output the captured image to the controller 10. The controller 10 detects a change in the road surface based on the images acquired from the cameras 20fr and 20fl, and executes processing related to braking / driving. The imaging regions of the front cameras 20fr and 20fl overlap at least partially with each other. The cameras 20fr and 20fl are constituted by, for example, a CCD (Charge Coupled Device) camera.

The rear camera 21 captures the road surface behind the electric vehicle 1 and outputs the captured image to the controller 10. The controller 10 detects a change in the road surface based on the image acquired from the camera 21 and executes processing related to braking / driving. The camera 21 is constituted by a CCD camera, for example.

(Arrangement of each part)
In the electric vehicle 1, when a driver (for example, a weight of 75 kg) gets on the driver's seat, the entire center of gravity G of the electric vehicle 1 is substantially positioned at the center 25 a of the vehicle body 25 (for example, within 10 cm or 20 cm from the center 25 a). As described above, the positions of the parts constituting the electric vehicle 1, for example, the parts constituting the front wheel and rear wheel drive systems are determined. That is, the front wheel motor 3f and the rear wheel motor 3r are arranged line-symmetrically or point-symmetrically with respect to the center 25a of the vehicle body 25, and the front wheel inverter 8f and the rear wheel inverter 8r include the front wheel motor 3f and the rear wheel. When the front motor 3r is arranged line-symmetrically, it is arranged line-symmetrically, and when the front wheel motor 3f and rear wheel motor 3r are arranged point-symmetrically, they are arranged point-symmetrically. In the present embodiment, the front wheel motor 3f and the rear wheel motor 3r are arranged symmetrically with respect to the center 25a of the vehicle body 25, and the front wheel inverter 8f and the rear wheel inverter 8r are arranged with respect to the center 25a of the vehicle body 25. Are arranged symmetrically.

Further, the front wheel motor 3f, the rear wheel motor 3r, the front wheel inverter 8f, and the rear wheel inverter 8r pass through the center 25a of the vehicle body 25 when they are arranged in line contrast or point contrast with respect to the center 25a of the vehicle body 25. An electric vehicle including a front wheel and a rear wheel drive system including a radiator 11, a controller 10, and a pair of high-voltage batteries 60r and 60l so as to cancel out moments about the axes (lateral x-axis, vertical y-axis) 1 may be positioned substantially at the center 25a of the vehicle body 25.

In addition, each component constituting the electric vehicle 1 may be arranged as follows. That is, the front wheel motor 3 f is disposed in front of the center 25 a of the vehicle body 25 and on the side opposite to the driver seat 9. The rear wheel motor 3r is arranged in a point contrast position with respect to the front wheel motor 3f. Further, the front wheel inverter 8f is disposed in front of the center 25a of the vehicle body 25 and on the driver's seat 9 side. The rear wheel inverter 8r is arranged in a point contrast position with respect to the front wheel inverter 8f. The pair of high-voltage batteries 60f and 60r and the pair of smoothing capacitors 61f and 61r constituting the main power supply unit 6 are arranged at positions symmetrical with respect to the center line Lc. Further, the front wheel motor 3f, the front wheel inverter 8f, the radiator 11, the controller 10, the low voltage battery 7 and the pressure adjustment unit 12 are disposed in front of the left and right wheels 2fr and 2fl on the front wheel side.

The arrangement of the parts constituting the electric vehicle 1 does not need to consider the weight of the driver, and considers the weight of the driver (for example, 75 kg) and the passenger who rides on the passenger seat (for example, 75 kg). May be. Further, the electric vehicle 1 is configured such that the center of gravity of the entire electric vehicle moves to the center 25a of the vehicle body 25 when a driver having a predetermined weight gets on the driver's seat than when the driver does not get on. Parts may be placed.

If the weights of the front wheel motor 3f, the rear wheel motor 3r, the front wheel inverter 8f, and the rear wheel inverter 8r are W3f, W3r, W8f, and W8r, respectively, these relationships are as follows in the present embodiment. .
W3r>W3f>W8r> W8f
Note that W3r = W3f>W8r> W8f or W3f>W3r>W8f> W8r may be used.

(Structure of H-type wiring part)
Cables to the components and the like arranged as described above are wired using the H-shaped wiring portion 13. The H-shaped wiring portion 13 includes a front wiring portion 130 provided along the front axles 5fr and 5fl, a rear wiring portion 131 provided along the rear axles 5rr and 5rl, and the center of the front wiring portion 130. The central wiring part 132 is connected to the central part of the rear wiring part 131. Details of the H-type wiring portion 13 will be described with reference to the drawings.

2A and 2B are diagrams for explaining the structure of the H-shaped wiring portion 13, where FIG. 2A is a cross-sectional view of the front wiring portion 130, FIG. 2B is a cross-sectional view of the rear wiring portion 131, and FIG. FIG. The H-shaped wiring part 13 is covered with an upper wall 13a, a lower wall 13b,

side walls

13c and 13d, and the interior is partitioned by a partition wall 13e.

As shown in FIG. 2A, the upper part of the partition wall 13e of the front wiring part 130 is a signal cable wiring region 130a in which the signal cable 141 is accommodated, and the lower part of the partition wall 13e is accommodated in the power cable 142. This is a power cable wiring region 130b.

As shown in FIG. 2B, the upper part of the partition wall 13e of the rear wiring part 131 is a signal cable wiring region 131a in which the signal cable 141 is accommodated, and the power cable 142 is accommodated in the lower part of the partition wall 13e. This is a power cable wiring region 131b.

As shown in FIG. 2C, the upper stage of the partition wall 13e of the central wiring part 132 is a signal cable wiring area 132a in which the signal cable 141 is accommodated, and the lower stage of the partition wall 13e is accommodated in the power cable 142. This is a power cable wiring region 132b. The signal cable wiring region 132a is divided into _two signal cable wiring regions 132a ₁ and 132a ₂ by a partition wall 13f.

The upper wall 13a, the lower wall 13b, the

side walls

13c and 13d, and the

partition walls

13e and 13f are made of a metal such as aluminum, copper, and stainless steel. By partitioning the signal cable 141 and the power cable 142 by the partition wall 13e, it is possible to prevent noise from the power cable 142 from being mixed into the signal transmitted by the signal cable 141.

A signal cable 141 and a power cable 142 from components such as a front wheel inverter 8f, a mechanical brake 18fr, and a wheel speed sensor 28fr located on the right front side with respect to the center 25a of the vehicle body 25 are a front wiring portion 130, a central wiring portion 132, and the like. It is connected to other parts via.

A signal cable 141 and a power cable from components such as a front wheel motor 3f, an encoder 16f, current sensors 15a to 15c, a mechanical brake 18fl, a temperature sensor 27f, and a wheel speed sensor 28fl located on the left front side with respect to the center 25a of the vehicle body 25. 142 is connected to other components via the front wiring portion 130, the central wiring portion 132, and the like.

A signal cable 141 and a power cable 142 from components such as a rear wheel inverter 8r, a mechanical brake 18rl, and a wheel speed sensor 28rl located on the left rear side with respect to the center 25a of the vehicle body 25 are a rear wiring portion 131 and a central wiring portion 132. Etc. to be connected to other parts.

A signal cable 141 and power from components such as a rear wheel motor 3r, an encoder 16r, current sensors 17a to 17c, a mechanical brake 18rr, a temperature sensor 27r, a wheel speed sensor 28rr, etc., located on the right rear side with respect to the center 25a of the vehicle body 25. The cable 142 is connected to other components via the rear wiring part 131, the central wiring part 132, and the like.

Although not shown, the water cooling pipe from the radiator 11 is guided to the rear wheel motor 3r through the central wiring portion 132 to cool the rear wheel motor 3r. The front wheel motor 3f is cooled by being guided directly to the front wheel motor 3f. In addition, not only the motor 3 but also the electric system such as the

inverters

8f and 8r may be cooled independently by the cooling water from the radiator 11.

The H-shaped wiring portion 13 may be attached to the vehicle body base so as to function as a part of the vehicle body structure. As a result, the rigidity of the vehicle can be increased.

(Control system)
FIG. 3 is a block diagram functionally showing the controller 10. The controller 10 is configured by a computer, for example, and includes a CPU 100, a storage unit 110 such as a semiconductor memory and a hard disk, a front wheel drive circuit 9f for driving the front wheel inverter 8f, and a rear wheel drive for driving the rear wheel inverter 8r. Circuit 9r.

The controller 10 includes the cameras 20fr and 20fl, the

encoders

16f and 16r, an accelerator sensor 22 that detects the amount of depression of the accelerator pedal, a brake sensor 23 that detects the amount of depression of the brake pedal, a shift sensor 24, An acceleration sensor (acceleration detection unit) 26, the wheel speed sensors 28fr, 28fl, 28rr, 28rl, and a steering angle sensor 29 are connected.

Encoders

16f and 16r detect the rotational speeds of the

motors

3f and 3r on the front wheel side and the rear wheel side, respectively, and output signals corresponding to the detected rotational speeds to the controller 10.

The accelerator sensor 22 detects the depression amount of the accelerator pedal and outputs a signal corresponding to the detected depression amount to the controller 10.

The brake sensor 23 detects the amount of depression of the brake pedal, and outputs a signal corresponding to the detected amount of depression to the controller 10.

The shift sensor 24 detects the position of the shift lever and outputs a signal corresponding to the detected position to the controller 10.

The acceleration sensor 26 is provided at the center of the vehicle body 25 (which is also the center of gravity G of the electric vehicle 1) 25a, and the acceleration a in the three directions of the vehicle body 25 in the forward / backward direction, the lateral direction, and the rotational direction (turning direction) around the center of gravity axis. _Y, a _X, a triaxial acceleration sensor for detecting A.theta., and outputs the detected acceleration a _Y, a _X, a signal corresponding to A.theta. the controller 10.

Wheel speed sensors 28fr, 28fl, 28rr, and 28rl detect the rotational speed ω of the wheel and output a signal corresponding to the detected rotational speed ω to the controller 10.

The steering angle sensor 29 detects an operation angle γ of the steering wheel and outputs a signal corresponding to the detected steering angle γ to the controller 10.

The controller 10 issues an operation command for performing operations such as acceleration and deceleration in accordance with operation input information generated by a driver operating an operation means such as an accelerator pedal and a brake pedal. Output to the driving circuit 9r and the mechanical brake 18 to control the driving torque (driving force) and braking torque (braking force) of the front wheel driving system and the rear wheel driving system. Thereby, the electric vehicle 1 can drive | work according to a driver | operator's operation.

The controller 10 calculates the target torque of the front wheel motor 3f and the target torque of the rear wheel motor 3Rr according to the signals from the

sensors

22, 23, 24, etc., respectively, and the front wheel drive circuit 9f and the rear wheel drive circuit are calculated. Output to 9r. On each of the front wheel side and the rear wheel side, the drive circuit 9 outputs a signal corresponding to the target torque commanded from the controller 10 to the inverter 8.

In the storage unit 110, various data such as a road surface pattern 111, a μ-SrLimit table 112, relational information on braking / driving force and slip ratio as shown in FIG. 4 described later, and various programs such as a braking / driving program 113 are stored. Stored.

The CPU 100 operates in accordance with the braking / driving program 113, so that the road surface friction coefficient μ estimating means (estimating part) 101, slip ratio upper limit setting means (setting part) 102, slip ratio calculating means (calculating part) 103, braking force control. It functions as the means (control unit) 104 and the like.

(Road surface friction coefficient μ estimation means)
The road surface friction coefficient μ estimation means 101 is based on an image captured by the front cameras 20fr and fl (the rear camera 21 when the vehicle is reverse), and the road surface on which the automobile 1 travels is a dry road surface, a wet road surface, a frozen / snow surface. It is determined whether the road surface or the like, and the friction coefficient μ of the road surface is estimated. These road surfaces are typical road surfaces with greatly different friction coefficients μ. The determination is performed by pattern matching between the captured image and the road surface pattern 111 captured in advance in each road surface condition. The road surface pattern 111 is stored in the storage unit 110 in association with the friction coefficient μ of the road surface. In addition, you may perform using the well-known technique suitably, such as performing the said determination by determination whether the brightness | luminance etc. exceeded the predetermined threshold value.

(Slip rate upper limit setting means)
FIG. 4 is a diagram showing the relationship between the driving force and braking force and the slip ratio. A solid line L1 indicates a dry road surface, a solid line L2 indicates a wet road surface, and a solid line L3 indicates a frozen / snow road surface. Each of these road surfaces is a typical road surface having a significantly different friction coefficient. The coefficient of friction is, for example, 0.75 on a dry road surface, 0.4 on a wet road surface, and 0.2 on a frozen / snow road surface. As shown in FIG. 4, the storage unit 110 stores a μ-SrLimit table 112 indicating the relationship between the road friction coefficient μ and the slip ratio upper limit value SrLimit. In the μ-SrLimit table 112, for example, the slip ratio upper limit value SrLimit1 (| Sr | = 0.16) is stored corresponding to the dry road surface (μ = 0.75), and the wet road surface (μ = 0.4). ) Is stored in response to the slip ratio upper limit value SrLimit2 (| Sr | = 0.14), and the slip ratio upper limit value SrLimit3 (| Sr | = 0) corresponding to the frozen / snow road surface (μ = 0.2). .12) is stored.

The slip ratio upper limit setting means 102 refers to the μ-SrLimit table 112 in the storage unit 110 based on the road surface friction coefficient μ estimated by the road surface friction coefficient μ estimation means 101, and determines the slip ratio upper limit as a predetermined value. Set the value SrLimit. For example, the slip ratio upper limit value SrLimit is set to a value near the maximum value of the braking / driving force that can be exhibited according to each road surface condition in FIG. 4, but is not limited to a value near the maximum value. The slip ratio upper limit value SrLimit can be set to a slip ratio at which a braking / driving force higher than 70 to 90% of the maximum braking force that can be exhibited according to the friction coefficient of the road surface, for example.

(Slip rate calculation means)
The slip ratio calculating means 103 calculates the slip ratio Sr of the wheel 2 during driving by the following formula, where V is the vehicle body speed, ω is the rotational speed of the wheel 2, and R is the radius of the wheel 2.
Sr = (Rω−V) / Rω (1)

Moreover, the slip ratio calculating means 103 calculates the slip ratio Sr of the wheel 2 at the time of braking by the following formula.
Sr = (Rω−V) / V (2)

As understood from the equation (1), when the slip ratio Sr becomes 1.0 at the time of driving, V = 0 and the wheel spin is generated. As understood from the equation (2), when the slip ratio Sr becomes −1.0 during braking, ω = 0 and a wheel lock is generated. That is, the state where the absolute value of the slip ratio Sr is 1 is a state where any braking / driving force (driving force or braking force) cannot be transmitted to the road surface. The state where the slip ratio Sr is 0 is a state where there is no slip between the wheel 2 and the road surface.

(Braking / driving force control means)
The braking / driving force control means 104 uses the μ-SrLimit table 112, the slip ratio control for controlling the slip ratio to a certain target value based on the relation information between the braking / driving force and the slip ratio as shown in FIG. Carry out wheel lock and wheel spin suppression control. Hereinafter, those controls will be described.

<Slip rate control>
The braking / driving force control means 104 compares the slip ratio | Sr | between the left and right wheels, and the driving force of the

motors

3f and 3r so that the larger slip ratio | Sr | becomes the set slip ratio upper limit value SrLimit. Alternatively, the braking force of the electric brakes of the

motors

3f and 3r and the mechanical brake 18 is controlled. The braking / driving force control means 104 controls the braking / driving force within a range not exceeding the braking / driving force depending on the depression amount of the accelerator pedal or the brake pedal.

<Control of wheel lock and wheel spin suppression with load transfer>
FIG. 5 is a diagram for explaining a method of distributing the braking force to the front wheels 2fr, 2fl and the rear wheels 2rr, 2rl in the electric vehicle 1. FIG.

As shown in FIG. 5, the braking force Fcar when the electric vehicle 1 is decelerated at the acceleration a _Y is
Fcar = M × a _Y Expression (3)
It becomes. Here, M is the mass (body mass) of the entire electric vehicle 1.

The load movement amount Z at that time is obtained by the following equation (4) in which the moment around the center of gravity G of the electric vehicle 1 generated by the braking force Fcar is converted to the vertical load at the contact point of the front wheels 2fr and 2fl and the rear wheels 2rr and 2rl. It is done.
Z = Fcar × Hcar / Lcar (4)
Here, Hcar is the height of the center of gravity G of the electric vehicle 1 from the ground contact surface, and Lcar is the wheel base of the electric vehicle 1.

When the front wheel load when the electric vehicle 1 is stopped is Wf, the rear wheel load is Wr, and the friction coefficient of the road surface is μ, the braking force of the front and rear wheels that balances the friction force, that is, the front wheels 2fr, 2fl. The maximum braking force Ffmax and the maximum braking force Frmax of the rear wheels 2rr and 2rl are expressed by the following equations (5) and (6), respectively.
Ffmax = μ (Wf + Z) (5)
Frmax = μ (Wr−Z) (6)

Therefore, if the operation of the motor 3 and the mechanical brake 18 is controlled so that the braking force by the motor 3 and the mechanical brake 18 on the front wheel side and the rear wheel side becomes the maximum braking force Ffmax and the maximum braking force Frmax, respectively. The entire vehicle 1 has the largest braking force, and wheel lock can be suppressed. The above is the explanation at the time of deceleration, but the same is true at the time of acceleration, and wheel spin can be suppressed by controlling so as to obtain an optimum driving force based on the load movement.

For example, when the electric vehicle 1 decelerates when moving forward, the load on the front wheel side increases and the load on the rear wheel side decreases due to load movement corresponding to the magnitude of acceleration. The braking force control means 104 sets the front wheel slip ratio upper limit value SrLimit to a slip ratio at which a braking force higher than 70 to 90% of the maximum braking force that can be exhibited in response to an increase in wheel load, for example, is exhibited. Can do. Further, by correcting the rear wheel side slip ratio upper limit value SrLimit so as to limit the braking force according to the decrease in the load on the rear wheel side, a braking force larger than that on the rear wheel side is generated on the front wheel side, A more appropriate braking force can be applied to each wheel 2.

In addition, when the electric vehicle 1 is accelerated when moving forward, the load on the front wheel side is reduced and the load on the rear wheel side is increased by moving the load according to the magnitude of the acceleration. The braking force control means 104 sets the rear wheel slip ratio upper limit value SrLimit to a slip ratio at which a driving force higher than 70 to 90% of the maximum braking force that can be exhibited in response to an increase in wheel load, for example. be able to. In addition, by correcting the front wheel side slip ratio upper limit value SrLimit so as to limit the driving force according to the decrease in the load on the front wheel side, a larger driving force is generated on the rear wheel side than on the front wheel side, and more appropriately Drive force can be applied to each wheel 2.

(Effect of embodiment)
According to the present embodiment, the following effects can be obtained.
(1) By arranging the

motors

3f and 3r and the

inverters

8f and 8r in a point-symmetric manner and arranging the pair of high-voltage batteries 60r and 60l in a line-symmetric manner, the center of gravity G is located substantially at the center 25a of the vehicle body 25 and travels. It is excellent in stability.
(2) By disposing the front wheel motor 3f on the side opposite to the driver's seat 9 with respect to the center line Lc, and separating the front wheel motor 3f from the driver's seat, the driver's safety when the front wheel motor 3f is damaged is improved. Therefore, vibrations and motor sounds generated from the front wheel motor 3f are hardly transmitted to the driver. For this reason, comfortable operation performance can be ensured.
(3) Since the radiator 11, the controller 10, the low voltage battery 7, the pressure adjustment unit 12, and the like are arranged in front of the left and right wheels 2fr and 2fl on the front wheel side, the front bonnet is opened and the control system is inspected. Becomes easier.
(4) Since the pair of high voltage batteries 60r and 60l are connected in parallel to each other, even if one of the pair of high voltage batteries 60r and 60l breaks down, DC power is supplied from the other high voltage battery 60. be able to.
(5) When replacing the high-voltage batteries 60r and 60l, it can be easily performed by attaching and detaching the bus bar 62 from the side of the vehicle body 25.
(6) Since the signal cable 141 and the power cable 142 can be separated by the

partition walls

13e and 13f of the H-shaped wiring part 13, electromagnetic wave noise generated from the power cable 142 is mixed in the signal transmitted through the signal cable 141. Can be suppressed.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, each of the units 101 to 104 is realized by the CPU 100 and the braking / driving program 113, but may be realized by hardware such as ASIC (Application Specific IC).

Further, the braking / driving program 113 may be taken into the controller 10 from a recording medium such as a CD-ROM, or may be taken into the controller 10 from a server device or the like via a network.

In the above embodiment, the radiator is disposed in front of the vehicle body, but may be disposed in front of and behind the vehicle body.

The present invention can be applied to vehicles such as passenger cars, buses and trucks.

DESCRIPTION OF SYMBOLS 1 ... Electric vehicle, 2 ... Wheel, 2fr, 2fl ... Front wheel, 2rr, rl ... Rear wheel, 3f ... Front wheel motor, 3r ... Rear wheel motor, 4f, 4r ... Differential device, 5fr, 5fl, 5rr, 5rl Axle, 6 ... main power supply, 7 ... low voltage battery, 8f ... front wheel inverter, 8r ... rear wheel inverter, 9f ... front wheel drive circuit, 9r ... rear wheel drive circuit, 10 ... controller, 11 ... radiator , 12 ... Pressure adjustment unit, 13 ... H-shaped wiring part, 13a ... Upper wall, 13b ... Lower wall, 13c, 13d ... Side wall, 13e, 13f ... Partition wall, 15a-15c ... Current sensor, 16f, 16r ... Encoder, 17a to 17c: current sensor, 18fr, 18fl, 18rr, 18rl ... mechanical brake, 20fr, 20fl ... camera, 21 ... camera, 22 ... accelerator sensor, 23 ... brake Sensor, 24 ... shift sensor, 25 ... vehicle body, 25a ... center of vehicle body, 26 ... acceleration sensor, 27f, 27r ... temperature sensor, 28fr, 28fl, 28rr, 28rl ... wheel speed sensor, 29 ... steering angle sensor, 60r, 60l ... high voltage battery, 61r, 61l ... smoothing capacitor, 62 ... bus bar, 100 ... CPU, 101 ... road surface friction coefficient μ estimation means, 102 ... slip ratio upper limit setting means, 103 ... slip ratio calculation means, 104 ... braking force control Means: 110: storage unit, 111: road surface pattern, 112: μ-SrLimit table, 113: braking / driving program, 130: front wiring unit, 131: rear wiring unit, 132: central wiring unit, 141: signal cable, 130a, 131a, 132a _1, 132a ₂ ... signal cabling areas, 130b, 131b, 132b ... Sources cabling area, 142 ... power cable

Claims

A first electric motor that transmits braking / driving force to the left and right wheels on the front wheel side;
A second electric motor that transmits braking / driving force to the left and right wheels on the rear wheel side;
A first inverter for driving the first electric motor;
A second inverter for driving the second electric motor,
The first and second electric motors are arranged in line symmetry or point symmetry with respect to the center of the vehicle body,
The first and second inverters are arranged in line symmetry when the first and second electric motors are arranged in line symmetry, and the first and second electric motors are arranged in point symmetry. When you have an electric car arranged symmetrically.
A first electric motor that transmits braking / driving force to the left and right wheels on the front wheel side via the first differential;
A second electric motor for transmitting braking / driving force to the left and right wheels on the rear wheel side via a second differential;
A first inverter for driving the first electric motor;
A second inverter for driving the second electric motor;
A radiator for cooling the first and / or second electric motor;
A controller that controls the first and second inverters to control the braking / driving force output by the first and second electric motors;
A front wheel and a rear wheel drive system including a pair of batteries connected in parallel to each other and supplying DC power to the first and second inverters;
The first and second electric motors are arranged in line symmetry or point symmetry with respect to the center of the vehicle body, and the first and second inverters are arranged in line symmetry with the first and second electric motors. When the first and second electric motors are arranged point-symmetrically, they are arranged point-symmetrically, the first and second electric motors, and the first And the radiator, the controller, and the pair of batteries so as to cancel a moment around an axis passing through the center of the vehicle body when the second inverter is arranged in line contrast or point contrast with respect to the center of the vehicle body An electric vehicle in which the front wheel and rear wheel drive systems are arranged.
The first electric motor is disposed in front of the center of the vehicle body and on the opposite side of the driver seat disposed to be shifted from the center line along the front-rear direction of the vehicle body,
The second electric motor is disposed in a point contrast position with respect to the first electric motor;
The first inverter is disposed in front of the center of the vehicle body and on the driver's seat side,
The second inverter is an electric vehicle arranged at a point contrast with respect to the first inverter.
A low-voltage battery that outputs a voltage lower than the voltage output by the pair of batteries;
The electric vehicle according to claim 2 or 3, wherein the first electric motor, the first inverter, the radiator, the low-voltage battery, and the controller are arranged in front of the left and right wheels on the front wheel side.
5. The first and second electric motors, the first and second inverters, the pair of batteries, the low-voltage battery, and the controller are wired via an H-shaped wiring unit. Electric car.
The H-shaped wiring portion includes a front wiring portion parallel to the front wheel axle, a rear wiring portion parallel to the rear wheel axle, a center connecting the center of the front wiring portion and the center of the rear wiring portion. With wiring part,
The electric vehicle according to claim 5, wherein the pair of batteries are configured to be detachable from the central wiring portion from a side surface direction of a vehicle body.
The electric vehicle according to claim 6, wherein the water pipe from the radiator is led to a second electric motor through the central wiring portion of the H-shaped wiring portion.
The electric vehicle according to claim 5, 6 or 7, wherein the H-shaped wiring part has a power cable and a signal cable separated by a partition wall.