JP2018135032A - Brake control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking device for a vehicle that is able to hinder a rotating speed of a drive source for traveling from exceeding the upper limit rotating speed during braking of the vehicle and prevent abnormal states and so on of the drive source for traveling.SOLUTION: A brake device 68 for a vehicle brakes each of wheels of the vehicle comprises: two electric motors: and left and right wheel drive device provided between the two electric motors and the left and right wheels and configured to amplify a difference between torques applied from the two electric motors and transmit the amplified difference to the left and right wheels. The brake device 68 comprises a brake control device 69 that controls a brake force drive source 70a on the basis of a given brake output command value. The brake control device 69 comprises: a regular control section 73 that controls a brake force drive source 70a so as to have the given brake output command value; and a command value correcting section 74 that, if the rotating speed of either one of the electric motors increases and exceeds a threshold during braking, corrects the brake output command value corresponding to each of the left and right wheels, according to a predetermined condition.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a braking device for a vehicle including left and right wheel drive devices that amplify drive torque generated from two independent driving sources for driving and transmit the amplified torque to left and right drive wheels.

  In order to achieve smooth turning of the vehicle or to suppress changes in vehicle behavior such as extreme understeer and extreme oversteer, a large drive torque difference may be generated between the left and right drive wheels. May be valid. Therefore, a left and right wheel drive device is disclosed that includes a gear device in which two planetary gear mechanisms are combined between two drive sources and left and right drive wheels, and amplifies the difference in torque (Patent Documents 1 and 2). ). The planetary gear mechanism of the gear device amplifies the torque difference between the two drive sources and transmits it to the left and right drive wheels. In addition, application of an electric motor as a drive source is shown.

JP-A-2015-21594 Japanese Patent No. 4907390

In the left and right wheel drive device described above, the difference in torque between the two drive sources is amplified. On the other hand, the difference in rotation speed between the left and right drive wheels is enlarged to become the difference in rotation speed between the two drive sources. Torque difference amplification factor α (α> 1), reduction ratio β (β ≧ 1), torques of the two drive sources are TM1 and TM2, respectively, and left and right wheel torques are TWL and TWR, respectively. Can be expressed by the following equation.
TWL + TWR = β (TM1 + TM2) (1)
TWL-TWR = αβ (TM1-TM2) (2)

Similarly, assuming that the rotational speeds of the two driving sources are ωM1 and ωM2, and the rotational speeds of the left and right wheels are ωWL and ωWR, the relationship between the rotational speeds can be expressed by the following formula.
ωM1 + ωM2 = β (ωWL + ωWR) (3)
ωM1−ωM2 = αβ (ωWL−ωWR) (4)

  When a brake is applied while the vehicle is running, a difference occurs in the braking force that acts on the tire from the road surface if the friction coefficient is different on the left and right sides. For this reason, a difference also arises in the rotational speed of the left and right drive wheels. In the left and right wheel drive device, the difference in rotation speed between the left and right wheels is amplified by the amplification factor α and the reduction ratio β, so that the rotation speed of one drive source is greatly reduced, but the rotation speed of the other drive source is decreased. It may increase instead. Therefore, especially in high-speed driving conditions where the drive source is close to the upper limit rotational speed, the difference between the rotational speeds of the left and right drive wheels increases by braking on the road surface with different friction coefficients on the left and right. In spite of the decrease, there is a possibility that the rotation speed of the drive source exceeds the upper limit rotation speed at which the drive source can rotate.

  FIG. 11 is a diagram showing the above situation. Indicates the time change of the rotation speed of the left and right drive wheels, the rotation speed of the left and right motors that are the two drive sources, and the brake output command value of the left and right drive wheels when the vehicle is braked while traveling at high speed. ing. The road friction coefficient in this example is low μ for the right driving wheel and high μ for the left driving wheel. In order to simplify the explanation, the reduction ratio β is “1”.

  In FIG. 11, the vehicle is traveling at a speed such that the rotational speed of the motor is close to the motor upper limit rotational speed until time t11. At time t11, the vehicle starts braking, and the brake output command value increases greatly. At this time, the rotational speed of the driving wheel decreases, but the right driving wheel has a low μ road and tends to be locked, and the rotational speed is greatly decreased. The rotational speed difference Δω generated between the left and right drive wheels is amplified by the amplification factor α to become two motor rotational speed differences αΔω, and the rotational speed of the right motor is greatly reduced, but the rotational speed of the left motor is greatly increased. The motor upper limit rotational speed is exceeded at time t12 (see the one-dot chain line in FIG. 11).

In the example of FIG. 11, since the vehicle has an antilock brake control function, the right drive wheel falls below the ABS target rotation speed indicated by the two-dot chain line in FIG. It functions and adjusts the brake output command value of the right drive wheel so that the rotation speed of the right drive wheel becomes the ABS target rotation speed.
When the motor rotation speed exceeds the upper limit rotation speed as shown in FIG. 11, the motor rotor may be deformed or abnormal due to centrifugal force, which may cause output reduction, rotation inability, or vibration increase.

  An object of the present invention is to provide a vehicle braking device capable of preventing the traveling drive source from exceeding an upper limit rotational speed during braking of the vehicle and preventing an abnormality of the traveling drive source. is there.

The vehicle braking device according to the present invention is provided between two drive sources for driving 2L, 2R that can be controlled independently, and between these two drive sources for driving 2L, 2R and the left and right wheels 61L, 61R. A braking device 68 that brakes each wheel of the vehicle provided with the left and right wheel drive device 1 that amplifies the difference in torque applied from the two traveling drive sources 2L and 2R and transmits it to the left and right wheels 61L and 61R, respectively. Because
Braking force generating means 70 including a braking force drive source 70a for generating a braking force on each wheel;
Brake control devices 69 and 69A for controlling the braking force drive source 70a based on a given brake output command value,
The brake control devices 69 and 69A are
A normal control unit 73 for controlling the braking force drive source 70a so as to obtain a given brake output command value;
A command for correcting brake output command values corresponding to the left and right wheels 61L and 61R according to a predetermined condition when the rotational speed of any one of the driving drive sources 2L (2R) increases and exceeds a threshold during braking. A value correction unit 74.
The predetermined condition is an arbitrary condition determined by design or the like, and is determined, for example, by obtaining an appropriate condition by one or both of testing and simulation.

According to this configuration, the brake control devices 69 and 69A control the braking force drive source 70a based on the applied brake output command value. As a result, the braking force drive source 70a generates a braking force on each wheel. Of the brake control devices 69 and 69A, the normal control unit 73 controls the braking force drive source 70a so as to obtain a given brake output command value. Of the brake control devices 69 and 69A, the command value correction unit 74 determines whether the rotational speed of any one of the driving sources for driving 2L (2R) increases and exceeds a threshold during braking. The command value correction unit 74 corrects the brake output command values corresponding to the left and right wheels according to a predetermined condition when it is determined that the rotational speed increases and exceeds the threshold value.
The torque relational expression between the driving sources 2L and 2R for traveling and the left and right wheels 61L and 61R and the relational expressions for the rotational speeds of the driving sources 2L and 2R for traveling and the left and right wheels 61L and 61R are both the amplification factor α and the like. Therefore, when the rotational speed of any one of the driving sources 2L (2R) increases and exceeds the threshold value when the vehicle speed decreases, the brake output command value is corrected to correct the left and right The difference in rotational speed between the wheels 61L and 61R can be reduced, and the rotational speed of the travel drive source 2L (2R) can be made lower than the upper limit rotational speed. Accordingly, it is possible to prevent the traveling drive source 2L (2R) from being over-rotated and prevent the traveling drive source 2L (2R) from being abnormal.
In this way, right and left wheels that amplify the difference in torque between the two travel drive sources 2L and 2R by an amplification factor α, instead of performing control to directly limit the rotational speed of the travel drive source 2L (2R). Depending on the characteristics of the drive device 1, when the rotational speed of the travel drive source 2 </ b> L (2 </ b> R) increases during braking and exceeds the threshold value, control for correcting the brake output command value is performed. It is possible to reduce the rotational speed difference between the left and right wheels 61L and 61R more easily and reliably than directly limiting the rotational speed of 2R), and the rotational speed of the driving source 2L (2R) for traveling is set to the upper limit rotational speed. It can be: Accordingly, it is possible to prevent the traveling drive source 2L (2R) from being over-rotated and prevent the traveling drive source 2L (2R) from being abnormal.

The command value correction unit 74 may correct the brake output command value as the predetermined condition so that the increased rotational speed of the traveling drive source 2L (2R) is equal to or less than the threshold value. In this case, since the brake output command value is corrected so that the rotational speed is equal to or less than the threshold value, the rotational speed difference between the left and right wheels 61L and 61R can be more reliably reduced.
The threshold value is a threshold value arbitrarily determined by design or the like, and is determined by obtaining an appropriate threshold value by one or both of testing and simulation, for example.
The threshold value may be determined based on an upper limit rotation speed of the traveling drive source 2L (2R). The command value correction unit 74 may set a value lower than the motor upper limit rotation speed as a threshold value, and correct the brake output command value when the threshold value is exceeded. Thus, by using a value lower than the motor upper limit rotational speed as a threshold value, an increase in the motor rotational speed due to a response delay of the friction brake 70 during braking can be suppressed.

The command value correction unit 74 corrects the brake output command values corresponding to the left and right wheels 61L and 61R so that the rotational speed difference between the left and right wheels 61L and 61R is reduced as the predetermined condition. Also good.
In the conventional example, in a high-speed driving state where the driving source for driving is close to the upper limit rotation speed, the driving for driving is performed by applying a brake on the road surface having different road surface friction coefficients on the left and right, thereby increasing the difference in rotational speed between the left and right wheels. There is a possibility that the rotation speed of the source exceeds the upper limit rotation speed.
According to this configuration, the driving for traveling is corrected regardless of the vehicle traveling state by correcting the brake output command value corresponding to the left and right wheels 61L, 61R so that the difference in rotational speed between the left and right wheels 61L, 61R becomes small. It is possible to prevent the rotational speeds of the sources 2L and 2R from exceeding the upper limit rotational speed.

  The command value correction unit 74 increases a brake output command value corresponding to a wheel having a high rotational speed among the left and right wheels 61L and 61R, or decreases a brake output command value corresponding to a wheel having a low rotational speed. You may correct to.

The brake control device 69 includes an ABS control unit 72 that performs anti-lock brake control based on a given brake output command value and the rotational speed of the wheel, and the command value correction unit 74 receives the command from the ABS control unit 72. You may correct | amend the output brake output command value according to the defined conditions.
The predetermined condition is an arbitrary condition determined by design or the like, and is determined, for example, by obtaining an appropriate condition by one or both of testing and simulation.

The left and right wheel drive device 1 may have two planetary gear mechanisms 30L and 30R.
The driving source for traveling may be electric motors 2L and 2R.

  The braking device for a vehicle according to the present invention is provided between two independently drivelable drive sources that are controllable, and between these two travel drive sources and the left and right wheels, and is provided from the two travel drive sources. A braking device that brakes each wheel of a vehicle including a left and right wheel drive device that amplifies a difference in torque generated and transmits the difference to the left and right wheels, respectively, and generates a braking force on each wheel And a brake control device that controls the braking force drive source based on a given brake output command value, so that the brake control device has a given brake output command value. A normal control unit for controlling the braking force drive source, and a brake output command value corresponding to the left and right wheels when the rotational speed of any one of the driving sources for driving increases and exceeds a threshold during braking. And a command value correcting portion for correcting in accordance with conditions. For this reason, at the time of braking of a vehicle, it can suppress that the rotational speed of the drive source for driving exceeds an upper limit rotational speed, and can prevent abnormality etc. of the drive source for driving.

It is a block diagram which shows the conceptual structure of the vehicle by which the braking device which concerns on embodiment of this invention is mounted. It is sectional drawing of the left-right wheel drive device of the vehicle. It is sectional drawing which expands and shows the gear apparatus part of the left-right wheel drive device. It is a skeleton figure which shows the same right-and-left wheel drive device. It is explanatory drawing of the electric vehicle carrying the left-right wheel drive device. It is a speed diagram for demonstrating the torque difference gain by the same right-and-left wheel drive device. It is a block diagram of a brake control device or the like of the braking device. It is the flowchart which showed the braking operation | movement in the wheel with the brake control apparatus. It is a block diagram of the brake control device concerning other embodiments of this invention. It is a figure which shows the time change of the rotational speed of the left-and-right wheel at the time of the braking by the braking device which concerns on either embodiment, the rotational speed of the left-and-right electric motor, and the brake output command value of the left-and-right wheel. It is a figure which shows the time change of the rotational speed of the left-right wheel at the time of the braking of the vehicle by a prior art example, the rotational speed of the left-right electric motor, and the brake output command value of a left-right wheel.

A vehicle braking apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing a conceptual configuration of a vehicle (electric vehicle) on which this braking device is mounted. This vehicle has a rear wheel drive system, and includes a chassis 60, drive wheels 61L and 61R as rear wheels, driven wheels 62L and 62R as front wheels, left and right wheel drive device 1, vehicle control device 66, motor control. A device 67, a battery 63, an inverter device 64, a braking device 68, and the like are provided.

  The left and right wheel drive device 1 includes first and second electric motors 2L and 2R, and left and right speed reducers 3L and 3R each having a gear device 30. The first and second electric motors 2L and 2R are two driving sources that are mounted on the vehicle and can be controlled independently. The gear device 30 is provided between the first and second electric motors 2L and 2R and the drive wheels 61L and 61R.

<Basic configuration of control system>
The vehicle control device 66 is a higher-level control unit of the motor control device 67 and the brake control device 69, and has a function of performing overall control and cooperative control of the entire vehicle, for example. Further, the vehicle control device 66 determines the braking / driving force necessary for the vehicle based on information such as the driver's accelerator pedal operation or brake pedal operation, and determines the motor torque command value of the left and right wheel drive device 1 or the friction brake 70. The brake output command value is output to the motor control device 67 or the brake control device 69, respectively.

  The motor control device 67 outputs the motor torque command values that should be generated by the first and second electric motors 2L and 2R to the inverter device 64 based on the motor torque command values given from the vehicle control device 66. Further, the motor control device 67 has a fail-safe function for correcting the motor torque command value according to the motor rotation speed or the motor coil temperature.

  The inverter device 64 converts the DC power of the battery 63 into AC power for driving the first and second electric motors 2L, 2R. The inverter device 64 controls the current supplied from the battery 63 so that the torque output from the first and second electric motors 2L and 2R is equal to the motor torque command value, and controls the first and second electric motors 2L and 2R. Drive. The output from the left and right wheel drive device 1 is transmitted to the left and right drive wheels 61L and 61R via constant velocity joints 65a and 65a (FIG. 2). The torques output from the first and second electric motors 2L and 2R are amplified by the torque difference amplification factor α and the reduction ratio β in the gear device 30 and output to the left and right drive wheels 61L and 61R.

  In order to realize the received brake output command value, the brake control device 69 controls a driving force such as a hydraulic pressure or an electric motor, and operates a friction brake 70 that is a braking force generating means provided in each wheel. When the brake control device 69 has an anti-lock brake control function to be described later, the slip ratio for each wheel is calculated based on the output of the rotational speed sensor 71 (FIG. 7) of each wheel, When the rotational speed is lower than the target rotational speed, the braking force by the friction brake 70 is adjusted so that the target rotational speed is reached.

<Left and right wheel drive device 1>
<< About the first and second electric motors 2L and 2R >>
In this embodiment, the first and second electric motors 2L and 2R in the left and right wheel drive device 1 use the same standard electric motors having the same maximum output.
As shown in FIG. 2, the first and second electric motors 2L and 2R include motor housings 4L and 4R, stators 6 and 6, and rotors 5 and 5, respectively. The first and second electric motors 2L and 2R are radial gap types in which the stators 6 and 6 are provided on the inner peripheral surfaces of the motor housings 4L and 4R, and the rotor 5 is provided on the inner periphery of each stator 6 at intervals. is there.

  The motor housings 4L and 4R include cylindrical motor housing bodies 4aL and 4aR, outer walls 4bL and 4bR, and inner walls 4cL and 4cR. The outer side walls 4bL and 4bR close the outer surface on the outboard side of the motor housing main bodies 4aL and 4aR. The inner side walls 4cL, 4cR are provided on the inner side surface of the motor housing main bodies 4aL, 4aR on the inboard side, and form partition walls that are separated from the reduction gears 3L, 3R. The inner walls 4cL and 4cR are provided with openings for pulling out the motor shafts 5a to the inboard side. In this specification, the side closer to the outside in the vehicle width direction of the vehicle when the left and right wheel drive device 1 is mounted on the vehicle is referred to as the outboard side, and the side closer to the center in the vehicle width direction of the vehicle is referred to as the inboard side. Called the board side.

  The stators 6 and 6 are fitted and fixed to the inner peripheral surfaces of the motor housing main bodies 4aL and 4aR. The rotor 5 has a motor shaft 5a at the center. Rolling bearings 8a and 8b are provided on the inner walls 4cL and 4cR and the outer walls 4bL and 4bR. Each motor shaft 5a is rotatably supported by motor housings 4L and 4R via rolling bearings 8a and 8b. The left and right motor shafts 5a, 5a are provided on the same axis (coaxial).

<< About the reduction gear 3 >>
The speed reduction device 3 includes left and right speed reduction devices 3L and 3R. The speed reduction devices 3L and 3R include a housing 9, input gear shafts 12L and 12R, intermediate gear shafts 13L and 13R, output gear shafts 14L and 14R, and gears. Device 30 (FIG. 3). The reduction gears 3L and 3R amplify the difference in torque (driving torque) input from the motor shaft 5a of the first and second electric motors 2L and 2R with the gear device 30 (FIG. 3), and transfer them to the driving wheels 61L and 61R. It is a device that communicates.

  The housing 9 accommodates these gear shafts and the gear device 30 (FIG. 3). The housing 9 has a structure divided into three pieces. Specifically, the housing 9 includes a central housing 9a and left and right side housings 9bL and 9bR fixed to both side surfaces of the central housing 9a. The side surface on the outboard side of the side housings 9bL and 9bR and the inner side walls 4cL and 4cR are fixed with a plurality of bolts. Thereby, the two electric motors 2L and 2R are fixed to the left and right ends of the housing 9.

  A partition wall 11 is provided in the center of the center housing 9a. The housing 9 is divided into left and right parts by the partition wall 11 and accommodates the main body portions of the left and right reduction gears 3L and 3R. The main body portion is symmetrical, and includes input gear shafts 12L and 12R, intermediate gear shafts 13L and 13R, output gear shafts 14L and 14R, and a gear device 30 (FIG. 3).

  The input gear shafts 12L and 12R have an input gear 12a to which power is transmitted from the motor shaft 5a. Rolling bearings 17a and 17b are provided in the bearing fitting holes formed in the partition wall 11 and the bearing fitting holes formed in the left and right side housings 9bL and 9bR. Both ends of the input gear shafts 12L and 12R are rotatably supported by the housing 9 via rolling bearings 17a and 17b. The input gear shafts 12L and 12R have a hollow structure. The end portions on the inboard side of the motor shafts 5a are inserted into the hollow interiors of the input gear shafts 12L and 12R. The input gear shafts 12L, 12R and the motor shafts 5a are coupled by splines (including “serration”. The following splines also include “serration”).

  As shown in FIG. 3, the left and right intermediate gear shafts 13L and 13R are arranged coaxially. The intermediate gear shafts 13L and 13R have large-diameter input-side external gears 13a and 13a that mesh with the input gears 12a and 12a, and output-side small-diameter gears 13b and 13b that mesh with output gears 14a and 14a described later. Rolling bearings 20a and 20b are provided in bearing fitting holes 19a formed in the partition wall 11 and bearing fitting holes 19b formed in the left and right side housings 9bL and 9bR. Both ends of the intermediate gear shafts 13L and 13R are rotatably supported by the housing 9 via rolling bearings 20a and 20b. The bearing fitting holes 19a and 19b have a stepped shape with which the outer ring end faces of the rolling bearings 20a and 20b come into contact, and pass through so that first and second coupling members 31 and 32, which will be described later, pass through.

  A gear device 30 is incorporated in the intermediate gear shafts 13L and 13R coaxially with the intermediate gear shafts 13L and 13R. The gear device 30 amplifies the difference in torque (drive torque) applied from the two electric motors 2L and 2R (FIG. 2). The gear device 30 includes two planetary gear mechanisms 30L and 30R having three elements and two degrees of freedom. In this example, a single pinion planetary gear mechanism is employed for the planetary gear mechanisms 30L and 30R. The two planetary gear mechanisms 30L and 30R are provided coaxially.

Planetary gear mechanism 30L, 30R is the ring gear _R L, and _{R R,} the sun gear _S L, _S and _R, the planetary gear _P L, and _{P R,} the planet carrier _C L, and _{C R,} the first, second coupling member 31 , 32. Ring gear _R L, _{R R,} an intermediate gear shaft 13L, 13R of the input-side external gear 13a, a gear inner incorporated respectively 13a. The sun gears S _L and S _R are sun gears provided coaxially with the ring gears R _L and R _R. Planetary gears _P L, _{P R} is the revolution gear meshing with the ring gear _R L, _{R R} and the sun gear _S L, _{S R.} Planet carrier _C L, _{C R} is the planetary gear _P L, is connected to the _{P R,} is provided a ring gear _R L, the _{R R} coaxially. Planet carrier _C L, the _{C R,} the intermediate gear shaft 13L, the output-side small-diameter gear 13b of the 13R, 13b are connected.

The first coupling member 31, coupling one and planet carrier C _L which is a constituent member of Figure 3 the left planetary gear mechanism 30L, the other of the sun gear S _R which is a component of the right side in FIG. 3 of the planetary gear mechanism 30R To do. The second coupling member 32 is coupled while the sun gear S _L of a component of Figure 3 the left planetary gear mechanism 30L, and the other of the planet carrier C _R is a structural member of FIG. 3 the right planetary gear mechanism 30R To do.

Planet carrier _C L, _{C R} has planetary gears _P L, a carrier pin 33 which supports the _{P R,} and the carrier flange 34a on the outboard side, and a carrier flange 34b on the inboard side. Planetary gears _P L, _{P R} is supported on a carrier pin 33 through needle roller bearings 37. The outboard carrier flange 34 a is connected to the outboard side end of the carrier pin 33. The inboard carrier flange 34 b is connected to the inboard side end of the carrier pin 33.

The carrier flange 34a on the outboard side includes a hollow shaft portion 35 extending toward the outboard side. The end portion on the outboard side of the hollow shaft portion 35 is supported by a bearing fitting hole formed in the side housings 9bL and 9bR via a rolling bearing 20b. The carrier flange 34b on the inboard side includes a hollow shaft portion 36 that extends toward the inboard side. An end portion on the inboard side of the hollow shaft portion 36 is supported in a bearing fitting hole formed in the partition wall 11 via a rolling bearing 20a. Each carrier flanges 34a, 34b outer peripheral surface and the ring gear _R L of the, between the _{R R,} the rolling bearing 39a, 39b is provided.

  The first and second coupling members 31 and 32 that connect the two planetary gear mechanisms 30L and 30R to each other are incorporated through the partition wall 11 that partitions the central housing 9a left and right. The first and second coupling members 31 and 32 are positioned coaxially with each other and are supported by the thrust bearing 47 so as to be rotatable in the axial direction and supported by the deep groove ball bearing 49 so as to be rotatable in the radial direction. Further, between the first and second coupling members 31, 32, bearings 45, 46 and a thrust bearing 48 different from the bearings 47, 49 are provided. As the other bearings 45 and 46, needle roller bearings are applied, respectively. The second coupling member 32 has a hollow shaft, and the first coupling member 31 has a shaft inserted through the hollow shaft.

And the outer circumferential surface of the right side in FIG. 3 on the outboard side, spline meshing with each other in the hollow shaft portion 36 of the carrier flange 34b on the inboard side of the planet carrier C _R are provided in the second coupling member 32. Thus, the second coupling member 32 is coupled by spline fitting to the planet carrier C _R. Therefore, the planet carrier C _R is a second rotary member rotates together with the second coupling member 32.

And the outer circumferential surface of the left side of FIG. 3 on the outboard side, spline meshing with each other in the hollow shaft portion 35 of the carrier flange 34a on the outboard side of the planet carrier C _L is provided in the first coupling member 31. Thus, the first coupling member 31 is connected by spline engagement to the planet carrier C _L. Therefore, the planet carrier C _L is a first rotating member rotates together with the first coupling member 31.

As described above, first, second coupling member 31 and 32, because it is attached by spline fitting to the planet carrier _C L, _{C R,} two planetary gear mechanisms 30L, 30R is divisible into right and left Thus, the three-piece structure housing 9 can be incorporated from the left and right together with other reduction gear shafts. End of the planet carrier C _L side of the second coupling member 32 has, on its outer circumferential surface, an external gear which constitutes the sun gear S _L in FIG. 3 the left planetary gear mechanism 30L is formed. The external gear that constitutes the sun gear S _L meshes with the planetary gear P _L.

The first coupling member 31 has a large-diameter portion 43 at the end on the planetary gear mechanism 30R side on the right side of FIG. This outer peripheral surface of the large diameter portion 43, an external gear which constitutes the sun gear S _R in FIG. 3 the right planetary gear mechanism 30R is formed. External gear constituting the sun gear S _R is engaged with the planetary gears P _R. Thrust bearings 47 and 48 are provided at both axial ends of the second coupling member 32. These thrust bearings 47 and 48, first, second coupling members 31, 32 and the planetary carrier _C L, axial movement by sliding of the spline fitting portion between _{C R} is regulated.
The first coupling member 31, the end of the right side in FIG. 3 is supported by a deep groove ball bearing 49 relative to the planet carrier C _R. An oil supply hole is provided in the axial center of the first coupling member 31.

  As shown in FIG. 2, the output gear shafts 14L and 14R have a large-diameter output gear 14a. Rolling bearings 54a and 54b are provided in the bearing fitting holes formed in the partition wall 11 and the bearing fitting holes formed in the left and right side housings 9bL and 9bR. The output gear shafts 14L and 14R are rotatably supported by the housing 9 via rolling bearings 54a and 54b.

  Outboard end portions of the output gear shafts 14L and 14R are drawn out of the housing 9 from openings formed in the side housings 9bL and 9bR. The outer joint portion of the constant velocity joint 65a is splined to the outer peripheral surface of the end portion on the outboard side of the drawn output gear shafts 14L and 14R. Each constant velocity joint 65a is connected to drive wheels 61L and 61R (FIG. 1) via an intermediate shaft (not shown).

  FIG. 4 is a skeleton diagram showing the left and right wheel drive device. FIG. 5 is an explanatory diagram of an electric vehicle equipped with the left and right wheel drive device. As shown in FIGS. 4 and 5, the left and right electric motors 2L and 2R are individually controlled by the motor control device 67 (FIG. 1), and can generate and output different torques.

The torque of the electric motors 2L and 2R is increased by the gear ratio between the input gear 12a of the input gear shafts 12L and 12R of the reduction gears 3L and 3R and the large-diameter input side external gear 13a of the intermediate gear shafts 13L and 13R. And transmitted to the ring gears R _L and R _R of the gear device 30. Then, the gear device 30 amplifies the difference between the left and right torques, and transmits the torque to the output-side small-diameter gear 13b. Further, the torque is further amplified by the gear ratio between the output-side small-diameter gear 13b and the output gear 14a, and is output to the drive wheels 61L and 61R.

Planetary gear mechanism 30L in gear 30, 30R, the sun gear _S L disposed coaxially, _{S R} and the ring gear _R L, and _{R R,} these sun gear _S L, _{S R} and the ring gear _R L, between the _{R R} position the planetary gear _P L, and _{P R,} the planetary gear _P L, _{P R} and the rotatably supported sun gear _S L, _{S R} and the ring gear _R L, _{R R} and planet carrier _C L provided coaxially, and _{C R} Have Here, the sun gear _S L, _{S R} and planetary gears _P L, the _{P R} is an external gear having gear teeth on the outer periphery, a ring gear _R L, _{R R} is an internal gear having gear teeth on the inner periphery. Planetary gears _P L, _{P R} is engaged the sun gear _S L, _{S R} and the ring gear _R L, in the _{R R.}

Planetary gear mechanism 30L, the 30R, the planetary carrier _C L, the sun gear _S L in case of fixing the _{C R, S R} and the ring gear _R L, and the _{R R} is rotated in the reverse direction. Thus, expressed in the velocity diagram shown in FIG. 6, the ring gear _R L, _{R R} and the sun gear _S L, _{S R} are disposed on the opposite side of the planet carrier _C L, _{C R.}

  As shown in FIGS. 4 and 5, the torque TM1 generated by the electric motor 2L is transmitted from the input gear shaft 12L to the intermediate gear shaft 13L. The torque transmitted to the intermediate gear shaft 13L is amplified by the gear device 30 so that the left and right torque difference is amplified, and the output side small gear 13b, the output gear 14a, and the output gear of the intermediate gear shaft 13L are sequentially transmitted via the planetary gear mechanism 30L. It is transmitted to the shaft 14L. A driving torque TL (FIG. 6) is output from the output gear shaft 14L to the driving wheel 61L.

  Torque TM2 generated by the electric motor 2R is transmitted from the input gear shaft 12R to the intermediate gear shaft 13R. The torque transmitted to the intermediate gear shaft 13R is amplified by the gear device 30 so that the difference in torque between the left and right sides is sequentially increased through the planetary gear mechanism 30R, and the output side small gear 13b, the output gear 14a, and the output gear of the intermediate gear shaft 13R. It is transmitted to the shaft 14R. A driving torque TR (FIG. 6) is output from the output gear shaft 14R to the driving wheel 61R.

<About driving torque>
Here, the driving torque transmitted by the gear device 30 will be described with reference to a velocity diagram shown in FIG. Since the gear unit 30 is configured by combining two identical single pinion planetary gear mechanisms 30L and 30R, it can be represented by two velocity diagrams as shown in FIG. Here, for easy understanding, the two speed diagrams are shifted up and down, the speed diagram of one planetary gear mechanism 30L is shown on the upper side of FIG. 6, and the speed line of the other planetary gear mechanism 30R is shown on the lower side of FIG. The figure is shown.

Originally, as shown in FIG. 5, the torques TM1 and TM2 output from the electric motors 2L and 2R are connected to the ring gears via the input side external gears 13a meshing with the input gears 12a of the input gear shafts 12L and 12R. Since it is input to R _L and R _R , a reduction ratio is applied. Further, since the drive torques TL and TR output from the gear device 30 are transmitted to the left and right drive wheels 61L and 61R via the output side small gear 13b meshing with the output gear 14a, a reduction ratio is applied.
These left and right wheel drive devices are applied with these reduction ratios, but for the sake of easy understanding, hereinafter, as shown in FIG. The torque input to R _L and R _R remains TM1 and TM2, and the drive torque remains TL and TR.

Two single-pinion planetary gear mechanism 30L, 30R is due to the use of gear elements of the same number of teeth, in the velocity diagram, the distance between the ring gear R _L and planet carrier C _L and the ring gear R _R and the planetary carrier the distance between the C _R is equal to the distance "a". Moreover, equally the distance between the sun gear S _L and the distance between the planet carrier C _L and the sun gear S _R and the planetary carrier C _R, is the distance between "b".

Planet carrier _C L, the ring gear from the _{C R R} L, _R length to _R and planet carrier _C L, the sun gear from the _{C R S} L, the ratio of length to _{S R} is the ring gear _R L, the number of teeth of the _{R R} Zr equal the reciprocal of (1 / Zr) and the sun gear _S L, and the ratio of the reciprocal of the number of teeth Zs of _{S R} (1 / Zs). Therefore, a = (1 / Zr) and b = (1 / Zs).

The following formula (5) is calculated from the balance of moment M with reference to the point of R _R. In FIG. 6, the arrow direction M in the figure is the positive direction of the moment.
a * TR + (a + b) * TL- (b + 2a) * TM1 = 0 (5)
The following equation (6) is calculated from the balance of moment M with reference to point _RL .
-A.TL- (a + b) .TR + (b + 2a) .TM2 = 0 (6)

(5) From the formula + (6), the following formula (7) is obtained.
-B. (TR-TL) + (2a + b). (TM2-TM1) = 0
(TR-TL) = ((2a + b) / b). (TM2-TM1) (7)
(2a + b) / b in Expression (7) is the torque difference amplification factor α. When a = 1 / Zr and b = 1 / Zs are substituted, α = (Zr + 2Zs) / Zr, and the following torque difference amplification factor α is obtained.
α = (Zr + 2Zs) / Zr

In this example, the input from the electric motor 2L, 2R (FIG. 5) _is, R L, _{R R,} and the drive wheels 61L, the output of the 61R (FIG. 5) becomes _{S R + C L, S L} + C R.
As shown in FIGS. 5 and 6, when the difference in rotational speed between the first coupling member 31 and the second coupling member 32 is small, the two electric motors 2L and 2R generate different torques TM1 and TM2 and input them. When the torque difference ΔTIN (= (TM1−TM2)) is given, the input torque difference ΔTIN is amplified in the gear device 30, and a driving torque difference α · ΔTIN larger than the input torque difference ΔTIN can be obtained.

That is, even if the input torque difference ΔTIN is small, the input torque difference ΔTIN can be amplified by the torque difference amplification factor α (= (Zr + 2Zs) / Zr) in the gear device 30. Therefore, a driving torque difference ΔTOUT (= α · (TM2−TM1)) larger than the input torque difference ΔTIN can be given to the driving torques TL and TR transmitted to the left driving wheel 61L and the right driving wheel 61R.
In addition, when the rotational speeds of the left and right drive wheels 61L and 61R are equal, relative rotation does not occur in the two coupling elements in the gear device 30, but when the rotational speeds of the left and right drive wheels 61L and 61R are different, the gear device. The two coupling elements in 30 absorb the rotational speed difference between the left and right drive wheels 61L and 61R by causing relative rotation in accordance with the rotational speed difference between the left and right drive wheels 61L and 61R.

<About braking device>
FIG. 7 is a block diagram of a brake control device and the like of the braking device 68.
The braking device 68 includes a friction brake 70 and a brake control device 69. The friction brake 70 includes a braking force drive source 70a that generates a braking force on each wheel, a brake rotor (not shown) that rotates integrally with the wheel, a friction pad, and the like. The braking force drive source 70a includes, for example, a hydraulic drive source provided in a caliper (not shown).

The brake control device 69 controls the braking force drive source 70a based on the brake output command value given from the vehicle control device 66, so that the friction pad contacts and separates from the brake rotor. A braking force is generated on the wheel while the friction pad is in contact with the brake rotor.
The brake control device 69 includes an ABS control unit 72, a normal control unit 73, a command value correction unit 74, and a brake hydraulic pressure control unit 75.

  Each wheel is provided with a rotation speed sensor 71 for detecting the rotation speed of each wheel. The ABS control unit 72 performs antilock brake control based on the brake output command value and the wheel rotation speed received from the rotation speed sensor 71. Specifically, the ABS control unit 72 is a wheel rotation speed that is equal to or less than a predetermined slip ratio for each wheel, and corrects and outputs the brake output command value that makes the wheel rotation speed the ABS target rotation speed. The ABS target rotation speed is calculated from the wheel rotation speed and a predetermined slip ratio. For example, the brake output command value may be corrected by PID control based on the rotation speed of the wheel rotation speed exceeding the ABS target rotation speed. The ABS controller 72 does not correct the brake output command value when the rotational speed of the wheel received from the rotational speed sensor 71 is equal to or higher than the ABS target rotational speed. In other words, the ABS control unit 72 outputs the brake output command value given from the vehicle control device 66 as it is.

  The command value correction unit 74 corrects and outputs the brake output command value given from the ABS control unit 72 when the motor rotation speed received from the vehicle control device 66 increases and exceeds the threshold value. Specifically, the command value correction unit 74 corrects and outputs the applied brake output command value so that the motor rotation speed received from the vehicle control device 66 does not exceed the motor upper limit rotation speed. For example, the brake output command value may be corrected by PID control from the rotational speed corresponding to the motor rotational speed exceeding the motor upper limit rotational speed.

When the received motor rotation speed is equal to or lower than the threshold value, the normal control unit 73 outputs the brake output command value given from the ABS control unit 72 without correction.
The brake hydraulic pressure control unit 75 controls and outputs the brake hydraulic pressure generated by the braking force drive source 70a that drives the friction brake 70 so that the brake output command value given from the command value correction unit 74 or the normal control unit 73 is obtained. To do.

  FIG. 8 is a flowchart showing a braking operation in a certain wheel of the brake control device 69 of FIG. As shown in FIGS. 7 and 8, after the start of this process, first, the ABS control unit 72 compares whether or not the wheel rotational speed is smaller than the ABS target rotational speed (step S1). When the wheel rotation speed is smaller than the ABS target rotation speed (step S1: YES), the ABS control unit 72 calculates a brake output command value A at which the wheel rotation speed becomes the ABS target rotation speed (step S2) and is given. The brake output command value is corrected to the brake output command value A (step S3). When the wheel rotation speed is equal to or higher than the ABS target rotation speed (step S1: NO), the brake output command value is not corrected and the process proceeds to step S4.

Next, the command value correction unit 74 compares whether or not the motor rotation speed of the motor corresponding to the wheel increases and exceeds the threshold value (step S4). When the motor rotation speed increases and exceeds the threshold value (step S4: YES), the command value correction unit 74 calculates a brake output command value B at which the motor rotation speed is equal to or less than the threshold value (step S5). When the calculated brake output command value B is smaller than the brake output command value given from the ABS control unit 72 (step S6: YES), the command value correction unit 74 outputs the given brake output command value as a brake output. The command value is corrected to B (step S7). Thereafter, this process is terminated.
If the motor rotation speed is equal to or lower than the threshold value (step S4: NO), the process ends without correcting the brake output command value. Even when the brake output command value B is equal to or greater than the given brake output command value (step S6: NO), this process is terminated without correcting the brake output command value.

<Effect>
The command value correction unit 74 in the brake control device 69 determines whether any one of the motor rotation speeds increases and exceeds a threshold during braking. The command value correction unit 74 corrects the brake output command value as described above when it is determined that the motor rotation speed increases and exceeds the threshold value.
The torque relational expression between the electric motors 2L and 2R and the left and right wheels 61L and 61R and the relational expression of the rotational speeds of the electric motors 2L and 2R and the left and right wheels 61L and 61R are both influenced by the amplification factor α and the reduction ratio β. Therefore, when the rotational speed of any one of the electric motors 2L (2R) increases and exceeds the threshold value when the vehicle speed decreases, the left and right wheels 61L, The difference in rotational speed of 61R can be reduced, and the rotational speed of the electric motor 2L (2R) can be made lower than the upper limit rotational speed. Therefore, it is possible to prevent over-rotation of the electric motor 2L (2R) and prevent an abnormality of the electric motor 2L (2R).
As described above, the control of the left and right wheel drive device 1 that amplifies the difference in torque between the two electric motors 2L and 2R by the amplification factor α is not performed so as to directly control the rotation speed of the electric motor 2L (2R). Depending on the characteristics, when braking, when the rotational speed of the electric motor 2L (2R) increases and exceeds the threshold value, the rotational speed of the electric motor 2L (2R) is directly limited to perform control to correct the brake output command value. It is possible to reduce the difference between the rotational speeds of the left and right wheels 61L and 61R more easily and reliably than the above, and the rotational speed of the electric motor 2L (2R) can be made equal to or lower than the upper limit rotational speed. Therefore, it is possible to prevent over-rotation of the electric motor 2L (2R) and prevent an abnormality of the electric motor 2L (2R).

<About other embodiments>
In the following description, the same reference numerals are given to portions corresponding to the matters described in advance in the respective embodiments, and overlapping descriptions are omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

FIG. 9 is a block diagram of a brake control device 69A according to another embodiment.
The brake control device 69A includes a command value correction unit 74, a normal control unit 73, an ABS control unit 72, a command value selection unit 76, and a brake hydraulic pressure control unit 75. The command value correction unit 74 sets the brake output command value to the brake output command value so that the motor rotation speed does not exceed the motor upper limit rotation speed when the motor rotation speed received from the vehicle control device 66 increases and exceeds the threshold value. Correct to B and output. The normal control unit 73 outputs the given brake output command value without correction when the received motor rotation speed is equal to or less than the threshold value.

  The ABS control unit 72 performs antilock brake control based on the wheel rotation speed received from the rotation speed sensor 71. Specifically, the ABS control unit 72 corrects and outputs the brake output command value A at which the wheel rotation speed becomes the ABS target rotation speed so that the slip ratio of each wheel becomes a certain fixed value or less.

  In the command value selection unit 76, the brake output command value B output from the command value correction unit 74, the brake output command value output from the normal control unit 73, and the brake output command value A output from the ABS control unit 72 are the smallest. Select and output the command value. For example, when the brake output command value B of the command value correction unit 74 is smaller than the brake output command value A of the ABS control unit 72 or the brake output command value of the normal control unit 73, the command value correction unit 76 corrects the command value. By selecting the brake output command value B of the unit 74, it can be prioritized that the motor rotation speed does not exceed the motor upper limit rotation speed, and as a result, it is agreed that the output of the ABS control unit 72 is corrected. The brake hydraulic pressure control unit 75 controls and outputs the brake hydraulic pressure that drives the friction brake 70 provided in each wheel so that the received brake output command value is obtained.

  FIG. 10 is a diagram showing temporal changes in the rotation speeds of the left and right wheels, the rotation speeds of the left and right electric motors, and the brake output command values of the left and right wheels when the vehicle is braked while traveling at a high speed. is there. The road friction coefficient in this example is low μ for the right driving wheel and high μ for the left driving wheel. In order to simplify the explanation, the reduction ratio β is “1”. In FIG. 10, the vehicle is traveling at a speed close to the motor upper limit rotational speed until time t21.

  Braking is started at time t21, and the brake output command value increases greatly. Although the rotational speed of the driving wheel decreases, the right driving wheel has a low μ road surface and tends to lock, so the rotational speed is greatly decreased. At this time, the rotational speed difference generated between the left and right drive wheels is amplified by the amplification factor α to become the difference between the two motor rotational speeds, and the rotational speed of the right motor is greatly reduced, but the rotational speed of the left motor is increased and time t22. The motor upper limit speed is reached.

  Here, the brake control devices 69 and 69A (FIGS. 1 and 9) reduce the brake output command value of the right drive wheel so that the rotation speed of the left motor is equal to or less than the motor upper limit rotation speed. By reducing the brake output command value for the right drive wheel, the difference in rotation speed between the left and right drive wheels is reduced, and the rotation speed of the left motor is less than or equal to the motor upper limit rotation speed. After time t23, the antilock brake control functions so that the right drive wheel reaches the ABS target rotation speed.

  In the example of FIG. 10, the brake output command value for the right drive wheel, which has a lower rotational speed than the left drive wheel, is corrected. For example, the command value correction unit of the brake control device corrects the brake output command value of the left driving wheel, which has a higher rotational speed than the right driving wheel, to reduce the rotational speed difference between the left and right driving wheels, thereby reducing the left motor driving speed. An increase in rotational speed may be suppressed, or both brake output command values for the left and right drive wheels may be corrected.

In addition, the command value correction unit may set a value lower than the motor upper limit rotation speed as a threshold value, and may correct the brake output command value when the threshold value is exceeded. Thus, by using a value lower than the motor upper limit rotation speed as a threshold value, it is possible to suppress an increase in the motor rotation speed due to a response delay of the friction brake.
The two motor rotation speeds used for the control by the brake control apparatus may be received from the motor control apparatus or the vehicle control apparatus, or may be calculated from the rotation speeds of the left and right drive wheels.

  In each embodiment, the output of the friction brake provided to each wheel is adjusted by the brake control device. However, the regenerative braking force by the motor of the left and right wheel drive device may be used, or may be adjusted in combination with the friction brake. .

In the embodiment shown in FIGS. 2 and 3, to form the planet carrier C _L of the left side of the planetary gear mechanism 30L, a first coupling member 31 is coupled and the sun gear S _R of the right planetary gear mechanisms 30R, left and the sun gear S _L of the planetary gear mechanism 30L for, although the planet carrier C _R of the right planetary gear mechanism 30R form a second coupling member 32 is coupled, but is not limited to this example.

For example, the sun gear S _L of the left side of the planetary gear mechanism 30L, a first coupling member 31 is formed is bonded and the ring gear R _R of the right planetary gear mechanisms 30R, a ring gear R _L on the left side of the planetary gear mechanism 30L it may have a structure in which the sun gear S _R of the right planetary gear mechanism 30R form a second coupling member 32 are coupled.
Other, a planet carrier C _L of the left side of the planetary gear mechanism 30L, may have a structure in which the ring gear R _R of the right planetary gear mechanism 30R form a second coupling member 32 are coupled.

  Needle roller bearings are used as the bearings 45 and 46 between the first and second coupling members 31 and 32. For example, rolling bearings such as deep groove ball bearings and angular ball bearings can also be applied. It is.

  As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... Left-right wheel drive device 2L, 2R ... 1st, 2nd electric motor (driving drive source)
30L, 30R ... Planetary gear mechanisms 61L, 61R ... Drive wheels (wheels)
69, 69A ... Brake control device 70 ... Friction brake (braking force generating means)
70a ... braking force drive source 72 ... ABS control unit 73 ... normal control unit 74 ... command value correction unit

Claims (8)

Two independently driveable drive sources that are controllable, and provided between the two drive sources for driving and the left and right wheels, amplifying a difference in torque applied from the two drive sources for driving, A braking device that brakes each wheel of the vehicle with left and right wheel drive devices that transmit to the wheels, respectively,
Braking force generating means including a braking force drive source for generating a braking force on each wheel;
A brake control device that controls the braking force drive source based on a given brake output command value,
The brake control device includes:
A normal control unit for controlling the braking force drive source so as to have a given brake output command value;
A command value correction unit that corrects brake output command values corresponding to the left and right wheels according to a predetermined condition when the rotational speed of any one of the driving sources for driving increases and exceeds a threshold during braking; Vehicle braking device.   2. The vehicle braking device according to claim 1, wherein the command value correction unit sets the brake output command value so that the increased rotational speed of the driving source for traveling is equal to or less than the threshold as the predetermined condition. 3. Vehicle braking device for correcting   3. The vehicle braking apparatus according to claim 1, wherein the threshold value is determined based on an upper limit rotation speed of the travel drive source. 4.   2. The vehicle braking device according to claim 1, wherein the command value correction unit includes a brake output command corresponding to the left and right wheels so that a difference in rotational speed between the left and right wheels is reduced as the predetermined condition. Vehicle braking device that corrects the value.   The braking device for a vehicle according to any one of claims 1 to 4, wherein the command value correction unit increases a brake output command value corresponding to a wheel having a high rotational speed among the left and right wheels. Or the braking device of the vehicle which correct | amends so that the brake output command value corresponding to a wheel with low rotational speed may be made small.   6. The vehicle braking device according to claim 1, wherein the brake control device performs an anti-lock brake control based on a given brake output command value and the rotational speed of the wheel. A braking device for a vehicle comprising a control unit, wherein the command value correction unit corrects a brake output command value output from the ABS control unit according to a predetermined condition.   The vehicle braking device according to any one of claims 1 to 6, wherein the left and right wheel drive device includes two planetary gear mechanisms. The vehicle braking apparatus according to any one of claims 1 to 7, wherein the traveling drive source is an electric motor.

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