JP2000270405A - Braking device of electric motor car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking device of an electric motor car which can obtain large engine brake feeling which responds to driver's requirement to an accelerator off-step operation when an engine brake range is selected, and prevent sense of uncomfortable braking due to the selection to the engine brake range. SOLUTION: A regenerative braking force generating means e consists of a regenerative braking force generating part e1 when a normal run range is selected, and a regenerative braking force generating means e2, when an engine brake range is selected. The generating part e1 generates a regenerative braking force corresponding to the engine brake on the basis of the accelerator off-step operation, when a detected select position is a normal run range, and generates a regenerative braking force to which a regenerative braking force supplementing hydraulic braking force is added, when the start of a braking operation is detected. The generating part e2 increases regenerative braking force corresponding to the engine brake generated on the basis of the accelerator off-step operation, as compared with the case in which a normal run range is selected, and decreases the regenerative braking force supplementing the hydraulic pressure braking force generated on the basis of a braking operation, when the detected select position is in the engine brake range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a braking device for an electric vehicle applied to a hybrid vehicle using both an engine and an electric motor or an electric vehicle using an electric motor as a prime mover.

[0002]

2. Description of the Related Art Conventionally, as a braking device for an electric vehicle, for example, a braking device described in Japanese Patent Application Laid-Open No. 6-153315 is known.

This publication describes a technique in which a regenerative braking force equivalent to an engine brake is generated when an accelerator is released, and a regenerative braking force that complements the hydraulic braking force is generated when the start of the braking operation is detected.

[0004]

However, in the above-described conventional braking device for an electric vehicle, as shown in FIG. 11, regardless of the selected position of the automatic transmission provided between the electric motor and the driving wheels, Since the control to obtain the regenerative braking force based on the sum of the engine brake equivalent and the hydraulic brake complement is performed, the select position is set to the normal travel range
When performing a select operation to change from the D range) to an engine brake range that requires an engine brake larger than the D range (hereinafter referred to as the L range), even if the accelerator pedal is released in the L range selected state, regenerative braking equivalent to the engine brake is performed. The power is set at the same level as when the D range is selected or at a lower level than when the D range is selected, and there is a problem that a large engine brake desired by the driver cannot be obtained.

That is, when the L range is selected, in a method of increasing the speed ratio of a transmission that is generally performed in a vehicle having only an internal combustion engine, the number of revolutions of the electric motor increases, and the characteristic of the electric motor is increased. However, the allowable regenerative braking force limit value is rather reduced (FIG. 10).
Therefore, during high-speed driving, the number of rotations of the electric motor increases, so that a large amount of regenerative braking force cannot be obtained. In some cases, it may be difficult to secure enough engine brakes.

In order to solve the above-mentioned problem, there is a proposal that a larger regenerative braking force corresponding to the engine brake is taken in the L range selection state than in the D range selection state.

However, in this case, a regenerative braking force, which is obtained by adding a hydraulic brake complement based on a brake operation to a large engine brake, is generated on the drive wheels, so that the control between the drive wheels and the non-drive wheels is generated. The power distribution is remarkably leaning toward the drive wheels, which is different from the braking feeling when the D range is selected, causing a feeling of strangeness in braking. In particular, when the brake operation is performed on a low friction coefficient road (hereinafter, a low μ road) when the L range is selected, a problem such as early locking of the drive wheels occurs due to the distribution of the braking force close to the drive wheels.

The present invention has been made in view of the above problem. When selecting the engine brake range, it is possible to obtain a large engine brake feeling in response to a driver's request for accelerator pedal release operation, and to select the engine brake range. It is an object of the present invention to provide a braking device for an electric vehicle, which can prevent a sense of discomfort due to the selection of the vehicle.

[0009]

According to the first aspect of the present invention,
As shown in the claim correspondence diagram of FIG. 1, a regenerative braking force generating means e for recovering the electric power generated by the electric motor c via the automatic transmission b with the rotation of the wheel a to a vehicle-mounted battery d, and a brake operator f And a hydraulic braking force generating means g for generating a hydraulic braking force in accordance with the operation of the accelerator pedal release operation detecting means h for detecting the accelerator release operation, and starting the braking operation. A braking start switch i for detecting the braking force; and a select position detecting means j for detecting a select position of the automatic transmission b. The regenerative braking force generating means e is operated when the detected select position is in the normal traveling range. A regenerative braking force equivalent to the engine brake is generated based on the releasing operation, and when the start of the braking operation is detected, a regenerative braking force is added to the regenerative braking force that complements the hydraulic braking force. When the line range is selected regenerative braking force generation unit e
1, when the detected select position is in the engine brake range, the regenerative braking force corresponding to the engine brake generated based on the accelerator pedal release operation is increased compared to when the normal travel range is selected, and is generated based on the braking operation. The regenerative braking force is generated by the regenerative braking force generation unit e2 when the emblem range is selected to reduce the regenerative braking force that complements the hydraulic braking force.

According to a second aspect of the present invention, in the brake system for an electric vehicle according to the first aspect, the regenerative braking force generating unit e1 when the engine brake range is selected is used for releasing the accelerator foot when the engine brake range is selected. A regenerative braking force generator that increases only the regenerative braking force equivalent to the engine brake generated based on the normal travel range and complements the hydraulic braking force generated based on the braking operation, and sets the regenerative braking force to zero. It is characterized by having done.

According to a third aspect of the present invention, in the braking device for an electric vehicle according to the first or second aspect, the regenerative braking force generating means e is equivalent to an engine brake that generates based on an accelerator pedal release operation. The regenerative braking force and the regenerative braking force that complements the hydraulic braking force generated based on the braking operation are made to be constant regardless of the selected position of the automatic transmission b.

[0012]

According to the first aspect of the present invention, when the select position detected by the select position detecting means j is in the normal travel range, the regenerative braking force generation unit e1 in the normal travel range selection selects the accelerator. The electric motor c is controlled such that a regenerative braking force equivalent to the engine brake is generated based on the foot release operation, and when the start of the braking operation is detected, a regenerative braking force is generated by adding a regenerative braking force that complements the hydraulic braking force. The electric motor c is controlled as described above. On the other hand, when the select position detected by the select position detecting means j is in the engine brake range, the engine generated based on the accelerator foot release operation in the regenerative braking force generating unit e2 when the emblem range is selected, as compared to when the normal travel range is selected. The regenerative braking force corresponding to the brake is increased, the regenerative braking force that complements the hydraulic braking force generated based on the braking operation is reduced, and the motor c is increased so as to obtain a regenerative braking force that increases one of them and decreases the other. Controlled.

Therefore, when selecting the engine brake range, a regenerative braking force corresponding to the engine brake generated based on the accelerator pedal release operation is increased, so that a large engine brake feeling responding to the driver's request for the accelerator pedal release operation is obtained. In addition to reducing the regenerative braking force that complements the hydraulic braking force generated based on the braking operation, a large difference in the total regenerative braking force is suppressed, and the feeling of discomfort due to the selection of the engine brake range Prevention can be achieved.

According to the second aspect of the present invention, in the regenerative braking force generator e1 when the engine brake range is selected,
When the engine brake range is selected, only the regenerative braking force equivalent to the engine brake generated based on the accelerator pedal release operation is increased compared to when the normal travel range is selected, and the regenerative braking force generated based on the braking operation is supplemented. The braking force is set to zero. Therefore, by adding the regenerative braking force that complements the hydraulic braking force as an increase in the regenerative braking force equivalent to the engine brake, when the engine brake range is selected, the regenerative braking equivalent to the engine brake generated based on the accelerator pedal release operation The power can be set at the maximum increase, and an extremely large feeling of engine braking can be obtained in response to the driver's request for the accelerator release operation.

According to a third aspect of the present invention, in the regenerative braking force generating means e, a regenerative braking force corresponding to an engine brake generated based on an accelerator release operation and a hydraulic braking force generated based on a braking operation. The regenerative braking force control is performed such that the sum of the regenerative braking force and the sum of the regenerative braking force is constant regardless of the selected position of the automatic transmission b. Therefore, when the engine brake range is selected, the regenerative braking force based on the hydraulic brake is further added to the large regenerative braking force based on the accelerator pedal release operation, and the level of the regenerative braking force is increased when the engine brake range is selected compared to when the normal traveling range is selected. In this case, the problem that the braking force is remarkably shifted toward the driving wheel during low-μ road braking and the driving wheel is locked early is solved.

[0016]

(Embodiment 1) Embodiment 1 is a braking device for an electric vehicle according to the first to third aspects of the present invention.

First, the configuration will be described.

FIG. 2 is a diagram showing a regenerative cooperative braking system to which the braking apparatus for an electric vehicle according to the first embodiment is applied. The regenerative cooperative braking system cooperates with a motor regenerative braking with respect to a conventional brake using only hydraulic pressure. This system aims to improve fuel efficiency by controlling brake fluid pressure.

In FIG. 2, 1 is a brake pedal (brake operator), 2 is a hydraulic pressure booster, 3 is a master cylinder, 4 is a brake fluid reservoir, 5 is an external fluid pressure generating unit, and 6 is a regenerative cooperative actuator (fluid). Pressure braking force generating means), 7 is an ABS actuator, 8FR, 8RL, 8RR,
8FL is a wheel cylinder, 12 is a regenerative cooperative control unit, 13 is an ABS control unit, 14 is a motor controller, 15 is an inverter and motor control unit (14 and 15 are regenerative braking force generating means),
16 is a motor (electric motor), 17 is a battery, 18 is a brake switch (brake start switch), 19 and 20 are pressure switches, 21 is a primary master cylinder pressure sensor, 22 is a secondary master cylinder pressure sensor, and 23 is an idle switch (accelerator switch). Foot release operation detecting means), 2
Reference numeral 4 denotes an inhibitor switch (select position detecting means).

The master cylinder 3 increases the pedal depression force applied to the brake pedal 1 by the hydraulic pressure booster 2, and generates a master cylinder pressure corresponding to the pedal depression force.

Each of the wheel cylinders 8FR, 8RL, 8R
The R and 8FL apply a braking force to each wheel according to the wheel cylinder pressure guided from the master cylinder 3 via the regenerative cooperation actuator 6 and the ABS actuator 7.

The regenerative coordination actuator 6 is disposed between the master cylinder 3 and the ABS actuator 7, and when the motor regenerative braking is performed, the braking force obtained by the regenerative braking and the braking to the wheel cylinders 8FR, 8RL, 8RR, 8FL are performed. The master cylinder pressure is reduced so that the sum of the braking force due to the hydraulic pressure matches the required braking force due to the master cylinder pressure.

The ABS actuator 7 includes a regenerative cooperative actuator 6 and wheel cylinders 8FR, 8RL, 8
Each of the wheel cylinders 8FR, 8RL, 8RR, 8RR is arranged between the RR and 8FL so as to suppress the brake lock during low-μ road braking or sudden braking where braking lock occurs.
Controls FL brake pressure.

The regenerative cooperative control unit 12
Is to determine the braking distribution between the regenerative braking force and the hydraulic braking force with respect to the required braking force, and to obtain the determined hydraulic braking force by the brake fluid pressure to each wheel cylinder 8FR, 8RL, 8RR, 8FL. Control means for outputting a valve drive signal to the regenerative coordination actuator 6; a required braking force calculating unit 12a for calculating a required braking force from a master cylinder pressure signal;
A regenerative / hydraulic braking distribution determining unit 1 that determines a braking distribution based on a required braking force and a possible regenerative force from the motor controller 14.
2b, a hydraulic control unit 12c that outputs a valve drive signal based on the determined hydraulic braking distribution, and an FS control unit 12d that monitors the signal and performs fail-safe control.

The ABS control unit 13 includes:
The brake slip state of the wheel is calculated from the wheel speed signal, and a valve drive signal is output to the ABS actuator 7 when it is determined that the brake is locked. The ABS operation signal is A
A control interference prevention measure is output from the BS control unit 13 to the regenerative cooperative control unit 12 to cancel the regenerative cooperative control when the ABS operation is started during braking or the like including during regenerative cooperative control.

The motor controller 14 calculates a possible regenerative braking force at the time of braking and calculates a regenerative / hydraulic braking distribution determining unit 12.
b, the regenerative braking system receives the regenerative power calculating unit 14a, the braking force distribution information from the regenerative / hydraulic braking distribution determining unit 12b, the accelerator OFF signal from the idle switch 23, and the select position signal from the inhibitor switch 24, and performs regenerative braking. It is a controller including a regenerative braking force control unit 14b for controlling the power.

The inverter & motor control unit 15 is a means for controlling a motor including an inverter based on a command from the motor controller 14.

The motor 16 is provided in the drive system in combination with the engine or independently, and functions as a drive motor during running, and a generator (power generation) for storing electricity in the battery 17 by regeneration during braking or deceleration. Machine). Note that an automatic transmission (not shown) is arranged between the motor 16 and the drive wheels.

FIG. 3 is a hydraulic circuit diagram showing a braking device of the electric vehicle according to the first embodiment at the time of normal braking and at the time of electrical failure (F / S). In the regenerative cooperation actuator 6, FCS is a regeneration switching valve, P & RV is a hydraulic control valve, SCC is a common cylinder, CSB is a pressure increasing valve, CSD is a pressure reducing valve, RSV is a reservoir, CHV1 is a first check valve, CHV2 is a second check valve, CHV3 is a third check valve, and BP1 is In the ABS actuator 7, 30FR, 30RL, 30RR, and 30FL are pressure increase control valves, 31FR, 31RL, 31RR, and 31FL are pressure decrease control valves, and 32P and 32S are first bypass fluid paths and BP2 are second bypass fluid paths. Reservoir, 33P, 33S are pumps, 34P, 34S are dampers, 35FR, 35RL, 35R
R and 35FL are check valves.

The regenerative switching valve FCS is provided in the middle of the master cylinder pressure fluid path, so that the master cylinder 3 and the wheel cylinders 8FR, 8RL, 8RR,
This is a 2-position solenoid valve that shuts off the communication of 8FL.

The hydraulic pressure control valves P & RV are provided in parallel with the regenerative switching valve FCS, and each of the wheel cylinders 8FR, 8R has a regenerative pressure reduced during motor regenerative braking.
A valve that creates brake fluid pressure to L, 8RR, 8FL,
Using the master cylinder pressure as an input pressure, a wheel cylinder pressure in which the amount of braking regeneration is reduced by a pressure reduction characteristic obtained by combining a proportioning valve characteristic and a relief valve characteristic is output.

The first check valve CHV1 is provided in the middle of a fluid passage connecting the master cylinder 3 and the regenerative switching valve FCS, and is provided from the master cylinder 3 to each of the wheel cylinders 8FR, 8RL, 8RR and 8FL. Allow distribution only.

The common cylinder SCC is provided in a liquid passage downstream of the first check valve CHV1 and branched from an upstream position of the regenerative switching valve FCS. An absorption cylinder function for absorbing the brake fluid from the master cylinder 3 by the amount of the brake fluid, and a booster for restoring the brake fluid volume to each of the wheel cylinders 8FR, 8RL, 8RR, and 8FL when returning from the motor regenerative braking to the normal braking. The pressure cylinder function is shared by one cylinder. This common cylinder S
CC is a small-diameter cylinder portion on the brake hydraulic pressure chamber side, a large-diameter cylinder portion on the back pressure chamber side, a stepped piston slidably fitted to both cylinders, and a brake hydraulic pressure. A spring biasing in the chamber direction.

The second check valve CHV2 is connected to the first check valve CHV1 and the regeneration switching valve FC.
A first bypass fluid path B that bypasses S and communicates with the master cylinder 3 and each wheel cylinder 8FR, 8RL, 8RR, 8FL.
Provided in the middle of P1, each wheel cylinder 8FR, 8R
Only the flow from L, 8RR, 8FL to the master cylinder 3 is allowed.

The pressure-increasing valve CSB is a normally-open two-position solenoid valve provided in the middle of a fluid path connecting the back pressure chamber of the common cylinder SCC and the hydraulic pressure booster 2. CSD is a normally-closed two-position solenoid valve provided in the middle of a fluid path that connects the back pressure chamber of the shared cylinder SCC and the reservoir RSV, and the third check valve CHV3 is connected to the pressure reducing valve CSD. Bypass reservoir RSV and booster valve CSB
And is provided in the middle of the second bypass fluid passage BP2 that communicates with the fluid passage, and allows only the flow from the reservoir RSV toward the pressure increasing valve CSB. The spring chamber of the reservoir RSV communicates with the brake fluid reservoir 4.

Next, the operation will be described.

[Normal Brake Operation] In the case of normal braking which does not satisfy the motor regenerative braking condition or in the case of fail-safe due to electric failure, each solenoid valve FCS, CSB, CSD of the regenerative cooperation actuator 6 has the solenoid shown in FIG. It is in the OFF position.

Therefore, when the brake operation of depressing the brake pedal 1 is performed, the brake fluid pressure generated in the master cylinder 3 passes through the first check valve CHV1 → the regenerative switching valve FCS → the ABS actuator 7, and is directly changed to the wheel cylinders 8FR, Led to 8RL, 8RR, 8FL,
A braking force is applied to each wheel by a master cylinder pressure (= wheel cylinder pressure).

When the brake is released when the foot is released from the brake pedal 1, the wheel cylinders 8FR, 8RL, 8
The hydraulic pressure of RR and 8FL passes through the ABS actuator 7 → the regenerative switching valve FCS → the first check valve CHV1 and is returned to the master cylinder 3, and the wheel cylinder pressure applied to each wheel is reduced.

[Hydraulic pressure braking operation in regenerative cooperative brake control] Regenerative cooperative control of brake hydraulic pressure by constant braking will be described with reference to FIGS.

When the depression of the brake pedal 1 is started, the brake switch 18 is turned on (BPS in FIG. 5).
Is switched from OFF to ON), based on this switch signal, the regenerative switching valve FCS (ON) is switched from communication to shut off, and the brake fluid pressure generated in the master cylinder 3 passes through the fluid pressure control valve P & RV → ABS actuator 7. Then, the brake fluid is guided to the wheel cylinders 8FR, 8RL, 8RR, and 8FL, and at the fluid pressure control valve P & RV, brake fluid pressure is reduced from the master cylinder pressure by the braking regeneration with the characteristics shown in FIG. Is given a braking force by a wheel cylinder pressure lower than the master cylinder pressure. That is, during normal braking, as shown in FIG. 6A, the master cylinder pressure and the wheel cylinder pressure are 1:
1, the hydraulic pressure control valve P & R
By interposing the V, as shown in FIG. 6 (b), the wheel cylinder pressure to P ₁ is as wheel cylinder pressure to the master cylinder pressure, increase in the master cylinder pressure when the wheel cylinder pressure reaches P ₁ a proportioning valve characteristics wheel cylinder pressure is increased slightly (PV characteristic) with respect to the relief valve characteristic (RV characteristic) of the wheel cylinder pressure is output wheel cylinder pressure that is proportional to the master cylinder pressure becomes a P ₂ or more and a synthetic Due to the reduced pressure characteristics, the wheel cylinder pressure in which the amount of braking regeneration (dotted area in FIG. 6) is reduced is output. This braking regenerative amount is determined according to the calculation result of the regenerative / hydraulic braking distribution in the regenerative cooperative control unit 12.

As described above, during the motor regenerative braking, the communication between the master cylinder 3 and each of the wheel cylinders 8FR, 8RL, 8RR, 8FL is cut off by the regenerative switching valve FCS.
The hydraulic pressure control valve P & RV generates a brake hydraulic pressure in which the amount of the brake regeneration is reduced. Therefore, each of the wheel cylinders 8 out of the brake fluid from the master cylinder 3
It is necessary to absorb as much brake fluid as the amount of fluid consumed in FR, 8RL, 8RR, and 8FL has decreased. On the other hand, as shown in FIG. 5, when the depression of the brake pedal 1 is started, first, the pressure increasing valve CSB is closed in response to the ON of the brake switch 18, and immediately thereafter, the hydraulic pressure control valve P
The pressure reducing valve CSD is opened in response to the start of the pressure reduction of & RV. Therefore, the brake fluid from the master cylinder 3
Shared cylinder SC via first check valve CHV1
C, the stepped piston of the common cylinder SCC is pushed to store the brake fluid pressure in the brake fluid pressure chamber, and the pressure is reduced from the back pressure chamber (equivalent to atmospheric pressure) of the common cylinder SCC to the pressure reducing valve CSD.
After that, the brake fluid is stored in the reservoir RSV, whereby the absorption cylinder function is exhibited.

When returning from the motor regenerative braking to the normal braking, the shutoff between the master cylinder 3 and each of the wheel cylinders 8FR, 8RL, 8RR, 8FL is released by the regenerative switching valve FCS, and both cylinders 3, 8FR, 8RL, 8RR, 8FL
Is communicated. At this time, since the brake fluid in each of the wheel cylinders 8FR, 8RL, 8RR, 8FL is insufficient due to the absorption of the brake fluid and the fluid pressure is low, the wheel cylinder pressure is increased to the master cylinder pressure level. There is a need. On the other hand, as shown in FIG. 5, first, when the hydraulic pressure control valve P & RV reaches the relief valve operating pressure, the pressure reducing valve CSD is closed at a later point in time, and the pressure increasing valve CSB is opened with some time delay. . Therefore, when the regenerative switching valve FCS is switched to the communication side at the end of the regenerative cooperation, the brake fluid of the shared cylinder SCC having the boost pressure as the back pressure is supplied to the first check valve CHV.
1, the wheel cylinders 8FR, 8FR do not flow into the master cylinder 3 side but through the regeneration switching valve FCS.
Each wheel cylinder 8FR, 8RL, 8RR, 8FL which is sent to RL, 8RR, 8FL to restore the brake fluid volume and decompress
Is increased to the level of the master cylinder 3, and the pressure increasing cylinder function is exhibited.

FIG. 7 is a flowchart showing the flow of the regenerative braking force control operation performed by the motor controller 14. Each step will be described below (corresponding to regenerative braking force generating means).

In step 70, the idle switch 23
It is determined whether or not the accelerator OFF signal is input from the controller.

In step 71, it is determined from the select position signal from the inhibitor switch 24 whether the select position of the automatic transmission is the D range position.

In step 72, the brake switch 18
It is determined whether the switch signal from is an ON signal.

In step 73, the accelerator is determined to be OFF in step 70, the D range is determined in step 71, and when the brake is determined to be OFF in step 72, a regenerative braking force corresponding to the engine brake (0.04G) is generated. Command to do is inverter & motor control unit 15
Is output to

In step 74, when the accelerator is determined to be OFF in step 70, the D range is determined in step 71, and when the brake is determined to be ON in step 72, the hydraulic pressure is applied to the regenerative braking force for the engine brake (0.04G). A command to generate a regenerative braking force to which the complement (0.04 G) is added is output to the inverter & motor control unit 15. Steps 73 and 74 correspond to a regenerative braking force generation unit when the normal traveling range is selected.

At step 75, it is determined from the select position signal from the inhibitor switch 24 whether the select position of the automatic transmission is the L range position.

In step 76, it is determined in step 70 that the accelerator is off, in step 71 it is determined that the engine is not in the D range, and when it is determined in step 75 that it is in the L range, the regenerative braking force for the engine brake (0.08G) is applied. The generated command is output to the inverter & motor control unit 15. Step 76 corresponds to a regenerative braking force generation section when the engine brake range is selected.

[Generation of regenerative braking force in D range] When the accelerator pedal is released with the D range selected, step 70 → step 71 → in the flowchart of FIG.
The flow proceeds from step 72 to step 73. In step 73, the motor is controlled so as to generate the regenerative braking force corresponding to the engine brake (0.04G).

After the accelerator is released, when the brake operation is performed by depressing the brake pedal 1, in the flowchart of FIG.
→ The flow proceeds to step 72 → step 74. In step 74, the engine brake amount (0.04 G) +
The motor is controlled so as to generate the regenerative braking force corresponding to the hydraulic pressure supplement (0.04 G).

That is, as shown in FIG. 8, an engine brake of about 0.04 G is operated by the motor regenerative braking based on the accelerator release operation. When the brake operation is performed, motor regenerative braking corresponding to the hydraulic brake complement is applied so as to complement the hydraulic brake reduced in pressure as described above.

[Generation of regenerative braking force in L range] At the time of accelerator release operation with the L range selected, in the flowchart of FIG.
The flow proceeds from step 75 to step 76. At step 76, the motor is controlled so as to generate the regenerative braking force corresponding to the engine brake (0.08G).

That is, as shown in FIG. 9, a large engine brake of about 0.08 G works by the motor regenerative braking based on the accelerator foot releasing operation, and a high feeling of emblem is obtained. Even if a brake operation is performed, the regenerative braking force equivalent to the engine brake and the regenerative braking force corresponding to the hydraulic brake supplement are set in advance, so that the total regenerative braking force does not change depending on the presence or absence of the brake operation.

Next, the effects will be described.

(1) At the time of accelerator release operation with the L range selected, about 0.08 G (twice that when the D range is selected)
Motor regenerative braking with large
When selecting the range, it is possible to obtain a large feeling of engine braking that responds to the driver's request when the accelerator is released.

(2) The motor regenerative braking based on the accelerator foot release operation is increased from that in the D range. However, even if the brake operation is performed, the motor regenerative braking for the hydraulic brake complement is more converse than in the D range. Since the difference is reduced, the difference in the total braking force between when the D range is selected and when the L range is selected is suppressed to a small value.
The feeling of strangeness in braking when selecting the range is eliminated.

(3) When the L range is selected, only the regenerative braking force corresponding to the engine brake generated based on the accelerator pedal release operation is increased as compared to when the D range is selected, and the hydraulic pressure generated based on the braking operation Since the regenerative braking force for the brake supplement is set to zero, the regenerative braking force (0.04 G) for the hydraulic brake supplement is equivalent to the engine brake, for example, even if a condition for keeping the total regenerative braking force constant is imposed. The regenerative braking force can be added as an increase in the regenerative braking force, and when the L range is selected, the regenerative braking force corresponding to the engine brake generated based on the accelerator release operation can be set with the maximum increase allowance, and the accelerator release operation In contrast, an extremely large feeling of engine braking that meets the driver's requirements can be obtained.

(4) The sum of the regenerative braking force x (= 0.04 G) corresponding to the engine brake when the D range is selected and the hydraulic brake supplement y (= 0.04 G) when the D range is selected, and L
X + y (= 0.
08G) and the regenerative braking force is constant regardless of the selected position. Therefore, when the L range is selected, the regenerative braking force for the hydraulic brake supplement is further added to the large regenerative braking force based on the accelerator pedal release operation. In addition, the problem that the braking force becomes remarkably closer to the driving wheels during low μ road braking and the driving wheels are locked early is also solved.

(Other Embodiments) In the first embodiment, L
In the preferred range, only the amount equivalent to the engine brake is increased at the time of the range, the supplementary value of the hydraulic brake is set to zero, and the engine braking effect is maximized when the accelerator pedal is released in the L range selection. An example in which the amount corresponding to the brake is increased from the time of the D range, and the amount corresponding to the hydraulic pressure brake is decreased from the time of the D range in response to the increase.

In the first embodiment, a preferable example is shown in which the driving wheel early lock can be prevented by keeping the total regenerative braking force constant regardless of the L range selection or the D range selection. There may be a slight difference in the regenerative braking force between the range selection and the total regenerative braking force so that the total regenerative braking force does not have a sense of strangeness in braking.

[Brief description of the drawings]

FIG. 1 is a view corresponding to a claim showing a braking device for an electric vehicle according to the present invention.

FIG. 2 is a diagram of a regenerative cooperative braking system to which the braking device for the electric vehicle according to the first embodiment is applied.

FIG. 3 is a diagram showing a normal braking and electric failure (F
FIG. 3 is a hydraulic circuit diagram showing the braking device for the electric vehicle at the time of (/ S).

FIG. 4 is a hydraulic circuit diagram showing a braking device for the electric vehicle during regenerative cooperation according to the first embodiment.

FIG. 5 is a time chart for explaining each operation state in regenerative cooperative control at the time of constant braking by the braking device for the electric vehicle according to the first embodiment.

FIG. 6 is a diagram showing pressure reduction characteristics of a hydraulic pressure control valve employed in the braking device for the electric vehicle according to the first embodiment.

FIG. 7 is a flowchart showing a flow of a regenerative braking force control operation performed by the motor controller according to the first embodiment.

FIG. 8 is a characteristic diagram of regenerative braking force by regenerative braking force control in a D range in the braking device for the electric vehicle according to the first embodiment.

FIG. 9 is a characteristic diagram of a regenerative braking force by regenerative braking force control in an L range in the braking device for the electric vehicle according to the first embodiment.

FIG. 10 is a characteristic diagram of a regenerative braking force with respect to a motor speed.

FIG. 11 is a characteristic diagram of regenerative braking force by regenerative braking force control in a D range and an L range in a conventional braking device for an electric vehicle.

[Explanation of symbols]

 a wheel b automatic transmission c electric motor d battery e regenerative braking force generating means e1 regenerative braking force generating section when normal driving range is selected e2 regenerative braking force generating section when selecting emblem range f brake operator g hydraulic braking force generating means h accelerator foot Release operation detecting means i Braking start switch j Select position detecting means

Claims (3)

[Claims] 1. A regenerative braking force generating means for recovering electric power generated by an electric motor through an automatic transmission with a rotation of a wheel to a vehicle-mounted battery, and a liquid for generating a hydraulic braking force in response to an operation of a brake operator. Pressure braking force generating means, and a braking device for an electric vehicle, comprising: an accelerator release operation detecting means for detecting an accelerator release operation; a braking start switch for detecting a start of a braking operation; and a select position of the automatic transmission. A regenerative braking force generating means for generating a regenerative braking force equivalent to an engine brake based on an accelerator pedal release operation when the detected select position is in a normal traveling range. A regenerative braking force generator when a normal driving range is selected, which generates a regenerative braking force by adding a regenerative braking force that complements the hydraulic braking force when the start of operation is detected; When the selected position is in the engine brake range, the regenerative braking force equivalent to the engine brake generated based on the accelerator pedal release operation is increased compared to when the normal travel range is selected, complementing the hydraulic braking force generated based on the braking operation. A braking device for an electric vehicle, characterized in that the regenerative braking force is reduced by means of a regenerative braking force generation unit when an engine brake range is selected. 2. The braking device for an electric vehicle according to claim 1, wherein the regenerative braking force generating unit when the engine brake range is selected is equivalent to an engine brake that is generated based on an accelerator foot release operation when an engine brake range is selected. Only the regenerative braking force of the normal driving range is increased,
A braking device for an electric vehicle, wherein a regenerative braking force generating unit that makes a regenerative braking force complementary to a hydraulic braking force generated based on a braking operation zero is provided. 3. The braking device for an electric vehicle according to claim 1, wherein said regenerative braking force generating means generates a regenerative braking force corresponding to an engine brake generated based on an accelerator pedal release operation.
A braking device for an electric vehicle, characterized in that a sum of a hydraulic braking force generated based on a braking operation and a regenerative braking force is constant regardless of a selected position of the automatic transmission.