JPH07205800A - Brake device for electric vehicle - Google Patents

Abstract

PURPOSE:To provide a brake device having a sure failsafe operation, simplifying a device constitution and further improving energy recovery and brake feeling. CONSTITUTION:In accordance with turning off an accelerator without waiting for stepping in a brake pedal 22, a control signal is given to a hydraulic pressure valve 54 to control its opening value Po to a sufficiently high value. In this hydraulic pressure value 54, in its control-off condition, an oil pressure in a master cylinder 26 (M/C pressure) is transmitted to a front wheel cylinder 28. By only operating off-control, a sure failsafe operation can be realized, to simplify a device constitution. Since braking is started without delay from the M/C pressure, energy recovery and brake feeling are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle braking device for braking an electric vehicle by hydraulic braking and regenerative braking.

[0002]

2. Description of the Related Art As a vehicle braking device, a hydraulic pressure (generally hydraulic pressure) generated in response to a braking operation of a vehicle operator.
A hydraulic (hydraulic) braking device that transmits the braking force to the wheel side for braking is generally used. Further, in an electric vehicle, the vehicle can be braked by regenerating electric power with a vehicle driving motor. In an electric vehicle, these hydraulic (hydraulic) braking and regenerative braking can be used together.

The braking force in the hydraulic (hydraulic) braking and the regenerative braking can be controlled. That is,
The hydraulic (hydraulic) braking force can be controlled by providing a valve such as a solenoid valve on the liquid passage (oil passage), and the regenerative braking force can be controlled by controlling the power conversion operation. Therefore, in an electric vehicle equipped with both of these two types of braking means, a braking device capable of controlling both hydraulic (hydraulic) braking force and regenerative braking force can be configured. Conventionally, such control has been variously studied from the viewpoint of optimization of braking force distribution and improvement of brake feeling.

FIG. 12 shows the structure of a braking device according to a conventional example. The apparatus shown in this figure is disclosed in
This is a configuration in which the device disclosed in Japanese Patent No. 161211 is partially simplified or modified.

A member indicated by reference numeral 10 in this figure is an AC motor for driving a vehicle. The output shaft of the motor 10 is connected to a drive shaft 12 that is connected to drive wheels (front wheels in this case). In addition, the motor 10
Is driven to rotate by receiving power supply from a vehicle-mounted battery 16 via an inverter 14. The inverter 14 responds to the control signal supplied from the motor ECU 18 to the battery 1
The discharge power (DC power) of 6 is converted into AC power and supplied to the motor 10.

The motor ECU 18 constitutes means for controlling the output torque of the motor 10 together with the inverter 14. For example, when powering the motor 10, the motor EC
U18 inputs a signal indicating the depression amount of the accelerator pedal and a signal indicating the rotation speed of the motor 10, and controls the power conversion operation in the inverter 14 based on these signals. As a result, the output torque can be obtained from the motor 10 according to the depression amount of the accelerator pedal.

The motor ECU 18 constitutes a regenerative braking means together with the regenerative ECU 20 and the like. That is, when the pedaling force sensor 24 detects that the brake pedal 22 has been stepped on, the regenerative ECU 20 starts the regenerative braking control accordingly. When performing regenerative braking control, the regenerative ECU 2
0 communicates with the motor ECU 18. Motor ECU 18
Represents the pedaling force sensor 2 according to the result of communication with the regenerative ECU 20.
The regenerative output torque of the motor 10 is controlled so that the battery 16 regenerates the braking energy corresponding to the pedaling force detected by 4.

The hydraulic braking means is a master cylinder (hereinafter,
M / C) 26 to front (hereinafter, Fr) wheel cylinder (hereinafter, W / C) 28 and rear (hereinafter, Rr) W /
It is constituted by an oil passage arranged over C30. The M / C 26 generates hydraulic pressure (hereinafter referred to as M / C pressure) according to the amount of depression of the brake pedal 22, and the generated hydraulic pressure is applied to the FrW / C 28 and RrW / C via the differential pressure valve 32 or 34.
Supply to 30. FrW / C28 and RrW / C30
Are provided to apply hydraulic pressure (hereinafter, W / C pressure) to the Fr brake rotor 36 and the Rr brake rotor 38, respectively. Therefore, when the differential pressure valves 32 and 34 are opened, the hydraulic braking force acts on each of the wheels Fr and Rr. In the figure, 39 is a reservoir tank.

[0009]

The device of this prior art is as follows.
It is possible to operate so that the response of the braking torque to the M / C pressure has a linear characteristic. In that case, the operation of each part is as follows. First, the regenerative ECU 20 detects the state of the battery 16 using the sensor 40 attached to the battery 16. For example, the remaining capacity and temperature of the battery 16 are detected. The regenerative ECU 20 determines the regenerative ability based on the detection result. For example, it is determined that the regenerative ability is large when the battery 16 is being discharged, and it is determined that the regenerative ability is small when the battery 16 is close to full charge.

The regenerative ECU 20 determines the valve opening value P ₀ of the differential pressure valves 32 and 34 in accordance with the regenerative capacity thus determined. The differential pressure valve 32 includes a spring 42 and a linear solenoid 44, and the differential pressure valve 34 includes a spring 46.
And the linear solenoid 48, respectively, and the valve opening value P ₀ can be controlled by the drive control of the linear solenoids 44 and 48. Regenerative ECU 2
When 0, the regenerative braking control is performed according to the M / C pressure and in cooperation with the motor ECU 18, while the differential pressure valves 32 and 34 are opened at the M / C pressure at which the braking energy related to the regenerative braking reaches the maximum value E. , Linear solenoids 44 and 4
8 to set the valve opening value P ₀ .

As a result of such control, braking energy as shown in FIG. 13 is generated in regenerative braking and hydraulic braking, and as shown in FIG.
A braking torque that is linear with respect to pressure is realized. Such characteristics contribute to improving the brake feeling.

Further, by performing such control,
It is also possible to deal with the case where the regenerative ability to the battery 16 changes. That is, in the above-described control, when the regenerative ability is reduced and the maximum braking energy related to regeneration is reduced from E to E ′ as shown in FIG. 15, the M / C pressure at which the hydraulic braking force starts to act, that is, The valve opening values of the differential pressure valves 32 and 34 are set to P corresponding to the decrease in the maximum braking energy related to regeneration.
_{Since the} change control from ₀ to P ₀ ′ can be performed, a good brake feeling can be maintained regardless of the change in the regenerative ability, unless the regenerative ability is significantly reduced as described later.

In the above-mentioned conventional example, the differential pressure valves 32 and 3 are provided.
The variable setting of the valve opening value P ₀ in 4 is performed by adjusting the load of the spring 42 or 46 using the linear solenoids 44 and 48. This differential pressure valve 3
At 2 and 34, the spring 42 or 46 has some preset load. That is, in this conventional example, even if the M / C pressure P _{M / C} is generated, the M / C pressure P _{M / C} does not exceed the value corresponding to the preset load of the spring 42 or 46. / C pressure P _{M / C}
Is not transmitted to W / Cs 28 and 30. Even if there is a delay in the supply of the control signal (driving current) from the regenerative ECU 20 during braking due to the delay in transmission of the M / C pressure P _{M / C to} the W _{/ Cs} 28 and 30, a differential pressure is preferably generated during that delay. be able to. That is, the vehicle operator controls the brake pedal 22.
Until the control signal (drive current) from the regenerative ECU 20 is supplied to the differential pressure valves 32 and 34 and the valve opening pressure is set to a predetermined value after stepping on, the W of the M / C pressure P _{M / C} is set.
Since the transmission to the C / Cs 28 and 30 is cut off, the M / C pressure P _{M / C} is not transmitted to the W / _Cs 28 and 30 simultaneously with the depression of the brake pedal 22. However,
This appears as a response delay Δp ₀ of the hydraulic braking force when the vehicle operator depresses the brake pedal 22.

Such a response delay is not preferable especially when the regenerative braking fails (when some abnormality occurs in the regenerative braking function and the regenerative braking cannot be performed). That is, if the action of the hydraulic braking force is delayed while the regenerative braking is failing, the appropriate braking cannot be achieved. Also, the corresponding differential pressure valve 32 or 34 may fail. Therefore, in this conventional example, fail-safe solenoid valves 50 and 52 are provided in parallel with the differential pressure valves 32 and 34. These solenoid valves 50 and 52 normally shut off the M / C pressure,
The regeneration ECU 20 controls to open and transmit the M / C pressure as it is during a failure. With such a configuration and control, in the conventional example, it is possible to appropriately cope with a failure.

As described above, by applying the configuration of the conventional example, it is possible to realize a good brake feeling and to cope with a regenerative fail. However, two solenoid valves 50 and 52 are provided to handle the failure.
Is required, and the device configuration becomes complicated. Further, when the regenerative ability is very low and the M / C pressure at which the regenerative braking torque reaches the maximum is smaller than the preset load Δp ₀ of the springs 42 and 46, as shown in FIG. 17, the M / C pressure versus the braking torque. This causes a step in the characteristics, which makes the brake instability unstable and deteriorates the brake feeling.

The present invention has been made to solve the above problems, and compensates for the response delay of the valve opening pressure control of the differential pressure valve to eliminate the preset load setting, thereby regenerating the regeneration. An object of the present invention is to realize a braking device that can obtain a stable braking ability and a good brake feeling even when the ability is very small. Another object of the present invention is to realize a device that does not require a solenoid valve for dealing with a fail and has a simple device configuration, a small size, and a light weight.

[0017]

In order to achieve such an object, the present invention provides a vehicle operator having a valve for generating a differential pressure before and after it according to the value of a hydraulic pressure control signal supplied. The hydraulic pressure braking means for reducing the hydraulic pressure generated in response to the brake operation by this differential pressure and then acting as hydraulic braking force, and the electric power corresponding to the value of the regeneration control signal are regenerated by the vehicle driving motor. To generate a hydraulic pressure control signal and a regenerative control signal so that the regenerative braking means that applies the regenerative braking force and the braking force of the hydraulic braking force and the total regenerative braking force have a predetermined relationship to the braking operation of the vehicle operator. A braking control means for braking an electric vehicle with a hydraulic braking force and a regenerative braking force, the braking control means responding to a stop of an accelerator operation by a vehicle operator and prior to the start of the brake operation. Characterized by preparing to produce a hydraulic pressure control signal.

Further, according to the present invention, when the hydraulic braking means is not supplied with the hydraulic pressure control signal, the hydraulic pressure generated by the vehicle operator in response to the brake operation is generated without generating the differential pressure by the valve. It is characterized in that it acts as a hydraulic braking force.

[0019]

In the present invention, the hydraulic control signal is generated in response to the accelerator operation of the vehicle operator being stopped and prior to the start of the brake operation. The valve of the hydraulic braking means generates a differential pressure according to the value of the hydraulic control signal supplied. Therefore,
At the time when the brake operation is started, the hydraulic braking means is
The valve has already reached a state where the necessary differential pressure can be generated. Therefore, in the present invention, it is not necessary to use a structure in which the load of the spring is adjusted by the solenoid as the valve for generating the differential pressure. this is,
This means that the spring can be eliminated and therefore the delay due to its preset load can be eliminated,
As a result, a stable braking ability and a good brake feeling can be obtained even when the regeneration ability is very small.

Further, in the present invention, when the hydraulic pressure control signal is not supplied, the hydraulic pressure generated according to the brake operation of the vehicle operator acts as the hydraulic braking force as it is. That is, the valve does not generate a differential pressure in this state. Therefore, even if the other part of the braking device fails, the hydraulic braking force acts without delay in response simply by cutting off the supply of the hydraulic pressure control signal, so that a reliable fail-safe is realized. At that time, since a solenoid valve for dealing with a fail is not necessary, the device configuration is simple, small, and lightweight.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. The same components as those in the conventional example shown in FIGS. 12 to 17 are designated by the same reference numerals, and the description thereof will be omitted.

Configuration of First Embodiment FIG. 1 shows the configuration of a braking system according to the first embodiment of the present invention. In this embodiment, a hydraulic valve 54 is provided in place of the differential pressure valve 32 and the failsafe solenoid valve 50 in the conventional example. The hydraulic valve 54 is a valve that is controlled by the regenerative ECU 20 during braking, and has a pressure increasing side poppet valve and a pressure reducing side poppet valve, as will be described later. The hydraulic valve 54 opens when the M / C pressure P _{M / C} exceeds the valve opening value P ₀ given by the regenerative ECU 20. That is, M / C
It opens when the difference between the W / C pressures of pressure P _{M / C} and FrW _{/ C} 28 exceeds P ₀ . On the contrary, when the M / C pressure P _{M / C} does not exceed the valve opening value P ₀ , it is closed and the M / C
The oil passage from 26 to FrW / C28 is shut off. Further, when the control by the regenerative ECU 20 is not performed (OFF state), the hydraulic valve 54 transmits the M / C pressure to the FrW / C 28 almost as it is.

Further, in this embodiment, a P valve 56 is provided instead of the differential pressure valve 34 and the failsafe solenoid valve 52 in the conventional example, and M /
The hydraulic pressure generated at C26 is transmitted to the RrW / C30 via the P valve 56.

Further, a stroke simulator 58 is arranged between the M / C 26 and the hydraulic valve 54.
The stroke simulator 58 consumes an amount of oil so that the pedal stroke of the brake pedal 22 becomes natural with the hydraulic valve 54 blocking the oil passage from the M / C 26 to the FrW / C 28. M / C26
A hydraulic sensor 60 is further provided between the hydraulic valve 54 and the hydraulic valve 54.
_{M / C} is detected. The detected M / C pressure P _{M / C} is supplied to the motor ECU 18 and is supplied to the motor 10 during regenerative braking.
It is used to control the output torque (regenerative torque) of P to the value according to the M / C pressure P _{M / C.}

Further, the regenerative ECU 20 inputs information indicating the state of the battery 16, and judges the regenerative ability for the battery 16 based on the information. While the regenerative ECU 20 sets the valve opening value P ₀ of the hydraulic valve 54 according to the determination result,
The motor ECU 18 is notified of the maximum regenerative torque (torque corresponding to the regenerative ability) T ₀ . Motor ECU 18
Controls the output torque of the motor 10 with the maximum regenerative torque T ₀ as the upper limit. The information indicating the state of the battery 16 is obtained by the battery ECU 62 that calculates the state of charge of the battery 16 and the like.

The regenerative ECU 20 detects by the throttle sensor 64 that the accelerator has been turned off by the vehicle operator, and starts controlling the hydraulic valve 54 accordingly. The first feature of the present embodiment is that the control of the hydraulic valve 54 is started in response to the accelerator off without waiting for the start of depression of the brake pedal 22.

Operation of the First Embodiment FIG. 2 shows the flow of the operation of the motor ECU 18 and the regenerative ECU 20 in this embodiment, especially the operation during braking. In this figure, the motor ECU 18 and the regenerative E
Although the sharing of CU 20 is not shown, which ECU is in charge of which function can be determined by design.

The routine shown in this figure is started by using the detection result of the throttle sensor 64 as a trigger. That is, the throttle sensor 6 indicates that the accelerator has been turned off.
Until detected by 4 (100), this routine is left unexecuted and returns to the main routine. In that case,
The hydraulic valve 54 is turned off, that is, the regenerative ECU 20.
It is kept in a state not controlled by (102). When the hydraulic valve 54 is off, W of FrW / C28
The / C pressure becomes the M / C pressure P _{M / C.}

When the throttle sensor 64 detects that the accelerator is off (100), the motor 10
The rotational speed N of is compared with the regenerative braking start rotational speed N _lim (104). The regenerative braking start rotation speed N _lim refers to the lowest rotation speed at which regenerative braking can be started, as shown in FIG. Therefore, when the result of this comparison is N <N _lim , regenerative braking cannot be performed, so this routine is not executed and the routine returns to the main routine. In this state,
Only hydraulic braking is possible.

On the contrary, when it is judged that N ≧ N _lim , the maximum regenerative torque T ₀ is determined (106). The maximum regenerative torque T ₀ refers to the maximum regenerative torque that can be generated by the motor 10, as shown in FIG. Therefore, the regenerative ECU
The control range of the valve opening value P ₀ of the hydraulic valve 54 by 20 is
The pressure corresponding to the maximum regenerative torque T ₀ cannot be exceeded, and the control range of the regenerative torque by the motor ECU 18 is also determined by the maximum regenerative torque T ₀ . Maximum regenerative torque T
_{When 0} is determined, the pressure corresponding to this is subsequently determined (108), and the determined pressure is set to the valve opening value P ₀ of the hydraulic valve 54 (110). By this control, the hydraulic valve 54 is brought into a controllable state without a response delay before the depression of the brake pedal 22 is started.

Next, whether the brake pedal 22 is depressed or not is determined by the output of the hydraulic pressure sensor 60, which is the M / C pressure P.
It is determined based on _{M / C} (112). As a result, when it is determined that the brake pedal 22 is not yet depressed, the regenerative braking control is not performed and the routine is finished (114). In this case, braking is not performed because the hydraulic pressure is also cut off.

On the contrary, when it is judged that the brake pedal 22 is depressed, the regenerative torque T corresponding to the M / C pressure P _{M / C} is calculated (116), and the inverter 14 is operated according to the regenerative torque T. Controlled (118). On the other hand, the regenerative ability is determined based on the information output from the battery ECU 62, the valve opening value P ₀ is determined accordingly (120), and this valve opening value P ₀ is set in the hydraulic valve 54. (122). After this, the routine shown in the figure ends.

When such control is performed, the total braking energy of the front wheels and the rear wheels has the characteristic shown in FIG. That is, when the M / C pressure P _{M / C} is lower than the valve opening value P _0, only the regenerative braking force acts on the front wheels, and when the M / C pressure P _{M / C} is high, the regenerative braking force becomes maximum while the hydraulic valve 54
The hydraulic braking force via starts to act. Further, on the rear wheel side, the hydraulic braking force via the P valve 56 is increased by the M / C pressure P.
_It operates even when _{M / C} is lower than the valve opening value P ₀ .

Further, according to such control, the hydraulic valve 54 becomes controllable prior to the start of depression of the brake pedal 22. Therefore, even if the hydraulic valve 54 has a response delay, this response delay The effect of can be eliminated. Therefore, since it is not necessary to set a preset load on the hydraulic valve 54, stable braking characteristics without a step and a good brake feeling can be obtained even when the regenerative ability is very small. Since the improvement of the braking characteristic leads to the improvement of the energy recovery efficiency to the battery 16,
The vehicle travelable distance per charging the battery 16 once is extended, and the electric vehicle is highly usable.

Further, in order to cope with a failure, solenoid valves 50 and 52 must be provided in the conventional example. On the other hand, in the present embodiment, it is not necessary to provide this kind of valve, and the simplification, downsizing and weight saving of the device configuration can be realized. That is, since it is not necessary to set the preset load, the M / C pressure P _{M / C} is transmitted to the FrW / _C 28 simply by turning off the hydraulic valve when regeneration is failing. Further, even if the drive mechanism of the hydraulic valve 54 itself (coil described later) fails, the hydraulic valve 54 is opened by the M / C pressure P _{M / C in a} state where it is not controlled. Works.

Further, in the present embodiment, step 10
8, the valve opening value P ₀ is determined according to the maximum regenerative torque T ₀ . However, it is not always necessary to set and control to a value equivalent to the maximum regenerative torque T _0, and it is sufficient to control to a pressure sufficiently high with respect to the response delay of the hydraulic valve 54. Of course, the higher the value as in this embodiment, the better the effect of response delay can be eliminated. Further, also in this embodiment, similarly to the conventional example, it is possible to cope with the change in the regenerative ability by controlling the valve opening value P ₀ . In addition, since the hydraulic valve 54 is not always energized, power consumption is low.

Structure of Hydraulic Valve FIG. 5 shows a hydraulic valve 54 usable in this embodiment.
An example configuration is shown. The hydraulic valve 54 shown in this figure does not have a structure for adjusting the load of the spring by a solenoid, unlike the differential pressure valves 32 and 34 of the conventional example. In this figure, the hydraulic valve 54 is
The closed state is maintained until the C pressure P _{M / C} exceeds the valve opening value P ₀ given by the regenerative ECU 20, and when it exceeds, the M / C pressure P _{M / C} and the W / C pressures of the FrW / _C 28 are opened. It has a booster side poppet valve 66 configured to control to a valve value P ₀ . That is, the valve opening value P ₀ is determined by the balance between the force due to the M / C pressure P _{M / C} applied to the pressure increasing side poppet valve 66 and the force according to the valve opening value P ₀ given by the regenerative ECU 20. . Hydraulic valve 54
M / C pressure P _{M / C} is FrW / C28 W /
When the pressure becomes lower than the C pressure, the W / C pressure of the opening FrW / C 28 is reduced, while the pressure reducing side poppet valve 68 is closed in other states.

The hydraulic valve 54 has a structure in which housings 72 and 74 are fixed to the left and right ends of the core 70 made of a magnetic material in the drawing by bolts and nuts. A shaft 76 penetrates through the core 70 in a slidable state. A plunger 78 made of a magnetic material is fixed around the shaft 76, and a coil 80 is embedded in the core 70 close to the plunger 78. The coil 80 is sealed by the member 82. Therefore, when a current flows in the coil 80 in a predetermined direction, a force in the left direction in the drawing acts on the plunger 78, and thus the shaft 76.

The pressure increasing side poppet valve 66 is provided on the left side of the shaft 76 in the figure. The valve chamber 86 of this valve 66 is
The oil passage from the M / C 26 communicates with the M / C port 84 provided in the housing 72. A ball 88 is accommodated in the valve chamber 86 as shown in an enlarged view in FIG. Therefore, when the M / C pressure P _{M / C} is generated, a rightward force P _{M / C} · A in the figure having a magnitude obtained by multiplying this by the ground contact cross-sectional area A of the ball 88 acts on the ball 88. When a current is applied to the coil 80, a force F from the shaft 76 to the left in the figure acts on the ball 88. Since the regenerative ECU 20 causes the coil 80 to flow a current having a value corresponding to the determined valve opening value P ₀ , the magnitude of this force F can be expressed as P ₀ · A. Furthermore, FrW / C28
When there is a W / C pressure on the ball 88, P _{W / C} · A acts on the ball 88 in the right direction in the figure.

Therefore, in the pressure increasing side poppet valve 66, the force P _{M / C} · A in the right direction in the figure and the force F in the left direction in the figure F =
P ₀ · A + P _{W / C} · A is acting on the ball. Accordingly, in the state of (P _{M / C} −P _{W / C} ) <P ₀ , the ball 8
8 is grounded on the inner wall (valve seat) of the valve chamber 86 (except when the pressure reducing side poppet valve 68 described later is open), and the M / C 26
To FrW / C28 is cut off. Conversely, (P
_{In the state of M / C−} P _{W / C} )> P ₀ , the ball 88 separates from the inner wall of the valve chamber 86, the shaft 76 slides to the right in the figure, and the hydraulic pressure is applied to the W / C port 90 in the housing 74. Transmitted. This hydraulic pressure becomes P _{M / C} −P ₀ .

The pressure reducing poppet valve 68 is provided in the housing 72.
It is provided in. A ball 94 is housed in the valve chamber 92 of the pressure reducing poppet valve 68. M / C pressure P _{M / C} is F
When the pressure is higher than the W / C pressure of rW / C28, the oil passage is blocked by the ball 94 of the pressure reducing side poppet valve 68, and conversely, as in the case where the brake pedal 22 is returned, the FrW / C28
The oil passage is formed in a state in which the W / C pressure is higher than the M / C pressure P _{M / C.} As a result, the W / C pressure is reduced.

With this structure, the hydraulic valve 54 suitable for this embodiment can be obtained.

Second Embodiment FIG. 7 shows the configuration of a braking system according to the second embodiment of the present invention. This embodiment differs from the first embodiment in that a hydraulic valve 96 is provided instead of the P valve 56. The hydraulic valve 96 has the same structure as the hydraulic valve 54, and is controlled by the same procedure as the hydraulic valve 54. Further, the valve opening value of the hydraulic valve 54 and the valve opening value of the hydraulic valve 96 are set to the same value P ₀ .

Therefore, in this embodiment, when the M / C pressure P _{M / C} exceeds the valve opening value P ₀ , the hydraulic braking force by the RrW / C 30 starts to act. As a result, the total braking energy of the front and rear wheels changes as shown in FIG. 8 in accordance with the change in the M / C pressure P _{M / C.} Comparing this characteristic with the characteristic of the first embodiment shown in FIG. 4, the M / C pressure P
It can be seen that the recovery rate of braking energy until _{M / C} exceeds the valve opening value P ₀ is improved. That is, the braking energy consumed by the hydraulic braking on the rear wheel side in the region where the M / C pressure P _{M / C} does not exceed the valve opening value P ₀ in the first embodiment is regenerated in this embodiment. Therefore, the travelable distance per charge of the battery 16 becomes longer.
Further, in this embodiment, the braking force distribution between the front wheels and the rear wheels can always be kept good.

Configuration of Third Embodiment FIG. 9 shows the configuration of a braking system according to the third embodiment of the present invention. This embodiment has the same structure as the second embodiment, except that the valve opening value P _F set for the hydraulic valve 54 and the valve opening value P _R set for the hydraulic valve 96 are different. It is set. The valve opening value P _R is set to the same value as P ₀ in the first and second embodiments, and therefore M
When the / C pressure P _{M / C} exceeds the valve opening value P ₀ , first RrW / C
The braking force related to 30 starts to act. The valve opening value P _F is set so that the braking force distribution between the front wheels and the rear wheels becomes a preset distribution.

Operation of the Third Embodiment FIG. 10 shows the flow of the operation of the motor ECU 18 and the regenerative ECU 20 in this embodiment, particularly the operation relating to the braking control. The operation of this figure is different from the operation shown in FIG. 2 in that steps 124 and 126 are executed instead of steps 120 and 122. In step 124, the valve opening values P _F and P are set according to the regenerative ability.
_R is determined, and in step 126, the hydraulic valves 54 and 96 are controlled based on the determined valve opening values P _F and P _R.

Therefore, the total braking energy of the front wheels and the rear wheels in this embodiment changes with the characteristic shown in FIG. 11 according to the change of the M / C pressure P _{M / C.} That is, the first
Similarly to the second embodiment, the M / C pressure P _{M / C} is equal to the valve opening value P _R.
The braking energy recovery rate is good when it does not exceed. Second
When the M / C pressure P _{M / C} exceeds the valve opening value P _R and the hydraulic braking force begins to act, and the M / C pressure P _{M / C} exceeds the valve opening value P _F , the front and rear wheels are Since the braking force distribution during the braking is immediately controlled to a predetermined distribution, the behavior of the vehicle during braking becomes more stable.

Others The driving wheels may be front wheels or rear wheels. Further, in the first embodiment, the hydraulic valve 54 may be provided on the rear wheel side.

[0049]

As described above, according to the present invention,
The hydraulic pressure control signal is supplied to the valve of the hydraulic braking means that generates a differential pressure in accordance with the value of the supplied hydraulic pressure control signal, in response to the stop of the accelerator operation by the vehicle operator and prior to the start of the brake operation. Therefore, it is not necessary to use a configuration in which the load of the spring is adjusted by a solenoid as a valve that generates a differential pressure, and the delay due to the preset load of the spring can be eliminated.
Therefore, a stable braking ability and a good brake feeling can be obtained even when the regeneration ability is very small.
As a result, the travelable distance per charge of the vehicle also increases.

Further, according to the present invention, in a state where the hydraulic pressure control signal is not supplied, the hydraulic pressure generated in response to the brake operation of the vehicle operator acts as the hydraulic braking force as it is, so that the hydraulic braking means. Since it is configured, the reliable fail-safe can be realized by simply cutting off the supply of the hydraulic pressure control signal. At that time, since a solenoid valve for dealing with a fail is not necessary, the device configuration is simple, small, and lightweight.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a braking device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure in the first and second embodiments.

FIG. 3 is a diagram for explaining a regenerative braking start rotational speed.

FIG. 4 is a diagram showing a characteristic of M / C pressure versus braking energy in the first embodiment.

FIG. 5 is a cross-sectional view showing the structure of a hydraulic valve.

FIG. 6 is a diagram showing a balanced state in this hydraulic valve.

FIG. 7 is a block diagram showing a configuration of a braking device according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a characteristic of M / C pressure vs. braking energy in the second embodiment.

FIG. 9 is a block diagram showing a configuration of a braking device according to a third embodiment of the present invention.

FIG. 10 is a flowchart showing a control procedure in the third embodiment.

FIG. 11 is a diagram showing a characteristic of M / C pressure vs. braking energy in the third embodiment.

FIG. 12 is a block diagram showing a configuration of a braking device according to a conventional example.

FIG. 13 is a diagram showing a combination of regenerative braking energy and hydraulic braking energy.

FIG. 14 is a diagram showing a characteristic of M / C pressure vs. braking energy in a conventional example.

FIG. 15 is a diagram showing control of a valve opening value in a conventional example.

FIG. 16 is a diagram showing an influence of a preset load of a spring in a conventional example.

FIG. 17 is a diagram showing a problem of the conventional example.

[Explanation of symbols]

10 Motor 14 Inverter 16 Battery 18 Motor ECU 20 Regenerative ECU 22 Brake Pedal 26 Master Cylinder (M / C) 28 Front Wheel Cylinder (FrW / C) 30 Rear Wheel Cylinder (RrW / C) 36 Front Brake Rotor 38 Rear Brake Rotor 54 , 96 Hydraulic valve 56 P valve 60 Hydraulic sensor 64 Throttle sensor 66 Pressure increasing side poppet valve 68 Pressure reducing side poppet valve 70 Core 76 Shaft 78 Plunger 80 Coil 84 M / C port 86,92 Valve chamber 88,94 Ball 90 W / C port P _{M / C} master cylinder pressure (M / C pressure) P _{W / C} wheel cylinder pressure (W / C pressure) P ₀ , P _F , P _R valve opening value F force generated by suction of plunger A pressure increase side poppet valve Ground contact area of the ball

Claims (2)

[Claims] 1. A valve having a valve for generating a differential pressure according to the value of a supplied hydraulic control signal before and after the valve, the hydraulic pressure generated in response to a brake operation of a vehicle operator is reduced by the differential pressure. Hydraulic braking means that acts as a hydraulic braking force above, regenerative braking means that applies a regenerative braking force by regenerating electric power according to the value of the regeneration control signal by a motor for driving the vehicle, and a vehicle operator's brake Braking control means for generating a hydraulic pressure control signal and a regenerative control signal so that the braking force of the hydraulic braking force and the total braking force of the regenerative braking force have a predetermined relationship with the operation, and the electric power is generated by the hydraulic braking force and the regenerative braking force. In a braking device for braking an automobile, the braking control means preliminarily generates a hydraulic pressure control signal in response to a stop of an accelerator operation by a vehicle operator and prior to the start of a braking operation. 2. The braking device according to claim 1, wherein the hydraulic braking means does not generate a differential pressure by a valve when the hydraulic braking means is not supplied with the hydraulic control signal, and responds to a braking operation by a vehicle operator. A braking device characterized in that the generated hydraulic pressure acts as a hydraulic braking force.