JPH1044952A - Brake controller for electric motor vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely separate two systems comprising a hydrodynamic system and a hydrostatic system from each other and to provide an appropriate simulator function. SOLUTION: The first pressure chamber 74 and the second pressure chamber 75 on both sides of a piston 71 in a sub cylinder 70 are individually connected to a solenoid switching valve 61, which is arranged in parallel to a fluid pressure limiting switching device 20 arranged between a master cylinder 2 and wheel cylinders 51, 52, and to a solenoid switching valve 62 arranged between a regulator 3 and a reservoir 4. When regenerative braking based on an electric motor 11 is carried out, the solenoid switching valves 61, 62 are switched so that the first pressure chamber 74 is connected to the master cylinder 2 and the second pressure chamber 71 is connected to the low pressure reservoir 4. When regenerative braking based on the electric motor 11 is stopped, or when regenerative braking power is reduced, the solenoid switching valves 61, 62 are switched so that the first pressure chamber 74 is connected to the wheel cylinders 51, 52 and the second pressure chamber 75 is connected to the regulator 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device for an electric vehicle which uses both regenerative braking and hydraulic braking, and more particularly to a static hydraulic output unit and a dynamic hydraulic output unit. The present invention relates to a braking control device for an electric vehicle configured to supply an output hydraulic pressure of a dynamic hydraulic pressure output unit to a wheel cylinder to apply a braking force to a wheel cylinder when adding and switching braking.

[0002]

2. Description of the Related Art In recent years, in an electric vehicle using an electric motor as a drive source, regenerative braking is performed in which the electric motor functions as a generator and charges a battery to recover energy and increase energy when the electric motor is driven. Is being done. Since there is a limit to the application of the braking force by the regenerative braking, it is necessary to supplement with the hydraulic braking, and the hydraulic braking and the regenerative braking are used together. For example, JP-A-5-1764
Japanese Patent Application Laid-Open No. 06-2006 discloses an aim of realizing a precise brake control adapted to the difference between the maximum regenerative braking force at high speed and at low speed, and to provide a plurality of shut-off means from the hydraulic pressure output means to the hydraulic pressure from the hydraulic cylinder to the wheel cylinder of the driving wheel. It is provided in cascade on the transmission path, shuts off the hydraulic pressure generated by the hydraulic pressure output means to a predetermined value, and selectively disconnects a plurality of shutoff means according to the rotation speed of the traveling motor by the communication switching means, thereby shutting off a plurality of shutoffs Braking control devices have been proposed in which the communication between the means is switched. Specifically, when the differential pressure ΔP exceeds the opening value of only the pressure reducing valve 30 at a high speed, the differential pressure ΔP increases at a low speed.
When the sum of the valve opening values exceeds 2, the hydraulic braking corresponding to the excess hydraulic pressure is applied. Stroke simulators 42 and 44 are provided as means for creating a consumed liquid amount and improving the brake feeling when the hydraulic pressure is shut off. These are described as being consumed in a manner similar to the brake master cylinder 26 when the hydraulic pressure is shut off by the pressure reducing valve 30 or 32.

Japanese Patent Application Laid-Open No. 7-336806 discloses an on / off switch between a master cylinder and a wheel cylinder.
In contrast to the prior art in which an off valve is interposed and closed during regenerative braking, the same publication discloses that a brake pedal is used when the on / off valve is switched from a closed state to an open state in order to release the regeneration priority mode. The present invention discloses a brake device that temporarily reduces the pressure of a hydraulic booster into a wheel cylinder and rapidly increases the pressure of the wheel cylinder, with the object of suppressing the sinking of the pedal and the fluctuation of the pedal effort. Have been. That is, when switching from regenerative braking to hydraulic braking by the master cylinder, the master cylinder hydraulic pressure temporarily decreases until the wheel cylinder hydraulic pressure approaches the master cylinder hydraulic pressure, and the stroke of the brake pedal changes rapidly. In this publication, the differential pressure of the relief valve VR2 is reduced so that a large differential pressure is not generated between the master cylinder hydraulic pressure and the wheel cylinder hydraulic pressure. When releasing, the solenoid valve V1 is first closed, then the solenoid valve V4 is opened, and the output hydraulic pressure of the hydraulic booster HB is temporarily introduced into the wheel cylinder.

[0004]

However, in the braking control device described in Japanese Patent Application Laid-Open No. Hei 5-176406, since the stroke simulators 42 and 44 are provided, the size of the device becomes large, and there is a demand for miniaturization. Would be contrary to

In the braking device described in Japanese Patent Application Laid-Open No. 7-336806, a relief valve VR2, a solenoid valve V5, and a check valve VC2 for adding and switching hydraulic braking to regenerative braking are provided (master cylinder). Solenoid valve V4 for the static hydraulic system (between
Is connected to the hydraulic booster HB of the dynamic hydraulic system. The brake fluid is supplied from the hydraulic booster HB to the static hydraulic system when the hydraulic braking is added to or switched to the regenerative braking, and the two systems of the brake hydraulic system are connected via the electromagnetic valve V4. If the dynamic hydraulic system is in a state of failure while the solenoid valve V4 is open, the brake fluid of the static hydraulic system will flow out. Therefore, it is desired to appropriately separate the two brake hydraulic systems.

Therefore, the present invention provides a brake control device for an electric vehicle including a static hydraulic pressure output unit and a dynamic hydraulic pressure output unit. An object of the present invention is to provide a braking control device that is separated and has an appropriate simulator function.

[0007]

In order to achieve the above object, an electric vehicle braking control apparatus according to the present invention comprises: an electric motor connected to wheels of a vehicle; and a driving force applied to the wheels by rotating the electric motor. Motor control means for applying a braking force to the wheels by regenerative braking of the electric motor, and a static control for increasing the brake fluid in the reservoir in response to the operation of the brake operating member and outputting a static fluid pressure. A hydraulic pressure output means, an auxiliary hydraulic pressure source that boosts the brake fluid in the reservoir independently of the operation of the brake operating member and outputs power hydraulic pressure, and outputs the power hydraulic pressure of the auxiliary hydraulic pressure source to the brake. Dynamic hydraulic pressure output means for adjusting the pressure in response to the operation of the operating member and outputting a dynamic hydraulic pressure; a wheel cylinder mounted on the wheel to apply a braking force; and the static hydraulic pressure output means for the wheel cylinder Or A hydraulic pressure control means for supplying an output hydraulic pressure of the dynamic hydraulic pressure output means and applying a braking force to the wheels; and a main hydraulic passage connecting the static hydraulic pressure output means and the wheel cylinder. When applying a braking force to the wheel by the motor control means, the hydraulic pressure supplied from the static hydraulic pressure output means to the wheel cylinder is made lower than the output hydraulic pressure of the static hydraulic pressure output means, Hydraulic pressure limit switching means for matching the hydraulic pressure supplied from the static hydraulic pressure output means to the wheel cylinder to the output hydraulic pressure of the static hydraulic pressure output means when the braking force is not applied to the wheel by the means. In a brake control device for an electric vehicle, a piston is slidably housed in a cylinder to define a first pressure chamber and a second pressure chamber in the cylinder, and the piston is moved forward by an urging means. A sub-cylinder that urges the first pressure chamber in a direction to reduce the pressure, a first position of the sub-cylinder that communicates the first pressure chamber with the static hydraulic pressure output unit, and the first pressure chamber. A first switching valve for selectively switching a second position communicating with the wheel cylinder, a first position communicating the second pressure chamber of the sub-cylinder with the reservoir, and the second pressure chamber. And a second switching valve for selectively switching at least two of the second positions communicating with the dynamic hydraulic pressure output means.

Incidentally, as the second switching valve, a 3-port 2-position electromagnetic switching valve can be used. Further, as the dynamic hydraulic pressure output means, the output hydraulic pressure of the auxiliary hydraulic pressure source is input, and the output hydraulic pressure of the master cylinder as the static hydraulic pressure output means is used as the pilot pressure, and the regulator hydraulic pressure is proportional to the pilot hydraulic pressure. A regulator that regulates the pressure and outputs the pressure, or a hydraulic booster that regulates the boost hydraulic pressure (regulator hydraulic pressure) and drives the master cylinder in a similar manner can be used.

During the regenerative braking, the first switching valve and the second switching valve are each set to the first position, so that the sub-cylinder functions as a simulator in accordance with the operation of the brake operating member. I do. When adding and switching the hydraulic braking with respect to the regenerative braking, the static hydraulic pressure is set by setting the first switching valve to the second position and setting the second switching valve to the second position. The differential pressure between the output hydraulic pressure of the output means and the hydraulic pressure in the wheel cylinder is quickly eliminated, and a smooth braking operation can be performed.

As set forth in claim 2, the second switching valve has a first position in which the second pressure chamber of the sub-cylinder communicates with the reservoir, and a second position in which the second pressure chamber is connected to the dynamic chamber. It may be a three-position switching valve for selectively switching the three positions of a second position communicating with the hydraulic pressure output means and a third position for cutting off the communication with the outside of the second pressure chamber. For example, a 3-port 3-position electromagnetic switching valve can be used. It should be noted that a configuration having the same function as the three-port three-position electromagnetic switching valve may be provided by using a pair of two-port two-position electromagnetic switching valves.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a braking control device for an electric vehicle according to an embodiment of the present invention, which includes an electric motor 11 for performing regenerative braking and a hydraulic pressure control device for performing hydraulic braking. It has a master cylinder 2 as a means and a regulator 3 as a dynamic hydraulic pressure output means, and these are driven according to the operation of the brake pedal 5. In FIG. 1, wheels FR indicate front right wheels as viewed from the driver's seat, wheels FL indicate front left wheels, wheels RR indicate rear right wheels, and wheels RL indicate rear left wheels.
Wheel cylinders 51 to 54 are mounted on L, RR, and RL. In the present embodiment, a so-called front-rear piping type brake hydraulic system divided into a front-wheel hydraulic control system and a rear-wheel hydraulic control system is configured.

The electric vehicle according to the present embodiment has a front wheel F
R and FL are drive wheels, and rear wheels RR and RL are related to so-called front wheel drive of driven wheels. The wheels FR and FL are connected to a drive electric motor 11 via a transmission 12. The drive is controlled by the electronic control unit 10. The electronic control unit 10 includes a microcomputer 10a for motor control as motor control means for driving and controlling the electric motor 11 and a microcomputer 10b for hydraulic pressure control as hydraulic pressure control means. An example of the construction is described in, for example, the above-mentioned Japanese Patent Application Laid-Open No. 7-3368.
The description is omitted because it is the same as that described in Japanese Patent Publication No. 06-2006.

The electric motor 11 generates a rotating magnetic field by applying AC power to three-phase windings of the stator,
It is composed of an induction motor that rotationally drives a rotor having a permanent magnet. Therefore, a motor drive circuit (not shown) controlled by the microcomputer is provided with an inverter. According to the electric motor 11, when the wheels FR and FL are rotating, the magnetic field is generated by the stator in a direction to stop the rotation, so that the braking force is applied to the rotor and the stator is The electromotive force generated in the winding can be collected in a battery (not shown). Thereby, regenerative braking is performed.

In FIG. 1, an auxiliary hydraulic pressure source 40 is connected to the regulator 3, and these are connected to the master cylinder 2.
Together with the low-pressure reservoir 4. Auxiliary hydraulic pressure source 4
0 has a hydraulic pump 41 and an accumulator 44. The hydraulic pump 41 is driven by an electric motor 42 to increase and output the brake fluid in the low-pressure reservoir 4, and this brake fluid is supplied to an accumulator 44 through a check valve 43.
And stored. The electric motor 42 is driven in response to the hydraulic pressure in the accumulator 44 falling below a predetermined lower limit, and stops in response to the hydraulic pressure in the accumulator 44 exceeding the predetermined upper limit. Thus, a so-called power hydraulic pressure is supplied from the accumulator 44 to the regulator 3 as appropriate. The regulator 3 includes an auxiliary hydraulic pressure source 40
And the output hydraulic pressure of the master cylinder 2 is used as a pilot pressure to regulate the regulator hydraulic pressure in proportion to the pilot hydraulic pressure (a value substantially equal to the master cylinder hydraulic pressure). The basic configuration is well known. The description is omitted. A part of the regulator hydraulic pressure is used for boosting the master cylinder 2.

The main hydraulic pressure passage 8 on the front wheel side connecting the master cylinder 2 and each of the wheel cylinders 51, 52 in front of the vehicle.
Is provided with a hydraulic pressure limit switching device 20 as a hydraulic pressure limit switching means for adding and switching hydraulic braking to regenerative braking. The main hydraulic pressure path 9 on the rear wheel side, which connects the regulator 3 and each of the wheel cylinders 53 and 54 on the rear side of the vehicle,
Although the hydraulic pressure limit switching device 30 is interposed, the configuration is slightly different from the hydraulic pressure limit switching device 20 as described later.

As shown in FIG. 1, the hydraulic pressure limit switching device 20 includes a relief valve 21, an electromagnetic on-off valve 22, and a proportioning valve 23 connected in parallel. The relief valve 21 restricts the communication of the main hydraulic pressure line 8 until the output hydraulic pressure of the master cylinder 2 reaches a predetermined hydraulic pressure, and connects the main hydraulic pressure line 8 when the output hydraulic pressure exceeds a predetermined hydraulic pressure. It is. The electromagnetic opening / closing valve 22 is an electromagnetic valve that is driven and controlled by the electronic control device 10 and opens and closes the main hydraulic pressure path 8 in accordance with a result of the determination made by the electronic control device 10 as to whether regenerative braking should be performed. The proportioning valve 23 is a hydraulic pressure control valve that controls the output hydraulic pressure of the master cylinder 2 according to the operation of the brake pedal 5 in a predetermined relationship and supplies the hydraulic pressure to the wheel cylinders 51 and 52. Although it has substantially the same configuration as the proportioning valve used for distribution control, the hydraulic pressure at the turning point is kept low as described later. It should be noted that pressure sensors 24 and 25 are disposed upstream and downstream of the relief valve 21 (electromagnetic on-off valve 22), respectively.

On the other hand, the hydraulic pressure limit switching device 30 on the rear wheel side
The relief valve 31, the electromagnetic on-off valve 32, and the check valve 33 are connected in parallel. The relief valve 31 is an output hydraulic pressure of the regulator 3 (substantially equal to the master cylinder hydraulic pressure).
The communication of the main hydraulic passage 9 is restricted until the pressure reaches a predetermined hydraulic pressure, and the main hydraulic passage 9 is connected when the hydraulic pressure becomes equal to or higher than a predetermined hydraulic pressure. The electromagnetic on-off valve 32 is driven and controlled by the electronic control unit 10 in the same manner as the electromagnetic on-off valve 22, and opens and closes the main hydraulic pressure passage 9 according to the determination result of the electronic control unit 10 on whether or not to perform regenerative braking. Solenoid valve. As shown in FIG. 1, the check valve 33 allows the flow of the brake fluid in the direction of the regulator 3, and the wheel cylinders 53, 5
It blocks the flow in four directions.

The main hydraulic lines 8 and 9 are connected to hydraulic lines 8a and 9 respectively.
a branches off, and a sub-cylinder 70 is connected to them. The sub-cylinder 70 has a piston 7 in a cylinder 71.
2 are slidably accommodated, and a first pressure chamber 74 and a second pressure chamber 75 are formed on both sides of the cylinder 71 via the piston 72. A compression spring 73 is housed in the second pressure chamber 75, and when no hydraulic pressure is applied to the first and second pressure chambers 74 and 75, the second pressure chamber 75 has a maximum capacity (accordingly, The compression spring 73 urges the piston 72 rightward in FIG. 1 so that the first pressure chamber 74 has the minimum capacity. And the first
The pressure chamber 74 is connected to the electromagnetic switching valve 61 via the hydraulic path 8b, and the second pressure chamber 75 is connected to the electromagnetic switching valve 62 via the hydraulic path 9b.

The electromagnetic switching valve 61 is a three-port two-position electromagnetic switching valve. At a first position when not operated, as shown in FIG. 1, a first pressure chamber 74 is provided via hydraulic passages 8a and 8b. Main hydraulic passage 8 between master cylinder 2 and hydraulic restriction switching device 20
In the second position during operation, the first pressure chamber 74 communicates with the main hydraulic pressure passage 8 between the hydraulic pressure limit switching device 20 and the wheel cylinders 51, 52 via the hydraulic pressure passages 8b, 8c. I do.
The electromagnetic switching valve 62 is also a 3 port 2 position electromagnetic switching valve,
In the first position when not in operation, as shown in FIG. 1, the second pressure chamber 75 communicates with the low-pressure reservoir 4 through the hydraulic paths 9a and 9b, and in the second position when in operation, the second pressure chamber 75 is in the second position. 75 communicates with the main hydraulic pressure line 9 between the regulator 3 and the hydraulic pressure limit switching device 30 via the hydraulic pressure lines 9b and 9c.

In the sub-cylinder 70, master cylinder hydraulic pressure or wheel cylinder hydraulic pressure is applied to the first pressure chamber 74, and regulator hydraulic pressure is applied to the second pressure chamber 75, or The pressure chamber is brought to the atmospheric pressure in communication with the pressure chamber 4, and both pressure chambers are hydraulically separated by a piston 72. When the hydraulic pressure is not applied to the first and second pressure chambers 74 and 75, the piston 72 is at a position where the capacity of the first pressure chamber 74 is minimized as shown in FIG. Therefore, the electromagnetic switching valves 61 and 62
Is in the first position, the first pressure chamber 74 communicates with the master cylinder 2 as shown in FIG.
5 is connected to the reservoir 4 and is set to the atmospheric pressure. When the master cylinder hydraulic pressure is output in response to the operation of the brake pedal 5, the master cylinder hydraulic pressure is reduced to the relief valve 21.
Until the valve opening pressure is reached, the piston 72 is driven against the urging force of the compression spring 73, so that the sub cylinder 70 functions as a simulator.

When the piston 72 of the sub-cylinder is driven against the urging force of the compression spring 73, the electromagnetic switching valves 61 and 62 are in the second position, and the second pressure is set via the electromagnetic switching valve 62. When the regulator hydraulic pressure is applied to the chamber 75, the piston 72 is driven in a direction to reduce the first pressure chamber 74, so that the wheel cylinders 51, 8 c via the hydraulic pressure paths 8 b and 8 c and the main hydraulic pressure path 8. At 52, the brake fluid in the first pressure chamber 74 is discharged and the pressure is increased. At this time, the amount of the brake fluid discharged to the wheel cylinders 51 and 52 is limited by the maximum capacity of the first pressure chamber 74.
The brake fluid is not excessively supplied to the wheel cylinders 51 and 52.

The relief valve 21, the solenoid on-off valve 22 and the proportioning valve 23 constituting the above-mentioned hydraulic pressure limit switching device 20 have the characteristics shown in FIG. That is, the characteristic of the proportioning valve 23 is that the master cylinder hydraulic pressure increases in response to the operation of the brake pedal 5 at the beginning of the braking operation, and the wheel cylinder hydraulic pressure increases in proportion to the master cylinder hydraulic pressure. When the pressure reaches a predetermined pressure Pa, the pressure becomes substantially constant, and even if the master cylinder hydraulic pressure increases, the wheel cylinder hydraulic pressure only slightly increases. The predetermined pressure Pa is such that the wheel cylinder 51 and the like are filled with the brake fluid, and the brake pad (not shown) is rotated by the rotor (not shown).
Is set low enough to abut against Thus, the proportioning valve 23 has a function of filling the brake fluid into the wheel cylinder at the beginning of the brake operation, a function of shutting off the fluid pressure until the relief valve 21 is activated, and a function of braking the master cylinder 2 from the wheel cylinder 51 and the like. It has a function to return the liquid.

The characteristic of the relief valve 21 is that it is in a closed state until the master cylinder hydraulic pressure reaches a predetermined pressure Pb, opens when the master cylinder hydraulic pressure exceeds the predetermined pressure Pb, and thereafter is proportional to an increase in the master cylinder hydraulic pressure. The wheel cylinder hydraulic pressure increases. When the electromagnetic on-off valve 22 is in the open position,
As shown by the broken line in FIG. 4, the wheel cylinder hydraulic pressure coincides with the master cylinder hydraulic pressure. In other words, in FIG. 4, a dotted region surrounded by a dashed line indicating the characteristics of the electromagnetic on-off valve 22 and a solid line indicating the characteristics of the relief valve 21 and the proportioning valve 23 is a decompression region, This is a range in which regenerative braking is performed instead of pressure braking.

As shown in FIG. 1, the brake pedal 5 is provided with a brake switch 6 which is turned on when the brake pedal is depressed, and is connected to the electronic control unit 10 like the pressure sensors 24 and 25. . Also, the shift position of the transmission 12 is detected and the electronic control unit 10
Is supplied with a detection signal. Further, wheels FR, FL, R
Wheel speed sensors (not shown) are provided at R and RL.
These are connected to the electronic control unit 10, and the rotation speed of each wheel, that is, a pulse signal having a pulse number proportional to the wheel speed is supplied to the electronic control unit 10.

In the braking control device configured as described above, the hydraulic pump 41 is driven by the electric motor 42, and the power hydraulic pressure is accumulated in the accumulator 44. When the brake pedal 5 is depressed when each solenoid valve is in the state shown in FIG. 1, the master cylinder 2 outputs the master cylinder hydraulic pressure and the regulator 3 outputs the regulator hydraulic pressure. And the electromagnetic switching valve 6
1 and 62 and the solenoid on-off valves 22 and 32
And the braking control is performed as described below.

For example, when the brake pedal 5 is operated in a state where the electronic control unit 10 determines that regenerative braking should be performed while the vehicle is running at high speed (the shift position is the drive position), regenerative braking starts. . During this time, the electromagnetic switching valves 61 and 62 are in the off-state first position shown in FIG. 1 and the electromagnetic on-off valves 22 and 32 are in the on-state closed position. Therefore, normal hydraulic braking that directly responds to the brake pedal 5 is not performed, and only the initial hydraulic fluid is filled in the brake hydraulic system in response to the operation of the brake pedal 5. From the start of the operation of the brake pedal 5 to the predetermined pressure Pa, the wheel cylinder hydraulic pressure increases in proportion to the increase of the master cylinder hydraulic pressure, but when the master cylinder hydraulic pressure reaches the predetermined pressure Pa, FIG. Based on the characteristics of the proportioning valve 23 shown, the pressure Pa is used as a turning point to control the increase rate of the wheel cylinder pressure to be smaller than the increase rate of the master cylinder pressure.

Thus, the initial stroke of the brake pedal 5 is secured, but the value of the wheel cylinder hydraulic pressure is kept low. During this time, the sub cylinder 70 functions as a simulator. That is, the brake fluid of the master cylinder 2 is introduced into the first pressure chamber 74 via the electromagnetic switching valve 61, and the piston 72 is driven against the urging force of the compression spring 73. The same brake operation feeling as in pressure braking is provided. Further, when the output hydraulic pressure of the master cylinder 2 rises and exceeds the valve opening pressure Pb of the relief valve 21 having the characteristics shown in FIG. 4, the master cylinder hydraulic pressure is supplied to the wheel cylinders 51 and 52.
Until the master cylinder hydraulic pressure (regulator hydraulic pressure) exceeds the valve opening pressure Pb of the relief valve 21 (relief valve 31), the braking operation is performed only by the regenerative braking.
When the pressure exceeds the valve opening pressure Pb of the (relief valve 31), the braking operation is performed by regenerative braking and hydraulic braking.

As described above, the switching control of the electromagnetic switching valves 61 and 62, the opening / closing control of the electromagnetic switching valves 22 and 32, and the operation of the relief valves 21 and 31 and the proportioning valve 23 change the braking operation from the regenerative braking only. Switching to braking operation by braking and hydraulic braking is also performed smoothly.

When the electronic braking device 10 determines that the regenerative braking should be stopped when the vehicle is in an extremely low speed region near the end of the braking operation, the regenerative braking is stopped and the braking operation is performed only by the hydraulic braking. That is, on the front wheel side, the master cylinder hydraulic pressure is supplied to the wheel cylinders 51, 52 via the electromagnetic on-off valve 22, and on the rear wheel side, the regulator hydraulic pressure is supplied to the wheel cylinders 53, 54 via the electromagnetic on-off valve 32. Will be. In this case, simply switching the solenoid on-off valves 22 and 23 from the closed position to the open position causes the front wheel side to change from a state where the difference between the master cylinder hydraulic pressure and the wheel cylinder hydraulic pressure is large.
Since the difference is reduced at a stroke only by the master cylinder hydraulic pressure, a so-called pedal shock occurs in the brake pedal 5. On the other hand, in the present embodiment, the electromagnetic switching valve 6
With 1 being in the second position, the electromagnetic switching valve 62 is switched to the second position.

That is, the electromagnetic switching valves 61 and 62 are
When the position is switched to the position, the regulator hydraulic pressure is introduced from the regulator 3 into the second pressure chamber 75 of the sub cylinder 70 and is supplied to the wheel cylinders 51 and 52. The difference between the hydraulic pressure and the wheel cylinder hydraulic pressure is reduced at once, but the braking force applied at this time is
Since the pressure is due to the brake fluid stored in the first pressure chamber 74, the fluctuation of the pedaling force of the brake pedal 5 is greatly reduced and stabilized, and no pedal shock occurs. At the time of hydraulic braking at this time, the sub cylinder 7
0, the regulator hydraulic pressure and the wheel cylinder hydraulic pressure are hydraulically separated.
The amount of brake fluid discharged to the first and second pressure chambers 7 and 52
Since the maximum capacity of 4 is the limit, no excessive brake fluid is supplied. Note that the electromagnetic switching valve 62 may be appropriately turned on / off until the difference between the master cylinder hydraulic pressure and the wheel cylinder hydraulic pressure is eliminated.

FIG. 2 shows a brake control device for an electric vehicle according to another embodiment of the present invention, in which a three-port three-position electromagnetic switching valve 63 is used as a second switching valve of the present invention. is there. This corresponds to the second pressure chamber 75 of the sub cylinder 70.
Are connected to the low-pressure reservoir 4, a second position that connects the second pressure chamber 75 to the regulator 3, and a third position that cuts off communication with the outside of the second pressure chamber 75. An electromagnetic switching valve for selectively switching. Thus, in addition to the control in the above-described embodiment, the electromagnetic pressure in the second pressure chamber 75 can be maintained by setting the electromagnetic switching valve 63 to the third position.

Accordingly, the regenerative braking force is set to, for example, the upper limit of 50.
% When it is necessary to reduce the
By moving the piston 72 to the intermediate position of the full stroke, the hydraulic braking force can be increased to compensate for the braking force.
Thus, according to the embodiment of FIG. 2, finer control is possible as compared to control such as execution or suspension of regenerative braking.

FIG. 3 relates to still another embodiment of the present invention. As a second switching valve of the present invention, a pair of 2-port 2
The three-port three-position electromagnetic switching valve 63 is configured to have the same function as the three-port three-position electromagnetic switching valve 63 by using the electromagnetic switching valves 64 and 65 at the positions. That is, a normally-closed electromagnetic on-off valve 64 is disposed between the hydraulic pressure paths 9a and 9b, and the low-pressure reservoir 4 is connected to the hydraulic pressure path 9b via the hydraulic pressure path 9c. An on-off valve 65 is provided. By setting the electromagnetic on-off valves 64 and 65 to the closed position, the hydraulic pressure in the second pressure chamber 75 can be maintained, and fine control can be performed similarly to the embodiment of FIG. .

[0034]

The present invention has the following effects because it is configured as described above. That is, in the brake control device for the electric vehicle according to the first aspect, the sub-cylinder has a function as a simulator, and addition and switching of the hydraulic braking with respect to the regenerative braking are performed by the first and second switching valves. Since the operation can be smoothly performed according to the output hydraulic pressure of the dynamic hydraulic pressure output means via the sub-cylinder, stable braking operation can be ensured. In addition, since the dynamic hydraulic system and the static hydraulic system are reliably separated by the sub-cylinder, even when the dynamic hydraulic system fails, the brake fluid of the static hydraulic system does not flow out. The braking operation can be performed at the same time.

Further, in the case of the structure described in claim 2, since it is possible to set the hydraulic pressure in the second pressure chamber of the sub-cylinder to be maintained, it is possible to perform fine braking control. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a braking control device for an electric vehicle according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a braking control device according to another embodiment of the present invention.

FIG. 3 is a configuration diagram of a braking control device according to still another embodiment of the present invention.

FIG. 4 shows a relief valve according to an embodiment of the present invention;
4 is a graph showing a relationship between a master cylinder hydraulic pressure and a wheel cylinder hydraulic pressure by a proportioning valve and an electromagnetic on-off valve.

[Explanation of symbols]

 2 Master cylinder (static hydraulic pressure output means) 3 Regulator (dynamic hydraulic pressure output means) 4 Low pressure reservoir 5 Brake pedal (brake operating member) 8 Main hydraulic pressure path 10 Electronic control unit 11 Electric motor 20, 30 Hydraulic pressure limit Switching device (fluid pressure limit switching means) 21, 31 Relief valve 22, 32 Electromagnetic on-off valve 23 Proportioning valve 24, 25 Pressure sensor 40 Auxiliary hydraulic pressure source 41 Hydraulic pump 51, 52, 53, 54 Wheel cylinder 61, 62 , 63, 64, 65 Solenoid switching valve FR, FL, RR, RL Wheel

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Masaki Ando 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Inventor Shingo Urababa 1-Toyota-cho, Toyota-shi, Aichi Prefecture Toyota (72) Inventor Harumi Ohori 1st Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (2)

[Claims] An electric motor connected to wheels of a vehicle, and a motor control means for rotating the electric motor to apply a driving force to the wheels and applying a braking force to the wheels by regenerative braking of the electric motor. Static fluid pressure output means for increasing the brake fluid in the reservoir in response to operation of the brake operating member and outputting static fluid pressure; and increasing the brake fluid in the reservoir independently of the operation of the brake operating member. An auxiliary hydraulic pressure source that outputs a power hydraulic pressure, and a dynamic hydraulic pressure output unit that outputs a dynamic hydraulic pressure by adjusting the output power hydraulic pressure of the auxiliary hydraulic pressure source in accordance with the operation of the brake operating member. A wheel cylinder mounted on the wheel to apply a braking force, and supplying an output hydraulic pressure of the static hydraulic pressure output means or the dynamic hydraulic pressure output means to the wheel cylinder to apply a braking force to the wheel. Hydraulic control Control means, interposed in a main hydraulic pressure path connecting the static hydraulic pressure output means and the wheel cylinder, and when applying a braking force to the wheels by the motor control means, the static hydraulic pressure output means When the hydraulic pressure supplied to the wheel cylinder is lower than the output hydraulic pressure of the static hydraulic pressure output means, and when the braking force is not applied to the wheels by the motor control means, the hydraulic pressure is supplied from the static hydraulic pressure output means to the wheel cylinder. And a hydraulic pressure limit switching means for matching the hydraulic pressure to be output with the output hydraulic pressure of the static hydraulic pressure output means. A first pressure chamber and a second pressure chamber, and a sub-cylinder for urging the piston in a direction to reduce the first pressure chamber by a urging means; A first position in which the first pressure chamber communicates with the static hydraulic pressure output means and a second position in which the first pressure chamber communicates with the wheel cylinder; A first position for communicating said second pressure chamber with said reservoir;
And a second mechanism for selectively switching at least two of the second positions communicating the second pressure chamber with the dynamic hydraulic pressure output means.
And a switching valve for the electric vehicle. 2. The second switching valve has a first position in which the second pressure chamber of the sub-cylinder communicates with the reservoir, and a second position in which the second pressure chamber communicates with the dynamic hydraulic pressure output means. 2. A braking device for an electric vehicle according to claim 1, wherein the switching device is a three-position switching valve that selectively switches between three positions, that is, a second position and a third position for interrupting communication with the outside of the second pressure chamber. Control device.