JP2001130396A - Vehicle having high detection accuracy of traveling speed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a traveling speed of vehicle without wasting a brake force. SOLUTION: Respective electromotive brakes of four wheels are operated by electric motors to inhibit a rotation of the wheels and the four electric motors are controlled by a motor control device respectively. If the electric brakes become inoperative brakes by a cause at the motor control device side or the electric brake side, a traveling speed of vehicle is taken based on a rotation speed of a wheel having the inoperative brakes (defect wheel). At the time of non-operation of the brakes, if a non-driving wheel exists at the defect wheel at the time of operation, a traveling speed of the vehicle is taken based on a rotation speed of the non-driving wheel. Even if the defect wheel at the time of operation of the brake is a driving wheel, a traveling speed of the vehicle is taken based on a rotation speed of the driving wheel if an acceleration pedal is not stepped-in. No slip exists at the defect wheel which is not driven and braked and a traveling speed of the vehicle is accurately taken without wasting the braking force. An anti-lock control, etc., can be accurately carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to detection of a traveling speed of a vehicle, and more particularly to improvement of detection accuracy.

[0002]

2. Description of the Related Art The traveling speed of a vehicle is, for example, as disclosed in
As described in Japanese Patent Application No. 55905, it is required when performing antilock control. In the vehicle described in this publication, during the period from the start of braking to the start of antilock control, the speed obtained by lowering the running speed at the start of braking at a constant rate is used as the running speed, and the antilock control starts. If so, the braking is released for one of the left and right rear wheels, and the running speed of the vehicle is acquired based on the rotation speed of the rear wheel whose rotation is not suppressed, and the antilock control is performed. If the rotation is not suppressed, the wheels do not slip, and the traveling speed of the vehicle can be accurately acquired.

[0003]

SUMMARY OF THE INVENTION However, in the vehicle described in the above publication,
Since the traveling speed is obtained by not operating the brake capable of suppressing the rotation of the wheel, the braking force to be obtained cannot be obtained correspondingly, which is wasteful.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a vehicle capable of accurately detecting a traveling speed without causing a waste of braking force. Thus, the following vehicles can be obtained. As in the case of the claims, each aspect is divided into sections, each section is numbered, and if necessary, the other sections are cited in a form in which the numbers are cited. This is for the purpose of facilitating the understanding of the present invention and should not be construed as limiting the technical features and combinations thereof described in the present specification to those described in the following sections. . Further, when a plurality of items are described in one section, the plurality of items need not always be adopted together. It is also possible to select and adopt only some of the items. (1) A plurality of brakes provided on each of a plurality of wheels, and a brake control device that operates at least one of the plurality of brakes based on at least one of a brake operation by a driver and a traveling state of the vehicle. An inoperative brake detecting device that detects one of the plurality of brakes that should be operated but does not operate, and a rotational speed of a wheel corresponding to the brake detected by the inoperative brake detecting device. And a traveling speed acquisition device that acquires the traveling speed of the vehicle by using the vehicle. When a plurality of inoperative brakes are detected, the traveling speed acquisition device may acquire the traveling speed from the rotational speeds of all the wheels corresponding to the detected inoperative brakes. It may be obtained based on the rotation speed of the wheel. The inoperative brake detection device may detect the inoperative brake at any time.For example, the inoperative brake detection device may detect the inoperative brake when actually operating the brake. It may be detected. It may be considered that the information of the inoperative brake detected in advance is used when the brake is actually operated, as the detection of the inoperative brake. Among the plurality of brakes, the cause of the inoperative brake that should be activated but not activated may be on the brake side or on the brake control device side. Non-operating brakes include a brake that does not operate because the brake control device cannot operate the brake even if the brake itself is normal, and a brake control device that is normal and can operate the brake. It includes a brake that does not operate because it is abnormal, and a brake that does not operate because both are abnormal. In any case, no slip occurs on the wheels corresponding to the brakes that should be actuated but not actuated, and the running speed of the vehicle can be accurately acquired based on the rotation speed of the wheels. In this aspect, in order to acquire the traveling speed based on the rotation speed of the wheel corresponding to the brake which should be activated but does not operate but cannot be obtained to obtain the braking force. In addition, the traveling speed can be obtained without wasting the braking force as in the related art. As a result, for example, control using the running speed of the vehicle, such as anti-lock control, can be performed with high accuracy. In addition to the control of the brake, the accuracy and reliability of the operation and functions of the device using the running speed of the vehicle can be improved. Properties and the like can be improved. In particular, when the running speed of the vehicle is used for controlling the brake system, the brake operation force should be increased or the brake operation force should be automatically increased if an inoperative brake that does not operate occurs despite the fact that it should operate. It is necessary to increase the operating force of the brake to be applied, but in such a situation, it is very beneficial to obtain an accurate traveling speed and thereby improve the control accuracy of the brake system. It is. (2) The inoperative brake detection device includes an operation command disabled brake detection unit that detects a brake that cannot be operated due to a cause on the brake control device side.
The vehicle according to (1) (Claim 2). If the cause of the occurrence of the inoperative brake is on the brake side, the inoperative brake is an inoperable brake, and if the cause is on the brake control device side, the inoperative brake is an operation command inoperative brake. The brake control device is configured in various modes as described in the embodiments of the invention and in the paragraphs (5) to (7) .For example, a part of a plurality of brakes is controlled by the brake control device. If at least a part of the plurality of brakes becomes an operation-impossible brake due to failure of at least a part of the brake control device, or if all of the plurality of brakes are individually controlled by the brake control device, the brake control device As a result, a part of the plurality of brakes becomes an operation command disabled brake. The brake does not operate even if the brake itself does not have the cause of the inoperative, and the traveling speed of the vehicle is accurately acquired based on the rotation speed of the wheel having the inoperative brake. For example, anti-lock control for preventing the wheel slip (slip amount, slip rate) from becoming excessive because the braking torque applied to each wheel during braking of the vehicle is excessive in relation to the friction coefficient of the road surface. If the brakes corresponding to some of the wheels cannot be actuated for some reason, such as a failure of the part that controls them, the traveling speed of the vehicle is determined based on the rotation of the wheels corresponding to the brakes. If it is detected, the detection accuracy of the traveling speed is improved, and the control accuracy of the antilock control is also improved. Also, it is often necessary or desirable to detect the presence or absence of an inoperable cause, which is a cause of non-operation on the brake side, by actually operating the brake.
The presence or absence of an operation command impossibility cause, which is a cause of non-operation on the brake control device side, can often be detected without actually operating the brake, and in that respect, the latter is often more advantageous than the former. (3) The plurality of wheels include a driving wheel driven by a driving device of a vehicle, and a non-driving wheel not driven by the driving device, and the traveling speed obtaining device is configured to control the driving wheel by the inoperative brake detecting device. When both the brake corresponding to the non-drive wheel and the brake corresponding to the non-drive wheel are detected to be inoperative brakes, the traveling speed is obtained based on the rotation speed of the non-drive wheel. Or the vehicle described in (2) (Claim 3). The drive wheels are easily affected by the components of the drive device, for example, the engine and transmission (drive slip, engine brake, vibration, etc.), and accordingly, the traveling speed of the vehicle obtained based on the rotation speed of the drive wheels is While the accuracy is low, if it is a non-drive wheel,
The traveling speed can be detected with higher accuracy without being affected by the vibration of the components of the drive device. (4) At least a part of the plurality of brakes is an electric brake operated by an electric actuator.
The vehicle according to any one of paragraphs (1) to (3). Since the electric actuator is provided for each brake, it is easy to operate only one or a part of the plurality of brakes, and only one or a part of the brakes is inoperable. The possibilities are generally greater than for hydraulic brakes with hydraulically operated brake cylinders. Therefore, the effects of the present invention can be particularly effectively enjoyed. It is also possible to connect a dedicated pressurizing cylinder to the brake cylinder of each brake and drive the pressurizing piston of the pressurizing cylinder by a dedicated electric motor. In this case, a type of hydraulic brake is used. However, it is considered that the brake cylinder and the pressurizing cylinder and the fluid passage connecting them constitute a transmission device that transmits the driving force of the electric motor to the friction member through the working fluid, and is a type of electric brake. It is also possible to think. For example, if the pressurizing cylinder and the electric motor are provided on the vehicle body side from the suspension device, the brake cylinder is provided on the wheel side, and the liquid passage is formed by a flexible tube such as a rubber hose, the electric motor is provided on the wheel side. Thus, the mass moving integrally with the wheels can be reduced. (5) at least a part of the plurality of brakes includes a hydraulically operated brake cylinder; and
A brake operation member operated by a driver, at least one power hydraulic pressure source having a pump for pumping hydraulic fluid, and a brake cylinder for the brake cylinder based on a hydraulic pressure of the power hydraulic pressure source. The vehicle according to any one of (1) to (4), further including: a hydraulic pressure control device configured to control a hydraulic pressure to a size corresponding to an operation amount of the brake operation member. The hydraulic pressure control device may control the hydraulic pressure of the brake hydraulic cylinder by controlling the pump to control the hydraulic pressure of the power hydraulic pressure source itself. The hydraulic pressure of the brake cylinder may be controlled by changing the size to a value corresponding to the pressure (can be reduced or increased). A plurality of brake cylinders may be divided into a plurality of groups, and a dedicated power hydraulic pressure source may be provided for each group.
One may be provided. The brake operation amount may be the operation force of the brake operation member, the operation stroke, the operation continuation time, or the like. When there is a cause on the brake control device side that some of the plurality of brakes become inoperative brakes, the cause is various depending on the power hydraulic pressure source which is a component of the brake control device, the configuration of the hydraulic pressure control device, and the like. In the manner described above. For example, if the hydraulic pressure control device individually controls the hydraulic pressures of a plurality of brakes, a part of the plurality of brakes becomes an inoperative brake due to a failure of a part of the hydraulic pressure control device. Regardless of the cause of the inoperative brake, if an inoperative brake is generated in some of the brakes, the braking force is wasted based on the rotational speed of the wheel corresponding to the inoperative brake. Therefore, the traveling speed of the vehicle can be accurately obtained. (6) At least a part of the plurality of brakes includes a hydraulically operated brake cylinder, and
The brake control device controls the hydraulic pressure of the brake cylinder based on at least one power hydraulic pressure source including a pump that pumps hydraulic fluid, and the hydraulic pressure of the power hydraulic pressure source according to the traveling state of the vehicle. The vehicle according to any one of (1) to (5), including a hydraulic pressure control device for controlling the size of the vehicle. According to the features described in this section, traction control that prevents the wheel slip (slip amount, slip rate) from being excessive due to the wheel drive torque being excessive in relation to the road surface friction coefficient, It is possible to perform vehicle stability control or the like that activates a brake in order to improve the running stability of the vehicle, and according to the present invention, it is possible to accurately obtain the running speed required in that case. (7) At least a part of the plurality of brakes includes a hydraulically operated brake cylinder, and
The brake control device corresponds to each of a brake operating member operated by a driver, a master cylinder that generates a hydraulic pressure according to an operating force of the brake operating member, and supplies the hydraulic pressure to the brake cylinder, And a hydraulic pressure control valve device for controlling the hydraulic pressure of each brake cylinder to a magnitude different from the hydraulic pressure of the master cylinder. Vehicle. The master cylinder may or may not include a booster, such as a vacuum booster or a hydraulic booster, that boosts the brake operating force. According to the features described in this section, for example, antilock control, traction control, vehicle stability control, and the like can be performed. According to the present invention, the traveling speed required in that case is accurately acquired. be able to.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings, taking an example in which the present invention is applied to a vehicle having an electric brake system. In FIG. 1, reference numeral 10 denotes a brake control device, which controls four electric brakes 12, 14, 16, and 18, which are control target devices. These brake control device 10 and electric brakes 12, 14, 16, 1
8 is supplied with current from two batteries 20, 22 as power supply devices. The batteries 20 and 22 are provided independently of each other. Electric brakes 12, 14, 16, 18
Are left and right front wheels 24 and 26 and left and right rear wheels 2 respectively.
8, 30 are provided. In the present embodiment,
The left and right front wheels 24 and 26 are drive wheels, respectively, and the left and right rear wheels 2
The left and right front wheels 24 and 26 are driven by, for example, a driving device (not shown) including an engine, and the left and right rear wheels 28 and 30 are not driven.
30 is not driven by the drive.

[0006] The electric brakes 12, 14, 16, 18 are electric rotary motors (hereinafter abbreviated as motors) 32, 3 as electric motors which are a kind of electric actuators, respectively.
4, 36, 38, and motors 32, 34, 36, 38
The pressing member is moved by the drive of, and the friction material is pressed against the rotating body that rotates together with the wheel, thereby suppressing the rotation of the wheel. The electric brakes 12, 14, 16, 18 are friction brakes. Motors 32, 34, 36, 3
8 is constituted by, for example, a brushless DC motor. In FIG. 1, FL and FR are respectively left and right.
The right front wheels 24 and 26 are shown, and RL and RR represent left and right rear wheels 28 and 30, respectively. Electric brakes 12, 14, 1
6 and 18, the pressing force applied to the friction material by the pressing member is detected by the pressing force sensor 40,
The current supplied to the motors 32, 34, 36, 38 is detected by the current sensor 42, and the motors 32, 34, 36, 3
The relative position of the rotor with respect to the stator 8 is a position sensor 4
4 is detected.

The brake control device 10 includes a central control device 5
Motor control device 5 which is a kind of 0, 4 tip control devices
2, 54, 56, 58 and an input device 60. The input device 60 includes two stroke sensors 62 and 64 as operation amount sensors and two pedaling force sensors 66 and 68, respectively.
including. Each of the stroke sensors 62 and 64 independently generates an electric signal corresponding to a depression stroke which is an operation stroke which is an operation amount of a brake pedal 70 which is a brake operation member which is depressed by the driver, and the depression force sensors 66 and 68. Respectively generate electric signals corresponding to the pedaling force, which is the operation force that is the operation amount of the brake pedal 70, independently of each other.

The characteristics of the two stroke sensors 62, 64 and the pedaling force sensors 66, 68 are different from each other as shown in FIG. Stroke sensor 62,
The gain and offset are different from each other, and the stroke sensors 62 and 6 are different from each other.
The four (4) have different polarities (positive / negative of the gradient), and the pedaling force sensors 66 and 68 have different polarities. Therefore, the four sensors 62, 64, 66, 68
Are normal, the detection signals of the sensors 62 to 68 are all different signals, and the operation amounts obtained based on the detection signals are the same. The depression stroke and the depression force of the brake pedal correspond one-to-one, and the depression stroke and the depression force corresponding to each other are obtained. In FIG. 3, four sensors 62, 64, 66,
The manipulated variables obtained for each of the 68 detected values are all shown as pedaling forces.

If any one of the four sensors 62, 64, 66, 68 fails, only the pedaling force (operating amount) obtained by the detection signal of the failed sensor is obtained by the detection signals of the other three sensors. Since it is different from the treading force (operation amount) to be applied, it can be understood that a sensor having a different treading force (operation amount) is out of order. Further, since the four sensors 62 to 68 have different characteristics from each other as described above, even if the two sensors fail in the same mode, the pedaling force (the operation force) obtained by each detection signal of the two failed sensors. Two sensors having the same pedaling force (operating amount) obtained by the detection signal are normal, and two sensors having no sensor indicating the same pedaling force (operating amount) fail. You can see that it is doing. For failures of the same mode, for example,
As will be described later, in two sensors to which the same battery is connected, there is a failure in which the gain decreases when the voltage of the battery decreases. Furthermore, four sensors 62,
If three or more of the sensors 64, 66, and 68 fail, there is no treading force (operation amount) having the same value, and the failed sensor cannot be specified, so that the brake control device 10 cannot operate.

As shown in FIG. 1, the central control unit 50
It has two microcomputers 80 and 82. Among these microcomputers 80 and 82, the microcomputer 80 includes the electric brakes 12, 14, 16, 1
The microcomputer 82 is a monitoring computer that monitors an abnormality of the microcomputer 80. Hereinafter, the microcomputer 80 is referred to as a main microcomputer 80, and the microcomputer 82 is referred to as a monitoring microcomputer 82.

The main microcomputer 80 includes power supply ICs 84 and 86
The batteries 20 and 22 are connected by the power supply ICs 88 and 90 to the monitoring microcomputer 82.
22 are connected. All (two in the present embodiment) batteries 20, 22 are connected to the main microcomputer 80 and the monitoring microcomputer 82, respectively.

In this embodiment, the monitoring microcomputer 82 outputs a watchdog pulse to the main microcomputer 80 at regular time intervals to monitor the main microcomputer 80 for abnormalities. In the main microcomputer 80, processing for controlling the electric brakes 12, 14, 16, and 18 is executed, and an interrupt is performed for the processing. If the main microcomputer 80 is normal, the watchdog The response pulse to the pulse is sent from the main microcomputer 80 to the monitoring microcomputer 82.
Supplied to This indicates that the main microcomputer 80 is normal. Conversely, in the main microcomputer 80, whether or not the monitoring microcomputer 82 is normal can be determined based on whether or not the watchdog pulse is supplied from the monitoring microcomputer 82.

The detection signals of the stroke sensor 62 and the pedaling force sensor 66 are input to the main microcomputer 80 by an input IC 94, and the detection signals of the stroke sensor 64 and the pedaling force sensor 68 are input by an input IC 96. The main microcomputer 80 also has another input IC 98,
100, a signal corresponding to each rotational speed of the left and right front wheels 24, 26 and the left and right rear wheels 28, 30 is output,
Wheel speed sensors 112 and 11 for detecting rotation speeds respectively
4, 116, 118, diagnostic information of the failure diagnostic device 119, a signal of an accelerator switch 124 for detecting depression of an accelerator pedal (not shown), a brake pedal 70
, A detection signal of a G sensor for detecting acceleration in front, rear, and side of the vehicle, a steering angle, a yaw rate, engine information, and the like. The accelerator switch 124 is configured to output different signals when the accelerator pedal is depressed and when the accelerator pedal is not depressed. In the present embodiment, the accelerator switch 124 outputs an ON signal when the accelerator pedal is depressed. When the pedal is not depressed, an OFF signal is output. The stop switch 125 is configured to output different signals when the brake pedal 70 is depressed and when it is not depressed. In the present embodiment, the stop switch 125 is turned off when the brake pedal 70 is depressed.
An N signal is output, and an OFF signal is output when the pedal is not depressed.

The central control unit 50 and the motor control unit 52,
54, 56, 58, the CAN (Car Area)
Network) 102, 104, 106, 108, 110 perform communication. In CAN communication, a plurality of pieces of information transmitted in one direction can be transmitted in a superimposed manner, or information transmitted in both directions can be transmitted simultaneously, and a large amount of information can be transmitted in a short time. It is possible.

The main microcomputer 80 includes a stroke sensor 6
2, 64, and the pressing force of each pressing member of the electric brakes 12, 14, 16, 18 pressing the friction material against the rotating body based on the detection signals of the pedaling force sensors 66, 68, respectively, and the CAN 102, 104, 106, The pressurized force command value is set by the motor control devices 52, 54, 56,
58. This calculation is performed in principle so that the target pressing force corresponds to the treading force detected by the treading force sensors 66 and 68. However, since the increase in the treading force is delayed with respect to the depression operation of the brake pedal 70, the stroke sensor 6
The calculation is performed in consideration of the depression stroke of the brake pedal 70 detected by the brake pedal 2 and the brake pedal 64. This calculation is performed such that the longer the elapsed time from the start of depression of the brake pedal 70, the smaller the contribution of the depression stroke to the target pressing force. If both sensors of the same type are normal, two detection signals of the same type are obtained. In the present embodiment, for example, the average of the two detection signals is used for the calculation. Which sensor's detection signal is used for calculation may be set in advance.

The main microcomputer 80 also includes sensors 62, 6
If there is a fault in 4, 66, 68, the faulty sensor is specified, and if there is one or two faulty sensors, the pressure indication value is obtained using only the detection signal of the normal sensor. Calculate and notify the failure by lighting the lamp. If three or more sensors are out of order and the brake control device 10 is inoperable, a notification is made by turning on a lamp and sounding a buzzer. The lamp and the buzzer constitute a failure notification device. The program for calculating the target pressure is the sensor 6
If 2, 64, 66 and 68 are normal, as described above,
The target pressure is calculated based on the two types of detection signals, and even if the sensor fails, at least one of the stroke sensors 62 and 64 and one of the pedaling force sensors 66 and 68 are normal, or the stroke sensor 62 , 64 and at least one of the treading force sensors 66, 68 are normal, or if one of the stroke sensors 62, 64 and one of the treading force sensors 66, 68 are normal, a normal The target pressing force is calculated based on the stepping stroke and the stepping force obtained by the sensors, and either the two stroke sensors 62 and 64 fail or the stepping force sensors 66 and 68 both fail and either the stepping stroke or the stepping force is applied. When only the value can be obtained, the target pressure is calculated using the obtained value.

The ROM of the main microcomputer 80 includes a vehicle running speed acquisition routine shown in the flowchart of FIG. 7, a main routine (not shown), a normal braking control routine, an antilock control routine, a traction control routine, and a vehicle stability control routine. Various routines are stored. The main microcomputer 80 performs normal braking control, antilock control, traction control, vehicle stability based on detection signals from the wheel speed sensors 112 to 118, the G sensor, and the like in addition to the stroke sensors 62 and 64, the pedaling force sensors 66 and 68. Electric brake 12 such as control
Various controls using １８18 are performed. Commands necessary for control are created and output to the motor control devices 52 to 58 to control the electric brakes 12 to 18.

The motor control devices 52, 54, 56, 5
8 are electric brakes 12, 14, 16, and 18 for braking left and right front wheels 24, 26 and left and right rear wheels 28, 30, respectively.
The eighteen motors 32, 34, 36, 38 are controlled. These motor control devices 52, 54, 56, 58 are basically configured in the same manner. The motor control device 52 that controls the electric brake 12 that brakes the left front wheel 24 will be described as a representative, and other Motor control devices 54, 56, 58
Will be described individually.

As shown in FIG. 1, the motor control device 52 includes two microcomputers, ie, a motor 32.
And a monitoring microcomputer 122 for monitoring the main microcomputer 120 (hereinafter, simply referred to as a monitoring microcomputer 122). Main microcomputer 120
, The input pressure IC 126 allows the pressure sensor 40,
The detection signals of the current sensor 42 and the position sensor 44 are input, and the input signals of the stroke sensor 62 and the pedaling force sensor 66 are input by the input IC 128. Further, the CAN 1 for communicating with the central controller 50.
04. The main microcomputer 120 determines the drive current of the motor 32 and the like based on the pressing force instruction value (target pressing force) supplied from the central control device 50 and the detection signals of the pressing force sensor 40, the current sensor 42, and the position sensor 44. Then, the motor 32 is controlled via the motor drive IC 132.

The monitoring microcomputer 122 sends a watchdog pulse to the main microcomputer 12 similarly to the monitoring microcomputer 82.
0, and detects whether or not the main microcomputer 120 is normal based on whether or not there is a response from the main microcomputer 120.
The main microcomputer 1 determines whether or not the monitoring microcomputer 122 has failed.
20. The motor control device 52 is provided with a power supply IC 136 and connected to the battery 20. Battery 20 is also connected to motor 32. The monitoring microcomputer 122 controls the semiconductor relay 138 to allow and cut off the supply of current from the battery 20 to the motor 32.

The motor control device 54 has the same components as the motor control device 52 except that the stroke sensor 6
4 and the treading force sensor 68 are connected, and the battery 22 is connected. Motor controller 56
Are the same as the motor control device 54 with respect to the components, the connected sensors, and the battery.
Are the same as those of the motor control device 52 in all of the components, connected sensors, and batteries. Of the two independent batteries 20, 22, the battery 20 is connected to the motor control devices 52, 58 corresponding to the left front wheel 24 and the right rear wheel 30, one of the two sets at diagonal positions of the vehicle,
The battery 22 is connected to motor control devices 54 and 56 corresponding to the other of the two right and left rear wheels 28 at the diagonal positions of the vehicle. Further, two pairs of stroke sensors 62 and 64 and a tread force sensor 6 are provided.
6 and 68 are all connected to the central control device 50, and the stroke sensor 62 and the pedaling force sensor 66 are one of two sets located at diagonal positions of the vehicle.
, And the stroke sensor 64 and the pedaling force sensor 68 are connected to the right front wheel 26 and the left rear wheel 2 which are the other of the two sets at the diagonal positions of the vehicle.
8 are connected to the motor control devices 54 and 56 corresponding to.

Further, the main microcomputer 120 of the motor control device 52 provided corresponding to the left front wheel 24 and the right front wheel 26
Are connected to each other and the main microcomputer 120 of the motor control device 54 is provided correspondingly, and information is transmitted and received by serial communication. Serial communication is communication in which a large amount of information can be mutually communicated by one communication line by a digital signal.

The connection of the batteries 20, 22 to the stroke sensors 62, 64 and the pedaling force sensors 66, 68 will be described with reference to FIG. As shown in FIG. 2, the battery 22 is connected to the stroke sensor 62 and the pedaling force sensor 66 via the central control device 50, and the battery 20 is connected to the motor control device 52. The stroke sensor 62 and the pedaling force sensor 66 supply a monitor current indicating that a current is supplied to them to each ADC (A) of the central control device 50 and the motor control devices 52 and 58.
D converter) 142, 144, 150. A
The detection signals of the stroke sensor 62 and the pedaling force sensor 66 are also input to the DCs 142, 144, and 150.

The battery 20 is connected to the stroke sensor 64 and the pedaling force sensor 68 via the central control device 50, and the battery 22 is connected to the stroke sensor 64 and the pedaling force sensor 68, respectively. The central control unit 50 and the motor control unit 5 supply a monitor current indicating that current is supplied to them.
4 and 56 to the ADCs 142, 146, and 148, respectively. These ADCs 142, 146, 148 also
Detection signals from the stroke sensor 64 and the pedaling force sensor 68 are input.

In the vehicle including the electric brake system configured as described above, if the brake pedal 70 is depressed, the stroke sensors 62 and 64 and the pedal force sensor 6
The main microcomputer 80 of the central control device 50 calculates the target pressing force of each of the electric brakes 12, 14, 16, 18 based on the stepping stroke and the stepping force detected by the motor control devices 52 to 58. Output. The motor control devices 52 to 58 determine the driving amounts of the motors 32 to 38 based on the pressing force instruction value and the detection signal of the pressing force sensor 40 and the like, and control them via the motor driving IC 132.
As a result, the motors 32 to 38 are operated, and the pressing member moves to press the friction material against the rotating body, and the wheels 24 to 30 are driven.
Is suppressed. Then, when the pressure applied to the friction material in the electric brake is excessive in relation to the friction coefficient of the road surface, the antilock control is performed. In a state where the left and right front wheels 24 and 26 are driven by the driving device, if the driving force is excessive with respect to the road surface friction coefficient, traction control is performed. Further, vehicle stability control is performed as needed.

If a failure occurs, the vehicle is braked according to the failure control modes shown in FIGS.
The failure is caused by the electric brake 1
It also occurs on the 2-18 side. For example, the central controller 50
Failure occurs due to failure of at least one of the main microcomputer 80 and the monitoring microcomputer 82. Also, the motor control devices 52 to 5
8 is, for example, a main microcomputer 120 and a monitoring microcomputer 122
, A failure of the motor drive IC 132, a failure of the batteries 20, 22, a failure of the semiconductor relay 138, a failure of the sensors 62, 64, 66, 68, and the like. As described above, the failure of the main microcomputer 120 and the monitoring microcomputer 122 is detected based on the watchdog pulse.
It can be seen from the fact that no voltage is applied to C136. Also,
When a voltage is applied to the power supply IC 136 and the motor drive I
If no current is detected by the current sensor 42 even though the motor drive signal is output to C132,
The semiconductor relay 138 or the motor drive IC 132 has failed. The failure of the sensors 62, 64, 66, 68 can be understood from the fact that no detection signal is input to the input IC 128.

The electric brakes 12 to 18 fail due to, for example, failure of the motors 32 to 38. Motors 32-38
Is detected based on the detection signal of the pressure sensor 40 and the like and the target pressure. For example, even if a command to increase the motor drive current is output to increase the pressing force, if the pressing force does not increase, the motors 32 to
38 failures. The motors 32 to 38 are operated, and the pressure is actually measured by a pressure sensor as an amount related to the braking force to detect a failure.

If the electric brakes 12 to 18 themselves fail, they become inoperable brakes which are inoperable brakes. If the corresponding motor control devices 52 to 58 fail, operation is commanded by the motor control devices. It is an operation command impossible brake that cannot be operated due to the cause of the brake control device 10 side.
A non-operating brake that does not operate even though it should operate. In the present electric brake system, the motors 32 to 38 and the motor control devices 52 to 58 are provided for each of the electric brakes 12 to 18, and one of the electric brakes 12 to 18 may become an inoperative brake. , More than one may be inoperative brakes.

In this embodiment, both the failure of the brake control device 10 and the failure of the electric brakes 12 to 18 are determined in advance by the failure diagnosis device 119 (see FIG. 1) provided in the vehicle, that is, the electric brake 12 18 is detected before it is necessary to suppress the rotation of the wheels, and for which wheel the electric brake is the inoperative brake is provided in the RAM of the main microcomputer 80 of the central control device 50. It is stored in the failed wheel memory 160 (see FIG. 8). In the sense that the rotation of the wheel cannot be suppressed, the wheel whose electric brake provided is an inoperative brake is a failed wheel, and is stored in the failed wheel memory 160.

The control modes at the time of failure shown in FIGS. 4 to 6 are not disclosed yet, but are the same as the brake system described in the specification of Japanese Patent Application No. 11-248874 filed by the present applicant. Therefore, some control modes will be described representatively, and description of other control modes will be omitted.
4 to 6, the system ECU represents the central control device 10, the motor ECU represents the motor control device, and FL, FR, RL, RR represent left and right front wheels 24, 26, left, and right, respectively. Represent the rear wheels 28, 30.

For example, as shown in the column of "one failure" in FIG. 4, only the central control unit 50 fails and the motor control unit 5 fails.
When the motors 2 to 58 and the motors 32 to 38 do not fail, the motor control devices 52 to 58 receive the respective detection signals of one of the stroke sensors 62 and 64 and one of the pedaling force sensors 66 and 68, respectively. Motor control device 5
Each of 2 to 58 can calculate the pressing force instruction value by itself based on the detection signal, and can control the motors 32 to 38 based on the pressing force instruction value and the detection signal of the pressing force sensor 40 and the like. , Normal performance, ie central control unit 5
The same performance is obtained as if 0 were not faulty. In addition,
In the present embodiment, when the central control device 50 fails, the antilock control, the traction control, and the vehicle stability control are not performed.

If a failure occurs in at least one of the motor control device and the motor for one wheel, for example, if the motor control device 52 provided for the left front wheel FL fails, the central control device 50 ,
The operation modes of the motor control devices 54, 56, 58 are determined. In this case, the operation of the motor control device 58 corresponding to the right rear wheel 30 at the diagonal position of the vehicle is prohibited for the left front wheel 24 corresponding to the motor control device 52, and the remaining two motor control devices The pressing force values calculated in the same manner as in the normal state are supplied to 54 and 56 to control the motors 34 and 36. The rotation of each of the right front wheel 26 and the left rear wheel 28 at the diagonal position of the vehicle is suppressed in the same manner as in the normal state. By executing this diagonal wheel control, a maximum deceleration of 0.5 G can be obtained. .

As shown in FIG. 5, when a failure occurs in at least one of the motor control device and the motor for the two wheels, for example, the left and right front wheels FL, FR
When the motor control devices 52 and 54 provided for the first and second motors fail, the central control device 50
The pressure command values calculated in the same manner as in the normal state are output to the motors 6 and 58, and the motors 36 and 38 are controlled. As a result, the electric brakes 16 and 18 operate and the electric brakes 12 and 14 do not operate. In this case, a maximum deceleration of 0.3 G is obtained.

Further, as shown in FIG. 6, when a failure occurs in at least one of the motor control device and the motor for three wheels, for example, the left and right front wheels FL, F
If the motor control devices 52, 54, 56 provided for the R and the left rear wheel RL fail, only the motor control device 58 operates to control the motor 38, and a deceleration of up to 0.15 G for the entire vehicle But you can get
It is not sufficient for braking the vehicle, and the driver is notified of the stop of the vehicle and the failure of the brake control device 10 by turning on a lamp constituting a failure notification device and sounding a buzzer. In any of the above cases, for the inoperative brake, the semiconductor relay 138 is opened and the current supply is cut off.

Next, the acquisition of the vehicle traveling speed based on the vehicle traveling speed acquisition routine shown in the flowchart of FIG. 7 will be described. The vehicle running speed acquisition routine is repeatedly executed by turning on an ignition switch of the vehicle. First, in step 1 (hereinafter referred to as S1; the same applies to other steps), it is determined whether or not there is a lost wheel. This determination is based on the failure wheel memory 160
Is read out, and if there is no failure, S1
Is NO, S2 is executed, and the traveling speed of the vehicle is obtained. The peripheral speeds of the four wheels 24 to 30 are calculated based on the detection signals of the wheel speed sensors 112 to 118, and the traveling speed of the vehicle is obtained by a normal method based on the peripheral speeds. It is memorized.

On the other hand, if there is a lost wheel, the result of determination in S1 is YES and S3 is executed to determine whether or not the brakes are being operated, that is, at least one of the electric brakes 12 to 18 is operated. It is determined whether or not braking is being performed. In this embodiment, this determination is made based on whether or not at least one of depression of the brake pedal 70, traction control, and vehicle stability control is performed. The determination as to whether or not the brake pedal 70 is depressed is made based on, for example, a signal from the stop switch 125 that detects the depression of the brake pedal 70. Stroke sensors 62, 64,
The depression of the brake pedal 70 may be detected based on the detection signals of the depression force sensors 66 and 68. The execution of the traction control and the vehicle stability control can be understood, for example, by storing the execution of the control by setting a flag in a program for performing the control. The determination as to whether or not the brake is operated when the brake pedal 70 is not depressed is performed, for example, by executing an automatic brake control or the like that detects a distance to a vehicle traveling ahead and automatically activates the brake. It may be performed depending on the presence or absence.

If none of the electric brakes 12 to 18 is operated, the determination result in S3 is NO, and
4 is performed, and it is determined whether or not the failed wheel is a non-drive wheel. At this time, if there is one failed wheel, it is determined whether or not the wheel is a non-driving wheel. If there are a plurality of failed wheels, it is determined whether or not each wheel is a non-driving wheel. You. If all the lost wheels are drive wheels and there is no non-drive wheel that is a lost wheel, the determination result in S4 is NO and S5 is executed, and the peripheral speeds of the four wheels 24 to 30 are determined. Is calculated, and the minimum peripheral speed among the peripheral speeds is set as the traveling speed of the vehicle, and is stored in the vehicle traveling speed memory 162. When none of the electric brakes 12 to 18 is actuated and the failed wheel is a driving wheel, no braking slip occurs. However, if driving is performed, a driving slip occurs. In the case of a fall, the vehicle traveling speed acquisition wheel is not immediately set, and the minimum value of the peripheral speeds of the four wheels is acquired as the traveling speed of the vehicle. Here, the drive slip is a positive slip, that is, a slip in which the wheel speed is greater than the traveling speed of the vehicle,
It is assumed that the braking slip is a negative slip, that is, a slip in which the wheel speed is lower than the running speed of the vehicle.
The same applies to the following description.

In addition, at least one of all the failed wheels
If one is a non-driving wheel, the result of the determination in S4 is YES and S7 is executed. The traveling speed of the vehicle is calculated based on the peripheral speed, and is stored in the vehicle traveling speed memory 162. At this time, if there is one non-driving wheel, the peripheral speed is taken as the traveling speed of the vehicle. If there are two non-driving wheels, for example, the average value of each peripheral speed is calculated and the traveling speed of the vehicle is calculated. Speed.

If there is a lost wheel and the brake is being operated, the determination results in S1 and S3 are both YES, and S6 is executed to determine whether the failed wheel is a non-drive wheel. A determination is made. This determination is performed in the same manner as in S4. If at least one of all the failed wheels is the non-drive wheel, the determination result in S6 becomes YES and S7 is performed. Also, if all the lost wheels are driving wheels,
The determination result of S6 is NO, and S8 is executed, and it is determined whether or not the accelerator pedal is depressed.
This determination is made based on the output signal of the accelerator switch 124. If the akle pedal is not depressed,
The determination result in S8 is NO, and S9 is executed. In this case, the failed wheel, that is, the drive wheel where the electric brake does not operate, is the drive wheel, but since the accelerator pedal is not depressed and is not driven, neither a drive slip nor a braking slip occurs, and the detection of the wheel speed sensor is performed. The peripheral speed of the failed drive wheel is calculated based on the signal, the traveling speed of the vehicle is acquired based on the peripheral speed, and stored in the vehicle traveling speed memory 162. At this time, if there are two failed drive wheels, for example, the average value of the peripheral speeds of the respective wheels is calculated and used as the running speed of the vehicle.

If the accelerator pedal is depressed, S
8 is YES, and S10 is executed.
The traveling speed of the vehicle is acquired based on rules other than the vehicle traveling speed acquisition rules in 5, S7, and S9. For example, if there is a non-drive wheel where the electric brake is not activated,
The running speed of the vehicle is obtained based on the rotation speed of the non-driven wheels. This is because neither the driving slip nor the braking slip occurs for such non-driven wheels.

The running speed of the vehicle thus obtained is
For example, it is used for antilock control. If none of the four electric brakes 12 to 18 are inoperative brakes and there is no wheel failure, normal antilock control is performed using the vehicle traveling speed acquired in S2 of the vehicle traveling speed acquisition routine. In contrast, four electric brakes 1
If at least one of the brakes 2 to 18 is an inoperative brake and there is a lost wheel, the antilock control is performed using the vehicle traveling speed acquired in S7 or S9. If there is a lost wheel, the actual slip ratio is calculated for each wheel using the vehicle traveling speed acquired in S7 or S9, and the target pressing force is set so that the actual slip ratio becomes the target slip ratio. The target slip rate is set to a value at which the maximum friction coefficient is obtained. In the present embodiment, for example,
It is set to 0.25.

At the time of traction control, if there is no lost wheel, control is performed using the vehicle traveling speed acquired in S2, and if there is a lost wheel, the vehicle traveling acquired in S7, S9 or S10 is performed. Control is performed using speed. The same applies to vehicle stability control.

As is apparent from the above description, in the present embodiment, the failure diagnosis device 119, which is a failure detection device or a failure detection device, constitutes an inoperative brake detection device including an operation command disabled brake detection unit, The portion of the control device 50 that executes S3, the sensors 62 to 68, and the like constitute a braking detection device or a brake operation detection device, and the portion of the central control device 50 that executes S7 and S9, and the wheel speed sensor 1
12 to 118 constitute a traveling speed acquisition device.

In the above embodiment, when there is a lost wheel, even if the brake pedal 70 is not depressed, if at least one of the electric brakes 12 to 18 is operated, the rotational speed of the failed wheel is reduced. The travel speed of the vehicle is obtained based on the brake pedal 7.
The running speed of the vehicle may be acquired based on the rotational speed of the failed wheel only when the stepping operation of “0” is performed.
An example is shown in FIG. The vehicle according to the present embodiment is configured in the same manner as the vehicle according to the above-described embodiment except that anti-lock control is performed, but traction control and vehicle stability control are not performed, and the configuration of a vehicle traveling speed acquisition routine is performed. I have.

The acquisition of the vehicle traveling speed based on the vehicle traveling speed acquisition routine will be described. First, in S21, it is determined whether or not there is a lost wheel. This determination is performed in the same manner as in S1 of the above-described embodiment.
The determination result at 21 is NO, and S22 is executed to acquire the traveling speed of the vehicle. The traveling speed of the vehicle is obtained by a normal method. For example, when the accelerator pedal is depressed, the peripheral speeds of the four wheels 24 to 30 are calculated based on the detection signals of the wheel speed sensors 112 to 118. At the same time, the minimum peripheral speed is selected from the peripheral speeds and is set as the traveling speed of the vehicle.
M is stored in a vehicle traveling speed memory 162 provided in M. Also, when the brake pedal 70 is depressed,
In principle, the maximum peripheral speed among the peripheral speeds of the four wheels 24 to 30 is selected and stored as the traveling speed of the vehicle, and the deceleration of the wheel having the maximum peripheral speed exceeds the set deceleration. Then, if the value obtained by reducing the vehicle running speed at the time when the speed exceeded the predetermined gradient is assumed to be the vehicle speed, and if a wheel whose wheel speed exceeds the estimated vehicle speed occurs among the four wheels, The peripheral speed of the wheel is set as the traveling speed of the vehicle.

If there is a lost wheel, the judgment result in S21 is YE
In S, S23 is executed to determine whether or not the brake is operated, that is, whether or not the brake pedal 70 is depressed. Whether or not the brake pedal 70 is depressed is determined by, for example, the stop switch 1
This is performed based on 25 output signals. Brake pedal 7
If 0 has not been depressed, the determination result of S23 is NO.
Then, S24 is executed in the same manner as in S4, and if all the failed wheels are the driving wheels, S25 is executed in the same manner as in S5. If at least one of the lost wheels is a non-drive wheel, S27 is executed in the same manner as in S7, and the traveling speed of the vehicle is acquired.

If the brake pedal 70 is depressed, the result of the determination in S23 is YES, and S26 is executed to determine whether or not there is a non-driving wheel among all the failed wheels. If at least one lost wheel is a non-drive wheel, S27 is executed to acquire the traveling speed of the vehicle.
If all the lost wheels are drive wheels, the determination result in S26 is NO, and S28 is executed in the same manner as in S9. Since the brake pedal 70 has been depressed and the accelerator pedal has not been depressed, neither a drive slip nor a braking slip has occurred on the drive wheel that has failed, and the peripheral speed of the non-drive wheel that has failed has been reduced. The calculation is performed, and the traveling speed of the vehicle is obtained.

In this embodiment, the central control unit 50
And the sensors 62 to 68 constitute a brake operation detecting device.
7, the part executing S29 and the wheel speed sensors 112 to
Reference numeral 118 denotes a traveling speed acquisition device.

Although the traction control and the vehicle stability control are not performed in the above embodiment, they may be performed.
When traction control is performed, the brake pedal is not depressed and the accelerator pedal may be depressed or not depressed, but the traction control is performed on the drive wheels, so the failed wheel If is a non-driving wheel, no driving slip or braking slip occurs, and the running speed of the vehicle may be obtained based on the rotational speed of the non-driving wheel which is a failed wheel. Further, if the lost wheel is a driving wheel, traction control is not performed even if necessary, and the driving slip may be large. In this case, the minimum peripheral speed of the four wheels is set to the minimum peripheral speed of the vehicle. If the traveling speed is used, the peripheral speed of the wheel where the drive slip occurs is not used as the traveling speed of the vehicle, and there is no problem in obtaining the traveling speed of the vehicle according to the rule. If there is a normal drive wheel, if traction control is required for that drive wheel, the brake is actuated, and the drive slip is excessive or the drive slip is reduced by suppressing the rotation of the wheel. Therefore, there is no problem in obtaining the traveling speed of the vehicle. When the vehicle stability control is performed, both the brake pedal and the accelerator pedal may be depressed or may not be depressed.
In the state where the brake pedal is not depressed, if the lost wheel is a non-driving wheel, vehicle stability control is not performed even if it is necessary, and neither driving slip nor braking slip occurs. The traveling speed of the vehicle may be obtained based on the rotation speed of the drive wheels. In addition, when the failed wheel is a drive wheel, a drive slip occurs when the accelerator pedal is depressed, and a drive slip occurs when the vehicle stability control is not performed for a normal drive wheel. If the vehicle stability control is performed, a driving slip or a braking slip occurs. If the vehicle stability control is performed for the non-driven wheels, a braking slip occurs. If the accelerator pedal is not depressed, no drive slip or braking slip will occur on the failed drive wheel, and braking will be performed on normal drive wheels and non-drive wheels if vehicle stability control is performed. Slip occurs. However, the driving slip or the braking slip that occurs during the vehicle stability control is not so large that the peripheral speed of the wheel at which the slip occurs as a running speed of the vehicle is not large, and among the peripheral speeds of the four wheels, It is considered that the traveling speed of the vehicle may be acquired according to the rule that the minimum peripheral speed is set as the traveling speed of the vehicle. Also, if the brake pedal is depressed and the failed wheel is a non-driving wheel, vehicle stability control is not performed on the non-driving wheel that is a failed wheel even if vehicle stability control is required, and the driving slip is also a braking slip. Therefore, the peripheral speed of the non-driven wheel, which is a lost wheel, may be used as the traveling speed of the vehicle. If the failed wheel is a drive wheel, vehicle stability control is not performed on the failed drive wheel even if vehicle stability control is required, and no braking slip occurs.
Since the brake pedal is depressed and the accelerator pedal is not depressed, drive slip does not occur, and the peripheral speed of the failed drive wheel may be used as the traveling speed of the vehicle. Considering the above, even when the traction control and the vehicle stability control are performed, there is no problem even if the traveling speed of the vehicle is acquired by the vehicle traveling speed acquisition routine shown in FIG.

The present invention may be applied to a vehicle having a hydraulic brake system. An example thereof will be described with reference to FIGS. Reference numerals 200 and 202 indicate a front left wheel and a front right wheel, respectively, and reference numerals 204 and 206 indicate a rear left wheel and a rear right wheel, respectively. In this embodiment,
The left and right front wheels 200 and 202 are drive wheels, and the left and right rear wheels 20
4,206 are non-drive wheels. Front wheels 200, 20
2 is provided with a hydraulic brake having brake cylinders 210 and 212,
12 is actuated by supplying hydraulic pressure to the front wheels 20.
A braking torque is applied to 0,202. Rear wheels 204, 206
Similarly, a hydraulic brake having brake cylinders 214 and 216 is provided. Brake cylinder 210
To 216, the hydraulic pressure of the manual hydraulic pressure source 220 and the hydraulic pressure of the power hydraulic pressure source 222 are alternatively supplied.

The manual hydraulic pressure source 220 has a master cylinder 228 for generating a hydraulic pressure corresponding to an operation force which is an operation amount of a brake pedal 226 as a brake operation member. The master cylinder 228 is a tandem type,
The same amount of hydraulic pressure is generated in two independent pressurized chambers. The master cylinder 230 is provided with a master reservoir 230. When the brake pedal 226 is in the non-braking position and the pressurizing piston in the master cylinder 228 is at the retreat end position, the two pressurizing chambers of the master cylinder 228 communicate with the master reservoir 230,
When the pressurizing piston is slightly advanced from the retracted end position, the pressurizing chamber is shut off from the master reservoir 230. One pressurizing chamber is connected to the brake cylinder 21 by the liquid passage 240.
0, 212, and the other pressurizing chamber is connected to brake cylinders 214, 216 by a liquid passage 242. The liquid passages 240 and 242 are provided with master cylinder cut valves 244 and 246, each of which is a normally open solenoid valve.
Each of the hydraulic pressures on the brake cylinder 210 to 216 side from 246 is a brake cylinder hydraulic pressure sensor 250, 252, 25
4, 256, and the hydraulic pressure on the master cylinder 228 side is detected by the master cylinder hydraulic pressure sensor 258. Also, the brake pedal 226 and the master cylinder 22
8, a stroke simulator 260 is provided to give the driver a feeling similar to a brake operation in a normal hydraulic brake device without the power hydraulic pressure source 222.

The power hydraulic pressure source 222 includes a pump motor 268 as a driving source for driving the pump 266 and the pump 266, an accumulator 270, and the like. Pump 266
Is constituted by a gear pump, for example. Pump 26
6 pumps up the working fluid in the master reservoir 230 and stores it in the accumulator 270. The hydraulic pressure of the accumulator 270 is determined by the two pressure switches 27 whose detected hydraulic pressures are different from each other.
2, 274, and the accumulator 270 always stores the working fluid in the set pressure range. Sign 2
76 is a relief valve. The hydraulic pressure of the power hydraulic pressure source 222 is supplied to the brake cylinders 210 to 216 via the hydraulic passage 280 and detected by the pump hydraulic pressure sensor 282.

The pressure-increasing electromagnetic control valves 29, which are electromagnetic valves, correspond to the brake cylinders 210 to 216, respectively.
0, 292, 294, 296 and the pressure reducing electromagnetic control valve 29
8, 300, 302 and 304 are provided. FIG.
1 is an electromagnetic control valve 290 for increasing pressure and an electromagnetic control valve 2 for decreasing pressure.
98 is representatively shown. The pressure-increasing electromagnetic control valve 290 and the pressure-reducing electromagnetic control valve 298 have a structure schematically shown in FIG. 11, and are both normally closed seat valves. Pressure increasing solenoid control valve 2
90 includes a seat valve 314 including a valve seat 310 and a valve element 312 which can be seated and separated from the valve seat 310.
Is biased in the seating direction by a spring 316 as a biasing device. A movable core 318 is provided integrally with the valve 312, and a fixed core 320 is provided to face the movable core 318. These two cores 318 and 320 are connected to the spring 31.
6 are magnetized by supplying a current to the coil 322, and the movable core 318
Is attracted to the fixed core 320 side. Thereby, the valve 3
12 is separated from the valve seat 310, and the seat valve 314 is opened to establish a communication state in which the liquid passage 280 is communicated. The pressure-intensifying electromagnetic control valve 290 acts on the power hydraulic pressure source 222 and the brake cylinder 210 in a state where the differential pressure acting force based on the hydraulic pressure difference before and after the valve itself acts in a direction to separate the valve element 312 from the valve seat 310. It is connected. Therefore, the valve element 312 is configured such that the sum of the differential pressure acting force based on the hydraulic pressure difference between the front and rear of the seat valve 314 and the electromagnetic driving force of the solenoid 324 including the movable core 318, the fixed core 320, and the coil 322 is the urging force of the spring 316. Therefore, the opening of the seat valve 314 can be controlled by controlling the electromagnetic driving force by controlling the current supplied to the coil 322. The opening degree of the pressure-intensifying electromagnetic control valve 290 can be controlled, whereby the flow rate of the hydraulic fluid,
That is, the pressure increasing speed of the brake cylinder 210 can be controlled. Further, if the difference between the hydraulic pressure of the power hydraulic pressure source 222 and the hydraulic pressure of the brake cylinder 210 becomes small, and the sum of the differential pressure acting force and the electromagnetic driving force becomes slightly smaller than the urging force of the spring 316, the valve Since the seat 312 is seated on the valve seat 130 and the seat valve 314 is closed to shut off the fluid passage 280, the supply current to the coil 322 is controlled to control the fluid pressure of the power fluid pressure source 222 and the brake cylinder 210. The difference from the hydraulic pressure can be controlled.

Since the structure of the pressure reducing electromagnetic control valve 298 is the same as that of the pressure increasing electromagnetic control valve 290, the corresponding components are denoted by the same reference numerals, and description thereof will be omitted. However, the pressure-reducing electromagnetic control valve 298 is oriented so that the differential pressure acting on the basis of the difference between the hydraulic pressure of the brake cylinder 210 and the hydraulic pressure of the master reservoir 230 acts in a direction in which the valve 312 is separated from the valve seat 310. , The brake cylinder 210 and the master reservoir 230 are connected by a liquid passage 240 and a liquid passage 326. Therefore, by controlling the supply current to the coil 322, the pressure reduction speed of the brake cylinder 210 and the differential pressure between the brake cylinder 210 and the master reservoir 230 can be controlled. Since the hydraulic pressure of the master reservoir 230 can be substantially regarded as the atmospheric pressure, the control of the differential pressure between the brake cylinder 210 and the master reservoir 230 is the hydraulic pressure control of the brake cylinder 210 as it is.

Further, the master cylinder cut valve 24
4, 246 and normally open solenoid valves 330, 332 are provided between the brake cylinders 210, 214, respectively, to allow and shut off the communication between the brake cylinders 210, 212 and the brake cylinders 214, 216. Have been to be. Also, the brake cylinders 210, 21
A normally open solenoid valve 334 is provided between the brake cylinder 21 and the brake cylinders 214 and 216.
0, 212 and the brake cylinders 214, 216 are allowed and cut off. Reference numeral 338
When the hydraulic pressure of the power hydraulic pressure source 222 becomes smaller than the hydraulic pressure of the master cylinder 228 due to a failure or the like, the hydraulic fluid in the master cylinder 228 is increased in pressure and supplied to the brake cylinders 210 and 212.

The components described above are connected to the electronic control unit 340. Electronic control unit 340
Is constituted mainly by a computer, and in addition to the master cylinder hydraulic pressure sensor 258, a wheel speed sensor 34 that outputs a signal indicating the rotational speed (peripheral speed) of each of the four wheels.
2, 344, 346, 348, a brake switch 350 for detecting depression of the brake pedal 226, various detectors including a yaw rate sensor (not shown), and the pump motor 268, a pressure increasing electromagnetic control valve 290. To 296, and various actuators such as depressurizing electromagnetic control valves 298 to 304 are connected via drive circuits. The ROM of the computer stores a normal braking control routine, an antilock control routine, a traction control routine, a vehicle stability control routine, a vehicle running speed acquisition routine, and the like, including a main routine not shown and described.

At the time of braking, the master cylinder cut valve 24
4, 246 are closed and the pressure increasing electromagnetic control valves 290 to 29
The hydraulic pressure of the accumulator 270 is controlled to the target brake cylinder hydraulic pressure by the hydraulic pressure control valves 6 and the pressure reducing electromagnetic control valves 298 to 304 and supplied to the brake cylinders 210 to 216, thereby suppressing the rotation of the wheels. In the present embodiment, the target brake cylinder pressure is set based on the master cylinder pressure detected by the master cylinder pressure sensor 258. The antilock control, the traction control, and the vehicle stability control are performed by controlling the brake cylinder hydraulic pressure by the pressure increasing electromagnetic control valves 290 to 296 and the pressure reducing electromagnetic control valves 298 to 304. During these controls, the solenoid on-off valves 330, 3
32, 334 are closed.

In the vehicle of this embodiment, the traveling speed of the vehicle is obtained in the same manner as in the embodiment shown in FIGS. If there is a non-driving wheel, the traveling speed of the vehicle is obtained based on the peripheral speed of the non-driving wheel which is a lost wheel, if the lost wheel is only the driving wheel and the accelerator pedal is not depressed, The traveling speed of the vehicle is acquired based on the peripheral speed of the drive wheel that has failed. In the present embodiment, if the corresponding pressure-intensifying electromagnetic control valve fails and remains closed, for example, the hydraulic pressure is not supplied from the power hydraulic pressure source 222, and the hydraulic brake becomes an inoperative brake. The running speed of the vehicle can be obtained based on the peripheral speed of the failed wheel provided with the brake. The pressure-increasing electromagnetic control valves 290 to 296 are provided for each of the four hydraulic brakes, and some of the four wheels may fail, and the vehicle travels based on the peripheral speed of the failed wheel. Speed can be obtained. Alternatively, in the electronic control unit 340, the pressure increasing electromagnetic control valve 298
To control each of the control elements 304 to 304, for example, the solenoid 3
If one of the drive circuits controlling the supply current to 24 fails, some of the four wheels will fail.

In this embodiment, the pressure-increasing electromagnetic control valves 290 to 296 and the pressure-reducing electromagnetic control valves 298 to 304 constitute a hydraulic pressure control device, and constitute a brake control device together with the brake pedal 226 and the power hydraulic pressure source 222. are doing.

In the embodiment shown in FIGS. 10 and 11, the traveling speed of the vehicle may be obtained as in the embodiment shown in FIG. In that case, the traction control and the vehicle stability control may or may not be performed.

In the above embodiment, the brake cylinder is supplied with hydraulic pressure from a master cylinder or a pump to increase the brake cylinder hydraulic pressure. However, the brake cylinder hydraulic pressure is driven by an electric motor. The pressure may be increased by a pressurizing cylinder. An example is shown in FIG.

Although not shown, a brake having a brake cylinder is provided on each of the plurality of wheels, and the brake is operated by supplying hydraulic pressure to the brake cylinder to press a friction material against a rotating body to rotate the wheels. It is being suppressed. A pressure cylinder 370 and a pressure cylinder 37 are provided on the vehicle body side corresponding to each of the plurality of brake cylinders.
A driving device 372 for driving 0 is provided. By the housing 374 of the pressurizing cylinder 370, the rod 376 having a circular cross section is supported at two positions separated in the longitudinal direction so as to be liquid-tight and movable in the axial direction. In the middle of the rod 376, a flange portion extending outward in the radial direction is provided to constitute a piston 378, and thereby two liquid chambers 380 and 382 are formed in the housing 374.

The liquid chamber 380 on the downstream side in the forward direction (left direction in FIG. 12) of the rod 376 is connected to the port 38.
4 and a rubber hose (not shown), and is connected to a reservoir (not shown) at a port 386.
Is connected to the reservoir at port 388.
The piston 378 holds the cup seal 390 on the liquid chamber 380 side, and allows the flow of the hydraulic fluid from the liquid chamber 382 to the liquid chamber 380 side, but prevents the flow in the opposite direction. .

The driving device 372 has an electric motor 396 with a speed reducer as a driving source, and a motion conversion device 398 for converting the rotation of the electric motor 396 into a linear motion of the rod 376. The motion conversion device 398 has a male screw member 400 driven to rotate by an electric motor 396. The male screw member 400 is screwed to a female screw 402 provided through the rod 376 on the axis. The rod 376 has a fitting hole 4 extending in the axial direction at a position off the axis thereof.
06 is formed, and a rod-shaped member 408 erected on the casing 404 of the electric motor 396 is fitted so as to be relatively movable in the axial direction, and is prevented from rotating. The rod-shaped member 408 constitutes a rotation preventing member. When the male screw member 400 is rotated by the electric motor 396, the rod 376 is moved forward and backward. The male screw member 400 and the female screw 402 constitute the motion conversion device 398.

The rod 376 is advanced, and the piston 3
If the piston 78 is moved forward,
6 and the communication of the fluid chamber 380 with the reservoir is cut off, and then a fluid pressure is generated in the fluid chamber 380 and supplied to the brake cylinder, thereby suppressing the rotation of the wheels. Rod 37
When 6 is retracted, the hydraulic fluid in the brake cylinder returns to the fluid chamber 380, and the brake cylinder fluid pressure is reduced. At this time, hydraulic fluid is supplied from the liquid chamber 382 to the hydraulic chamber 380 through the cup seal 390, and the piston 378
Retreat is allowed.

As described above, the brake of this embodiment
It can be considered as a kind of hydraulic brake, and also as a kind of electric brake. The brake is, for example, an operation-impossible brake due to a failure of the electric motor 396, or an operation-command-impossible brake due to a failure of the control device that controls the electric motor 396. The electric motor 396 is provided for each of the plurality of wheels,
Some of the plurality of brakes may be inoperable brakes. For example, if a control device is provided for each of the plurality of brakes and constitutes a brake control device, some of the control devices may fail. Thereby, a part of the plurality of brakes becomes an operation command disabled brake. Alternatively, even if there is only one control device, if there is a portion that individually controls a plurality of brakes, a failure in that portion causes a portion of the plurality of brakes to become operation command disabled brakes. The traveling speed of the vehicle is acquired in the same manner as in each embodiment shown in FIG. 1 to FIG. 8 or FIG. 9, and if there is a failed wheel whose brake is an inoperative brake, based on the rotation speed of the failed wheel, The traveling speed of the vehicle can be accurately obtained without wasting the braking force.

In each of the above embodiments, when there is a wheel (failed wheel) whose brake is an inoperative brake, and when the running speed of the vehicle is obtained based on the peripheral speed of the wheel, the anti-lock control is performed. Although the target slip ratio is fixed, it may be variable. For example, the target slip ratio is changed according to the maximum coefficient of friction of the road surface. In the state where the anti-lock control is being performed, the deceleration of the vehicle and the maximum friction coefficient of the road surface correspond one to one, and the maximum friction coefficient is obtained from the deceleration. The slip rate at which the maximum friction coefficient is obtained differs depending on the magnitude of the maximum friction coefficient, and the target slip rate is set to the slip rate at which the maximum friction coefficient is obtained.

When the traveling speed of the vehicle is obtained, if the brakes are not operated or the brakes are not operated and all the lost wheels are drive wheels, the left and right peripheral speeds of the four wheels are used. The smaller of the average value of the peripheral speeds of the rear wheels and the average value of the peripheral speeds of the left and right front wheels may be used as the traveling speed of the vehicle. The average value of the peripheral speeds may be used as the traveling speed of the vehicle.

Further, the present invention relates to a vehicle other than a vehicle in which the front wheels are driving wheels and the rear wheels are non-driving wheels, for example, a vehicle in which the front wheels are non-driving wheels and the rear wheels are driving wheels, May be applied to vehicles in which the wheels are drive wheels.

Although some embodiments of the present invention have been described in detail above, these are merely examples, and the present invention is not limited to the above-mentioned [Problems to be Solved by the Invention, Means for Solving Problems and Effects]. The present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art, including the described embodiment.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an electric brake system for a vehicle according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a connection between a central control device, a motor control device, an input device, and a battery which constitute the electric brake system.

FIG. 3 is a graph showing characteristics of two stroke sensors and two pedaling force sensors constituting the input device.

FIG. 4 is a table showing a control mode when all the control devices are normal in the electric brake system and a control mode of a normal control device when one control device fails.

FIG. 5 is a chart showing a control mode of a normal control device when two control devices fail in the electric brake system.

FIG. 6 is a table showing control modes of normal control devices when three control devices fail in the electric brake system.

FIG. 7 shows a RO of a main microcomputer constituting the central control unit.
5 is a flowchart illustrating a vehicle traveling speed acquisition routine stored in M.

FIG. 8 is a block diagram showing a portion of the RAM of the main microcomputer that is deeply relevant to the present invention.

FIG. 9 is a diagram showing a RO of a main microcomputer of a central control device constituting an electric brake system of a vehicle according to another embodiment of the present invention;
5 is a flowchart illustrating a vehicle traveling speed acquisition routine stored in M.

FIG. 10 is a circuit diagram showing a hydraulic brake system for a vehicle according to still another embodiment of the present invention.

11 is a front view (partial cross section) showing a pressure-increasing electromagnetic control valve and a pressure-reducing electromagnetic control valve that constitute the hydraulic brake system shown in FIG. 10;

FIG. 12 is a front view showing a pressurizing cylinder for increasing and decreasing the hydraulic pressure of a brake cylinder of an electric brake system provided in a vehicle according to still another embodiment of the present invention, together with a driving device.

[Explanation of symbols]

10: Brake control device 12, 14, 16, 18:
Electric brakes 20, 22: Battery 24: Left front wheel 26: Right front wheel 28: Left rear wheel 30: Right rear wheel 32, 34, 36, 38: Motor 50: Central controller 52, 54, 56, 58: Motor controller 70: Brake pedal 200: Left front wheel 20
2: Right front wheel 204: Left rear wheel 206: Right rear wheel
226: Brake pedal 290,292,294,
296: Pressure increasing electromagnetic control valve 298, 300, 30
2,304: depressurizing electromagnetic control valve 340: electronic control unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fumiaki Kawabata 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Automobile Co., Ltd. (72) Naoki Sawada 1-1-1 Showa Town, Kariya City, Aichi Prefecture Inside DENSO Corporation (72) Inventor Masahiro Matsuura 1-1-1, Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (Reference) 3D046 BB01 BB28 EE01 HH23 HH36 HH42 KK01

Claims (3)

[Claims] A brake control for operating a plurality of brakes provided on each of a plurality of wheels and at least one of the plurality of brakes based on at least one of a brake operation by a driver and a traveling state of the vehicle. A device, an inoperative brake detecting device that detects one of the plurality of brakes that should be operated but does not operate, and a rotation speed of a wheel corresponding to the brake detected by the inoperative brake detecting device. A traveling speed acquisition device that acquires the traveling speed of the vehicle based on the vehicle speed. 2. The brake system according to claim 1, wherein the inoperative brake detection device includes an operation command disabled brake detection unit that detects a brake that cannot be operated due to a cause of the brake control device. The vehicle described. 3. The vehicle according to claim 2, wherein the plurality of wheels include a driving wheel driven by a driving device of the vehicle, and a non-driving wheel not driven by the driving device. When both the brake corresponding to the drive wheel and the brake corresponding to the non-drive wheel are detected as inoperative brakes, the traveling speed is acquired based on the rotation speed of the non-drive wheel. The vehicle according to claim 1, wherein the vehicle is a vehicle.