JPH069963B2 - Electromagnetic servo brake device for automobile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an electromagnetic servo for an automobile, which assists the depression force of a brake pedal to boost the braking pressure of a brake master cylinder during braking of the automobile. The present invention relates to a brake device.

[Prior Art] Conventionally, a braking device that generates a braking force by an electromagnetic force is known, and is disclosed in JP-A-49-1612.
Japanese Patent Laid-Open No. 8 discloses that the impact force at the time of a vehicle collision is detected and the vehicle is stopped by automatically generating a braking force by an electromagnetic force regardless of whether or not a driver operates a brake during the vehicle collision. Things are disclosed.

By the way, generally, a brake device of an automobile employs a structure in which a pedaling force of a brake pedal is converted into a hydraulic pressure by a master cylinder and the braking hydraulic pressure is applied to a braking member provided for a wheel. However, if a desired high braking hydraulic pressure is to be obtained only by the depression force of the brake pedal, the depression of the brake pedal becomes heavy and the brake operability deteriorates. Under such circumstances, there has been proposed a vacuum drive type brake device that assists the brake pedal force and boosts the obtained braking force, and is an electric vehicle that does not have a vacuum source like an automobile equipped with an internal combustion engine. In automobiles and the like, it is possible to use electromagnetic force as an assist force for the brake pedal force.

However, when the brake device is equipped with an electromagnetic booster that uses electromagnetic force as an assist force, the vehicle is in an electrically severe environment such as noise generation,
It is necessary to give sufficient consideration to the safety of the control system of the electromagnetic booster.

[Object of the Invention] An object of the present invention is to increase the safety of a brake device of a vehicle equipped with an electromagnetic booster that uses an electromagnetic force as an assist force for a brake pedal force, even if the brake pedal is not depressed. Regardless, when sudden braking is applied, this sudden braking is promptly released to improve safety.

Therefore, according to the present invention, the pedal depression force detection sensor that detects the brake depression force and the electromagnetic means that maintains the output of the braking pressure detection sensor that detects the braking pressure of the mass cylinder in a predetermined boosting relationship are provided. With the detection output of these two detection sensors as input,
An abnormal signal output section that generates an abnormal signal when there is an output from the braking pressure detection sensor even when the pedal effort is zero, that is, the brake pedal is not depressed, and an electromagnetic signal when an abnormal signal is generated. The drive circuit of the means is provided with a shutoff means for shutting off automatically or manually.

[Effects of the Invention] According to the present invention, even when sudden braking is applied against the driver's will, the rapid braking can be quickly released.
It is possible to improve the safety of the electromagnetic servo brake device of this type of vehicle.

Further, according to the present invention, the pedal depression force detection sensor and the braking pressure detection sensor, which are originally necessary for controlling the operation of the electromagnetic means, are used to detect the malfunction of the electromagnetic means, so that a special abnormality detection sensor is provided. There is no need, the configuration can be simplified and the cost can be reduced.

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 2, the master cylinder 2 that generates a braking pressure in response to the depression of the brake pedal 1 has a primary piston 5 that interlocks with the brake pedal 1 via a push rod 4 in a cylinder body 3. A primary oil chamber 6 is held between the both sides in the axial direction by two springs, and a secondary piston 8 forming a secondary oil chamber 7 on the opposite side of the primary piston 5 is provided. And basically, when the primary piston 5 is displaced to the left in FIG. 2,
Following this, the secondary piston 8 is displaced to the left, and the relief port 3 communicating with the reserve tank 9 as shown in the figure.
By closing a and 3b, braking pressure is generated in the primary and secondary oil chambers 6 and 7. The braking pressure generated in this way is applied to the brake members of the wheels (not shown) via the brake pipes 10A and 10B, respectively, and the vehicle is braked.

The rear side of the primary piston 5 of the master cylinder 2 (second
A braking oil chamber 11 is formed by a partition wall member 12 on the right side of the drawing. The braking oil chamber 11 is in communication with a boosting hydraulic pressure chamber 15 formed in the electromagnetic means 14 via a communication passage 13. The electromagnetic means 14 is a plunger 18 that is attracted by an electromagnetic solenoid 17 that generates an electromagnetic attraction force according to the braking output from the controller 16.
And a piston 20 that interlocks with the suction of the plunger 18 via a push rod 19. Further, the controller 16 that controls the electromagnetic means 14 detects the pedaling force detection sensor 21 that detects the pedaling force of the brake pedal 1 and the braking hydraulic pressure actually generated by the master cylinder 2 from the hydraulic pressures of the brake pipes 10A and 10B. The output signals of the braking pressure detection sensors 22 and 23 are input, and basically, the output to the electromagnetic solenoid 17 is controlled so that the pedal effort and the braking hydraulic pressure change while maintaining a predetermined boosting relationship. In other words, the hydraulic pressure generated in the hydraulic pressure generation chamber 15 by the piston 20 of the electromagnetic means 14, that is, the hydraulic pressure in the braking oil chamber 11 is increased in proportion to the pedal depression force detected by the pedal depression force detection sensor 21. The primary piston 5 is stroked by receiving both the pedaling force and the hydraulic pressure of the braking oil chamber 11, and the primary and secondary oil chambers 6 and 7 are boosted by a pedaling force that cannot be obtained only by the pedaling force. The generated high braking hydraulic pressure is generated.

As shown in FIG. 1, the electromagnetic solenoid 17 includes a switching transistor T built in the controller 16.
The amount of current is controlled by turning on and off r, and the braking output to the switching transistor Tr is controlled so as to maintain the pedal effort and the braking hydraulic pressure in a predetermined boosting relationship.

According to the present invention, when the electromagnetic means 14 is operated despite the fact that the drive circuit malfunctions for some reason and the brake pedal 1 is not depressed with respect to the basic drive circuit of the electromagnetic servo brake device for an automobile described above. Further, a cutoff circuit 24 that cuts off the power supply to the electromagnetic solenoid 17 is provided.

The cutoff circuit 24 inputs a pedal depression force signal detected by the depression force detection sensor 21 and a braking pressure signal detected by the braking pressure sensors 22 and 23 (only one of which is shown in FIG. 1). An abnormality detection circuit 25
A cutoff command changeover switch 26 provided on the output side of the abnormality detection circuit 25, a cutoff switch 27 that is interlocked with the cutoff command changeover switch 26, and is connected between the electromagnetic solenoid 17 and the switching transistor Tr. A disconnection command relay 28 connected between a common contact of the disconnection command changeover switch 26 and the ground, and normally open first and second relay contacts that are turned on when the disconnection command relay 28 is excited. 29 and 30 are provided.

The abnormality detection circuit 25 applies the brake pressure signal, that is, when the brake pressure signal is input when the brake pedal 1 is not pressed, that is, the brake is applied against the driver's will. Sometimes, this is detected and an abnormality detection signal is output. When this abnormality detection signal is output, the breaking command relay 28 is excited through the breaking command changeover switch 26. When the relay 28 is excited, the first and second relay contacts 29 and 30 are simultaneously turned on, and the alarm lamp 31 is turned on to alert the driver of the abnormality of the electromagnetic servo brake, while the stop switch 32 is usually provided. Stop lamp 33 of the car, which is turned on and off via
34 is compulsorily lit to inform the following vehicle that braking is in progress.

When the brake lamp malfunctions due to the lighting of the alarm lamp 31 and the brake is applied even though the brake pedal is not actually stepped on, the driving vehicle switches the cutoff command changeover switch 26 from ON to OFF. . By this switching, the cutoff switch 27 is also switched from ON to OFF, and as a result, the electromagnetic solenoid 17 and the switching transistor Tr are completely separated from each other, and the power supply to the electromagnetic solenoid 17 is cut off. The demagnetization 17 deactivates the electromagnetic means 14, and the braking hydraulic pressure generated in the master cylinder 2 is released. Then, the disconnection command relay 28 is demagnetized, and the alarm lamp 31, the stop lamps 33, 34 are turned off.

In FIG. 1, B is a battery, IgSW is an ignition switch, and D is an electromagnetic solenoid protection diode.

In the above-described configuration of the shutoff circuit 24, the shutoff switch 27 is turned off by the driver's operation, but when an abnormality is detected, the energization of the electromagnetic solenoid 17 may be automatically shut off.

As shown in FIG. 3, in that case, the disconnection command relay 35 is connected to the output side of the abnormality detection circuit 25, and
An electromagnetic solenoid disconnection relay contact 36 is connected between the electromagnetic solenoid 17 and the switching transistor Tr,
A relay contact 37 for turning on the alarm lamp 31 may be provided.

The electromagnetic solenoid cutoff relay contact 36 is a relay contact that is normally on and is turned off when the cutoff command relay 35 is excited, and the alarm lamp lighting relay contact 37 is always off and the cutoff command relay. A relay contact that is turned on when 35 is excited is used.

In this embodiment, therefore, the abnormality detection circuit 25 detects the malfunction of the electromagnetic means 14, detects that the braking hydraulic pressure is generated even though the brake pedal 1 is not depressed, and outputs the abnormality detection signal. Then, the electromagnetic solenoid 1 is automatically
The drive circuit of 7 is cut off, the alarm lamp 31 lights up,
It warns of any abnormality in the drive circuit.

The cause of the above abnormality may be a failure of the switching transistor Tr, a short circuit of the electromagnetic solenoid 17 to the ground, a failure of the amplifier of the controller 16 or the like. The resulting anomaly can be accurately detected without the need to detect.

Further, in the above embodiment, the operation of the electromagnetic means is detected by the outputs of the braking pressure sensors 22 and 23, but the present invention is not limited to this, and the presence or absence of energization of the electromagnetic solenoid 17 is detected. In short, a sensor that detects the presence or absence of the operation of the electromagnetic means, such as a sensor that operates, may be used.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of an electromagnetic servo brake device showing an embodiment of the present invention, FIG. 2 is a sectional view showing a basic structure of the electromagnetic servo brake, and FIG. 3 is a diagram showing another embodiment of the present invention. It is a control circuit diagram similar to FIG. DESCRIPTION OF SYMBOLS 1 ... Brake pedal, 2 ... Master cylinder, 14 ... Electromagnetic means, 21 ... Treading force detection sensor, 22, 23 ... Braking pressure detection sensor, 24 ... Breaking circuit, 25 ... Abnormality detection circuit.

Claims (3)

[Claims] Claims: 1. A pedal depression force detection sensor for detecting an increase in the depression force applied to the brake pedal, a braking pressure detection sensor for detecting an increase in the braking pressure of the master cylinder, and an output of the pedal depression force detection sensor and the braking pressure detection sensor. When the pedaling force is zero and there is a braking pressure detection sensor output, the electromagnetic means that keeps both outputs in a predetermined boosting relationship is compared with the output from the pedal depression force detection sensor and the output from the braking pressure detection sensor. An electromagnetic servo for an automobile, comprising: an abnormal signal output section for outputting an abnormal signal; and a breaking means for breaking the drive circuit of the electromagnetic means when the abnormal signal is outputted from the abnormal signal output section. Brake device. 2. The electromagnetic servo brake device for an automobile according to claim 1, wherein the breaking means is a breaking circuit which automatically cuts off a drive circuit of the electromagnetic means upon receipt of an abnormal signal. 3. The electromagnetic servo brake device for an automobile according to claim 1, wherein the breaking means is a manual switch operated by a driver when an abnormal signal is received.