JPH0341970Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to an electromagnetic servo brake device that uses electromagnetic force to double the braking pressure applied to the brake members of each wheel of an automobile. Concerning measures to ensure assist power in the event of failure.

(Prior art) Conventionally, a brake device that generates braking pressure using electromagnetic force detects the impact force at the time of a vehicle collision, and detects the impact force at the time of a vehicle collision. A vehicle is known that automatically generates braking pressure using electromagnetic force regardless of whether or not a person operates the brake, thereby quickly stopping the vehicle.

(The problem that the invention is trying to solve) Therefore, based on this conventional thinking,
When the driver depresses the brake pedal, braking pressure is applied to the brake members of each wheel, for example, in order to double the braking pressure generated by the depressing operation by electromagnetic force. A master cylinder having a braking oil chamber, a braking pressure detection sensor that detects the braking pressure generated in the master cylinder, a pedal depression force detection sensor that detects the depression force applied to the brake pedal, and receiving outputs from both of the above sensors, an electromagnetic servo brake device including electromagnetic means for applying assist hydraulic pressure to the brake oil chamber of the master cylinder so as to maintain both outputs in a predetermined boosting relationship;
It is conceivable that when the brake pedal is depressed, a predetermined boost of assist hydraulic pressure is generated by electromagnetic means based on the brake pedal depression force, and this assist hydraulic pressure is applied to the brake oil chamber of the master cylinder to boost the braking pressure.

However, this concept is applied to, for example, a brake system that is equipped with a split-type master cylinder having multiple oil chambers, and in which the brake pipes from each oil chamber of the master cylinder to the brake members of each wheel are divided into multiple systems. In this case, if one of the hydraulic systems fails, when the brake pedal is depressed, the electromagnetic means is activated at the same time as the brake pedal force is generated, and boost-related assist hydraulic pressure is applied to each brake oil chamber of the master cylinder. , the operation of the electromagnetic means ends while the pressure oil in the oil chamber corresponding to the failed hydraulic system flows out, and the electromagnetic means then restores assist hydraulic pressure to the remaining oil chamber corresponding to the hydraulic system that has not failed. There is a possibility that good assisting force cannot be obtained.

This problem can be solved by setting the stroke of the plunger that generates hydraulic pressure in the electromagnetic means to be equal to the stroke of the master cylinder, but such a large stroke electromagnetic means is disadvantageous in terms of weight and cost. .

This invention was made in consideration of these points,
The purpose of this is to start the operation of the electromagnetic means only when the braking pressure generated in the master cylinder becomes higher than a predetermined value when the brake pedal is depressed, thereby creating a compact design with a short operating stroke. It is an object of the present invention to enable electromagnetic means to ensure a good assisting force even when a hydraulic system fails.

(Means for solving the problem) In order to achieve the above object, the solution means of the present invention, as described above, includes a pedal depression force detection sensor that detects the brake pedal depression force, a master cylinder, and a brake member of each wheel. A braking pressure detection sensor that is installed in the middle of the connected brake pipes and detects the braking pressure from the master cylinder;
In an electromagnetic servo braking device for an automobile, the electromagnetic means is driven in response to the outputs of the pedal force detection sensor and the braking pressure detection sensor, and the electromagnetic means maintains both outputs in a predetermined boosting relationship. a comparison means for comparing the brake pressure with a predetermined reference signal; and a comparison means that receives the output from the comparison means and operates the electromagnetic means when the output signal of any one of the plurality of braking pressure detection sensors becomes higher than the reference signal. A switch member for energizing is provided.

(Function) With the above configuration, in the present invention, even if one of the plurality of hydraulic systems between the master cylinder and the cylinder member of each wheel fails, the braking pressure in the hydraulic system without failure remains at a predetermined level. When the brake pressure rises higher than a reference value, the electromagnetic means is operated to assist the braking pressure with the assist hydraulic pressure,
This system uses compact electromagnetic means to ensure good assisting force in the event of a hydraulic system failure.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In FIG. 1, 1 is a brake pedal, and 2 is a master cylinder that generates braking pressure by depressing the brake pedal 1. The master cylinder 2 is slidably inserted in series in a cylinder body 3. primary and secondary pistons 4, 5
and 1 defined by the pistons 4 and 5.
It is equipped with next and secondary oil chambers 6, 7 and return springs 8, 9 compressed in the oil chambers 6, 7, respectively, and the upper parts of both the oil chambers 6, 7 are formed in the cylinder body 3. The lower part of the primary oil chamber 6 is connected to the reserve tank 10 via the relief ports 3a and 3b, and the lower part of the primary oil chamber 6 is connected to each brake member (not shown) of the front wheel (front wheel) via a hydraulic passage in the brake pipe 11. ), the lower part of the secondary oil chamber 7 is also communicated with, for example, each brake member (not shown) of the rear wheel (rear wheel) via a hydraulic passage within the brake pipe 12. Further, the primary piston 4 is linked to the brake pedal 1 via a push rod 13, and when the brake pedal 1 is depressed, the push rod 1
3, the primary and secondary pistons 4, 5 are advanced to the left in the figure to close both relief ports 3a, 3b, and braking pressure is generated in the primary and secondary oil chambers 6, 7. This braking pressure is applied to brake pipe 1
1 and 12, the vehicle is braked by acting on the brake members of each wheel.

Also, behind the primary piston 4 (to the right in the figure)
A brake oil chamber 15 is formed by the rear wall of the primary piston 4 and a partition member 14 fixed to the cylinder body 3, and when the brake pedal 1 is depressed, an electromagnetic means (described later) is inserted into the brake oil chamber 15. By supplying pressure oil through 19, the rear surface of the primary piston 4 is pushed forward together with the push rod 13,
The braking pressure applied to each wheel's brake member is doubled.

A pedal force detection sensor 16 is disposed around the push rod 13 and is comprised of a load sensor that detects the force applied to the brake pedal 1 when the brake pedal 1 is depressed. Further, in the middle of the brake pipe 11 of the front wheel system that connects the master cylinder 2 and the brake member of the front wheel, there is a first pipe for detecting the braking pressure acting on the front wheel brake member from the primary oil chamber 6 of the master cylinder 2. The braking pressure detection sensor 17 is located in the secondary oil chamber 7 of the master cylinder 2 in the middle of the brake pipe 12 of the rear wheel system that connects the master cylinder 2 and the rear wheel side brake member.
A second braking pressure detection sensor 18 is provided for detecting the braking pressure acting on the rear wheel brake member from the rear wheel.

Further, 19 is an electromagnetic means which receives the outputs of the pedal depression force detection sensor 16 and both braking pressure detection sensors 17 and 18 and is driven by the controller 28 so as to maintain the two outputs in a predetermined boosting relationship,
The electromagnetic means 19 includes an electromagnet 20 having a coil 20a that is excited in response to an output signal from a controller 28, a plunger 21 that is attracted by the electromagnet 20 and advances leftward in the figure, and a central portion of the plunger 21. A rod 22 inserted and fixed in the front-rear direction, a piston 24 that is pressed by the rod 22 and slides inside the cylinder body 23, an oil chamber 25 defined by the piston 24, and the oil chamber 25. The oil chamber 25 is connected to the brake oil chamber 15 of the master cylinder 2 via an oil supply passage 27, and the electromagnet When the output signal of the controller 28 is input to the plunger 20, the plunger 2 is actuated with a suction force according to the output signal.
1 and moves the piston 24 forward, a predetermined boost of assist oil pressure is generated in the oil chamber 25, and this oil pressure is applied to the brake oil chamber 15 of the master cylinder 2 via the oil supply passage 27. That's what I do.

Further, the internal configuration of the controller 28 which controls the operation of the electromagnetic means 19 in response to the outputs of the pedal force detection sensor 16 and the braking pressure detection sensors 17 and 18 will be described in detail with reference to FIG. The controller 2
8 is the output signal Qi of the pedal force detection sensor 16
The output signals of the non-inverting amplifiers 30 and 31 are compared with the inverting amplifier 29 which inverts and amplifies the output signals P _MC1 and P _MC2 of the braking pressure detection sensors 17 and 18, respectively, and the non-inverting amplifiers 30 and 31 which non-invert amplifies the output signals P MC1 and P MC2 of the braking pressure detection sensors 17 and 18, respectively. a signal switching circuit 40 that switches to the higher output signal;
A deviation amplifier 32 amplifies the deviation signal between the output signal from the signal switching circuit 40 and the output signal of the inverting amplifier 29; In comparison, a first comparator 34 outputs a Hi level signal when the output signal of the deviation amplifier 32 is higher than the triangular wave signal;
A first transistor 35 is turned ON to energize the electromagnet 20 of the electromagnetic means 19 upon receiving a Hi output signal from the electromagnetic means 19. In response to the deviation signal, the first comparator 34
By changing the duty ratio of the Hi level signal and controlling the ON duty time of the first transistor 35, that is, the time during which the electromagnetic means 19 is energized, the braking pressure detected by each braking pressure detection sensor 17, 18 can be adjusted. It is configured to maintain a boosting relationship with respect to the pedal depression force.

Furthermore, the controller 28 receives output signals P _MC1 and P _MC2 of the braking pressure detection sensors 17 and 18.
A second comparator 3 as comparison means compares the output signal with a predetermined reference voltage signal Vref and outputs a Hi level signal when the output signals of the two braking pressure detection sensors 17 and 18 are both lower than the reference voltage signal Vref.
6 and the output of the comparator 36 is turned ON.
A second transistor 37 that operates OFF is provided, and the second transistor 37 is connected to the comparator 3.
When a Hi-level signal is output from 6 (when the output signals of braking pressure detection sensors 17 and 18 are both lower than the reference voltage signal Vref), it is activated and shorts the output of the first comparator 34 to ground. However, when the output of the second comparator 36 becomes Lo level, that is, when the braking pressure detection sensor 17, 18
One of the output signals is the reference voltage signal.
When it becomes higher than Vref, it is turned OFF and the output of the first comparator 34 is changed to the electromagnetic means 19.
The electromagnet 20 is energized to operate the electromagnetic means 19.

Next, to explain the operation of the above embodiment,
In a normal state where neither the front wheel system nor the rear wheel system has malfunctioned in the hydraulic system, when the brake pedal 1 is depressed, the primary and secondary pistons 4, 4 of the master cylinder 2,
5 advances to the left in FIG. 1 to increase the oil pressure in the primary and secondary oil chambers 6 and 7, and this increased oil pressure in the oil chambers 6 and 7 is applied to the front and rear wheel brake pipes 11, respectively. , 12 to actuate the brake members on the front and rear wheels, and the operation of the brake members suppresses the rotation of the front and rear wheels, thereby braking the vehicle. is started.

At that time, the pedal force detection sensor 16 detects the pedal force applied to the brake pedal 1, and the hydraulic pressure in each brake pipe 11, 12, that is, the braking pressure acting on each wheel from the oil chambers 6, 7 of the master cylinder 2, is detected. The output signals P _MC1 and P _MC2 from the braking pressure detection sensors 17 and 18 are respectively detected by the braking pressure detection sensors 17 and 18, and are compared with the reference voltage signal Vref in the second comparator 36 of the controller 28. Then, at the point when the brake pedal 1 is depressed and the operation begins,
When the output signals from the braking pressure detection sensors 17 and 18 are compared and the output signal output from the signal switching circuit 40 is lower than the reference voltage signal Vref,
A Hi level signal is output from the second comparator 36 and the second transistor 37 (switch member) is activated.
When the transistor 37 is turned ON, the output signal of the first comparator 34 flows to the ground, and the first transistor 35 is kept in the OFF state. As a result, the electromagnet 20 of the electromagnetic means 19 is not energized, so that the electromagnetic means 19 is kept inactive, and the braking pressure is not boosted by the electromagnetic means 19.

Thereafter, when the pedaling force applied to the flake pedal 1 increases and the output signals of the braking pressure detection sensors 17 and 18 are compared, and the output signal output from the signal switching circuit becomes higher than the reference voltage signal Vref, the second The output of the Hi level signal from the coparator 36 is stopped, and the second transistor 37 is turned off.
Due to this OFF operation of the second transistor 37, the duty signal that becomes Hi level when the output signal of the first comparator 34, that is, the output signal of the deviation amplifier is higher than the triangular wave signal from the triangular wave generator 33, is directly transferred to the first transistor 35. is output, and the transistor 35 operates at a predetermined duty ratio.
ON operates. While this transistor 35 is ON, the electromagnetic means 19 is energized and operates.
The piston 24 pressurizes the inside of the oil chamber 25 and applies the oil pressure to the brake oil chamber 15 of the master cylinder 2, and the assist oil pressure from the electromagnetic means 19 acts on each brake member on the front and rear wheels. The applied braking pressure is multiplied by the brake pedal force, and the braking force of the vehicle is assisted.

On the other hand, in the event of an abnormality in which, for example, the front wheel side hydraulic system has failed among the above two hydraulic systems, when the brake pedal 1 is depressed, the master cylinder 2 corresponding to the failed hydraulic system will first be activated. 1
The secondary piston 4 advances and the pressure oil in the primary hydraulic pressure 6 flows out. After this, when the return spring 8 is contracted and the primary piston 4 is integrally linked with the secondary piston 5, the secondary piston 5 also moves forward, and the second piston 4 corresponding to the hydraulic system that has not failed is moved forward. The oil pressure in the next oil chamber 7 begins to rise, and thereafter, the same operation as in the normal state is performed. That is, when the output signal P _MC2 of the braking pressure detection sensor 18 is lower than the reference voltage signal Vref, the second transistor 37 is turned on.
When the electromagnetic means 19 is activated and the output signal of the braking pressure detection sensor 18 becomes higher than the reference voltage signal Vref, the second transistor 37 is activated.
The electromagnetic means 19 is controlled to operate by turning OFF.

Therefore, in this embodiment, when one of the front wheel side or rear wheel side hydraulic systems fails, the braking pressure of the other hydraulic system increases above the reference pressure set by the reference voltage signal Vref. Since the electromagnetic means 19 operates and the braking pressure from the master cylinder 2 is boosted, the braking force can be reliably assisted by the electromagnetic means 19 even when the hydraulic system fails.

In that case, the electromagnetic means 1 must be
Since the operation of the electromagnetic means 9 is stopped, a compact electromagnetic means 19 having a short operating stroke length can be used as the electromagnetic means 19 for boosting the braking pressure, and the weight and cost of the electromagnetic means 19 can be reduced.

In addition, in the above embodiment, the braking pressure detection sensor 17,
18 and the reference voltage signal Vref, the signal switching circuit 40 compares the output signals output from the braking pressure detection sensors 17 and 18 respectively, switches the higher one and outputs it. I tried to compare the signal with the reference voltage signal Vref, but
As shown in FIG. 3, a plurality of brake pipes 1
1 and 12 are connected by an oil pressure switching valve 41, and a braking pressure detection sensor 42 (the higher oil pressure of the brake pipes 11 and 12 is detected) is connected to this switching valve 41.
from the braking pressure detection sensor 42 to the amplifier 4.
Output signal and reference voltage signal output through step 3
It is also possible to compare it with Vref.

(Effects of the invention) As explained above, according to the invention, when any of the braking pressures in the plurality of hydraulic systems connecting the master cylinder and the brake members of each wheel becomes higher than a predetermined reference value. Since the braking pressure is sometimes doubled by operating an electromagnetic means, even a compact electromagnetic means with a short operating stroke can ensure a good assisting force by the electromagnetic means in the event of a failure of the hydraulic system. This can contribute to improving the reliability of electromagnetic servo brake devices for automobiles.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is an overall configuration diagram, FIG. 2 is a control circuit diagram for controlling the operation of the electromagnetic means, and FIG. 3 is a diagram equivalent to FIG. 2 showing a modification. DESCRIPTION OF SYMBOLS 1... Brake pedal, 2... Master cylinder, 11, 12... Brake pipe, 16... Pedal force detection sensor, 17, 18... Control pressure detection sensor, 19... Electromagnetic means, 28... Controller, 36 ...Second comparator, 37...Second transistor.

Claims (1)

[Scope of utility model registration request] A pedal force detection sensor that detects the force applied to the brake pedal, and a braking pressure detection sensor that detects the braking pressure from the master cylinder, which is installed in the middle of multiple brake pipes that connect the master cylinder and the brake members of each wheel. an electromagnetic means that is driven in response to the output of the pedal force detection sensor and the output of the braking pressure detection sensor and maintains both outputs in a predetermined boosting relationship; a comparison means for comparison, and a switch member that receives the output from the comparison means and activates the electromagnetic means when an output signal of any one of the plurality of braking pressure detection sensors becomes higher than a reference signal. An electromagnetic servo brake device for an automobile, comprising: