JP3253039B2 - Vehicle braking system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transmitting brake hydraulic pressure stored in an accumulator to a wheel brake via a first opening / closing valve, and transmitting brake hydraulic pressure transmitted to the wheel brake to a reservoir via a second opening / closing valve. The present invention relates to a vehicle braking device that causes a wheel brake to exert a braking force according to the depression force of a brake pedal by being released to a vehicle.

[0002]

2. Description of the Related Art Such a vehicle braking device is disclosed in Japanese Patent Application Laid-Open No. Hei 3-1.
It is already known as described in the first embodiment of 36962.

[0003]

In the above-described conventional vehicle braking device, when the internal pressure of the accumulator is reduced by operating the wheel brake, the pressure switch is operated to drive the hydraulic pump, and the discharge pressure is used. The accumulator is again charged. However, when the internal pressure of the accumulator drops below a predetermined value due to a failure of the pressure switch, the hydraulic pump, or the accumulator itself, or when the control unit fails, there is a possibility that the wheel brake becomes difficult to exert sufficient braking force. is there.

The present invention has been made in view of the above circumstances, and has as its object to provide a vehicular braking device capable of exerting a sufficient braking force on a wheel brake when an accumulator or control means fails. And

[0005]

In order to achieve the above object, an invention according to claim 1 comprises an accumulator for accumulating brake oil pressure, a wheel brake for braking a wheel, and an intervening device between the accumulator and the wheel brake. A first on-off valve mounted on the vehicle, a second on-off valve interposed between the wheel brake and the reservoir, a treading force detecting means for detecting a treading force of a brake pedal, and a first,
A control device for controlling the opening / closing of a second opening / closing valve, wherein a normally-open type which is connected to the control device and controlled to open / close between a master cylinder operated by a brake pedal and a wheel brake. A third opening / closing valve is interposed, and the third opening / closing valve is opened to the master cylinder.
Operate by operating the brake pedal at the time of valve
Blockage that interrupts communication between the second on-off valve and the reservoir
Means are provided .

[0006]

[0007]

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

FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of a vehicular braking device, and FIG. 2 is a longitudinal sectional view of a master cylinder.

As shown in FIG. 1, driven by a motor 1
Provided on the discharge port of the hydraulic pump 2 and the wheels W
The brake caliper Bc is the check valve 3 and the solenoid
Normally-closed first open / close valve V composed of a solenoid valve₁Directly
They are connected via a main oil passage Lm interposed in the row. May
Check valve 3 and first opening / closing valve V of the oil passage Lm ₁
An accumulator A that accumulates brake hydraulic pressure is
Continued. Accumulator A has cylinder 4 and cylinder
4, a piston 5 slidably fitted to the cylinder 4, a cylinder 4 and
A pressure accumulating chamber 6 defined by a piston 5;
A spring that urges the piston 5 in a direction to reduce the volume
7.

[0010] Brake caliper Bc and brake pedal 8
The return port 9 of the master cylinder Mc connected to the
Normally-closed second on-off valve V ₂ consisting of a solenoid valve
Are connected via a return oil passage Lr. A connection between the second opening / closing valve V ₂ and the return port 9 of the return oil passage Lr is connected to a suction port of the hydraulic pump 2 via a check valve 10.

[0011] The sub oil passage Ls connecting the output port 11 of the master cylinder Mc and the brake caliper Bc, third on-off valve V ₃ normally open consisting of the solenoid valve is interposed. Third on-off Bal V ₃ is communicated with the master cylinder Mc and the brake caliper Bc when in the open state,
Third on-off Bal V ₃ is communicated with the master cylinder Mc and the brake caliper Bc when in the closed state is shut off.

An electronic control unit U composed of a microcomputer includes a brake pedal switch 21 for detecting operation of the brake pedal 8, a load cell 22 for detecting the depression force of the brake pedal 8, and a wheel speed sensor 23 provided for the wheel W. Is connected. The brake pedal switch 21 can be replaced by a stop lamp switch. The electronic control unit U includes the brake pedal switch 21, the load cell 22, and the wheel speed sensor 23.
Are processed based on a predetermined program to open and close the first opening / closing valve V ₁ , the second opening / closing valve V _2, and the third opening / closing valve V ₃ . The accumulator A is provided with a limit switch 24 that is turned on when the accumulated pressure decreases below a predetermined value. When the amount of accumulated pressure in the accumulator A decreases and the limit switch 24 is turned on, the relay 25 operates and the motor 1 connected to the hydraulic pump 2
Is driven to increase the accumulated pressure amount of the accumulator A.

Next, the master cylinder Mc will be described with reference to FIG.
The structure of will be described.

[0014] The master cylinder Mc is through a cylinder body 31 having a cylinder bore 31 ₁ of which one end is opened, a guide member 33 fixed with a clip 32 fitted to the open end of the cylinder body 31, a guide member 33 and includes a piston 34 slidably fitted in the cylinder bore 31 _1, and a reservoir 35 that is supported by the reservoir communicating portion 31 ₂ formed on an upper portion of the cylinder body 31. The piston 34 is urged rearward by the spring 36 returns the compressed state between the front wall of the cylinder bore 31 _1, the rear end the piston 34
Stopper 34 ₁ formed in the rear of is restricted by abutting the front face of the guide member 33.

A seal 37 fitted to the front of the piston 34
And between the cylinder bore 31 ₁ of the front wall and the front oil chamber 38 is defined, the output port 11 to the front oil chamber 38
Opens. When the piston 34 is at the illustrated inoperative position, the front side of the seal 37 communicates with the reservoir 35 via the relief port 39, and the rear side of the seal 37 communicates with the reservoir 35 via the supply port 40.

A rear oil chamber 43 is defined between a pair of seals 41 and 42 fitted to the center and rear of the piston 34, and the return port 9 is opened in the rear oil chamber 43. When the piston 34 is in the inoperative position shown,
With the front of the seal 42 communicates with the oil passage 31 ₃ leading to the reservoir 35 through the relief port 44, the oil passage behind the seal 42 through the supply port 45 31
Communicate with ₃ . The seal 42 and the relief port 44
Constitutes the closing means of the present invention.

When the piston 34 is driven forward by the push rod 46 connected to the brake pedal 8, the seal 37 immediately passes through the relief port 39,
A brake oil pressure is generated in the front oil chamber 38. On the other hand, the distance between the seal 42 and the relief port 44 is set relatively large, so that the seal 42 does not close the relief port 44 even if the piston 34 advances within the normal stroke range, and the return port 9 Communicates with the reservoir 35 via the rear oil chamber 43 and the relief port 44. When the piston 34 advances beyond the normal stroke when the accumulator A fails, the seal 42 closes the relief port 44 and returns the return port 9 to the reservoir 35.
Communication with is interrupted.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

The driver Then ON the brake pedal switch 21 is stepped on the brake pedal 8, third on-off valve V ₃ normally open is closed by a command from the electronic control unit U, and the output port 11 of the master cylinder Mc The sub oil passage Ls connecting to the brake caliper Bc is closed.
At the same time, the electronic control unit U, which has received a signal from the load cell 22 for detecting the depression force of the brake pedal 8,
In order to generate a braking force corresponding to the pedal effort of the brake pedal 8 to the brake caliper Bc, it opens the first on-off valve V ₁ of the normally closed. As a result, the brake oil pressure accumulated in the accumulator A is transmitted to the brake caliper Bc via the main oil passage Lm, and brakes the wheels W with a predetermined braking force.

During the above-described braking, the wheel speed sensor 23
Signal indicates that the wheel W is prone to locking.
Then, the electronic control unit U opens the first opening of the main oil passage Lm.
Closed valve V₁And return valve Lr
2 open / close valve V_TwoIs opened. As a result, the brake key
The brake oil pressure acting on the caliper Bc is
Luv V_Two, Return port 9 of master cylinder Mc, rear oil
To the reservoir 35 via the chamber 43 and the relief port 44
The braking force of the wheel W is released by the brake caliper Bc
Decrease. In this way, the locking tendency is eliminated.
Then, the first opening / closing valve V of the main oil passage Lm again₁Open
And the second opening / closing valve V of the return oil passage Lr._TwoTo
The valve is closed and the braking force of the wheel W by the brake caliper Bc is reduced.
increase. Thus, according to the transition of the locking tendency of the wheel W,
And the first and second opening / closing valves V₁, V _TwoCan be opened and closed alternately
With this, the braking force generated by the brake caliper Bc is adjusted.
The locking of the wheel W can be prevented.

If the accelerator pedal is depressed too much or the vehicle is riding on a road with a low friction coefficient when the brake pedal 8 is not operated, a signal from the wheel speed sensor 23 causes an excessive slip on the wheel W. Is detected, the electronic control unit U closes the third on-off valve V ₃ and alternately opens and closes the first and second on-off valves V ₁ and V _2, thereby accumulating pressure in the accumulator A. The brake hydraulic pressure is transmitted to the brake caliper Bc to brake the wheel W, thereby suppressing excessive slip of the wheel W.

When the accumulated pressure of the accumulator A is reduced beyond a predetermined value by operating the brake caliper Bc, the limit switch 24 is operated to drive the motor 1 as described above, and the hydraulic pump 2 is connected to the reservoir 35. The accumulator A is accumulated with the discharged oil sucked through the return port 9 from the accumulator A.

When the brake hydraulic pressure stored in the accumulator A is lost due to the failure of the motor 1, the hydraulic pump 2, the limit switch 24 or the accumulator A itself, or when the electronic control unit U fails.
Via the third on-off valve V ₃ from the master cylinder Mc of the front oil chamber 38 hydraulic braking pressure output port 11 that occur normally open by depressing the brake pedal 8 is transmitted brake caliper Bc, thereby requiring an emergency Braking force is secured.

[0024] Incidentally, when the second on-off valve V ₂ interposed in the return oil path Lr when the fail is stick in the open state, the brake hydraulic pressure generated in the master cylinder Mc via the second on-off valve V ₂ The brake caliper Bc escapes to the reservoir 35 and cannot be operated. However, when the piston 34 advances in FIG. 2, the communication between the return oil passage Lr and the reservoir 35 is cut off by closing the relief port 44 by the seal 42, so that the brake caliper Bc can be operated without any trouble.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made.

For example, when braking a plurality of wheels W individually, the first and second opening / closing valves V ₁ and V ₂ are provided for each wheel W.
The provided, it is possible to share the hydraulic pump 2, an accumulator A and the third on-off valve V _3.

[0027]

As described above, according to the present invention, even if the brake hydraulic pressure stored in the accumulator is lost or the control means fails, the brake generated by the master cylinder connected to the brake pedal is generated. The hydraulic pressure is transmitted to the wheel brakes via the normally open third opening / closing valve, so that the necessary braking force can be secured.

[0028] The second opening and closing valve when the fail of or accumulator or control means to stick in the open state,
Since the communication between the wheel brake and the reservoir is interrupted by the closing means, the wheel brake can be operated without any trouble by the brake hydraulic pressure generated by the master cylinder by operating the brake pedal.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle braking device.

FIG. 2 is a longitudinal sectional view of a master cylinder.

[Explanation of symbols]

8 brake pedal 22 load cell (depression force detecting means) 35 reservoir 42 sealing (closing means) 44 relief port (closure means) A accumulator Bc brake caliper (wheel brakes) Mc master cylinder U electronic control unit (control means) V ₁ first opening Valve V ₂ Second open / close valve V ₃ Third open / close valve W Wheel

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Isao Matsuno 840 Kokubu, Ueda-shi, Nagano Prefecture Inside Nissin Kogyo Co., Ltd. (56) References JP-A-62-39351 (JP, A) JP-A-61- 287851 (JP, A) JP-A-63-64858 (JP, A) JP-A-4-243655 (JP, A) JP-A-64-83444 (JP, A) JP-A-2-114049 (JP, A) JP-A-52-140772 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60T 8/00 B60T 13/68

Claims (1)

(57) [Claims] An accumulator (A) for accumulating brake oil pressure and a wheel brake (Bc) for braking a wheel (W).
, A first open / close valve (V ₁ ) interposed between the accumulator (A) and the wheel brake (Bc), and a second open / close valve (V) interposed between the wheel brake (Bc) and the reservoir (35). and ₂₎ the pedal force detection means for detecting the depression force of the brake pedal (8) (22), first, second on-off valve (V _1, V ₂₎ opening and closing control in accordance with the output of the pedal force detection means (22) A vehicle control device provided with a control means (U) which is connected to the control means (U) between a master cylinder (Mc) operated by a brake pedal (8) and a wheel brake (Bc). A normally open third opening / closing valve (V ₃ ) that is opened / closed is interposed, and the third opening / closing valve is attached to the master cylinder (Mc).
Operate the brake pedal (8) when opening (V ₃ ).
And the second opening / closing valve (V ₂ ) and the reservoir
Closing means (42, 4) for interrupting communication between
Characterized in that a 4), the braking equipment for vehicles.