Fluid-pressure and analogous brake systems – Multiple fluid-receiving devices – Multiple motors
Patent
1991-09-20
1993-09-21
Oberleitner, Robert J.
Fluid-pressure and analogous brake systems
Multiple fluid-receiving devices
Multiple motors
3031135, 3031191, 303DIG4, B60T 826, B60T 832
Patent
active
052462765
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
FIG. 2 of DE-A1 34 40 541 discloses an electronically controlled brake force distributor for a diagonal wheel pair in which a 2/2-way valve is inserted in the line leading to the brake of the rear wheel, blocking this line in the de-energised condition. The brake pressure at the rear wheel is regulated, using the slip values determined for the two wheels, by activation of the 2/2-way valve with pulses in such a way that the rear-wheel slip is below that of the front wheel.
Connected in parallel with the 2/2-way valve is a valve unit which permits brake pressure to be fed in at the rear wheel even when the 2/2-way valve is not being activated. However, the pressure which can be fed in by this means is limited.
EP-A1-028332 has also already disclosed an anti-lock brake system in which the pressure at the brakes of diagonally arranged wheels is controlled in common.
SUMMARY OF THE INVENTION
The design and activation, in accordance with the invention, of the valve brings a further improvement in function in conjunction with very favourable configuration in terms of cost. Setter utilisation of the adhesion of the rear axle is achieved in the two-channel ABS employed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a first illustrative embodiment
FIG. 2 shows a diagram for the purpose of illustration and
FIG. 3 shows a further illustrative embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, 1 denotes a brake pedal and 2 denotes a master brake cylinder arrangement for two brake circuits. Only the brake circuit for one wheel diagonal is illustrated. The other brake circuit is of analogous construction. Inserted into the brake line 4 is an ABS brake pressure control valve 3 for the common variation of the brake pressure at a front wheel 5 and a rear wheel 6. This valve 3 is bridged by a nonreturn valve 7.
To approximate the brake force distribution to the ideal brake force distribution, a 2/2-way valve 8 is inserted into the brake line leading to the rear-wheel brake, which valve, in the unactivated condition, brings into effect a pressure-limiting valve. This valve can also be situated in parallel with the 2/2-way valve. It opens when the prevailing pressure difference reaches a certain value.
In order to permit a pressure reduction, a non-return valve 9 is connected in parallel with the 2/2-way valve. The 2/2-way valve 8 is activated by control device 10, to which signals corresponding to the wheel speeds and, in the case of brake actuation, a further signal are fed via terminals 11.
With the aid of the brake-actuating signal, the control device 10 ensures that, upon actuation of the brake, the valve 8 is activated and remains activated until a brake force of about 0.5 g is achieved. The reaching of this point A (FIG. 2) can be detected via the determination of the wheel slips. It is also possible for the actuation of the 2/2-valve 8 to be effected by the switching on of the ignition, the actuation of the starter or the actuation of a switch which is switched on in the brake circuit. These alternative inputs to control device 10 are represented by terminals 17.
In FIG. 2, B.sub.V is the brake force on the front wheel and B.sub.H is the brake force on the rear wheel. The ideal brake-force distributor characteristic is denoted by 12, and the fixed proportioning characteristic allocated to the vehicle but steeper than that of the prior art is denoted by 13. In the activation of the valve in accordance with the invention, the brake force distribution follows the fixed proportioning characteristic 13 between 0 and the point A. After this, the proportioning is varied along the characteristic 12 by activation of the 2/2-way valve with pulses which vary in width or in frequency.
The pressure-limiting valve 20 which is operative in the de-energised position of the 2/2-way valve 8, that is if the control device fails, opens when the pressure difference is .DELTA.p. It produces an offset characteristic 14 which runs parallel to the characteristic 13 with an offset of .DELTA.p. .DELTA.p
REFERENCES:
patent: 4962971 (1990-10-01), Miyake
Jonner Wolf-Dieter
Pajonk Peter
Ballard Josie A.
Oberleitner Robert J.
Robert & Bosch GmbH
LandOfFree
Electronically controlled brake effort proportioning system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electronically controlled brake effort proportioning system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronically controlled brake effort proportioning system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1045375