FR2505282A1 - ANTI-LOCK BRAKING DEVICE - Google Patents

Abstract

ANTI-LOCK DEVICE IN WHICH THE MONITORING OF TWO BRAKE CYLINDERS 43, 44 IS PROVIDED BY A COMMON DISTRIBUTOR 32, 6, AND TWO DISTRIBUTORS 22, 7, 8. IN THE CASE OF A HYDROPNEUMATIC BRAKING EQUIPMENT, THE DISTRIBUTOR 32, 6, IS INSERTED IN A PNEUMATIC LINE (CONTROL PIPE 3) AND THE DISTRIBUTORS 22 ARE INSERTED IN A HYDRAULIC BRAKE LINE 41. THE THREE DISTRIBUTORS 6, 7, 8 ARE CONTROLLED BY A PRESSURIZED FLUID. THE FLUID UNDER PRESSURE FOR CONTROL OF THE TWO DISTRIBUTORS 22 IS DERIVED ON A PNEUMATIC LINE (CONTROL PIPE 3), UNDER PRESSURE WHILE BRAKING. 39 IDENTICAL HYDROPNEUMATIC CYLINDERS CAN BE USED FOR FRONT AND REAR AXLES, EITHER THE SAME ELECTRONICS CAN BE USED ON A FRONT AND REAR VEHICLE, OR THE SAME ELECTRONIC CAN BE USED ON A VEHICLE WITH HYDRAULIC BRAKING OF THE FRONT AXLE AND THE TIRE REAR AXLE, AS THE NECESSARY PILOT VALVES 17, 18, 19 ARE IDENTICAL.

Description

The present invention relates to an anti-lock device for the wheels of a

  vehicle with common control of the brake pressure in at least two brake cylinders, having a common brake 3/2-way valve and a 2/2-way distributor specific to each brake cylinder, and hydraulic brake equipment

  in which the 3/2-way distributor is inserted into a

  pneumatic connection connecting a brake valve to a cylinder

  hydropneumatic and 2/2-way valves are inserted into a

  hydraulic braking system connecting the hydropneumatic cylinder

  than brake cylinders Such an anti-lock device is known (patent application of the Federal Republic of Germany published under

  No. 26,568,983). This known device, however, requires a special model.

  Hydropneumatic Cylinder Cial The Electromagnetic Distributors

  2/2 hydraulics with direct control can also

  ensure that a relatively small crossing section

  such weak data are insufficient for application in

  braking components of commercial vehicles.

  The subject of the invention is an anti-lock device which does not have

  these disadvantages. According to an essential characteristic of the in-

  vention, 2/2-way valves are controlled by pressure and fluid

  under control pressure is derived on a pipe under pres-

  during braking The anti-lock device according to the invention

  has the advantage of allowing the use of hydraulic cylinders

  As standard, the 2/2-way valves can be

  be taller and oversee-larger passage sections.

  Finally, in the case of a vehicle with hydraulic brake on the axle

  front and rear wheel brake, the electric control

  that the two axles are identical because the electronic

  Magnetic driving necessary are identical.

  Other features and advantages of the invention will be

  better understood using the detailed description below of a

  Embodiment and accompanying drawings in which: Figure 1 shows the block diagram of an anti-lock device with a group of devices; FIG. 2 represents a variant of the detail of the group of appliances, and

  Figure 3 shows another detail of the device group.

  Hydropneumatic braking equipment comprises a

  brake valve 1, which applies the compressed air from a tank 2 to a control line 3 or purges it to the atmosphere The control line 3 leads to the body 4 of a group of appliances 5, in which a distributor 3/2 6 and two distributors 2/2 7 and 8 are

arranged side by side.

  The 3/2 distributor 6 comprises two seats 9 and 10, a seat

  9 and an exhaust seat 10, between which is

  placed a shutter 11 which can alternately cover one of the two seats 9 and 10 The distributor 6 comprises an intake connector 12, on which is derived a control channel 13 leading to the seat

  intake valve 14, 15, 16 of three electronic distributors.

  17, 18 and 19 These include each

  an exhaust seat 20, 21 or 22.

  The three distributors 6, 7 and 8 each comprise a control chamber 23, 24, 25, closed by a membrane 26, 27, 28 and connected to the inlet seat 14, 15, 16 corresponding The membrane 26 carries a pusher 29 actuating the shutter 11, and the two membranes 27 and 28 of the distributors 2/2 7 and 8 also carry pushers 30 and 31 each actuating a closing ball 32 or 33 A push member 34 or 35 loaded by a spring is further fixed on the other side of each sealing ball 32 or 33 and tends to keep the latter away from a seat 36 or 37 It is seen that the two distributors 7 and 8 have relatively large passage sections The two

  distributors 7 and 8 can also be realized in the form of

tributors with drawer.

  The control line 3 extends beyond the distribution

  3/2 6 by a pipe 3 'leading to the pneumatic side 38 of a hydro-pneumatic cylinder 39 The latter is of a model

  standard for braking equipment, that is to say that no

  The hydraulic side of the cylinder 39 supplies a hydraulic braking line 41 with brake fluid from a reservoir 42. The braking line 41 leads to the two distributors 7 and 8 of the apparatus group 5, in which it divides into two branches 41 'and 41 "of the braking line, leading to the brake cylinders 43 and 44 of the wheels

of the vehicle.

  The rotation of the vehicle wheels is monitored by means of

  45 and 46, which are connected to an electronic control unit 47 The latter is also connected to power lines

  of the electromagnets 48, 49 and 50 of the pilot distributors

17, 18 and 19 -

  The operation of the device described is the following As shown in the figure, the modulation of the braking pressure is carried out in the anti-lock device according to the invention by the

  distributor 3/2 6 on the pneumatic side and with the aid of the two

  scorers 2/2 7 and 8 on the hydraulic side The two hydraulic 2/2 distributors 7 and 8 as well as the pneumatic distributor 6 are controlled by the compressed air applied to the control chambers 23, 24 and 25 by the piloting distributors 17, 18 and 19 This solution has the following advantage: the two hydraulic distributors 7

  and 8 are feasible in the form of simple ball valves, do not

  no difficulty and whose sections must be relative

  because the switching of the distributors 7 and 8, each of which is controlled, is safe even in the presence of high forces.

  passage sections with a diameter up to 4 mm are thus usable.

  The brake valve 1, the device group 5 and the hydro-pneumatic cylinder 39 are furthermore separate components, the brake valve 1 and the hydro-pneumatic cylinder 39 being usual series products. All the components 1, 5 and 39 are connected together. In such a model, the fitting of a conventional brake force regulator according to the load is possible by inserting it into the pneumatic control pipe 3, 3 'as desired.

  or in the hydraulic braking line 41, 41 ', 41 ".

  Finally, we see that the particular nature of the pneumatic control

  Hydraulic valves 7 and 8 can be used to develop a braking concept for a vehicle with a hydraulically braked front axle and a pneumatic rear axle. In this case, it is advisable to monitor the front axle brakes using of a group of devices 5 according to the invention and the rear axle using a group of devices such as that described for example in the patent application of the Federal Republic of Germany published under No. 27 53 992 (distributor Duiana c: pressure 22) The electronic control of the two groups of devices could be

  identical and provided by the same device.

  The operation of the device group 5 still calls the

following remarks.

  A reduction of the braking pressure in the event of protection against blocking is effected by the central 3/2 distributor 6, and

  a pressure maintenance function is provided by the two

  2/2 hydraulic camsters 7 and 8 downstream; a reduction of the

  brake pressure is achieved by reducing the tire pressure.

  in the control pipe 3 'and by increasing the volume by the recoil of the piston of the master cylinder in the cylinder

  Hydropneumatic 39 A maintenance of the brake pressure is effected

  kills in the only hydraulic circuit The possibility of blocking the pressure in a brake cylinder relative to that in the other brake cylinder allows a two-circuit control A hydraulic fluid is however incompressible in principle, it is necessary to prohibit equal opening time of the two distributors 7 and 8 to avoid the pressure compensation in the two brake cylinders 43 and 44 This result is obtained by a shift of the timing

  of the two distributors during the establishment phases of the

  This does not cause any functional inconvenience, since the ratio of the pressure setting phase (holding valve open) to the pressure maintaining phase (holding valve closed) is about 1/6 and asynchronism is consequently very

  Easy to obtain This simple measurement allows you to obtain

  different braking forces in both brake cylinders 43 and 44, even when using hydraulic fluid

  There are, however, vehicle

  which only a determined differential pressure is admissible

  in both brake cylinders to limit the lurching torque.

  This result is obtained by admitting in this case a syn-

  chrone distributors, limited in time.

  It is thus possible to eliminate the pressure difference in

  the two brake cylinders by a synchronous control of the

  scorers 7 and 8, to control a maximum pressure difference by asynchronous control of the distributors 7 and 8, or to control a determined differential pressure, according to the ratio of the durations

  synchronous control / asynchronous control.

  By way of example, it is possible with a pulsed and flat setting of the pressure and a duration of opening of the distributors 7 and 8 of 10 ms for example, to adopt a synchronous / asynchronous control ratio of 4/6, the brake cylinder having the most pressure

  which can only have a definite pressure difference

  minus the lower pressure of the other brake cylinder. It is also conceivable to vary the control of the distributors during the braking operation set according to the

  time or speed of the vehicle, by the ratio of the syn-

  chr / asynchronous At the beginning of the braking or at a high speed of the vehicle, the synchronous control of the distributor ensures the maximum limitation of the lurching torque, while at the end of the braking, a

  More asynchronous control allows a larger lurching torque.

  This measure significantly relieves the driver in the braking start phase, generally critical; towards the end of braking, the larger differential pressure also provides more braking

important.

  In order to optimize the temporal action of elevation and

  decrease in pressure, an additional adaptation of the choke

  may be carried out by means of a choke 51 in the

  braking 41 ', as shown in FIG. 2.

  Additional measures may then be necessary when using single brake cylinders for anti-lock control. In these simple and therefore economical master cylinders, a breather control in a known manner ensures the connection between the piston chamber and the engine. the tank in the absence

braking.

  Such master cylinders controlled by breather present

  the following risk: during rapid braking, the pis-

  Ton is forced back into the bore of the breather by the backpressure and thus risks being damaged. Master cylinders with tilting valves are therefore preferable because they make it possible to obtain high braking pressures for very small strokes. piston The following additional measures are possible depending on

  the invention to allow nevertheless the use of teachers

  Breather controlled cylinders for anti-lock control.

  1 As shown in FIG. 2, a pressure tank 52, of small volume (approximately 2 to 5 cm), and whose pressure is lower than the clamping pressure of the brake shoes, is inserted into the braking line 41, between the hydropneumatic cylinder 39

and the device group 5.

  This pressure tank 52 prohibits the return of the man-

  piston in the breather in case of rapid maneuver

  maltre-cylinder and consequently its functional failure.

  The pressure tank 52 can obviously be integrated into the

device group 5.

  Another possibility to protect the piston sleeve against damage is to prohibit the crossing of the breather by this sleeve during the retreat of the piston, during

anti-lock control.

  This result is possible by inserting into the pipe of

  the control unit of the brake pressure, connecting the distribution

  scorer 3/2 6 outside air, a check valve 53 whose closing pressure is lower than the clamping pressure of the brake shoes, as shown in Figure 3 In the case of a regulation, a residual pressure thus remains in the hydro-pneumatic cylinder 39, which certainly allows the total release of the wheel brake, but does not allow the crossing of the breather by the

piston sleeve.

  In the case of normal braking, the total bleed of the cylinder

  However, the pneumatic valve is operated by the brake valve.

  Of course, various modifications may be made by those skilled in the art to the principle and to the devices which have just been described solely by way of nonlimiting examples, without

depart from the scope of the invention.

Claims (14)

claims   1 Anti-lock device for the wheels of a vehicle with regular   the common pressure of the brake pressure in at least two brake cylinders, comprising a common 3/2 distributor to the brake cylinders and a 2/2 distributor specific to each brake cylinder, as well as hydropneumatic brake equipment in which the brake cylinder 3/2-way valve is inserted into a pneumatic line connecting a brake valve to a hydropneumatic cylinder and the 2/2-way distributors are inserted into a hydraulic brake line connecting the hydropneumatic cylinder to the cylinders   brake, said device being characterized in that the   2/2 (7, 8) are controlled by pressure; and the fluid of com-   under pressure is derived on a pressurized pipe   during braking (control line 3).   Anti-lock device according to claim 1, characterized in that the 3/2 distributor (6) and the two 2/2 distributors (7, 8) are main distributors controlled by distributors of steering (17, 18, 19).   An anti-lock device according to one of claims 1 and 2,   characterized in that the fluid under controlled pressure is the same for the three distributors (6, 7, 8).   Anti-lock device according to any of the claims   1 to 3, characterized in that the shutter of each 2/2 distributor (7, 8) is a ball (32, 33); and each ball (32, 33) is   actuated on each side by a pusher (30, 31, 34, 35).   Anti-lock device according to any one of the claims   1 to 3, characterized by the realization of 2/2 distributors under form of spool valves.   Anti-lock device according to one of claims 4 or 5,   characterized by connecting a pressure reservoir (52) on the braking line (41) between the hydropneumatic cylinder (39) and the 2/2 dispenser (7).   Anti-lock device according to any of the claims   1 to 6, characterized in that the pressurized fluid controlling the distributors (6, 7, 8) is compressed air; and the fluid under   pressure controlled by the two 2/2 distributors (7, 8) is hydraulically   lic. Anti-lock device according to claim 7, characterized in that during the anti-lock control, a reduction of the brake pressure is obtained essentially by a pressure drop in the compressed air circuit and a holding function in the hydraulic circuit.   Anti-lock device according to claim 8, characterized in that for a different control of the pressure in the two brake cylinders (43, 44), the two valves (7, 8) clock   with phase shift the phases of establishment of the pressure.   Anti-lock device according to claim 9, characterized in that the phase shift of the pressure setting phase is variable as a function of time or speed during braking rule.   Anti-lock device according to any of the claims   8 to 10, characterized by the use of a throttle (51) inserted into the braking line (41 ') to optimize the temporal action   during the increase or decrease of pressure.   Anti-lock device according to any one of the claims   8 to 11, characterized by a non-return valve (53) inserted into the   pipe connecting the 3/2 distributor (6) to the atmosphere.