FR2586220A1 - MULTI-CIRCUIT HYDRAULIC BRAKING SYSTEM - Google Patents

Abstract

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

Description

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  The present invention relates to a hydraulic braking system with several circuits, intended in particular for vehicles

  automobiles, comprising a brake actuation device

  carrying several work chambers which can be pressurized, comprising an auxiliary energy supply system intended to pressurize wheel freix cylinder% and comprising a quick-filling cylinder which is installed on a circuit

  braking, one of the compartments of which communicates with one of the

  pressure reliefs of the brake actuation device via the

  pressure lines, and the other compartment of which is connected to a braking line leading from the actuating device

  brakes to at least one wheel cylinder.

  In a known braking system of the type indicated above (German patent application 35 08 709.9), the amplifier piston enters an annular chamber provided between the master cylinder and the brake force amplifier, this chamber being connected,

  on the one hand, to the pressure chamber of a refilled cylinder

  pide and, on the other hand, to the supply tank. The pressure liquid line leading from the annular chamber to the supply tank has a valve which can be actuated by the

  pressure from the amplifier chamber, which in one of its posi-

  switching positions, closes the pressure liquid passage to the supply tank and therefore allows the pressure liquid to pass from the annular chamber to the pressure chamber of the quick-fill cylinder during braking, and which, in its other position

  switch, connects the annular chamber to the supply tank

  tion. This known braking system has a drawback, namely

  that the brake actuator has a total length

  the comparatively important because, in addition to the working chambers of the

  master cylinder and the brake force amplifier

  ted in series, another working chamber must also be installed

  ted in series with the previous ones.

  The object of the present invention is to provide a braking system which can be connected to an electronic monitoring unit.

  and brake slip regulation, which in the event of a fault

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  this of the amplifier, works with a reduced master surface

  brake cylinder, and the brake actuator of which

  has a particularly short overall length.

  In accordance with the present invention, this object is achieved in that a valve is located on the pressure line connecting one of the compartments of the quick-fill cylinder to the chamber.

  of the brake actuation device, this valve closes

  mant its passage of pressure liquid in case of system failure

  supply of auxiliary energy and / or in the event of a pressure increase in one of the working chambers, and therefore blocking

  hydraulically the stepped piston of the quick-fill cylinder.

  Preferably, the valve which is located on the supply line

  pressure connecting one of the refillable cylinder compartments

  pide to a working chamber, for example to the amplifier chamber

  valve, is designed in the form of a controlled non-return valve, the valve element which controls the passage of pressure liquid from the valve being able to be moved by a valve piston in the direction

  opening, this valve piston being subjected, on the one hand, to the pressure

  auxiliary power supply system, for example from a

  accumulator, and on the other hand, the pressure prevailing in the compar-

  connected to the quick-fill cylinder.

  Advantageously, the valve piston is designed in the form of a stepped piston, the end surface of the small stage of the valve piston being subjected to the pressure of the accumulator, while the end surface of the large stage, close to the valve element is

  subject to the pressure prevailing in the refill cylinder compartment

  quick pleating, one of the front ends of the valve piston being

  provided with a nose or a pusher cooperating with the valve element.

  Suitably, the valve member controlling the flow

  pressure fluid is applied in the closing direction by the pressure prevailing in the working chamber, for example in

  the amplifier chamber, and can be moved clockwise

by the valve piston.

  The multi-circuit hydraulic braking system con-

  advantage of the present invention, namely that in

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  in case of failure of the brake force amplifier, the vehicle

  This can be decelerated without significantly changing the force exerted on the pedal or the stroke of the pedal. In addition, the brake pressure generator has a relatively short overall length since the necessary valve can be installed outside the generator.

  brake pressure proper.

  The various objects and characteristics of the invention are-

  will now be detailed in the description which follows, made to

  by way of nonlimiting example, with reference to the appended figures which represent:

  - Figure 1, the arrangement of circuits of a hydro-

  braking system with several circuits, consisting mainly of

  wheel brakes of a quick-fill cylinder, a device

  actuation valve with tandem cylinder, a modulator, a controlled non-return valve, an auxiliary energy supply system and a pressure liquid supply tank,

  - Figure 2, a sectional view of the non-return valve

  mandée shown in figure 1.

  The slip-controlled braking system intended for a motor vehicle essentially comprises an actuating device, that is to say a hydraulic unit 1 associated with an auxiliary energy supply system 2 and with a valve block or modulator 3 in which the control valves are assembled

  electromagnetic increase and reduction of affected pressure

  tees to a wheel or, respectively, to an axle, a rolling cylinder

  quick pleating 38 and a maneuverable non-return valve 53. In the illustrated embodiment of a braking system with several circuits, the two front wheels or, respectively, wheel brake cylinders 6, 7 and the two wheels and, respectively , brake cylinders

  wheel 4, 5 of the rear axle are ordered in pairs.

  The sensors, which are also necessary for these systems to measure the speed of the wheels, as well as the electronic unit producing the control signals intended for the valves of the modulator.

3 are not shown.

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  The actuating device 1 essentially consists of a brake valve 14, a tandem master cylinder 15 and

  two main valves 16, 17 associated with a prechamber 18.

  In the embodiment described here, the brake valve 14 is designed in the form of a hydraulic brake force amplifier. When the brake pedal 19 is actuated, the force F exerted on the pedal is transmitted, via a rod 20 and a piston rod 21, to an arrangement consisting of two levers 22, 23 articulated I l using a pin 24 and, from 11, to the control piston 25 of the brake valve. Since the force required to move the amplifier piston 40 of the brake valve 14 is significantly greater than that required to move the control piston 25, the latter is first moved to the left, that is, -to say when the lever 22 pivots around its articulation 24 under the action of the force F. The supply system

  in auxiliary energy 2 is then connected to the amplifier chamber

  cator 29 through the entry 27 and the internal holes 28 of the pis-

  command tone 25. Just before was closed the opening 30 which makes

  communicating the amplifier chamber 29 with a supply tank

  pressure compensation 31 when the brakes are not applied. The pressure that builds up in the pressure chamber 29 also acts on the amplifier piston 40 and moves it to the left. The pistons 32 and 33 of the tandem master cylinder are

  then also moved, so that a brake pressure builds up

  blit in the corresponding pressure chambers 34, 35 as well as in the static braking circuits 36, 37 which are connected to it and which correspond to the two front wheels 6 and 7 and, respectively, to the

two rear wheels 4, 5.

  The intermediate element 39, which connects the amplification piston

  tor 40 with tandem master cylinder pistons 32, 33 and which forms a structural unit with the master cylinder piston 32, supports a positioning piston or a positioning sleeve 41 which, in known manner, prevents the pistons from the master -tandem cylinder to move too far to the left at the start of regulation and

  prevents "vacuum regulation" of the working chambers 34, 35.

  If the brake slip regulation is triggered in

  due to an imminent blockage of one or more wheels, the electro-

  valves 16, 17, i.e. the so-called main valves, are excited

  tees, which simultaneously causes the closure of the connecting line 58 leading to the supply tank 31 which is at atmospheric pressure, and the opening of the flow path 55 leading

  from the amplifier chamber 29 to the prechamber 18. The hydro-

  lique, whose pressure is increased due to the supply of auxiliary energy, leaves the prechamber 18 via the connecting channels 42, 43 towards the secondary sides of the two

  master cylinder pistons 32, 33 and from there is transmitted to the

  corresponding work bres 34, 35 via the pis-

  supply tones and holes 44, 45, sealing cups

  46.47 adjacent serving as non-return valves. The posi-

  tction 41 which, before the start of regulation, is floating,

  that is, it is in an intermediate position, is

  placed to the right up to a stop, this movement taking place against the direction of the force F exerted on the pedal and occurring as a result of the pressure increase which occurred previously in

  the compartment 48 of the secondary side of the piston 32.

  Signals are produced by means of a regulator (not

  presented) depending on the rotation behavior of the different wheels 4, 5, 6, 7, which is determined by sensors, these signals

  used to control the electromagnetically actuated valves

  tation and pressure reduction located in the modulator 3. The main valves 16 and 17, which modulate the dynamic introduction of liquid into the static braking circuits 36, 37, as well as the pressure inside the prechamber 18, are also excited

  and switched at the start of brake slip regulation.

  To reduce the braking pressure in the two braking circuits (i.e., in the embodiment described here, the front wheel braking circuit 37 and the rear wheel braking circuit 36), in the event impending locking of a wheel, we use

  valves 59, 60, 61, 62 of the modulator 3, which, after being excited

  tees, establish through the return line 63 a

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  connection between the wheel brake cylinders 4, 5 and, respectively,

  6, 7 and the supply tank 31 being under pressure at-

  which reduce the brake pressure. In a way

  re identical, the pressure prevailing in the prechamber 18 is reduced by means of the main valve 16 and of the pipe 58, as soon as this valve is de-energized. When the main valve 17

  is de-energized, the dynamic introduction of liquid into the precham-

bre is interrupted.

  Suitably, the main valves 16 and 17 are electrically connected in parallel or in series, so that they

  can be switched simultaneously at any time, the commu-

  "open / closed" tation of the two valves 17, 17 being however always opposite. Vehicles with a significant total authorized weight require a high amplification factor to maintain the

  force exerted on the pedal and pedal travel within limits

  your wishes. In the event of an amplifier failure, this results in an undesirable or even unacceptable increase in the forces exerted on the pedal and in a shortening of the strokes of the

  pedal. In the event of an amplifier failure, the brake system

  swimming represented therefore works with a reduced master surface

  brake cylinder, because a quick-fill cylinder 38, connected via a bypass line 68 to the line

  braking 37 of the front wheel brakes 6, 7 remains inoperative. To this end

  fet, the quick-fill cylinder 38 has a stepped bore 39 in which a stepped piston 50 can slide longitudinally, the

  compartment 51 located in front of the small floor 52 being connected to the

  brake line 37 via the bypass line 68, and the compartment 54 located in front of the large stage 56 which can be connected to the flow path 55, intended for the prechamber 18, by

  through the pressure line 57 through an an-

  ti-return controlled by pressure 53 and pressure line 69.

  When the braking system is intact and the brakes are applied, the controlled non-return valve 53 opens the passage

  of pressure liquid leading from pressure line 69 to the

  -7- pressure tank 57 and compartment 54, so that the liquid

  pressure prevailing in compartment 51 is sent to the circuit

  braking circuit 37 via the bypass line 68. The controlled non-return valve 53 is shown in detail in FIG. 2. It consists of a valve piston 72 which is tightly guided in the valve casing 71, one of the end surfaces 73 of which is subjected to the pressure of the accumulator 70 which communicates with the orifice 74 via the pipe

  pressure 75. The orifice 76 of the valve 53 communicates with the reservoir

  see supply 31 via line 81. The over-

  end face of the valve piston 72, close to the valve element 78, is subjected to the regulated pressure which propagates to the chamber

  amplifier 29 via port 79 and the connector

  pressure pick 69. Finally, the orifice 80 of the valve 53 is connected to the

  compartment 54 of the quick-fill cylinder 38 via

  diary of the pressure line 57. As long as the pressure prevailing at

  the interior of compartment 82 of valve 53 corresponds to a pressure

  predetermined accumulator capacity (eg 180 bar), the valve piston is in the open position (on the right, looking at the figure) and its pusher 83 takes off the valve element 78 from its valve seat 84, so that pressure fluid can pass from port 80

  to compartment 54 of the quick-fill cylinder 38 via

  diary of the valve chamber 85, the annular chamber 86, the orifice 79 and the pressure line 57. The increase in pressure inside the compartment 54 then displaces the stepped piston 50 against the force of the piston spring 87 (towards the

  left) and sends the pressure liquid in the comparator

  51 in brake circuit 37 of the front wheels (i.e.

  re in the wheel cylinders 6 and, respectively, 7). If a de-

  failure occurs in the auxiliary energy supply system 2 or, respectively, if the pressure of the accumulator 70 falls below a determined level, the valve piston 72 then returns to the initial position shown in the figure 2 and the passage

  of pressure liquid between the valve chamber 85 and the an-

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  ring 86 remains closed, so that the stepped piston 50 keeps po-

he has just adopted.

  The pressure liquid remaining in the compartment 54 and, respectively, in the line 57 cannot flow back due to the closing of the valve, so that all of the pressure liquid, displaced only by the force exerted on the pedal by by means of the cylinder pistons 32, 33, serves to establish a pressure in the braking circuit 37. Suitably, the

  effective surfaces of the stepped piston 50 and the non-return valve

  noeuvrable 53 are adapted to each other so that the valve 53 closes when the regulated pressure (in the flow path

  ) is equal to about 70% of the pressure prevailing in the accumulator-

70.

  When the pressure inside the amplifier chamber 29 reaches that of the accumulator 70, the valve piston 72 returns to the initial position, which has the effect of blocking

  the piston 50 of the quick-fill cylinder 38.

Claims (4)

  1. Hydraulic braking system with several circuits, intended in particular for motor vehicles, comprising a brake actuation device (1) comprising several working chambers (29, 34, 35) which can be pressurized, comprising a system auxiliary power supply (2) for pressurizing wheel brake cylinders (4, 5, 6, 7), and comprising a quick filling cylinder (38) which is installed on a braking circuit (37 ), one of the compartments (54) of which communicates with one of the pressure chambers (29) of the brake actuation device (1) by means of pressure lines (69, 63, 55),   and the other compartment (51) of which is connected to a brake line   ge (37) leading from the brake actuation device (1) to at least one wheel cylinder (6, 7), characterized in that a valve (53) is   located on the pressure line (69) connecting one of the compartments   elements (54) from the quick refill cylinder (38) to the working chamber   vail (29) of the brake actuation device (1), said valve closing its passage of pressure liquid in the event of failure of the   auxiliary power supply system (2) and / or in case of increase   indication of the pressure in one of the working chambers (29), and   thus hydraulically locking the stepped piston (50) of the refill cylinder quick pleating (38).   2. Hydraulic braking system with multiple circuits   form in claim 1, characterized in that the valve which is   located on the pressure line (69) connecting one of the compartments   elements (54) of the rapid filling cylinder (38) to a working chamber, for example to the amplifier chamber (29) of the brake actuation device (1), is designed in the form of an anti-valve - controlled return (53), the valve element (78) which controls the passage of pressure liquid from the valve being able to be moved by a valve piston (72) in the opening direction, said piston   valve being subjected, on the one hand, to the pressure of the supply system   tion of auxiliary energy (2), for example of an accumulator (70), and - 10 - 2586220   on the other hand, at the pressure prevailing in the compartment (54) of the cy-   quick fill liner connected to it.   3. Hydraulic braking system with multiple circuits   form in claims 1 and 2, characterized in that the piston   valve (72) is designed as a stepped piston, the surface ex-   the small stage of the valve piston (72) being subjected to pressure   of the accumulator, while the end surface of the large stage, close to the valve element (78), is subjected to the pressure prevailing in the compartment (54) of the quick-fill cylinder (38), one of the front ends of the valve piston (72) being provided with a   nose or pusher (83) cooperating with the valve element (78).   4. Hydraulic braking system with multiple circuits   form according to any one of the preceding claims, characterized   in that the valve element (78) controlling the passage of liquid from   pressure is applied in the closing direction by the pressure   gaining in the working room, for example in the bedroom   plifier (29), and can be moved in the opening direction by the valve piston (72).