DE1555203A1 - Brake system for vehicles, in particular motor vehicles - Google Patents

Description

Brake system for vehicles, in particular motor vehicles The invention relates to a brake system for vehicles, in particular motor vehicles, in which the brake actuator, e.g. a first system of wheel brakes and, on the other hand, a hydraulic master cylinder which belongs to the second system of wheel brakes For this purpose, three measures are proposed in combination: First, each of the two brake systems, as is known per se ($, B, German patent specification 866 151, French patent specification 'r 160 251), should be assigned to each wheel, so that the If one brake system fails, all four wheels are braked. The second measure is best This means that the master brake cylinder is only connected directly to the brake cylinders of one wheel group belonging to the second system, e.g. the rear wheels, and, with the brake pressure generated, actuates a switching valve that controls the pressure of a second accumulator to the brake cylinders of the other belonging to the second system Wheel group, e.g .: the front wheels, forwards. The meaning of this measure, which is based on the principle (control of a brake auxiliary force by the brake pressure generated in a master brake cylinder for another Brr: inssy: 3tetn) by the, deuti @ che e'.itent srhrift 822 493 bjka: in.ti: 3t, lies in the following: There is only a very small volume of hydraulic fluid to operate the sequence valve. must be displaced in the master cylinder, one comes with such. System with the same braking effect with only about half the displacement volume in the master brake cylinder than in a system in which the brake cylinders are directly acted upon on all four wheels. A smaller displacement volume in the master cylinder means, with the same spring travel and the same foot force, a smaller piston diameter and thus a higher brake pressure. The higher brake pressure makes it possible to brake more sharply in emergencies and if the first brake system fails.

The third measure to increase operational safety is in accordance with the invention proposed that in one of the brake systems, preferably in the first, in the newspaper about the brake cylinders of that group of wheels, in the example of the rear wheels, which is operated directly from the main brake cylinder, a shut-off valve is installed, that in the event of a pressure failure in the line between the second reservoir and the Sequence valve shuts off automatically.

Namely, it could happen once that as a result of damage or the like. the connecting valve controlled by the master brake cylinder for braking, for example, the front wheels does not receive any pressure medium from the second accumulator so that this braking of the front wheels would fail. The front wheels would then only be operated by one braking system, while the rear wheels would continue to be operated by both systems: Such a braking force distribution would be dangerous. The above-mentioned shut-off valve ensures that in this case only one system acts on the rear wheels.

In the interest of keeping the actuation travel of the holding valve small this is best designed in such a way that it essentially consists of a piston valve consists of the Zta-- and outflow of the v.c, ii the second reservoir coming pressure medium in bzit: from eiuein vor; ler one: 3ttrnaeite des Kolherischieber 11-'1111i1 cier : r 1. t fleh L) rem: 3zyl: i r learn in Connection. Is established while the other end face of the piston - a valve from that coming from the main burner cylinder Drue. @ Ufiittel is applied.

The shut-off valve can be designed in such a way that the shut-off occurs a spool valve is controlled, which is in the open position by the pressure in the newspaper between the second store and the sequence valve against one Stop is pressed and in the blocking direction from the pressure in the newspaper is applied to the brake cylinders.

The brake system can be designed in such a way that a pressure limiting valve is arranged in the pressure line of the one, preferably the first, system leading to the rear wheel brake cylinders. For such systems, which are also provided with a shut-off valve according to the invention, it is proposed with regard to a structural union that the shut-off element of the shut-off valve, for example designed as a ball valve, is also the shut-off element of the Druckbegreazungsventihs. The arrangement may so be here is that the piston slide of the Druckbegrenzungeventils and the shutoff valve are arranged axially one behind the other, that the hydraulic means gange bore from the brake valve via the hollow piston slide of the Abaperrventils and arranged in this slider, under Pederdruek ball valve by a stirpeeitige off this Slide gets into the space between the two slides, from which the newspaper goes to the brake cylinders of the rear wheels, and that the ball valve with a properly operational brake system below the maximum pressure determined by the pressure relief valve against the spring pressure by a pin attached to the piston slide of the pressure relief valve is held in the opening position.

In the drawing 'an embodiment of the invention is shown. . Fig.1 shows the entire brake system in the circuit diagram, and Fig.2 shows a section through the control unit block. the plant.

In FIG. 1, 10 is the frame of a traveling in the direction of arrow 11 Passenger car indicated. For the sake of clarity, only the brakes are Springs etc. are shown on one side of the vehicle. The front axle 12 and the rear axle 13 are supported against the frame 10 by air springs 14 and 15. At 16 and 17 are the parts of the wheel brakes that are firmly connected to the wheels, e.g. the Disc brakes, designated. The wheel brake cylinders of the front wheel carry the designations 18 and 19, those of the rear wheel the designations 20 and 21. Each of the wheel brake cylinders acts on a braking member, e.g. on the caliper of a Disc brake, -a.

An oil pump 22 driven by the vehicle engine sucks oil from a container 23 and supplies in a known manner via an accumulator charging valve 24 a first pressure accumulator 25 and a second pressure accumulator 26, in which the oil is under the pressure of a compressed gas volume 27 and 28, respectively. Non-return valves 31 and 31 'and an intermediate storage device 31 ″ can be installed in the supply lines 29 and 30 to the accumulators 25 and 26. The brake pedal 32 is available via a binding, 33 Xt a balance beam 34 in connection. The one free Zudi dee li -: @ .: ' The balance beam 34 is connected to the operating rod 35 of a valve 36, the other free end of the balance beam 34 stri Operating handle 37 of a main brake lever 38 angele. The brake valve 36 directs in bekemter wines that from the .S ' p e i ahe : 5 ' . Via the line 39 brought pressure medium through dis Lines 40 - 43 to the wheel brake actuators 19 and 21 W i From the master brake cylinder 38, the in the line. I; '-` 3 and 441 located pressure means through which the wheel. = x. 20 and on: sequence valve 4 bea.ufaohlat is, s_ .., ` The connecting valve 45 conducts this from the reservoir 26 via lines. .46 and 46.1 printed media brought in by a newspaper 4? to. Wheel brake cylinder 18.

In the line harness 42/43 leading to the wheel brake cylinder 21, a pressure limiting and shut-off valve 48 is arranged, which limits the pressure in the line 43 to a maximum value. The size of this maximum value is automatically set as a function of the pressure in the air spring 15, for which purpose a connecting line 49 between the air spring 15 and the valve 48 is required. The shut-off part of the valve 48 is actuated via the newspaper 46.

fig.2 time, as in the constructional training the essential control devices the braking system are combined in one block. From top to bottom, ri are arranged the brake valve 36, the Rüekachlagveritl 31, the shut-off and pressure relief valve 48, the retaining valve 45 and the main brake cylinder 38.

The structure of the individual control units can best be explained using the functionality of the system: lQ with one. normal braking process when the system is properly operational, when the brake pedal 32 is depressed, the force transmitted by the rod 33 is distributed over the balance beam 34 to the actuating rods 35 and 37, The actuating rod 35 moves with its end face 50 afterwards Traversing the idle path 5.1 a valve body 52 to the left, eo datdae * from the storage 25 coming pressure oil Tiber die - Newspaper 39r and the channel 53 can get into the room 54. @ 1) The pressure now builds up, which pushes the valve body 52 to push back to the right: seeks what happens when this Dcuokkr't larger than that of the Puss in the bar 35 over- - @ outstanding strength will. The pressure s-.feht located in space 54 also aut, d *. Wheel brake cylinder 19 of the Leitän: n- 40 , d- 4m: 'tm. Room 54 is connected. Pevier arrives ._U xeser caer ° t: Meitünp- 42 zu. 'derbe @: "r = te:" @ h des Vent! Ls 48. The pressure medium enters the cavity 55 of a piston valve 56 a. This piston valve is held by one in front of his left Face at 58 standing pressure to the right against one Stop 57 pressed. The pressure in the space 58 comes from the Memory 16, which communicates with room 58 via channel 46 stands. The slide 56 has an axial exit bore 59, which can be blocked by a spring-loaded ball 60. In the position shown, however, the exit hole is through a pin 61 held open. The pressure medium can so in a Reach space 62, from which it is via line 43 to the Brake cylinder 21 of the rear wheel arrives. Accordingly, the Wheel brake cylinders 19 and 21 of the first, through the brake valve 36 controlled braking system evenly pressurized. The operating rod 37 generates 1: n des in a known manner Pressure chamber 63 of the master cylinder 38 a brake pressure, the dinerseite about the newspaper 44 to the wheel brake cylinder. 2O des Rear wheel arrives and on the other hand via the channel 44 'in a space 64 comes in which it acts on a piston valve 65 hits and shifts to the left. Here-one opens on the Piston valve 65 attached pin 66 a ball valve 67, the pressure medium (newspapers 46 and 460) opens the Veg into a room 68 from which it via the newspaper 47 to the brake cylinder 18 of the front wheel and . via an outlet 68 # controlled by the piston valve 65 sum container 23 can get back. The sequence valve isfso designed that the pressure in the newspaper 44 is approximately the same size Pressure in the 'line 47 corresponds. Accordingly, the iladbreme- .: linder 18 and 20 of the bet lbremseyetema also - the same-. idly pressurized. . Bite-stronger braking., D ü:, if, the- pressure. In the line -43 and, ixi the rear wheel brearo cylinder 21 'a certain j4' rert ' cross wild., becomes through the .d = also: im, Räuii '62 vn @@ those * glelch- great brue si # @ tibeechiebr '° c.er `with e1: -1blbin 70 verbunddri i is. moved to: right: `Aüf-" dem., -,. Piston 70 is the air pressure in space 71, which is the same as the pressure in the air spring 15 of the rear wheel, since the. Air spring 15 and space 71 are connected by newspaper 49. The piston slide 69 will move to the right when the force exerted on it by the hydraulic pressure in the space 62 is greater than the oppositely directed force exerted by the air pressure in the space 71. The higher the static spring load on the rear wheels, i.e. the higher the pressure in space 71, and the greater the pressure in line 43 and in space 62, the piston slide 69 will first move to the right Coordination between the air pressure and the hydraulic pressure. The activation of this spring is necessary because the respective maximum pressures required for the rear wheel braking for the different static loads on the rear axle are in a different relationship than the respective pressures in the air springs of the rear wheels If the piston valve 69 moves to the right from the position shown, the needle 61 @ attached to the piston valve 69 also moves to the right, so that the ball valve 60 is closed and the pressure in the space 62, and consequently also the pressure in the rear wheel- , can not continue to increase brake cylinder 21st the first braking system continues to work over time ungen 40 and 41 on the front wheel brake cylinder 19 with a pressure that corresponds to the foot force introduced on the pedal 32, while the pressure in the rear brake cylinder 21 and in the line 43 no longer increases even when the foot force increases, but at the respective cut-off pressure stop.

In the event that there is no pressure in the memory 6 and the lines and spaces directly connected to it as a result of a malfunction or a defective condition, in which case the connecting valve 45 can no longer pass any pressure into the line 47 to the front wheel brake cylinder 18 is precautionary Met that-then is not mehr.wirkeam at the rear of one of the two braking systems, otherwise a dangerous, would occur in relation too heavy braking on the rear wheels. If the memory 26 no longer has any pressure, whether the newspapers 46 and 461 are also depressurized, with the result that the piston slide 56 is displaced to the left by the pressure in the space 62 , the ball 60 being in front of the The outlet opening 59 sets and prevents pressure medium from being placed in the newspaper 43 and thus to the rear wheel brake cylinder 21 . Thus, only one brake cylinder, namely cylinder 19 and cylinder 20 , then works both on the front wheel and on the rear wheel.

If the accumulator 25 and the rooms connected to it should become druoclonic, the braking takes place via the main brake cylinder 38 in connection with the locking valve 45, whereby again only one brake cylinder is active on the front wheel and one on the rear wheel , namely cylinder 18 finally and the cylinder 20. Should both accumulators 25 and 26 are pressurized, acts at least another Radbremezylinder, namely the directly actuated by the master cylinder 38 cylinder 20 rear wheel.

Claims (1)

, atentanUrtiche: 1. Brake system for vehicles, in particular motor vehicles, in which the brake actuator, e.g. brake pedal, acts on a balance beam which is connected on the one hand to a brake valve for the controlled transfer of accumulator pressure to a first system of wheel brakes and on the other hand to a hydraulic master brake cylinder, belonging to a second system of wheel brakes, characterized in that * when assigning each of the systems (19,21 and 18,20) to each wheel of the main brake cylinder (38) directly with the reasonable impaired only the second system brake cylinder (20) the one wheel group, e.g. the rear wheels, and with the generated brake pressure actuates a supply valve (45) which controls the pressure of a second accumulator (26) to the brake cylinders (18) belonging to the second system of the other wheel group, in the example the front wheels , forwards, and that in one of the braking systems, preferably in the first, 'in the. Newspaper to the brake cylinders (21) - that wheel group, in the example of the rear wheels, which is operated directly by the master cylinder (38), a shut-off valve (48) is installed , since if the pressure 3n of the newspaper F (46, 46 ') fails, between the second memory (26) and the Zusehaltvsntil (45) automatically shut off. z. Brake system according to Claim 1, characterized. that the switch-on valve (45) essentially consists of a piston valve (65), which controls the supply and hbfl.Li3 of the pressure valve coming from the second spoke = (26): La b $ w. the end '' the piston valve (65) in front of one end located space (68) controls that with the combustion cylinders (18) is in connection (4?) , While the other end face of the piston valve (65) of that of the master brake cylinder (38) coming (44) pressure medium is applied. 3. Brake system according to claim 1 or 2, characterized by 4, that the shut-off overall by a piston slide (56) is controlled, which is in the open position by the pressure . in the newspaper (46) between the second store (26) and the shut-off valve (45) against an oil layer (5'T) is pressed and in the shut-off direction of the Push on the line (43) to the (21) is applied . 4. Brake system according to one or more of the preceding Claims, characterized in that $ .H. as spherical valve (60) trained k boch4 * orig4 deg; Shut-off valves at the same time the shut-off device a Driadh'begrs'azungeventils is that in the to the Einterradlbreäseylindern (21) leading pressure line (42,43) the one n, 'vorzueweiee des first, systems is arranged. Brake system according to the previous inspection, thereby indicates that the piston valve (69.b ».56) the Pressure relief valves and axial shut-off valves one behind the other, arranged s1 protrudes the hydraulic medium from the 8're = nsa eti'il (36) ütüden hollow ea piston valve e '(56) of the onperrvent @ lA. and e`in into the : -. # .) Ä7 slider a, eonstree, under Federdrualk ° itobead * s' $ ugeiv * xtil @f; 0) by a etirneeiti.geusgen $ 4bo b ! i (gej @ den Gchle -er (56) in the Bauü ,, ( 62) zwipgbg , d®w: bdidepi 4Gh @@ 1: n arrives, 01 , e (2 1 ) der . from de * die Zeitig g ; 11 Backg @? E atgey, '- .1d d = aC: @ g @ t : #int., (6Q) bei properly operational brake system is held in the opening position below the maximum pressure determined by the pressure limiting valve against the spring pressure by a pin (61) attached to the piston slide (69) of the pressure limiting valve.