CS203317B1 - Connection for applaince for permanent signalling of the failure of one braking circuit of hydraulic double-circuit vehicle brakes - Google Patents

Description

The invention relates to a permanent device. single fault indication. the brake circuit for hydraulic dual - circuit brakes of vehicles, in particular motor vehicles,. provided on the one hand with a piston mounted in the cylinder body tightly and displaceably and arranged between the movable support. discs in both pressure areas of the two brake circuits, the support discs being biased by the centering springs against the bearing edges of the cylinder body in the piston face regions and displaceable away from the piston against the force of the centering springs; which are operated by a piston.

There is known a pressure equalization device for dual-circuit brakes according to German patents 526 588 and 558 036, which has a single cylinder, the ends of which are provided with stops limiting the piston travel, in which both sides of the pressure equalizing piston are connected to one brake the piston divides the cylinder body into two pressure spaces.

The main disadvantage of this known pressure relief device is that although one of the brake circuits is leaking, the circuit is displaced. the piston closes, but it needs to be completely repaired. ote2 device. · Boil to bring the piston back to its center position. In addition, the driver is not signaled in any way. Therefore, the discarding of one of the brake circuits can only be determined by knowledge. driver. From this, it is apparent that the pressure relief device lacks two essential technical features, namely a brake circuit fault signal, in particular a permanent signal, and the impossibility of automatically adjusting the piston to a central position after the brake circuit has been removed.

Further, there is known a warning device for dual-circuit motor vehicle braking devices according to German Patent Specification No. 1 605 881, in which a single cylinder with an internally located piston is also used, which also divides the cylinder body into two pressure spaces. The piston is held in the bore in its central position by two biased springs. These pre-tensioned springs are supported. one side against the cylinder body and the other side against the piston. The resiliently biased switch pin maintains the piston in a fault signaling position, i.e., the contact pin force of the switch pin must be greater than the biasing force of the bias springs in order to provide continuous signaling of the brake circuit failure. This, however, causes increased wear due to the contact force on the switch pin and the piston. In addition, there is a great danger of cutting off the switch pin or at least bending it with relatively steep control cams on the piston. ·

Besides, they are in the field. hydraulics, as can be seen, for example, in the book "Handbuch der Standardhydraulik und Pneumatik der DDR", Part 2, Special Edition 1965, known valve valves according to TGL 10 931, whose valve pistons, which are arranged as floating, are maintained in their center position by two pre-stressed centering springs. These centering springs are arranged on both sides of the piston, in each case between one fixed and one longitudinally displaceable stop, so that the piston permanently returns to its initial or intermediate position. When the piston is displaced, however, the opposed pre-tensioned centering spring does not exert any additional pressure on the piston, since it engages with the sliding one. . . stop to a fixed stop edge. .

The main disadvantage of this arrangement is that the directional control valves of this design are only applicable to hydraulic actuators.

There are also known warning and signaling devices according to the patents of German Patent Nos. 1,655,279 and 1,655,280, in which, as a floating arranged piston, it is also maintained in its central position by two pre-tensioned centering springs, these centering springs being five. arranged between a fixed and longitudinally displaceable stop.

The main disadvantage of these devices is that they lack any signaling or permanent signaling of the brake circuit failure. In addition, the production of piston and longitudinally displaceable and fixed stops. of centering springs relatively technologically expensive. ,.

Also known is a warning and signaling device according to German Patent No. 1 655 538 for hydraulic dual-circuit braking devices in which the piston with the central control groove is arranged coaxially displaceably in the hollow piston against the force of the biased springs.

The main disadvantage of this arrangement is that the central control groove provided with the piston responds to slight pressure differences between the pressure spaces arranged on both sides, which move it from its central position, thus signaling a failure of one of the brake circuits i when no failure occurs. This is due to the fact that the centering springs have no stop on either side of the piston.

French Patent Specification No. 1,468,338 also discloses a device for permanently signaling a failure of a single brake circuit for hydraulic dual-circuit brakes.

The main disadvantage of this known arrangement is that a mechanical locking of the piston in the cylinder body is necessary to provide the signal even after the braking is completed. After a pressure drop in one of the two brake circuits, the piston remains on the side of the damaged brake circuit, the ball extending into the guide bushing and the piston and cannot be removed from the guide bushing without external intervention. Since in this position the contact of the warning circuit is closed at the same time, it acquires. the indication of which of the two brake circuits is damaged. The mechanical locking of the piston with a ball provided between the piston and the guide sleeve ensures a permanent signaling.

After the failure of the respective brake circuit has been remedied, the ball must be removed by mechanical action from the guide bushing to return to the narrow partition in the middle position, the piston being held in its middle position by springs that are provided on both sides.

These disadvantages are overcome by the circuit according to the invention, which consists in that the switching element is connected via a series resistor to the ignition electrode of a thyristor connected to the control light circuit.

The main advantages of the device according to the invention compared to the prior art are that there is no need for mechanical locking of the piston after the pressure drop in one of the brake circuits in the respective end position, since a permanent fault indication is provided by the thyristor. In addition, the solution provides a permanent signaling of the brake circuit failure, even if the brake or brake pedal is not actuated, and the device automatically returns to its initial position as soon as the fault has been eliminated without external intervention. ·

The invention is explained in more detail below with reference to a drawing.

The diagram shows the circuit diagram of the brake circuit fault signaling device based on the pressure difference with the pulse transmitter and the signaling circuit with integrated function memory connected to it.

A piston 2 with two cylindrical extensions 2a, 2b is mounted in the cylinder body 1 and furthermore are in. pressure spaces 3, 4 are provided therein, in which longitudinally movable support discs S, 6 and centering springs 7, 8 are arranged. The sealing rings 12, 13 are provided on the piston 2 to seal it against both pressure spaces 3, 4. The piston 2 is provided with a central recess · 2c in which a ball is mounted. 9. The ball 9 touches. switch or pin 00 of the switching element · 11.

The abutment edges 18a, 19a and the plugs 18, 19 represent the outer abutment surfaces of the centering springs 7, 8 and at the same time comprise the pressure connections 14. 15. Outside, the pressure spaces 3, 4 are sealed by the outer sealing rings 20, 21. 18, 17 limit the spring travel of the centering springs 7, 8 in the inward direction. Before ignition electrode of the thyristor Th is preceded by a series resistor R. · The signaling circuit is still ranked _ψϋ Β source of power and control light · Kl.

The operation of the device according to the invention is described below.

If there is a predetermined pressure in both brake circuits, the piston 2 is in its central position. On failure. one of the brake circuits and thus, even if the predetermined permissible pressure difference in the two brake circuits is exceeded, the piston 2 is moved. in the direction of the discharge port 14, 15 to which it is connected, a fault brake circuit. As a result, the pressure-free brake fluid escapes from the respective pressure chamber 3, 4 and the corresponding centering spring 7, 8 is compressed. The ball 9 is lifted from the central recess 2c of the piston 2 to actuate the switching pin 10 of the switching member 11. By connecting the contacts of the switching member 11, current flows through the resistor R and actuates the ignition electrode Th. once the thyristor Th is connected, it continuously flows through it until the battery circuit of the vehicle is interrupted. This ensures that the warning light K _L is permanently illuminated when the brake or brake pedal is not applied and thus indicates to the driver a failure of one of the brake circuits. When braking is complete, piston 2 returns

Claims (1)

Involvement of a device for permanent indication of failure of one brake circuit in hydraulic dual-circuit brakes of vehicles, in particular motor vehicles, equipped with a piston mounted in a cylinder body tightly and displaceably and arranged between movable support discs in both pressure spaces of two brake circuits. By means of the centering spring 7 or 8, they are pressed back into their middle position by the biasing spring 7 or 8. Small differences in brake pressure! The circuits, which may occur even with intact brakes, cannot, due to the preload of the centering springs 7, 8, lead to the displacement of the piston 2 from its central position. Moreover, the support disks 5, 6 ensure that the centering spring 7, 8, which is in the pressure chamber 3, 4 of the intact brake circuit, does not exert additional pressure on the piston 2. In order to achieve a long service life of all wear parts, in particular the sealing rings 12, 13, the switching path of the piston 2 is selected as small as possible. Therefore, the degree of freedom is longitudinal. sliding support discs. 5, 6 is approximately the same as the radius of the ball 9. It follows that the total switching path on both sides has a value corresponding to the diameter of the ball 9 for the piston 2 and thus for the sealing rings 12, 13. that the central recess 2c of the piston 2 is also chosen according to the size of the diameter of the ball 9, that is, its size corresponds to that of the diameter of the ball 9. The circuit according to the invention is determined. for hydraulic dual - circuit brakes' of vehicles,. especially motor vehicles. VYNALEZU. the cylinder bodies are played in the piston face regions and are displaceable away from the piston against the force of the centering springs and, secondly, by the current control circuit with control indicator, which are actuated by the piston, characterized in that the switching member (ii) is over ) is connected to the ignition electrode of a thyristor (Th] connected to the control light circuit JKJ.