DE2106849A1 - Pressure medium-operated Bremsvor direction - Google Patents

Description

Patent application

ÄÜTOüOTIVE PRODUCTS COl-EPAJTY LIMITED

Tachbrook Road, Leamington Spa, Warwickshire; England

Pressure-operated braking device

The invention relates to a pressure medium-actuated braking device for vehicles, in which the maximum Braking force on at least one pair of wheels can be controlled by a shut-off device that is dependent on the vehicle load is and in which the brakes of said wheels of two separate pressure medium pressure arrangements with one can be actuated simultaneously on both jointly acting control devices.

As is known , one of the factors that determine the adhesion of the vehicle tires to the road surface is the load on the vehicle wheels. Accordingly, the brakes of a vehicle can be applied more strongly under all road conditions and without the risk of slipping when the vehicle is heavily loaded.

It is becoming more and more common today, especially in heavy trucks, dual-circuit brake systems operated by pressure medium

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Poetscheckkonto Essen 47247 · Commerzbank AG, Düsseldorf, Deposltenkasee main station

provide both of which apply the brakes on a specific pair of vehicle wheels,

The object of the present invention is to to provide a shut-off device in vehicles with such a dual-circuit brake system, the setting of which is changes with the loading of the vehicle, so that according to the load, the pressure in both pressure medium-actuated Braking systems is exerted on at least one pair of vehicle wheels, is limited, this shut-off device should ensure that if one brake circuit fails, through the second Braking system the maximum braking pressure is maintained on the brakes,

According to the invention, this object is achieved by that the shut-off pressure medium passages for transmitting the pressure medium pressure of the respective pressure medium pressure arrangement has on the associated brakes, the pressure medium passages with each other separate Yerschluß members are provided, which by means of a joint acting on both of depending on the vehicle load and opposed to the pressure medium pressure acting on the brakes Spring are held in the open position; the brakes are also active if one of the pressure medium pressure arrangements fails effective from the other pressure medium pressure arrangement with the whole against the spring pressure Brake pressure can be applied.

In the braking device according to the invention, the separate locking members are each one axially at a distance from the other bearing surface arranged in a bore, the first closure

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member via a first plunger and the second locking member Via a second plunger arranged between the connecting elements in operative connection with the common spring and the tappets are designed with equally large effective areas. The downstream The surfaces of the locking elements and the two plungers are not subject to a pressure medium pressure that is opposite to the spring pressure, the upstream surface of the first closure member and the first plunger are with a spring pressure applied pressure medium pressure in the same direction.

It is expedient in the braking device according to the invention the seat of the second closure member as an opening with at least one of the plunger surface same passage cross section

In the braking device according to the invention, stops are used to limit the axial, opening displacement the plunger provided.

Advantageously, in the braking device according to the invention, the shut-off device is on the body of the with the Brakes equipped vehicle arranged, and there is a connecting link between a stop of the common Spring and a vehicle axle with a counter to the force of this spring with increasing vehicle load decreasing effective spring provided "

An exemplary embodiment of the invention is described in detail below with reference to the figures:

Fig. 1 shows schematically a pressure medium-actuated brake system for a vehicle according to the invention;

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Fig. 2 shows the shut-off device of this braking device in detail.

The one in Pig. 1 illustrated braking device is a fluid pressure braking system with split flow and pressure accumulator, in which the brakes 11 on the front wheels of the vehicle are operated via fluid pressure motor cylinders 12 and the brakes 13 on the rear wheels of the vehicle by corresponding fluid pressure motor cylinders 14 and 15. With a pump Shut-off valve unit 16, the pump of which is driven by the engine or the gearbox of the vehicle, pressurized fluid is taken from a storage vessel 17 and fed to the two pressure accumulators 18 and 19 via a separating valve 21, the shut-off valve causing the pressurized fluid delivered by the pump to enter the storage vessel 17 is supplied when the accumulators are filled _o

The pressure accumulators 18 and 19 belong to two separate pressure medium pressure arrangements, one of which is the pressure accumulator 18, the engine cylinders 12 of the front brakes and the rotor cylinders 14 of the rear brakes contains, while the other from the pressure accumulator and the engine cylinders 15 of the rear brakes consists. A control valve 22 actuated by the driver by means of the pedal 23 consists of separate valves for the two pressure medium pressure arrangements, each of which is the connection between the I-iotorzylindern and the pressure accumulator of the associated system normally interrupts and the hot cylinder connects to the storage vessel 17, while by actuation of the control valve by the driver

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Connection between the motor cylinders and the storage vessel interrupted and between the Hotorcylinders and the accumulators is produced.

In the braking device according to the invention is in the connecting lines between the driver actuated control valve 22 and the motor cylinders 14 and 15, a shut-off device 24 (Pig. 1) installed. The function of the isolating valve 21 is to prevent the pressure fluid pump from flowing back To prevent hydraulic fluid from the accumulators, it continues to do so in the event of a Leaks in a pressure accumulator or the associated pressure lines terminate both systems against the pump and also closes the undamaged system against the leaky system from, so that this is still available for actuation of the brakes until the pressure of the Pressure accumulator of this system is exhausted »

Hach Pig. 2, the shut-off element consists of a valve body 25 with outlets 26 and 27, which are connected to the Hotorzylindern 15 and ₀ 14, and inlets 28 and 29, which are connected with the two valves of the control valve 22 and above with the pressure accumulators 19 and 18, respectively are. As will be described further below, means are provided for controlling the connections between the passages 26 and 28 or 27 and 29, by means of which it is effected that said connections are interrupted when the pressure in an engine cylinder determines one due to the vehicle load Value exceeds.

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A bore within the valve body 25 consists of parts with different diameters, namely one part 30 of the smallest diameter and two parts 31 and 32 of larger diameter on each End of part 30, the enlarged part being located between part 30 and a terminating member 33, by which one end of the bore is closed, and the enlarged part 31 between the Bore 30 and a tubular closure body 34, which in the end member 33 facing away from the end of the Hole is screwed in. The outlet 27 opens into the enlarged bore part 32 directly in each bar shaft to the junction with the bore 30, the inlet 29 opens into the widened lead-in part 32 in the vicinity of the terminating element 33.

A cup-shaped member 35 is press-fitted into the enlarged bore portion 32; its end wall is located is located between the passages 27 and 29 and has an opening therein, the edge of which is designed in this way is that 3ie can receive a valve ball 36 which is pressed by a spring 37 into this seat which at its other end rests against the end member 33. The ball 36 therefore seals when it is in the seat, the connection between the inlet 29 and the outlet 27 and becomes loaded in the closing direction with your pressure in the entrance 29.

The tubular Absehlu3körper 34 has on one The end near the bore part 30 has a narrowed passage 38, the outer edge of which is used as a seat for a

Valve ball 39 is formed, which is pressed by a spring 40 in this seat, the spring with the other end of a shoulder rests in the bore of the valve body. The inlet 28 opens into the enlarged Bore part 31 in the immediate vicinity of its connection with the bore part 30, and the outlet 26 opens into an annular space 41 between the wall of the bore in the "valve body and the tubular Closing body 34, the annular space with the bore of the closing body through radial openings

42 is connected, which is in this hole on the from, Part 30 facing away from the constriction 38 open out, The valve ball 39, when it is in the seat, therefore closes the connection between the inlet 28 and the outlet 26, wherein the ball 39 by the liquid pressure at the inlet 28 in the closing direction is pressed.

On the side of the constriction 38 opposite the ball 39, the tubular closing body 34 is a Bore 43, which has the same diameter as the bore part 30. In the bore parts

43 and 30, plungers 44 and 45, respectively, are arranged} the

The plunger 44 carries a pin 46 which is designed in this way

is that it passes through the constriction 38 of the valve ball 39 rests, while the plunger 45 with a pin 47 at one end of the valve ball 39 and with a conical end part 48 rests on the other end of the valve ball 36. The movement of the two The plunger 44 and 45 in the direction of the end member 33 is limited by flanges attached to it, which come into engagement in the relevant bore parts with shoulders 49 or 51, in such a way that

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that when the flanges are in engagement with the switches are located, the yentil balls are lifted out of their seats by the tappets.

The tappets 44 and 45 and the valve balls 36 and 39 are displaced against the end member 33 by a push rod 52 acting on the plunger 44, wherein the push rod 52 is pressed by a helical compression spring 53 against the plunger 44, which on a The end of an annular disk 54 rests, which is held in a spring housing by means of a clamping ring 55,

™ that is formed in one piece with the valve body 25 is, At its other end the spring lies on the yentill body on the side facing away from the end member 53. The push rod 52 is located after installation of the shut-off device in a vehicle under the action of spring means, the pressure of which changes with the load of the vehicle changes and the load by the spring 53 is opposite. 2 B. can the valve body 25 to be attached to the vehicle body, and a lever 57 (Fig. 1), which at one end is hinged to the body, is connected to the push rod 52 at a middle point of its length.

fe bound and at its other end with a tension spring 58, which is anchored on the axle of the vehicle, which carries the wheels with the brakes 13 and is supported by a leaf spring 59. The arrangement is such that the tension of the spring 58 increases when the vehicle load decreases, as a result of which the total spring loading of the tappets 44 and 45 is reduced ₀

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It results daraas that an existing at the outlet 26 Pressure acts on the plunger 44 in such a way that it is displaced in a direction that is the Virkrichtung the spring 53 is opposite, and that an existing pressure at the outlet 27 the plunger seeks to move into the same sighting. As long as the load by the spring 53 is sufficient to To overcome pressures just described, the valve balls 36 and 39 are spaced apart by means of the tappets held by their surfaces.

In the event that the pressures in the two pressure medium pressure arrangements are equal, the pressures acting on the plunger 45 in opposite directions are lifted in their effect on and only the pressure acting on the plunger 44 is that exerted by the spring 53 Load counter to »When the brakes are applied, the connections between the two Pressure sources and the engine cylinders that apply the brakes remain open until the one hits the tappet acting pressure reaches such a value that the load by the spring 53 is thereby overcome will. Then the plunger moves away from the end member 33 until the ball 39 rests on its seat and the connection between the passages 28 and 28 interrupts. The plunger 45 is the movement of the plunger 44, which takes place under the action of the spring 37, follow, so that in a similar manner the Connection between the passages 29 and 27 is interrupted by the valve ball 36 in its Seat. The pressure at which the two balls rest on their respective contact surfaces depends

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depends on the vehicle load, since the force exerted by the spring 53 depends on the force exerted by the spring 58 Train depended

Palis the pressure medium pressure source connected to the inlet 28 is connected, fails, there is no fluid pressure in the space between the two tappets 44 and 45, Therefore, in this case, the plunger 45 will no longer be in pressure equilibrium, but will be under the fluid pressure that prevails at its end adjacent to the end member 33, which is opposite to the action of the spring 53. The valve therefore determines that in the engine cylinders or the pressure acting on the engine cylinder connected to the outlet 27, namely in exactly the same way as it would if the pressure from both pressure medium pressure sources is available. On the other hand, if the pressure source connected to inlet 29 fails, the plunger 44 is still under the pressure of the pressure medium pressure source connected to the inlet 28, namely at its end adjacent to the plunger 45, so that the pressure in the engine cylinder or in the Engine cylinders which are connected to the outlet 26 is effective.

The opening in the end wall of the cup-shaped member 33 has a diameter that is at least is the same size as that of the tappets 44 and 45, so that the pressure of the inlet 29 is applied The area of the ball 36, when this ball is in its seat, is at least as large as that Surface of the plunger 45 on which the in the inlet 28

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prevailing pressure acts, which tends to lift the ball 36 from its seat, so that the ball 36 through the at the inlet 29 prevailing pressure is forced into their seat.

The device described above can, apart from the fluid brakes, those specifically described here Art can also be used in other brake systems that use air or another gas as a pressure medium

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Claims (1)

Λ2, Claims jerk-actuated braking device for vehicles in which the maximum braking force is at least one Pair of wheels can be controlled by a shut-off device which is dependent on the vehicle load and in which the Braking of said wheels of two separate pressure medium pressure arrangements with one at the same time can be actuated on both jointly acting control devices, characterized in that the Shut-off device (24) pressure medium passages (52j 31, 41 »42) for transferring the pressure medium pressure of the each pressure medium pressure arrangement (18, 19) on the associated brakes (H, 15) that the Pressure medium passages with separate closure members (36, 39) are provided that the Closure members by means of a joint acting on both, dependent on the vehicle load and the spring (53) directed in the opposite direction to the pressure medium pressure acting on the brakes in the open position Position are held, and that the brakes even if one of the pressure medium pressure arrangements fails from the other pressure medium pressure arrangement with the entire braking pressure effective against the spring pressure can be charged " 2 »Device according to claim 1, characterized in that that the separate closure members (36, 39) each one axially at a distance from the other, in contact surface arranged in a bore,. that the first closure member (39) has a first The plunger (44) and the second locking member (36) via a second one arranged between the locking members Plunger (45) with common spring (53) 109835/1120 in ¥ ¥ ¥ ¥ ¥ ¥ ular connection is that the plunger with the same large effective areas are formed that the downstream surfaces of the closure members and the two plungers are acted upon by a pressure medium pressure that is opposite to the spring pressure, and that the upstream surface of the first closure member and the first plunger with one the pressure medium pressure rectified to the spring pressure is applied. ο Device according to claim 2, characterized in that that the seat of the second closure member (36) as an opening with at least one of the plunger la before the same passage cross section is formed. 4e device according to claim 2 or 3, characterized in that that stops (47, 49) to limit the axial, opening displacement of the plunger (44 »45) . are provided. ο Device according to claim 1, characterized in that that the shut-off element (24) is arranged on the body of the vehicle equipped with the brakes is that a connecting member (57) between a stop (54) of the common spring (53) and a vehicle axle with a spring that counteracts the force as the vehicle load increases decreasing effective spring (58) is provided «, 109835/1120