SE434246B - BRAKE VALVE FOR A TWO-SHORT BRAKE SYSTEM - Google Patents

Description

i? sousv2-2- To eliminate this problem, the known brake valve has enabled load-dependent actuation of the front axle brake pressure without additional control valve for the front axle brake circuit by providing the second single valve in the brake valve with different load-dependent influences with different intermediate rings, which are insertable into the valve housing. However, this entails the disadvantage that extra manufacturing and storage of these intermediate rings is necessary.

Advantages of the invention.

The two-circuit brake valve with the features specified in the patent claim 1 has the advantage that only one commercially available O-ring needs to be replaced at any one time.

Apart from the fact that such O-rings are available in every major workshop, it is also very economical from the brake manufacturer's point of view that different regulatory conditions can be achieved in this simple way.

As required, all steps on the step piston can be finished or only the normally required ones can be prepared in this way.

Drawing An embodiment of the invention is described in more detail below with reference to the accompanying drawing, which shows a two-circuit brake valve in axial section.

Description of the invention A two-circuit brake valve has a housing 1, in which a control rod 2 is inserted from above. The rod 2 presses on a sleeve 3 with a ring shoulder 4, under which a valve spring travel path 5 extending the valve operating distance is arranged. The other end of the road spring 5 rests against a deflection and rebound piston 6, which at its other end carries an inlet valve seat 7 of a first single valve 8. A second valve seat 9 of the single valve 8 is located on a part 17 'of one of two parts consisting. wave piston l7. The side of the piston part 17 'facing the piston 6 delimits a pressure gear chamber 10. A storage chamber 11 is formed between a piston wall and a guide body. This is connected via a threaded connection to a supply line to a rear axle brake circuit I, with brake cylinders (not shown), which are connected to the supply via the pressure gear chamber 10 and a threaded connection. A valve element 13 cooperates the two valve seats 7 and 9 and is pressed against it by a valve spring 12. The other end of the spring 12 rests against an inner ring shoulder 14 of the piston 6. Against this inner ring shoulder 14 also rests a return spring 18, which is protected against bending of a guide pin 35 attached to the wave piston part 17 '.

With its second wave piston part 17 ", the wave piston 17 defines a pressure gear chamber 26 for the brake circuit II. At this point, the wave piston part 17" has an outlet valve seat 22 intended for a second single valve 19, which is similar to the outlet valve seat 9.

The weighing piston 17 has the same working surfaces upwards and downwards, apart from a load-dependent impact described in more detail below.

Within the two outlet valve seats 9 and 22, the weighing piston 17 is provided with axial openings 21. At its circumference the weighing piston 17 carries two O-rings 24 and 25 and the space between these O-rings is connected to the bore 21. at the outlet valve seat 22 there is a housing fixed inlet valve seat 23 of the second single valve 19.

The inlet seat 23 lies between the pressure gear chamber 26 and a storage chamber 27, in which a valve element 28 of the second single valve 19 for the brake circuit II is arranged.

The housing 1 is closed downwards by means of an insert wall 1 '. Against this rests both a valve spring 29 of the second single valve 19 and a wave piston 30 acting on the wave piston 17.

The wall 1 'carries a guide body, on which the valve element 28 is axially movably arranged with a ring sealing lip.

The valve element 13 of the first single valve 8 and the valve element 29 of the second single valve 19 are mutually equal and are axially pierced for pressure relief. Via these bores in the valve elements and via an atmospheric air connection 31, a common connection is established between the two single valves 8 and 19 to the atmosphere.

The two guide bodies are the same as well as the two valve elements 13 and 28 sliding thereon and the valve springs 12 and 29. The return spring 18 and the advance spring 790lr972-2 F _ 3 30 are arranged within the equally large valve springs 12 and 29.

The weighing piston part 17 'is designed as a step piston with three steps a, b and c. Matching steps a', b 'and c' are arranged in the housing 1. In one of the steps a, b and c an O-ring 36 potted; in the embodiment shown, this step b is formed. In this way, between the O-ring 36 and the O-ring 24 arranged at the piston diameter, an annular chamber 37 is formed, which is connected via a threaded connection 38 to an automatic load-dependent unit (not shown). giver.

Function When the brakes are released, the valve elements 13 and 28 are lifted from the two outlet valve seats 9 and 22 and the brake circuits I and II are vented via the common atmospheric air connection 31.

During braking, the control rod 2 runs into the brake valve and, while depressing the road spring 5, engages the deflection and rebound piston 6. With the piston 6, the inlet valve seat 7 also moves downwards and allows the valve element 13 to be mounted against the outlet valve seat 9. The first single valve 8 - valve is thus closed and its inlet valve opens. The pressure in the pressure gear chamber 10 then means that the force of the advance spring 30 is overcome, after which the second single valve 19 in the brake circuit II is also switched. With the load-dependent influence via the threaded connection 38, it can now be achieved that, depending on the use of an O-ring in step a, b or c, a load ratio of 2.7: 1 or 2: 1 or 1.5: 1 can be adjusted in front axle brake circuit II.

If the ratio is desired to change, only the 0-ring 36 needs to be replaced with a larger or smaller 0-ring.

Claims (4)

7904972-2 Patent claim r 1. l. Two-circuit brake valve for a compressed air braking system of motor vehicles, with two single valves (1) arranged one after the other in a valve housing (1), and a control rod (2), which pushes into the valve housing (1 ) and in this, via a valve operating distance extending the road spring (5) cooperates with a piston (6) with a valve part (7) for the first single valve (8), partly a device (17 ") for actuating the second single valve (19), and on the one hand a load-dependent guide (17 ') affecting the function of this device, characterized in that the load-dependent guide is formed by a stepping piston (17') made in several steps, which is movable in a similarly stepped bore in the housing (1), and that the step piston (17 '), due to various load-dependent effects of the coupling work of the two-circuit brake valve, is sealable against the step bore at one of its steps (a, b, c). Valve according to claim 1, characterized in that the step piston (17 ') has two or more, preferably three steps (a, b, c), of which only one is provided with a ring seal (36), preferably with a 0-ring seal for sealing the step piston. Valve according to Claim 1 or 2, characterized in that the step piston (17 ') carries an outlet valve seat (9) of the first single valve (8) and with its large diameter abuts against and is jointly movable with a piston part. (17 '), which carries an outlet valve seat (22) of the second single valve (19). Valve according to claim 3, characterized in that the two piston parts (17 'and 17 ") together form a road piston (17), which is arranged between a pressure gear chamber (10) of a first brake circuit (I) and a pressure gear chamber ( 26) of a second brake circuit (II)