FR2466376A1 - Multi-circuit brake protection valve - has single non-return valve fitted between two sets of circuits - Google Patents

Abstract

The multi circuit brake protection valve has a single non return valve (8) separating two sets of circuits (I,II and III,IV), and each brake circuit has a separate flow control valve (2,3,4,5). In the event of circuit failure only one group of circuits is isolated and the remainder may continue to function. The non return valve and the flow control valves are mounted in a single housing, with the non return valve having a central bore through the housing. A simple, low cost control system is obtained.

Description

The present invention relates to a protection valve for several circuits, for brake systems of motor vehicles, the housing of which contains a relief valve for each circuit. A protection valve of this type is known (patent application available to the public of the
Federal Republic of Germany no 24 23 520).

 In such protective valves, on the one hand, the manufacture of the channels and holes in the housing is difficult, because almost all of them must be carried out in particular working phases or with particular tightening of the housing, on the other hand , for a filling of the same order of all the circuits, in the event of a breakdown of a service brake circuit, the other circuits can only be protected by non-return valves, a special non-return valve being necessary for each circuit.

 The protection valve of the invention is characterized in that it is provided with a central passage, and in that there exists in this passage a check valve which protects part of the brake circuits with respect to the other part. This valve thus has the advantage that circuits of the same order can be assembled in groups which are protected from each other.

In the event of a service brake circuit failure, the central check valve prevents a pressure drop in the auxiliary consumer circuits. To protect multiple consumers from service brake circuits, a single check valve is sufficient.

Other characteristics and advantages of the invention will be better understood on reading the following description of an exemplary embodiment and with reference to the appended drawings in which
- Figure 1 shows a diagram of the protection valve for four circuits; and
- Figure 2 shows a section through the housing of a protection valve for four circuits.

 A protection valve 1 for four circuits has a schematic arrangement in the form of four relief valves 2, 3, 4, 5 supplied in the same order and which can all be reached by a central passage 7 from a connection inlet 6. Downstream of the valves 2, 3, 4, 5, four brake circuits I, II, III, IV were connected, circuits I and II being service brake circuits and circuits III and IV being the auxiliary consumer brake circuits.

 In the central passage 7, a check valve 8 has been placed behind a branch 15 for the valves 2 and 3 associated with the two service circuits I and II. The valve 8 is located in front of a bypass 16 for the two auxiliary consumers III and IV. With the aid of this check valve 8, the two auxiliary consumers III and IV are protected from the service brake circuits I and II, so that in the event of a brake circuit I or II failure the consumers III and IV are not affected so there is no pressure drop in circuits III and IV. It is important that these two circuits III and IV are protected only by a single common check valve 8.

 FIG. 2 represents a section through the casing 9 of a protection valve for four circuits. Note the inlet connection 6, the central passage 7 and the check valve 8.

Four crankcase outlets, downstream of the relief valves not shown 2, 3, 4 and 5, bear the marks 10, 11, 12 and 13.

 Of course, various modifications can be made by those skilled in the art to the devices or methods which come from described only by way of nonlimiting examples without departing from the scope of the invention.

Claims (3)

1. Protection valve for several circuits, for motor vehicle brake systems, the casing of which contains a relief valve for each circuit, characterized in that it is provided with a central passage (7), and in that 'there is in this passage (7) a check valve (8) which protects a part (III, IV) of the brake circuits (I, II, III, IV) with respect to the other part (I, II). 2. Valve according to claim 1, to protect at least one auxiliary consumer of two service brake circuits, characterized in that the check valve (8) is provided behind a bypass (15) for the two relief valves (2 , 3) associated with the two service brake circuits (I, II). 3. Valve according to any one of claims 1 or 2, in the form of a protection valve for four circuits, characterized in that the check valve (8) is provided in front of a bypass (16) for two auxiliary consumers (III, IV).