GB2115528A

GB2115528A - Brake fluid reservoir cap

Info

Publication number: GB2115528A
Application number: GB08303580A
Authority: GB
Inventors: Hans-Dieter Reinartz; Waldemar Vatter
Original assignee: Alfred Teves GmbH
Current assignee: Continental Teves AG and Co OHG
Priority date: 1982-02-24
Filing date: 1983-02-09
Publication date: 1983-09-07
Also published as: FR2521934B1; GB8303580D0; DE3206520C2; FR2521934A1; DE3206520A1; GB2115528B

Abstract

A valve arrangement for a compensating reservoir in a hydraulic brake system with a threaded cover (4) encompassing the filling opening (3) of a filling socket (1) has an inlet channel (7), and an outlet channel (8) sealable by an inlet valve and an outlet valve having a common elastic valve ring (11), which forms the valve element, and also the gasket between the front surface (10) of the fill socket (1) and the threaded cover (4). The inlet channel (7) and the outlet channel (8) are separate channels arranged in the threaded cover (4), partially bridging the valve ring (11). For the formation of the inlet valve the valve ring forms by means of one of its edges a sealing lip (12) locking the inlet channel (7) and opening it in the inlet direction. For the formation of the outlet valve the valve ring (11) forms by means of its other edge a sealing lip (13) locking the outlet channel (8) and opening it in the outlet direction. <IMAGE>

Description

SPECIFICATION Brake system This invention relates to a hydraulic brake system and particularly to a valve arrangement for a compensating reservoir in such a system, of the kind in which the compensating reservoir has a filling socket and a threaded cover which encompasses the filling opening of the socket on the outside, with at least one inlet channel and one outlet channel which are sealable by means of an inlet valve and an outlet valve having a common elastic valve ring forming a valve element and with a gasket arranged between the front surface of the filling socket and the threaded cover.

Such a valve arrangement is known from German Printed Patent Application (DE-AS) No.

25 01 228. In this arrangement, the gasket provided between the front surface of the filling socket and the thread completely seals the filling socket at this spot. An axial bore provided in the top side of the threaded cover forms an inlet-andoutlet channel. For the purpose of forming an inlet-and-outlet valve the threaded cover has a pin at its centre and an annular rib which is coaxial in respect of the rib, the rib and the pin both projecting into the reservoir. The pin has a groove into which a locking washer is inserted, forming an annular shoulder and being so arranged relative to the free end of the rib that a baffle of elastomeric material acting as an elastic valve ring is deformed in an elastic manner so as to form a ball segment whose concave side is turned inwards The circumference of the convex surface normally, i.e.

under balanced pressure conditions, rests at the rib sealingly with regard to the fluid medium, whereas the inside edge of the valve ring encompasses the pin, the centre part of the concave surface of the valve ring being pressed on to the annular shoulder of the locking washer in an elastic and sealing manner with regard to the fluid medium. The pressure in the reservoir dropping, the valve ring will slightly bend at its outside periphery so as to allow a sufficient amount of air to enter the compensating reservoir. In the event of excessive pressure in the compensating reservoir the centre part of the valve ring will lift so as to allow the air to flow back into the atmosphere.The known arrangement already prevents the unhindered flow of outside air into the brake-fluid-filled reservoir in the rest position of the brake so that the highly hygroscopic brake fluid will take up water from the outside air only if, due to the braking action, via the valve outside air will be sucked into the reservoir. Further, this arrangement ensures that excess air caused by respectively the release of the brake or variations in temperature due to changes in the volume of the brake fluid may escape from the reservoir. In the known arrangement, in addition to the gasket at the front surface of the filling socket at least one further component is required, i.e. the baffle forming the elastic valve ring.

It is the thus an object of this invention to improve a valve arrangement of the type referred to above in that no further components are needed besides the component forming the seal.

According to this invention in its broadest aspect a valve arrangement of the kind referred to is characterised in that the valve ring is the gasket, in that the inlet channel and the outlet channel are separate channels arranged in the threaded cover, partially bridging the valve ring, in that for the formation of the inlet valve the valve ring by means of one of its edges forms a sealing lip which rests at the inside of the cover, locking the inlet channel and opening it in the inlet direction, and in that for the formation of the outlet valve the valve ring by means of its other edge forms a sealing lip which rests at the inside of the cover, locking the outlet channel and opening it in the outlet direction.

Thus a valve arrangement is provided which is marked by great constructional simplicity, which in particular will not need any additional parts besides the gasket, and which is thus extremely cost-saving.

From German Laid-open Patent Application (DE-OS) No. 25 58 824 a compensating reservoir is known where just one gasket is arranged in the threaded cover, this gasket being bridged by grooves formed in the threaded cover and forming inlet and outlet channels. The gasket is, however, completely bridged and thus does not perform any valve function. This means that the inlet and outlet channels are constantly open. Thus the outside air may permanently enter the inside of the reservoir even if the brake is not applied.

In order to provide a particularly expedient and simple arrangement of the inlet and outlet channels, the sealing lip of the valve ring forming the inlet valve is provided at the inner edge of the valve ring and the sealing lip forming the outlet valve is provided at the outer edge of the valve ring.

So as to prevent the inlet and outlet channels from becoming contaminated and the accumulation of water which might be sucked into the reservoir upon braking further embodiments of this invention provide that the inlet and outlet channels are partially led along a clearance within the threads of the cover. In these embodiments the water will be collected in a spot whence it may flow back to the outside without any further difficulties.

A further advantageous embodiment of this invention provides that a disk is axially arranged at a distance with regard to the valve ring and that it has axial through openings. This disk will prevent the seal from falling out while at the same time, via its bores, it will form part of the inlet and outlet channels.

For the formation of the required sealing lips the cross-section of the valve ring expediently has the shape of an anvil.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 shows the cross-section of partial view of a filling socket of a compensating reservoir (not shown) for hydraulic brake systems with a threaded cover and a valve arrangement and Fig. 2 shows another embodiment of the valve arrangement of the filling socket according to Fig. 1.

The filling socket 1 represented in Fig. 1 and belonging to a compensating reservoir has an outside thread 2 at its upper part. Onto the outside thread 2 is screwed a threaded cover 4 which encompasses a filling opening 3 and which has a corresponding inside thread 5. The threads 2 and 5 are so designed as to ensure a clearance 6 within the screw thread along the pitch. On one side of the threaded cover 4, an inlet channel 7 ends in this clearance 6 and on the other side an outlet channel 8 ends there, these channels being formed in the cover surface. Thus an air connection is established between the surrounding atmosphere and the interior space 9 of the filling socket 1 via the clearance 6 and the inlet channel 7 and the outlet channel 8, respectively.

A ring 11 of elastic materiai such as rubber or the like lies on the front surface 10 of the filling socket. The ring 11 has a double function. It forms a seal along the major part of the periphery of the front surface 10. In the area of the inlet channel 7 and of the outlet channel 8 the ring 11 at the same time forms an inlet valve and an outlet valve, respectively. For this purpose, the inlet channel is formed in the threaded cover 4 in such a way as to bridge the ring 11 essentially. However, the inlet channel 7 does not pass entirely up to the inside edge of the ring 11. Thus the ring 11 rests with its inside edge at a shoulder 7a forming the end of the inlet channel 7 at the inside of the threaded cover 4 and in this way locks the inlet channel 7 at this point.As the ring 11 in this area does not rest on the front surface 10 it is here relatively freely movable downwards in an axial manner so as to form a movable inlet valve element in the form of a sealing lip 12.

The outlet channel 8 in the threaded cover 4 is passed inwards beyond the inside edge of the ring 1 Thus, together with the ring 11, it forms a permanently open annular cap. Outwards, the outlet channel 8 ends before the outside edge of the ring 11. The ring 11 thus forms in this area an outlet valve element in the form of a sealing lip 1 3 which rests at a shoulder 8a forming the end of the outlet channel 8 at the inside of the threaded cover 4. In order to permit an axial movement of the ring 11 in this area a recess or bevel 14, respectively, is provided here.

Inside the threaded cover 4 a central pin 1 5 is provided which has an enlarged portion 16 at its end, a disk 1 7 lying on the enlarged portion 1 6.

The disk 17 is axially arranged at a distance in respect of the ring 11 and has a number of axial bores 18, 19. On the one hand, this disk will enable the flowing-in and out of air via the bores 18, 1 9 while it will prevent the ring 11 from falling out when the threaded cover 4 is mounted on the fill socket 1.

The valve arrangement represented in Fig. 2 in principle features the same design as that represented in Fig. 1. In contrast to the arrangement of Fig. 1 in this one the cross-section of the ring 20 corresponding to the ring 11 of Fig.

1 has the shape of an anvil. Thus, at the edges the ring 20 forms sealing lips 21,22 with pointed ends.

In the following the principles of the mode of operation of the valve arrangements will be described. A low pressure in the compensating reservoir will cause the sealing lip 12, 21 in the area of the inlet channel 7 to lift offfrom its stop shoulder 7a at the threaded cover 4 and to form an opening (not shown) through which outside air flowing in via the clearance 6 between the threads 2, 5 may enter the interior space of the reservoir as indicated by arrows. During this action the sealing lip 13, 22 will firmly rest at the stop shoulder 8a, locking the outlet channel 8 at this point. Vice versa, in the event of excessive pressure inside the reservoir the sealing lip 1 3, 22 will be lifted off from the stop shoulder 8a and open the outlet channel 8 at this point. Thus air may escape via the clearance 6 between the threads 2, 5. The sealing lip 12,21 will firmiy rest at the stop shoulder 7a during this action, locking the inlet channel 7 at this point.

Claims

1. A valve arrangement for a compensating reservoir in a hydraulic brake system, of the kind in which the compensating reservoir has a filling socket and a threaded cover which encompasses the filling opening of the socket on the outside, with at least one inlet channel and one outlet channel which are sealable by means of an inlet valve and an outlet valve having a common elastic valve ring forming a valve element and with a gasket arranged between the front surface of the filling socket and the threaded cover, characterised in that the valve ring (11, 20) is the gasket, in that the inlet channel (7) and the outlet channel (8) are separate channels arranged in the threaded cover (4), partiaily bridging the valve ring (11, 20), in that for the formation of the inlet valve ring (11, 20) by means of one of its edges forms a sealing lip (12, 21) which rests at the inside of the cover, locking the inlet channel (7) and opening it in the inlet direction, and in that for the formation of the outlet valve the valve ring (11, 20) by means of its other edge forms a sealing lip (13, 22) which rests at the inside of the cover, locking the outlet channel (8) and opening it in the outlet direction.

2. A valve arrangement according to claim 1, characterised in that the sealing lip (12, 21) of the valve ring (11, 20) forming the inlet valve is provided at the inner edge of the valve ring (11, 20) and in that the sealing lip (13, 22) forming the outlet valve is provided at the outer edge of the valve ring (11,20).

3. A valve arrangement according to any one of the preceding claims, characterised in that the inlet channel (7) ends in a clearance (6) formed between the threads (2, 5).

4. A valve arrangement according to any one of the preceding claims, characterised in that the outlet channel (8) ends in a clearance (6) formed between the threads (2. 5).

5. A valve arrangement according to any one of the preceding claims, in which the threaded cover has a central pin on the inside which carries a disk whose outside diameter exceeds the inside diameter of the valve ring, characterised in that the disk (1 7) is axially arranged at a distance in respect of the valve ring (11, 20) and has axial through openings (18, 19).

6. A valve arrangement according to any one of the preceding claims, characterised in that the cross-section of the valve ring (20) has the shape of an anvil.

7. A valve arrangement for a compensating reservoir in a hydraulic brake system substantially as described with reference to the accompanying drawings.