GB2129078A

GB2129078A - Brake master cylinder reservoir

Info

Publication number: GB2129078A
Application number: GB08322834A
Authority: GB
Inventors: Hans-Dieter Reinartz; Waldemar Vatter
Original assignee: Alfred Teves GmbH
Current assignee: Continental Teves AG and Co oHG
Priority date: 1982-10-20
Filing date: 1983-08-25
Publication date: 1984-05-10
Also published as: GB8322834D0; GB2129078B

Abstract

A mouldable compensating reservoir (1) for a hydraulic brake system, in particular for the brake system of an automotive vehicle, is provided with two interconnected brake fluid chambers (2, 3) which are each in communication with a port (8, 9) for connection to a respective pressure chamber of a tandem master cylinder. To enable manufacture of such a compensating reservoir by a single injection moulding process, there is provided a tube (12) which extends transversely to the reservoir's vertical axis and which projects from one of the brake fluid chambers (2, 3), the projecting end being adapted to be closed. One of the ports may be branched-off the tube 12 (Fig. 3). <IMAGE>

Description

SPECIFICATION Mouldable compensating reservoir The present invention relates to a mouldable compensating reservoir for a hydraulic brake system, in particular for the brake system of an automotive vehicle, of the kind having two interconnected brake fluid chambers which are each in communication with a port to connect to a respective pressure chamber of a tandem master brake cylinder.

A compensating reservoir of this kind is known from British patent specification 1,548,669. This reservoir comprises two brake fluid chambers arranged at a distance side by side and interconnected by an intermediate chamber disposed between them. The intermediate chamber contains a float of a fluid level indicator.

Each of the brake fluid chambers is closed at its top by a separate cap and has at its bottom a port extending in parallel to the vertical axis of the reservoir. Due to its complicated design, this known reservoir entails great and costly efforts in manufacture, since it cannot be made by injection moulding. Besides, this reservoir requires a relatively large mounting space.

There are previously also known mouidable compensating reservoirs which allow of manufacture by injection moulding. These mouldable compensating reservoirs, however, are likewise relatively complicated in their design and contain several undercuts. Therefore, the lower part and the upper part will be injection-moulded separately during manufacture and will subsequently be welded together. Consequently, this procedure necessitates relatively great effort, since the casting machine will be occupied twice and a welding process will also be needed afterwards.

It is therefore an object of the present invention to provide a mouldable compensating reservoir of the kind initially referred to which can be manufactured in a single injection moulding process.

According to the invention in its broadest aspect, a mouldable compensating reservoir of the kind referred to is characterised in that a tube extending transversely to the reservoir's vertical axis projects out of one of the brake fluid chambers, the projecting end of the tube being adapted to be closed.

Thus, a mouldable compensating reservoir will be provided which is of very straightforward design and can be manufactured by a casting machine in a single injection moulding process. In this arrangement, the removal of the core is effected through the tube that extends transversely to the reservoir's vertical axis. A clutch hose can be connected to the tube, in addition. Closing of the tube will be carried out simply by squashing and welding it.

According to an advantageous embodiment of the invention, a connecting tube which extends transversely to the reservoir's vertical axis is provided for interconnection of the brake fluid chambers, the tube being disposed on the same axis as the projecting tube. With this design, the removal of the core from the mould can be done in a simple way in a single operation. According to another favourable embodiment, the tube extending transversely to the reservoir's vertical axis comprises the master cylinder port of the corresponding chamber.In a, spatially, particularly economical arrangement having a central float chamber connected to the brake fluid chambers, it is provided that the compensating reservoir comprising the three chambers has a substantially cylindrical shape and that the brake fluid chambers are established by at least one radial partition wall arranged in the compensating reservoir. Suitably, the float chamber is at the same time of substantially cylindrical design and is placed concentrically in the reservoir. This ensures in a, spatially, extremely economical manner the positioning of the float in that area of the compensating reservoir in which there occur the slightest level variations in the event of inclination, acceleration or slowing down of the vehicle.

In another embodiment of the present invention, the float chamber contains at its periphery two bulged-out portions, elongated in cross-section, which each project into a brake fluid chamber and comprise openings connecting the brake fluid chamber to the float chamber.

To delay the occurrence of fluid level variations in the event of inclination, acceleration or slowing down of the vehicle, it will be expedient for a brake fluid chamber having one port to be provided with a wall which latter, starting from the wall of the float chamber, encloses partially the bore arranged in the bottom of the chamber and extends substantially vertically to the bottom.

To achieve stabilisation of the tube which projects out of the reservoir, there will be suitably provided a reinforcing element coupling the tube to the reservoir's outer wall.

In a very favourable variant, the two brake fluid chambers are closed by a joint cap which will be screw-threaded for this purpose.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a partial cross-sectional side view of a mouldable compensating reservoir having brake fluid chambers arranged side by side, Fig. 2 is a top view of the compensating reservoir of Fig. 1 in partial cross-section, Fig. 3 is a partial cross-sectional side view of a mouldable compensating reservoir with float chamber, wherein the reservoir comprising the brake fluid chamber and the float chamber is of substantially cylindrical shape, Fig. 4 is a partial cross-sectional top view of the compensating reservoir of Fig. 3, Fig. 5 is a partial cross-sectional side view of another embodiment of a cylindrical reservoir containing two brake fluid chambers, and Fig. 6 is a top view of the compensating reservoir of Fig. 5 in partial cross-section.

Figs. 1 and 2 illustrate a compensating reservoir 1 having two brake fluid chambers 2, 3 arranged side by side. The brake fluid chambers are of substantially cylindrical design. They are closed by a bottom 4, 5, while they have threaded caps 6, 7 on top. At the bottom 4, 5 of each brake fluid chamber 2, 3, there is provided a port 8, 9 which extends in parallel to the reservoir's vertical axis and which is connectible to corresponding ports of a tandem master brake cylinder (not shown). The brake fluid chamber 2 contains, inside, a float 10 of a brake fluid level gauge.

The brake fluid chambers 2, 3 are interconnected via a connecting tube 11 which extends transversely to the reservoir's vertical axis.

This ensures level compensation. A tube 12 projects radially out of the brake fluid chamber 2, the axes of the connecting tube 11 and of the tube 12 being disposed on one line. In this arrangement, the core (not shown) forming the connecting tube 11 can be drawn out easily through the tube 12 when manufacturing by injection moulding. After the removal of the core, the projecting end of the tube 1 2 will be closed, in particular welded. In case of need, the end can be cut open, for instance, for the purpose of connecting a clutch hose.

The compensating reservoir 1 6 illustrated in Figs. 3 and 4 is of substantially cylindrical shape, with brake fluid chambers 1 7 and 1 8 and a float chamber 19 being formed within the compensating reservoir 1 6. The float chamber 1 9 is likewise of substantially cylindrical shape and is arranged concentrically in relation to the reservoir's outer wall 20. The float chamber 1 9 comprises, inside, a float 21.The substantially circular cylindrical wall 22 of the float chamber has two bulged-out portions 23, 24, elongated in cross-section, which each project into one of the brake fluid chambers 17, 1 8 and which are provided at their ends with openings 25, 26 which connect the brake fluid chambers 1 7, 1 8 with the float chamber 19. By virtue of the bulged-out portions 23, 24, labyrinths will be formed in the interior of the reservoir which delay level variations in the event of inclinations, decelerations and accelerations of the vehicle.

The brake fluid chambers 17, 18 are constituted by walls 27, 28 which extend from the wall 22 of the float chamber 1 9 radially outwardly to the reservoir's outer wall 20.

Projecting into the brake fluid chamber 1 7 is a tube 29 whose end 30 extends through the reservoir's outer wall 20 out of the compensating reservoir 1 6. The tube 29 extends transversely to the reservoir's vertical axis and is arranged on the bottom 31 of the reservoir in a tangentially radially extending fashion in the application illustrated. The projecting end 30 of the tube 29 comprises a port 32 extending in parallel to the reservoir's vertical axis and is closed at its end.

This closing can be effected in the same way as in the embodiment of Figs. 1 and 2. A reinforcing element 33 extends between the reservoir's outer wall 20 and the outer portion of the tube 29. The brake fluid chamber 1 8 contains in its bottom 31 an opening 34 with a second paraxial port 35. The opening 34 is, within the brake fluid chamber 18, encompassed by a wall 36 which, starting from the wall 22 of the float chamber 19, encloses the opening partially and which extends substantially perpendicular to the bottom 31. This wall 36 forms another labyrinth for the brake fluid.

On top, the compensating reservoir 1 6 is closed by means of a single threaded cap 37 covering all three chambers 17, 18 and 1 9. The threaded cap 37 comprises an internal thread 38 which can be screwed to an external thread 39 which is provided at the upper edge of the reservoir's outer wall 20.

The compensating reservoir 43 illustrated in Figs. 5 and 6 is, in its outward appearance, similar to the compensating reservoir 1 6. Like the latter, it is of substantially cylindrical design and contains two brake fluid chambers 44, 45. These brake fluid chambers 44, 45 are constituted by a diagonally extending wall 46 which extends from the bottom 47 of the reservoir paraxially to the top, however, not as far as the reservoir's outer wall 48. In the bottom 47, there are provided openings 49, 50 with ports 51, 52 in each chamber. A radially extending tube 53 is arranged at the reservoir's outer wall 48 at an acute angle in relation to the reservoir's vertical axis and terminates through an opening 54 in the reservoir's outer wall 48 into the brake fluid chamber 44. The end of the tube 53 is closed, as shown for instance in Figs. 1 to 4, and can be opened for the purpose of connecting a clutch hose. The compensating reservoir 43 is closed by means of a threaded cap 55.

Claims

1. A mouldable compensating reservoir for a hydraulic brake system, in particular for the brake system of an automotive vehicle, of the kind having two interconnected brake fluid chambers which are each in communication with a port to connect to a respective pressure chamber of a tandem master brake cylinder, characterised in that a tube (12; 29; 53) extending transversely to the reservoir's vertical axis projects out of one of the brake fluid chambers (2,3; 17, 18; 44,45), the projecting end of the tube being adapted to be closed.

2. A mouldable compensating reservoir as claimed in claim 1, characterised in that a connecting tube (11) extending transversely to the reservoir's vertical axis is provided for interconnection of the brake fluid chambers (2,3; 1 7, 1 9; 44, 45), and in that the projecting tube (12) and the connecting tube (11) are disposed on the same axis.

3. A mouldable compensating reservoir as claimed in claim 1, characterised in that the projecting tube (29) contains one of the ports (32).

4. A mouldable compensating reservoir as claimed in claim 1, with a central float chamber communicating with the braked fluid chambers, characterised in that the compensating reservoir (16) comprising the three chambers (17, 18, 19) is of substantially cylindrical shape, and in that the brake fluid chambers (1 7, 18) are constitued by at least one radial partition wall (27, 28) arranged in the compensating reservoir (16).

5. A mouldable compensating reservoir as claimed in claim 4, characterised in that the float chamber (1 9) is of substantially cylindrical design and is arranged concentrically in the compensating reservoir (16).

6. A mouldable compensating reservoir as claimed in claim 4 or 5, characterised in that the float chamber (19) has at its periphery two bulged-out portions (23, 24), elongated in crosssection which each project into a brake fluid chamber (17, 18) and contain openings (25, 26) connecting the brake fluid chambers (17, 18) to the float chamber (1 9).

7. A mouldable compensating reservoir as claimed in any one of the preceding claims, with at least one of the brake fluid chambers having in its bottom an opening which represents the port, characterised in that, in the brake fluid chamber (18) containing the port, a wall (36) is provided which, starting from the wall (22) of the float chamber (19), partially encloses the opening (34) in the bottom (31) and which extends substantially perpendicular to the bottom.

8. A mouldable compensating reservoir as claimed in any one of the preceding claims, characterised in that there is provided a reinforcing element (33) which interconnects the reservoir's outer wall (20) and the tube (29) projecting from the reservoir.

9. A mouldable compensating reservoir as claimed in any one of claims 1, 3, 4, 5 or 6, characterised in that both brake fluid chambers (17, 18; 44,45) are closed by a joint cap (37; 55).

10. A mouldable compensating reservoir as claimed in claim 8, characterised in that the joint cap (37; 55) comprises a screw thread.

11. A mouldable compensating reservoir substantially as described with reference to the accompanying drawings.