GB2248094A

GB2248094A - Reservoir for a hydraulic brake system

Info

Publication number: GB2248094A
Application number: GB9119850A
Authority: GB
Inventors: Horst Muller
Original assignee: Alfred Teves GmbH
Current assignee: Continental Teves AG and Co oHG
Priority date: 1990-09-21
Filing date: 1991-09-17
Publication date: 1992-03-25
Anticipated expiration: 2011-09-17
Also published as: FR2667036B1; FR2667036A1; GB9119850D0; DE4029931C2; DE4029931A1; GB2248094B

Abstract

A reservoir of a substantially angular plan configuration for a hydraulic brake system is provided in a corner area with a connection for a clutch generating cylinder in communication with the remainder of the reservoir volume through a bipartite chamber system (4, 5). The first of the chambers (4) in which terminates the connection for the clutch generating cylinder holds, at most one quarter of the volume of the second chamber (5) which is in directly adjoining relationship and in communication therewith, through a first overflow (1). The bottom edge or opening of the overflow (1) is at a level between the minimum and the maximum permitted filling level of the reservoir. The second chamber (5) starts from the first chamber (4) and extends as a narrow channel along a reservoir wall (6) and a portion of another reservoir wall (7) with the end thereof having a second overflow (2) with a lower opening or edge between the minimum and maximum permitted filling level forming a connection to the remainder of the reservoir volume. This arrangement will prevent the reservoir from bleeding in case of a defective condition of connection of the generating cylinder of the clutch below the minimum permitted filling level. <IMAGE>

Description

1 RESERVOIR FOR A HYDRAULIC BRAKE SYSTEM The present invention relates to

a reservoir f or a hydraulic brake system.

More specifically the present invention relates to such a reservoir of the type including a connection f or a generating cylinder of a clutch and serving to release pressure fluid in the event of pad wear.

Reservoirs of the af ore-mentioned type are widely used at present. They have the advantage that excess hydraulic fluid arising as a result of worn clutch linings is re-supplied to the reservoir. However, reservoirs of this type have hitherto involved the risk of complete bleeding if the clutch generating cylinder is damaged and, moreover, an unfavourable angle of inclination due to the road surf ace could result in a lack of hydraulic fluid required for decelerating the automotive vehicle.

An objective to which the present invention is directed resides in attaining a high degree of safety, even with a defective supply conduit leading to the clutch generator cylinder, whilst at the same time preserving the advantage of a reservoir of the afore-mentioned type, in that a bleeding under the minimum permitted f illing level of the reservoir is precluded.

According to one aspect of the invention there is provided a reservoir for a brake system including a connection f or a generating cylinder of a clutch and serving to release pressure f luid in the event of pad wear, the 2 reservoir having a generally rectilinear or angular compartmented construction with the connection for the clutch generating cylinder being located in one angular area of the reservoir, characterised in that the connection for the clutch generating cylinder is in communication with the remainder of the reservoir interior volume through a bipartite chamber system, in that a first chamber of the chamber system and in which the connection for the clutch generator cylinder terminates holds, at best, a quarter of the volume of a second chamber in directly adjoining relationship therewith through a first overflow having a lower opening which is at a level between the minimum and maximum permitted filling levels of the reservoir, and in that the second chamber extends at one end from the first chamber in the form of a narrow channel running along one reservoir wall and a portion of another reservoir wall and at the other end thereof has a second overflow with a lower opening therein located between the minimum and maximum permitted filling levels and forming a connection to the remainder of the reservoir volume.

The principle of the invention resides in providing, through a suitable chamber system, a lock-type or trap means not allowing any fluid to escape or, in extreme situations, only small amounts of fluid at a time, once the supply line leading to the clutch generating cylinder is damaged or broken.

The chamber system of the reservoir comprises at least two chambers of which the first where the connection for the clutch generator cylinder.is terminated, may be of a very small base area since clutch wear does not require any additional brake fluid but rather provides an excess which is supplied to the reservoir.

The first chamber is in communication with the second chamber through an overflow at a level between the maximum and minimum permitted filling level of the reservoir. The second chamber is narrow and elongated so that it extends - starting from the first chamber - along a complete wall and 3 a portion of a further reservoir wall to a point where the fluid level at a permitted filling level changes negligibly once the reservoir is inclined in the plane of the further reservoir wall. At that point, the second chamber has a 5 second overflow into the reservoir interior.

According to a second aspect of the invention the reservoir may be of circular, oval or other curved configuration so that the second chamber may be provided in the circumferential direction. The two overflows, selectively, may be provided as slots from the overflow level to the reservoir top or as orifices at the overflow level.

Such a configuration of the second chamber provides the advantage that, while having a great length, it holds a comparatively small volume of liquid. Assuming a defective connection for the clutch generator cylinder, the only amount of fluid escaping will reach the first chamber, i.e. the one that overcomes both overflows. Hence, in all positions of inclination in the automotive vehicle and thus the reservoir the level of the highest overflow is of decisive importance.

The remainder of the reservoir volume, feasibly, is subdivided at least into two additional chambers in which are located the two connections for a tandem master cylinder from one connection of which may branch a connection toward the pump of an anti-locking system, if provided, and which are in communication through a lock.

As will be appreciated, reservoirs according to the present invention will be provided in a variety of different forms in dependence upon the type of vehicle concerned.

By way of example the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a cross-sectional top view of a reservoir according to the invention taken in the plane of the minimum permitted filling level; Figure 2 is a cross-sectional underneath view of the 4 reservoir of Figure 1 at the level of the overflows; Figure 3 is one side view of a reservoir according to Figure 1 with overflows, overflow levels and fluid levels shown at a vehicle inclination in the plane of the drawing; and, Figure 4 is another side view of the same reservoir with overflows, overflow levels and fluid levels shown at a vehicle inclination in the plane of the drawing.

From a consideration of Figures 1 and 2 in combination the arrangement of the various reservoir chambers can be appreciated. A connection 3 f or a clutch generator cylinder (not shown) branches from a very small chamber 4 which is located in one corner of the reservoir. Since an overflow 1 from chamber 4 to an adjacent chamber 5 is above the minimum permitted filling level of the reservoir, it is indicated in Figure 2. The chamber 5 which is confined by a partition 12 within the reservoir comprises a narrow channel extending along the reservoir wall 6 and approximately halfway along the reservoir wall 7. The chamber 5 at the end thereof approximately midway along the reservoir wall 7, is in communication with the remainder of the reservoir volume through an overflow 2 which is provided between the minimum and the maximum permitted filling levels in the same way as the overflow 1.

The remainder of the reservoir volume is subdivided into two additional chambers 8 and 9 by a further partition 12. These two chambers are in communication with one an other through a safety lock 13 having an overflow 10 and an orifice 11 below the minimum level. Located in the chambers 9 and 8 are the respective connections 14 and 15 for a tandem master cylinder (not shown) and the respective connections 16 and 17 f or a pump (not shown) of an antilocking system.

The reservoir is sealed by a cap or lid 18 which has a depending f illing level indicator 19 and which is provided with a vent (not shown).

Referring now to Figures 3 and 4, these show two different side views of the reservoir both of which show the positions of the overflows 1 and 2. With the inclination of the reservoir being dependent on the ground level, bleeding of the reservoir in the event of a defective condition of the connection for the clutch generator cylinder is determined by the respective overflow levels at the levels of peak overflow as indicated by Roman numerals. The fluid levels available at an inclination of the reservoir carries respective Latin capital letters as reference characters.

Once the reservoir of Figure 3 is inclined to the left (rotated counter-clockwise) the fluid level A adjusts itself at the overflow level I determined by the overflow 2. The only fluid which can discharge from the connection 3 is that which overcomes the respectively higher overflow, is which, in the present instance, is the overflow 2. The amount of fluid remaining in the reservoir, hence, does not fall under the permitted minimum level.

When the reservoir is inclined to the right (rotated clockwise), the overflow 1 is above the overflow 2 and, hence, determines the overflow level II. However, since the fluid level B will be substantially below that level II, if the reservoir is properly loaded, it is only through a possible slight overspill beyond overflow 1 that a negligible amount of brake f luid could bleed from the narrow chamber 5.

The same considerations apply to the inclination of the reservoir of Figure 4 in opposite directions. The overflow levels III and IV appertaining to the respective opposite directions are determined by the higher positions of the respective overflows 1 and 2 and are substantially above the respective fluid levels C and D. so that a fluid loss can only occur if a heavy motion of the vehicle causes the brake fluid to spill.

6

Claims

CLAIMS:

1. A reservoir f or a hydraulic brake system including a connection f or a generating cylinder of a clutch and serving to release pressure fluid in the event of pad wear, the reservoir having a generally rectilinear or angular compartmented construction with the connection for the clutch generating cylinder being located in one angular area of the reservoir, characterised in that the connection (3) for the clutch generating cylinder is in communication with the remainder of the reservoir interior volume through a bipartite chamber system (4,5), in that a first chamber (4) of the chamber system and in which the connection (3) for the clutch generator cylinder terminates holds, at best, a quarter of the volume of a second chamber (5) in directly adjoining relationship therewith through a first overflow (1) having a lower opening which is at a level between the minimum and maximum permitted filling levels of the reservoir, and in that the second chamber (5) extends at one end f rom the f irst chamber (4) in the f orm of a narrow channel running along one reservoir wall (6) and a portion of another reservoir wall (7) and at the other end thereof has a second overflow (2) with a lower opening therein located between the minimum and maximum permitted f illing levels and forming a connection to the remainder of the reservoir volume.

2. A reservoir as claimed in claim 1, characterised in that the second overflow (2) is arranged approximately at the point where the brake fluid level, at a permitted filling level, is subject to a minimum change when the reservoir is inclined in the plane of the reservoir wall adjacent to which the other end of the second chamber (5) is located.

3. A reservoir for a hydraulic brake system including a connection for a generating cylinder of a clutch and serving to release pressure fluid in the event of pad wear, the reservoir having a circular generally oval or other curved plan configuration, characterised in that a 7 connection (3) for the clutch generating cylinder is in communication with the remainder of the reservoir volume through an at least bipartite chamber system (4,5), in that a first chamber (4) of the chamber system and in which the connection (3) for the clutch generating cylinder terminates, holds, at best, a quarter of the volume of a second chamber (5) in directly adjoining relationship therewith, through a first overflow (1) having a lower opening which is located at a level between the minimum and maximum permitted filling levels of the reservoir, and in that the second chamber (5) extends at one end from the f irst chamber (4) as a narrow channel extending along the reservoir outer wall for a distance corresponding at least to a quarter of the reservoir circumference and having at the end thereof facing away from the first chamber, a second overflow (2) with a lower opening between the minimum and maximum permitted filling level forming a connection to the remainder of the reservoir volume.

4. A reservoir according to any of claims 1 to 3, characterised in that, at least one of the overflows (1,2) comprises a slot extending downwardly from the top of the reservoir in the wall between the first (4) and second (5) chambers or between the second chamber (5) and the remainder of the reservoir volume.

5. A reservoir according to any one of the preceding claims characterised in that at least one of the two overflows (1,2) is formed by a hole provided in the wall between the first (4) and the second chamber (5) and the second chamber (5) and the remainder of the reservoir volume, respectively.

6. A reservoir for a hydraulic brake system substantially as hereinbefore described with reference to the accompanying drawings.

Published 1992 at The Patent Office. Concept House. Cardiff Road, Newport. Gwent NP9 1RH. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Point, Cwmfelinfach, Cross Keys. Newport. NP1 7HZ. Printed by Multiplex techniques lid, St Mary Cray. Kent.