BRAKE FLUID RESERVOIR WITH PRESSURE BALANCING

A brake fluid reservoir includes in its upper portion a bottleneck with a thread and a top for receiving a cap with an edge and a top. The top of the bottleneck has channel opens into the atmosphere, one end of the channel leading into the atmosphere, one end of the channel leading into the interior of the bottleneck and the other end communicating with the outside atmosphere via a cavity.

FIELD OF THE INVENTION

The present invention concerns a brake fluid reservoir with an air vent for pressure balancing, the top of the reservoir body being equipped with a threaded neck accommodating a threaded cap on the neck and having a baffled passageway for venting the reservoir.

BACKGROUND INFORMATION

The realization of brake fluid reservoirs with pressure balancing is known. There exist different embodiments of reservoirs wherein the cap has an element forming a baffle enabling the pressure to be balanced while preventing brake fluid from escaping due to the effect of the vehicle's sudden acceleration or deceleration, for example, if the brakes are applied suddenly. These solutions are not always satisfactory, however, because the risk of the fluid escaping remains due to the orientation of the baffle, which can be incorrectly oriented with respect to the vehicle axis.

Document EP 2,189,344 discusses a brake fluid reservoir equipped with a pressure balancing arrangement, thereby avoiding the risk of brake fluid escaping under exceptional conditions through the particular orientation of the outlet of the cap by indexing the seal forming the baffle equipping the interior of the cap. This seal is positioned precisely so that the cap, once screwed into place, is suitably oriented and so that the outlet of the baffle is not turned toward the front, an orientation that would be the most favorable for the escape of brake fluid from the baffle through the effect of sudden braking.

But this solution, although interesting, has the disadvantage of being complex to realize given that the cap consists of the cap body in the form of a lid with an indexed thread and accommodates the seal forming a baffle, which is itself indexed, by a connecting arrangement that respects the indexing. Finally, a gasket is placed between the cap equipped with its baffle and the top of the neck. The neck must also have an indexed thread so that, when the cap is screwed in place, the baffle will have the correct orientation.

This solution has the disadvantage of complex manufacture and additional assembly operations resulting in relatively high costs overall.

SUMMARY OF THE INVENTION

An object of the present invention is the realization of a brake fluid reservoir with pressure balancing that is especially simple to produce and use, so as to reduce the cost of the reservoir and ensure the efficiency of the pressure balancing while avoiding the risk of brake fluid escaping.

To that end, an object of the invention is a brake fluid reservoir of the type described above, characterized in that,

A) the neck has a top with a pressure balancing channel,open on top,having a first extremity forming an entrance communicating with the interior of the reservoir and a second extremity forming an outlet communicating with the surrounding atmosphere,occupying at least one portion of the periphery of the top of the neck,this channel, situated on the interior of the neck, being surrounded on the exterior by a sealing surface,

B) the cap consists of:a peripheral edge equipped with internal threading corresponding to the external threading on the neck, anda flat bottom that engages with the top of the neck when the cap is screwed on,an annular contact surface between the sealing lip and the edge of the cap, this surface being equipped with an opening straddling the outlet region of the channel to constitute the outlet of the channel when the cap is screwed onto the neck.

The reservoir according to the invention has the advantage of having a one-piece cap incorporating the air vent portion. Likewise, the top of the neck incorporates the channel forming the baffle in such a way that realization of the assembly is especially simple. Use is also simple and the cap can be very easily placed in the appropriate position not only to enable communication between the interior of the brake fluid reservoir and the exterior and balance the pressure to avoid any vacuum in the reservoir even in the event of significant and rapid extraction of brake fluid during braking, but also ensuring that there is no risk that the liquid shaken in the reservoir will escape through the balancing path formed by the channel specifically during a sudden braking action.

According to an advantageous characteristic, the entrance of the channel is a lateral entrance crossing the partition bordering the channel on the interior.

This lateral entrance is realized very simply with a mold without requiring any moving parts because this lateral entrance is open on top.

According to another advantageous characteristic, the channel occupies almost the entire periphery of the upper portion of the neck and is circular in shape, its inlet being separated from its outlet by a partition.

This circular embodiment of the channel is particularly simple because the channel is circular in shape and the inlet and outlet in the channel are simply separated by a partition, the inlet emerging in the reservoir laterally through removal of a portion of the wall, whereas the outlet communicates from above.

According to another advantageous characteristic, the pressure balancing channel makes more than one peripheral turn in the upper portion of the neck.

According to another advantageous characteristic, the flat bottom has a circular sealing lip occupying a position corresponding to the opening of the neck when the cap is screwed onto the neck so that the circular sealing lip inside the neck engages with the partition bordering the channel on the interior.

This sealing lip completes the seal of the channel over the entire periphery without interfering with the opening of the entrance to the channel, which can pass beneath the lip. This lip ensures the effectiveness of the pressure balancing path consisting of the channel once the cap is screwed onto the neck.

According to another advantageous characteristic, the outlet is an opening in the shape of a cavity communicating with the threaded region of the cap and that of the neck.

According to another advantageous characteristic, the upper portion of the neck has, upon its outer surface, an orientation marker for determining the screw position of the cap.

The present invention will be described in greater detail by an example of a brake fluid reservoir with pressure balancing, shown schematically in the attached drawings.

DETAILED DESCRIPTION

According toFIG. 1, brake fluid reservoir1, shown very partially, has top11, equipped with a threaded neck12, closed by screw cap2, so the reservoir can be filled while ensuring that the pressure is balanced inside the reservoir. The balancing must occur rapidly during operation of the brake system in the event of the rapid removal of brake fluid for this pressure to be at atmospheric pressure, preventing the creation of a pressure drop that would block the extraction of brake fluid by the master cylinder supplied by reservoir1.

Cap2has edge21with interior threads,211corresponding to threads121of neck12and bottom22. On the outside, cap2is equipped with portions in relief,212, to facilitate gripping it when tightening or loosening.

According toFIG. 2, neck12has, beyond exterior threads121, upper portion122having, on the inside (IG) of the neck, balancing channel123that is open on top. This balancing channel,123, recessed into upper portion122, there occupies a significant portion of the periphery. In this embodiment, channel123occupies almost the entire periphery. It is bordered, on the inside (IG) by partition124and on the outside of the neck by annular sealing surface125.

As shown inFIG. 2, channel123has first extremity123awith an inlet consisting of notch1231in interior partition124and second extremity123b,corresponding to the outlet or outlet region123b.Channel123, which almost entirely occupies the periphery of top122of neck12, separates its inlet123aand its outlet region123bwith partition1232in such a way that inlet123aof channel123and its outlet123bare unable to communicate directly. Communication between inlet123aand outlet123boccurs solely through channel123when cap2is screwed in place.

As shown inFIGS. 1,3,4, cap2, in the shape of a top, has peripheral edge21, whose interior surface is provided with threads212for screwing to threads121of neck12and flat bottom22(FIG. 4), from which circular sealing lip221extends. The geometry of this circular lip221is such that whenever cap2is screwed to neck12, it enters the neck and is applied to interior partition124bordering channel123. Beyond lip221, bottom22is flat and forms an annular contact surface222intended to surmount upper portion122of neck12, including channel123and partition124, in such a way as to create a pressure balancing conduit between inlet123aof channel123and its outlet123b.

Annular contact surface222is equipped with cavity-shaped opening2221, which crosses this surface222, for example, in a radial direction so that, when cap2is screwed onto neck12, opening2221straddles channel123, thereby constituting the outlet of the channel.

Cap2is screwed in such a way that its opening2221encounters outlet region123bof channel123. On the exterior, cap2has marker223, indicating open position2221, so it can be positioned by screwing it to the appropriate location.

Cap2can also be indexed by the configuration of its threads211and those121of neck12so that, when it is completely screwed in place, opening2221of cap2is found in outlet region123bof the channel.

Cap2being screwed on neck12forms, with channel123, a communication path with a very narrow cross-section, therefore with a significant pressure drop between the channel inlet and its outlet, which enables pressure to be balanced inside reservoir1to bring it to atmospheric pressure while preventing brake fluid from escaping from the reservoir through cap2.

Depending on the installation position of reservoir1in the engine compartment, cap2will be oriented in the most suitable manner to prevent the sudden movement of brake fluid in the reservoir, for example, during sudden braking, from being pushed through the channel to the outlet. The outlet is oriented toward the back, which corresponds to the position toward which there is the least risk of brake fluid being pushed or being pushed violently and being forced through the channel and leaking through the cap.

According to a variant not shown, channel123, which, in the above example, occupies almost the entire periphery of upper portion122of the neck, can also be shorter in length and occupy only a fraction of that periphery or have a length that extends over more than one turn in the top of the neck. In this case, cavity shaped opening2221straddles only the outlet region of this channel without straddling another portion of the channel in such a way that the communication path between the reservoir inlet and outlet for balancing extends over the entire length of the channel.

The brake fluid reservoir and its cap are made simply of molded plastic material. The shape of the neck as well as the cap allow for very simple manufacture without requiring a complex mold and moving elements.

REFERENCE KEY

1brake fluid reservoir11top of reservoir12threaded neck of reservoir121neck threads122top of neck123channel123afirst extremity of channel123bsecond extremity of channel1231notch of first extremity123aof the channel1232partition of second extremity123bof the channel124interior partition delimiting channel123125annular sealing surface2cap21edge211threads212raised part22bottom of cap221sealing lip222annular contact surface2221cavity shaped opening223markerIG interior of neck12