SYSTEM FOR VENTILATING AND VENTING CONTAINERS CONTAINING A FLUID VOLUME

Abstract

A system for ventilating and venting containers containing a fluid volume, such as gearboxes containing an oil filling, with a line system which connects the container concerned to the atmosphere and, upon changes in the volumes located in the container due to temperature changes, permits pressure equalization, is characterized in that the line system contains a separating housing (12) in which a separating medium (46) having oleophobic and hydrophobic properties separates a first space (42), which is connected to the container, from a second space (44), which is connected to the atmosphere, and in that line connections (10, 14) to the separating housing (12) are laid in such a manner that liquid-phase substances deposited on the separating medium (46) can flow out of the first space (42) to the container and out of the second space (44) to the atmosphere.

Description

The invention relates to a system for ventilating and venting containers containing a fluid volume, such as gearboxes containing an oil filling, with a line system which connects the pertinent container to the atmosphere and, upon changes in the volumes located in the container due to temperature changes, enables pressure equalization.

Systems of this type are prior art. Containers which are located in technical systems and which are filled with operating fluids, for example, an oil-filled gearbox, above the oil surface contain a certain air volume which among other things is used for compensation of volume changes of the oil filling which are caused by temperature changes. The line system which leads from the container, for example, a gearbox, to the atmosphere prevents pressure differences from building up that could lead to leaks on the sealing system, for example, on housing passages. In systems which can be operated over a large temperature range, such as, for example, is the case in gearboxes, where there is a large temperature span between the cold start and the operating temperature, in operation considerable volumetric flows of air result within the line system for pressure equalization. In particular, there is the risk that a discharge of oil or oil condensate to the atmosphere with the volumetric flow may occur or an entry of foreign materials from the atmosphere may take place.

With respect to this problem, the object of the invention is to make available a ventilating and venting system which is characterized by an increased amount of operating reliability with respect to preventing the discharge of liquid phase substances and the entry of foreign substance from the atmosphere.

According to the invention, this object is achieved by a ventilating and venting system having the features specified in claim l in its entirety.

Accordingly, an important feature of the invention consists in that the line system contains a separating housing in which a separating medium having oleophobic and hydrophobic properties separates a first space connected to the container from a second space connected to the atmosphere, and that on the separating housing line connections are laid such that liquid phase substances which have been separated on the separating medium can drain out of the first space to the container and out of the second space to the atmosphere. The oleophobic property of the separating medium prevents an overflow of oil to the atmosphere side within the separating housing. At the same time, the hydrophobic property of the separating medium prevents the possibility of an entry of polar fluids, for example water, up to a material-specific pressure difference from the vicinity, while pressure equalization is possible in the form of the air volume without loading with liquid phase substances for a surface which is not completely wetted with liquid. The protection offered by the system according to the invention against ingress of water from the vicinity is especially important and advantageous when the system is used in containers of systems which are operated in a wet environment.

This is especially the case in containers such as gearboxes in automotive engineering where during operation of the vehicles under wet conditions or cleaning of the vehicles in car washes or when washing by hand, the entry of water could be a concern if the protective action offered according to the invention were not present.

In especially advantageous exemplary embodiments, the separating medium is formed by a filter medium which has oleophobic and hydrophobic properties. In this way, the separating medium separates not only water which may enter, but also offers protection against ingress of solid particles. Especially, when used in automotive engineering, this prevents road dust or other dirt particles from being able to travel into the gearbox in operation.

Especially advantageously, the arrangement is made such that there is a mount by means of which the separating housing can be fixed such that in its operating position it lies at a height which is above the container, and that the first space borders the underlying bottom of the separating housing on which the first line connection which leads to the container discharges. This ensures that liquid phase substances such as oil or oil condensate from a pertinent gearbox which have been separated on the separating medium can easily drain completely out of the first space by the action of gravity.

In especially advantageous exemplary embodiments, the separating housing forms a hollow cylinder which surrounds the first and second space and whose axis in the operating position runs horizontally, so that the underlying region of the inner wall of the hollow cylinder forms the bottom which borders the first space and on which the first line connection discharges.

In this case, the arrangement can be advantageously made such that the separating housing has one closed end and one open end which can be closed by a housing cover and that the first line connection is located on the closed end on the radially outer edge of the hollow cylinder.

With respect to the structural configuration of the separating medium, the arrangement can be made such that a cartridge-like filter insert, which can be inserted from the open end of the separating housing, which has the filter medium which forms the separating medium and which in the filter insert forms an inner cylinder which borders the second space and which is open on the end of the separating housing which can be closed by the housing cover. Due to the fluid connection of the second space to the housing cover which has been formed in this way, the second line connection which leads to the atmosphere on the housing cover can be directly provided on this housing cover.

In this respect, the arrangement can advantageously be made such that the housing cover has a central cavity which is connected flush to the open end of the inner cylinder which forms the second space in the closed position which seals the separating housing, with the second line connection on the housing cover forming a drain channel which extends away from the cavity in the radial direction.

In especially advantageous exemplary embodiments, between the housing cover and separating housing, there is a connecting device by means of which the housing cover can be fixed in the closed position such that the second line connection forms a drain channel which is pointed downward for liquid phase substances from the cavity of the housing cover.

In especially advantageous exemplary embodiments, the connecting device is made in the form of a snap safety which has elastic retaining fingers on the housing cover and latch bodies which can be engaged to it by latching on the separating housing, with guide parts which interact with the retaining fingers on the separating housing for the closed position of the housing cover dictating a rotary position with the underlying second line connection. Thus liquid phase substances, for example, water, which has penetrated as far as the filter medium, can flow back again to the atmosphere by the action of gravity.

In especially preferred exemplary embodiments, a bushing of elastomer material can be slipped onto the separating housing such that it forms a snap ring which keeps the retaining fingers latched, and the bushing can be clipped with an annular groove located in its periphery to a carrier part of the mount so that the bushing, in addition to its securing function, forms a flexible support of the separating housing.

The invention is detailed below using one exemplary embodiment which is shown in the drawings.

FIG. 1 shows a broken-away, schematically simplified perspective oblique view of one part of a motor vehicle drive axle with a gearbox which is provided with an exemplary embodiment of the ventilation and venting system according to the invention;

FIG. 2 shows a perspective oblique view of the separately shown exemplary embodiment of the ventilation and venting system according to the invention, shown enlarged compared to FIG. 1;

FIG. 3 shows an exploded perspective of only the separating housing of the exemplary embodiment, shown slightly reduced in size relative to the practical exemplary embodiment, and

FIG. 4 shows a longitudinal section of the separating housing of the exemplary embodiment which is drawn enlarged about 1.5 times compared to a practical exemplary embodiment.

The invention is explained below using an example in which the container which can be ventilated and vented by means of the system according to the invention is the gearbox 2 of the drive axle 4 of a commercial vehicle, which axle is only partially and schematically suggested. In the manner which is conventional in these apparatus, the gearbox 2 is filled with oil, above the oil surface there being a certain air volume. For pressure equalization over the entire operating temperature range of the drive axle 4 at a site on the gearbox 2 which is located at the highest level in the normal installation position of the gearbox 2, there is a ventilation and venting connection 6. The latter is connected to a first line connection 10 of a separating housing 12 via a first hose line 8 which forms a first section of a line system. The separating housing has a second line connection 14 from which a hose line 16 which forms a second section of a line system leads to the atmosphere. A mount 18 which is screwed to the gearbox cover 20 fixes the separating housing 12 in its operating position such that relative to the ventilating and venting connection 6 on the gearbox 2 it is located at a higher level so that the hose line 8 forms a gradient section over which fluid drainage from the separating housing 12 to the gearbox 2 can take place by the action of gravity.

FIG. 2 shows details of the mount 18 with a screw clip 22 for screwing to the housing cover 20 and a carrier part 24 which extends angled upward from the clip 22 and forms the actual support for the separating housing 12. The second hose line 16 which leads from the second line connection 14 of the separating housing 12 to the atmosphere extends from the second line connection 14 a considerable distance downward as far as the hose end 26, which is beveled. This facilitates that the flexible hose is able to elude, for example, the water jet of a washer when the pertinent associated vehicle is being cleaned. At a distance from the hose end 26, the hose line 16 is held by means of an elastic hose support 28 which is clipped in a shoulder 30 which forms the lower end of the mount 18.

FIGS. 3 and 4 show details of the separating housing 12. As is apparent, the separating housing 12, which is made substantially cylindrical, forms in the interior a hollow cylinder 32 with one closed end 34 and one open end 36. On the closed end 34, is the first line connection 10 in a positional arrangement such that the inlet and drain channel 38 into the hollow cylinder 32 discharges on its lowermost region in the normal operating position. This region which is farthest underneath the longitudinal axis 40 of the hollow cylinder 32 forms the first space 42 which borders the inside wall of the hollow cylinder 32. This first space 42 is separated by the separating medium located in the separating housing 12 from the second space 44 which belongs to the atmosphere side.

In this example, the separating medium is formed by a filter medium 46 which has oleophobic and hydrophobic properties and which is part of a cartridge-like filter insert 48 which in the exploded drawing from FIG. 3 is separately visible and can be inserted into the hollow cylinder 32 from the open end 36 in the direction of the arrow 50. The filter medium 46 forms an inner cylinder 74 within a support structure 52 which has been injected molded from plastic with one closed end 54 and one open end 56, which with the filter insert 48 installed is flush with the open end 36 of the hollow cylinder 42. In the region of the open end 56, the support structure 52 is sealed by an O-ring 58 relative to the inner wall of the hollow cylinder 32. Within the hollow cylinder 32, the first space 42 and the second space 44 thus are completely separated from one another by means of the filter medium 46, which is used as the separating medium in terms of an overflow of liquid phase substances in the form of oil or oil condensate from the first line connection 10 or of water from the second line connection 14, while a volumetric flow of air is enabled for pressure equalization between the spaces 42 and 44.

The support structure 52 has webs 60 which run lengthwise and webs 62 which run crosswise, of which not all are visible in FIGS. 3 and 4 and which do not all have the same material cross section. Thus, in the installation position shown in FIG. 4, the web 60 at the top in FIG. 4 has a larger material cross section and adjoins the inside of the hollow cylinder 32. Conversely, according to the drawing on the underlying, lower inner wall region of the hollow cylinder 32, there is not a strip which adjoins it and which runs lengthwise, so that between the filter insert 48 with its altogether three support strips and the inner wall of the hollow cylinder 32, there is an open space which forms the first space 42. The spacer for preserving this open space is a button-like projection 64 which projects slightly radially on the strip 62 which runs crosswise and which is not visible in FIGS. 3 and 4; the projection adjoins the inner wall of the hollow cylinder 32 on the bottom of the first space 42 in the installation position shown in FIG. 4. When the filter insert 48 and the separating housing 12 are joined, as is suggested in FIG. 3 by the motion arrow 50, the filter insert 48 is inserted in the corresponding position. This position is maintained in operation since the O-ring 58 on the open end 56 of the support structure 42 with sealing pretensioning adjoins the inner wall of an edge depression 66 in the end section of the separating housing 12.

The separating housing 12 on the open end 36 can be closed by a housing cover 70 which is shown in FIG. 3. It has a central cavity 72 which, in the closed position shown in FIG. 4, borders the open end 76 of the inner cylinder 74 which is formed by the filter medium 46 and contains the second space 44. From the cavity 72 of the cover 70, which cavity is connected to the second space 46, the second line connection 14 extends in the radial direction downward. There is a connecting device in the form of a snap safety for attaching the cover 70 to the separating housing 12. For this purpose, on the cover 70, there are axially extending retaining fingers 78 and 80 which are peripherally distributed and which have openings 82 which, when the retaining fingers 78 and 80 are slipped onto the cylinder jacket 84, latch to latching bodies 86. To ensure that the cover 70 can be moved into the closed position, i.e., into a snap connection, only when the rotary position shown in FIGS. 3 and 4 prevails, in which the second line connection 14 extends vertically downward, on the separating housing 12 guide bodies 88 are formed between the latch bodies 86, which free distances of varied size between themselves. Matched thereto, the retaining fingers 78 and 80 have a different width so that the cover 70 and the separating housing 12 can be moved together only in one desired rotary position such that the snap connection forms.

A bushing 92 of elastomer material, which is shown separately in FIG. 3 and which is illustrated in FIG. 4 in the action position, in the slipped-on action position forms a snap ring which overlaps the retaining finger 78, 80 and ensures the latch engagement. The bushing 92 has a peripheral annular groove 94 with which it can be clipped into a segment 96 on the carrier part 24 of the mount 18 so that the bushing 92 in an additional function forms an elastic support of the separating housing 12.

For effective protection against ingress of dust or dirt particles from the atmosphere, the filter medium 46 can have a corresponding filter fineness. In this design of the filter medium 46, oleophobic and hydrophobic properties can be implemented with simultaneous permeability to a degree which is necessary for pressure equalization.

Claims

1. A system for ventilating and venting containers containing a fluid volume, such as gearboxes (2) containing an oil filling, with a line system (8, 16) which connects the pertinent container to the atmosphere and, upon changes in the volumes located in the container due to temperature changes, enables pressure equalization, characterized in that the line system (8, 16) contains a separating housing (12) in which a separating medium (46) which has oleophobic and hydrophobic properties separates a first space (42) connected to the container from a second space (44) connected to the atmosphere, and that on the separating housing (12), line connections (10, 14) are laid such that liquid phase substances which have been separated on the separating medium (46) can drain out of the first space (42) to the container and out of the second space (44) to the atmosphere.

2. The system according to claim 1, characterized in that the separating medium is formed by a filter medium (46) which has oleophobic and hydrophobic properties.

3. The system according to claim 1, characterized in that there is a mount (18) by means of which the separating housing (12) can be fixed such that in its operating position it lies at a height which is above the container, and that the first space (42) borders the underlying bottom of the separating housing (12) on which the first line connection (10) which leads to the container discharges.

4. The system according to claim 1, characterized in that the separating housing (12) forms a hollow cylinder (32) which surrounds the first (42) and second (44) space and whose axis (40) in the operating position runs horizontally so that the underlying region of the inner wall of the hollow cylinder (32) forms the bottom which borders the first space (42) and on which the first line connection (10) discharges.

5. The system according to claim 1, characterized in that the separating housing (12) has one closed end (34) and one open end (36) which can be closed by a housing cover (70) and that the first line connection (10) is located on the closed end (34) on the radially outer edge of the hollow cylinder (32).

6. The system according to claim 5, characterized in that a cartridge-like filter insert (48) which can be inserted from the open end (36) of the separating housing (12) has the filter medium (46) which in the filter insert (48) forms an inner cylinder (74) which borders the second space (44) and which is open on the end (36) of the separating housing (12), which end can be closed by the housing cover (70).

7. The system according to claim 1, characterized in that the housing cover (70) has a central cavity (72) which in the closed position which seals the separating housing (12) is connected flush to the open end (76) of the inner cylinder (74) which forms the second space (44), and that the second line connection (14) on the housing cover (70) forms a drain channel which extends out of the cavity (72) away in the radial direction.

8. The system according to claim 1, characterized in that between the housing cover (70) and separating housing (12) there is a connecting device by means of which the housing cover (70) can be fixed in the closed position such that the second line connection (14) in interaction with the cavity (72) of the housing cover (70) forms the drain channel which is pointed downward for substances, especially of a liquid phase.

9. The system according to claim 1, characterized in that the connecting device is made in the form of a snap safety which has elastic retaining fingers (78, 80) on the housing cover (70) and a latch body (86) which can be engaged to it by latching on the separating housing (12), and that guide parts (88) which interact with the retaining fingers (78, 80) on the separating housing (12) for the closed position of the housing cover (70) dictate a rotary position with the underlying second line connection (14).

10. The system according to claim 1, characterized in that a bushing (92) of elastomer material can be slipped onto the separating housing (12) such that it forms a snap ring which keeps the retaining fingers (78, 80) latched, and that the bushing (92) can be clipped with an annular groove (44) located in its periphery to a carrier part (24) of the mount (18) in order to form a flexible support of the separating housing (12).