CN115596827A - Labyrinth ventilation arrangement and gearbox gear shifting unit and gearbox comprising same - Google Patents

Abstract

The invention relates to a labyrinth ventilation arrangement and a gearbox gear shifting unit and a gearbox comprising the same. A venting arrangement for a gearbox shift unit or gearbox comprising: an air scoop formed within the housing, the air scoop including opposing first and second ends, the first end of the air scoop configured for communication with an interior of the transmission case; the cavity is formed in the shell and communicated with the second end of the air inlet channel; an exhaust stack formed within the housing, the exhaust stack including opposing first and second ends, the first end of the exhaust stack in communication with the cavity, the second end of the exhaust stack configured for communication with an external environment; and a fluid-surrounding body mounted within the cavity such that a tortuous flow path is defined around at least a portion of the fluid-surrounding body by at least the fluid-surrounding body.

Description

Labyrinth ventilation arrangement and gearbox gear shifting unit and gearbox comprising same

Technical Field

The present invention relates to a labyrinth ventilation arrangement for a gearbox gear unit or gearbox, and a gearbox gear unit and gearbox comprising the same.

Background

When the gearbox works or the outside temperature changes, the temperature in the gearbox changes, so that the gas in the gearbox expands or contracts. It is desirable to exchange air with the space outside the transmission to maintain a balance of air pressures inside and outside.

When the gearbox works, oil at the bottom of the gearbox is thrown out by the rotating gear and volatilizes when the internal temperature rises, but the oil is not expected to escape from the internal space of the gearbox.

Disclosure of Invention

Accordingly, it is desirable in the art to communicate the air pressure within the transmission to the outside environment, allowing air flow inside and outside the transmission, even when the transmission is subject to temperature changes. It is desirable in the art to avoid oil that may be entrained mist and/or droplets from escaping the transmission. It is desirable in the art to maintain the structure simple.

According to some aspects of the present invention there is provided a venting arrangement for a gearbox shift unit or gearbox, comprising: an air scoop formed within the housing, the air scoop including opposing first and second ends, the first end of the air scoop configured for communication with the transmission case interior; the cavity is formed in the shell and communicated with the second end of the air inlet channel; an exhaust passage formed within the housing, the exhaust passage including opposing first and second ends, the first end of the exhaust passage being in communication with the cavity, the second end of the exhaust passage being configured for communication with an external environment; and a fluid-surrounding body mounted within the cavity such that a tortuous flow path is defined around at least a portion of the fluid-surrounding body by at least the fluid-surrounding body. Due to the presence of the bypass, when considering flow from the inlet port to the outlet port via the cavity, at least part of the flow may be caused to change direction, bypass at least part of the bypass, travel through a tortuous flow path (labyrinth chamber) defined by the bypass or by the bypass and the inner walls of the cavity (and/or other components), such a labyrinth flow path may be elongated and tortuous (e.g. as compared to directly from the inlet port to the outlet port via the cavity), increasing the direction of travel, the travel path of the flow (particularly oil and gas flow) and the contact or heat exchange with the traveling components (e.g. the bypass, the inner walls of the cavity and/or other components). The fluid-wound body is also referred to as a labyrinth body, and is manufactured separately and easily attached and fixed.

According to some aspects of the invention, the fluid-surrounding body includes a main body and first and second flanges at opposite ends of the main body, the first and second flanges being formed with a cutaway portion, the first and second flanges except for the cutaway portion being sized to mate with respective portions of an inner wall of the cavity. Since each flange at the notch partially forms an opening allowing the flow to pass through, at least part of the flow, which is stopped for example by the rest of the flange, will change direction to bypass these parts and lead to said opening. Furthermore, a surrounding space around the body is formed between the first flange and the second flange, which provides a flow path for a flow, in particular a flow of an oil or gas stream, such that at least part of the flow may flow around at least part of the body. In this way an effective and structurally simple fluid winding is obtained.

According to some aspects of the invention, the notch portions of the first and second flanges are located at first and second angular positions, respectively, relative to the main body that are different from each other, preferably at opposite angular positions of substantially 180 degrees. Due to the circumferentially staggered openings allowing flow therethrough, at least part of the flow is further encouraged to flow around at least a portion of the body.

According to some aspects of the invention, the inner wall of the cavity includes a shoulder portion against which a first flange of the surrounding fluid is positioned and an enlarged cross-sectional portion opposite the shoulder portion at which a second flange is positioned. In this way, the position and/or orientation of the fluid-surrounding within the cavity may be advantageously defined, for example, such that the fluid-surrounding is less likely to be adversely loaded.

According to some aspects of the present invention, the air inlet passage is provided obliquely in the housing. Due to the limited size of the housing, in particular its thickness, the inclination of the inlet channel lengthens the travel path of the flow before it enters the cavity.

According to some aspects of the invention, the exhaust passage is disposed substantially horizontally within the housing. In this way, foreign bodies, such as particles, can advantageously be prevented from falling back into the chamber via the exhaust duct. Preferably, the second end of the exhaust passage is further provided with an exhaust plug.

According to some aspects of the invention, the inlet and outlet ports are located at opposite end portions of the cavity. In this way almost the entire length of the cavity is effectively utilized. Preferably, the length of the cavity extends mainly in the direction of the basic housing thickness.

According to some aspects of the invention, the breather arrangement further comprises an oil baffle disposed adjacent the first end of the intake duct on a side of the housing intended to face an interior of the transmission. Preferably, the oil deflector comprises an oil deflector that is substantially parallel or angled with respect to a surface of the housing intended to face the interior of the gearbox. Due to the arrangement of the oil baffle plate, oil drops thrown out by the rotating gear are at least partially blocked and cannot enter the air inlet channel. Accordingly, at least a portion of the flow also needs to flow around the oil deflector to enter the inlet passage.

According to some aspects of the present invention, a virtual extension line of the air inlet passage in a length direction intersects a surface of the at least one oil deflector. Thus, oil drops, even solid impurities and the like except for the air flow can be favorably prevented from entering the air inlet channel.

According to some aspects of the invention, the venting arrangement further comprises a filter element located within the cavity, the filter element being located at least partially between the second end of the air inlet channel and the fluid-surrounding body. In this way, a barrier is formed in the chamber between the inlet and outlet ducts, which may be advantageous to prevent the passage of solid impurities and even oil droplets.

According to some aspects of the present disclosure, the venting arrangement further includes an inner post extending into the cavity across the first end of the exhaust passageway. In this way, the inner column forms an additional flow-around configuration, which also forms a surrounding space (e.g. in combination with the inner wall of the cavity), providing an additional flow path for the flow, thereby advantageously acting in conjunction with the aforementioned flow-around. Preferably, the inner post has an opening through which the coiled fluid is arranged to be secured by means of a fastener, such as a bolt or screw. In this way, the additional bypass construction also has multiple uses, making full use of the compact space within the housing, particularly the cavity. Preferably, the end surface of the inner post is substantially flush with the base surface of the shoulder portion. In this way, a fast and stable positioning and fixation of the surrounding fluid is facilitated.

According to some aspects of the invention, the housing comprises an upper housing and a lower housing, the cavity being formed within both the upper housing and the lower housing, preferably a majority of the length of the cavity being formed in the upper housing, the air inlet being formed in the lower housing, the air outlet being formed in the upper housing, the filter element being positioned in the lower housing, the surrounding fluid being positioned in the upper housing. Thus, space utilization, installation convenience, and assembly compactness are enhanced. Furthermore, a certain degree of freedom is obtained in the design of the cavities, so that the cavities may differ in the dimension perpendicular to the length in the upper and lower housing, for example to accommodate the components positioned therein, respectively. Preferably, the housing comprises a housing of a gearbox or gearbox shifting unit, or the upper and lower housings comprise upper and lower housings of a gearbox shifting unit, wherein the gearbox shifting unit is configured for positioning on top of a gearbox housing.

According to some aspects of the present invention there is provided a gearbox shift unit comprising the venting arrangement of the above aspects.

According to some aspects of the present invention there is provided a gearbox comprising a venting arrangement of the above aspects and/or a gearbox shift unit having a venting arrangement of the above aspects, the gearbox shift unit being configured for positioning on top of a gearbox housing.

Drawings

FIG. 1 illustrates a schematic diagram of at least a portion of an exemplary transmission case.

FIG. 2 shows a schematic view of at least a portion of an exemplary transmission shift unit.

Fig. 3 illustrates a partially cut-away perspective view of a venting arrangement according to various embodiments.

Fig. 4 illustrates a perspective view of components of a venting arrangement according to various embodiments.

Fig. 5 illustrates a partial cut-away plan view of a venting arrangement according to various embodiments.

Fig. 6 illustrates a partial cut-away plan view of a venting arrangement according to various embodiments.

Detailed Description

The present invention is described with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth and described herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It will also be appreciated that the embodiments disclosed herein may be combined in any manner and/or combination to provide many additional embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description above is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

For purposes of illustration, the same reference numbers will be used in the drawings to refer to the same or like devices, units and/or components, and the parts will not necessarily be to scale.

Referring now to FIG. 1, FIG. 1 illustrates at least a portion of an exemplary transmission 1. Generally, the gearbox 1 may comprise a casing 11. According to some embodiments, the gearbox 1 may further comprise a top cover assembly 12, wherein the top cover assembly 12 may for example comprise a gearbox gear shifting unit. A cover assembly 12 (or transmission shift unit) may be provided on top of the housing 11. The housing 11, the head assembly 12 (or gearbox gear shift unit) forms a housing 10 enclosing the gearbox 1. Of course, it will be apparent to those skilled in the art that other various configurations of the transmission 1 (e.g., a one-piece case, etc.) may be used without departing from the spirit and scope of the present application.

Referring now to fig. 2, fig. 2 illustrates at least a portion of an exemplary transmission shift unit 2. In general, the gearbox shifting unit 2 may comprise a housing 20, a fork 21 extending to the outside and/or electromechanical components arranged inside. An external connector 22 is also depicted. The overall height of the housing 20 of the gearbox shifting unit 2 may be small, for example in the order of about 60 mm.

According to some embodiments, the housing 20 includes an upper housing 201 and a lower housing 202, which may be connected to each other, for example, by fasteners distributed around the perimeter or by other means. The upper and lower housings 201, 202 of the housing 20 may be engaged by gaskets, for example, in order to seal off the interior of the transmission shift unit 2 from the exterior. Of course, it will be apparent to those skilled in the art that other various configurations of the transmission shift unit 2 (e.g., a one-piece housing, etc.) may be used without departing from the spirit and scope of the present application.

Generally, the interior of the transmission (excluding the interior of the transmission shift unit) requires air exchange with the external space to maintain a balance of internal and external air pressures to prevent seal arrangements in the transmission and the shift mechanism from being damaged. However, the oil at the bottom of the transmission is carried by the rotating gear in operation and thrown up into the space, and the oil may volatilize when the internal temperature rises. It is undesirable for oil within the transmission to be lost and escape causing contamination, but it is desirable for air to be free to enter and exit. In particular, in view of the available space (e.g. thin housings, etc.), there is a need to provide an effective venting arrangement that is simple in construction.

Referring now to fig. 3, fig. 3 illustrates at least a portion of a venting arrangement 3 according to various embodiments. The venting arrangement 3 is applicable to a gearbox (e.g. the exemplary gearbox 1), in particular a gearbox gear unit (e.g. the exemplary gearbox gear unit 2), and is formed with respect to the housing 30.

According to some embodiments, the housing 30 comprises an upper housing 301 and a lower housing 302, which may be connected to each other, for example, by fasteners distributed around the circumference or by other means. Although a particular housing composition and housing geometry is shown, it will be apparent to those skilled in the art that other housing compositions and housing geometries (e.g., one-piece housings, housings of different thicknesses, etc.) may be used without departing from the spirit and scope of the present application.

According to some embodiments, the venting arrangement 3 comprises an air inlet channel 31 formed in the housing 30. The inlet channel 31 includes opposing first and second ends 311 and 312. The first end 311 of the inlet channel 31 is configured for communication with the gearbox interior. The venting arrangement 3 comprises a cavity 32 formed within the housing 30. The cavity 32 communicates with the second end 312 of the inlet passage 31. The venting arrangement 3 comprises an exhaust duct 33 formed in the housing 30. The exhaust passage 33 includes opposing first and second ends 331 and 332. A first end 331 of the exhaust passage 31 is in communication with the cavity 32, while a second end 332 of the exhaust passage 31 is configured for communication with the external environment. The venting arrangement 3 comprises a surrounding fluid 34. The coiled fluid 34 is mounted within the cavity 32 such that a tortuous flow path around at least a portion of the coiled fluid 34 is defined by at least the coiled fluid 34 (which may also be defined by the inner wall 320 and/or other components of the cavity 32). Here, the first end 311 of the inlet duct 31 for communication with the interior of the gearbox advantageously opens on the surface S of the casing 30 intended to face towards the interior of the gearbox, while the second end 332 of the outlet duct 33 for communication with the external environment can open on the surface of the casing 30 intended to face towards the external environment, or alternatively be connected to an intermediate configuration for communication with the external environment.

Referring now to fig. 4, fig. 4 illustrates a configuration of the fluid enclosure 34 in accordance with various embodiments.

According to some embodiments, the coiled fluid 34 includes a main body 340 and first and second flanges 341, 342 located at opposite ends of the main body 340. The first and second flanges 341, 342 are formed with notches 3410, 3420, except for the notches 3410, 3420, the first and second flanges 341, 342 being sized to mate with corresponding portions of the inner wall 320 of the cavity 32, respectively. Here, the matching may include a clearance fit. In particular, the notched portions 3410, 3420 do not overlap with the main body 340 and are therefore less likely to be too large.

According to some embodiments, the body 340 about the fluid 34 may be substantially cylindrical. Additionally or alternatively, the first and second flanges 341, 342 may extend substantially parallel to one another, substantially perpendicular with respect to the main body 340, and/or have planar end surfaces that are substantially parallel to one another. Thus, the wound fluid 34 may be formed into a spool-like shape.

According to some embodiments, the notched portions 3410, 3420 may be formed in a substantially flat shape, and the outer circumferences of the first and second flanges 341, 342 may form a substantially circumference, except for the notched portions 3410, 3420. Accordingly, at least the respective portion of the inner wall 320 of the cavity 32 may be cylindrical. Where the outer peripheries of the flanges 341, 342 form a substantially circumferential shape and the corresponding portion of the inner wall 320 is cylindrical, the circumferential orientation within the cavity 32 around the fluid 34 may be flexible, which facilitates assembly in low accessible spaces, for example.

The wrap 34 of fig. 4 may be conveniently formed using machining, such as turning, milling. Although a particular shape is shown and described, it will be apparent to those skilled in the art that other shapes (e.g., prismatic bodies, notched cutout portions, polygonal/elliptical flange outer/inner wall corresponding portions, etc.) may be used without departing from the spirit and scope of the present application.

According to some embodiments, the first and second flanges 341, 342 may be provided with a chamfer or radius at the rim and/or at the junction with the body 340.

According to some embodiments, the notch portions 3410, 3420 of the first and second flanges 341, 342 are located at first and second angular positions, respectively, relative to the main body 340 that are different from each other. Further, the first and second angular positions of notch portions 3410, 3420 may be substantially opposite one another, or substantially 180 degrees.

Referring now to fig. 5-6, fig. 5-6 illustrate at least a portion of a venting arrangement 3 according to various embodiments. Fig. 5-6 show further details of the venting arrangement 3.

According to some embodiments, the inner wall 320 of the cavity 32 includes a shoulder portion 321 and an enlarged-cross-section portion 322 opposite the shoulder portion 321, a first flange 341 around the fluid 34 is positioned against the shoulder portion 321, and a second flange 342 around the fluid 35 is positioned at the enlarged-cross-section portion 322. The shoulder portion 321 may be closer to the first end 331 of the exhaust passage 33 than the enlarged-section-area portion 322, or the shoulder portion 321 may be farther from the second end 312 of the intake passage 31 than the enlarged-section-area portion 322. In the case where the outer peripheries of the flanges 341, 342 form a substantially circular circumference and the corresponding portion of the inner wall 320 is cylindrical, the outer diameter of the first flange 341 may be smaller than the outer diameter of the second flange 342.

According to some embodiments, the air inlet duct 31 is obliquely arranged within the housing 30. Additionally or alternatively, the exhaust duct 33 is disposed substantially horizontally within the housing 30. Further, the second end 332 of the exhaust passage 33 may also be provided with an exhaust plug (not shown).

According to some embodiments, the inlet 31 and outlet 33 channels are located at opposite end portions (e.g., opposite in a direction along the length of the cavity) of the cavity 32 (at least around the fluid 34 located therein, forming a labyrinth cavity). Further, the second end 312 of the inlet duct 31 and/or the first end 331 of the outlet duct 33 may open onto a surrounding portion of the inner wall 320 of the cavity 32 at a respective end portion of the cavity 32. Then, if the cavity 32 also includes end walls 323, 324, the second end 312 of the inlet duct 31 and/or the first end 331 of the outlet duct 33 may open proximate the respective end walls 323, 324 of the cavity 32, but may not open into the respective end walls 323, 324.

According to some embodiments, the second end 312 of the inlet duct 31 and the first end 331 of the outlet duct 33 are located, with respect to the cavity 32, at a first angular position and a second angular position, respectively, which are different from each other. Further, the first and second angular positions of the second end 312 of the inlet duct 31 and the first end 331 of the outlet duct 33 may be approximately 90 degrees.

According to some embodiments, the venting arrangement 3 further comprises oil baffle plates 35a, 35b. The oil deflector 35a, 35b is arranged near the first end 311 of the inlet channel 31 on the side of the housing 30 intended to face the interior of the gearbox. Further, the oil deflector may include an oil deflector 35a that is substantially parallel with respect to the surface S of the housing 30 for facing the transmission case interior. Additionally or alternatively, the oil deflector may comprise an oil deflector 35b angled relative to the surface S of the housing 30 intended to face the interior of the gearbox. The oil deflector may also have an additional function, in particular, at least one oil deflector 35a, 35b is arranged in connection with the oil temperature probe such that at least one surface of the at least one oil deflector 35a, 35b is configured for guiding oil droplets to the oil temperature probe.

According to some embodiments, a virtual extension line of the air intake duct 31 in the length direction intersects a surface of the at least one oil deflector 35a, 35b.

According to some embodiments, the venting arrangement 3 further comprises a filter element 36 located within the cavity 32. The filter element 36 is positioned at least partially between the second end 312 of the inlet channel 31 and the bypass stream 34. The filter element 36 may be secured by a detent 325 disposed on the inner wall 320 of the cavity 32.

According to some embodiments, the ventilation arrangement 3 further comprises an inner post 37 extending across the first end 331 of the exhaust duct 33 (e.g. extending beyond the extent of the first end 331 in a direction along the length of the cavity) into the cavity 32. Further, the inner post 37 may have an opening 370, and the coiled body 34 may be configured to be secured by a fastener 38 (e.g., a bolt or screw) through the opening 370 of the inner post 37. For example, the fastener 38 may be inserted through a through hole around the fluid 34 and into the opening 370 of the inner post 37. Additionally or alternatively, the end surface of the inner post 37 is substantially flush with the base surface of the shoulder portion 321. Therefore, the outer end face of the first flange 341 around the fluid 34 may abut against the end face of the inner column 37 at a substantially central portion (except for the through hole) in addition to the base face abutting against the shoulder portion 321 at the peripheral portion.

According to some embodiments, the housing 30 may comprise the housing 10 of the gearbox 1 or the housing 20 of the gearbox gear unit 2.

In an embodiment in which the housing 30 includes an upper housing 301 and a lower housing 302, the two may be joined by a gasket 300, and may have the following configuration:

the cavity 32 is formed in both the upper case 301 and the lower case 302 across both; for example, the upper and lower cases 301 and 302 may include recesses facing each other at corresponding positions. In the case where the majority of the length of the cavity 32 is formed in the upper case 301, the recess of the upper case 301 may have a greater depth than the recess of the lower case 302.

The intake duct 31 is formed in the lower housing 302; for example, the air inlet channel 31 may extend, in particular obliquely, in the lower housing 302, for example from the surface S for facing the interior of the gearbox towards the cavity 32, for example a recess of the lower housing 302.

The exhaust passage 33 is formed in the upper case 301; for example, the air duct 33 may extend, in particular substantially horizontally, in the upper housing 301 from the cavity 32, for example from a recess of the upper housing 301.

The cartridge 36 is positioned in the lower housing 302; for example, the cartridge 36 may be secured at the mouth end of the recess of the lower housing 302, but may not extend beyond the recess of the lower housing 302. If present, detents 325 of cartridge 36 can be formed at the mouth end of the recess of lower housing 302.

Positioned in the upper housing 301 about the fluid 34; for example, the shoulder portion 321 may be formed on an inner wall of a recess of the upper housing 301, and/or the inner post 37 may extend into the cavity 32, e.g., into the recess of the upper housing 301. The fluid wrap 34, e.g., a first flange 341 thereof, may be positioned by seating against the shoulder portion 321 (base surface) and/or the inner post 37 (end surface), but the fluid wrap 34, e.g., a second flange 342 thereof, may not extend beyond the recess of the upper shell 301. Accordingly, the enlarged-section portion 322 may be closer to the mouth end of the recess of the upper casing 301 than the shoulder portion 321.

Note that one or more of the features described with respect to the upper and lower cases 301 and 302 may be advantageously applied to the upper and lower cases 201 and 202. That is, the upper and lower housings 301, 302 of the housing 30 are the upper and lower housings 201, 202 of the gear shift unit of the transmission, and the functions thereof are integrated into the gear shift unit, so that the breathing function can be realized after the gear shift unit is mounted on the transmission.

According to some embodiments, there is also provided a gearbox gear shifting unit comprising a venting arrangement 3 according to various embodiments. Additionally or alternatively, a gearbox is also provided, comprising a venting arrangement 3 according to various embodiments and/or a gearbox gear unit with a venting arrangement 3 according to various embodiments. According to some embodiments, the gearbox, gearbox shifting unit may comprise one or more of the features described in relation to the exemplary gearbox 1, gearbox shifting unit 2.

According to the invention, a labyrinth flow path is formed in the cavity by the surrounding fluid and the additional inner column, gas in the gearbox passes through the labyrinth, oil mist condensation flows back, air exchange between the inside and the outside of the gearbox is allowed, and oil overflow is prevented; the additional oil baffle prevents the direct throwing of engine oil into the venting arrangement; the inclined air inlet channel fully utilizes the limited shell height and prolongs the flow path; the additional filter element separates and blocks impurities.

For example, a favorable draining flow in the preferred counter-gravitational direction (and therefore the orientation of placement in the illustration may correspond approximately to the orientation of the working state) may occur: the flow enters the first end of the inlet duct where it may be desired to at least partially bypass the oil deflector, flows out of the second end of the inlet duct along the advantageously upwardly inclined inlet duct, enters the cavity, in particular to the lower end portion thereof, reaches the winding body where it may be desired to pass upwardly through the filter element, where the flow will be caused at least partially to pass through a tortuous flow path around at least a portion of said winding body, where in the case of the aforementioned spool-type advantageously winding body at least part of the flow will bypass the blocked lower flange portion and enter the surrounding space of the body surrounding said winding body from the lower indentation, flow around at least a portion of the body, bypass the blocked upper flange portion and exit the surrounding space from the upper indentation and thus exit the winding body, flow exits the cavity, in particular the upper end portion thereof, after it may be desired to at least partially flow around at least a portion of the inner column, enters the first end of the outlet duct, flows out of the second end of the outlet duct along the advantageously horizontal outlet duct. Accordingly, the inlet flow may be reversed to be substantially opposite to the outlet flow described above.

The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Claims (14)

1. A venting arrangement for a gearbox shift unit or gearbox comprising:

an air scoop formed within the housing, the air scoop including opposing first and second ends, the first end of the air scoop configured for communication with an interior of the transmission case;

the cavity is formed in the shell and communicated with the second end of the air inlet channel;

an exhaust passage formed within the housing, the exhaust passage including opposing first and second ends, the first end of the exhaust passage being in communication with the cavity, the second end of the exhaust passage being configured for communication with an external environment; and

a fluid-surrounding body mounted within the cavity such that a tortuous flow path around at least a portion of the fluid-surrounding body is defined by at least the fluid-surrounding body.

2. A venting arrangement as claimed in claim 1, wherein the fluid-surrounding body comprises a main body and first and second flanges at opposite ends of the main body, the first and second flanges being formed with a cutaway portion, the first and second flanges being dimensioned for mating with respective portions of an inner wall of the cavity, except for the cutaway portion.

3. The venting arrangement of claim 2, wherein the notch portions of the first and second flanges are located at opposing angular positions of substantially 180 degrees relative to the main body.

4. The venting arrangement of claim 2 or 3, wherein the inner wall of the cavity comprises a shoulder portion against which a first flange surrounding the fluid is positioned and an enlarged-section portion opposite the shoulder portion at which a second flange is positioned.

5. The venting arrangement of any one of claims 1 to 3, wherein the inlet duct is arranged obliquely within the housing, and/or the outlet duct is arranged substantially horizontally within the housing, and/or the inlet and outlet ducts are located at opposite end portions of the cavity.

6. The venting arrangement of any one of claims 1 to 3, further comprising an oil deflector provided near the first end of the air inlet channel on a side of the housing intended to face the interior of the gearbox.

7. The venting arrangement of claim 6, wherein a virtual extension of the air scoop in a length direction intersects a surface of at least one oil deflector.

8. The venting arrangement of any one of claims 1-3, further comprising a filter element located within the cavity, the filter element being positioned at least partially between the second end of the inlet channel and the flow-wrap.

9. The venting arrangement of any one of claims 1-3, further comprising an inner post extending into the cavity across the first end of the exhaust passage.

10. The venting arrangement of claim 9, wherein the inner post has an opening through which the fluid-surrounding arrangement is secured by a fastener.

11. The venting arrangement of claim 4, further comprising an inner post extending into the cavity across the first end of the exhaust passage, an end surface of the inner post being substantially flush with a base surface of the shoulder portion.

12. The venting arrangement of any one of claims 1 to 3, wherein the housing comprises an upper housing and a lower housing, the cavity being formed within both the upper housing and the lower housing, the air inlet passage being formed in the lower housing, the air outlet passage being formed in the upper housing, the fluid-surrounding being positioned in the upper housing.

13. A gearbox gear shift unit comprising a venting arrangement according to any one of claims 1 to 12.

14. A gearbox comprising a venting arrangement according to any one of claims 1 to 12 and/or a gearbox gear unit according to claim 13.

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