GEARBOX WITH FAN ARRANGEMENT

Description

[0001] The invention relates to a transmission with a fan arrangement.

[0002] It is generally known that a fan assembly can be used to cool a device.

[0003] From the DE 10 2008 010 912 A1 The closest state of the art is a fan wheel and a fan cover with a fan grille formed integrally with the fan cover, i.e. integrated.

[0004] From the DE 10 2005 031 197 A1 A drive is known in which a fan is provided for cooling a gear of the drive.

[0005] A power transmission device is known from DE 11 2014 000 834 T5.

[0006] A cooling arrangement for a transmission is known from DE 10 2008 017 755 A1.

[0007] From DE 10 2007 009 366 A1 is The closest state of the art is a fan wheel.

[0008] From the GB 436 416 A An air-cooled transmission unit is known.

[0009] From the US 4 872 502 A Air cooling for an enclosed gearbox is known.

[0010] From the DE 10 2005 031 197 A1 A drive with a fan is known.

[0011] From the US 2014 / 0 338 495 A1 A power transmission device is known.

[0012] From the US 2011 / 0 179 903 A1 A gearbox with a liquid cooler is known.

[0013] From the DE 11 2013 007 680 T5 A system for attaching an inner air deflector to an air deflector cap for electrical machines is known.

[0014] From the US 2011 / 179903 A1 A gearbox with a fan is known.

[0015] From the CN 203 394 862 U A two-part structure with recesses is known.

[0016] The invention is therefore based on the object of developing a gearbox with a fan arrangement, whereby a simple and cost-effective production should be achievable.

[0017] According to the invention, the object is achieved in the transmission according to the features specified in claim 1.

[0018] The advantage here is that although the cover parts of the fan cowl are held by the holding frame, the cover part functionally acts as an axial extension of the fan cowl and does not have to be held by the holding frame but is attached and held in place on the gearbox housing. Optionally, the cover part can be connected to one of the cover parts in order to achieve the best possible seal between the cover part and the fan cowl and to keep losses in the conveyed air flow to a minimum. However, this connection is not load-bearing, as otherwise the holding frame would have to exert excessive load-bearing forces and the load-bearing force for the cover part would have to be passed through the cover part. According to the invention, the cover part can be manufactured with very little mass and material and can therefore be supported by the holding frame without any special effort. The cover part can be attached to and supported on the gearbox housing by means of tabs. It is therefore not self-supporting.The disadvantage is that threaded holes must be drilled into the housing to attach the cover. However, the advantage is that the cover can be manufactured from thin sheet metal or plastic. Since the hood parts and the cover can even be manufactured as stamped and bent parts from sheet steel, a cost-effective design is possible. Attaching the cover to the housing and separating the cover from the hood also reduces the tendency to vibrate, thus increasing stability.

[0019] The cover directs a portion of the airflow produced by the fan along the transmission housing. This improves heat dissipation of the transmission. To this end, the cover is shaped in such a way that the cover, held by tabs attached to the transmission housing, directs the portion of the airflow between the transmission housing and the cover.

[0020] According to the inventionThe grille is formed from two grille sections, each grille section being connected to each of the two cover sections, in particular by means of screws. In particular, the first grille section is connected to both the first and second cover sections, and the second grille section is connected to both the first and second cover sections. The advantage here is that the stability of the fan cover is increased by the grille sections acting as connecting elements. This also suppresses resonant vibrations of the fan cover. However, the disadvantage is the complex assembly process.

[0021] In an advantageous embodiment, a surface area of ​​the gearbox housing connected to the tab is flat and thus encompassed by a first plane, wherein a connecting region of the cover part which touches the tab or which adjoins the tab is flat and is thus encompassed by a second plane, wherein the first plane has a non-zero angle to the second plane, in particular the normal direction of the first plane to the normal direction of the second plane, and in particular is or are not aligned parallel to one another. It is advantageous in this case that the tab can be designed as an angled part, so that a connection of the cover part to the housing is possible, even though the cover part is not aligned parallel to the surface area of ​​the housing. The tab bridges and thus connects the cover part to the housing, wherein in order to press the tab onto the housing a screw is screwed into a threaded hole in the housing and the head of the screw presses the tab onto the housing. The tendency to vibrate is thereby reduced.

[0022] In an advantageous embodiment, the tab is manufactured as a stamped and bent part, In particular, the tab is connected to the cover part by means of a screw whose screw head presses the cover part and the tab toward a nut into which the screw is screwed. The advantage here is that the tab can be manufactured as a separate sheet metal part, allowing the screw to be guided through a slotted hole in the tab, thus allowing for easy compensation of tolerances. This reduces the tendency to vibrate.

[0023] In another advantageous embodiment, the tab is formed integrally with the cover part, in particular as a single piece, in particular as a single piece, in particular as a bending region on the cover part. This is advantageous in that a further reduction in the tendency to vibrate and the number of parts can be achieved. However, the cover part must be manufactured with a low tolerance and / or with high quality.

[0024] In an advantageous embodiment, the tab is pressed against the housing by the head of a screw screwed into a threaded hole in the housing. This allows for a simple, cost-effective, load-bearing attachment of the cover part.

[0025] In an advantageous embodiment, the cover part is connected to the first hood part. This has the advantage that only a small portion of the airflow is lost and the tendency to oscillate can be reduced.

[0026] In an advantageous embodiment, the area covered by the cover part in the axial direction is adjacent to and / or spaced from the area covered by the first hood part in the axial direction. This is advantageous in that the tendency to vibration is reduced because the cover part and the first hood part are vibration-decoupled. Thus, the overall tendency to vibration is reduced.

[0027] In an advantageous embodiment, the grid is formed from two grid parts, the first dividing line of which is a straight line or is formed from two straight lines lying in alignment with one another, wherein the hood is formed from two hood parts, the second dividing line of which is a flat curve composed of straight line sections.

[0028] The advantage is that it allows for simple manufacturing, as the grille parts are much smaller than a single-piece grille. Likewise, the hood parts can be easily manufactured from a single sheet of metal by punching and bending.

[0029] Due to the non-parallel alignment of the two dividing lines to each other, increased stability can be achieved, particularly against mechanical vibrations.

[0030] In an advantageous embodiment, the grid parts are each polygonally shaped on their respective outer periphery, such that the contact surface between the respective grid part and the respective hood part is composed of flat surface pieces. This is advantageous because a stable connection between the grid parts and the hood parts can be established using screws, and resonance vibrations can be suppressed.

[0031] In an advantageous embodiment, the first dividing line and the axis of rotation of the driving shaft span a first plane, The second dividing line and the rotational axis of the input shaft define a second plane, the second plane being perpendicular to the first plane or at least at an angle between 30° and 90°. The advantage of this is that increased stability can be achieved and vibrations can thus be suppressed.

[0032] In an advantageous embodiment, the hood formed from the two hood parts is shaped such that the hood has an axially continuous recess, in particular one that is centrally located relative to the drive shaft. This is advantageous because the hood parts each have a low mass, and the two grille parts can be used as fan cover grilles. Thus, both the hood parts and the grille parts can be manufactured as stamped and bent parts, allowing for efficient utilization of the sheet metal during stamping.

[0033] In an advantageous embodiment, the hood parts, which are made of stamped and bent sheet metal, are provided with a respective tab region that projects into the recess, to which the first or second grille part is attached, in particular by means of screws. This is advantageous because a simple, secure attachment for the grille parts is achievable.

[0034] In an advantageous embodiment, a respective tab region protruding into the recess is formed on the hood parts, which are made from sheet metal as stamped and bent parts. The first or second grille part is fastened to said tab region, in particular by means of screws, with screw nuts welded to the respective tab region to provide threaded holes for the screws. This is advantageous in that the hood part can be produced easily and cost-effectively, and the grille parts only need to be screwed on.

[0035] In an alternative advantageous embodiment, a respective frame part welded to the inside of the respective hood part protrudes into the recess on the hood parts made of sheet metal as stamped and bent parts. The first or second grille part is attached to the frame part, in particular by means of screws, in particular with screw nuts welded to the frame part to provide threaded holes for the screws. The advantage here is that the hood parts are stiffened by the strut-like frame part and are thus impact-resistant.

[0036] In an advantageous embodiment, the recess is completely covered by the grille, in particular by both grille parts, in particular in such a way that the axially entering air flow passes through the grille. It is advantageous that the grille openings are so small that they provide protection against a human hand reaching through them.

[0037] In an advantageous embodiment, the two grid parts touch each other along the first dividing line or have a distance of less than 5 mm from each other.

[0038] In an advantageous embodiment, the two hood parts touch along the second dividing line or are separated by a distance of less than 5 mm. Advantageously, there is either contact along the dividing lines or, alternatively, only a very small distance, which prevents a human hand from reaching through.

[0039] In an advantageous embodiment, the airflow required by the fan impeller exits between the gearbox housing and the cover, particularly directed so that it flows along the gearbox housing. This is advantageous because the gearbox is cooled as effectively and evenly as possible.

[0040] In an advantageous embodiment, the cover has an irregularly polygonal shaped end face in the circumferential direction, in particular the radially outer periphery of the end face of the cover has an irregularly polygonal shape. This is advantageous because, although a circular fan is used for a cuboid-shaped gearbox, the air flow is nevertheless distributed as evenly as possible along the circumference of the gearbox.

[0041] In an advantageous embodiment, the hood parts and / or the grille parts are each manufactured as stamped and bent parts. This is advantageous because it allows for simple, cost-effective production.

[0042] In an advantageous embodiment, an intervention protection is attached to each hood part, in particular to the inner wall of each hood part, which is arranged between the hood part and the housing of the gearbox, The guard has continuous grille openings, in particular through which the air flow conveyed by the fan impeller flows. This is advantageous in that it also prevents interference against the direction of the air flow conveyed by the fan impeller. Furthermore, the guard is attached to the inner wall of the cover section. Thus, a direct connection to the gearbox is not necessary.

[0043] In an advantageous embodiment, each hood part has radially continuous recesses which are shaped as a slot, elongated hole or ellipse, wherein the longest extension of the respective recess is aligned in the axial direction.

[0044] This allows air to flow radially, especially when axial flow is hindered or prevented by objects or devices positioned close to the grille parts. This also provides protection against contact with rotating parts.

[0045] In an advantageous embodiment, each grille part has a uniform and / or regular, flat grille of recesses, particularly hexagonal openings, extending axially through the respective grille part. This is advantageous in that the largest possible air flow can be axially introduced with the lowest possible air resistance. The flow resistance generated by the respective grille part is preferably low. Nevertheless, contact protection against contact with rotating parts is achieved.

[0046] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art.

[0047] The invention will now be explained in more detail using schematic illustrations: In the Figure 1 A gearbox according to the invention with a fan arranged on the input side is shown in an oblique view. Figure 2 is in contrast to Figure 1 a first hood part 1 and a second grille part 4 are hidden. In the Figure 3 are in contrast to Figure 2The fan components located outside the gearbox housing 5 are shown exploded, showing a two-piece support frame. Figure 4 are in contrast to Figure 1 The fan components located outside the gearbox housing 5 are shown exploded. Figure 5 As a further example, a gearbox is shown in an oblique view. In the Figure 6 one of the two pieces of the holding frame 32 is shown in an oblique view.

[0048] As shown in the figures, the gearbox has an input shaft 6 which is rotatably mounted by means of bearings in a housing 5 of the gearbox.

[0049] A fan impeller 20 is non-rotatably connected to the input shaft 6 of the gearbox and surrounded by a cover assembly that is attached to a support frame 32 on the housing 5 of the gearbox. The support frame 32 is constructed in several pieces, in particular in two pieces, and is attached to the housing 5 by means of fastening screws.

[0050] The hood assembly comprises a first hood part 1 and a second hood part 2, both of which are screwed to the holding frame 32 by means of screws.

[0051] Each of the two hood parts (1, 2) covers a circumferential angle of 180° relative to the axis of rotation of the input shaft 6. The dividing line between the two hood parts (1, 2) runs vertically in the embodiment shown in the figures.

[0052] The two cover parts (1, 2) thus form a fan cover, which guides the air flow conveyed by the fan impeller 20 so that it flows out of the fan cover 20 along the housing 5. The housing 5 of the gearbox is roughly cuboid-shaped. However, since the fan impeller 20 is round, the fan cover formed by the two cover parts (1, 2), which are arranged as close as possible to one another or at least very close to one another, has a polygonal circumference. This means that the air flow flowing out between the fan cover and the housing 5 is as little dependent as possible on the circumferential angle. In other words, the air flow exiting the fan cover is distributed as evenly as possible across the circumferential directions. This allows for optimal cooling.The round fan wheel 20 preferably does not protrude at the corners of the cuboid, but only at straight side surfaces; however, the fan cover also protrudes at the corners and thus directs an escaping air flow even to the corner areas of the cuboid.

[0053] Each cover part 1, 2 is designed as a stamped and bent part, in particular bent, in such a way that it has an area on its circumference provided with recesses and thus permeable to air, which allows an air flow coming from the radial direction to enter the fan cover.

[0054] The radial direction refers to the axis of rotation of the driving shaft.

[0055] The hood formed from the two hood parts (1, 2) is shaped such that the hood has an axially continuous recess located centrally. Furthermore, the hood parts (1, 2), which are made of sheet metal as stamped and bent parts, have tab regions projecting into the recess, to which a first or a second grille part (3, 4) is attached, in particular by means of screws.

[0056] Thus, the recess is completely covered by the grille parts 3 and 4. The axially entering air flow passes through this fan grille thus formed.

[0057] To provide a threaded hole for screws connecting the grille parts (3, 4) to the tab areas of the hood parts (1, 2), screw nuts are welded to the tab areas. The grille parts (3, 4) can then be screwed on using screws that extend axially through a recess in the respective tab area and are screwed into the screw nuts, the screw heads of which press the respective grille part against the respective tab area.

[0058] The two grid parts 3 and 4 touch each other along a straight line or are separated by less than 5 mm along a straight line. This line is also referred to here as the first dividing line.

[0059] The first dividing line and the axis of rotation of the driving shaft form a first plane.

[0060] The first hood part 1 touches the second hood part 2 along a flat curve or has a distance of less than 5 mm along a flat curve. This flat curve is also referred to here as the second dividing line.

[0061] The second dividing line is composed of straight sections.

[0062] The second dividing line and the axis of rotation of the driving shaft form a second plane.

[0063] The second plane is not parallel to the first plane, but preferably perpendicular or at least has an angle between 30° and 90°.

[0064] This achieves increased stability, as the hood parts (1, 2) and the grille parts (3, 4) are made of stamped and bent sheet metal. The angle thus reduces or prevents the risk of resonance vibration.

[0065] The grille parts (3, 4) each have a preferably regular grid of continuous recesses (not shown in the figures). This allows an air flow to pass axially through and be drawn to the fan.

[0066] On the inside of the first hood part 1, an intervention guard 31 is arranged, through which the air flow conveyed by the fan exits and flows out from the first hood part 1 in such a way that it flows along the outside of the gearbox.

[0067] In addition, the first cover part 1 has a semicircular recess, so that a bearing cover section of a bearing cover covering the bearing of the input shaft, which bearing cover projects axially towards the recess, has a sufficiently large distance from the cover part 1, so that the air sucked in by the fan enters through the recess as evenly as possible around the circumference and thus also exits as evenly as possible around the circumference of the fan cover and thus the housing 5 is evenly cooled.

[0068] An anti-interference guard 31 is attached to the cover part 30. Alternatively, an anti-interference guard 31 can be attached to the inside of the second cover part 2, through which the air flow conveyed by the fan exits and flows out of the second cover part 2 in such a way that it flows along the outside of the gearbox.

[0069] As shown in the figures, the second cover part 2 also has a semicircular recess, so that the bearing cover section of a bearing cover covering the bearing of the input shaft, which section projects axially towards the recess, has a sufficiently large distance from the second cover part 2, so that the air sucked in by the fan enters through the recess as evenly as possible around the circumference and thus also exits as evenly as possible around the circumference of the fan cover and thus the housing 5 is evenly cooled.

[0070] However, the fan cover can also be attached to a different gearbox where the round bearing cover section is either missing or located further away. In this case, the recess on the first cover part 1 is closed by attaching a cover part 30, thus directing the airflow better and more evenly along the housing 5. Likewise, in this case, the recess on the second cover part 1 is closed by attaching another cover part 30, thus directing the airflow better and more evenly along the housing 5.

[0071] If a clutch or an electric motor is connected to the input shaft and arranged axially close to the fan cover in such a way that no air can flow axially, i.e. through the grille parts 3 and 4, it is possible, however, for air to flow radially through the cover parts 1 and 2 towards the fan.

[0072] Thus, the recesses of the respective air-permeable area of ​​the hood parts (1, 2) and the grille parts (3, 4) allow the air flow sucked in by the fan wheel to flow in from radial and axial directions.

[0073] The irregular polygonal shape of the fan cover's front face not only ensures even airflow distribution along the circumference, but also allows for easy production of the two-part fan cover as stamped and bent parts. The underside of the gearbox acts as a base or support surface and is not exposed to airflow.

[0074] The polygonal shape of the fan cover also allows the formation of flat tab areas arranged in a bent manner on the respective cover part, which enable easy fastening of the equally polygonal grille parts (3, 4).

[0075] The recesses of the air-permeable area on grille parts 3 and 4 are each hexagonal and evenly spaced from each other. Thus, the air-permeable area has a flat, regular grid of hexagonal recesses extending axially through the respective grille part (3, 4). This enables optimized utilization of the grille surface, in particular maintaining high stability despite allowing as much air passage as possible.

[0076] The hood parts 1 and 2, on the other hand, have radially continuous recesses shaped as slots, elongated holes, or ellipses, the longest extension of which is oriented in the axial direction. Since the recesses are arranged in the edge region of the hood parts (1, 2) adjacent to or facing the grille parts (3, 4), this elongated shape ensures the lowest possible flow resistance for radially inflowing air and sufficient stability for receiving and supporting the grille parts (3, 4) by the hood parts (1, 2).

[0077] To increase stability, cover parts 1 and 2 are designed to be as small as possible. However, to allow the air flow to flow as efficiently as possible in the axial direction along the gearbox housing, a cover part 7 is attached to the cover part 1 to guide the air flow. The cover part 7 extends along the housing and is also attached to the housing by means of tabs 9.

[0078] The cover part 7, like the hood part 1, is manufactured as a stamped and bent part, in particular as a sheet metal part. Tabs 9, which can also be manufactured as stamped and bent parts, serve to fasten the cover part 7 to the housing. It is important that the connecting area of ​​the cover part 7, i.e. the area of ​​the cover part 7 with which the tabs 9 are connected and / or in contact, is flat. This connecting area of ​​the cover part 7 is therefore arranged in a plane which is not parallel, i.e. which has a non-zero angle, to a flat surface area of ​​the gearbox housing. Thus, the connecting area does not lie flat against the surface area of ​​the gearbox housing, but only linearly when the two parts touch. Therefore, the tabs 9 bridge the non-zero angle existing between the surface area and the connecting area.

[0079] The support frame 32 is made of two pieces, each of which is designed as a stamped and bent part. The support frame 32 is fastened to the housing 5, in particular by means of screws screwed into threaded holes, the screw heads of which press the respective piece against the housing 5. On the other hand, both hood parts (1, 2) are connected to each of the pieces. Thus, the hood parts (1, 2) are supported, in particular held, by the support frame 32, which is fastened to the housing 5.

[0080] Each piece of the support frame 32 also has an air guide portion that protrudes axially, thus directing at least a portion of the air flow conveyed by the fan between the piece and the housing 5. Thus, a portion of the air flow flows between the air guide portion of the piece and the housing 5. The support frame 32 is attached to the housing 5, and thus the air guide portion is held in a cantilevered manner.

[0081] On the other hand, the cover part 7 is attached to the housing 5 by means of the tabs 9.

[0082] A sheet metal part 50 is attached to the hood parts (1, 2) so that the conveyed air flow can be directed along the housing 5.

[0083] In further embodiments, the tabs 9 are formed on the cover part 7 itself by being designed as a bent area of ​​the cover part 7. Thus, the tabs 9 do not have to be connected to the cover part 7, since they are formed integrally, i.e., as a single piece, on the cover part 7 itself and are bent such that they lie flat against the surface area of ​​the gearbox housing. By means of the screw head of a screw screwed into a threaded hole in the housing, the respective tab 9 is pressed against the gearbox housing. This achieves a simple and cost-effective connection, even though the area of ​​the cover part 7 adjacent to the tab 9 is not aligned parallel to the surface area of ​​the housing receiving the threaded hole.

[0084] The surface area is shown as a flat surface area 10 in the figures.

[0085] In the elliptical design, the main axis of the respective ellipse is aligned in the axial direction.

[0086] In further embodiments according to the invention, instead of the fan cover being divided into two parts, it is divided into multiple parts.

[0087] In further embodiments according to the invention, no tab areas are formed on the inside of the hood parts (1, 2), but rather a polygonally shaped frame part is welded to each of the hood parts (1, 2). The vertical projection of the frame part in the axial direction resembles a partial area of ​​a polygon. The originally flat frame part is bent at each corner of the polygonal partial area so that the respective side of the frame part arranged between each two adjacent corners of the polygon is flat and oriented perpendicular to the hood part. The normal direction of the plane receiving the polygon is oriented in the axial direction. This stabilizes the respective hood part (1, 2). Screw nuts are welded to the frame parts to provide a threaded hole for screws that connect the grille parts (3, 4) to the hood parts (1, 2).Thus, the grid parts (3, 4) can then be screwed on by means of the screws which pass axially through a recess in the respective frame part and are screwed into the screw nuts, the screw heads of which press the respective grid part against the respective frame part. List of reference symbols

[0088] 1 first hood part 2 second hood part 3 first grille part 4 second grille part 5 housing 6 driving shaft 7 cover part 8 bearing cover 9 tab 10 flat surface piece 20 fan wheel 30 cover part 31 protection guard 32 holding frame 50 sheet metal part 60 air guide area of ​​a piece of the holding frame 32

Claims

1. A gear unit with fan assembly, wherein the fan assembly has a fan impeller (20), a cowl, in particular therefore a fan cowl, and a grille, wherein the fan impeller (20) is connected non-rotatably to the input shaft (6) of the gear unit, wherein the cowl is fastened to a holding frame (32) embodied in particular in multiple pieces which is fastened to the housing (5) of the gear unit, wherein the cowl is formed of two cowl parts (1, 2), characterised in that a covering part (7, 30) adjoins a first one of the cowl parts (1, 2), which covering part is supported and / or held by at least one tab (9) which is connected to the housing (5) of the gear unit and / or is fastened to this housing (5), with the region covered by the covering part (7, 30) in the axial direction being spaced apart from or adjoining the region covered by the first cowl part (1) in the axial direction, with the axial direction being the direction of the axis of rotation of the input shaft (6), with the cowl and the covering part (7, 30) being arranged and shaped such that a portion of the air flow conveyed by the fan impeller (20) is conducted by the cowl and the covering part (7, 30) between the housing (5) of the gear unit and the covering part (7, 30), with the grille being formed of two grille parts (3, 4), with an angle-at-circumference region covered by the first grille part (3) in the circumferential direction adjoining, but in particular adjoining in a non-overlapping manner, the angle-at-circumference region covered by the second grille part in the circumferential direction, and with the angle-at-circumference region covered by the first cowl part (1) in the circumferential direction adjoining, but in particular adjoining in a non-overlapping manner, the angle-at-circumference region covered by the second cowl part (2) in the circumferential direction, with the angle-at-circumference region covered by the first grille part (3) in the circumferential direction overlapping with the angle-at-circumference region covered by the first cowl part (1), with each grille part (3, 4) being connected, in particular connected by means of screws, to each of the two cowl parts (1, 2), i.e. the first grille part (3) is connected both to the first and to the second cowl part (2) and the second grille part is connected both to the first and to the second cowl part (2).

2. A gear unit according to claim 1, characterised in that a surface region, which is connected to the tab (9), of the housing (5) of the gear unit is formed flat and hence is encompassed by a first plane, with a connection region of the covering part (7, 30) which contacts the tab (9) or adjoins the tab (9) being formed flat and hence being encompassed by a second plane, with the first plane in relation to the second plane, in particular the normal direction of the first plane in relation to the normal direction of the second plane, having a non-vanishing angle, in particular therefore being oriented not parallel to each other.

3. A gear unit according to one of the preceding claims, characterised in that the tab (9) is produced as a stamped and bent part, in particular with the tab (9) being connected to the covering part (7, 30) by means of a screw, the screw head of which presses the covering part (7, 30) and the tab (9) towards a nut into which the screw is screwed, or in that the tab (9) is formed in one piece, in particular in one part, with the covering part (7, 30), in particular is formed in one piece, in particular in one part, as a bending region on the covering part (7, 30).

4. A gear unit according to one of the preceding claims, characterised in that the tab (9) is pressed against the housing (5) by a screw head of a screw screwed into a threaded bore in the housing (5).

5. A gear unit according to one of the preceding claims, characterised in that the covering part (7, 30) is connected to the first of the two cowl parts (1, 2) and / or in that the region covered by the covering part (7, 30) in the axial direction adjoins and / or is spaced apart from the region covered by the first cowl part (1) in the axial direction.

6. A gear unit according to one of the preceding claims, characterised in that the grille parts (3, 4) are each formed as a polygon such that the contacting face between the respective grille part (3, 4) and the respective cowl part (1, 2) in each case is composed of flat face pieces (10), in particular so that a stable connection can be produced by means of screws.

7. A gear unit according to one of the preceding claims, characterised in that between the two grille parts (3, 4) a first parting line is formed as a straight section or as two straight sections which lie flush with each other, with between the two cowl parts (1, 2) a second parting line being formed as a plane curve composed of straight section portions, with the first parting line and the axis of rotation of the input shaft (6) spanning a first plane, with the second parting line and the axis of rotation of the input shaft (6) spanning a second plane, with the second plane being oriented perpendicularly or at least being at an angle of between 30° and 90° to the first plane.

8. A gear unit according to one of the preceding claims, characterised in that the cowl which is formed of the two cowl parts (1, 2) is shaped such that the cowl has an axially continuous recess, in particular which is arranged centrally relative to the input shaft (6).

9. A gear unit according to one of the preceding claims, characterised in that on the cowl parts (1, 2) which are produced as stamped and bent parts from metal sheet there is formed a respective tab region which projects into the recess, to which tab region the first or the second grille part (3, 4) is fastened, in particular is fastened by means of screws, in particular with screw nuts being welded on the respective tab region to provide threaded bores for the screws.

10. A gear unit according to one of the preceding claims, characterised in that on the cowl parts (1, 2) which are produced as stamped and bent parts from metal sheet a respective frame part welded on the inside of the respective cowl part (1, 2) projects into the recess, to which frame part the first or the second grille part (3, 4) is fastened, in particular is fastened by means of screws, in particular with screw nuts being welded on the frame part to provide threaded bores for the screws.

11. A gear unit according to one of the preceding claims, characterised in that the recess [is] covered in particular completely by the grille, in particular by the two grille parts (3, 4), in particular such that the axially entering air flow passes through the grille.

12. A gear unit according to one of the preceding claims, characterised in that the two grille parts (3, 4) contact each other along the first parting line or are at a distance of less than 5 mm from each other.

13. A gear unit according to one of the preceding claims, characterised in that the two cowl parts (1, 2) contact each other along the second parting line or are at a distance of less than 5 mm from each other, and / or in that the air flow conveyed by the fan impeller (20) emerges between the housing (5) of the gear unit and the cowl, in particular directed such that it flows along the housing (5) of the gear unit, and / or in that the cowl has an end face shaped as an irregular polygon in the circumferential direction, in particular the radially outer periphery of the end face of the cowl is shaped as an irregular polygon, and / or in that the cowl parts (1, 2) and / or the grille parts (3, 4) are each manufactured as stamped and bent parts, and / or in that to each cowl part (1, 2), in particular to the inner wall of each cowl part, there is fastened a protective guard (31) which is arranged between the respective cowl part (1, 2) and housing (5) of the gear unit, with the protective guard (31) having continuous grille openings, in particular and has the air flow conveyed by the fan impeller (20) flowing through it.

14. A gear unit according to one of the preceding claims, characterised in that each cowl part (1, 2) has radially continuous recesses which are formed as slots, elongate holes or ellipses, with the longest extent of the respective recess in each case being oriented in the axial direction.

15. A gear unit according to one of the preceding claims, characterised in that each grille part (3, 4) has a uniform and / or regular flat grille of in particular hexagonal recesses, in particular grille openings, which pass axially through the respective grille part (3, 4).