Device, system and method for sealing a gearbox against a machine

Abstract

A shaft seal element for sealing a gearbox against a machine comprises a housing. The housing of the shaft seal element forms an interference fit on its outer circumferential surface. The interference fit has at least a partial coating and at least one groove for positioning the shaft seal element within the assembly.

Description

[0001] The present invention relates to a device, a system and a method for sealing a gearbox against a machine, in particular a shaft seal element with a groove on the press fit for receiving particles that shear off during the assembly of the shaft seal element. State of the art

[0002] A machine, for example an electric machine such as an electric motor, is regularly flanged to a gearbox, or vice versa, to form a system. The machine can be connected to the gearbox, for example, via a system with one or more bearings and a housing.

[0003] In the case of a dry-running electric machine, it must be ensured that no fluids can enter the interior of the electric machine. For example, it must be ensured that no transmission oil can flow from the gearbox into the electric machine when the system is in a ready-to-use state or in operation.

[0004] For this purpose, a shaft seal element can be integrated into the assembly, which, during operation, is in direct contact with a rotor shaft of the electric machine. The shaft seal element is intended to ensure a seal between the machine and gearbox for as long as possible, ideally for the entire service life of the system. During assembly, the shaft seal element is therefore pressed into position to form an interference fit with the housing of the assembly.

[0005] With conventional shaft seals, whose housings in the area of ​​the press fit on the outer circumference are made of, for example, aluminum or steel, especially with shaft seals with a sealing lip made of, for example, polytetrafluoroethylene (PTFE), the problem often arises during assembly that dry pressing into the housing of the assembly is not possible or only possible with difficulty, because, for example, excessively high pressing forces would be required and / or dry pressing would lead to an increased probability of leaks in the press fit.

[0006] A conventional measure to address this problem is a coating on the outer circumference of the shaft seal element, for example, an elastomer coating. However, at least parts of the coating can be sheared off during the pressing process, leaving particles in the gearbox and / or machine after installation, which can shorten the system's service life.

[0007] DE 10 2019 214 611 A1 discloses a shaft sealing element which is arranged in a one- or multi-part housing of an electric machine and a gearbox, runs on a rotor shaft and separates one side of the gearbox from one side of the electric machine. The shaft sealing element has a reservoir which collects lubricating medium when the rotor shaft rotates in a direction opposite to a preferred direction of rotation.

[0008] DE 10 2020 207 991 A1 discloses an electric drive with an electric machine comprising a rotor shaft. The rotor shaft is supported at a first bearing point and at a second bearing point in a housing. A sealing ring in the form of a radial shaft seal can be arranged within an axial distance between the two bearing points to separate a dry area of ​​the electric machine from a wet area.

[0009] DE 10 2020 215 975 A1 discloses a transmission suitable for forward and reverse driving. The transmission comprises a housing formed from housing halves joined along a parting line, and a differential gear. A collection device for a lubricating medium is provided inside the housing.

[0010] DE 10 2021 204 795 A1 discloses a bearing arrangement of an axle module with an electric machine and a gearbox with a gearbox input shaft supported by multiple bearings. The bearing arrangement in the gearbox is designed as a first X-arrangement of a cover-side bearing and a housing-side bearing. Starting from a bearing seat of the cover-side bearing, the gearbox input shaft has essentially increasing functional diameters that extend towards the center of the gearbox input shaft. Disclosure of the invention

[0011] The invention provides a device, a system and a method for sealing a gearbox against a machine with the features of the independent claims.

[0012] Preferred embodiments are the subject of the respective dependent claims.

[0013] The invention enables the assembly of a shaft sealing element without generating particles in the gearbox or electric machine, and thus extends the service life of a system comprising the gearbox and the electric machine.

[0014] According to a first aspect, the invention relates to a shaft sealing element for sealing a gearbox against a machine with a housing, wherein the housing of the shaft sealing element forms a press fit on its outer circumferential surface, wherein the press fit has at least a coating and at least one groove for placing the shaft sealing element in a composite.

[0015] According to a further development, the press fit between the at least one groove and an edge of the shaft sealing element has at least one clearance fit, wherein the at least one clearance fit has an outer diameter that is smaller than an outer diameter in the area of ​​the remaining press fit in order to prevent shearing of particles in the area of ​​the at least one clearance fit when placing the shaft sealing element in the assembly.

[0016] According to further training, the press fit in the area between the at least one groove and the edge of the shaft sealing element has no coating.

[0017] According to further training, the groove is configured to accommodate a sealing ring.

[0018] According to further training, the press fit in the area between the at least one groove and the edge of the shaft sealing element has a sealing lip which is configured to prevent particles from being flushed out of the groove.

[0019] According to further training, at least one groove in a cross-section has a triangular shape in order to increase the volume for receiving sheared particles.

[0020] According to further training, the housing of the shaft sealing element is made of aluminum or steel.

[0021] According to further training, the coating is made of an elastomer.

[0022] According to a second aspect, the invention relates to a system with a composite, wherein the composite comprises a shaft sealing element as described above.

[0023] According to a first aspect, the invention relates to a method for sealing a gearbox against a machine by means of a shaft sealing element as described above, wherein the method comprises at least one or more of the following steps: connecting the machine to the assembly; pressing the shaft sealing element into a housing of the assembly; connecting the gearbox to the assembly. Brief description of the drawings

[0024] It shows: Fig. 1 a schematic representation of a cross-section of an exemplary system comprising an electric machine, a gearbox and a combination with a shaft sealing element according to an embodiment of the invention; Fig. 2 a schematic representation of a cross-section of an exemplary shaft sealing element with a groove according to an embodiment of the invention; Fig. 3 a schematic representation of a cross-section of an exemplary shaft sealing element with a groove and a clearance fit according to a further embodiment of the invention; and Fig. 4 A schematic representation of an exemplary method for sealing a gearbox against a machine according to an embodiment of the invention.

[0025] In all figures, identical or functionally equivalent elements and devices are designated with the same reference numerals. The numbering of process steps serves for clarity and generally does not imply a specific chronological order. In particular, several process steps can be performed simultaneously. Description of the exemplary implementations

[0026] Fig. Figure 1 shows a schematic representation of a cross-section of an exemplary system 1000 with an electric machine 1100, a gearbox 1200 and a combination 1300 with a shaft sealing element 1340 according to an embodiment of the invention.

[0027] The electric machine 1100 comprises a rotor shaft 1110 and a stator 1120. The rotor shaft may have a bore 1112 with a splined connection 1111 to connect the rotor shaft 1110 to a splined connection 1211 of an input shaft 1210 of the gearbox 1200. The gearbox 1200 may further comprise a pinion 1220 and one or more gears 1230.

[0028] The electric machine 1100 and the gearbox 1200 can be connected to each other via an assembly 1300. The assembly 1300 comprises a housing 1310. The assembly 1300 can have a machine bearing 1320 and / or a gearbox bearing 1330. The rotor shaft 1110 can be supported on the machine bearing 1320. The input shaft 1210 can be supported on the gearbox bearing 1330. The machine bearing 1320 and / or the gearbox bearing 1330 can be arranged in the housing 1310. The housing 1310 can be a single piece or multiple pieces.

[0029] The assembly includes a shaft seal element 1340, which separates a gearbox side from a machine side. The machine side can also be referred to as the air side. The gearbox side can also be referred to as the oil side. During assembly, a shaft seal element 1340 can be pressed into the assembly 1300 from either the machine side or the gearbox side to firmly position the shaft seal element 1340 within the assembly 1300.

[0030] As follows with reference to the Fig. 2 and Fig. As shown and described in detail in Figure 3, the shaft seal element 1340 comprises a coating and one or more grooves in the area of ​​its press fit on the outer circumference. The one or more grooves are configured to collect particles that form during the assembly of the shaft seal element 1340 in the assembly 1300.

[0031] Fig. Figure 2 shows a schematic representation of a cross-section of an exemplary shaft sealing element 2340 with a groove 2343 according to an embodiment of the invention in a housing 2310 of a composite (see Figure 2). Fig. 1).

[0032] The housing of the shaft seal element 2340 comprises a coating 2341 in the area of ​​the press fit 2342 of the shaft seal element 2340, i.e., on its outer circumference. The housing of the shaft seal element 2340 can be made of, for example, aluminum or steel. Other materials are also possible. The coating 2341 can, for example, comprise an elastomer or be made entirely of one.

[0033] In the area of ​​the press fit 2342, the shaft seal 2340 comprises one or more grooves 2343. The one or more grooves 2343 can be formed with respect to the center of the shaft seal 2340 on a machine side and / or on a gearbox side to allow the collection of abraded particles during installation of the shaft seal 2340 from the machine side and / or the gearbox side. The one or more grooves 2343 can be formed circumferentially around the shaft seal 2340.

[0034] An area between a groove and an edge of the shaft sealing element 2340, wherein the groove may be the groove closest to the edge, may not have a coating in order to prevent shearing of particles between this groove and the edge during assembly.

[0035] A groove 2343 can have the same depth or different depths in one direction of rotation, depending on a rotation angle (not shown). The cross-sectional shape of a groove 2343 can be configured to receive particles while maximizing the contact area between the housing 2310 of the composite and the housing of the shaft seal element 2340, for example, a triangular or bottle shape. The shape can be inclined relative to the insertion direction to facilitate the reception of sheared particles.

[0036] A swirl structure 2345 can be formed on the inner circumference of the shaft sealing element 2340. The swirl structure 2345 can have an arrow shape and a width as shown. The swirl structure 2345 can serve to pump oil back into the gearbox (see figure). Fig. 1) The shaft sealing element 2340 can further comprise a recess 2346, with a valley point 2347, the lowest point of which is to retain oil in the gearbox by utilizing centrifugal force.

[0037] Fig. Figure 3 shows a schematic representation of a cross-section of an exemplary shaft sealing element 3340 with a groove 3343 and a clearance fit 3344 according to a further embodiment of the invention in a housing 3310 of a composite (see Figure 3). Fig. 1).

[0038] The housing of the shaft seal element 3340 comprises a coating 3341 in the area of ​​the press fit 3342 of the shaft seal element 3340, i.e., on its outer circumference. The housing of the shaft seal element 3340 can be made of, for example, aluminum or steel. Other materials are also possible. The coating 3341 can, for example, comprise an elastomer or be made entirely of one.

[0039] In the area of ​​the press fit 3342, the shaft seal element 3340 comprises one or more grooves 3343. The one or more grooves 3343 can be formed with respect to the center of the shaft seal element 3340 on a machine side and / or on a gearbox side to allow the collection of abraded particles during installation of the shaft seal element 3340 from the machine side and / or the gearbox side. The one or more grooves 3343 can be formed circumferentially around the shaft seal element 3340.

[0040] A groove 3343 can have the same depth or different depths in one direction of rotation, depending on a rotation angle (not shown). The cross-sectional shape of a groove 3343 can be configured to receive particles while maximizing the contact area between the housing 3310 of the composite and the housing of the shaft seal element 3340, for example, a triangular or bottle shape. The shape can be inclined relative to the press-fit direction to facilitate the reception of sheared particles.

[0041] In the area of ​​the press fit 3342, the shaft seal element 3340 may further comprise one or more clearance fits 3344. The one or more clearance fits 3344 may be formed on an edge of the shaft seal element 3340 on a machine side and / or on a gearbox side to prevent shearing of particles in the area of ​​the one or more clearance fits 3344. In other words, an outside diameter in the area of ​​the one or more clearance fits 3344 may be smaller than the outside diameter in the area of ​​the remaining press fit 3342. For example, the outside diameter in the area of ​​the clearance fits 3344 may be at least 1 mm smaller than the outside diameter in the area of ​​the remaining press fit 3342.

[0042] Coating the shaft sealing element 3340 on its outer circumference can be facilitated by a clearance fit 3344, since masking the outer circumference of the shaft sealing element 3340 in the area between an outer groove and an edge of the shaft sealing element 3340 is no longer necessary.

[0043] Alternatively or additionally to coating the area between the outer groove and the edge of the shaft seal element 3340, a flexible sealing lip can be injection-molded, pressed on, and / or clamped in a clearance fit to prevent particles from being washed out of the groove. The flexible sealing lip can be made, for example, of an elastomer or a thermoplastic.

[0044] According to a further embodiment, a groove, e.g., a groove of one or more grooves 2343 and / or 3343, can be configured as with reference to the Fig. 2 and Fig. 3 described, include a sealing ring, e.g. an O-ring, to further increase the tightness of the shaft sealing element on its outer circumferential surface.

[0045] Fig. Figure 4 shows a schematic representation of an exemplary method 4000 for sealing a gearbox against a machine according to an embodiment of the invention. The method 4000 comprises at least one or more steps of connecting 4100 a machine to a composite; pressing 4200 a shaft sealing element as described above into a housing of a composite; and / or connecting 4300 a gearbox to a composite.

[0046] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope specified by the claims, a multitude of modifications are possible that fall within the bounds of what is considered skilled in the art. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 214 611 A1

[0007] DE 10 2020 207 991 A1

[0008] DE 10 2020 215 975 A1

[0009] DE 10 2021 204 795 A1

[0010]

Claims

[1] Shaft sealing element (1340; 2340, 3340) for sealing a transmission (1200) with respect to a machine (1100) with: a housing, wherein the housing of the shaft sealing element (1340; 2340, 3340) forms a press fit (2343; 3342) on its outer circumferential surface, wherein the press fit (2343; 3342) at least partially has a coating (2341; 3341) and at least one groove (2343; 3343) for placing the shaft sealing element (1340; 2340, 3340) in a composite (1300). [2] Shaft sealing element (1340; 2340, 3340) according to claim 1, wherein the press fit (2343; 3342) between the at least one groove (2343; 3343) and an edge of the shaft sealing element (1340; 2340, 3340) has at least one clearance fit (3344), wherein the at least one clearance fit (3344) has an outer diameter which is smaller than an outer diameter in the region of the remaining press fit (2343; 3342) in order to prevent shearing off of particles in the region of the at least one clearance fit (3344) when placing the shaft sealing element (1340; 2340, 3340) in the composite (1300). [3] Shaft sealing element (1340; 2340, 3340) according to claim 1 or 2, wherein the press fit (2343; 3342) has no coating (2341; 3341) in the region between the at least one groove (2343; 3343) and the edge of the shaft sealing element (1340; 2340, 3340). [4] Shaft sealing element (1340; 2340, 3340) according to any one of claims 1 to 3, the groove (2343; 3343) is configured to receive a sealing ring. [5] Shaft sealing element (1340; 2340, 3340) according to any one of claims 2 to 4, wherein the press fit (3342) in the region between the at least one groove (2343; 3343) and the edge of the shaft sealing element (1340; 2340, 3340) has a sealing lip which is configured to prevent particles from being flushed out of the groove (2343; 3343). [6] The shaft sealing element (1340; 2340, 3340) according to any one of claims 1 to 5, wherein the at least one groove (2343; 3343) has a triangular shape in a cross section to increase a volume for receiving sheared particles. [7] Shaft sealing element (1340; 2340, 3340) according to any one of claims 1 to 6, wherein the housing of the shaft sealing element (1340; 2340, 3340) is formed of aluminum or steel. [8] Shaft sealing element (1340; 2340, 3340) according to any one of claims 1 to 7, wherein the coating (2341; 3341) is formed from an elastomer. [9] System (1000) comprising a composite (1300), the composite comprising a shaft sealing element (1340; 2340, 3340) according to any one of claims 1 to 8. [10] Method (4000) for sealing a transmission (1200) from a machine (1100) by means of a shaft sealing element (1340; 2340, 3340) according to any one of claims 1 to 8, wherein the method comprises at least one or more of the following steps: Connecting (4100) the machine (1100) to the assembly (1300); Pressing (4200) the shaft sealing element (1340; 2340, 3340) into a housing (1310; 2310; 3310) of the composite (1300); Connecting (4300) the gearbox (1200) to the assembly (1300).

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