Housing part for a gearbox with improved bearings for gear shafts

Abstract

A housing part (7, 7a..7f) for a transmission (3) is specified, which comprises a base part (8, 8a..8f) with a recess or depression (B). The housing part (7, 7a..7f) further comprises a one-piece bearing holder (9, 9a..9f) arranged in the recess or depression (B). In one case a), a plurality of rolling bearings (10) for transmission shafts (17, 19) of the transmission (3) are accommodated in the bearing holder (9, 9a..9f). In one case b), the bearing holder (9, 9a..9f) forms a plurality of bearing shells (C), which each serve as a rolling surface for rolling elements (22) of a respective rolling bearing (10) for a respective transmission shaft (17, 19) of the transmission (3). Furthermore, a gear (3) with such a housing part (7, 7a..7f) is specified, which has a plurality of rolling bearings (10) accommodated in the bearing holder (9, 9a..9f) and a plurality of gear shafts (16, 19) rotatably mounted in the rolling bearings (10) with gear wheels (14, 15, 17, 18) arranged thereon.In addition, an electric geared motor (1) with such a transmission (3), a vehicle (25) with such an electric geared motor (1) and a method for producing such a housing part (7, 7a..7f) are specified.

Description

TECHNICAL FIELDThe invention relates to a housing part for a transmission, which comprises a base part which has a recess or depression. The invention further relates to a transmission comprising a housing with such a housing part, a plurality of rolling bearings and a plurality of transmission shafts rotatably mounted in the rolling bearings and having gearwheels arranged thereon. The invention furthermore relates to an electric geared motor having an electric motor and a transmission of the above-mentioned type coupled thereto, and to a vehicle having such an electric geared motor which is provided for driving the vehicle. Finally, the invention relates to a method for producing a housing part of the aforementioned type.PRIOR ARTSuch a housing part, such a transmission, such an electric machine, such a vehicle and such a production method are fundamentally known from the prior art. It is problematic here that the forces acting on the shafts cause deformations of the housing in which the bearings for the shafts are arranged. The deformations can lead to variances in the distance and position of the shafts to one another and thus to non-optimum function of the transmission and increased sound emission.DISCLOSURE OF THE INVENTIONIt is therefore an object of the invention to specify an improved housing part of a transmission, an improved transmission, an improved electric machine, an improved vehicle having an electric machine and an improved production method for a housing part of a transmission.In particular, an optimum function of the transmission with low sound emission is to be achieved.The object of the invention is achieved with a housing part of the type mentioned at the beginning, which comprises a one-piece bearing holder arranged in the recess or depression, a) in which a plurality of rolling bearings for gear shafts of the gear are accommodated, or b) which forms a plurality of bearing shells, which each serve as a rolling surface for rolling bodies of one rolling bearing each for one gear shaft of the gear.Furthermore, the object of the invention is achieved with a transmission which comprises a housing with a housing part of the above-mentioned type, and a plurality of rolling bearings which are accommodated in the bearing holder and a plurality of transmission shafts which are rotatably mounted in the rolling bearings and have gearwheels arranged thereon.In addition, the object of the invention is achieved with an electric geared motor which comprises an electric motor and a gear of the above-mentioned type coupled thereto.In addition, the object of the invention is achieved with a vehicle having an electric machine of this type which is provided for driving the vehicle.Finally, the object of the invention is achieved with a method for producing a housing part for a transmission, which comprises the following steps:providing a base part which comprises a recess or depression; andarranging a one-piece bearing holder in the recess or depression of the base part, wherein a) a plurality of rolling bearings for gear shafts of the gear are accommodated in the bearing holder, or b) the bearing holder forms a plurality of bearing shells, which each serve as a rolling surface for rolling bodies of a respective rolling bearing for a respective gear shaft of the gear.The proposed measures make it possible to provide different part properties for the base part and the bearing holder, in particular different material properties, which are specifically aligned with the respective requirements. For example, the base part can be soft in comparison to the bearing holder. For example, ribbing otherwise necessary for a transmission housing can be made more tender or even omitted, since forces acting relatively between the transmission shafts and impressed into the roller bearings are absorbed by the bearing holder itself.In particular, in the bearing holder, in case a) at least three rolling bearings or in case b) bearing shells of at least three rolling bearings can be provided.The transmission can be designed, for example, as a spur gear transmission, in particular as a helical spur gear transmission. In one embodiment, a bearing retainer is provided only at one end of the gear shafts. However, it is advantageous if one bearing holder is provided at one end of the transmission shafts. The bearings arranged in a bearing holder can be arranged in a single plane, but they can also be offset axially with respect to one another.Further advantageous embodiments and developments of the invention are evident from the dependent claims and from the description taken together with the figures.It is advantageous if the base part is made of a first material and the bearing holder is made of a second material, wherein the strength of the second material is above the strength of the first material. The first material and / or the second material can be a metal in particular. The first material and / or the second material can, however, also be a plastic. The materials can be combined as desired, so that the following combinations are conceivable for the first material and second material: metal / metal, metal / plastic, plastic / metal, plastic / plastic. Suitable plastics for the base part and the bearing holder are, in particular, fiber-reinforced plastics. As fibers, for example, glass fibers, aramid fibers, Kevlar fibers or carbon fibers can be used. The fibers can be processed, for example, in the form of woven fabrics, knitted fabrics, braids or fiber mats.It is favorable if the first material is an aluminum alloy and the second material is steel. Stainless steel can be provided in particular as the steel, but the use of a stainless steel is also conceivable. Because the gear shafts and the gears seated thereon are usually also made of steel, the same coefficient of thermal expansion results for the bearing holder, the gear shafts and the gears, whereby the axial distance and the diameter of the pitch circles also remain constant, regardless of the selection of the first material. A hot forming plate can be provided in particular for the second material. Furthermore, the bearing holder can be designed as a stamped part or stamped and bent part.It is furthermore advantageous if a material thickness of the base part at a distance of 0 to 40 mm from the bearing holder is not more than 20% above a material thickness of the base part at a distance of >40 mm from the bearing holder. According to the prior art, gear housings in which rolling bearings are embedded have increased material thicknesses in the region of these bearings in order to hold the rolling bearings securely and to be able to absorb the forces occurring during operation of the gear. However, this also increases the risk for voids if the transmission housing is cast. By providing a bearing holder, on the other hand, the material thickness of the base part does not need to be significantly increased even in the vicinity of the bearing holder, whereby the risk for voids is avoided or at least significantly reduced. In particular, the proposed measures can be used if the strength of the bearing holder is above the strength of the base part. Further preferred distance ranges instead of 0 to 40 mm / >40 mm are 0 to 30 mm / >30 mm and 0 to 20 mm / >20 mm.It is advantageous if the bearing holder is coated with a plastic on all sides or only on a surface not covered by the base part. As a result, the bearing holder can be well protected from corrosion, for example. In particular, the strength of the second material can be above the strength of the plastic of the coating. In particular, the modulus of elasticity of the second material can be above the modulus of elasticity of the plastic of the coating.It is particularly advantageous if an intermediate layer made of a plastic is provided between the base part and the bearing holder, wherein the intermediate layer satisfies the condition in a temperature range from -50° to 200° C., wherein α 1 is the coefficient of thermal linear expansion of the first material, α 2 is the coefficient of thermal linear expansion of the second material and α 3 is the coefficient of thermal linear expansion of the intermediate layer, wherein d is the greatest expansion of the bearing holder and wherein c is a thickness of the intermediate layer. In other words, the thickness of the intermediate layer is selected such that the intermediate layer always connects the base part and the bearing holder in a temperature range of -50° to 200° C. That is, the bearing holder does not loosen even with increasing temperature. The thickness c is here significantly greater than a size difference in the case of conventional clearance fits and is in particular in a range from 0.5 mm to 2 mm.It is also particularly advantageous if an intermediate layer made of a pre-compressed plastic is provided between the base part and the bearing holder, wherein the intermediate layer satisfies the condition in a temperature range from -50° to 200° C., wherein α 1 is the coefficient of thermal linear expansion of the first material and α 2 is the coefficient of thermal linear expansion of the second material, wherein E is the compressive modulus of elasticity of the intermediate layer and wherein σ 20°C is the compressive stress prevailing in the intermediate layer at room temperature. In other words, the thermally caused variation of the compressive stress in the intermediate layer is not more than 10%. Yes applies to thisIn order to generate the compressive stress at room temperature necessary for holding the bearing part, it can be provided for the production method that the intermediate layer is precompressed in accordance with the above condition during embedding of the bearing holder in the recess or depression of the base part. In this way, too, loosening of the bearing holder as the temperature rises can be prevented.It is also particularly advantageous if the second material is stainless steel and if an intermediate layer of rust with a thickness of at least 50 μm is provided between the base part and the bearing holder in the unused state. In this variant, rust is intentionally produced in order to ensure the anchoring of the bearing holder in the base part. Specifically, the intermediate layer can be made of rust after the bearing holder is embedded in the recess or depression of the base part. For example, the intermediate layer can be produced in a targeted manner by introducing an electrolyte into a gap between the bearing holder and the base part and / or by applying an electrical voltage between the bearing holder and the base part.In one embodiment variant of the housing part, the bearing holder is detachably embedded in the recess or depression of the base part. As a result, the bearing holder can easily be replaced if necessary, for example if it is broken. However, advantages also result if a transmission is reconstructed only slightly enough that the base part can be used further. Adaptation to the modified construction can then be effected by simple replacement of the bearing holder. The term "releasable" in the given context means in particular that the bearing holder can be separated from the base part in a non-destructive manner without heating the housing above a temperature of 200° C. In other words, this means that a bearing holder detached from the base part can be arranged again in the recess or depression of the base part without further measures.In another embodiment variant of the housing part, the bearing holder is non-detachably embedded in the recess or depression of the base part. The term "non-detachable" in the given context means in particular that the bearing holder cannot be separated from the base part without destruction, without heating the housing above a temperature of 200° C. In other words, this means that a bearing holder detached from the base part cannot be permanently and non-detachably embedded again in the recess or depression of the base part without further measures. In particular, the bearing holder can be pressed, cast or glued into the base part.It is furthermore particularly advantageous if a lubricant channel for at least one of the rolling bearings is provided between the bearing holder and the base part, between the bearing holder and a plastic coating of the above-mentioned type, between the bearing holder and an intermediate layer of the above-mentioned type, between the base part and a plastic coating of the above-mentioned type, or between the base part and an intermediate layer of the above-mentioned type. In this way, the rolling bearings can be supplied with a lubricant during operation of the transmission. For example, the lubricant channel can be produced during casting of the base part or the bearing holder or during injection molding of the plastic coating or the intermediate layer, in particular using a lost core. In particular, lubricant channels can be provided for all rolling bearings arranged in the bearing holder.Finally, it is particularly advantageous if an intermediate layer made of a plastic is provided between the base part and the bearing holder, the damping and spring constant of which intermediate layer is matched to a resonant frequency of the transmission or to a resonant frequency of the electric geared motor. As a result, the intermediate layer also serves to suppress undesired noises.BRIEF DESCRIPTION OF THE FIGURESExemplary embodiments of the invention are illustrated by way of example in the appended schematic figures. The following are shown: FIG. 1 is a half-section of an exemplary electric geared motor; FIG. 2 is an exploded view of a housing part with bearing holder; FIG. 3 shows the housing part from FIG. 2 in the assembled state; FIG. 4 shows a housing part in section with an approximately constant material thickness; FIG. 5 shows a housing part in section with a plastic coating; FIG. 6 shows a housing part in section with an intermediate layer between the base part and the bearing holder; FIG. 7 shows a housing part in which the bearing holder forms rolling surfaces for rolling bodies; FIG. 8 shows a housing part with lubricant channels, and FIG. 9 shows an exemplary vehicle having an electric machine of the proposed type.DETAILED DESCRIPTION OF THE INVENTIONIt is stated by way of introduction that identical parts in the different embodiments are provided with the same reference numerals or component names, optionally with different indices. The disclosure of a component contained in the description can be transferred analogously to another component with the same reference sign or the same component designation. The position information selected in the description, such as for example "top", "bottom", "rear", "front", "lateral" and so forth, also relate to the directly described and illustrated figure and, in the event of a position change, are to be transferred analogously to the new position.FIG. 1 shows a sectional view of a schematically illustrated electric geared motor 1, which comprises an electric motor 2 and a transmission 3 coupled thereto. For this purpose, the electric geared motor 1 comprises a geared motor housing 4 with a motor housing 5, which is associated with the electric motor 2, and a gear mechanism base housing 6 with a bearing shield 7, wherein the bearing shield 7 is associated with the gear mechanism 3 and the gear mechanism base housing 6 is associated with both the electric motor 2 and the gear mechanism 3. The bearing shield 7, which is generally understood as a housing part and can be designated as such, comprises a base part 8 and a bearing holder 9 arranged in a recess or depression B of the base part 8, which will be explained in detail below.In addition, the electric geared motor 1 comprises a plurality of rolling bearings 10 and, in the region of the electric motor 1, a rotor 11 which is fastened to a rotor shaft 12 and is mounted rotatably about a rotor axis A, and a stator 13 arranged in the motor housing 5. On the transmission shaft 16 is also mounted a further pinion 17 which is in mesh with a further gearwheel 18 which is mounted on a transmission shaft (output shaft) 19.It is pointed out that the design of the electric geared motor 1 is purely exemplary and this can also be designed differently.FIGS. 2 and 3 show a first example of a housing part 7 a, now in an oblique view, wherein FIG. 2 shows an exploded view of the housing part 7 aand FIG. 2 shows the housing part 7 ain the assembled state.The housing part 7a for a transmission 3 comprises a base part 8a which comprises a recess or depression B and a one-piece bearing holder 9a arranged in the recess or depression B. Generally, the bearing holder 9a serves for mounting a plurality of gear shafts 16, 19 of the gear mechanism 3. In a case b), the bearing holder 9 aforms a plurality of bearing shells, which each serve as a rolling surface for rolling bodies of a respective rolling bearing 10 for a respective transmission shaft 16, 19 of the transmission 3 (see also FIG. 7 in this respect).The transmission 3 thus comprises a housing with a housing part 7, 7 a, a plurality of roller bearings 10 which are accommodated in the bearing holder 9, 9 aand a plurality of transmission shafts 16, 19 rotatably mounted in the roller bearings 10 with gearwheels 14, 15, 17, 18 arranged thereon. In one embodiment, a bearing holder 9, 9a is provided only at one end of the transmission shafts 16, 19, as in Fig. 1. However, it is advantageous if one bearing holder 9, 9a is provided at one end of each of the transmission shafts 16, 19. Accordingly, a further housing part 7, 7 awith base part 8, 8 aand bearing holders 9, 9 ain FIG. 1 could additionally also be provided on the left side of the transmission shafts 16, 19. It would of course also be possible for a housing part 7, 7 awith a base part 8, 8 aand bearing holder 9, 9 ato be provided only on the motor side.A method for producing a housing part 7 afor a transmission 3 can comprise, in particular, the following steps:providing a base part 8, 8a which comprises a recess or depression B, andarranging a one-piece bearing holder 9, 9a in the recess or depression B of the base part 8, 8a, wherein a) a plurality of rolling bearings 10 for gear shafts 16, 19 of the gear 3 are accommodated in the bearing holder 9, 9a, or b) the bearing holder 9, 9a forms a plurality of bearing shells, which each serve as a rolling surface for rolling bodies of a respective rolling bearing 10 for a respective gear shaft 16, 19 of the gear 3.The rolling bearings 10 arranged in a bearing holder 9, 9 acan be arranged in a single plane, but they can also be offset axially with respect to one another. In particular, in case a) at least three rolling bearings 10 can be provided in the bearing holder 9 or in case b) bearing shells of at least three rolling bearings 10, as is the case in the example shown in FIGS. 2 and 3.For example, the base part 8, 8 acan be manufactured from a first material and the bearing holder 9, 9 acan be manufactured from a second material, wherein the strength of the second material is above the strength of the first material. The first material and / or the second material can be a metal in particular. The first material and / or the second material can, however, also be a plastic. The materials can be combined as desired, so that the following combinations are conceivable for the first material and second material: metal / metal, metal / plastic, plastic / metal, plastic / plastic. Suitable plastics for the base part 8, 8 aand the bearing holder 9, 9 aare in particular fiber-reinforced plastics. As fibers, for example, glass fibers, aramid fibers, Kevlar fibers or carbon fibers can be used. The fibers can be processed, for example, in the form of woven fabrics, knitted fabrics, braids or fiber mats.In particular, the first material (of the base part 8, 8 a) can be an aluminum alloy and the second material (of the bearing holder 9, 9 a) can be steel. Stainless steel can be provided in particular as the steel, but the use of a stainless steel is also conceivable. Because the gear shafts 16, 19 and the gears 14, 15, 17, 18 seated thereon are usually likewise made of steel, the same coefficient of thermal expansion results for the bearing holder 9, 9 a, the gear shafts 16, 19 and the gears 14, 15, 17, 18, whereby the axial distance and the diameter of the pitch circles likewise remain constant, specifically independently of the selection of the first material. A hot forming plate can be provided in particular for the second material. Furthermore, the bearing holder 9, 9 acan be designed as a stamped part or stamped and bent part.In general, the forces acting on the transmission shafts 16, 19 cause deformations of the housing 4, in which the bearings 10 for the transmission shafts 16, 19 are arranged. Specifically, in the example shown in FIG. 1, this relates to the gear base housing 6 and the housing part or bearing plate 7.The proposed measures make it possible to provide different part properties, in particular different material properties, for the base part 8, 8 aand the bearing holder 9, 9 a, which are specifically aligned with the respective requirements. For example, the base part 8, 8 acan be soft in comparison to the bearing holder 9, 9 a. For example, ribbing otherwise necessary for a transmission housing can be made more tender or even omitted, since forces acting relatively between the transmission shafts 16, 19 and impressed into the rolling bearings 10 are absorbed by the bearing holder 9, 9a itself.The bearing holder 9, 9 acan be embedded in the recess or depression B of the base part 8, 8 ain a releasable or non-releasable manner. If it is detachably embedded, the bearing holder 9, 9a can easily be replaced if necessary, for example if it is broken. However, advantages also result if a transmission 3 is reconstructed only slightly enough that the base part 8, 8 acan be used further. Adaptation to the modified construction can then be effected by simple replacement of the bearing holder 9, 9a. If the bearing holder 9, 9a is embedded in the recess or depression B of the base part 8, 8a in a non-detachable manner, the housing part 7, 7a is particularly stable and can be held for a long time. In particular, the bearing holder 9, 9 acan be pressed, cast or glued into the base part 8, 8 a.FIG. 4 now shows a further example of a housing part 7 bin section. The housing part 7b again has a base part 8b and a bearing holder 9b arranged therein and is constructed in a similar manner to the housing parts 7, 7a already illustrated in FIGS. 1 to 3. Specifically, a material thickness a of the base part 8 bat a distance b of 0 to 40 mm from the bearing holder 9 bis advantageously not more than 20% above a material thickness a of the base part 8 bat a distance b of >40 mm from the bearing holder 9 b. In other words, the base part 8 bhas no or no substantial thickening in the region of the bearing holder 9 b. As a result, the risk for voids can be avoided or at least significantly reduced if the base part 8 bis designed as a cast part. In particular, the proposed measures can be applied if the strength of the bearing holder 9 bis above the strength of the base part 8 b. Further preferred distance ranges instead of 0 to 40 mm / >40 mm are 0 to 30 mm / >30 mm and 0 to 20 mm / >20 mm.FIG. 5 shows a further housing part 7c which is similar to the housing part 7b shown in FIG. 4. In contrast to this, the bearing holder 9 cin this example is coated with a plastic on a surface not covered by the base part 8 b. That is, the bearing holder 9 cin this example has a coating 20 facing the interior of the transmission 3. As a result, the bearing holder 9 cmay be well protected from corrosion, for example. In particular, the strength of the second material (of the bearing holder 9 c) can be above the strength of the plastic of the coating 20. In particular, the modulus of elasticity of the second material (of the bearing holder 9 c) can be above the modulus of elasticity of the plastic of the coating 20. It is also conceivable for the bearing holder 9 cto be coated on all sides with a plastic.FIG. 6 shows a further housing part 7 dwhich is similar to the housing part 7 billustrated in FIG. 4. In contrast to this, an intermediate layer 21 made of a plastic is provided between the base part 8 dand the bearing holder 9 d.Preferably, the intermediate layer 21 satisfies the condition in a temperature range of -50° to 200° CHere, α 1 is the coefficient of thermal linear expansion of the first material (the base part 8d), α 2 is the coefficient of thermal linear expansion of the second material (the bearing holder 9d), and α 3 is the coefficient of thermal linear expansion of the intermediate layer 21. Moreover, the parameter d denotes the greatest expansion of the bearing holder 9d, and the parameter c denotes a thickness of the intermediate layer 21. That is, the bearing holder 9 dis not loosened even when the temperature rises. The thickness c is here significantly greater than a size difference in the case of conventional clearance fits and is in particular in a range from 0.5 mm to 2 mm.It would also be conceivable for the intermediate layer 21 to consist of a precompressed plastic and to meet the following condition in a temperature range from -50° C. to 200° C.Here, α 1 is again the coefficient of thermal linear expansion of the first material (of the base part 8 d) and α 2 is the coefficient of thermal linear expansionCoefficient of linear expansion of the second material (the bearing holder 9d). Moreover, the parameter E denotes the compressive modulus of the intermediate layer 21 and σ 20°C denotes the compressive stress at room temperature prevailing in the intermediate layer 21. In other words, the thermally caused variation of the compressive stress in the intermediate layer is not more than 10%. Yes applies to thisIn order to generate the compressive stress at room temperature necessary for holding the bearing part 9 d, it may be provided for the production method that the intermediate layer 21 is pre-compressed in accordance with the above condition during embedding of the bearing holder 9 din the recess or depression B of the base part 8 d. In this way, too, loosening of the bearing holder 9d as the temperature rises can be prevented.It is generally conceivable for the intermediate layer 21 to consist of a plastic, the damping and spring constant of which is matched to a resonant frequency of the transmission 3 or of the electric geared motor 1. As a result, the intermediate layer 21 also serves to suppress undesired noises.In a further variant of the housing part 7 d, it can be provided that the second material (of the bearing holder 9 d) is stainless steel and that an intermediate layer 21 made of rust with a thickness c of at least 50 μm is provided between the base part 8 dand the bearing holder 9 din the unused state. In this variant, rust is intentionally produced in order to ensure the anchoring of the bearing holder 9 din the base part 8 d. Specifically, the intermediate layer 21 may be made of rust after the bearing holder 9 dis embedded in the recess B of the base part 8 d. For example, the intermediate layer 21 can be produced in a targeted manner by introducing an electrolyte into a gap between the bearing holder 9 dand the base part 8 dand / or by applying an electrical voltage between the bearing holder 9 dand the base part 8 d.FIG. 7 shows a further housing part 7 ewhich is similar to the housing part 7 billustrated in FIG. 4. Specifically, the case b) is shown in which the bearing holder 9 eforms a plurality of bearing shells C, which each serve as a rolling surface for rolling bodies 22 of a respective rolling bearing 10 for a respective transmission shaft 16, 19 of the transmission 3. Accordingly, the "outer rings" of the rolling bearings 10 are included in the bearing holder 9 e. The inner rings 23, on the other hand, roll off in a known manner on the rolling bodies 22.FIG. 8 shows a further housing part 7 fwhich is similar to the housing part 7 billustrated in FIG. 4. In contrast thereto, the housing part 7 fhas lubricant channels 24 for at least one of the rolling bearings 10. In this way, the rolling bearings 10 can be supplied with a lubricant during operation of the transmission. Specifically, a lubricant passage 24 may be provided at the following positions:(directly) between the bearing holder 9f and the base part 8f,between the bearing holder 9 fand a plastic coating 20 or between the base part 8 fand a plastic coating 20 (see also FIG. 5 ),between the bearing holder 9 fand an intermediate layer 21 or between the base part 8 fand an intermediate layer 21 (see also FIG. 6 ).For example, the lubricant channel 24 can be produced during the casting of the base part 8 fof the bearing holder 9 for during the injection molding of the plastic coating 20 or of the intermediate layer 21, in particular using a lost core. In particular, lubricant channels 24 can be provided for all rolling bearings 10 arranged in bearing holder 9 f.It is also noted at this point that the variants presented, in particular the variants shown in FIGS. 1 to 8, can be combined in any desired manner. For example, an intermediate layer 21 can accommodate a lubricant channel 24 and simultaneously meet the condition. It is also conceivable that an intermediate layer 21 made of rust with a thickness c of at least 50 μm is provided between the base part 8 eand the bearing holder 9 eof FIG. 8 in the unused state, and so on.FIG. 9 finally shows the electric geared motor 1 installed in a vehicle 25. Specifically, the electric geared motor 1 is connected to the half axles 26 of the rear axle. Finally, the driven wheels 27 are mounted on the half axles 26. The vehicle 25 is driven at least partially or temporarily by the electric geared motor 1. that is, the electric geared motor 1 can serve for driving the vehicle 25 alone or can be provided in combination with an internal combustion engine (hybrid drive), for example.Finally, it is to be noted that the scope of protection is defined by the claims. However, the specification and drawings are to be used to interpret the claims. The features contained in the figures can be interchanged and combined with one another as desired. In particular, it is also noted that the devices shown can also comprise more or fewer components than those shown in reality. In some cases, the devices shown or their components can also be shown in an unscaled and / or enlarged and / or reduced form.List of reference characters1 Electric geared motor 2 Electric motor 3 Gear 4 Geared motor housing 5 Motor housing 6 Gear base housing 7, 7 a..7 f Gehäuseteil part (bearing plate) 8, 8 a..8 fBase part 9, 9 a..9 f Lager holder 10 Rolling bearing 11 Rotor 12 Rotor shaft 13 Stator 14 Pinion 15 Gearwheel 16 Gear shaft / intermediate shaft 17 Pinion 18 Gearwheel 19 Gear shaft / output shaft 20 Coating 21 Intermediate layer 22 Rolling bodies 23 Inner ring 24 Lubricant channel 25 Vehicle 26 Semi-axis 27 Wheel A Rotor axis B Recess / depression C Bearing shell a Material thickness Base part b Distance of bearing holder c Thickness Intermediate layer d Extension of bearing holder

Claims

Housing part (7, 7a..7f) for a transmission (3), comprising a base part (8, 8a..8f) which comprises a recess or depression (B), characterized by - a one-piece bearing holder (9, 9a..9f), a) which is arranged in the recess or depression (B) and in which a plurality of rolling bearings (10) for transmission shafts (17, 19) of the transmission (3) are accommodated, or b) which forms a plurality of bearing shells (C) which each serve as a rolling surface for rolling bodies (22) of in each case one rolling bearing (10) for in each case one transmission shaft (17, 19) of the transmission (3).Housing part (7, 7a..7f) according to claim 1, characterised in that the base part (8, 8a..8f) is made of a first material and the bearing holder (9, 9a..9f) is made of a second material, wherein the strength of the second material is above the strength of the first material.Housing part (7, 7a..7f) according to claim 2, characterised in that the first material is an aluminium alloy and the second material is steel.Housing part (7, 7a..7f) according to one of Claims 1 to 3, characterized in that a material thickness (a) of the base part (8, 8a..8f) at a distance (b) of 0 to 40 mm from the bearing holder (9, 9a..9f) is not more than 20% above a material thickness (a) of the base part (8, 8a..8f) at a distance (b) of >40 mm from the bearing holder (9, 9a..9f).Housing part (7, 7a..7f) according to one of Claims 1 to 4, characterized in that the bearing holder (9, 9a..9f) is coated with a plastic on all sides or only on a surface not covered by the base part (8, 8a..8f).Housing part (7, 7a..7f) according to one of Claims 2 to 5, characterized in that an intermediate layer (21) made of a plastic is provided between the base part (8, 8a..8f) and the bearing holder (9, 9a..9f), wherein the intermediate layer (21) satisfies the condition c ≥ α 1 - α 2 2 ⋅ α 3 ⋅ d in a temperature range from -50° to 200°C, wherein α 1 is the coefficient of thermal linear expansion of the first material, α 2 is the coefficient of thermal linear expansion of the second material and α 3 is the coefficient of thermal linear expansion of the intermediate layer (21), wherein (d) is the greatest expansion of the bearing holder (9, 9a..9f), and wherein (c) is a thickness of the intermediate layer (21).Housing part (7, 7a..7f) according to one of Claims 2 to 5, characterized in that an intermediate layer (21) made of a precompressed plastic is provided between the base part (8, 8a..8f) and the bearing holder (9, 9a..9f), wherein the intermediate layer (21) satisfies the condition E ≤ 0.1 ⋅ σ 20° C α 1 - α 2 in a temperature range from -50° to 200°C, wherein α 1 is the coefficient of thermal linear expansion of the first material and α 2 is the coefficient of thermal linear expansion of the second material, wherein E is the modulus of compressive elasticity of the intermediate layer (21) and wherein σ 20°C is the compressive stress prevailing in the intermediate layer (21) at room temperature.Housing part (7, 7a..7f) according to one of claims 2 to 5, characterised in that the second material is stainless steel and in that between the base part (8, 8a..8f) and the bearing holder (9, 9a..9f) in the unused state an intermediate layer (21) of stainless steel with a thickness (c) of at least 50 μm is provided.Housing part (7, 7a..7f) according to one of Claims 1 to 8, characterized in that the bearing holder (9, 9a..9f) is embedded in the recess or depression (B) of the base part (8, 8a..8f) in a releasable or non-releasable manner.Housing part (7, 7a..7f) according to one of Claims 1 to 9, characterized in that a lubricant channel (24) for at least one of the rolling bearings (10) is provided between the bearing holder (9, 9a..9f) and the base part (8, 8a..8f), between the bearing holder (9, 9a..9f) and a plastics coating (20) produced according to Claim 5, between the bearing holder (9, 9a..9f) and an intermediate layer (21) according to one of Claims 6 to 8, between the base part (8, 8a..8f) and a plastics coating (20) produced according to Claim 5, or between the base part (8, 8a..8f) and an intermediate layer (21) according to one of Claims 6 to 8.Transmission (3) comprising a housing with a housing part (7, 7a..7f) according to one of claims 1 to 10, a plurality of rolling bearings (10) which are accommodated in the bearing holder (9, 9a..9f) and a plurality of transmission shafts (16, 19) rotatably mounted in the rolling bearings (10) and having gearwheels (14, 15, 17, 18) arranged thereon.Transmission (3) according to Claim 11, characterized in that an intermediate layer (21) made of a plastic is provided between the base part (8, 8a..8f) and the bearing holder (9, 9a..9f), the damping and spring constant of which intermediate layer is matched to a resonant frequency of the transmission (3).Electric geared motor (1) comprising an electric motor (2) and a transmission (3) according to claim 12 coupled thereto.Vehicle (25) with an electric geared motor (1) according to claim 13, provided for driving the vehicle (25).Method for producing a housing part (7, 7a..7f) for a transmission (3), comprising the steps of - providing a base part (8, 8a..8f) which comprises a recess or depression (B) and - arranging a one-piece bearing holder (9, 9a..9f) in the recess or depression (B) of the base part (8, 8a..8f), wherein a) a plurality of rolling bearings (10) for transmission shafts (17, 19) of the transmission (3) are accommodated in the bearing holder (9, 9a..9f) or b) the bearing holder (9, 9a..9f) forms a plurality of bearing shells (C) which each serve as a rolling surface for rolling bodies (22) of in each case one rolling bearing (10) for in each case one transmission shaft (17, 19) of the transmission (3).

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