Housing part for a transmission with improved mounting of transmission 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). Furthermore, the housing part (7, 7a.7f) comprises a single-part bearing holder (9, 9a.9f) which is arranged in the recess or depression (B). In a case a), a plurality of anti-friction bearings (10) for transmission shafts (17, 19) of the transmission (3) are received in the bearing holder (9, 9a.9f). In a case 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 anti-friction bearing (10) for in each case one transmission shaft (17, 19) of the transmission (3). Furthermore, a transmission (3) with a housing part (7, 7a.7f) of this type is specified, which has a plurality of anti-friction bearings (10) received in the bearing holder (9, 9a.9f) and a plurality of transmission shafts (16, 19) mounted rotatably in the anti-friction bearings (10) with gearwheels (14, 15, 17, 18) arranged thereon. In addition, an electric geared motor (1) with a transmission (3) of this type, a vehicle (25) with an electric geared motor (1) of this type, and a method for producing a housing part (7, 7a.7f) of this type are specified.

Description

[0001] Housing part for a gearbox with improved bearings for gear shafts

[0002] TECHNICAL FIELD

[0003] The invention relates to a housing part for a transmission, which comprises a base part having a recess or depression. Furthermore, the invention relates to a transmission comprising a housing with such a housing part, a plurality of rolling bearings, and a plurality of gear shafts rotatably mounted in the rolling bearings with gears arranged thereon. Furthermore, the invention relates to an electric geared motor with an electric motor and a transmission of the type mentioned above coupled thereto, as well as to a vehicle with 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 type mentioned.

[0004] STATE OF THE ART

[0005] Such a housing part, such a transmission, such an electric machine, such a vehicle, and such a manufacturing process are generally known from the prior art. The problem is that the forces acting on the shafts cause deformation of the housing in which the bearings for the shafts are located. These deformations can lead to variations in the distance and position of the shafts relative to one another, thus resulting in suboptimal transmission function and increased noise emissions.

[0006] DISCLOSURE OF THE INVENTION

[0007] An object of the invention is therefore to provide an improved transmission housing part, an improved transmission, an improved electric machine, an improved vehicle with an electric machine, and an improved manufacturing method for a transmission housing part. In particular, optimal transmission function with low noise emissions is to be achieved.

[0008] The object of the invention is achieved with a housing part of the type mentioned at the outset, which comprises a one-piece bearing holder arranged in the recess or depression, a) in which several rolling bearings for gear shafts of the transmission are accommodated, or b) which forms several bearing shells, each of which serves as a rolling surface for rolling elements of a rolling bearing for a gear shaft of the transmission.

[0009] Furthermore, the object of the invention is achieved with a gear comprising a housing with a housing part of the above-mentioned type, as well as several rolling bearings which are accommodated in the bearing holder and several gear shafts rotatably mounted in the rolling bearings with gear wheels arranged thereon.

[0010] Furthermore, the object of the invention is achieved with an electric gear motor which comprises an electric motor and a gear mechanism of the above-mentioned type coupled thereto.

[0011] In addition, the object of the invention is achieved with a vehicle having such an electric machine which is intended to drive the vehicle.

[0012] Finally, the object of the invention is achieved by a method for producing a housing part for a transmission, which comprises the following steps:

[0013] Providing a base part which comprises a recess or depression and

[0014] Arranging a one-piece bearing holder in the recess or depression of the base part, wherein a) several rolling bearings for gear shafts of the gearbox are accommodated in the bearing holder or b) the bearing holder forms several bearing shells, each of which serves as a rolling surface for rolling elements of one rolling bearing each for one gear shaft of the gearbox.

[0015] The proposed measures allow different properties, particularly different material properties, to be provided for the base part and the bearing retainer, specifically tailored to the respective requirements. For example, the base part can be designed to be softer than the bearing retainer. For example, ribbing otherwise required for a gearbox housing can be made more delicate or even eliminated altogether, since the relative forces acting between the gearbox shafts and impressed on the rolling bearings are absorbed by the bearing retainer itself.

[0016] In particular, in case a) at least three rolling bearings or in case b) bearing shells of at least three rolling bearings can be provided in the bearing holder.

[0017] The gear unit can be designed, for example, as a spur gear unit, in particular as a helical gear unit. In one embodiment, a bearing holder is provided only at one end of the gear shafts. However, it is advantageous if a bearing holder is provided at each end of the gear shafts. The bearings arranged in a bearing holder can be arranged in a single plane, but they can also be axially offset from one another.

[0018] Further advantageous embodiments and developments of the invention emerge from the subclaims and from the description in conjunction with the figures.

[0019] It is advantageous if the base part is made of a first material and the bearing holder is made of a second material, the strength of the second material being greater than the strength of the first material. The first material and / or the second material can in particular be a metal. However, the first material and / or the second material can also be a plastic. The materials can be combined as desired, so that the following combinations for the first material and second material are conceivable: metal / metal, metal / plastic, plastic / metal, plastic / plastic. Fiber-reinforced plastics are particularly suitable as plastics for the base part and the bearing holder. Examples of fibers that can be used include glass fibers, aramid fibers, Kevlar fibers or carbon fibers. The fibers can be processed, for example, in the form of woven fabrics, knitted fabrics, braids or fiber mats.

[0020] It is advantageous if the first material is an aluminum alloy and the second material is steel. Stainless steel can be used as the steel, but the use of rusting steel is also conceivable. Because the gear shafts and the gears mounted on them are usually also made of steel, the bearing holder, the gear shafts, and the gears have the same coefficient of thermal expansion, whereby the center distance and the diameter of the pitch circles also remain constant, regardless of the choice of the first material. A hot-formed sheet can be used for the second material. Furthermore, the bearing holder can be designed as a stamped part or a stamped and bent part.

[0021] It is also advantageous if the material thickness of the base part at a distance of 0 to 40 mm from the bearing holder is no more than 20% higher than the material thickness of the base part at a distance of >40 mm from the bearing holder. According to the state of the art, gearbox housings in which rolling bearings are embedded have increased material thicknesses in the area of ​​these bearings in order to securely hold the rolling bearings and to be able to absorb the forces that occur during gearbox operation. However, this also increases the risk of shrinkage cavities if the gearbox housing is cast. By providing a bearing holder, the material thickness of the base part does not need to be significantly increased, even in the immediate vicinity of the bearing holder, which avoids or at least significantly reduces the risk of shrinkage cavities. In particular, the proposed measures can be applied if the strength of the bearing holder exceeds that of the base part.Other 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.

[0022] It is advantageous if the bearing holder is coated with a plastic on all sides or only on an area not covered by the base part. This provides the bearing holder with good protection against corrosion, for example. In particular, the strength of the second material can be higher than the strength of the plastic in the coating. In particular, the elastic modulus of the second material can be higher than the elastic modulus of the plastic in the coating.

[0023] 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 meets the condition in a temperature range of -50° to 200°C, where ai is the thermal expansion coefficient of the first material, 0C2 is the thermal expansion coefficient of the second material and co is the thermal expansion coefficient of the intermediate layer, where d is the greatest expansion of the bearing holder and where 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. This means that the bearing holder does not loosen even when the temperature rises. The thickness c is significantly greater than a size difference in usual clearance fits and is in particular in a range of 0.5 mm to 2 mm.

[0024] 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, the intermediate layer fulfilling the condition £■ <

[0025] ~ 900 in a temperature range of -50° to 200°C, where ai is the thermal expansion coefficient of the first material and 0C2 is the thermal expansion coefficient of the second material, where E is the compressive modulus of elasticity of the intermediate layer, where G2O°C is the compressive stress prevailing in the intermediate layer at room temperature, where d is the largest extension of the bearing holder (9, 9a..9f) and c is a thickness of the intermediate layer. In other words, the thermally induced variation of the compressive stress in the intermediate layer is not more than 10%.

[0026] To generate the compressive stress necessary to hold the bearing part at room temperature, the manufacturing process can include pre-compressing the intermediate layer according to the above condition when embedding the bearing retainer in the recess or depression of the base part. This also prevents the bearing retainer from loosening as the temperature rises.

[0027] It is also particularly advantageous if the second material is rusting 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 unused condition. In this variant, rust is deliberately created to ensure the anchoring of the bearing holder in the base part. Specifically, the intermediate layer of rust can be produced after the bearing holder has been embedded in the recess or depression of the base part. For example, the intermediate layer can be deliberately created by introducing an electrolyte into a gap between the bearing holder and base part and / or by applying an electrical voltage between the bearing holder and base part. In one design variant of the housing part, the bearing holder is detachably embedded in the recess or depression of the base part. This means that the bearing holder can be easily replaced if necessary, for example if it is broken.However, advantages also arise when a gearbox is redesigned only slightly so that the base part can be reused. Adaptation to the modified design can then be achieved by simply replacing the bearing retainer. In this context, the term "removable" specifically means that the bearing retainer can be separated from the base part without causing damage, without heating the housing above a temperature of 200°C. In other words, this means that a bearing retainer that has been removed from the base part can be reinserted into the recess or depression of the base part without any further measures.

[0028] In another design variant of the housing part, the bearing retainer is permanently embedded in the recess or depression of the base part. In this context, the term "permanently" means in particular that the bearing retainer cannot be separated from the base part without causing damage without heating the housing to a temperature above 200°C. In other words, this means that a bearing retainer that has been removed from the base part cannot be permanently and permanently embedded back into the recess or depression of the base part without further measures. In particular, the bearing retainer can be pressed, cast, or glued into the base part.

[0029] 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 type mentioned above, between the bearing holder and an intermediate layer of the type mentioned above, between the base part and a plastic coating of the type mentioned above, or between the base part and an intermediate layer of the type mentioned above. 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.

[0030] Finally, it is particularly advantageous to provide an intermediate layer made of a plastic between the base part and the bearing holder, whose damping and spring constant are tuned to a resonant frequency of the gearbox or the electric gear motor. This also serves to suppress unwanted noise.

[0031] SHORT DESCRIPTION OF THE CHARACTERS

[0032] Embodiments of the invention are illustrated by way of example in the accompanying schematic figures. They show:

[0033] Fig. 1 shows a half section through an exemplary electric gear motor;

[0034] Fig. 2 is an exploded view of a housing part with bearing holder;

[0035] Fig. 3 shows the housing part from Fig. 2 in assembled state;

[0036] Fig. 4 a housing part in section with approximately constant material thickness;

[0037] Fig. 5 shows a housing part in section with a plastic coating;

[0038] Fig. 6 a housing part in section with an intermediate layer between base part and bearing holder;

[0039] Fig. 7 shows a housing part in which the bearing holder forms rolling surfaces for rolling elements; Fig. 8 shows a housing part with lubricant channels and

[0040] Fig. 9 shows an exemplary vehicle with an electric machine of the proposed type.

[0041] DETAILED DESCRIPTION OF THE INVENTION

[0042] By way of introduction, it should be noted that identical parts in the different embodiments are provided with the same reference symbols or component designations, possibly with different indices. The disclosure of a component contained in the description can be applied mutatis mutandis to another component with the same reference symbol or component designation. Furthermore, the positional information chosen in the description, such as "top," "bottom," "rear," "front," "side," and so on, refers to the directly described and illustrated figure and, in the event of a change in position, is to be applied mutatis mutandis to the new position.

[0043] Fig. 1 shows a sectional view of a schematically illustrated electric geared motor 1, which comprises an electric motor 2 and a gearbox 3 coupled thereto. For this purpose, the electric geared motor 1 comprises a geared motor housing 4 with a motor housing 5, which is assigned to the electric motor 2, and a gearbox base housing 6 with a bearing plate 7, wherein the bearing plate 7 is assigned to the gearbox 3 and the gearbox base housing 6 is assigned to both the electric motor 2 and the gearbox 3. The bearing plate 7, which can generally be understood as a housing part and named as such, comprises a base part 8 and a bearing holder 9 arranged in a recess or depression B in the base part 8, which will be explained in more detail below.

[0044] In addition, the electric geared motor 1 comprises a plurality of rolling bearings 10 and, in the area of ​​the electric motor 1, a rotor 11 which is fastened to a rotor shaft 12 and mounted for rotation about a rotor axis A, and a stator 13 arranged in the motor housing 5. In the area of ​​the gearbox 3, the electric geared motor 1 further comprises a pinion 14 mounted on the rotor shaft 12, which engages with a gear 15 mounted on a gearbox shaft (intermediate shaft) 16. Also mounted on the gearbox shaft 16 is a further pinion 17, which engages with a further gear 18 mounted on a gearbox shaft (output shaft) 19.

[0045] It is pointed out that the design of the electric gear motor 1 is purely exemplary and can also be designed differently.

[0046] Fig. 2 and 3 show a first example of a housing part 7a, now in an oblique view, wherein Fig. 2 shows an exploded view of the housing part 7a and Fig. 2 shows the housing part 7a in the assembled state.

[0047] The housing part 7a for a gearbox 3 comprises a base part 8a, which includes a recess or depression B, and a one-piece bearing holder 9a arranged in the recess or depression B. In general, the bearing holder 9a serves to support several gearbox shafts 16, 19 of the gearbox 3. In case a), several rolling bearings 10 for the gearbox shafts 16, 19 of the gearbox 3 are accommodated in the bearing holder 9a. In case b), the bearing holder 9a forms several bearing shells, each of which serves as a rolling surface for rolling elements of a respective rolling bearing 10 for a respective gearbox shaft 16, 19 of the gearbox 3 (see also Fig. 7).

[0048] The gear unit 3 thus comprises a housing with a housing part 7, 7a, a plurality of rolling bearings 10 which are accommodated in the bearing holder 9, 9a, and a plurality of gear shafts 16, 19 rotatably mounted in the rolling bearings 10 with gears 14, 15, 17, 18 arranged thereon. The gear unit 3 can be designed, for example, as a spur gear unit, in particular as a helical spur gear unit. In one embodiment, a bearing holder 9, 9a is provided only at one end of the gear shafts 16, 19, as is the case in Fig. 1. However, it is advantageous if a bearing holder 9, 9a is provided at each end of the gear shafts 16, 19. Accordingly, a further housing part 7, 7a with base part 8, 8a and bearing holder 9, 9a could also be provided in Fig. 1 on the left side of the transmission shafts 16, 19. Of course, it would also be possible for a housing part 7, 7a with base part 8, 8a and bearing holder 9, 9a to be provided only on the motor side.

[0049] A method for producing a housing part 7a for a transmission 3 may in particular comprise the following steps:

[0050] Providing a base part 8, 8a, which comprises a recess or depression B and

[0051] Arranging a one-piece bearing holder 9, 9a in the recess or depression B of the base part 8, 8a, wherein a) several 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 several bearing shells, each of which serves as a rolling surface for rolling elements of a respective rolling bearing 10 for a respective gear shaft 16, 19 of the gear 3.

[0052] The rolling bearings 10 arranged in a bearing holder 9, 9a can be arranged in a single plane, but they can also be axially offset from 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 can be provided, as is the case in the example shown in Figs. 2 and 3.

[0053] For example, the base part 8, 8a can be made from a first material and the bearing holder 9, 9a from a second material, wherein the strength of the second material is greater than the strength of the first material. The first material and / or the second material can in particular be a metal. However, the first material and / or the second material can also be a plastic. The materials can be combined as desired, so that the following combinations for the first material and second material are conceivable: metal / metal, metal / plastic, plastic / metal, plastic / plastic. Fiber-reinforced plastics are particularly suitable as plastics for the base part 8, 8a and the bearing holder 9, 9a. Fibers that can be used, for example, are glass fibers, aramid fibers, Kevlar fibers or carbon fibers. The fibers can be processed, for example, in the form of woven fabrics, knitted fabrics, braids or fiber mats.

[0054] In particular, the first material (of the base part 8, 8a) can be an aluminum alloy and the second material (of the bearing holder 9, 9a) can be steel. Stainless steel, in particular, can be provided as the steel, but the use of rusting steel is also conceivable. Because the gear shafts 16, 19 and the gears 14, 15, 17, 18 mounted thereon are usually also made of steel, the bearing holder 9, 9a, the gear shafts 16, 19, and the gears 14, 15, 17, 18 have the same thermal expansion coefficient, whereby the center distance and the diameter of the pitch circles also remain constant, regardless of the choice of the first material. A hot-formed sheet can be provided for the second material. Furthermore, the bearing holder 9, 9a can be designed as a stamped part or a stamped-bent part.

[0055] In general, the forces acting on the gear shafts 16, 19 cause deformation of the housing 4, in which the bearings 10 for the gear shafts 16, 19 are arranged. Specifically, in the example shown in Fig. 1, this affects the gear base housing 6 as well as the housing part or bearing plate 7. The deformations can lead to variations in the distance and position of the gear shafts 16, 19 relative to one another and thus to suboptimal function of the gear 3 and increased noise emissions.

[0056] The proposed measures allow different part properties, particularly different material properties, to be provided for the base part 8, 8a and the bearing holder 9, 9a, which are specifically tailored to the respective requirements. For example, the base part 8, 8a can be designed to be softer than the bearing holder 9, 9a. For example, ribbing otherwise required for a gearbox housing can be made more delicate or even eliminated altogether, since forces acting relatively between the gearbox shafts 16, 19 and impressed on the rolling bearings 10 are absorbed by the bearing holder 9, 9a itself.

[0057] The bearing holder 9, 9a can be removably or permanently embedded in the recess or depression B of the base part 8, 8a. If it is removably embedded, the bearing holder 9, 9a can be easily replaced if necessary, for example if it is broken. Advantages also arise if a gearbox 3 is only slightly redesigned so that the base part 8, 8a can continue to be used. Adaptation to the changed design can then be achieved by simply replacing the bearing holder 9, 9a. If the bearing holder 9, 9a is permanently embedded in the recess or depression B of the base part 8, 8a, the housing part 7, 7a is particularly stable and durable. In particular, the bearing holder 9, 9a can be pressed, cast, or glued into the base part 8, 8a.

[0058] Fig. 4 now shows a further example of a housing part 7b in section. The housing part 7b again has a base part 8b and a bearing holder 9b arranged therein and is constructed similarly to the housing parts 7, 7a already shown in Figs. 1 to 3. Specifically, a material thickness a of the base part 8b at a distance b of 0 to 40 mm from the bearing holder 9b is advantageously no more than 20% greater than a material thickness a of the base part 8b at a distance b of >40 mm from the bearing holder 9b. In other words, the base part 8b has no or no significant thickening in the area of ​​the bearing holder 9b. As a result, the risk of shrinkage cavities can be avoided or at least significantly reduced if the base part 8b is designed as a cast part. In particular, the proposed measures can be applied if the strength of the bearing holder 9b is greater than the strength of the base part 8b.Other 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.

[0059] Fig. 5 shows a further housing part 7c, which is similar to the housing part 7b shown in Fig. 4. In contrast, the bearing holder 9c in this example is coated with a plastic on an area not covered by the base part 8b. This means that the bearing holder 9c in this example has a coating 20 facing the interior of the gearbox 3. This allows the bearing holder 9c to be well protected against corrosion, for example. In particular, the strength of the second material (of the bearing holder 9c) can be higher than the strength of the plastic of the coating 20. In particular, the modulus of elasticity of the second material (of the bearing holder 9c) can be higher than the modulus of elasticity of the plastic of the coating 20. It is also conceivable for the bearing holder 9c to be coated on all sides with a plastic.

[0060] Fig. 6 shows another housing part 7d, which is similar to the housing part 7b shown in Fig. 4. In contrast, an intermediate layer 21 made of a plastic is provided between the base part 8d and the bearing holder 9d.

[0061] Preferably, the intermediate layer 21 satisfies the condition in a temperature range of -50° to 200°C

[0062] Where ai is the thermal expansion coefficient of the first material (the base part 8d), 0C2 is the thermal expansion coefficient of the second material (the bearing holder 9d), and co is the thermal expansion coefficient of the intermediate layer 21. Furthermore, the parameter d denotes the greatest extension of the bearing holder 9d, and the parameter c denotes the thickness of the intermediate layer 21. In other words, the thickness c of the intermediate layer 21 is selected such that the intermediate layer 21 always connects the base part 8d and the bearing holder 9d in a temperature range from -50°C to 200°C. This means that the bearing holder 9d does not loosen even as the temperature rises.

[0063] The thickness c is significantly larger than a size difference in usual clearance fits and lies in a range of 0.5 mm to 2 mm.

[0064] It would also be conceivable that the intermediate layer 21 consists of a pre-compressed plastic and fulfills the following condition in a temperature range of -50° to 200°C.

[0065] "

[0066] E < -

[0067] 900

[0068] Here, ai is the coefficient of thermal expansion of the first material (the base part 8d) and 0C2 is the coefficient of thermal expansion of the second material (the bearing holder 9d). Furthermore, the parameter E denotes the compressive elastic modulus of the intermediate layer 21, and G20°C denotes the compressive stress prevailing in the intermediate layer 21 at room temperature, where d is the largest dimension of the bearing holder (9, 9a..9f) and c is the thickness of the intermediate layer 21. In other words, the thermally induced variation of the compressive stress in the intermediate layer does not exceed 10%.

[0069] In order to generate the compressive stress necessary to hold the bearing part 9d at room temperature, the manufacturing process can be designed to pre-compress the intermediate layer 21 according to the above condition when embedding the bearing holder 9d in the recess or depression B of the base part 8d. This also prevents the bearing holder 9d from loosening as the temperature rises.

[0070] It is generally conceivable that the intermediate layer 21 consists of a plastic whose damping and spring constant are matched to a resonant frequency of the gear 3 or the electric gear motor 1. The intermediate layer 21 thus also serves to suppress unwanted noise. In a further variant of the housing part 7d, it can be provided that the second material (of the bearing holder 9d) is rusting 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 8d and the bearing holder 9d in the unused state. In this variant, rust is intentionally created to ensure the anchoring of the bearing holder 9d in the base part 8d. Specifically, the intermediate layer 21 can be made of rust after the bearing holder 9d has been embedded in the recess or depression B of the base part 8d.For example, the intermediate layer 21 can be specifically produced by introducing an electrolyte into a gap between the bearing holder 9d and the base part 8d and / or by applying an electrical voltage between the bearing holder 9d and the base part 8d.

[0071] Fig. 7 shows another housing part 7e, which is similar to the housing part 7b shown in Fig. 4. Specifically, case b) is shown, in which the bearing holder 9e forms several bearing shells C, each of which serves as a rolling surface for rolling elements 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 enclosed by the bearing holder 9e. The inner rings 23, however, roll on the rolling elements 22 in a known manner.

[0072] Fig. 8 shows another housing part 7f, which is similar to the housing part 7b shown in Fig. 4. In contrast, the housing part 7f has 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 channel 24 can be provided at the following locations: (directly) between the bearing holder 9f and the base part 8f, between the bearing holder 9f and a plastic coating 20 or between the base part 8f and a plastic coating 20 (see also Fig. 5), between the bearing holder 9f and an intermediate layer 21 or between the base part 8f and an intermediate layer 21 (see also Fig. 6). For example, the lubricant channel 24 can be produced during the casting of the base part 8f or the bearing holder 9f or during the injection molding of the plastic coating 20 or 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 the bearing holder 9f.

[0073] At this point, it is also noted that the presented embodiments, in particular the embodiments shown in Figs. 1 to 8, can be combined in any way. 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 of rust with a thickness c of at least 50 pm is provided between the base part 8e and the bearing holder 9e of Fig. 8 in the unused state, and so on.

[0074] Finally, Fig. 9 shows the electric gear motor 1 installed in a vehicle 25. The vehicle 25 has two axles, one of which is driven. Specifically, the electric gear motor 1 is connected to the semi-axles 26 of the rear axle. Finally, the driven wheels 27 are mounted on the semi-axles 26. The vehicle 25 is driven at least partially or temporarily by the electric gear motor 1. This means that the electric gear motor 1 can serve to drive the vehicle 25 alone or, for example, be provided in conjunction with an internal combustion engine (hybrid drive).

[0075] Finally, it is noted that the scope of protection is determined by the patent claims. However, the description and drawings must 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 depicted may in reality comprise more or fewer components than shown. In some cases, the depicted devices or their components may also be shown not to scale and / or enlarged and / or reduced in size.

[0076] List of reference symbols

[0077] 1 electric gear motor

[0078] 2 Electric motor 3 Gearbox

[0079] 4 Gear motor housing

[0080] 5 Motor housing

[0081] 6 Gearbox base housing

[0082] 7, 7a..7f Housing part (bearing shield) 8, 8a..8f Base part

[0083] 9, 9a..9f warehouse keeper

[0084] 10 rolling bearings

[0085] 11 Rotor

[0086] 12 Rotor shaft 13 Stator

[0087] 14 pinions

[0088] 15 gear

[0089] 16 Gearbox shaft / intermediate shaft

[0090] 17 Pinion 18 Gear

[0091] 19 Gearbox shaft / output shaft

[0092] 20 Coating

[0093] 21 Intermediate layer

[0094] 22 Rolling elements 23 Inner ring

[0095] 24 Lubricant channel

[0096] 25 vehicles

[0097] 26 semi-axle

[0098] 27 wheels

[0099] A rotor axis

[0100] B Recess / depression

[0101] C Bearing shell a Material thickness of base part b Distance from bearing holder c Thickness of intermediate layer d Expansion of bearing holder

Claims

Patent claims 1 . Housing part (7, 7a..7f) for a gearbox (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) arranged in the recess or depression (B), a) in which a plurality of rolling bearings (10) for gearbox shafts (17, 19) of the gearbox (3) are received, or b) which forms a plurality of bearing shells (C), each of which serves as a rolling surface for rolling elements (22) of a respective rolling bearing (10) for a respective gearbox shaft (17, 19) of the gearbox (3).

2. Housing part (7, 7a..7f) according to claim 1, characterized 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, the strength of the second material being greater than the strength of the first material.

3. Housing part (7, 7a..7f) according to claim 2, characterized in that the first material is an aluminum alloy and the second material is steel.

4. 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).

5. 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).

6. 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 in a temperature range of -50° to 200°C, where ai is the thermal expansion coefficient of the first material, 0C2 is the thermal expansion coefficient of the second material and co is the thermal expansion coefficient of the intermediate layer (21), where (d) is the greatest extent of the bearing holder (9, 9a..9f) and where (c) is a thickness of the intermediate layer (21).

7. Housing part (7, 7a..7f) according to one of claims 2 to 5, characterized in that an intermediate layer (21) made of a pre-compressed 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 £■ < ~ 900 in a temperature range of -50° to 200°C, where ai is the thermal linear expansion coefficient of the first material and 0C2 is the thermal linear expansion coefficient of the second material, where E is the compressive modulus of elasticity of the intermediate layer (21), where G2O°C is the compressive stress prevailing in the intermediate layer (21) at room temperature, where (d) is the greatest extension of the bearing holder (9, 9a..9f) and (c) is a thickness of the intermediate layer (21).

8. Housing part (7, 7a..7f) according to one of claims 2 to 5, characterized in that the second material is stainless steel and that between the base part (8, 8a..8f) and the bearing holder (9, 9a..9f) in the unused state a An intermediate layer (21) of rust having a thickness (c) of at least 50 gm is provided.

9. Housing part (7, 7a..7f) according to one of claims 1 to 8, characterized in that the bearing holder (9, 9a..9f) is releasably or non-releasably embedded in the recess or depression (B) of the base part (8, 8a..8f).

10. 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 plastic 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 plastic 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.

11. Gearbox (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 gear shafts (16, 19) rotatably mounted in the rolling bearings (10) with gear wheels (14, 15, 17, 18) arranged thereon.

12. Gearbox (3) according to claim 1 1, characterized in that between the base part (8, 8a..8f) and the bearing holder (9, 9a..9f) there is provided an intermediate layer (21) made of a plastic, the damping and spring constant of which is matched to a resonance frequency of the gearbox (3).

13. Electric geared motor (1), comprising an electric motor (2) and a gear (3) coupled thereto according to claim 12.

14. Vehicle (25) with an electric gear motor (1) according to claim 13, which is provided for driving the vehicle (25).

15. Method for producing a housing part (7, 7a..7f) for a transmission (3), comprising the steps 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) several rolling bearings (10) for gear shafts (17, 19) of the gear (3) are accommodated in the bearing holder (9, 9a..9f) or b) the bearing holder (9, 9a..9f) forms several bearing shells (C), which each serve as a rolling surface for rolling elements (22) of a respective rolling bearing (10) for a respective gear shaft (17, 19) of the gear (3).

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