Bearing end cap for electric motor, electric motor and manufacturing method

Abstract

The invention relates to a bearing end cap for an electric motor, in particular for or in an electric power steering system, comprising: a bearing section which is designed to support a motor shaft; and a sealing section which is designed for a sealing connection with respect to the motor housing, the sealing section having a circumferential sealing groove which is axially oriented with respect to the bearing section, the sealing groove being designed for receiving a circumferential seal and for receiving an axial edge section of the motor housing in order to press the seal. The invention also relates to an electric motor for an electric power steering system having such a bearing end cap, and to a method for producing the electric motor.

Description

Technical Field

[0001] The present invention relates to a bearing end cap for an electric motor, particularly for a bearing end cap for or in an electric power steering system, an electric motor for an electric power steering system, and a method for manufacturing an electric motor, particularly for an electric power steering system. Background Technology

[0002] Although the present invention and the problem on which it is based will be described in more detail below in conjunction with an electric motor for an electric power steering system, the present invention is not limited thereto, but can be adapted to a wide variety of electric motors that require a sealing connection between the bearing end cap and the motor housing.

[0003] Also known as electromechanical steering, EPS (Electric Power Steering), or MDPS (Motor Driven Power Steering), electric power steering systems offer numerous advantages over traditional hydraulic power steering systems, particularly reduced fuel consumption, significant space savings, and lower integration costs. Furthermore, they enable improved driver experience through software control and even the implementation of driver assistance systems for automated driving. Of course, this is applicable to all types of vehicles equipped with electric power steering systems, including not only motor vehicles but also trucks, construction machinery, and racing cars.

[0004] CN217087639U describes an electric power steering system in which a housing is coupled to a bearing end cap via a flange connection and sealed by means of a surrounding O-ring arranged in a crease in the flange connection. The O-ring is positioned on the outer side of the flange region of the bearing end cap and on the inner side of the flange region of the housing. The axial end of the housing thus extends beyond the seal toward the bearing end cap and terminates on the bearing end cap after the seal. To ensure a tight seal during installation, a chamfer is provided at the flange-side end of the inner wall of the housing, into which the O-ring is fitted during installation. Summary of the Invention

[0005] In this context, the objective of this invention is to describe an improved sealing connection between the bearing end cap and the motor housing.

[0006] According to the present invention, this task is accomplished by a bearing end cap for an electric motor having the features of claim 1 and / or by an electric motor for an electric power steering system having the features of claim 6 and / or by a method for manufacturing an electric motor having the features of claim 9.

[0007] Based on this setting: - A bearing end cap for an electric motor, particularly for or in an electric power steering system, the bearing end cap having: a bearing section configured to support a motor shaft; and a sealing section configured for a sealing connection relative to a motor housing, wherein the sealing section has an axially oriented sealing groove relative to the bearing section, the sealing groove being configured to receive an axial seal and an axial edge section for receiving the motor housing, thereby compressing the seal.

[0008] - An electric motor for an electric power steering system, the electric motor having a bearing end cap according to the invention.

[0009] - A method for manufacturing an electric motor, particularly an electric motor according to the present invention, comprising the steps of: inserting a surrounding seal into an axially oriented sealing groove of a bearing end cap; inserting an axial edge of a motor housing into the sealing groove to compress the seal; and fastening the motor housing to the bearing end cap.

[0010] The present invention is based on the understanding that the housing section of the seal extending beyond the bearing end cap requires additional structural space, thereby increasing the overall axial structural dimensions of the electric motor.

[0011] The present invention is based on the idea that the motor housing terminates either by resting its axial end on the seal or by pressing the seal against it in the axial direction. For this purpose, a sealing groove is provided in the sealing section of the bearing end cover to receive the seal and fix it in all other translational degrees of freedom. In this way, the motor housing advantageously does not need to protrude beyond the seal, but terminates directly on it. Therefore, the protruding length of the motor housing is advantageously saved, and the motor housing and the entire motor can be constructed with a correspondingly shorter axial length.

[0012] For example, the motor housing can be locked to the bearing end cap material at the point where the seal is pressed. Therefore, simple installation is ensured while fully meeting sealing requirements.

[0013] Furthermore, according to the invention, structural reinforcement of the motor housing is provided by having the motor housing circumferentially housed within the sealing groove of the bearing end cap. In this way, the motor housing according to the invention can advantageously withstand higher loads, and / or be optimally constructed in terms of material input and weight. Overall, the power density of the electric motor is thus improved according to the invention, both in terms of total weight and the required structural space.

[0014] Advantageous design options and improvements are derived from the additional dependent claims and the description made with reference to the accompanying drawings.

[0015] According to one embodiment, the bearing section is constructed radially inner to the sealing section, and a flange area is provided radially outer, such that a sealing groove is arranged between the bearing section and the flange area. Advantageously, the seal is thus arranged independently of the flange area or its mounting point, and thus the sealing performance of the electric motor is ensured independently of its installation via the flange area.

[0016] According to one embodiment, a sealing groove is arranged at the shoulder of the sealing section. In this way, a structurally stable surrounding reception portion is provided for the edge section of the motor housing. This shoulder can advantageously be used simultaneously for the connection between the motor housing and the bearing end cap, for example, for a material-locking connection.

[0017] According to an improvement, the shoulder has a pre-formed portion for connecting the motor housing to the bearing end cover. For example, this pre-formed portion could be a weld pre-formed portion. According to another improvement, the pre-formed portion is constructed at the outer edge of the shoulder. In particular, the pre-formed portion is chamfered to optimize the material-locking connection, for example, to accommodate the volume of filler during welding.

[0018] According to one embodiment of the electric motor, a motor shaft, a motor housing housing the motor shaft, and a surrounding seal are provided. The seal is configured to seal the motor housing relative to a bearing end cap supporting the motor shaft and is received within a sealing groove in the bearing end cap. An axial edge of the motor housing is inserted into the sealing groove, and the motor housing is fastened to the bearing end cap such that the axial edge presses against the seal. In this way, the motor housing advantageously does not need to protrude beyond the seal, but terminates directly on the seal with its leading edge. This saves the length of the motor housing protruding beyond the seal and allows the motor housing and the entire motor to be constructed with a correspondingly shorter axial length. The surrounding reception of the motor housing within the sealing groove of the bearing end cap also provides structural reinforcement to the motor housing. In this way, the motor housing can advantageously withstand higher loads and / or is optimized in terms of material input and weight compared to conventional sealing methods.

[0019] According to an improved embodiment, the motor housing also has a radial shoulder that is material-lockingly connected to the shoulder of the sealing section. The radial shoulder extends radially outward beyond the motor housing. Therefore, the motor housing can be easily and easily material-lockingly connected to the bearing end cap. Furthermore, the radial shoulder of the motor housing can advantageously also serve as a stop, particularly relative to the shoulder of the bearing end cap, to apply a predetermined pressure to the seal without the risk of damaging the seal.

[0020] According to an improvement, the radial shoulder has a pre-formed portion for connecting the motor housing to the bearing end cover. Specifically, the shoulder of the bearing end cover and the radial shoulder of the motor housing have corresponding pre-formed portions. For example, this pre-formed portion can be a weld pre-formed portion. According to another improvement, the pre-formed portion is constructed at the outer edge of one or more shoulders. In particular, the pre-formed portion is chamfered to optimize the material locking connection, for example, to accommodate the volume of filler during welding.

[0021] According to one embodiment of the manufacturing method, an axially oriented sealing groove is formed in the shoulder of the sealing section of the bearing end cover, wherein the motor housing has a radial shoulder, and fastening the motor housing to the bearing end cover includes: material-lockingly connecting the shoulder of the motor housing to the shoulder of the bearing end cover. Therefore, the shoulder of the bearing end cover can advantageously be used not only to form the sealing groove, but also simultaneously for connecting the motor housing and the bearing end cover. The radial shoulder of the motor housing extends radially outward beyond the motor housing and preferably terminates flush with the shoulder of the bearing end cover. Furthermore, the radial shoulder of the motor housing can advantageously also additionally serve as a stop, particularly a stop relative to the shoulder of the bearing end cover, to apply a predetermined pressure to the seal without the risk of damaging the seal. Moreover, this thus provides an easily accessible joint for a material-locking connection (e.g., achieved by welding).

[0022] The above-described design schemes and improvements can be combined arbitrarily, provided they are reasonable. Other possible design schemes, improvements, and implementations of the present invention also include combinations of features of the invention not explicitly mentioned above or below that are described with reference to the embodiments. In particular, those skilled in the art will also add individual aspects here as improvements or additions to the corresponding basic forms of the present invention. Attached Figure Description

[0023] The invention will now be described in more detail with the aid of embodiments illustrated in the accompanying drawings. Wherein: Figure 1 A cross-sectional view of the bearing end cap is shown; Figure 2 A cross-sectional view of an electric motor is shown; Figure 3 It shows according to Figure 2 Detailed view of the sealed section of the electric motor; Figure 4 A flowchart of a method for manufacturing an electric motor is shown; and Figure 5 It shows according to Figure 4 A diagram illustrating the method.

[0024] These accompanying drawings are intended to facilitate a further understanding of embodiments of the invention. They illustrate embodiments and are used in conjunction with the description to explain the principles and concepts of the invention. Other embodiments and many of the advantages mentioned herein are derived from the drawings. Elements in the drawings are not necessarily shown to scale.

[0025] In the accompanying drawings, unless otherwise specified, the same, functionally identical, and identical elements, features, and components are given the same reference numerals. Detailed Implementation

[0026] Figure 1 A cross-sectional view of the bearing end cap 1 is shown.

[0027] The bearing end cap 1 is configured for use with the electric motor 10 (see...) Figure 2 In particular, the bearing end cap relates to a bearing end cap for an electric power steering system in a motor vehicle or a bearing end cap in an electric power steering system.

[0028] The bearing end cap 1 is constructed as a surrounding support structure and is used to distribute the load acting on the motor shaft. The bearing section 2 of the bearing end cap is configured to support the motor shaft 11 (see [reference]). Figure 2 For this purpose, the bearing section forms a radially inward portion of the bearing end cap 1 and has a bearing housing 3, which is configured to accommodate a suitable shaft bearing 19 (see [link to bearing housing]). Figure 2 (e.g., rolling bearings).

[0029] A flange region 7 is provided on the radially outer side of the bearing end cover 1. This flange region is provided only exemplarily with a hole 7A and is configured for fastening to the vehicle structure. In other embodiments, instead of the hole, various other types of fastening mechanisms may be provided in the flange region 7, of course, optionally or additionally.

[0030] A sealing section 4 of the bearing end cap 1 is radially disposed between the flange region 7 and the bearing section 2. The sealing section 4 is configured to be positioned relative to the motor housing 12 (see...). Figure 2 The sealing connection is configured for a tight seal relative to the motor housing 12. According to the embodiment shown here, the sealing section 4 is configured to accommodate a surrounding seal 5, such as an O-ring. For this purpose, the sealing section 4 has a surrounding sealing groove 6 oriented axially relative to the bearing section 2, in which the surrounding seal 5 can be accommodated.

[0031] Although seal 5 is shown here for better illustration, it is not part of bearing end cap 1. Instead, seal 5 is only present when connecting bearing end cap 1 to motor housing 12 of electric motor (see...). Figure 5They are only introduced into the sealing groove 6 when they are installed together.

[0032] A sealing groove 6 is arranged at the shoulder 8 of the sealing section 4. The shoulder 8 is configured for a structural connection between the bearing end cap and the motor housing, and therefore extends axially relative to the flange area 7. The sealing groove 6 is configured to accommodate the axial edge section 13 of the motor housing 12. This means that the edge at the open end of the motor housing 12 can be guided into the sealing groove 6. To ensure optimal sealing, the edge section 13 can be guided into the sealing groove 6 to such an extent that the seal 5 arranged in the sealing groove is compressed or can be compressed in a sealing manner. For this purpose, the sealing groove 6 has a depth exceeding the thickness or height of the seal 5.

[0033] Figure 2 A cross-sectional view of the electric motor 10 is shown.

[0034] It relates to an electric motor 10 for an electric power steering system, the electric motor having according to Figure 1 Bearing end cap 1.

[0035] The motor shaft 11 of the electric motor 10 is housed in the motor housing 12. A support portion for the motor shaft 11, provided by a suitable shaft bearing 19 (implemented here purely by way of example as a rolling bearing), is provided on one side at the closed end 15 of the motor housing 12 and on the other side in the bearing section 2 of the bearing end cover 1. A rotor 16 is mounted on the motor shaft 11, and a stator 17 is mounted on the motor housing 12.

[0036] The bearing end cover 1 is disposed at the open end 18 of the motor housing 12. A surrounding seal 5 is accommodated in the sealing groove 6 of the bearing end cover 1. The seal 5 is configured to seal the motor housing 12 relative to the bearing end cover 1.

[0037] The axial edge section 13 of the motor housing 12 is inserted into the sealing groove 6, thereby compressing the seal 5. The motor housing 12 has an outwardly extending radial shoulder 14 at the edge region, which is exemplarily configured here as a surrounding protrusion. The radial shoulder 14 serves as a stop cooperating with the shoulder 8 on the one hand, and on the other hand, it is material-locked to the shoulder 8 of the sealing section 4.

[0038] The radial shoulder 14 of the motor housing 12 is optional. Therefore, in other embodiments, alternative or additional fastening mechanisms for securing the motor housing 12 to the bearing end cover 1 and / or additional stop mechanisms for providing a predetermined compression of the seal 5 may also be provided.

[0039] Figure 3 It shows according to Figure 2Detailed view of the sealed section 4 of the electric motor 10.

[0040] Here, two shoulders 8 and 14 can be seen in detail. They act as stops relative to each other, thereby adjusting a predetermined gap between the end of the edge section 13 and the bottom of the sealing groove 6 to achieve a predetermined compression of the seal 5. The figure shows the state or predetermined deformation of the seal 5 being compressed accordingly in a predetermined manner, which causes the seal to fit completely against the sides and bottom of the sealing groove 6 without damaging the seal 5, thus providing a high level of sealing performance.

[0041] Furthermore, it can be seen that the edge section 13 of the motor housing 12 is slightly chamfered, that is, a relatively gentle chamfer 20 is constructed at the outer edge, which facilitates insertion into the sealing groove 6.

[0042] In the illustrated embodiment, a material-locking connection (not explicitly shown) is further provided between the bearing end cover 1 and the motor housing 12. This material-locking connection is constructed between the shoulder 8 of the bearing end cover 1 and the radial shoulder 14 of the motor housing 12. For this purpose, the shoulder 8 has a pre-formed portion 9 at its outer edge for material-locking connection between the motor housing 12 and the bearing end cover 1. In the illustrated embodiment, this pre-formed portion is exemplarily a chamfer for preparing the weld seam for the welded connection.

[0043] Figure 4 A flowchart is shown for a method of manufacturing an electric motor.

[0044] The method for manufacturing an electric motor 10 particularly relates to a method for manufacturing such as Figure 2 and Figure 3 The method shown is for an electric motor used in an electric power steering system.

[0045] The first step S1 of the method includes: inserting the surrounding seal 5 into the axially oriented sealing groove 6 of the bearing end cap 1.

[0046] The additional step S2 includes: guiding the axial edge segment 13 of the motor housing 12 into the sealing groove 6, so that the seal 5 is compressed.

[0047] The third step S3 includes: fastening the motor housing 12 to the bearing end cover 1.

[0048] Fastening the motor housing 12 to the bearing end cover 1 may include: material-lockingly connecting the motor housing and the shoulder 8 of the bearing end cover 1. For this purpose, an axially oriented sealing groove 6 is formed in the shoulder 8 of the sealing section 4 of the bearing end cover 1, wherein the motor housing 12 has a radial shoulder 14, and the shoulder 8 of the bearing end cover 1 is connected to the radial shoulder 14, for example, by welding.

[0049] If a radial shoulder 14 is provided, the radial shoulder 14 can stop the axially extending shoulder 8 of the bearing end cover 1, thereby limiting the introduction of the axial edge section 13 S2 to a predetermined degree of compression on the seal 5.

[0050] Figure 5 Additional information is provided regarding the basis Figure 4 A diagram illustrating the method.

[0051] The sealing element 5 is introduced into the sealing groove 6 through S1, and the edge segment 13 is introduced into the sealing groove 6 through S2, which are shown here in an exploded view of the components and symbolically indicated by arrows.

[0052] Although the present invention has been fully described above in conjunction with preferred embodiments, the present invention is not limited thereto, but can be modified in a variety of ways.

[0053] For example, instead of O-ring seals, various types of circumferential seals can be introduced into the sealing groove during installation or set in an electric motor. In particular, the seal can also be a non-solid seal that is introduced circumferentially into the sealing groove at the same time as the circumferential seal is introduced, such as a later-curing sealant. It is conceivable that the non-solid seal can be activated and / or cured, for example, by the heat introduced for material-locking connections (especially welding).

[0054] In the above embodiments, the bearing end cap 1 is shown only as an exemplary casting with a relatively large radius, wherein at least the sealing groove 6, the shoulder 8, and the bearing seat 3 are machined surfaces. However, in other embodiments, the bearing end cap 1 can of course be made in other ways, such as a milled part, an additively manufactured part, a pressed part, etc.

[0055] List of reference numerals

[0056] 1. Bearing end cover

[0057] 2 Bearing Section

[0058] 3 Bearing housing

[0059] 4. Sealed section

[0060] 5. Seals

[0061] 6 Sealing groove

[0062] 7 Flange area

[0063] 7A Hole

[0064] 8 shoulders

[0065] 9. Preparation section, chamfering

[0066] 10 Electric motors

[0067] 11 Motor Shaft

[0068] 12 Motor housing

[0069] 13 Edge Section

[0070] 14. Radial shoulder

[0071] 15 Closed end

[0072] 16 rotors

[0073] 17 Stator

[0074] 18 Open ends

[0075] 19-axis bearing

[0076] 20 chamfer

Claims

1. A bearing end cap (1) for an electric motor (10), particularly for a bearing end cap for an electric power steering system or in an electric power steering system, said bearing end cap having: Bearing section (2), said bearing section being configured to support motor shaft (11); and A sealing section (4) is configured for a sealing connection relative to the motor housing (12). in, The sealing section (4) has a surrounding sealing groove (6) oriented axially relative to the bearing section (2), the sealing groove being configured to accommodate the surrounding seal (5) and an axial edge section (13) of the motor housing (12), thereby compressing the seal (5).

2. The bearing end cap according to claim 1, Its features are, The bearing section (2) is constructed on the radially inner side of the sealing section (4) and a flange area (7) is provided on the radially outer side, so that the sealing groove (6) is arranged between the bearing section (2) and the flange area.

3. The bearing end cover according to any one of the preceding claims, Its features are, The sealing groove (6) is arranged at the shoulder (8) of the sealing section (4).

4. The bearing end cap according to claim 3, Its features are, The shoulder (8) has a preparatory portion (9) for connecting the motor housing to the bearing end cover.

5. The bearing end cap according to claim 3, Its features are, The preparatory part (9) is constructed at the outer edge of the shoulder (8), and is in particular constructed as a chamfer for material locking connection.

6. An electric motor (10) for an electric power steering system, the electric motor having a bearing end cap (1) according to any one of the preceding claims.

7. The electric motor according to claim 6, Its features are, The assembly also includes a motor shaft (11), a motor housing (12) housing the motor shaft, and a surrounding seal (5), wherein the seal (5) is configured to seal the motor housing (12) relative to a bearing end cap (1) supporting the motor shaft (11) and is received in a sealing groove (6) of the bearing end cap (1), wherein an axial edge segment (13) of the motor housing (12) is inserted into the sealing groove (6), and the motor housing (12) is fastened to the bearing end cap (1) such that the axial edge segment (13) presses against the seal.

8. The electric motor according to claim 6 or 7, Its features are, The bearing end cap (1) is constructed according to any one of claims 3 to 5, and the motor housing (12) has a radial shoulder (14) that is materially locked to the shoulder (8) of the sealing section (4).

9. A method for manufacturing an electric motor (10), particularly a method for manufacturing an electric motor for an electric power steering system according to any one of claims 6 or 7, the method comprising the following steps: The surrounding seal (5) is inserted (S1) into the axially oriented sealing groove (6) of the bearing end cap (1); The axial edge segment (13) of the motor housing (12) is inserted (S2) into the sealing groove (6) to compress the seal (5); and Secure the motor housing (12) to the bearing end cap (1) (S3).

10. The method according to claim 9, Its features are, The axially oriented sealing groove (6) is formed in the shoulder (8) of the sealing section (2) of the bearing end cover (1), wherein the motor housing (12) has a radial shoulder (14), and fastening the motor housing (12) to the bearing end cover (1) (S3) includes: materially locking the shoulder (14) of the motor housing to the shoulder (8) of the bearing end cover (1).

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