Improved positive locking connections for joining housing parts of an electromechanical brake and methods for their manufacture

Abstract

Method for connecting a power housing and a motor housing of an electromechanical brake device (01), in particular for use in a motor vehicle, wherein the power housing (02) is configured to at least partially accommodate a threaded drive (03), preferably a ball screw drive, and wherein the motor housing (04) is configured to accommodate an electric drive motor together with a transmission unit (06), preferably a motor worm, meshing with the threaded drive (03), wherein the power housing (02) and the motor housing (04) are brought into a connection position in which material of the motor housing (04) is formed from the outside into a groove (07) formed on an outer surface (08) of the power housing (02) to form a positive locking connection.

Description

Technical field

[0001] The invention relates to a method for manufacturing electromechanical braking devices, particularly for use in a motor vehicle. The invention further relates to an electromechanical braking device, particularly for use in a motor vehicle. State of the art

[0002] Hydraulically actuated disc brakes have long been known and widely used in the automotive sector and other areas. With the increasing electrification of vehicles, electromechanical braking devices have also been proposed more frequently in the past. These devices generate or provide braking force based on an electromechanical mechanism. Advantageously, a rotary motion, such as that of an electric motor, can be converted into a translational motion by means of a screw drive, which then generates a braking force, for example, in front of brake pads on a brake disc. The prior art already provides for arranging the electric motor and the screw drive in a common housing to enable a compact design.Since parts of the housing, particularly in the area of ​​the threaded drive and its support or bearing, are subjected to high forces and loads during every braking operation, housings in the prior art are regularly made of very strong but also relatively heavy steel, for example as turned parts. This has the disadvantage that the electromechanical braking device is relatively heavy overall.

[0003] DE 102 50 843 A1 describes a wiper bearing for a wiper shaft of a windshield wiper system and an associated manufacturing process. The end of a retaining tube is connected to a fastening section, for which purpose the fastening section has a pin-tube receptacle that also includes radial openings through which material from the tube end is crimped into the fastening section to secure or fasten the tube end to the fastening section.

[0004] From DE 10 2009 055 340 A1, a motor vehicle valve module and a method for manufacturing a valve module are known, in which a housing cap is attached to the base body by means of a local plastic deformation of material of the housing cap into a recess of a base body.

[0005] Against this background, the object of the present invention is to overcome the disadvantages of the prior art. Disclosure of the invention

[0006] The inventive method for connecting a power housing and a motor housing of an electromechanical brake device, in particular for use in a motor vehicle, enables a safe and reliable formation of a positive locking connection by molding material, whereby the positive locking connection is reliably achieved with the simplest preparation and / or pre-processing steps by molding material in the correct position and to the correct extent, preferably independently of the general shape of the body whose material is deformed.

[0007] In the method for connecting a power housing and a motor housing of an electromechanical braking device, particularly for use in a motor vehicle, where the power housing is configured to at least partially accommodate a threaded drive, preferably a ball screw drive, and where the motor housing is configured to accommodate an electric drive motor together with a transmission unit meshing with the threaded drive, preferably a motor worm gear, it is provided that the power housing and the motor housing are brought into a connection position in which material from the motor housing is formed from the outside into a groove formed on an outer surface of the power housing to create a positive-locking connection between the power housing and the motor housing. In other words, a crimp connection is formed between the motor housing and the power housing.

[0008] According to the invention, it is provided that an embossed contour projecting outwards towards an adjacent reference surface is formed inwards on an outer surface of the motor housing, the reference surface serving as a stop for a forming tool.

[0009] The present invention has recognized in a particularly surprising way that it is possible to create a positive locking connection between the motor housing and the power housing with particular accuracy and precision – especially with regard to the location, circumference, and extent of the deformed material – by means of inwardly displaced material from the motor housing. This is achieved, on the one hand, by providing an embossing contour that supplies the molded or displaced material, and on the other hand, by forming a reference surface in the vicinity of the embossing contour that serves as a stop for a forming tool, for example, a forming die. This ensures that the forming tool is driven reliably to an end position and not beyond.because the reference surface forms the stop for the forming tool and simultaneously displaces and / or forms a precisely defined shape and quantity of material, because the part of the embossing contour projecting beyond the reference surface, or the entire embossing contour surrounded or enclosed by the reference surface, is formed inwards and used to form the positive locking connection.

[0010] As will be explained in more detail in the description of exemplary embodiments, this method has the particular advantage that both the reference surfaces and the embossing contour can be largely freely defined, making the method highly flexible and applicable to a wide variety of shapes, geometries, and other properties of the motor housing. This, in turn, allows the motor housing to be designed largely free from constraints imposed by the production of the positive-locking connection.

[0011] Advantageous further developments of the method according to the invention are listed in the dependent claims.

[0012] In a first, preferred embodiment, the reference surface and the embossed contour can be formed as a recessed contour relative to an outer surface of the motor housing, and in particular, machined. This has the advantage that the remaining wall thickness of the motor housing outside the reference surface and the embossed contour can be chosen largely arbitrarily, and in particular, can be chosen such that this surrounding wall thickness is too large or thick to form a positive-locking connection by molding in material.

[0013] In a further, particularly advantageous embodiment, it can also be provided that the reference surface and the embossed contour are produced by a common machining step, preferably by drilling with a step drill or finishing cutter. This allows both the reference surface and the embossed contour to be produced in a particularly simple and effective manner in a single process step.

[0014] In a further, particularly advantageous embodiment, the forming tool can be designed to completely deform the embossed contour to the level of the reference surface. This can be especially advantageous when the reference surface completely encloses or surrounds the embossed contour. In this case, the forming tool, particularly a forming die, can be dimensioned such that it has a contact or stamping surface that is larger overall than the embossed contour and, particularly advantageously, corresponds to the surface and contour of the reference surface—which itself can be either flat or curved—so that the forming tool then completely deforms the embossed contour to the surrounding level of the reference surface. This allows, to a particularly advantageous extent, simple visual verification of the successful formation of the positive-locking connection.If, after the formation of the positive locking connection, parts of the embossed contour are still recognizable or can be felt / measured as a raised structure, it can be assumed that the positive locking connection may not have been formed correctly or not with certainty.

[0015] In an alternative embodiment of the process, the molding tool can also be designed so that it only partially deforms the embossed contour to the level of the reference surface. This allows for greater freedom or flexibility in positioning the components, particularly the engine housing, relative to the molding tool. If the embossed contour is so large or has such an extent that only a portion of it is deformed to the level of the reference surface, the positioning of the engine housing relative to the molding tool can vary within the area where the embossed contour extends.

[0016] Furthermore, it can be particularly advantageous to provide that by forming the material of the motor housing into the groove in the radial direction, the motor housing and the power housing, in particular in the axial direction, are subjected to force and / or pre-tensioned into the connection position, for which purpose the groove has a bottleneck cross-section.By designing the groove preferably with a part of the groove wall that is angled or chamfered to the radial direction and which also advantageously transitions into a radius change, it can be achieved in a particularly advantageous way that, when forming the material, although the forming direction of the forming tool is exclusively or largely in the radial direction, a force or force component is also generated in the axial direction by the formed tool which hits the bottleneck cross-section of the groove of the power housing, wherein the bottleneck cross-section is oriented such that the motor housing is subjected to force and / or preloaded in the axial direction against the power housing.This ensures that the housing, comprising the motor housing and the power housing, which is connected via the positive locking connection, is securely and reliably connected and remains connected in the connection position, thereby advantageously ensuring the safe and reliable engagement or meshing engagement between the threaded drive on the one hand and the transmission unit, preferably the motor worm, on the other.

[0017] The present invention also comprises an electromechanical braking device, preferably manufactured according to one of the methods described above and particularly intended for use in a motor vehicle, wherein a threaded drive, preferably a ball screw drive, is at least partially accommodated in a power housing and wherein an electric drive together with a transmission unit, preferably a motor worm gear, meshing with the threaded drive in a connected state is accommodated in a motor housing, wherein the power housing and the motor housing are fastened or connected to each other by means of a positive locking connection, which is formed by externally molded material of the motor housing into a groove formed on an outer surface of the power housing.

[0018] According to the invention, a molding surface, flat relative to an adjacent reference surface, is formed on an outer surface of the motor housing in the area of ​​the molded material. As already described above in connection with the method according to the invention, the reference surface is used as a stop for a molding tool, thus ensuring that an embossed contour or a well-defined part of an embossed contour is deformed inwards, thereby forming the positive-locking connection. This creates a flat molding surface in the area of ​​the reference surface, in the area where the deformed embossed contour or a part of this embossed contour was previously located or formed. The molding surface preferably extends at the level of the reference surface. By appropriately selecting and shaping the molding tool, the molding surface can seamlessly and / or without transition continue the reference surface after the positive-locking connection has been formed.

[0019] Regarding the effects and advantages of the electromechanical braking device, reference is made to the preceding disclosure of the method according to the invention.

[0020] Advantageously, the forming surface and the reference surface can be designed to be recessed relative to an outer surface of the motor housing, preferably as a blind hole. This ensures that a correspondingly advantageous positive-locking connection can be achieved even with motor housings that otherwise have a greater wall thickness.

[0021] In a further, particularly advantageous embodiment, an embossed contour, preferably interrupted by the molding surface and raised or elevated above the reference surface, can be arranged adjacent to the reference surface. This embodiment, with an embossed contour partially interrupted by the molding surface at the level of the reference surface, can be implemented particularly when an initially produced embossed contour is larger in at least one spatial direction or dimension than the molding tool used to create the positive fit or the positive-locking connection. In this case, the remnants of the embossed contour can form a particularly good contrast to the molding surface, thus making it easy to recognize whether the positive-locking connection is or was formed correctly.

[0022] It is further advantageous to provide for several positive-locking connections between the motor housing and the power housing. This particularly benefits the reduction of the load on each individual positive-locking connection and increases the overall stability of the connection across the individual positive-locking connections. For example, the positive-locking connections can be arranged evenly distributed in a circumferential direction. For instance, four indentations can be formed, each with an angular offset of approximately 90° in the circumferential direction, each forming a corresponding individual positive-locking connection.

[0023] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments of the invention and from the drawings. Brief description of the drawings Fig. 1: a perspective view of a generic electromechanical braking device; Fig. 2: a section of an electromechanical braking device according to the invention in a first embodiment; Fig. 3: shows an alternative representation of the device of Fig. 2 before the formation of a positive locking connection; Fig. 4: shows a section of the device of the Fig. 2 and Fig. 3 after forming a positive locking connection; Fig. 5: shows an electromechanical braking device according to a second embodiment according to the invention; Fig. 6: shows an electromechanical braking device according to a third embodiment according to the invention; Fig. Figure 7 shows an enlarged section of the electromechanical braking device of the Fig. 6 Fig. Figure 8 shows an enlarged section of a cross-section through a power housing. Embodiments of the invention

[0024] Identical elements or elements with the same function are marked with the same reference symbols in the figures.

[0025] The Fig. Figure 1 shows an electromechanical brake device 01, which accommodates a power housing 02 with a partially enclosed and mounted threaded drive 03 and a motor housing 04, which accommodates an electric motor 05 and the transmission unit 06 driven by the electric motor, for example in the form of a motor worm. In the illustration of the Fig. Figure 1 shows a transparent front part of the motor housing 04. This part of the motor housing 04 can advantageously be made of or have an aluminum surface. It is evident that there is a partial tube overlap between the power housing 02 and the front part of the motor housing 04. To connect the motor housing 04 to the power housing 02, a positive-locking connection, in particular a crimp connection, can be formed, which, however, is not shown in the illustration. Fig. 1 is not shown in detail.

[0026] In the Fig. Figure 2 shows an electromechanical brake device 01 according to the invention, in which the front part of the motor housing 04 is also shown transparently. In the illustration of the Fig. 2. It is also apparent that the power housing 02 has a groove 07 on an outer surface 08. Already in the Fig. 2 in the transparent representation it is recognizable or at least indicated that on the outer surface 09 of the motor housing 04 there is an embossed contour 10 - in the example of the Fig. 2 in the form of an elongated embossed strip - wherein the embossed contour 10 is formed projecting outwards towards an adjacent reference surface 11.

[0027] In the Fig. 3 is the device of the Fig. 2 shown in a different view. Furthermore, for better illustration, the front part of the engine housing 04 is shown in contrast to the Fig. 2 not shown transparently. In this representation it is even more apparent that the outer surface 09 of the motor housing 04 forms the reference surface 11 above which the embossed contour 10 rises or over which the embossed contour 10 projects. The representation of the Fig. Figure 3 shows a state before the formation of the positive locking connection.

[0028] The Fig. Figure 4 shows another, slightly different representation of the same component, but after the creation of a positive-locking connection by molding material from the motor housing 04 from the outside into the groove 07 of the power housing 02. As in the Fig. As shown in Figure 4, part of the embossed contour 10 was deformed inwards to the level of the reference surface 11, thereby forming a molding surface 12 that is flat or uniform with respect to the reference surface 11. This molding surface 12, which may be curved in one or more directions but nevertheless runs without offset to the reference surface 11 and is at the same level as the reference surface 11, is formed by using a molding tool, in particular a punch, when molding the material of the motor housing 04 inwards. This tool uses the reference surface 11 as a stop and otherwise follows the shape of the reference surface 11, as shown by the curvature in the example of Figure 4. Fig. 4 in the area of ​​the molding surface 12 can be seen.

[0029] The stamp or molding tool that is in the Fig. The area not shown (4) can be higher than the embossing contour 10. The embossing contour 10, which is interrupted in the area of ​​the forming surface 12, allows for visual, machine-based or manual inspection to ensure the correct formation of the interlocking connection. Furthermore, the reference surface 11, acting as a stop surface or stop for the forming process or the inward deformation of the material, ensures that material can only be deformed inwards in the area of ​​the embossing contour and only to the extent of the embossing contour's projection relative to the reference surface, thus ensuring that material is deformed inwards at the correct location and to the correct extent.

[0030] The Fig. Figure 5 shows an alternative embodiment. Here, the front section of the motor housing 04 is modified compared to the embodiment of the Fig. The wall thickness in the area surrounding the positive-locking connection is 2 to 4 times greater. To ensure a reliable and secure positive-locking connection, both the reference surface 11 and the embossed contour 10, which can be designed, for example, as a round or elongated embossing point, are formed as recessed contours relative to the outer surface 09 of the motor housing 04. The illustration of the Fig. Figure 5 also shows an example of a state before joining motor housing 04 and power housing 02, in which the embossed contour 10 is still recognizable as raised or protruding above the reference surface 11.

[0031] The reference surface 11, designed as a blind hole, including the embossed contour 10, can be produced, for example, in a single machining step. Due to the recessed or offset reference surface 11, the positive-locking connection can be reliably and securely created by forming or deforming the embossed contour 10 inwards, because the remaining wall thickness in the area of ​​the reference surface 11 and the embossed contour 10 is correspondingly reduced. In the embodiment of the Fig. 5. The embossed contour 10 is completely enclosed, bounded, or framed by the reference surface 11. In such an embodiment, it can be provided that, during the formation of the positive-locking connection, the forming tool completely deforms the embossed contour 10 to the level of the reference surface 11. In this case, after joining the motor housing 04 and the power housing 02, only a preferably uniform, for example, flat, reference surface 11 remains, along with an enclosed forming area.

[0032] In the Fig. Figure 6 shows an alternative embodiment in which the reference surface 11 and the embossing contour 10 are designed as recessed surfaces relative to the outer surface 09 of the motor housing 04. The corresponding blind hole can be produced, for example, with a step drill or a finishing cutter in a single process step.

[0033] In the Fig. 7 is the reference surface 11 and the embossing contour 10 of the embodiment of the Fig. Figure 6 is shown enlarged again. It can also be advantageous to provide that these are designed as angled bores, which allows a particularly advantageous adaptation to the other geometry of the electromechanical brake devices 01 and in particular the shape and geometry of the motor housing 04.

[0034] The presentation of Fig. Figure 7 illustrates a situation in which the positive-locking connection has not yet formed and the embossed contour 10 is therefore still recognizable as a protruding embossed contour relative to the reference surface 10. After the material of the embossed contour 10 is formed inwards, with the reference surface 11 serving as a stop for the forming tool, an uninterrupted plane or curved surface may remain after the positive-locking connection between motor housing 04 and power housing 02 has thus been formed. This surface then encompasses both the reference surface and the forming surface on which the embossed contour 10 was previously located.

[0035] Fig.Figure 8 shows an advantageous embodiment of the design of the groove 07. The illustrated section through a part of a power housing 02 shows that the groove 07 extends over a chamfered area 14 and an adjacent radius transition 15 in the area of ​​the groove wall 16, forming a bottleneck cross-section through which, when material is formed in the radial direction R, the motor housing 04 and the power housing 02 are subjected to force and / or pre-tensioned into the connection position and thus in the axial direction A. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 102 50 843 A1

[0003] DE 10 2009 055 340 A1

[0004]

Claims

[1] Method for connecting a power housing and a motor housing of an electromechanical braking device (01), in particular for use in a motor vehicle, wherein the power housing (02) is configured to at least partially accommodate a threaded drive (03), preferably a ball screw drive, and wherein the motor housing (04) is configured to accommodate an electric drive motor together with a transmission unit (06), preferably a motor worm, meshing with the threaded drive (03), wherein the power housing (02) and the motor housing (04) are brought into a connection position in which material of the motor housing (04) is formed from the outside into a groove (07) formed on an outer surface (08) of the power housing (02) to form a positive locking connection. characterized by, that on an outer surface (09) of the motor housing (04) an embossed contour (10) projecting outwards relative to an adjacent reference surface (11) is formed inwards, the reference surface (11) serving as a stop for a forming tool. [2] Method according to claim 1, characterized by , that the reference surface (11) and the embossing contour (10) are formed as a recessed contour opposite an outer surface (08,09) of the motor housing (04), in particular by machining. [3] Method according to claim 1 or 2, characterized by , that the embossing contour (10) and the reference surface (11) are produced by a common machining step, preferably by drilling with a step drill. [4] Method according to any one of claims 1 to 3, characterized by , that the molding tool completely deforms the embossing contour (10) to a level of the reference surface (11). [5] Method according to any one of claims 1 to 3, characterized by that the molding tool only partially deforms the embossing contour (10) to a level of the reference surface (11). [6] Method according to any one of claims 1 to 5, characterized by , that by forming the material of the motor housing (04) into the groove (07) in radial direction (R) the motor housing (04) and the power housing (02) are subjected to force and / or pre-tensioned into the connection position, for which purpose the groove (07) has a bottleneck cross-section. [7] Electromechanical braking device (01), in particular for use in a motor vehicle, in particular manufactured by a method according to one of claims 1 to 6, wherein a threaded drive (03), preferably a ball screw drive, is at least partially received in a power housing (02) and wherein an electric drive motor together with a transmission unit (06), preferably a motor worm, meshing with the threaded drive (03) is received in a motor housing (04), wherein a positive locking connection is formed by externally molded material of the motor housing (04) into a groove (07) formed on an outer surface (08) of the power housing (02). characterized by , that on an outer surface (09) of the motor housing (04) in the area (14) of the molded material a molded surface (12) is formed which is flat relative to an adjacent reference surface (11). [8] Electromechanical braking device (1) according to claim 7, characterized by , that the molded surface (12) and the reference surface (11) are recessed relative to an outer surface (09) of the motor housing (04), preferably as a blind hole. [9] Electromechanical braking device (1) according to one of claims 7 or 8, characterized by , that adjacent to the reference surface (11) an embossing contour (10) is arranged, preferably interrupted by the molding surface (12) and raised above the reference surface (11). [10] Electromechanical braking device (1) according to any one of claims 7 to 9, characterized by , that several positive locking connections are formed between the motor housing (04) and the power housing (02),

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