Improved form-fitting connections for connecting housing parts of an electromechanical brake, and method for producing same

Abstract

The invention relates to a method for connecting a power housing and a motor housing of an electromechanical brake device (01), in particular for use in a motor vehicle. The power housing (02) is designed to at least partly receive a screw drive (03), preferably a ball screw drive, and the motor housing (04) is designed to receive an electric drive motor together with a transmission unit (06), preferably a motor worm, which meshes with the screw drive (03) in a connected state. The power housing (02) and the motor housing (04) are brought into a connecting position in which material of the motor housing (04) is molded from the outside into a groove (07), which is formed in the outer surface (08) of the motor housing (02), in order to form a form-fitting connection.

Description

[0001] R. 415244

[0002] - 1 -

[0003] Description

[0004] Improved positive locking connections for joining housing parts of an electromechanical brake and methods for their manufacture

[0005] Technical field

[0006] 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.

[0007] State of the art

[0008] 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. This translational motion then generates a braking force, for example, against 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, especially in the area of ​​the threaded drive and its support or bearing, are subjected to high forces and loads during every braking process, the housings are regularly designed according to R. 415244.

[0009] - 2 - moderately manufactured from very stable but also relatively heavy steel, for example as a turned part. This has the disadvantage that the electromechanical braking device is relatively heavy overall.

[0010] 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.

[0011] From DE 102009 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.

[0012] Against this background, the object of the present invention is to overcome the disadvantages of the prior art.

[0013] Disclosure of the invention

[0014] 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.

[0015] In the method for connecting a power housing and a motor housing of an electromechanical brake device, in particular for use in a motor vehicle, where the power housing is designed to at least partially accommodate a threaded drive, preferably a ball screw drive, R. 415244

[0016] - 3 - and in which the motor housing is configured to receive an electric drive motor together with a transmission unit, preferably a motor worm, meshing with the screw drive in a connected state, 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.

[0017] 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.

[0018] 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.

[0019] As will be explained in more detail in connection with the description of exemplary embodiments, this method has in particular R. 415244

[0020] - 4 -

[0021] The advantage is that both the reference surfaces and the embossing contour are largely freely definable, making the process 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.

[0022] Advantageous further developments of the method according to the invention are listed in the dependent claims.

[0023] 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.

[0024] 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.

[0025] In a further, particularly advantageous embodiment, the forming tool can be designed to completely deform the embossing contour to the level of the reference surface. This can be particularly advantageous if the reference surface completely encloses or surrounds the embossing contour. In this case, the forming tool, especially a forming die, can be dimensioned such that it has a contact or stamping surface that is larger overall than the embossing contour and particularly advantageously corresponds to the surface and course of the reference surface—which in turn is so- R. 415244

[0026] - 5 - 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 for particularly advantageous, simple visual verification of the successful formation of the positive fit. If, after the positive fit has been formed, parts of the embossed contour are still recognizable or can be felt / measured as a raised structure, it can be assumed that the positive fit may not have been formed correctly or with certainty.

[0027] 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.

[0028] 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 portion of the groove wall that is angled or chamfered to the radial direction and that advantageously transitions into a radius change, it can be achieved particularly advantageously that, during the forming of the material, even though the forming direction of the forming tool is exclusively or largely radial, a force or force component is also generated in the axial direction by the formed tool, which encounters the bottleneck cross-section of the groove of the power housing. The bottleneck cross-section is oriented such that the motor housing is subjected to force and / or pre-tensioned in the axial direction against the power housing. This ensures that the housing, comprising the motor housing and the power housing, is securely and reliably connected and remains connected in the connection position via the positive-locking connection, thus advantageously ensuring the safety of R. 415244.

[0029] - 6 - 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, can be ensured.

[0030] 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.

[0031] 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.

[0032] Regarding the effects and advantages of the electromechanical braking device, reference is made to the preceding disclosure of the method according to the invention. R. 415244

[0033] - 7 -

[0034] 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.

[0035] 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.

[0036] It is further advantageous to provide for multiple 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.

[0037] 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.

[0038] Brief description of the drawings R. 415244

[0039] - 8 -

[0040] Fig. 1 : a perspective view of a generic electromechanical braking device;

[0041] Fig. 2: a section of an electromechanical braking device according to the invention in a first embodiment;

[0042] Fig. 3: shows an alternative representation of the device of Fig. 2 before the formation of a positive locking connection;

[0043] Fig. 4: shows a section of the device of Figs. 2 and 3 after forming a positive locking connection;

[0044] Fig. 5: shows an electromechanical braking device according to a second embodiment according to the invention;

[0045] Fig. 6: shows an electromechanical braking device according to a third embodiment according to the invention;

[0046] Fig. 7: shows an enlarged section of the electromechanical braking device of Fig. 6.

[0047] Fig. 8: shows an enlarged section of a cross-section through a power housing.

[0048] Embodiments of the invention

[0049] Identical elements or elements with the same function are marked with the same reference symbols in the figures.

[0050] Fig. 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 gear. In the illustration of Fig. 1, a front part of the motor housing 04 is shown transparently. This part of the motor- R. 415244

[0051] - 9 - Housing 04 can advantageously be made of or comprise aluminum material. It can be seen 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 detail in the illustration of Fig. 1.

[0052] 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. Figure 2 also shows that the power housing 02 has a groove 07 on an outer surface 08. Even in the transparent view of Figure 2, it is apparent, or at least indicated, that an embossed contour 10 – in the example of Figure 2 in the form of an elongated embossed strip – is formed on the outer surface 09 of the motor housing 04, the embossed contour 10 projecting outwards relative to an adjacent reference surface 11.

[0053] Figure 3 shows the device of Figure 2 from a different view. Furthermore, for better illustration, the front part of the motor housing 04 is not shown transparently, unlike in Figure 2. In this view, 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 is raised or over which the embossed contour 10 projects. The illustration in Figure 3 shows a state before the formation of the positive-locking connection.

[0054] Fig. 4 shows another, slightly different representation of the same component, but after the formation of a positive-locking connection by forming material from the motor housing 04 into the groove 07 of the power housing 02 from the outside. As shown in Fig. 4, part of the embossed contour 10 was deformed inwards to the level of the reference surface 11, thereby forming a forming surface 12 that is flat or uniform with respect to the reference surface 11. This forming 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 forming an R. 415244 inwards with the material of the motor housing 04.

[0055] - 10 -

[0056] A molding tool, in particular a punch, is used which uses the reference surface 11 as a stop and otherwise follows the shape of the reference surface 11, as can be seen from the curvature in the example of Fig. 4 in the area of ​​the molding surface 12.

[0057] The die or forming tool, which is not shown in Fig. 4, can be taller 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 guaranteeing that material is deformed inwards at the correct location and to the correct extent.

[0058] Figure 5 shows an alternative embodiment. Here, the front section of the motor housing 04 has a greater wall thickness in the area surrounding the positive-locking connection compared to the embodiment shown in Figures 2 to 4. To ensure a reliable positive-locking connection nonetheless, 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 a recessed contour relative to the outer surface 09 of the motor housing 04. Figure 5 also shows an example of a state before the motor housing 04 and power housing 02 are joined, in which the embossed contour 10 is still recognizable as raised or projecting above the reference surface 11.

[0059] The reference surface 11, designed as a blind hole, together with the embossed contour 10, can be produced, for example, in a single machining operation. 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 shown in Fig. 5, the embossed contour 10 is completely enclosed, bounded, or framed by the reference surface 11. (See R. 415244.)

[0060] - 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 reference surface 11, preferably uniform, for example flat, remains, together with an enclosed forming area.

[0061] 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.

[0062] Figure 7 shows an enlarged view of the reference surface 11 and the embossed contour 10 of the embodiment shown in Figure 6. Advantageously, these can also be designed as angled bores, which allows for a particularly advantageous adaptation to the overall geometry of the electromechanical brake devices 01 and, in particular, to the shape and geometry of the motor housing 04.

[0063] Figure 7 also 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 has been 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.

[0064] Fig. 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 R. 415244

[0065] - 12 - and the power housing 02 is moved into the connection position and thus subjected to force and / or pre-tensioned in axial direction A.

Claims

R. 415244 - 13 - Claims 1. 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, characterized in thatthat an embossed contour (10) projecting outwards towards an adjacent reference surface (11) is formed inwards on an outer surface (09) of the motor housing (04), the reference surface (11) serving as a stop for a forming tool.

2. Method according to claim 1, characterized in that the reference surface (11) and the embossing contour (10) are formed as a recessed contour relative to an outer surface (08,09) of the motor housing (04), in particular by machining.

3. Method according to claim 1 or 2, characterized in that the embossing contour (10) and the reference surface (11) are produced by a common machining step, preferably by drilling with a step drill. R. 415244 - 14 - 4. Method according to one of claims 1 to 3, characterized in that the forming tool completely deforms the embossing contour (10) to a level of the reference surface (11).

5. Method according to one of claims 1 to 3, characterized in that the forming tool only partially deforms the embossing contour (10) to a level of the reference surface (11).

6. Method according to one of claims 1 to 5, characterized in that by forming the material of the motor housing (04) into the groove (07) 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, 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) in a connected state 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 in that the molded material on an outer surface (09) of the motor housing (04) forms a molded-in surface (12) that is flat relative to an adjacent reference surface (11). R. 415244 - 15 - 8. Electromechanical braking device (1) according to claim 7, characterized in 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 in that a, preferably by the The embossing contour (10) is arranged in a form-fitting surface (12) that interrupts the reference surface (11).

10. Electromechanical braking device (1) according to one of claims 7 to 9, characterized in that several positive locking connections are formed between motor housing (04) and power housing (02),

Images