Improved connection between main bearing and housing of an electromechanical braking device, especially for vehicles and methods for its manufacture

Abstract

Method for joining a main bearing (01) and a housing (02) of an electromechanical brake device, in particular for use in a motor vehicle, wherein the brake device has an electromechanical drive unit comprising a threaded drive, preferably a ball screw drive, mounted in the housing (02), wherein the main bearing is mounted in the housing (02). (01) of the threaded drive is attached in an axial direction (A).

Description

Technical field

[0001] The present invention relates to a method for joining a main bearing and a housing of an electromechanical brake device, particularly for use in a motor vehicle. Furthermore, the present invention relates to an electromechanical brake device, particularly for use in a motor vehicle, in which the joining of the main bearing and housing is preferably carried out using the method according to the invention. State of the art

[0002] In the past, hydraulically actuated disc brakes were the predominant type used in motor vehicles. More recently, electromechanical braking systems have become increasingly common. In these systems, an electromechanical drive, such as an electric motor, provides a rotational movement, which is then converted into a translational movement by means of a threaded drive. This translational movement then causes the brake shoes to move relative to one or more brake discs, thus generating the braking effect. Because the threaded drive provides the actuating force for moving the brake shoes and pressing them against the brake disc, the drive mechanism and its main bearing, which is housed in a casing, are subjected to high loads. The connection between the casing and the main bearing of the threaded drive experiences every single braking force during every braking or deceleration operation.

[0003] It is already known in the art to use a steel housing into which the main bearing of the threaded drive is inserted. To secure or fasten the main bearing in the housing, the prior art provides for a steel riveting of the housing onto the bearing or a bearing edge. While this results in a secure fastening of the main bearing in the housing, which can then withstand the high loads during braking or deceleration processes in the long term, it requires complex manufacturing processes because particularly high riveting forces must be applied, necessitating large presses. Furthermore, with the known fastening or securing of the main bearing in the housing via riveting, the choice of housing material is severely limited, especially to high-strength steels.

[0004] From US 6,106,156 A, a device for fastening rings of a rolling bearing is known, in which a housing part is inserted at its end sides into a gap between the rings of the bearing and is formed there, in particular radially expanded section by section, in order to connect the rings to each other or to secure them to each other.

[0005] Against this background, the object of the present invention is to overcome the disadvantages in the prior art and in particular to produce a corresponding stable securing of the main bearing of the threaded drive of an electromechanical brake device in a housing, in particular without having to resort to high-strength steels and steel crimping. Disclosure of the invention

[0006] The inventive method for joining a main bearing and a housing of an electromechanical brake device makes it possible to use other materials, in particular brittle materials such as cast iron, for the housing and also enables the fastening or securing of the main bearing in said housing with less force, thus enabling energy, cost and effort reduction.

[0007] The inventive method for joining a main bearing and a housing of an electromechanical brake device, in particular for use in a motor vehicle, in which the brake device has an electromechanical drive unit comprising a threaded drive mounted in the housing, preferably a ball screw drive, wherein the main bearing of the threaded drive is fixed in the housing in an axial direction, provides the inventive method step of pressing a compression ring into an axially extending groove between an inner surface of the housing and an outer surface of the main bearing.

[0008] The compression ring can advantageously be made of a softer material, such as mild steel or aluminum, so that on the one hand, relatively easy pressing in and, if necessary, upsetting by means of a bulk forming process are possible, while at the same time the compression ring, in the pressed-in state, creates such a stable positive fit between the housing and the main bearing that the high loads of the connection between the housing and the main bearing can be well absorbed and dissipated. A particular advantage of the invention is that only the compression ring is formed and that the other joining partners, in particular the housing and the main bearing, are each designed as steel bodies, which also allows other materials, such as cast iron, to be used for the housing in addition to high-strength steels.Another special advantage is that the connection using the compression ring can be implemented in a space-saving manner, because the overhang on the housing side required for caulking in the prior art can be eliminated.

[0009] In a first, advantageous embodiment of the method, the compression ring can be radially expanded section by section during pressing, the expansion being defined and / or limited by a frustoconical groove section between the inner surface of the housing and the outer surface of the main bearing. The radial expansion of the compression ring into the corresponding frustoconical groove section results in a particularly stable connection between the main bearing and the housing.

[0010] In a further preferred embodiment of the method, the compression ring can be pressed in until it reaches the bottom of the groove. This ensures that a stable connection is established between the main bearing and the housing.

[0011] In a further particularly preferred embodiment of the method, the compression ring can be compressed flush with the top surface of the main bearing, particularly at the end of the press-fit process, whereby any material of the compression ring protruding beyond the top surface of the main bearing is displaced into a reservoir section of the groove located at the axial end. Compressing the compression ring improves the connection between the main bearing and the main bearing and also ensures that the connection remains space-neutral, as any protruding material of the compression ring does not remain protruding but is instead deformed or displaced into the reservoir section of the groove.

[0012] During press-fitting, it can be particularly advantageous to provide for the compression ring to be compressed in or within the groove, preferably successively from the bottom, i.e., starting from the groove base, upwards. For this purpose, the width of the groove can increase accordingly from bottom to top. In other words, as described below, an end section of the groove adjacent to the groove base can have a taper. This further improves the positive fit between the inner surface of the housing and the outer surface of the main bearing.

[0013] The present invention also includes an electromechanical braking device, in particular for use in a motor vehicle, wherein the braking device has an electromechanical drive unit comprising a threaded drive mounted in a housing, preferably a ball screw drive, wherein a main bearing of the threaded drive is fixed in the housing in an axial direction, in particular according to one of the methods described above.

[0014] According to the invention, a pressed-in compression ring is arranged in an axially extending groove between an inner surface of the housing and an outer surface of the main bearing. The pressed-in compression ring can create or cause an undercut, which then ensures that the main bearing is securely fastened in the housing and well-suited for high loads and forces in the axial direction.

[0015] It can be particularly advantageous to provide that at least a part or section of the groove has an axially widened shape, for example, a frustoconical shape. The corresponding chamfers or bevels on the outer surface of the main bearing and on the inner surface of the housing can be designed and dimensioned such that undercut-free insertion of the main bearing is possible, but that after pressing in the crush ring, the groove filled with the crush ring between the main bearing and the housing forms an undercut for the main bearing and thus secures the main bearing in the housing.

[0016] In an advantageous embodiment of the electromechanical brake, the compression ring may have axially extending slots distributed around its circumference, preferably originating from an axial end. These slots facilitate the advantageous radial, at least partial, widening of the compression ring during the pressing-in process.

[0017] In a further, particularly advantageous embodiment of the electromechanical brake device, the groove can be designed to have a tapered section in the axial direction at its lower end. As already indicated above, this allows the compression ring to initially advance to the bottom of the groove during pressing, followed by transverse extrusion of the compression ring's end face within the groove base and a successive thickening towards the outer side of the groove, starting from the groove base and progressing upwards. This results in a particularly effective positive fit between the inner surface of the housing and the outer surface of the main bearing.

[0018] In a further, particularly advantageous embodiment, the inner surface of the housing and / or the outer surface of the main bearing may have positive-locking contours extending essentially in the circumferential direction. Such positive-locking contours may, for example, be grooves or channels similar to a thread, which, when the compression ring is pressed in and / or upsetting, result in an improved or more stable positive-locking connection.

[0019] In a further, particularly advantageous embodiment of the electromechanical brake, it can be particularly advantageous, as already indicated above, that an outer ring of the main bearing and / or the housing is made of high-strength steel and / or cast iron, or at least comprises such material.

[0020] In a further, particularly preferred embodiment of the electromechanical brake, it can also be provided that a pressed-in compression ring is arranged in an axially extending groove between an inner surface of the ratchet wheel of the screw drive and an outer surface of a spindle of the screw drive. For this connection or fastening made by means of a compression ring, all the aforementioned embodiments and aspects are also considered disclosed and claimable, wherein the inner surface of the housing is substituted with the inner surface of the ratchet wheel and the outer surface of the spindle is substituted with the outer surface of the main bearing.

[0021] In a correspondingly advantageous way, the connection or fastening via a compression ring can then be used several times in the area of ​​the threaded drive, which makes the manufacturing processes and other related aspects, such as quality assurance measures and the like, more effective.

[0022] 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. Figure 1: shows an exemplary sequence of a process according to the invention based on different processing states; Fig. 2: shows different process stages of the process according to the invention; Fig. Figure 3 shows an enlarged section of a stage of pressing in the compression ring; Fig. Figure 4 shows an enlarged view of a fully pressed and compressed compression ring; Fig. Figure 5 shows an alternative embodiment of a compression ring; Fig. Figure 6 shows an example of the structuring of an outer surface of the main bearing. Embodiments of the invention

[0023] Identical elements or elements with the same function are marked with the same reference symbols in the figures.

[0024] Fig. Figure 1 shows, from left to right in the different process stages a to d, an exemplary process sequence of a method according to the invention for joining a main bearing and a housing of an electromechanical brake device. In process step a, the main bearing of the threaded drive of the electromechanical drive unit and the housing 02 are provided. It is already apparent that a part of the outer surface 03 of the main bearing 01 and a part of the inner surface 04 of the housing are inclined or slanted in the axial direction A.

[0025] As can be seen in process stage or process step b, the main bearing 01 is inserted into the housing 02, with opposing stop surfaces 05 and 06 coming into contact with each other. The inclined surfaces create a groove 07, which has the largest radius or circumference in a lower section adjacent to the groove base 08 and becomes narrower towards the top. A reservoir section 09 of the groove 07 is formed in an end, upper section.

[0026] In process step c, the compression ring 10, for example as a tubular element made of mild steel or aluminum, is positioned in the area of ​​the groove 07 and pressed into the groove 07. In process step d, the pressing in, and if necessary, upsetting and / or compression of the compression ring 10 is completed, thereby forming a positive fit and a positive-locking connection between the main bearing 01 and the housing 02, as well as an undercut between the main bearing 01 and the housing or compression ring 10, so that the main bearing 01 is secured in the housing 02. An upper part of the compression ring 10 is displaced in the end reservoir sections 09 of the groove 07.

[0027] In the side sectional views of the Fig. 2 are intermediate steps between process steps c and d of the Fig. 1 shown again in detail. Process step c on the left side of the Fig. 2 corresponds to process step c of the Fig. 1, in which the compression ring 10 is inserted, with the main bearing 01 already inserted into the housing 02. In process step c1, the compression ring 10 is already partially pressed into the groove 07 in the axial direction A, but has not yet reached the bottom of the groove 08. However, in process step c1, the compression ring 10 is already radially expanded in a lower section. In process step c2, due to the pressing in of the compression ring 10, a lower end of the compression ring 10 has reached the bottom of the groove 08. An upper end of the compression ring 10 still protrudes beyond the top surface 11 of the main bearing. The difference between process step c2 and process step c3 of the Fig. 2 is essentially derived from the description of the Fig. 3 visible.

[0028] The procedural step d of the Fig. 2 essentially corresponds to process step d in the Fig. 1. It can be seen again that the upper edge of the compression ring 10, which still protruded in process steps c2 and c3, was displaced into the end reservoir section 09 of the groove 07.

[0029] In the enlarged view of the Fig. Figure 3 shows that in the area of ​​the groove, the inclination of the outer surface 03 of the main bearing 01 is slightly greater than the inclination of the inner housing surface 04. As a result, in addition to having a larger radius or circumference downwards in the axial direction A, the groove 07 also has a taper within itself or with respect to the groove width, causing the groove width to increase from the groove bottom 08. This leads to the advantageous behavior described in the Fig. 3 is shown in a preliminary way, in which, after reaching the bottom of the groove 08, the compression ring 10 undergoes transverse extrusion in the bottom of the groove, which leads to a successive thickening of the compression ring 10 in the direction of the outside of the groove 12.

[0030] In the Fig. Figure 3 shows that in a lower section of the groove 07, the compression ring 10 has already thickened up to the outer surface of the groove 12, and in an upper section of the groove 07, a residual gap remains between the compression ring 10 and the outer surface of the groove 12, which, however, is successively filled from bottom to top as the compression ring 10 is pressed in and subjected to transverse extrusion. Fig. Figure 3 also shows that the end reservoir section 09 of the groove 07 is not yet covered with material of the compression ring 10.

[0031] In comparison, in the Fig. Figure 4 shows that, on the one hand, the compression ring 10 has continuously reached the outer surface of the groove 12 in the area of ​​the inner surface of the housing 04, and the previously protruding material of the compression ring 10 has been pressed or formed into the said reservoir section 09 of the groove 7.

[0032] Fig. Figure 5 shows an alternative embodiment of the compression ring 10, in which slots 16 are arranged or formed distributed around the circumference of the compression ring 10 in the axial direction A extending from an axial end of the compression ring 10, which preferably facilitate the radial expansion of the compression ring 10. For the sake of completeness, it should be mentioned that the embodiment of the compression ring 10 according to [reference to figure] is preferred. Fig. 5 would be attached to the housing 02 and the main bearing 01 in such a way that the axial end from which the slots 16 originate points towards the main bearing 01 and the housing 02.

[0033] The Fig. Figure 6 shows an example of a main bearing 01, whose outer surface 03 is provided with positive-locking contours 13, for example in the form of grooves or threads. This further improves the positive locking between the main bearing and the housing. Corresponding positive-locking contours 13 can also be formed or arranged on the inner surface 04 of the housing.

[0034] Fig. Figure 7 shows, without going into detail, another possibility for the application of the method according to the invention in the area of ​​an electromechanical braking device and its electromechanical drive unit. In the Fig.Figure 7 shows a spindle 14 of a threaded drive, preferably a ball screw drive. A ratchet wheel 15 is attached to the spindle 14. The connection between the ratchet wheel 15 and the spindle 14 can be made or implemented analogously to the connection and method described above, wherein the inner surface 04 of the housing is replaced by the inner surface of the ratchet wheel and the outer surface of the main bearing is replaced by the outer surface of the spindle 14 of the threaded drive. 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] US 6,106,156 A

[0004]

Claims

[1] Method for joining a main bearing (01) and a housing (02) of an electromechanical brake device, in particular for use in a motor vehicle, wherein the brake device has an electromechanical drive unit comprising a threaded drive, preferably a ball screw drive, mounted in the housing (02), wherein the main bearing (01) of the threaded drive is fixed in the housing (02) in an axial direction (A), characterized by , that a compression ring (10) is pressed into an axially extending groove (07) between an inner housing surface (04) and an outer surface (03) of the main bearing (01). [2] Method according to claim 1, characterized by , the compression ring (10) is radially expanded section by section during pressing, the expansion being defined and / or limited by a frustoconical groove section of the groove (07) between the inner housing surface (04) and the outer surface (03) of the main bearing (01). [3] Method according to claim 1 or 2, characterized by , that the compression ring (10) is pressed in until it reaches a groove base (08) of the groove (07). [4] Method according to claim one of the preceding claims, characterized by , that the compression ring (10) is compressed flush with a top surface (11) of the main bearing (01), whereby material of the compression ring (10) protruding beyond the top surface (11) of the main bearing (01) is displaced into a reservoir section (09) of the groove (07) at the end in the axial direction (A). [5] Electromechanical braking device, in particular for use in a motor vehicle, wherein the braking device has an electromechanical drive unit comprising a threaded drive, preferably a ball screw drive, mounted in a housing (02), wherein a main bearing (01) of the threaded drive is fixed in the housing (02) in an axial direction (A), in particular by means of a method according to one of claims 1 to 4, characterized by , that a pressed-in crush ring (10) is arranged in a groove (07) extending in the axial direction (A) between an inner housing surface (04) and an outer surface (03) of the main bearing (01). [6] Electromechanical braking device according to claim 5, characterized by , that the compression ring (10) has slots distributed over a circumference, extending in the axial direction (A), preferably originating from an axial end. [7] Electromechanical braking device according to claim 5 or 6, characterized by, that the groove (07) has a taper in the axial direction (A) in a lower end section. [8] Electromechanical braking device according to any one of claims 5 to 7, characterized by , that the inner surface (04) of the housing and / or the outer surface (03) of the main bearing (01) have positive locking contours (13) extending substantially in the circumferential direction. [9] Electromechanical braking device according to any one of claims 5 to 8, characterized by that the housing (02) and / or an outer ring of the main bearing (01) comprise or consist of high-strength steel and / or cast iron. [10] Electromechanical braking device (1) according to any one of claims 5 to 9, characterized by , that a pressed-in crush ring (10) is arranged in an axially extending groove (07) between an inner surface of a ratchet wheel and an outer surface (03) of a spindle (14) of the threaded drive.

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