Improved method for thermomechanically caulking components
The thermomechanical joining method addresses riveting challenges by using localized heating and deformation to create positive-locking connections in metallic components, enhancing efficiency and material versatility in electromechanical braking systems.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2025-12-01
- Publication Date
- 2026-06-25
Smart Images
Figure EP2025084848_25062026_PF_FP_ABST
Abstract
Description
[0001] R. 415251
[0002] - 1 -
[0003] Description
[0004] Improved methods for thermomechanical riveting of components
[0005] Technical field
[0006] The present invention relates to methods for the thermal joining of metallic components, preferably components of an electromechanical braking device.
[0007] State of the art
[0008] For metallic components, especially when joining components for electromechanical braking systems, riveting is a common joining and fastening method. This process is cost-effective and highly efficient. Its main disadvantages are the high process forces, which necessitate correspondingly complex equipment. Furthermore, the process has limitations with regard to hard or brittle materials, as well as materials that are difficult to form, such as die-cast aluminum or free-cutting steel. Work hardening from preceding processes is also detrimental to subsequent riveting. Additionally, tight component tolerances must be maintained, and there is only a small window of opportunity for successful and reliable riveting.Finally, the difficulty of filling the mold due to poor material flow behavior and elastic springback effects when unloading after forming the riveted joint is a disadvantage of mechanical methods for forming riveted joints that are well documented in the prior art.
[0009] Other methods for joining components are also known from the prior art. For example, DE 10 2016 102 846 A1 describes R. 415251.
[0010] - 2 -
[0011] A riveting process in which a plastic rivet stud is heated in various ways before riveting or forming the riveted joint to facilitate better deformation. For example, the plastic rivet stud is heated concurrently by resistance heating a metallic component on which or with which the plastic riveted joint is formed. Accordingly, the rivet stud itself is not heated directly, but rather the metallic component on which or with which the riveted joint is to be formed. The document also describes ultrasonic or laser heating of the rivet stud, which conversely acts directly on the rivet stud to heat and / or soften it.
[0012] With the known state of the art, a disadvantage is that resistance heating requires a fairly large heating area of a component, even away from the actual connection to be formed, which can lead to metallurgical transformations in the component that are problematic, especially if they occur over a large area.
[0013] Direct heating of the rivet stud, for example using ultrasound or laser radiation, has the disadvantage that the tool head or probe head, which is also intended to deform the rivet stud, is used to transfer the energy. When riveting two metallic components, this would require an extremely robust and correspondingly expensive riveting tool. This tool would need to be capable of providing sufficiently large amounts of energy for the partial melting of metal, either as a sonotrode or as a source of electromagnetic radiation, while simultaneously being robust enough to allow the subsequent riveting of the heated material and to withstand the forces involved.
[0014] Disclosure of the invention
[0015] The methods according to the invention for the thermomechanical joining of metallic components, preferably metallic components of an electromechanical braking device, enable a particularly advantageous locally very limited heating of the metallic material R. 415251
[0016] - 3 - of a component, so that the material forming and thus the riveting or formation of a positive-locking undercut between the contours or surfaces of the metallic components can be carried out easily and effectively, without placing excessive demands on the riveting tool or introducing the thermal energy into the component to be formed over a large area or in an uncontrolled manner.
[0017] A first method according to the invention for the thermomechanical joining of metallic components, preferably of a component of an electromechanical braking device, particularly for use in a motor vehicle, in which, to form an axially and / or radially acting positive locking, an edge contour of a first component is riveted against a second component adjacent to the edge contour by forming an undercut, comprises the following method steps:
[0018] - Positioning the first component and the second component in a riveting position.
[0019] - Heating the first component in the area of the edge contour by electrical resistance heating.
[0020] - Applying a riveting force to the edge contour of the first component using a riveting tool.
[0021] - Forming at least part of the heated edge contour while creating the form-fitting undercut between the first component and the second component.
[0022] According to the invention, it is provided that the heating of the edge contour takes place via a forming section of the riveting tool, for which purpose the forming section of the riveting tool is designed as an electrode punch.
[0023] The present invention recognizes that a very localized or spatially limited heating of the first component is sufficient if the first component acts as an introduction or transfer point for the heat energy generated by electrical resistance heating through the forming section of the riveting tool, which actually performs the forming in the further course of the process. This means, with R. 415251
[0024] - 4 - In other words, an electrically conductive connection is established, which is made from the riveting tool, in particular the forming section which acts as an electrode, via the first component to a second electrode electrically connected to the first component, so that the contacting of the forming section of the riveting tool on the first component can be used on the one hand to build up a riveting force, but on the other hand can also be used to introduce or generate heat energy in the edge contour by electrical resistance heating.
[0025] This achieves a very targeted heating of the edge contour, which is later to be formed, at least partially or in sections. The process can optionally include, as a first step (though this step is by no means mandatory), bringing the first component into electrically conductive contact with a second electrode or counter electrode. This second electrode allows current to flow from the electrode punch of the forming section of the riveting tool to the counter electrode through the first metallic component.
[0026] The inventive method implicitly provides that the heating of the first component can only begin, or be initiated, once a minimal riveting force is applied by means of the riveting tool. This force results from the forming section of the riveting tool being in contact with the first component in the region of the edge contour, allowing the electric current to flow. Accordingly, the claimed process steps are not to be considered as self-contained and strictly sequential process steps, but rather as interconnected process steps. This applies in particular to the heating process step, the process step of applying the riveting force, and the process step of forming.
[0027] The method according to the invention makes it particularly advantageous to produce positive-locking rivet connections using relatively small, energy-saving, and easy-to-handle presses. R. 415251
[0028] - 5 - In a further, particularly advantageous embodiment of the method, it can also be provided that the heating of the first component only begins when the riveting tool, in particular the forming section, is in electrically conductive contact with the first component. As already indicated above, the riveting tool, and in particular the part that performs the forming of the material of the edge contour, namely the forming section of the riveting tool, is intended to establish the electrical contact or the electrically conductive connection between the forming section, which acts as an electrode punch, and the first component.
[0029] In an alternative method according to the invention for the thermomechanical joining of metallic components, preferably components of an electromechanical braking device, particularly for use in a motor vehicle, the formation of an axially and / or radially acting positive fit is provided, for which an edge contour of a first component is riveted against a second component adjacent to the edge contour by forming an undercut. The alternative method comprises the following process steps:
[0030] - Positioning the first component and the second component in a riveting position.
[0031] - Heating the first component in the area of the edge contour by high-energy electromagnetic radiation, especially laser radiation.
[0032] - Applying a riveting force to the edge contour of the first component using a riveting tool.
[0033] - Forming at least part of the heated edge contour, creating a form-fitting undercut between the first component and the second component.
[0034] According to the invention, the heating of the edge contour is carried out via a separate radiation source independent of the caulking tool, whereby partial melting of the metallic first component occurs during the heating process. R. 415251
[0035] - 6 -
[0036] Like the inventive method described at the beginning, the inventive method described above offers the particular advantage that relatively low riveting forces can be used and that a particularly wide range of materials, such as brittle materials and / or hard materials, can be used as joining partners, especially as the first component.
[0037] Regarding the previously described method according to the invention, it has surprisingly been shown that the metallic edge contour of the first component can also be heated and, if necessary, partially melted very precisely using high-energy electromagnetic radiation, in particular laser radiation, so that subsequent caulking can be carried out, provided that the electromagnetic radiation is not supplied by the caulking tool itself, but by a separate and external radiation source. In this case, the caulking tool does not differ significantly in form and function from a caulking tool used for purely mechanical, cold caulking of material. However, the external radiation source heats the edge contour of the first component in a targeted and very localized manner, thus facilitating the forming process.
[0038] In an advantageous embodiment of the method, the radiation can be directed into the edge contour of the first component as a defocused laser beam or a laser beam with a high-frequency motion, in particular circular motion. This ensures that a sufficient amount of heat can be introduced into the edge contour of the first component in a targeted and localized manner and within a short time.
[0039] In a further, particularly advantageous embodiment of the method, the radiation can be directed and directed only onto the edge contour of the first component. This ensures that the first component does not experience widespread heating and undesirable metallurgical transformations, but rather that only the edge contour is heated locally. R. 415251
[0040] - 7 -
[0041] The invention also includes a method for manufacturing an electromechanical braking device comprising a thermomechanical joining of at least two metallic components of the braking device to form an axially and / or radially acting positive locking connection between the first metallic component and the second metallic component, wherein, according to the invention, the thermomechanical joining of the metallic components is carried out using a method of the embodiment of the invention described above.
[0042] Regarding the advantageous effects, reference is made to the preceding description of the joining processes. Particularly advantageous is the expansion of the range of usable materials and the creation of the possibility of forming positive-lock connections by riveting with relatively small presses.
[0043] In an advantageous embodiment of the method, it can be provided that a bearing or main bearing of the electromechanical braking device is connected as the first component and a power housing of the electromechanical braking device is connected as the second component.
[0044] 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.
[0045] Brief description of the drawings
[0046] Fig. 1a to
[0047] Fig. 1c shows different process stages of a process according to the invention in a first embodiment;
[0048] Fig. 2a to
[0049] Fig. 2b shows different process stages of a process according to the invention in an alternative embodiment. R. 415251
[0050] - 8 -
[0051] Fig. 1a shows a highly schematic representation of a first metallic component 01 and a second metallic component 02, which are to be joined together by a rivet. The second metallic component 02 is partially inserted into a recess 03 of the first component 01, for example, a cylindrical one. Along an edge contour 04 of the first component 01, material from the first component 01 is to be riveted, forming a positive-locking undercut with the second component 02 and thus securing or fixing the second component axially and / or radially relative to the first component.
[0052] For this purpose, a riveting tool 05 is already attached to the edge contour 04 of the first component 01 in a generally known manner. In the present case, at least the forming section 06 of the riveting tool 05, which is in contact with the edge contour 04, the first component 01 and a counter electrode 07 electrically connected to the first component are made of electrically conductive material, for example metal.
[0053] Figure 1b illustrates that after the riveting tool 05 is applied to the first component 01, an electric current I is applied between the riveting tool 05 and the counter electrode 07. The forming section 06 of the riveting tool 05 thus acts as an electrode punch 08. As shown in Figure 1b, increasing the riveting force F from the riveting tool 05 to the first component 01 initially results primarily in electrical resistance heating of the first component 01 in the region of the edge contour 04.
[0054] With increasing riveting force F and essentially simultaneous heating of the edge contour 04, material can be deformed from the edge contour 04, in this case radially inwards, whereby the forces required to form the rivet are many times lower than without electrical resistance heating of the edge contour 04. The state after the rivet formation is shown in Fig. 1c. It can be seen that the rivet 09 forms an undercut with respect to the second component 02, the rivet 09 being formed by deformed material from the metallic first component 01. R. 415251
[0055] - 9 - An alternative method according to the invention is shown in Fig. 2. In the example of Fig. 2a, the caulking tool 05 is not yet attached to the first component 01 and the second component 02. Instead, there is a distance between the caulking tool 05 and the first component 01 and the second component 02 that is sufficient to direct obliquely incident laser radiation 10 from a radiation source 11 onto an edge contour 04 of the first component 01 and thus heat the edge contour 04 of the first component.
[0056] Once the external radiation source 11, separate from the caulking tool 05, has sufficiently heated the edge contour of the first component via the laser radiation 10, the radiation source 11 can be switched off, and the caulking tool 05 can be applied to the first component 01 and pressed into it. This state is shown by way of example in Fig. 2b. It can be seen there that the caulking tool 05 has caused a deformation of material in the edge contour 04 heated by the laser radiation 10, which also leads to caulking and the formation of a correspondingly positive-locking undercut, thus securing or fastening the first component 01 to the second component 02 in the axial and, if applicable, radial direction.
[0057] The first component can preferably be a bearing or main bearing of an electromechanical braking system for a motor vehicle. The second component can, for example, be a power housing of an electromechanical braking system for a motor vehicle. Thus, the aforementioned components of the electromechanical braking system can be joined and connected particularly efficiently using a wide variety of available materials.
Claims
R. 415251 - 10 - Claims 1. Method for thermomechanical joining of metallic components, preferably components of an electromechanical braking device, in particular for use in a motor vehicle, wherein, in order to form an axially and / or radially acting positive locking, an edge contour (04) of a first component (01) is riveted against a second component (02) adjacent to the edge contour by forming an undercut, comprising the process steps: Positioning the first component (01) and the second component (02) in a riveting position; Heating the first component (01) in the area of the edge contour (04) by electrical resistance heating; - Applying a riveting force (F) to the edge contour (04) of the first component using a riveting tool (05); Forming of at least a part of the heated edge contour (04) to form the positive-locking undercut between the first component and the second component, characterized in that the heating of the edge contour (04) is carried out via a forming section (06) of the riveting tool (05), for which the forming section (06) of the riveting tool (05) is designed as an electrode punch (08).
2. Method according to claim 1, characterized in that the heating of the first component (01) only begins when the riveting tool (05), in particular the forming section (06), is brought into electrically conductive contact with the first component (01).
3. Method for thermomechanical joining of metallic components, preferably components of an electromechanical braking device, R. 415251 - 11 - especially for use in a motor vehicle, wherein, in order to form an axially and / or radially acting positive locking, an edge contour of a first component (01) is riveted against a second component (02) adjacent to the edge contour by forming an undercut, comprising the process steps: Positioning the first component (01) and the second component (02) in a riveting position; Heating the first component (01) in the area of the edge contour (04) by high-energy electromagnetic radiation, in particular laser radiation (10); - Applying a riveting force (F) to the edge contour of the first component (01) using a riveting tool (05); Forming of at least a part of the heated edge contour (04) to form the positive-locking undercut between the first component (01) and the second component (02), characterized in that the heating of the edge contour (04) is carried out via a separate radiation source (11) independent of the riveting tool (05), wherein a partial melting of the metallic first component takes place during the heating process.
4. Method according to claim 3, characterized in that the radiation is emitted into the edge contour as a defocused laser beam (10) or as a laser beam (10) with a high-frequency movement, in particular circular movement.
5. Method according to 3 or 4, characterized in that the radiation is emitted directly and only into the edge contour (04).
6. Method for manufacturing an electromechanical braking device, comprising a thermomechanical joining of at least two R. 415251 - 12 - metallic components (01, 02) of the brake device to form an axially and / or radially acting positive locking connection, characterized in that the thermomechanical joining of metallic components (01, 02) is carried out using a method according to one of claims 1, 2 or 3 to 5.
7. Method according to claim 6, characterized in that a bearing is connected as the first component and a power housing of an electromechanical braking device is connected as the second component.