Fastening system and hydraulic device having the same fastening system

Abstract

The invention relates to a fastening system (18) for fastening an annular body (16, 17), in particular a covering cap (8, 9), end shield or the like, which annular body comprises an annularly extending side wall (12) having an outer face and an inner face and having a collar (20) radially protruding from the outer face, to an element (4), in a particular a housing, hydraulic block (3) or the like, which element has a receiving region for the collar (20), wherein, in order to fasten the annular body (16, 17) to the element (4), the element (4) is or becomes plastically deformed such that the material of the element (4) is or becomes displaced in order to engage behind the collar (20). The element (4) comprises an annular indentation (19) having a lockable lateral outer wall (22) and a retaining contour (23) spaced radially apart from the lateral outer wall (22), and the retaining contour (23) is designed to interlockingly interact with the collar (20).

Description

[0001] Description

[0002] title

[0003] FASTENING SYSTEM AND HYDRAULIC DEVICE WITH THE SAME FASTENING SYSTEM

[0004] The invention relates to a fastening system for fastening an annular body, in particular a cover cap, bearing plate or the like, which has an annular side wall with an outer side and an inner side and with a collar projecting radially from the outer side, to an element, in particular a housing, hydraulic block or the like, which has a receiving area for the collar, wherein the element for fastening the annular body to the element is or will be plastically deformed in such a way that the material of the element is or will be displaced to engage behind the collar.

[0005] Furthermore, the invention relates to a hydraulic device, in particular a braking device for a motor vehicle, preferably a brake booster, with an element designed as a hydraulic block, which has at least one recess for forming a hydraulic chamber, and with at least one annular body designed as a cover cap and / or bearing plate, which closes the recess, wherein the annular body is fastened to the element by the fastening system described above.

[0006] State of the art

[0007] Fastening systems of the type mentioned above are known from the prior art. In hydraulic systems, such as hydraulic brake systems, hydraulic blocks are used, among other things, to conduct and distribute hydraulic media. For this purpose, for example, a bore is created in a hydraulic block, which then forms a hydraulic chamber. To close the bore or chamber, it is covered with a separate cover cap that is attached to the hydraulic block. In this case, it is known to place a cover cap on the hydraulic block and then to plastically deform the hydraulic block in such a way that the cover cap is held thereon in a form-fitting manner. To simplify this process, cover caps are known to have a radially outwardly projecting collar, which is engaged behind by the material of the hydraulic block that has been displaced or caulked by a caulking process.

[0008] Disclosure of the invention

[0009] The fastening system according to the invention with the features of claim 1 has the advantage that the integrity of the body and element is permanently ensured both during the joining process and at a later point in time. This requires only a minor modification of previously known fastening systems, which, however, can be implemented without great additional effort. The fastening system according to the invention is characterized in that the element has an annular recess with a caulkable outer side wall and with a retaining contour radially spaced from the outer side wall, wherein the retaining contour is designed to cooperate positively with the collar at least in a direction away from the outer side wall. The retaining contour ensures that when the element is caulked, the side wall of the annular body cannot deflect radially inward and thus become detached from the element.Furthermore, the retaining contour ensures that the caulking remains permanently tight and resilient even during subsequent operation of the system formed from the ring body and element. Even under the influence of external or internal forces, especially hydraulic forces, the side wall is prevented from being displaced inward and thus becoming detached from the caulking of the element.

[0010] According to a preferred embodiment of the invention, the side wall and the recess are each formed in a circular ring shape. The circular ring shape advantageously prevents incorrect assembly of the ring body and element. Furthermore, the circular ring shape ensures a favorable interaction between the element and the ring body, especially during the caulking process, as forces are evenly distributed and transmitted.

[0011] Particularly preferably, the collar ends radially spaced from the outer side wall of the recess. This ensures that during the caulking process, particularly when inserting the annular body into the recess of the element, the collar cannot be scratched or damaged on its radial outer side by the element. This ensures that the caulked material of the element forms a seal against the annular body, particularly against the collar.

[0012] According to an alternative embodiment of the invention, the collar forms a press fit with the outer side wall of the recess. This ensures secure attachment of the ring element to the element even before caulking, allowing the caulking process to be carried out safely.

[0013] Furthermore, it is preferably provided that the recess has an annular projection protruding radially from the outer side wall into the recess to form the press fit, i.e. a radial projection that extends in a web-like manner over the entire circumference of the outer side wall. The additional annular projection forms a section in the recess that serves to form the press fit, so that an axially separate section of the recess, in particular the section of the recess axially adjacent to it, ensures play during assembly, in particular radial play, as well as the collar at all times. The collar can thus be inserted into the outer side wall without contact, at least in this section.This creates a section that creates a press fit, and a section that enters the recess without damage, especially without scratches. During subsequent caulking, this latter section ensures a tight connection between the ring body elements. In this respect, the non-contact section represents the sealing section of the outer side wall.

[0014] Furthermore, it is preferably provided that the retaining contour is formed as an inner side wall of the recess opposite the outer side wall. The recess is thus formed in the form of an annular groove in the element, into which the annular body with the side wall and the collar can be axially inserted. The inner side wall ensures that the side wall of the annular body is supported during the caulking process, thus ensuring a secure connection between the annular body and the element when caulking the element.

[0015] Furthermore, it is preferably provided that the inner side wall is designed to run at least substantially parallel to the outer side wall. This allows the caulking forces on the inner side wall to be advantageously transferred to the element.

[0016] Particularly preferably, the inner side wall is designed to form a press fit with the inner side of the side wall of the annular body. During assembly, the annular body can thus first be pushed or pressed onto the inner side wall, forming a press fit. The press fit ensures pre-fixation of the annular body to the element, which, on the one hand, supports the caulking process and, on the other hand, improves the tightness of the system.

[0017] According to a preferred embodiment of the invention, the retaining contour is formed by an inclined base of the recess. In this case, the recess can be a first section of a stepped bore, which in particular also forms the hydraulic chamber, so that the recess does not have an inner side wall running parallel to the outer side wall. Due to the inclined orientation of the base, the side wall of the annular body is nevertheless provided with a contact surface during caulking, against which the side wall can be supported, particularly during caulking.

[0018] The retaining contour is particularly preferably formed by an annular groove formed in a base of the recess oriented perpendicular to the outer side wall. The collar or the side wall then preferably has an annular projection on its front side that can be inserted into the annular groove. During assembly, the side wall with the annular projection is thus pushed into the recess in such a way that the annular projection enters the annular groove and is thereby held positively on the element transversely to the insertion direction. This also improves the caulking process due to the advantageous retaining contour by means of the annular groove and the annular projection. The annular projection is preferably tooth-shaped, conical, V-shaped or U-shaped in cross-section, so that the annular projection can be inserted into the annular groove in a self-centering manner.

[0019] According to a preferred embodiment of the invention, the inner side wall has an undercut. Due to the undercut, the clear width of the recess increases in the insertion direction of the annular body. During caulking, the caulking forces acting on the annular body cause the side wall to be displaced at least partially into the undercut, whereby the annular body is also positively connected to the element in the recess on its inner side. This advantageously increases the load-bearing capacity of the system formed by the annular body and the element.

[0020] Furthermore, it is preferably provided that the collar has a radially outwardly projecting projection for forming the press fit and, axially spaced from the projection, a sealing portion, wherein the sealing portion is designed to cooperate sealingly with the caulked material of the element. As already described above with reference to the press projection of the recess, the formation of the press portion and the sealing portion ensures that the sealing portion cannot be damaged during assembly of the annular body 2, thus ensuring maximum tightness after the caulking process.

[0021] According to a preferred development of the invention, the element or the annular body has at least one elastically deformable sealing element that cooperates sealingly with the annular body or the element. For this purpose, the sealing element is arranged in particular such that, when the annular body and the element are joined, it is elastically clamped or deformed between the two in order to ensure a high sealing effect. The sealing element is preferably a sealant or a sealing ring, such as an O-ring. In particular, the sealing element extends over the entire circumference of the annular recess and / or the annular side wall of the annular body.

[0022] The hydraulic device according to the invention with the features of claim 14 is characterized by the inventive design of the fastening system. This results in the advantages already mentioned. Further advantages, preferred features, and combinations of features emerge in particular from the above-described features and from the claims.

[0023] The invention will be explained in more detail below with reference to the drawings.

[0024] Figure 1 shows an advantageous hydraulic system in a simplified longitudinal section according to a first embodiment,

[0025] Figure 2 shows a detailed view of the hydraulic system according to a second embodiment,

[0026] Figure 3 is a detailed view of a fastening system of the hydraulic system according to a third embodiment,

[0027] Figure 4 is a detailed view of a fastening system of the hydraulic system according to a fourth embodiment,

[0028] Figure 5 is a detailed view of a fastening system of the hydraulic system according to a fifth embodiment and

[0029] Figure 6 is a detailed view of a fastening system of the hydraulic system according to a sixth embodiment.

[0030] Figure 1 shows a simplified longitudinal section of an advantageous hydraulic device 1 designed as an electromechanical brake booster 2. The hydraulic device 1 has an element 4 designed as a hydraulic block 3. The hydraulic block 3, made in particular of aluminum, has a through-bore 5 in which an axially displaceable hydraulic piston 6 and an electric motor-operated spindle gear 7, through which the hydraulic piston 6 can be displaced, are mounted. Associated with the through-bore 5 are a cover cap 8 and a cover cap 9, which encloses a chamber 10 in which the hydraulic piston 6 and the spindle gear 7 are also located. The cover cap 9 is also designed in particular as a bearing shield that carries a rolling element bearing that supports the spindle gear 7.The cover cap 8 is designed as a closure cap that closes a hydraulic chamber between the cover cap 8 and the hydraulic piston 6. One or more hydraulic channels, which run through the hydraulic block 3 or the element 4, preferably open into the hydraulic chamber 11 in order to allow hydraulic medium to flow into or out of the hydraulic chamber 11 upon movement of the hydraulic piston 6.

[0031] The cover caps 8, 9 are each annular and each have an annular side wall 12 and 13, respectively. In particular, the side walls 12, 13 are circular. While the cover cap 8 has a closed bottom 14, the cover cap 9 has an opening 15 in its bottom through which a drive shaft for the spindle drive 7 can be passed. Due to the annular design of the side walls 12, 13, the cover caps 8, 9 represent annular bodies 16, 17 that are attached to the element 4.

[0032] For fastening the ring bodies 16,17 to the element 4, an advantageous fastening system 18 is provided, which is used on both cover caps 8,9.

[0033] As Figure 1 shows, element 4 or the hydraulic block 3 has an annular groove-shaped recess 19 on its outer walls, coaxial with the through-bore 5, which also extends in a circular ring. The fastening system 18 will now be explained in more detail with reference to the cover cap 8. The fastening system 18 has a collar 20 formed on the side wall 12 and projecting radially outward at the free end of the side wall 12. The recess 19 has an inner side wall 21 and an outer side wall 22, which are opposite one another and aligned essentially parallel to one another. The distance between the inner side wall 21 and the outer side wall 22, i.e., the clear width of the recess 19, corresponds at least essentially to the width of the side wall 12 in the region of the collar 20.The inner side wall 21 forms an advantageous retaining contour 23 for the side wall 12, which prevents a radial inward displacement of the side wall 12, in particular of the collar 20. In this case, the inward displacement is prevented by a positive fit.

[0034] The lower half of Figure 1 shows a pre-assembly step in which the cover cap 8 has already been axially pushed or inserted into the recess 19. Preferably, the inner side wall 21 has an outer diameter that is slightly larger than the inner diameter of the side wall 12 in the region of the collar 20, so that when the side wall 12 is pushed into the recess 19, a radially acting press fit is formed between the side wall 12 and the side wall 21. The cover cap 8 is thus pressed axially onto the inner side wall 21. This ensures that the cover cap 8 is already firmly connected to the element 4 during pre-assembly.

[0035] In a subsequent step, in which the fastening system 4 is completed, the material of the element 4 is plastically deformed from the radial outside towards the side wall 12, in particular by a caulking process, so that the material of the element 4 engages behind the collar 20 and thereby holds it axially in the recess 19 with a form-fitting fit. The deformed state of Figure 1 is shown at the top, while the still undeformed state of the element 4 is shown at the bottom. The press fit between the side wall 12 and the inner side wall 21 of the element 4 ensures that when the material of the element 4 is caulked, the cover cap 4 is securely held on the element 4 and is engaged behind by the material of the element 4. This also reliably prevents later unintentional loosening of the cover cap 8, since a radial retreat of the side wall 12 from the rear engagement is reliably prevented by the inner side wall 21.This ensures a high load-bearing capacity of the cover cap 8 on the hydraulic block 3, so that high hydraulic pressures can be generated and utilized in the hydraulic chamber 11. The same applies to the fastening system 18 on the cover cap 9, which is designed to correspond to that on the cover cap 8.

[0036] Further embodiments of the fastening system 18 will be discussed in more detail below.

[0037] Figure 2 shows an advantageous second exemplary embodiment which differs from the previous exemplary embodiments in that the collar 20 has a radial projection 24 at its lower end in the figure, i.e. close to the free, axial end face, which extends over the entire circumference of the collar 20. The radial projection 24 leaves a section on the collar 20 which is at a greater radial distance from the side outer wall 22. This section serves as the sealing section 25 of the collar 20. The radial projection ensures that when the side wall 12 with the collar 20 is inserted into the recess 19, the sealing section 25 remains at a distance from the material of the element 4 and thus cannot be damaged, for example scratched, by the latter.During the subsequent caulking process with a caulking tool 26, which is shown as an example in Figure 2, so that material of the element 4 is plastically deformed and pressed or pushed onto the sealing section 25, the sealing section 25 remains undamaged, so that a high sealing effect between the element 4 under the cover cap 8 is ensured.

[0038] Figure 2 also shows an optional sealing element 33, which acts between the side wall 12 and the element 4 in the recess 19. According to the present exemplary embodiment, the sealing element 33 is designed as a sealing ring, in particular an O-ring, which is held clamped between the inner side of the side wall 12 and the inner side wall 21. The sealing ring is arranged coaxially to the annular shape of the side wall 12 and is elastically clamped or deformed between the side wall 12 and the element 4. In particular, the side wall 12 and the element 4 have a receiving groove 34, 35, which, when the annular body 16 is assembled, lie opposite one another in the recess 19 and are each designed to partially accommodate the sealing ring, so that the sealing ring is securely held permanently between the two elements. Optionally, only the annular body 16, 17 or only the element 4 has a receiving groove for the sealing element 33.Alternatively, the sealing element 33 is arranged at a different location between the annular body 16, 17 and element 4, for example, at the bottom of the recess 19, as explained in more detail with reference to the exemplary embodiment shown in Figure 3. In principle, the sealing element 33 can be arranged and act at various locations between element 4 and the annular body 16, 17, regardless of the further design of the fastening system 18.

[0039] The embodiment of Figure 3 differs from the previous embodiments in that the outer side wall 22 also has a radial projection 27, which lies at the level of the radial projection 24 when the side wall 12 is inserted into the recess 19. The radial projection 27 increases the protection of the sealing section 25 against damage during assembly. In particular, the clear width of the recess 19 in the region of the radial projection 24 and / or the recess 27 is selected such that the collar 20 must be pressed into the recess 19 as a whole, so that a press fit is also created on the radial outer side or on the radial projection 24, which further increases the subsequent load-bearing capacity and robustness of the fastening system 18.

[0040] The sealing element 33 is also optionally provided in the exemplary embodiment of Figure 3. The positioning of the sealing element 33 at different locations is shown as an example in Figure 3. At a first location, the sealing element 33, like the sealing ring in the exemplary embodiment of Figure 2, lies between the inside of the side wall 12 and the inner side wall 21 of the recess 19. In contrast to the previous exemplary embodiment, however, the sealing element here is designed as a flat gasket or sealant that is applied to the side wall 12 or the inner side wall 21 before assembly. Alternatively, the sealing element 33 is also designed as a sealing ring or O-ring in this exemplary embodiment.According to a further embodiment, the sealing element 33 is arranged between the base 29, the recess 19, and the axial end face of the side wall 12, or in particular, is clamped and elastically deformed by the side wall 12 and the element 4 in the mounted position. At this point, too, the sealing element 33 can alternatively be designed as the previously described sealing ring, in particular an O-ring.

[0041] Figure 4 shows a further exemplary embodiment, which differs from the previous exemplary embodiment in particular in that the inner side wall 21 has an undercut 28. During the caulking process, or during the deformation of the element 4 for engaging behind the collar 20 by the aforementioned caulking tool, the side wall 12 is partially pressed radially into the undercut 28, so that the side wall 12 is positively prevented from being pulled out by the inner side wall 28. This further increases the load-bearing capacity of the cover cap 8.

[0042] Figure 5 shows a further embodiment of the fastening system 18, which differs from the previous embodiments in that the recess 19 dispenses with an inner side wall 21 running parallel to the outer side wall 22. Rather, in this embodiment, the base 29 of the recess 19, which in the previous embodiments is oriented perpendicular to the axial insertion direction of the inner side wall 21, is oriented at an angle a to the vertical in order to form the retaining contour 23 for the collar 20. The collar 20 also has an obliquely inclined underside or contact side 30, which, in the assembled state, runs at least substantially parallel to the base 29. The inclination of the base 29 is selected such that the base 29 forms an angle α with the outer side wall 22 that is less than 90°.During the caulking process with a caulking tool 26, as also shown by way of example in Figure 5, the side wall 12 is prevented from deflecting radially inwards in a form-fitting and force-fitting manner by the inclined base 29, so that it is advantageously engaged behind by the material of the element 4 or the hydraulic block 3. Figure 6 shows a further exemplary embodiment in which the fastening system 18 also manages without the inner side wall 21. According to this initial example, the collar 20 has an annular projection 31 at its end facing the base 29, which engages in an annular groove 32 in the base 29 during assembly. The retaining contour 23 is thus formed by the.

[0043] An annular groove 32 is formed in the recess 19, which engages radially with the projection 31 in a form-fitting manner. Here, too, a retreat of the side wall 12 during the caulking process is reliably prevented.

Claims

Claims 1. Fastening system (18) for fastening a ring body (16, 17), in particular a cover cap (8, 9), bearing shield or the like, which has an annular side wall (12) with an outer side and an inner side and with a collar (20) projecting radially from the outer side, to an element (4), in particular a housing, hydraulic block (3) or the like, which has a receiving area for the collar (20), wherein the element (4) is or becomes plastically deformed for fastening the ring body (16, 17) to the element (4) such that material of the element (4) is or becomes displaced to engage behind the collar (20), characterized in that the element (4) has an annular recess (19) with a crimpable outer side wall (22) and with a retaining contour (23) spaced radially apart from the outer side wall (22), and that the retaining contour (23) is designed toto interact in a form-fitting manner with the collar (20) at least in a direction pointing away from the outer side wall (22).

2. Fastening system according to claim 1, characterized in that the side wall (12) and the recess (19) are designed in an annular shape.

3. Fastening system according to one of the preceding claims, characterized in that the collar (20) ends radially spaced from the outer side wall (22) of the recess (19).

4. Fastening system according to claim 1 and 2, characterized in that the collar (20) forms an interference fit with the outer side wall (22) of the recess (19). Fastening system according to claim 4, characterized in that the recess (19) has an annular projection (27) extending radially from the outer side wall (22) into the recess (19) to form the press fit. Fastening system according to any one of the preceding claims, characterized in that the retention contour (23) is configured as an inner side wall (21) of the recess (19) opposite the outer side wall (22). Fastening system according to claim 6, characterized in that the inner side wall (21) is configured to extend at least substantially parallel to the outer side wall (22). Fastening system according to claim 6 or 7, characterized in that the inner side wall (21) is configured to form a press fit with the inner side of the side wall (12) of the ring body (16, 17).Fastening system according to one of the preceding claims, characterized in that the retention contour (23) is formed by an inclined base (29) of the recess (19). Fastening system according to one of the preceding claims, characterized in that the retention contour (23) is formed by an annular groove (32) formed in a base (29) of the recess (19) which is inclined, in particular, perpendicular to the outer side wall (22), wherein the collar (20) and / or the side wall (12) have an annular projection (31) on their end face that can be inserted into the annular groove (32). Fastening system according to one of the preceding claims, characterized in that the inner side wall (21) has an undercut (28). Fastening system according to one of the preceding claims, characterized in that the collar (20) has a radially outwardly projecting projection (24) for forming the press fit and, axially spaced from the projection (24), a sealing section (25) which is designed to interact sealingly with the crimped material of the element (4). Fastening system according to one of the preceding claims, characterized in that the element (4) or the ring body (16, 17) has at least one elastically deformable sealing element (33) which interacts sealingly with the ring body (16, 17) or the element (4).Hydraulic device (1), in particular brake device for a motor vehicle, preferably brake booster (2), with an element (4) designed as a hydraulic block (3) which has at least one recess for forming a chamber (10), and with at least one ring body (16, 17) designed as a cover cap (8, 9) and / or as a bearing shield which closes the chamber (10), wherein the ring body (16, 17) is attached to the element (4) by a fastening system (18), characterized by the design of the fastening system (18) according to one or more of claims 1 to 13.

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