Annular sealing disc

Abstract

The invention relates to a screw arrangement comprising a screw (16) with a thread-bearing stem and an annular sealing disc (10) for sealing a component assembly (14), wherein the sealing disc (10) has a first end face (10a) and a second end face (10b), wherein the sealing disc (10) composed of a metallic material is fastened captively between a screw head (16a) and the thread-bearing part (16b) of the stem. The invention is distinguished in that the sealing disc (10) has a peripheral recess (12) in its first end face (10a) facing away from the head (16a).

Description

[0001] Annular sealing disc

[0002] The invention relates to an annular sealing disc according to the type specified in the preamble of patent claim 1, a screw arrangement according to the type specified in the preamble of patent claim 9 and a component assembly according to the type specified in the preamble of patent claim 15.

[0003] It is well known that joints are sealed against external influences, such as water, using sealing washers. Sealing washers for sealing joints, particularly in battery boxes, against external influences are known, for example, from DE 10 2020 107 043 A1. In this case, a screw connection is sealed using a sealing washer, which also protects the connecting element from liquid ingress.

[0004] Furthermore, an annular sealing washer is known, for example, from JP S56 - 117 113 U, which has at least one groove in one of its two end faces. A circumferential rubber seal is inserted into the at least one groove. A surface of a fastening element rests against a first end face. A second, opposite end face of the washer rests against the underhead surface of a screw.

[0005] In this case, aluminum sealing discs can be used for sealing, which are more cost-effective than plastic ones. The problem is that such sealing discs often corrode in the presence of chloride ions (salt media). This impairs the function of the sealing disc, and the sealing disc must be replaced. The invention is based on the object of developing an annular sealing disc according to the type specified in the preamble of claim 1 in such a way that the corrosion resistance of the sealing disc is increased.

[0006] The problem is solved by the characterizing features of claim 1 in conjunction with its preamble features.

[0007] The subclaims form advantageous developments of the invention.

[0008] The invention is based on the finding that sealing discs which seal joints, even if contact corrosion is avoided, corrode in the area of ​​the infiltration due to liquid infiltration caused by external influences, in particular saline media.

[0009] In a component assembly comprising a connecting element, a sealing disc, and a component, a gap in the micron range forms between a wall of the component and the adjacent sealing disc, even when the assembly is sealed. A capillary effect can develop in this gap, leading to fluid infiltration, which can accumulate at the edge of the component assembly at the transition from the sealing disc to the wall of the component.

[0010] In a known manner, an annular sealing disc for sealing a fastener has an inner and an outer radius, a flat first end face, and a second end face. The inner radius is the radius of the central recess of the sealing disc and corresponds to half the inner diameter of the central recess. The outer radius is half the outer diameter of the sealing disc. The smooth first end face has a surface-related roughness value Sa of, in particular, less than 50 pm. The surface-related roughness value Sa can be defined by the arithmetic mean of the topography height z(x,y) and can be calculated using the following formula: where A is the surface under consideration and z(x,y) is the profile height. The sealing disc is made of one piece and consists exclusively of a metallic material. According to the invention, the ring width, which is formed as the difference between the outer radius and the inner radius, has a ratio of inner radius to outer radius of less than 0.5, whereby the ring width is greater than 0.5 times the outer radius (r a ). At least one completely circumferential, groove-like recess with a recess depth of more than three times the area-related roughness value Sa is introduced into the flat first end face. According to the invention, the radial distance from the outer radius of the disc to the groove-like recess is smaller than the radial distance from the inner radius to the groove-like recess. This increases the corrosion resistance of the sealing disc, at least in the area lying radially within the groove-like recess.

[0011] Preferably, a radially outer boundary surface of the recess is spaced from the inner radius of the sealing disc by more than 50% of the ring width. Preferably, a radially inner boundary surface of the recess is also spaced from the inner radius of the sealing disc by more than 50% of the ring width. The radially outer boundary surface is the outermost surface in the radial direction that has an angle of more than 45° to the first end face. Furthermore, the other outermost end face is preferably spaced from the outer radius of the sealing disc by more than 10% of the ring width.

[0012] The distance of the outer interface, and preferably also the inner interface, from the inner radius by more than 50% of the ring width ensures that sufficient residual area is available as a buffer zone to the connection point to prevent water from penetrating the inner area. To limit the capillary effect in the radial direction, the radially outer interface merges into the first end face at an angle of more than 45°, viewed in cross-section.

[0013] Preferably, the groove-like recess is circular and has an inner annular groove radius and an outer annular groove radius. The inner annular groove radius corresponds to the sum of the inner radius and the radial distance from the inner radius to the groove-like recess. The outer annular groove radius corresponds to the difference between the outer radius and the radial distance from the outer radius to the groove-like recess. This ensures easy insertion of the recess into the first end face. The outer boundary surface of the recess is formed at the outer annular groove radius, and the inner boundary surface of the recess is formed at the inner annular groove radius.

[0014] The hardness of the metallic material of the sealing disc is preferably less than 130 HB, preferably less than 100 HB. The metallic material is preferably aluminum or an aluminum alloy, in particular a wrought aluminum alloy. This provides a cost-effective material. Furthermore, in conjunction with an aluminum component, contact corrosion between the sealing disc and the component wall can be avoided.

[0015] The width of the groove-like recess is designed to be relatively small. It is preferably smaller than 1 / 4 of the ring width, in particular less than 1 / 8 of the ring width.

[0016] The first and second end faces of a substantially hollow-cylindrical sealing disc are, in particular, plane-parallel. The height of the sealing disc is preferably smaller than the inner radius.

[0017] According to a further advantageous embodiment of the invention, the ratio of the height of the sealing washer to twice the outer radius, i.e., the outer diameter, is less than or equal to 0.1. This ensures good deformability of the sealing washer when tightening the screw, thereby increasing the sealing effect.

[0018] Preferably, the first flat end face has a plurality of completely circumferential groove-like, in particular annular, concentric recesses. By incorporating a plurality of circumferential groove-like recesses, the corrosion resistance can be further increased if the area of ​​the sealing disc extending from the outer edge to the beginning of the first groove, as seen from the outside, should be damaged by corrosion to such an extent that the adjacent electrolyte can reach this groove not only by capillary action but also by direct inflow.

[0019] According to a further advantageous embodiment of the invention, both end faces each have a groove-like recess. By providing a recess on each side, the sealing disc can be mounted independently of the side. This saves time during assembly. This is particularly advantageous for automated assembly, since the orientation of the sealing disc does not need to be taken into account.

[0020] A further aspect of the invention relates to a screw assembly comprising a screw with a threaded shaft and an annular sealing washer with an inner and outer radius for sealing a component assembly. The sealing washer has a first end face and a second end face. The sealing washer is formed in one piece and exclusively from a metallic material. The sealing washer is captively secured between a screw head and the threaded part of the shaft.

[0021] According to the invention, the sealing washer has a circumferential recess in its first end face facing away from the head. The screw head has a larger outer radius than the sealing washer and preferably has a flat bearing surface.

[0022] The circumferential, groove-like recess limits the capillary effect that occurs in a component assembly between the first end face and the top of the component's wall in a radially inward direction at the radially outer boundary surface of the recess. Complete infiltration of the sealing disc beyond the groove, in a radially inward direction, is prevented.

[0023] The larger outer radius of the screw head prevents the sealing washer from becoming misaligned or jammed during automatic feeding. Furthermore, this ensures uniform surface pressure across the entire surface of the sealing washer, sealing the joint.

[0024] Preferably, the sealing washer is rolled or caulked onto the screw. This ensures a simple, captive arrangement of the sealing washer on the screw. This enables quick, automatic assembly of the screw assembly with a single component.

[0025] According to a further advantageous embodiment of the invention, the inner radius of the sealing washer on the second end face is larger than the inner radius on the first end face. As a result, the radial distance between the sealing washer and the shaft of the screw is small, so that radial play of the sealing washer is kept to a minimum. Furthermore, the smaller inner radius on the first end face forms an undercut for the thread of the screw, so that the sealing washer is limited in the axial direction along a screw axis by the undercut on the one hand and by the screw head on the other. This embodiment can be achieved by caulking the sealing washer.

[0026] The screw is preferably designed as a self-tapping or metric screw. This allows the screw to be tightly screwed into a female thread or a screw bushing. According to a further advantageous embodiment of the invention, the screw is designed as a flow-hole-forming screw. This enables connection to a non-pretreated fastening area.

[0027] Preferably, the annular sealing disc of the screw arrangement is designed as the annular sealing disc according to the invention as described above.

[0028] The screw can, for example, be made of steel and have a corrosion-protection coating, in particular a zinc-nickel coating or zinc flake coating, with the sealing washer preferably made of aluminum or an aluminum alloy. Thus, with conventional screws, the sealing washer can be made to match the material of the component.

[0029] A further aspect of the invention relates to a component assembly comprising a connecting arrangement and a component. The connecting arrangement has a connecting element with a completely circumferential pressure surface, in particular an under-head surface, and a sealing disc. The component has at least one wall. The sealing disc is pressed against the wall of the component by the pressure surface of the connecting element, wherein the connecting element penetrates the sealing disc and the wall of the component. The sealing disc has a first flat, smooth end face and a second end face. The pressure surface bears against the second end face, wherein the sealing disc forms a contact surface (sealing surface) with the wall of the component. The contact surface results from the overlap of the first end face of the sealing disc and a surface of the wall facing the sealing disc.The component in particular has a fastening area with which the connecting element interacts, forming a counter-bearing and allowing the sealing washer to be pressed against the wall of the component. For example, the connecting element can be designed as a screw and the fastening area as a hole with an internal thread. Due to the interaction of the connecting element with the fastening area, the connecting element presses the sealing washer against the wall of the component in the area of ​​the pressing surface and forms the contact surface. The surface of the wall facing the sealing washer and the first end face of the sealing washer have such a roughness in the area of ​​the contact surface that, in the connected state, a capillary effect can arise between the first end face of the sealing washer and the surface of the wall facing the sealing washer. According to the invention, the first end face of the sealing washer has a circumferential groove-like recess.The contact surface of the connecting element is larger than the disc diameter of the sealing disc. The circumferential recess limits the capillary effect at the radially outer boundary surface of the recess in a radially inward direction. This prevents fluid collected on the wall at the edge of the component assembly from infiltrating the sealing disc beyond the groove-like recess. This would lead to corrosion of the entire sealing disc. Furthermore, it prevents fluid from penetrating through the wall at the connection point into the interior of the component. The larger contact surface of the connecting element than the disc diameter ensures uniform surface pressure between the connecting element and the sealing disc.

[0030] The wall is preferably made of aluminum or an aluminum alloy. The light and strong construction of the material allows for recesses with a small cross-section.

[0031] Preferably, the component assembly comprises an annular sealing disc according to the invention as described above.

[0032] Preferably, the connecting arrangement is designed as a screw arrangement according to the invention as described above with a captively held sealing washer.

[0033] Further advantages, features and possible applications of the present invention will become apparent from the following description in conjunction with the embodiments shown in the drawings.

[0034] Fig. 1 is a sectional view of a component assembly according to the invention;

[0035] Fig. 2 is a detailed view of the component assembly according to the invention according to Fig. 1;

[0036] Fig. 3 is a bottom view of an annular sealing disc according to the invention, and

[0037] Fig. 4 is a sectional view of the screw assembly according to the invention with a sealing washer having different inner radii. Figs. 1 to 4 each show a sealing washer 10 with a first end face 10a, a second end face 10b, a groove 12, an inner radius n, and an outer radius r. a and a centric feedthrough 22.

[0038] The first end face 10a has a surface-related roughness value Sa of less than or equal to 50 μm. The depth T of the groove 12 is greater than three times the surface-related roughness value Sa.

[0039] Fig. 1 shows a sectional view of a component assembly 14. The component assembly 14 comprises the sealing washer 10, a screw 16 with a head 16a and a thread 16b, a wall 18a of a component 18, and a fastening region 20 of the component 18. The component 18 can be formed in several parts, for example from a housing base body and a cover, wherein the wall to be sealed is formed by the cover and the fastening region is formed by the housing base body to which the cover is fastened.

[0040] The wall 18a of component 18 is made of aluminum or an aluminum alloy. The sealing disc 10 is also made of aluminum or an aluminum alloy.

[0041] The sealing washer 10 is arranged between the underside of the head 16c of the screw 16 and the upper side of the wall 18a of the component 18.

[0042] The circumferential groove 12 is oriented towards the top of the wall 18a.

[0043] The groove 12 has a rectangular cross-sectional area. Other cross-sectional areas, particularly semicircular, are also conceivable.

[0044] The screw 16 passes through the sealing washer 10 and the wall 18a of the component 18 and extends into the interior 18b of the component 18. At the end of the screw 16 facing away from the head 16a, the component 18 has a fastening area 20, wherein by tightening the screw in the fastening area 20 the sealing washer 10 is pressed onto the wall 18a of the component.

[0045] The thread 16b of the screw 16 is designed as a self-tapping thread. The fastening area 20 of the component 18 can be designed as a hole. A screw 16 with a metric thread is also conceivable. In this case, a nut thread is introduced into the fastening area 20. A flow-hole-forming screw is also conceivable. In this case, the fastening area 20 could be designed as a plate-shaped part of the component 18, through which the screw penetrates, forming a hole.

[0046] The outer radius r a The sealing disc 10 is smaller than the outer radius Dk / 2 of the head 16a. The groove 12 is located in the radially outer area of ​​the sealing disc 10.

[0047] In the edge region between the second end face 10b and the upper side of the wall 18a of the component 18, liquid 24 has accumulated, such as water or the like.

[0048] The sealing washer 10 is rolled or caulked onto the screw 16 before being inserted into the component 18. The inner diameter (2 * n) of the sealing washer 10 is smaller than the thread diameter DG.

[0049] It is also conceivable that the sealing washer 10 and the screw 16 are designed to be separable and the corresponding arrangement is only carried out during the connection process.

[0050] The component 18 is designed in particular as a battery box, wherein the wall 18a of the component can be part of a cover and the fastening area 20 can be part of a battery base housing.

[0051] Fig. 2 shows a detailed view, detail X, of an edge region of the component assembly 14 according to Fig. 1.

[0052] The screw 16 presses the sealing washer 10 onto the wall 18a of the component 18 in the component assembly 14 by forming a contact surface 16c on the underside of the head 16a. Furthermore, the roughness of the underside of the head 16a forms a narrow gap in the micrometer range between the second end face 10b.

[0053] Between the first end face 10a and the top side of the wall 18a, due to the roughness of the surfaces of the first end face 10a and the roughness of the top side of the wall 18a of the component 18, even though the sealing disc 10 is pressed against the top side of the first wall, there is a distance in the pm range in some areas between the sealing disc 10 and the wall 18a. This distance is shown as an example as a gap 17. The gap 17 has a height of at most 70 pm. A capillary effect can arise between the first end face 10a and the top side of the wall 18a. Due to the capillary effect, liquid 24 which wets the top side of the wall 18a can infiltrate the sealing disc 10. As a result, so-called crevice corrosion can arise between the first end face 10a and the wall 18a, despite the similarity of the materials between the wall and the sealing disc.

[0054] The groove 12 formed in the first end face 10a limits the capillary effect by the gradient, here 90°, of an outer boundary 12a of the groove 12. Therefore, fluid can only penetrate the sealing disc 10 to the outer boundary 12a through the capillary effect.

[0055] The angle that the outer boundary of the groove 12 forms with the first end face 10a of the sealing disc 10 in cross section is greater than 45°.

[0056] Fig. 3 shows a bottom view of the sealing disc 10. The sealing disc 10 has an annular shape with the inner radius n and the outer radius r a Between inner radius n and outer radius r a The groove 12 is formed in the sealing disc 10. The groove 12 has an outer boundary 12a and an inner boundary 12b. The outer boundary 12a has a radius r nfrom the center of the sealing disc 10. The radial distance between the outer boundary 12a and the inner boundary 12b is uniformly formed all the way around. The radial distance between the inner boundary 12b and the outer boundary 12a is much smaller than 50% of the ring width b.

[0057] At least the outer boundary 12a is spaced from the inner radius n by at least 50% of the ring width b.

[0058] This means that the outer ring groove radius r n : r n n + 0.5(r a - n)

[0059] Preferably, this also applies to the inner boundary 12b and the associated inner ring groove radius r m : r m > n + 0.5(r a - n)

[0060] If the sealing disc has different inner radii along its height, the minimum inner radius ri_min is decisive. The outer annular groove radius r n is of course always larger than the inner ring groove radius rm As a result, the groove 12 lies completely in the outer area of ​​the sealing disc 10. The further out the groove 12 is located, the larger the tolerances can be, which ensure that the groove 12 does not overlap with the pre-hole of the component.

[0061] By introducing a groove 12 into the first end face 10a of the sealing disc 10, the capillary effect at the radially outer boundary 12a of the groove 12 is limited radially inward. Liquid 24, which wets the outer side of the wall 18a of the component 8 in the area of ​​the component assembly 14, infiltrates the sealing disc 10 only up to the outer boundary 12a of the groove 12. The sealing disc 10 corrodes essentially only in the area of ​​the outer radius r a in radial direction inwards to the outer boundary 12 of the groove, up to the radius r nThe groove 12 relieves capillary pressure, preventing further infiltration in the radial direction. This increases the corrosion resistance of the sealing disc 10 radially within the groove 12. This prevents the penetration of fluid 24 into the interior space 18b of the component 18 over an extended period of time.

[0062] Fig. 4 shows a sectional view of a further embodiment of a screw arrangement according to the invention, which comprises a screw 16 with a flow-hole-forming tip and a sealing washer 10. The sealing washer 10 has different inner radii n. The inner radius n, min on the first end face 10a of the sealing washer 10 is smaller than the inner radius n, max on the second end face 10b of the sealing washer 10. At the first end face 10b, the distance between the shaft 16d of the screw 16 and the sealing washer 10 is small, so that only a small radial play of the sealing washer 10 is possible. Furthermore, the sealing washer 10 forms an undercut on the first end face 10a to the thread 16b of the screw 16 or a bead formed on the screw 16, where n, min < DG / 2. Since n.max is preferably greater than DG / 2, the sealing washer 10 can be securely connected to the screw in a process step downstream of the screw production.This results in greater flexibility in the material combination of screw and sealing washer.

Claims

P atentansp ü che Annular sealing disc (10) with an inner and an outer radius (n, r a ) and a height (h) for sealing a component assembly (14), comprising a flat, smooth first end face (10a) with a surface-related roughness value Sa and a second end face (10b), wherein the sealing disc (10) is in one piece and consists exclusively of metallic material, wherein the ring width (b) is greater than 0.5 times the outer radius (r a ) and at least one completely circumferential groove-like recess (12) with a recess depth of more than three times the area-related roughness value Sa is introduced into the planar first end face (10a), wherein at the first end face (10a) the radial distance from the outer radius (r a) to the groove-like recess is smaller than the radial distance from the inner radius (n) to the groove-like recess (12). Annular sealing disc according to claim 1, characterized in that the ratio of the height (h) of the sealing disc (10) to twice the outer radius (r a ) of the sealing disc (10) is less than or equal to 0.

1. Annular sealing disc according to one of the preceding claims, characterized in that the metallic material has a hardness of less than 130 HB, preferably less than 100 HB. Annular sealing disc according to one of the preceding claims, characterized in that the metallic material is aluminium or an aluminium alloy, in particular a wrought aluminium alloy. Annular sealing disc according to one of the preceding claims, characterized in that the first planar end face (10a) has several completely circumferential groove-like, in particular annular and concentric, recesses (12). Annular sealing disc according to one of the preceding claims, characterized in that the width of the groove-like recess (12) is smaller than % of the ring width (b). Annular sealing disc according to one of the preceding claims, characterized in that an outer edge point of the cross-sectional area of ​​the recess (12) is spaced from the inner radius (n) by a distance of more than half the ring width (b) of the sealing disc (10), wherein the outer edge point is the outermost point in the radial direction which has an angle of more than 45° to the first end face (10a). Annular sealing disc according to one of the preceding claims, characterized in that both end faces (10a, 10b) each have a recess (12).A screw arrangement comprising a screw (16) with a threaded shaft and an annular sealing washer (10) for sealing a component assembly (14), wherein the sealing washer (10) has a first end face (10a) and a second end face (10b), wherein the sealing washer (10) is in one piece and is made exclusively of a metallic material and is captively fastened between a screw head (16a) and the threaded part (16b) of the shaft, characterized in that the sealing washer (10) has a circumferential recess (12) in its first end face (10a) facing away from the head (16a), wherein the screw head (16a) has a larger outer radius than the sealing washer (10). Screw arrangement according to claim 9, characterized in that the sealing washer (10) is rolled or caulked onto the screw (16). Screw arrangement according to claim 10, characterized in that the inner radius (n.max) of the sealing disc (10) on the second end face (10b) is greater than the inner radius (n.min) on the first end face (10a). A screw arrangement according to one of claims 9 to 11, characterized in that the screw (16) is designed as a flow-hole-forming screw. A screw arrangement according to one of claims 9 to 12, characterized in that the screw (16) is designed as a thread-forming or metric screw. A screw arrangement according to one of claims 9 to 13, characterized in that the annular sealing washer (10) is designed according to one of the preceding claims 1 to 8. A component assembly (14) comprising a connecting arrangement and a component (18), wherein the connecting arrangement has a connecting element with a completely circumferential pressure surface (16c), in particular a lower head surface, and an annular sealing washer (10), a component (18) having at least one wall (18a), and a sealing washer (10) with a first flat end face (10a) and a second end face (10b),wherein the connecting element passes through the sealing disc (10) and the wall (18a) of the component (18), and the sealing disc (10) is pressed against the component (18) by the pressing surface (16c) of the connecting element, wherein the pressing surface (16c) lies flat against the second end face (10b), wherein the sealing disc (10) forms a contact surface (sealing surface) with the wall (18a) of the component (18), wherein the contact surface is produced by the overlap of a first end face (10a) of the sealing disc (10) and a surface of the wall (18a) facing the sealing disc (10), wherein the surface of the wall (18a) facing the sealing disc (10) and the one first end face (10a) of the sealing disc (10) have a roughness in the region of the contact surface such that in the connected state between the first end face (18a) of the sealing disc (10) and the surface of the wall (18a) facing the sealing disc (10) can result in a capillary effect,characterized in that the first end face (10a) of the sealing disc (10) has a circumferential groove-like recess (12), and wherein the contact surface (16c) of the connecting element is larger than the outer diameter of the sealing disc (10). Component assembly according to claim 15, characterized in that the wall (18a) is formed from aluminum or an aluminum alloy. Component assembly according to one of claims 15 or 16, characterized in that the sealing washer (10) is designed according to one of claims 1 to 8. Component assembly according to one of claims 15 to 17, characterized in that the connecting arrangement is designed as a screw arrangement with a screw (16), comprising a thread (16b) and a head (16a), and a sealing washer (10) according to one of claims 1 to 8. Component assembly according to one of claims 15 to 18, characterized in that the connecting arrangement is designed as a screw arrangement according to one of claims 9 to 14.

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