Assembly with seal

Abstract

Proposed is an assembly comprising components (25, 29) and a seal (24) clamped between them, which is adhesively bonded to one of the components by means of a permanently elastic sealing medium (28), wherein one component (25) has an axial groove, the base (30) of which the seal is adhesively bonded to by means of the sealing medium. The seal is a profile seal with a sealing back (26) and a sealing lip (27) extending from it, wherein the sealing back has a substantially flat surface which is adhesively bonded to the base of the groove by means of the sealing medium. The assembly can be a belt tensioner (1) of an auxiliary drive belt of an internal combustion engine.

Description

[0001] The invention relates to an assembly comprising components and a seal clamped between them, which is adhesively connected to one of the components by means of a permanently plastic sealing medium, wherein one component has an axial groove, to the base of which the seal is adhesively connected by means of the sealing medium.

[0002] German patent application DE 10 2020 129 439 A1 discloses an assembly comprising components and a seal clamped between them. The assembly is a belt tensioner for an auxiliary drive belt of an internal combustion engine.

[0003] A component assembly of the type mentioned above is shown in DE 18 26 021 U, DE 18 54 662 U, DE 699 735 A and US 2014 / 0 138 917 A1.

[0004] The present invention is based on the objective of improving such an assembly with regard to a robust assembly process in such a way that the positioning of the seal is carried out as designed.

[0005] The solution to this problem is achieved by the fact that the seal is a profile seal with a sealing back and a sealing lip extending from it, wherein the sealing back has a substantially flat surface which is adhesively bonded to the groove base by means of the sealing medium.

[0006] Permanently elastic sealing media are polymers with very high viscosity. These media do not chemically harden but remain in this highly viscous state. Accordingly, the invention provides for fixing the seal to one component during assembly, forming a sub-assembly, practically by means of the adhesive bonding effect of the sealing medium. This fixing prevents both mispositioning due to slippage or deformation and the loss of the seal due to falling into or out of the sub-assembly. In the fully assembled state of the component, a composite seal is then present, consisting of the actual seal and the sealing medium.

[0007] A sealing medium that proved suitable for carrying out the invention in the applicant's tests is, for example, available on the market under the product name DB 1108 from the manufacturer Drei Bond. Another permanently elastic sealing medium is the product Hylomar from the manufacturer of the same name.

[0008] Advantageous embodiments of the invention are the subject of the dependent claims.

[0009] The application of the initially formless sealing medium can be carried out, for example, as a continuous or interrupted bead, whereby the dosage must be adjusted within the limits of sufficiently high adhesion on the one hand (not too little sealant) and locally limited displacement (not too much sealant). In experimental settings, a mass ratio of 0.03 < m has proven effective. M / m D < 0.2 was identified as particularly functional; m M = mass of the sealing medium and m D = Mass of the seal.

[0010] With regard to temporary deformation, which can occur during the assembly of fully enclosed seals with comparatively low rigidity and local misalignment of the seal within the assembly, the invention is particularly advantageous when the following relationship applies to the dimensional ratio of the seal: U / B > 50; U = circumference of the seal, B = width of the seal cross-section in the circumferential plane. A simple example is a readily deformable O-ring with a large diameter and small cord thickness.

[0011] The assembly is preferably a belt tensioner for an auxiliary drive belt of an internal combustion engine.

[0012] Further features and advantageous embodiments of the invention will become apparent from the following description and from the drawings, in which the belt tensioner is shown as a representative example of an assembly according to the invention. The drawings show: Fig. 1. The belt tensioner in a perspective top view; Fig. 2. The belt tensioner in a perspective view from below; Fig. 3. The belt tensioner in perspective longitudinal section; Fig. 4 the detail X according to Fig. 3; Fig. 5 A sub-assembly of the belt tensioner consisting of a base, seal and permanently plastic sealing medium in perspective exploded view.

[0013] The one in the Fig. The belt tensioner 1, shown in Figures 1 to 3, is mounted on the belt-side front of a (starter) generator integrated into the auxiliary drive belt system. This generator serves not only as a (driven) generator for power generation but also as a (driving) motor for belt starting or boosting the internal combustion engine. The belt tensioner 1 comprises a base 2, which is mounted on the generator, and two tensioning arms 5 and 6, each equipped with tensioning rollers 3 and 4. These arms are pivotally mounted on the base 2, both relative to each other and to the generator. As a so-called pendulum tensioner, the tensioning rollers 3 and 4 pre-tension the slack side of the belt, which alternates with the tension side depending on the operating conditions.

[0014] The first clamping arm 5 and the second clamping arm 6 as well as the base 2 are closed in a ring shape and enclose the rotary axis 8 of the generator which is concentric to the pivot bearing 7 of the clamping arms 5, 6.

[0015] The belt pretension force is generated by means of a spring 9 designed here as an arc spring, which is received parallel to the belt plane in a correspondingly arc-shaped spring space within the first tension arm 5 and clamped between the tension arms 5, 6.

[0016] The swivel bearing 7 of the clamping arms 5, 6 is viewed in an extended context with Fig. 4 explained. The base 2 is a bearing flange to be bolted to the generator, with axial end faces 10 and 11 and a cylindrical collar 12. The first clamping arm 5 is radially supported against the inner surface 15 of the collar 12 by the outer surface 13 of a locking sleeve 14 and axially supported against the end face 10 by the axial end face 16 of the locking sleeve 14. The locking sleeve 14 is pressed onto a cylindrical collar 17 of the first clamping arm 5 and is thus part of the first clamping arm 5. The second clamping arm 6 is radially supported against the outer surface 19 of the collar 12 by its inner surface 18 and axially supported against the end face 11 by its end face 20. The opposing axial bearing is formed by an end face of the first clamping arm 5 (not shown here) and the end face 21 of the second clamping arm 6, which is supported against it.The sliding bearing of the first clamping arm 5 is achieved by means of a sliding lining 22 inserted between the locking sleeve 14 and the base 2. The sliding bearing of the second clamping arm 6 is achieved by means of a sliding lining 23 inserted between the second clamping arm 6, the base 2 and the first clamping arm 5.

[0017] A seal 24 arranged between the locking sleeve 14 and the base 2 protects the sliding bearing of the first clamping arm 5 from ingress of dirt and moisture. According to the present invention, the base 2, the locking sleeve 14, and the seal 24 form the assembly described in Fig.Figure 5 shows the base 2 as component 25 and the seal 24 to be fixed to it. The seal 24 is a circularly closed profile seal with a sealing back 26 and two sealing lips 27 extending from it and clamped against the locking sleeve 14. The seal 24, which is to be adhesively bonded to the base 2 during assembly using a permanently elastic sealing medium 28, is subsequently clamped between the base 2 and the locking sleeve 14 or the first clamping arm 5 as the other component 29. As mentioned at the outset, the permanently elastic sealing medium in this case is DB 1108 from the manufacturer Drei Bond, which is sprayed as a continuous circular bead onto the groove base 30 of an axial groove formed in the base 2. Due to the high viscosity of the sealing medium, it is hardly or not at all possible to apply individual drops.

[0018] The sealing surface 26 has a substantially flat surface which is adhesively bonded to the groove base 30 by means of the sealing medium 28. Alternatively, the seal 24 can be adhesively bonded to the first clamping arm 5 and, in this case, to the locking sleeve 14 by means of the sealing medium 28.

[0019] The mass m D The weight of the seal 24, made of material AEM80, is 2.7 g. Tests have shown that the mass m M For sufficiently secure adhesive fixation of the seal 24 to the base 2 made of the material AlSi9Cu3(FE), 0.1 g to 0.3 g of sealing medium is ideal. Accordingly, the mass ratio of sealing medium to seal 24 is approximately: 0.037 < m M / m D < 0.111.

[0020] The seal 24, with a mean diameter of 108.2 mm and a corresponding circumference U = 340 mm and a width B = 4.4 mm of the seal cross-section extending in its circumferential plane, has a dimensional ratio of U / B = 77 and consequently a comparatively low form stiffness, whereby the adhesive effect of the sealing medium 28 not only prevents it from falling out, but also counteracts assembly-related deformations of the seal 24.

Claims

[1] Assembly comprising components (25, 29) and a seal (24) clamped between them, which is adhesively connected to one of the components (25, 29) by means of a permanently plastic sealing medium (28), wherein one component (25) has an axial groove, with the base (30) of which the seal (24) is adhesively connected by means of the sealing medium (28), characterized by , that the seal (24) is a profile seal with a sealing back (26) and a sealing lip (27) extending from it, wherein the sealing back (26) has a substantially flat surface which is adhesively bonded to the groove base (30) by means of the sealing medium (28). [2] Assembly according to any one of the preceding claims, characterized by , that the following relationship holds for the mass ratio of sealing medium (28) to seal (24): 0.03 < m M / m D < 0.2 with: m M : Mass of the sealing medium (28) m D : Mass of the seal (24). [3] Assembly according to any one of the preceding claims, characterized by , that the seal (24) is fully closed, wherein the following relationship applies to the dimensional ratio of the seal (24): U / B > 50 with: U: Circumference of the seal (24) B: Width of the sealing cross-section in the circumferential plane. [4] Assembly according to any one of the preceding claims, characterized by , that the assembly is a belt tensioner (1) of an auxiliary drive belt of an internal combustion engine, wherein: - that one component (25) is a ring-shaped base (2) which is to be attached to the generator enclosing the axis of rotation (8) of a generator, - the other component (29) is an annular clamping arm (5) which is radially and axially mounted on the base (2) by means of a sliding lining (22), - the seal (24) is clamped between the clamping arm (5) and the base (2), - the belt tensioner (1) has a tensioning roller (3) attached to the tensioning arm (5) which applies pretension to the belt, and a spring (9) which generates the pretension force, - and the seal (24) is adhesively connected to either the base (2) or the clamping arm (5) by means of the sealing medium (28).

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