SHOCK ABSORBER SEALING DEVICE.

Description

DESCRIPTION of the Industrial Utility Model from Title: "Sealing device for shock absorbers" By: RFT SpA, Italian nationality, scovado, 1 - 10121 Turin. Designated Inventor: RESTIVO Riccardo. ? t, Filed on December 17, 2003. Via Arcive- -003U 00019 DESCRIPTION The present invention refers to a sealing device for shock absorbers of the type defined in the preamble of claim 1. Sealing devices of the type illustrated schematically in Figure 1 of the attached drawings are currently known. With reference to Figure 1, a traditional sealing device comprises a rubber body 10 of an overall annular shape and with a section shaped to identify different parts capable of performing different functions. The rubber body 10 forms in its central area an external circumferential groove of generally rectangular section 11 into which an annular metal insert 20 is partially inserted which serves as a static support to withstand the axial loads to which the sealing device is subjected during its operation. On the axially lower side with respect to the metal insert, co 20, the rubber body 10 forms a conical dust lip 12 protruding in a radially inward direction. On the opposite or axially upper side with respect to the metal insert 20, the body 10 forms three coaxial lips 13, 14, 15, including a radially outer static sealing lip 13, an optional intermediate lip 14, and a radially inner oil lip 15 which is clamped in a radially inward direction by a circumferential spring 17 positioned in a groove 16 formed in a radially outer surface of the oil lip 15 to ensure the sliding contact pressure of this lip against the rod of a shock absorber (not shown). The purpose of the present invention is to create an improved sealing device for shock absorbers which allows the elimination of the traditional circumferential spring mentioned above and therefore reduces the costs for the production of the spring and the times related to its assembly on the sealing device. Another object of the invention is to create a sealing device capable of ensuring correct behaviour of the sealing lips of the device, and in particular to ensure that this they exert correct contact pressure against the stem on which the sealing device is mounted. These objects are achieved, in accordance with the present invention, by a sealing device having the characteristics defined in the appended claims. The structural and functional characteristics of a preferred but non-limiting embodiment of a device according to the invention will now be described; reference is made to the attached drawings, in which identical reference numerals designate identical or corresponding parts in the various figures. In the drawings: Figure 1 is a partial axial sectional view of a conventional sealing device; Figure 2 is a partial axial sectional view of a sealing device according to the invention in an undeformed condition; and Figure 3 is a partial axial sectional view of the device of Figure 2 applied to the stem of a shock absorber. Referring now to figure 2, a sealing device according to the invention differs from the traditional one illustrated in figure 1 essentially due to the absence of the traditional circumferential spring and the new functional shape of the oil seal lip 15. In short, the sealing device still comprises a rubber body 10 of an overall annular shape with various contours, with an annular metal insert 20 of approximately rectangular cross-section partially housed in a rectangular groove 11 formed in a median position in the external surface of the body 10. The body 10 also forms a traditional conical dust lip 12 on one side of the groove 11 and three coaxial lips 13, 14, 15 on the opposite side. The static sealing lip 13 and the intermediate lip 14, which is optional, are unchanged compared to the traditional solution. The internal oil seal lip 15 forms a root portion or proximal portion 15a with hinge functions to allow elastic flexion of the lip, and a protruding portion or distal portion 15b which is thickened in the radial or transverse direction. In this context, terms and expressions indicating positions and orientations such as "axial" and "radial" or "transverse" are intended to refer to the central geometric axis x (figure 1) of the device, coinciding with the central longitudinal axis of the shock absorber on which the device is to be applied. The thickened distal portion 15b has a conventional right-angled primary sliding contact formation 15c on the radially internal side and a secondary sliding contact formation 15d. The experiences conducted by the Applicant demonstrate that excellent results in terms of contact pressures and correct positioning of the lip 15 on the shock absorber stem can be obtained if, compared to the hinge portion or proximal portion 15a, the thickening of the distal portion 15b is approximately 0.5 mm (approximately 50%). Figure 3 schematically illustrates the shape of the rubber body 10 in an operating condition applied to the stem A of a shock absorber.

Claims

CLAIMS 1. Sealing device for shock absorbers, of the type comprising a body (10) of rubber or elastomeric material of an overall annular shape forming an external circumferential seat (11) to partially accommodate an annular metal reinforcement insert (20), a conical dust lip (12) protruding in a radially internal direction from a first side of the seat (11), at least two essentially coaxial lips (13, 15), arranged on a second side opposite to the first side with respect to the seat (11), and comprising a radially external static sealing lip (13), and a radially internal oil seal lip (15) which has at least one surface (15c, 15d) suitable for elastically and slidingly contacting the stem (A) of a shock absorber, characterised in that the internal oil-retaining lip (15) forms a proximal or root portion (15a) with hinge functions to allow elastic flexion of the lip (15), and a distal portion (15b) thickened radially with respect to the proximal portion and having said at least one surface (15c, 15d) capable of sliding contact with the stem (A) of a shock absorber, and which the oil seal lip (15) is not associated with any further elastic element capable of tightening the lip (15) in a radially internal direction against a shock absorber rod (A).

2. Sealing device according to claim 1, characterised in that the distal portion (15b) is radially thickened by approximately 50% ri respect to the proximal portion (15a).

3. Sealing device according to claim 1, characterized by the fact that the distal portion (15b) is radially thickened to a maximum of approximately 0.5 mm compared to the proximal portion (15a).

4. Sealing device according to claim 1, characterised in that it further comprises a further lip (14), intermediate between the external static sealing lip (13) and the internal oil seal lip (15), and essentially coaxial with these. wera of commerce toUSTHA CRAFTS AND AG0COUUM