SEALING RING OF THE COMPOSITE TYPE

Abstract: A sealing ring of the composite type comprises an O-ring (15) of an elastomer, which is disposed on the outside of a rigid support ring (16) having an outside groove.

Description: SEALING RING OF THE COMPOSITE TYPE The present invention relates to a sealing ring of tiia composite type. When an element of a machinery construction is mounted to engage another element and a through passage for conducting hydraulic fluid in a hydraulic system extends through the elements across the interface between the elements, a seal usually is provided around ' the passage in the interface between the elements by means of a sealing ring, usually a 0-ring of an elastomer, which is located in an enlargement of the passage in one element. It has been noted at several occasions that such a sealing ring may be dislocated from its position in the enlargement and may be carried away by the hydraulic fluid flowing through the passage. The reason for this seems not tρ be fully explained. However, the inventors of the present invention do not think it unlikely that the sealing ring is compressed elastically under the pressure of the hydraulic fluid in the passage and then when the pressure is relieved or substantially reduced, recoils by the inherent elasticity thereof and then simply springs out of the seat thereof in the enlargement to land in the passage and be carried away by the hydraulic fluid flowing through the passage. Said disadvantage can be overcome by slotting an annular groove for the sealing ring in the surface of one element engaging the other element, concentrically around the passage. However, such machining means a considerable increase of costs and therefore is no attractive solu¬ tion of the problem. The purpose of the invention is to solve the problem in a simple manner without structural modifica- tions of one or the other of the two elements, and this is achieved according to the invention by a sealing ring of the composite type having the characteristics appearing from claim 1. Then, it is the sealing ring of the composite type itself which is constructed such 5 that said disadvantage cannot arise. No modification of the two elements is necessary; the sealing ring of the composite type can be mounted as any other sealing ring in the conventional enlargement of the passage in one element. 10 - Sealing rings of the composite type are previously known per se and are disclosed e.g. in DE-A-1 ,750,182 and US-A-3,918,726. However, these specifications relate to specific embodiments wherein a stiffener is integrated w th an elastomer to form a unitary sealing 15 ring. According to the invention, a conventional 0-ring of an elastomer is used as a separate element in combination with the support ring. It should also be mentioned that according to FR-C-1 ,240,659 efforts ' have been made to solve the 20 problem referred to herein by providing an insert of L-shaped cross section, which is located in the enlarge¬ ment of the passage in one element with one flange engaging the bottom of the enlargement while the other flange forms a partition between the enlargement and 25 the passage, an 0-ring of an elastomer being located in the annular groove formed by the enlargement and the insert. In this manner the slotting of a groove can be dispensed with, but the solution is no good, because the insert must be adapted to the enlargement in each 30 specific case and the enlargement must be made larger so as to receive the 0-ring as well as the insert if the cross-sectional area of the 0-ring shall be as large as the cross-sectional area of " the 0-ring when this ring only is located in the enlargement. Such a modifica* 35 tion of the enlargement is not always convenient or even possible. In any case it is completely clear that such - an insert cannot always be mounted in existing machinery constructions. However, the sealing ring of the composite type according to the invention can always be 5 used quite easily. In order to explain the invention in more detail the invention will be described with reference to the accompanying drawing in which FIG. 1 is a fragmentary cross-sectional view of 10 • two machi-ne elements forming a through passage and being provided with the sealing ring of the composite type according to the invention, FIG. 2 is an enlarged cross-sectional view of the sealing ring, and 15 FIG. 3 is a plan view of the sealing ring in FIG. 2. In FIG. 1 of the drawing, two machine elements. 10 and 11 are shown which are engaged one with the other at flat surfaces and are clamped in one way or the other. 20 A passage 12 extends through the two machine elements and can form part of a hydraulic system. To seal in the interface 13 between the two elements an enlargement 14 of the passage 12 is provided in the element 10, said enlargement being open in the surface of the element 10, 25 which engages the element 11 at the interface 13. A sealing ring of the composite type according to the invention is located in the enlargement 14 and comprises a conventional 0-ring 15 of an elastomer, e.g. rubber, having circular cross-sectional shape, and a rigid 30 support ring 16 of metal or plastic material , forming an outside groove. The 0-ring is disposed on the outside of the support ring and is received by the outside groove of the support ring, which is curved according to the circular shape of the 0-ring. In other words, 35 the arrangement is similar to a wheel tyre disposed on the outside of a wheel rim. The support ring 16 has a smaller axial dimension than the 0-ring 15 in order that the 0-ring will be slightly compressed between the two machine elements 10 and 11 without this being obstructed by the support ring 16. Thus, the 0-ring 15 can be of a common standard embodiment and can be located and arranged in the same manner as such a standard ring without being obstructed by the support ring 16 which is a very simple element incre-asing the cost of the sealing ring insignificantly but preventing effectively the 0-ring 15 from leaving the enlargement 14. The 0-ring can fit loosely on the support ring but there is nothing to prevent it these two rings being permanently interconnected in one way or the other. Either the rings are interconnected or not they can be handled as a ' unit. The support ring 16 can have the. same axial length as the 0-ring 15 but in that case through apertures should be provided in the support ring between the inside and outside surfaces thereof in order that pressurized hydraulic fluid in the passage 12 can affect the 0-ring and compress said ring so as to engage sealingly the elements 10 and 11, and in order that pressurized fluid will not be trapped between the 0-ring and the support ring.

Claims: 1. Sealing ring of the composite type, c h a r a c t e r i z e d in that an 0-ring (15) of an elastomer is disposed on the outside of a rigid support ring (16) having an outside groove. 2. Sealing ring as claimed in claim 1, c h a r a c t e r i z e d in that the support ring (16) has smaller axial dimension than the 0-ring (15). 3. Sealing ring as claimed in claim 1, 10 c h a r a c t e r i z e d in that the support ring (16) forms through apertures between the inside and outside surfaces thereof. 15 i

Inventors: BORG BERTIL, LANDAEUS KJELL, BORG, BERTIL, LANDAEUS, KJELL
Applicants: BORG BERTIL, LANDAEUS KJELL, BORG, BERTIL, LANDAEUS, KJELL
Application year: 1985
Main classification: F16J15
IPC codes: F16J15