GB1421777A - Fluid seals and method of making a moulding core therefor - Google Patents

Abstract

1421777 Shaft seals CHICAGO RAWHIDE MFG CO 28 Dec 1972 [29 Dec 1971 24 April 1972] 59863/72 Heading F2B A seal unit for a shaft 32a, Fig. 5, comprises a mounting portion (12), Fig. 1 (not shown), and a flexible lip portion 18a defined by at least partially axially undulating frusto-conical surfaces 24a, 28a, the included angle between the surface 24a and the shaft 32a being from about 15 to about 30 degrees, and the included angle between the surface 28a and the shaft 32 being from about 40 to about 60 degrees. The surfaces 24a, 28a define a preferably sinuous contact band 30a which co-operates with the shaft surface to exert a pumping action on oil tending to leak through the seal unit. The contact edge of the lip 18a may be generally sinusoidal, Fig. 6, of irregular wave form, Fig. 9 (not shown) of generally cycloid form, Fig. 10 (not shown), or of sawtooth form, Fig. 12 (not shown). Further, straight, circumferential edge portions may be separated by curved portions, Figs. 11 and 14 (not shown), and a wave form of varying amplitude may be employed, Fig. 13 (not shown). Also, Fig. 15 (not shown), the lip surface may be broadened to form lands (90) of varying width for co-operation with the shaft, and projections 96, Fig. 16, may be provided adjacent the lip edge to enhance the pumping action. The lip portion may be produced by moulding around a core 46, Fig. 3, the core 46 being formed by means of a cutting tool 52 which is reciprocated parallel to the core axis and tilted about an angle γ in timed relation to rotation of the core 46 in order to cut the required core profile.