Labyrinth seals

In an apparatus including bearing means permitting relative rotation between a shaft and a component of the apparatus about the axis of said shaft, said bearing means comprising an inner bearing ring, an outer bearing ring, and rolling elements between the two bearing rings, the shaft and said component defining an annular space at one side of the bearing means, a device incorporating said bearing means and providing a labyrinth seal for said annular space, said device comprising a first annular member mounted on said shaft and supporting the inner bearing ring of said bearing means, and a second annular member mounted on said component and supporting the outer bearing ring of said bearing means, said members having annular tongues which are interleaved to define a narrow annular tortuous labyrinth passageway between the members along the entire length of the labyrinth passageway, said passageway having an inner end leading to said annular space and an outer end leading to the exterior of the apparatus, at least one tongue on each member having a frusto-conical surface, at least one portion of said labyrinth passageway being defined by the frusto-conical surfaces, and said frusto-conical surfaces extending radially outwards in the direction along the passageway leading to said outer end thereof whereby any foreign matter circulating around said one portion of the passageway upon relative rotation between the members will be urged by centrifugal force towards the outer end of the passageway, said device having the improvement:

• the radially outer one of said frusto-conical surfaces forming said one portion of the labyrinth passageway is inclined relative to the axis of the shaft at a greater angle than that of the radially inner one of said frusto-conical surfaces relative to said axis, so that said inner and outer frusto-conical surfaces diverge away from one another in the direction leading to the outer end of the passageway whereby any foreign matter does not become trapped between the frusto-conical surfaces, irrespective of any slight tilting of one or both of said members.

In an apparatus including bearing means permitting relative rotation between two components of the apparatus about an axis of one of the components, said components defining an annular space accommodating said bearing means, a device for providing a labyrinth seal for said annular space comprising two annular members mounted one on each of said components, said members having annular tongues which are interleaved to define a narrow annular tortuous labyrinth passageway between the members along the entire length of the labyrinth passageway, said passageway having an inner end leading to said annular space and an outer end leading to the exterior of the apparatus, the tongues on the two members having frusto-conical surfaces which extend radially outwards in the direction along the passageway leading to the outer end thereof, and the labyrinth passageway having at least two successive annular portions each of which is formed by two of said frusto-conical surfaces, said device having the improvement:

• the radially outer one of the two frusto-conical surfaces forming each of said portions of the labyrinth passageway is inclined relative to said axis at a greater angle than that of the radially inner one of said two frusto-conical surfaces so that in each of said portions said inner and outer frusto-conical surfaces diverge away from one another in the direction leading to the outer end of the passageway.