GB1217043A - Bearing combination comprising a spiral groove bearing and a rolling bearing - Google Patents

Abstract

1,217,043. Hydrodynamic and rolling bearing combination. SVENSKA KULLAGERFABRIKEN A.B. 2 April, 1968 [4 April, 1967], No. 15808/68. Heading F2A. A bearing comprises a spiral groove fluid bearing and a rolling bearing mounted so that each can take thrust, in which the distribution of thrust between the two bearings is determined by the pressure in the lubricant of the fluid bearing. In Fig. 1, a shaft 3 is supported by a ball bearing 5 and a spiral groove bearing composed of two flat bearing members, 1 and 2. The member 2 is mounted in a bearing housing 6 and has a pattern of shallow spiral grooves 11 (Fig. 2, not shown) extending from the outer periphery of the member to an opening 12 at its centre. Member 2 is axially displaceable in the housing 6 to an extent limited by the screw 8. When the shaft is at rest the entire thrust load will be borne by the ball bearing 5 with the lower member of the spiral groove bearing held in light contact with the upper member by the spring 13. On rotation of the shaft lubricant is pumped through the grooves 11 from chamber 15 to chamber 12. The lubricant continues through opening 10 to chamber 14, and also through passages 16, 17 and 18 and hole 21 to the chamber 15. When the speed of rotation of the shaft reaches a given value, the centrifugal force on the piston 20 will overcome action of the spring 19, and the piston will be thrown outwards, thereby preventing the passage of lubricant through the hole 21. Lubricant will then be forced from the chamber 12 to chamber 14 causing member 2 and also the shaft to rise to the extent limited by the screw 8. Lubricant is prevented from leaking out of the chamber 14 by an 0-ring 4. When the shaft rises the outer race of the ball bearing is shifted a corresponding amount in the housing. When the speed of the shaft drops so that the centrifugal forces on the piston are no longer sufficient to keep hole 21 closed, lubricant passes from chamber 14 via hole 10 and chamber 12 back to chamber 15, and the bearings resume their starting positions. In Fig. 3 is illustrated an assembly in which the shaft is guided radially by means of a roller bearing 23 which permit axial displacement of the shaft, and the initial thrust forces are borne by ball bearings 22. When the shaft is raised in the manner described above the inner race ring 24 is lifted out of contact with the balls. In Fig. 4 (not shown), the initial thrust is borne by a roller bearing adapted to accept thrust. Fig. 8 (not shown) illustrates an embodiment in which the spiral grooves are provided on both sides of a member attached to the rotating shaft, thereby allowing the bearing to function when rotating in either direction.