GB2231103A

GB2231103A - Bearing lubrication means

Info

Publication number: GB2231103A
Application number: GB9009265A
Authority: GB
Inventors: Michael Stuart Cropper
Original assignee: David Brown Corp Ltd
Current assignee: David Brown Corp Ltd; Clyde Union DB Ltd
Priority date: 1989-05-03
Filing date: 1990-04-25
Publication date: 1990-11-07
Anticipated expiration: 2010-04-25
Also published as: GB8910158D0; GB9009265D0; GB2231103B

Abstract

A bearing 17, 18 mounted in the end wall of a closed housing 13 and supporting a horizontal shaft 10 rotatable within the housing needs adequate lubrication. Oil 20 disposed in the housing below the level of the shaft is flung all over the interior of the housing, both tangentially and axially onto the end wall, by three pins 23 which project radially from the shaft and are equally spaced circumferentially around it. The pins are mounted in bores 22 in a collar 21 shrunk onto the shaft. A trough 24 provided on a side wall of the housing feeds oil through a passage 25 to another bearing 19. The pins also stir the oil thoroughly, and their flinging and stirring actions assist in dissipating heat from the housing. One use of this arrangement is in centrifugal pumps. <IMAGE>

Description

wearing Lubrication Means" This invention relates to bearing lubrication means1 and has for its object to improve the lubrication of a bearing mounted in the wall of a closed housing and supporting a substantially horizontal shaft rotateable within said housing.

Such lubrication has been effected hitherto by means of various kinds of oil flingers projecting from the shaft so as to travel, as the shaft rotates, through a body of oil disposed in the housing below the level of the shaft. These flingers have included a so-called oil ring comprising a circular ring of appreciably larger diameter than the shaft which loosely surrounds the shaft and engages in an annular groove in the shaft so as to hang from the shaft and dip into the oil; and a so-called oil spool which is simply an annular flange, or two annular flanges formed on a bobbin, fixed to the shaft so as to dip into the oil.

The known kinds of oil flingers suffer from the disadvantage that they fling the oil practically all tangentially. This has made it essential to provide at least one trough on the walls of the casing parallel to the shaft to catch the oil flung there and divert it to flow in the direction of the axis of the shaft so as to reach the bearing.

The present invention flings oil all over the housing, both tangentially and axially, and can thus in certain circumstances avoid the need for an oil trough within the housing, which can consequently be made smaller as well as simpler. Further advantages are that by flinging oil widely over the internal surfaces of the housing the dissipation of heat from the housing is improved, particularly where an external cooling fan is fitted; and by stirring the body of oil in the housing thoroughly the maximum cooling effect is obtained where a submerged oil cooler is fitted.

According to the invention, bearing lubrication means comprise a closed housing, a substantially horizontal shaft journalled in a bearing mounted in a wall of the housing, a body of oil disposed in the housing below the level of the shaft, and at least one pin projecting radially from the shaft so as to travel through and stir the oil as the shaft rotates and to fling oil over the interior of the housing.

A preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing which is a vertical axial section through an overhung process pump.

Referring now to the drawing, an overhung process pump includes a horizontal shaft 10 adapted to be driven at, say, 3000 revolutions per minute by an electric motor (not shown) and journalled in two bearing arrangements mounted in the opposite end walls 11 and 12 of a closed cylindrical housing 13 forming part of the pump casing 14. A-pump impeller 15 is rigidly secured on the shaft 10 in a part 16 of the casing 14 concentric with the housing 13. The bearing arrangement adjacent the impeller 15 comprises a single roller bearing 17, and that remote from the impeller 15 comprises two ball-type thrust bearings 18 and 19 so disposed side-by-side as to resist end thrusts in both directions. The ratio of the dimension of the housing 13 in the direction of the axis of the shaft 10 to its dimension perpendicular to said direction is, say, 2:3.A body of oil 20 is disposed in the housing 13 below the level of the shaft 10 for lubrication and cooling purposes.

Bearing lubrication means for the pump comprise a collar 21 shrunk onto the shaft 10 in the middle zone of the housing 13 and disposed above the oil 20 in the housing 13. The collar 21 is provided with three equally circumferentially spaced radial holes 22 into each of which there is driven the inner end of a tubular pin 23 of longitudinally split spring type. The pins 23 are thus arranged in a balanced pattern around the shaft 10 so as not to induce any vibration. The radially projecting outer ends of the pins 23 extend in turn below the surface of the body of oil in the housing 13 in order to travel through the oil 20 as the shaft 10 rotates and fling oil all over the interior of the housing 13, both tangentially and axially onto the end walls 11 and 12, and also to stir the body of oil 20 thoroughly.The amount of oil flung is maximised by the tubular pins 23 picking up oil internally and discharging it centrifugally. Sufficient oil is flung axially to lubricate the roller bearing 17 and the adjacent one 18 of the ball bearings adequately as soon as the pump is started up, but an oil-collecting trough 24 provided on a side wall of the housing 13 catches the oil flung there and feeds it through a passage 25 to the other ball bearing 19 in known manner. The action of the pins 23 in flinging oil over all the internal surfaces of the housing 13 improves the dissipation of heat from the housing 13.The pump is fitted with an external cooling fan 26 rigidly secured to the shaft 10 within a shroud 27 fixed to the housing 13, the housing 13 is provided with fins 28, and the action of the pins 23 in flinging oil 20 over all the internal surfaces of the housing 13 enhances the cooling effect of the fan 26. The pump is also fitted with a water cooling system including a finned tube 29 submerged in the body of oil 20 in the housing 13, and the action of the pins 23 in thoroughly stirring the body of oil 20 enhances the cooling effect of said system.

In a modification, the external cooling fan and/or the submerged oil cooler are/is omitted.

In another modification, the bearing assembly remote from the impeller comprises a single ball-type thrust bearing, and in these circumstances there is no need for an oil-collecting trough in the housing.

The invention is of course applicable. to mechanism other than pumps.

If the ratio of the dimension of the housing in the direction of the axis of the shaft to its dimension perpendicular to said direction is too large for a single pin or set of pins in the middle zone of the housing to fling oil axially as far as two bearing arrangements mounted in the opposite ends of the housing, two pins or sets of pins are mounted on the shaft in the respective end zones of the housing

Claims

Claims.- 1. Bearing lubrication means comprising a closed housing, a substantially horizontal shaft journalled in a bearing mounted in a wall of the housing, a body of oil disposed in the housing below the level of the shaft, and at least one pin projecting radially from the shaft so as to travel through and stir the oil as the shaft rotates and to fling oil over the interior of the housing.
2. Means according to Claim 1, wherein the or each pin is tubular.
3. Means according to Claim 2, wherein the or each pin is of longitudinally split spring type.
4. Means according to any one of the preceding claims, wherein the inner end of the or each pin is driven into a hole in a collar shrunk onto the shaft.
5. Means according to any one of the preceding claims, wherein a plurality of pins are arranged in a balanced pattern around the shaft.
6. Means according to Claim 5, wherein three pins are equally spaced circumferentially around the shaft.
7. Means according to any one of the preceding claims, wherein the shaft is journalled in two bearing arrangements mounted in opposite walls of the housing.
8. Means according to Claim 7, wherein one of the bearing arrangements comprises a roller bearing.
9. Means according to Claim 8, wherein the other bearing arrangement comprises at least one ball-type thrust bearing.
10. Bearing lubrication means constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawing.