GB2382385A

GB2382385A - Lubrication system for use with bearings and a method of automatically lubricating bearings

Info

Publication number: GB2382385A
Application number: GB0128171A
Authority: GB
Inventors: Charles Roderick Reed
Original assignee: NSK European Technology Co Ltd
Current assignee: NSK European Technology Co Ltd
Priority date: 2001-11-23
Filing date: 2001-11-23
Publication date: 2003-05-28
Anticipated expiration: 2021-11-23
Also published as: GB2382385B; GB0128171D0

Abstract

A rolling element bearing has inner and outer rings 11, 12 and rolling elements 13 therebetween. Alongside the bearing is a lubrication system 15 with sets of nozzles 16 which discharge discrete sprays of lubrication into the interior of the bearing. The nozzles 16 receive the lubricant from a source and employ energization devices such as piezo-electric devices, micro-valves or thermal devices which react to electrical signals to discharge and propel the lubricant.

Description

Lubrication systemfor use with bearings and a method of automatically lubricating bearings The present invention relates in general to bearings particularly but not solely rolling-element bearings and to a lubrication system for automatically controlling the supply of lubricant to such bearings.

It is known to use an air jet which emits air carrying droplets of oil into a bearing. Such air jets are not subjected to any form of control and are prone to create noise as rolling elements and a cage intersect the air jet.

An object of the present invention is to provide an improved form of lubrication for bearings.

In one aspect the invention provides a lubrication system for use with a bearing, said system including a plurality of lubricant spray nozzles provided with switching means to enable the individual nozzles to emit a spray of lubricant into the bearing. Where the bearing is a rotary bearing the nozzles are conveniently carried by a ring or some other mounting structure and disposed around a circular or part circular path alongside the bearing. The switching means responds to electrical control signals provided by a controller so that the individual nozzles can be actuated selectively in a timed sequence to emit sprays of lubricant. Conveniently, a set of nozzles can be carried on a mounting unit and several such units would be spaced apart around the circular path.

In another aspect the invention provides a method of automatically lubricating a bearing; said method comprising selectively actuating one or more lubricant spray nozzles in succession with the aid of controllable switching means as the bearing is operating. The individual spray nozzles can have different orientations so that the emitted lubricant spray can be directionally controlled as well. The nozzles would only emit liquid lubricant without admixing of air.

A lubrication system in accordance with the invention enables fine control of the position direction and the quantity of lubricant supplied thus avoiding undue wastage. The system can be operated so little noise is created. Where the bearing is a rolling-element rotary bearing lubricant can be emitted by the nozzles to ensure that sprays of lubricant are dispensed between adjacent pairs of rolling elements. The fine control afforded by the invention makes the invention particularly useful with bearings used for precision machine tools. The controller can be adapted to respond to computer generated control functions and also to a sensor or sensor arrangement which monitors parameters such as rotary speed, rotary speed and position of the bearing or temperature or loading. In this way the quantity of lubrication can be varied continuously or incrementally.

Normally the spray nozzles would be supplied with lubricant from a common supply source but it is possible to provide a number of sources with lubricants having different characteristics e. g. viscosity so that the appropriate lubricant can be dispensed according to the operating conditions.

The switching means associated with the nozzles may take the form of a number of proprietary devices used in other fields such as piezo-electric or thermal devices as used for ink-jet printers.

The control signals provided by the controller can be simple on-off pulses or more sophisticated digitally coded signals. In the latter case it is possible to control the switching means so that a group of the nozzles co-operate to emit a lubricant spray of different quantity, different velocity or in a variable time pattern.

The controller can be itself controlled by a computer program to sub-divide the nozzles into operating groups dependent on the operating condition to achieve some of these effects.

The invention may be understood more readily and various other aspects and features of the invention may become apparent from consideration of the following description.

Embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings, wherein: Figure I is a schematic cross-sectional view of part of a rolling-element bearing incorporating a lubrication system constructed in accordance with the invention; Figure 2 is a schematic end view of part of the bearing shown in Figure I and depicting the position of one of the lubrication units of the system.

Figure 3 is a diagrammatic end view of some of the rolling-elements of the bearing depicting how the lubrication nozzles of the lubrication system can be selectively activated;

Figure 4 is a schematic cross-sectional view of the bearing fitted on a shaft and showing all the main components of another lubrication system constructed in accordance with the invention and Figure 5 is a view corresponding to Figure 4 and showing a pair of bearings fitted on a shaft and a modified form of the lubrication system.

As shown in Figures 1 and 2, a rolling-element bearing 10, here in the form of an angular contact ball bearing, is composed of an inner ring 11, an outer ring 12 and a series of balls 13 engaging in tracks 14 in the inner confronting surfaces of the rings 11, 12. The balls 13 are spaced apart with a cage 9. In accordance with the invention the bearing 10 is operably associated with a lubrication supply system 15. The system 15 employs sets of individual nozzles or jets 16 which serve to dispense liquid lubricant as a spray directly into the inner zone of the bearing 10. Each set of nozzles 16 are arranged side-by-side on a mounting unit 17 and the mounting units 17 are spaced-apart around a circular path matching the curvature of the rings 11, 12. The units 17 are conveniently carried by a support ring 18 fitted on the inner ring 11 which is intended to remain stationary. The spray nozzles 16 are individually controlled by electrical signals in a manner such that a control signal is delivered to each nozzle 16 to cause the nozzle 16 to emit a spray solely of pure lubricant. The nozzles 16 have switching or enabling means which responds to the electrical control signal. The switching means can take a variety of forms. For example, the switching means can be piezo-electric devices or thermal devices or microvalves. Devices employed in ink-jet printers can be used to enable the spray nozzles to be operated selectively.

Figure 3 illustrates how the nozzles 16 can be selectively operated in zones I, II, III etc. spaced to 6 correspond to the pitch of the balls 13 as they progress in the direction of arrows P. The nozzles 16 can thus be switched on and off to only emit lubricant between adjacent pairs of balls 13.

Both Figures 4 and 5 show the other components of the lubrication supply system namely a supply 20 of lubricant linked with conduits 2 I to the nozzles 16. Normally the supply 20 would take the form of a reservoir and a pump to pressurize the lubricant for flowing through the conduits 21. The electrical control signals for the switching means of the nozzles 16 is provided by a controller 21 which is itself controlled by a PC 22 running with a dedicated program. As shown in Figure 4 a speed or speed and position sensor arrangement 23,24 of known design is used to detect the rotary motion or the rotary motion and position of the bearing 10 and provides an input to the controller 21. The controller 21 is then enabled to respond to the dynamic rotary speed/position signal generated by the sensor 23,24 so that the control signals operating the spray nozzles 16 likewise respond to the sensed parameter.

Figure 4 also shows the bearing 10 fitted to a shaft 5. In this embodiment, in contrast to that depicted in Figures I to 3, the inner ring 1 I rotates with the shaft 5 while the outer ring 12 is intended to remain stationary.

In Figure 5, the lubrication system is again represented in conjunction with a pair of bearings 10, 10'supporting the shaft 5. The left-hand bearing 10 is again associated with the sensor arrangement 23,24. The right-hand bearing 10'is associated with another sensor arrangement 26,27 which senses some other parameter such as temperature or load. The sensor arrangement

26,27 also provides signals to the controller 21 so the controller 21 can respond to these signals and control the emission of lubricant accordingly.

CLAIMS 1. A lubrication system for use with a bearing, said system including a plurality of lubricant spray nozzles provided with switching means to enable the individual nozzles to emit a spray of lubricant into the bearing.

2. A system according to claim 1, wherein the nozzles are disposed around a circular path or a part circular path at one side of the bearing.

3. A system according to claim 1 or 2, wherein the switching means are responsive to electrical control signals.

4. A system according to claim 3, wherein the switching means are composed of piezoelectric devices each allocated to one of the spray nozzles or a set of such nozzles.

5. A system according to claim 3, wherein the switching means are composed of thermal devices each allocated to one of the spray nozzles or a set of such nozzles.

6. A system according to claim 3, wherein the switching means are composed of microvalves each allocated to one of the spray nozzles or a set of such nozzles.

7. A system according to any one of the preceding claims, wherein the nozzles are arranged in sets or arrays, each set or array of nozzles being mounted on a unit.

8. A lubrication system according to claim 7, wherein the mounting untis are carried by a support ring mounted alongside the bearing.

9. A lubrication system according to any one of the preceding claims and further comprising a controller which serves to operate the nozzles selectively.

10. A lubrication system according to claim 9 when appended to claim 3, wherein the controller provides the electrical control signals for actuating the switching means.

11. A lubrication system according to claim 10, wherein the controller is subjected to computer program controlled functions.

12. A lubrication system according to claim 10 or 1 I, wherein the controller also receives signals from a sensor at least detecting rotary speed or position of the bearing and the controller is adapted to respond to the signals from the sensor.

13. A lubrication system according to claim 10 or ll, wherein the controller also receives signals from a sensor detecting rotary speed and position of the bearing.

14. A lubricating system according to claim 12 or 13, wherein the controller also receives signals from another sensor or sensor arrangement responsive to some other parameter affecting lubrication.

15. A lubrication system substantially as described herein with reference to, and as illustrated in the accompanying drawings.

16. A rotary bearing in combination with a lubrication supply system according to any one or more of the preceding claims.

17. A method of automatically lubricating a bearing; said method comprising selectively actuating one or more lubricant spray nozzles in succession with the aid of controllable switching means as the bearing is operating.

18. A method according to claim 17, wherein the nozzles are actuated by switching means responsive to electrical control signals provided by a controller.

19. A method according to claim 18 and further comprising subjecting the controller to computer control.

20. A method according to claim 18 or 19 and further comprising providing signals to the controller from a rotary speed or position sensor and causing the controller to change the control signals in response to the signals from the sensor.

21. A method of automatically lubricating a rotary bearing substantially as herein described and with reference to any one or more of the Figures of the accompanying drawings.

Claims

Amendments to the claims have been filed as follows CLAIMS I. A lubrication system for use with a bearing, said system including a plurality of lubricant spray nozzles and switching or enabling means to enable individual nozzles selectively to emit a spray of lubricant into the bearing, wherein the switching or enabling means takes the form of piezo-electric devices, thermal devices or micro-valves each allocated to one of the spray nozzles or a set of such nozzles and responsive to electrical control signals.
2. A system according to claim 1, wherein the nozzles are disposed around a circular path or a part circular path at one side of the bearing.
3. A system according to any one of the preceding claims, wherein the nozzles are arranged in sets or arrays, each set or array of nozzles being mounted on a unit.
4. A lubrication system according to claim 3, wherein the mounting units are carried by a common support mounted alongside the bearing.
5. A lubrication system according to any one of the preceding claims and further comprising a controller which serves to provide the control signals.
6. A lubrication system according to claim 5, wherein the controller is subjected to computer program controlled functions.

<Desc/Clms Page number 11>
7. A lubrication system according to claim 5 or 6, wherein the controller also receives signals from a sensor at least detecting rotary speed or position of one or more components of the bearing and the controller is adapted to respond to the signals from the sensor.

1
8. A lubrication system according to claim 5 or 6, wherein the controller also receives signals from a sensor detecting motion of the bearing.
9. A lubricating system according to claim 5,6, 7 or 8, wherein the controller also receives signals from another sensor or sensor arrangement responsive to some other parameter affecting lubrication.
10. A lubrication system substantially as described herein with reference to, and as illustrated in the accompanying drawings.
11. A rotary bearing in combination with a lubrication supply system according to any one or more of the preceding claims.
12. A method of automatically lubricating a bearing; said method comprising selectively actuating one or more lubricant spray nozzles in succession with the aid of controllable switching or enabling means as the bearing is operating by providing electrical control signals to piezoelectric devices, thermal devices or micro-valves.

<Desc/Clms Page number 12>
13. A method according to claim 12, wherein the electrical control signals are provided by a controller.
14. A method according to claim 13 and further comprising subjecting the controller to computer control.
15. A method according to claim 13 or 14 and further comprising providing signals to the controller from a rotary speed or position sensor and causing the controller to change the control signals in response to the signals from the sensor.
16. A method of automatically lubricating a rotary bearing substantially as herein described and with reference to any one or more of the Figures of the accompanying drawings.