WO1998057414A1

WO1998057414A1 - Frictionless bearing system

Info

Publication number: WO1998057414A1
Application number: PCT/US1998/011807
Authority: WO
Inventors: Jeffrey J. Diemer
Original assignee: Diemer Jeffrey J
Priority date: 1997-06-10
Filing date: 1998-06-09
Publication date: 1998-12-17
Also published as: AU8254398A

Abstract

An improved frictionless bearing system comprising a multiplicity of journal bearings (25, 27) and thrust bearings (45). Each journal bearing (25, 27) consists of a shaft magnet (40, 90) enclosed by an outer journal magnet (30, 80) of the same polarity. Each thrust bearing (45) consists of at least one thrust magnet (60, 60') and one or more limit magnets (50, 70), each limit magnet (50, 70) having an opposite polarity to the thrust magnet (60, 60'). The journal bearings (25, 27) support the non-magnetic shaft (20) limiting its movement in the non-axial direction. The thrust bearing (45) further limit motion of the shaft (20) in its axial direction. A non-magnetic mounting (100) element is used to support the outer journal magnets (30, 80) and limit magnets (50, 70) in a fixed position. Similarly, the non-magnetic shaft (20) is fixed to the shaft magnets (40, 60) and thrust magnets (60, 60'). The frictionless bearing system is inexpensive, requires no lubricant, and allows construction of a completely frictionless drive system.

Description

FRICTIONLESS BEARING SYSTEM

BACKGROUND OF THE INVENTION This application claims the benefit under Title 35 United

States Code §119 (e) of U.S. Provisional Application No. 60/049,143, filed June 10, 1997. Technical Field

The present invention relates to a bearing system and more particularly, tσ a frictionless magnetic bearing system which has the capability of providing rotational movement without any physical contact. History of Related Art

Reactions on three-dimensional structures are usually defined in terms of translation and rotation. Some supports and connections are designed primarily to prevent translation, others to prevent rotation, and still others, to prevent both translation and some types of rotation. It is in this latter category that bearings usually are used. Hinges, journal bearings, and roller bearings are usually designed to support radial loads only. Ball bearings and thrust bearings, on the other hand, are used to support axial thrust as well as radial loads .

Bearings can not only be classified by the forces which they exert, but also by the method of their operation, i.e., contact or non-contact. Bearings which depend on contact between the rotating surface and the bearing generate frictional resistance which depends upon the speed of rotation, the clearance between the bearing and the object which it supports, and the viscosity of the lubricant used (if any) .

All contact-dependent bearing systems are relatively inexpensive, but are subject to wear, frictional heating, and drag forces. Ultimately, all such bearing systems must fail.

Non-contact bearing systems, such as air-cushion bearings, do not rely on physical contact between the bearing and the load which it supports. The air cushion bearing, for example, is actually a self-correcting mechanism consisting of an air cushion which acts to re-center the supported object due to high pressure areas which develop under conditions of narrowed air gap loading. This can occur, for example, when a rotor moves off-center toward one wall of the bearing chamber; as it approaches the chamber wall, the air pressure increases where the air gap narrows, while on the other side of the rotor, the air gap widens and pressure is reduced. These changes in pressure tend to re-center the rotor within the chamber. However, the air cushion bearing suffers from several disadvantages, chief among them being the need for an external high-pressure air source to maintain the cushioning effect.

The need, therefore, exists for an inexpensive non-contact system of bearings which can- be implemented so as to prevent bearing failure. The need also exists to implement such a system which is not necessarily dependent on an exterior source of energy to maintain separation between the bearings and the load they support. Further, the need exists for a bearing system which requires no lubricant to operate indefinitely; this eliminates another possible failure mechanism and provides a bearing system which can be used in microscopically clean environments.

SUMMARY OF THE INVENTION

The present invention provides an improved non-contact bearing system which makes use of magnetic force to separate the load from its supporting elements. More particularly, the present invention comprises a series of bearing elements, to include various combinations of journal bearings and thrust bearings, to support loads attached to a non-magnetic shaft.

The journal bearings of the instant invention generally consist of a cylindrical shaft magnet which is enclosed by a hollow, cylindrical magnet of the same polarity. These bearings can also be fabricated utilizing shapes other than cylinders. The thrust bearings of the invention generally consist of a pancake-shaped thrust magnet attached to the same, non-magnetic shaft, in close proximity to at least one pancake- shaped limiting magnet of opposite polarity; thrust bearings also can be fabricated utilizing shapes other than pancakes. The frictionless bearing system of the present invention may be used to support varying loads at varying speeds of rotation. The limitations on loading will depend on the magnetic repulsive force established between the various elements of the thrust and journal bearings. The amount of load supported by the bearing system will also be determined by the air gap between the bearing elements and the surface area of the bearing elements as they relate to one another.

Further, while permanent magnets can be used to form the bearing system, electromagnets can also be used. Although providing for much greater load-bearing capacity, electromagnets require commutator brushes, which add a small amount of friction to the bearing assembly.

The frictionless bearing system of the present invention also includes a non-magnetic mounting element to which certain bearing elements are fixed in place. Any type of mount for the fixed bearing elements which does not detract from the magnetic field interaction of the bearings can be used.

Accordingly, the present invention provides an improved frictionless bearing system which can be produced inexpensively and will not fail due to contact between moving parts. The bearing system can support more or less weight depending on the design of the individual bearing elements, to include the magnetic permeability of the materials used, the size of the elements, and the physical distance between the elements. No lubrication is needed, and no external source of energy is required to maintain separation between the elements, except in the electromagnetic embodiment of the present invention.

These together with other objects and advantages of the present invention will become subsequently apparent in the details of construction and operation as more fully hereinafter described and claimed. Other improvements provided by the present invention will become apparent in the following specifications when considered in light of the attached drawings, wherein a preferred embodiment of the invention is illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the structure and operation of the present invention may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of the present invention with a horizontal axis of rotation;

FIG. 2 is a perspective view of the present invention with a vertical axis of rotation;

FIG. 3 is an alternative embodiment of the present invention with a horizontal axis of rotation; DESCRIPTION OF THE PREFERRED EMBODIMENT

Fig. 1 illustrates a perspective view of the present invention utilizing a horizontal axis of rotation. The frictionless bearing system 10 as illustrated in FIG. 1, comprises a first journal bearing 25, a second journal bearing 27 and a thrust bearing 45 which serve to isolate first load 110 and second load 120, mounted to non-magnetic shaft 20, from non-magnetic mount element 100.

As shown in Fig. 1, journal bearing 25, comprising first shaft magnet 40 attached to the shaft 20, and first outer journal magnet 30 serves to isolate first load 110 from nonmagnetic mount element 100. The operation of first journal bearing 25 depends upon the repulsive force generated between first shaft magnet 40 and first outer journal magnet 30, which are of the same magnetic polarity (negative and positive poles aligned) . The load-bearing capability of first journal bearing

25 depends upon the magnetic permeability of the material used to construct first journal bearing 25, the relative surface areas of first shaft magnet 40 and first outer journal magnet 30, and the air gap distance between magnets 30 and 40. First shaft magnet 40 is fixed or attached to the non-magnetic shaft 20; the first outer journal magnet 30 is fixed to the nonmagnetic mount element 100.

The second journal bearing 27 functions in a manner which mirrors that of the first journal bearing 25. The second shaft magnet 90 is fixed or attached to the non-magnetic shaft 20.

The second outer journal magnet 80 is hollow and surrounds the second shaft magnet 90. The repulsion force which exists between the magnetic elements 80 and 90, which are of the same polarity (poles aligned) , serves to isolate the rotation of the second load 120 from the non-magnetic mount element 100.

The first journal bearing 25 and the second journal bearing 27 act to oppose translational motion of the non- magnetic shaft 20 in all directions, except that which is parallel to the longitudinal axis of the shaft 20. To counteract this longitudinal force, thrust bearing 45 is used. The thrust bearing 45 comprises first and second limit magnets 50 and 70 in combination with the thrust magnet 60. The first and second limit magnets 50 and 70 are fixed to the non-magnetic mount element 100, while the thrust magnet 60 is fixed or attached to the non-magnetic shaft 20 between the journal bearings 25 and 27, as shown in Fig. 1. The magnetic forces imposed by the first and second limit magnets 50 and 70 are directly opposite to that imposed by the thrust magnet 60. That is, the first and second limit magnets 50 and 70 have an opposite magnetic polarity to that of the thrust magnet 60

(negative pole faces negative pole, or positive pole faces positive pole) . As is the case with the first and second journal bearings 25 and 27, the amount of axial translational force which can be opposed by the thrust bearing 45 is dependent upon the magnetic properties of the elements which compose the thrust bearing 45, combined with their physical size and proximity. To impart motion to the first and second loads 110 and

120, belts, pulleys, gears, or other directly-connected mechanical devices can be attached to the shaft 20. In addition, either of the loads 110 or 120 can be magnetized, or a device which reacts to magnetic force (e.g., coil, magnet, etc.) can be implanted within the loads 110 or 120, or within non-magnetic shaft 20, to react to an externally-applied magnetic force which causes rotation of the shaft 20.

A vertical implementation of the frictionless bearing system 10 can be seen in Fig. 2. In this case, the first and second journal bearings 25 and 27, attached to the shaft 20 and the non-magnetic mount 100, are used to support first load 110 so as to allow rotation about the longitudinal axis of the nonmagnetic shaft 20. However, instead of using a thrust bearing which requires two limit magnets (as shown in Fig. 1) , the thrust bearing 45 in this case comprises only the first limit magnet 50, attached to the non-magnetic mount 100, and the thrust magnet 60, attached to the shaft 20, and separated by air gap 55. The magnetic force between the magnets 50 and 60 is countered by the gravitational force upon first load 110 and, ideally, maintains the frictionless bearing system 10 in suspended equilibrium. The strength of magnetic repulsion between the first limit magnet 50 and the thrust magnet 60 in this case must usually be greater than that required for the system shown in 'Fig. 1.

The frictionless bearing system 10 illustrated in Fig. 2 is intended primarily for first loads 110 which are fairly lightweight. For greater stability, the axial distance between the first journal bearing 25 and the second journal bearing 27 should be maximized.

A variation on the frictionless bearing system 10 illustrated in Fig. 2 may be implemented so as to obviate the need for the second journal bearing 27. In this case, the first limit magnet 50 consists of a bowl-shaped element, while the thrust magnet 60 consists of a hemisphere, each element being of opposite polarity and contoured so that the thrust magnet 60 fits into the first limit magnet 50. This alternative embodiment (not illustrated) could be used for frictionless bearing systems 10 which are intended to support extremely lightweight first loads 110. Fig. 3 illustrates another embodiment of the frictionless bearing system 10. In this case, the non-magnetic shaft 20 is limited in its movement (except along the axial direction) by the first and second journal bearings 25 and 27. However, two separate thrust bearings, consisting of first limit magnet 50 in combination with a first thrust magnet 60 (separated by an air gap 55) and a second limit magnet 70 in combination with a second thrust magnet 60' (also separated by an air gap 55) , are used to oppose axial motion. The first load 110 is centered between the first and second journal bearings 25 and 27. In this implementation, the first limit magnet 50 and the thrust magnet 60 are of opposite polarity (negative facing negative, or positive facing positive). Likewise, the second limit magnet 70 and the second thrust magnet 60 are of opposite polarity. This particular implementation of frictionless bearing system 10 provides a greater amount of axial force resistance than that which can be achieved by the embodiments illustrated in Figs. 1 and 2.

Other embodiments of the frictionless bearing 10 system are anticipated by the present invention. These include rotational shafts which are supported by a multiplicity of journal bearings, and a multiplicity of thrust bearings, as needed. That is, for a particular amount of axial restraint, coupled with physical size limitations, it may be desirable to implement a frictionless bearing system 10 which utilizes several thrust bearings 45. Likewise, for a shaft which may rotate quite rapidly, coupled with a slightly unbalanced load, it may be prudent to implement a frictionless bearing system 10 which makes use of several sets of journal bearings 25 and 27. /57414

Any material having magnetic properties can be used to construct the individual elements of the journal bearings or thrust bearings ■ of the frictionless bearing system 10. If electromagnetic implementation is desired, then non-magnetic materials can also be used, as long as they have embedded within them some type of coil or other device which responds to magnetic fields.

In similar fashion, the materials used to construct the nonmagnetic mount element 100 and the non-magnetic shaft 20 do not necessarily have to be entirely non-magnetic. That is, they may consist of materials with magnetic properties, as long as those properties do not interfere with the actions of the magnetic fields essential to the operation of the frictionless bearing system 10. In fact, it may be desirable to construct a shaft 20 consisting of partially magnetic materials to implement a totally frictionless drive system (e.g. part of the shaft is actually driven by an external rotating magnetic field) as mentioned previously, it should also be noted that the loads imposed on the frictionless bearing system 10 may be either magnetic, or non-magnetic, as long as the operational movement of the load does not interfere with the magnetic properties essential to the operation of the frictionless bearing system 10.

Finally, the present invention anticipates other shapes of magnets than cylinders and pancakes. That is, concave and convex hemispheres can be used for the construction of thrust bearings; ellipsoid shapes can also be used. Basically, any type of symmetrical solid with a curved surface (preferred) can be used to form the thrust and journal bearings of the present invention.

The present invention also anticipates the use of other than horizontal ^' or vertical orientations for a frictionless bearing system 10. That is, depending on the relative weight of the frictionless bearing system 10 elements, the weight of the attached loads, and the magnetic forces generated by the thrust and journal bearings, it is possible to implement a frictionless bearing system 10 which has an axis of rotation which is oriented at some angle between 0° and 90° from horizontal. The variation of the frictionless bearing system 10 illustrated in Fig. 2, as described previously and implemented so as to obviate the need for more than a single journal bearing, lends itself readily to an angularly-oriented axis of rotation, of course, any of the bearing systems 10, as illustrated in Figs. 1, 2 and 3, can be utilized in a non- horizontal or non-vertical orientation. Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. The various modifications of the disclosed embodiments, as well as alternative embodiments of the invention will become apparent to persons skilled in the art upon reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention.

Claims

CLAIMSWhat I Claim is:

1. A frictionless bearing system, comprising: a plurality of journal bearings, each one of said plurality of journal bearings having a shaft magnet and an outer journal magnet, the outer journal magnet having the same polarity as the shaft magnet and acting to contain the motion of the shaft magnet in a non-axial direction; a plurality of thrust bearings, each one of said multiplicity of ^' thrust bearings having a limit magnet and a thrust magnet, the limit magnet having an opposite polarity to the thrust magnet ; a shaft attached to the shaft magnets and the thrust magnets; and a mounting element attached to at least one of the outer journal magnets and at least one of the limit magnets.

2. The frictionless bearing system of Claim 1, wherein the thrust bearings and the journal bearings are electromagnetic.

3. A frictionless bearing system comprising: a shaft ; a first journal bearing attached to the shaft; a second journal bearing attached to the shaft; and a thrust bearing attached to the shaft between the first and second journal bearings.

4. The frictionless bearing system of Claim 3, further comprising a non-magnetic mount element, and wherein the thrust bearing comprises : a first limit magnet attached to the non-magnetic mount element ; a second limit magnet attached to the non-magnetic mount element; and a thrust magnet attached to the shaft .

5. The frictionless bearing system of Claim 3, further comprising: a magnet implanted within the shaft .

6. The frictionless bearing system of Claim 3, further comprising: a coil implanted within the shaft.

7. A vertical frictionless bearing system comprising: a shaft; a non-magnetic mount element; a thrust bearing attached to the shaft and the nonmagnetic mount element; and a first journal bearing attached to the shaft and the non-magnetic mount element.

8. The vertical frictionless bearing system of Claim 7, wherein the thrust bearing comprises: a limit magnet attached to the non-magnetic mount element; and a thrust magnet attached to the shaft .

9. The vertical frictionless bearing system of Claim 8, wherein the thrust magnet is a hemisphere, and the limit magnet is bowl -shaped.

10. The vertical frictionless bearing system of Claim 7, further comprising a second journal bearing attached to the shaft .

11. A frictionless bearing system comprising: a shaft; a first thrust bearing attached to the shaft; a second thrust bearing attached to the shaft; and a first journal bearing attached to the shaft between the first and second thrust bearings.

12. The frictionless bearing system of Claim 11, further comprising: a non-magnetic mount element, and wherein the first and second thrust bearings each comprise: a limit magnet attached to the non-magnetic mount element; and a thrust magnet attached to the shaft .

13. The frictionless bearing system of Claim 11, further comprising: a magnet implanted within the shaft .

14. The frictionless bearing system of Claim 11, further comprising : a coil implanted within the shaft.

15. The frictionless bearing system of Claim 11, further comprising : a second journal bearing attached to the shaft between the first and second thrust bearings.

16. The frictionless bearing system of Claim 15, further comprising : a magnet implanted within the shaft .

17. The frictionless bearing system of Claim 15, further comprising: a coil implanted within the shaft.

18. A frictionless bearing system, comprising: a plurality of journal bearings, each one of said plurality of journal bearings having a shaft magnet and an outer journal magnet, the outer journal magnet having the same polarity as the shaft magnet and acting to contain the motion of the shaft magnet in a non-axial direction; a thrust bearing having a limit magnet and a thrust magnet, the limit magnet having an opposite polarity to the thrust magnet; a shaft attached to the shaft magnets and the thrust magnet; and a mounting element attached to at least one of the outer journal magnets and the limit magnet.

19. The frictionless bearing system of Claim 18, wherein the thrust bearing is electromagnetic.

20. The frictionless bearing system of Claim 18, wherein the journal bearings are electromagnetic.

21. A frictionless bearing system, comprising: a journal bearing having a shaft magnet and an outer journal magnet, the outer journal magnet having the same polarity as the shaft magnet and acting to contain the motion of the shaft magnet in a non-axial direction; a plurality of thrust bearings, each one of said multiplicity of thrust bearings having a limit magnet and a thrust magnet, the limit magnet having an opposite polarity to the thrust magnet ; a shaft attached to the shaft magnet and the thrust magnets; and a mounting element attached to the outer journal magnet and at least one of the limit magnets.

22. The frictionless bearing system of Claim 21, wherein the thrust bearings are electromagnetic.

23. The frictionless bearing system of Claim 18, wherein the journal bearing is electromagnetic.