US3719092A

US3719092A - End plate for gyroscope rotor

Info

Publication number: US3719092A
Application number: US00026209A
Authority: US
Inventors: C Quinby
Original assignee: Lear Siegler Inc
Current assignee: Lear Siegler Inc
Priority date: 1970-04-07
Filing date: 1970-04-07
Publication date: 1973-03-06
Anticipated expiration: 1990-03-06
Also published as: IL36539A; FR2089165A5; CA936020A; IL36539A0; DE2116585A1

Abstract

Support disc or end plate for massive rim of gyroscope rotors that eliminates the cross-coupling effect of radial load causing axial deflection and the resulting change in anti-friction bearing loading. The end plate includes a marginal edge portion having cut-outs defining flexural elements which yield in plane of marginal edge portion rather than in plane perpendicular thereto.

Description

United States Patent Quinby 1 March 6, 1973 1 END PLATE FOR GYROSCOPE ROTOR 3,446,081 5/1969 Oger ..74/5.7

[75] Inventor: Charles E. Quinby, Grand Rapids, 4

Mich.

[73] Assignee: Lear Siegler, Inc., Grand Rapids, Primary E xaminerManueI A. Antonakas Mich. Attorney-Wilfred O. Schmidt [22] Filed: April 7, 1970 ABSTRACT [21 1 Appl' 26209 Support disc or end plate for massive rim of gyroscope rotors that eliminates the cross-coupling effect of radi- U-S- n i "74/5, a] load causing axial deflection and the resulting [51] Int. Cl. ..G0lc 19/00 Change in ami friction bearing loading The end plate [58] Field Of Search ..74/5, 5.7; 310/74, 67; includes a marginal edge portion having cutouts 308/2 A defining flexural elements which yield in plane of marginal edge portion rather than in plane perpendicular [56] References Cited thereto.

UNITED STATES PATENTS 7 Claims, 3 Drawing Figures 2,771,778 11/1956 Ryberg ..74/5

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INVENTOR.

CHARLES E. QUINBY ATTORNEY END PLATE FOR GYROSCOPE ROTOR FIELD OF THE INVENTION This invention relates to gyroscopes and particularly to end discs or end plates for gyroscope rotors.

THE PRIOR ART Gyroscopes are well known. It is also well known to construct gyroscopes wherein the rotor is made of a massive rim like a flywheel, which rim is supported for rotation on a shaft by a pair of end discs or end plates which are carried at their centers by suitable low friction bearings. The end plates are commonly press fit or otherwise connected to the rim. Such a structure is hollow and the stator windings are an integral part of the shaft within the hollow rotor. The end plates, in conjunction with the low friction bearings, function to provide both axial and radial constraint of the rotor rim. However, when thermal expansion or contraction, centrifugal forces, or external shock act upon the massive rim of the gyroscope rotor, the end plates may be sub jected to changing radial compressive forces and the resulting deflection takes place along the shaft axis which cause a buckling. This buckling, commonly known as cross-coupling, changes the low friction bearing preload resulting in premature failure.

It has previously been suggested to provide the end plates with an intermediate highly flexural portion in the form of a web interconnecting the marginal edge portion of the disc and the hub of the end plate so that the flexure will all be taken up in the web (US. Pat. No. 2,771,778). While this significantly improves the structure of the end plates, there is nevertheless still some buckling of the marginal edge portion of the rim, which buckling is transmitted to the hub to result in some cross coupling.

SUMMARY OF THE INVENTION The present invention utilizes an end plate or end disc for the rotor of a gyroscope, which end plate has a marginal edge portion that is provided with a multiplicity of cut-outs to define flexural elements or members which are designed to flex in the plane of the marginal edge portion when subjected to radial compressive forces. Flexural elements of the end plate are subjected to pure bending with buckling and its resultant cross-coupling side effects being completely eliminated. It is also apparent in the present invention that each end plate can contain both a compressive radial force and an axial preload force, simultaneously, without interaction of forces.

In the preferred form of the invention, the marginal edge portion is annular in configuration and the flexural elements are defined by cut-outs in the form of apertures, elongated slots and arcuate cut-outs or scollops therebetween which combine, together with the thickness of the marginal edge portion, to define flexural elements that yield preferentially in the plane of the marginal edge portion.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a vertical sectional view of a gyroscope embodying a rotor including end plates made in accordance with the present invention;

FIG. 2 is a plan view of an end plate embodying the present invention; and

FIG. 3 is a side elevational view thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing in detail, a gyroscope 10 includes a gimbal 12 supporting a fixed shaft 14. A rotor 16 is carried on the shaft 14 and includes a heavy rim 18 in order to position the revolving mass at the greatest practical distance from the axis, whereby to obtain a maximum angular momentum, and a pair of end discs 20. The end discs 20 are of annular form and are secured to the rim 18 and to the low-friction bearings 22 mounted on the shaft 14. The position of the rotor 16 is fixed along the axis of the shaft 14 by constraining the inner races of the low friction bearings 22. An interference fit exists between the end plates 20 and the concentric cavities 28 of the rim 18. The shaft 14 also supports a fixed winding 24 as an integral part of the stator and the rim 18 has, as an integral part the rotor lamination stack 26, as is well known.

The rim 18 is designed to withstand centrifugal forces to which it may be subjected. In operation, heat is generated in the stator and is dissipated by conduction, convection, and radiation establishing thermal gradients throughout the rotor 16. These thermal gradients produce stress regions and in conjunction with the centrifugal induced stresses, in the absence of the invention improvement, produce deformation of the end plates 20 along the axis of the shaft 14, herein referred to as cross-coupling. Such deformation may occur either inwardly or outwardly, but in any case it is unpredictable as to degree and configuration. Outward deformation of the end plates 20 may in some cases be inperceptable because of bearing constraint, but the increased load on the bearing is responsible for heat generation that will rapidly raise the bearing temperature to the point of seizure. Inward deformation of the end plates 20 permits a random axial shift of the rim 18 which gives an erratic and unacceptable performance characteristic.

It has been found that the principal, if not the exclusive force causing cross-coupling is exerted virtually normal to the axis of rotation and is probably due solely to those forces exerted by the rim. These forces may be the result of differential centrifugal forces, thermal expansion, or both. It is also possible that since the rim is fixed at its edges, radial deflection is maximum at its center, thereby instrumenting deflection of the end discs.

In accordance with the present invention, means are provided at the rim of the end plates 20 to flex in the plane of the rim to accommodate to expansions and contractions in the rim without resulting in the crosscoupling of the end plates per se. Specifically, the rim or marginal edge portion 30 of the end plate 20 which is joined to the hub 32 thereof by a web 34, is shaped or provided with a multiplicity of cut-outs so as to cause the rim 30 to be made up of a plurality of short flexural elements or spring arms 36, each of which is designed to flex in the plane of the rim 30 rather than in the plane perpendicular thereto. As shown, hub 32 is provided with an aperture 38 which receives a bearing 22 as with a press fit to secure the end plate 20 to its respective bearing.

Referring now specifically to FIG. 2, it will be seen that the rim 30 of the end plate 20 is shaped to define the plurality of flexural elements 36 (here shown as 48 in number) by a series of cut-outs in the form of circular apertures 40, slots 42 which extend from said apertures to the outer edge of said rim, and a multiplicity of arcuate cut-outs 44 which are disposed between the slots 42. The diameter of the apertures 40, the width of the slots 42 and the extend of peripheral penetration of the arcuate cut-outs 44 are such, when taken together with he thickness of the rim 30, as to proportion the flexural elements 36 so that when they are subjected to a force which is radial of the end plate 20, the spring arm will bend or yield in the plane of the rim 30 to narrow the slots 42. Bending of the spring arms or flexural elements 36 occurs only in the plane of the applied force and has no normal component to stress the hub 32 or cause any cross-coupling In other words, the axes of movement of the flexural elements 36 are substantially perpendicular to the plane of the rim 30.

It will be obvious to the skilled art worker that the means for defining the flexural elements 36, including the apertures 40, the slots 42, and the cut-outs 44, could all be defined at the same time as by a single punching operation from a steel disc. The disc itself could be formed into the modified concave or dishlike shape as by forging or the like. Clearly, in lieu of punching, broaching, milling or other machine operations could be employed in forming the end plate 20.

It will also be recognized by the skilled art worker tat the flexural elements 36 need not be formed by round holes 40, straight radial slots 42, and arcuate cut-outs 44. Rather, any means for shaping rim 30 to define the flexural elements which will flex in the plane of the rim 30 when subjected to radial forces comes within he scope of the present invention. It is desirable that the flexural elements be shaped so that a portion thereof be subjectable to radial forces, such as the portion 46, and that the rim 30 be shaped so that the flexural elements are able to operate substantially independently of one another. With these criteria recognized by the skilled art worker, the particular form of means for defining the flexural elements 36 will be a matter of design choice.

As an example of one form of end plate which I have found to be eminently satisfactory in accordance with the present invention, is a disc as above described with the following dimensions, having reference to the drawings:

A 2.565 inches 8 1.950 inches C L66 inches D 0.095 inches E 0.095 inches F 0.3ll inches 0.125 inches H 1.030 inches l 0.l50 inches J 0.050 inches K 0.375 inches l As shown and as preferred, the circular apertures 40 are twenty four in number and are equally spaced at intervals, and the arcuate cut'outs 44 are disposed equidistant between adjacent apertures 40. Moreover, the slots 42 are all radially extending and each of their main axes pass through the center of the aperture 40 which each slot communicates. It will be obvious that this one special and highly useful embodiment of the present invention but the dimensions set forth above are in no way presented by way of limitation, they being presented by way of illustration of the presently preferred embodiment of the invention.

To assemble rotor 16, the end plates 20 may be pressed into cavities 28, in the rim 18 to forming an interference fit, the three components being held together by virtue of the resiliency of the flexural element 36. Bearings 22 are pressed into apertures 38 in the hubs 32 of the discs 20 and the rotor assembly. With such an assembly, it is obvious that the rim 18 will carry the great concentration of weight for the rotor 16 and the entire rotor will be able to rotate freely on the comparatively frictionless ball bearings 22.

Having described the invention and the method of manufacturing same, it will be obvious to those skilled in the art that various changes and modifications may be made therein within the scope of the appended claims without departing from he spirit and scope of this invention.

What is claimed is:

1. In a gyroscope or the like having its rotating mass concentrated principally in the annular rim of a rotating member in the form of a hollow flywheel, and in which the member serves as the rotor with respect to a fixed stator mounted internally of the rotor, said stator having a rotor support means and means for mounting said rotating member on said rotor support means, the improvement comprising: said mounting means including a disc supporting said rim for the rotation about the axis of rotation, said disc having a substantially planar and unitary marginal edge portion including a plurality of outwardly extending flexural elements proportioned to flex in the plane of said marginal edge portion and about axis substantially perpendicular to said planar edge portion in response to a radial compressive force.

2. The gyroscope of claim 1, wherein said marginal edge portion is annular, and said flexural elements are defined by cut-outs therein.

3. The gyroscope of claim 2, wherein said cut-outs include a plurality of equispaced apertures in said marginal edge portion, a plurality of radially extending slots, one for each aperture, extending from said apertures to the peripheral edge of said disc, and a plurality of arcuate cut-outs in said peripheral edge disposed equidistant between said apertures.

4. The gyroscope of claim 1, wherein said disc further includes a hub disposed in a plane substantially parallel to said marginal edge portion, and a web connecting said hub to said marginal edge portion.

5. The gyroscope of claim 4, wherein said marginal edge portion, said web and said hub are integral.

6. The gyroscope of claim 5, wherein said marginal edge portion is annular, andsaid flexural elements are defined by cut-outs therein.

7. The gyroscope of claim 6, wherein said cut-outs include a plurality of equispaced apertures in said marginal edge portion, a plurality of radially extending slots, one for each aperture, ending from said apertures to the peripheral side edge of said disc, and a plurality of arcuate cut-outs in said peripheral edge disposed equidistant between said apertures.

Claims

6. The gyroscope of claim 5, wherein said marginal edge portion is annular, and said flexural elements are defined by cut-outs therein.