Supporting structure for slow speed large diameter electrical machines

• US 4,258,280 A
• Filed: 12/23/1977
• Issued: 03/24/1981
• Est. Priority Date: 11/07/1975
• Status: Expired due to Term

• Current Assignee: BBC Brown Boveri & Company Limited (ABB Limited)
• Original Assignee: BBC Brown Boveri & Company Limited (ABB Limited)
• Inventors: Starcevic, Mihailo
• Primary Examiner(s): Skudy, R.
• Application Number:
  US05/863,745
• Time in Patent Office: 1,187 Days
• Field of Search: 310/157, 310/254, 310/90, 310/91, 310/258, 310/259, 310/89, 310/261, 248/7, 248/26
• US Class Current: 310/157
• CPC Class Codes: F16M 1/04 for rotary engines or similar machines
• CPC Class Codes: H02K 5/00 Casings; Enclosures; Supports
• CPC Class Codes: Y10S 174/19 in a dynamo-electric machine

Abstract

A supporting structural component such as a bearing for the rotor of a slow speed large diameter electrical machine the rotor of which rotates about a vertical axis comprises concentric inner and outer rings joined by rigid rectilinear spoke-like connecting elements spaced uniformly around THE circumference. The arrangement of these connecting elements is such that they are tangent to the surface of an imagined coaxial cylinder the diameter of which is smaller than that of the inner ring, and the axes of two neighboring connecting elements when imagined as extended in a straight line over both rings intersect only within the inner ring. The connecting elements are inflexible over their whole effective length in the longitudinal direction corresponding to the applied load. Also, the respective axes of all of the spoke-like connecting elements lie at identical acute angles and in the same sense to radii of the inner and outer rings.

Claims

1. An arrangement for mounting the stator and rotor of a rotary electrical machine of the vertical axis type having a form which is generally rotationally symmetrical, said arrangement comprising an outer ring rigid and fixedly secured and two axially spaced inner rings, said outer ring supporting the machine stator and said two axially spaced inner rings arranged concentrically within said outer ring and supporting the machine rotor, means for interconnecting said outer ring with each of said two axially spaced inner rings, said means for interconnecting including a plurality of rigid rectilinear arms which remain inflexible throughout their entire length when subjected to load, all of said rigid rectilinear connecting arms associated with one of said axially spaced inner rings forming identical acute angles both with respect to radial lines directed from the center of said one of said two axially spaced inner rings through respective junction points with said one of said two axially spaced inner rings and with respect to lines tangent to a circle at the respective junction points, said arms being inclined in the same rotational sense.

2. An arrangement as defined in claim 1 for mounting a rotary electrical machine including means for hingedly securing said rigid rectilinear arms to at least one of said inner and outer rings.

3. An arrangement as defined in claim 2 for mounting a rotary electrical machine further comprising a plurality of tie bars, adjacent junction points of said rigid rectilinear arms with at least one of said rings being joined together by a respective one of said tie bars.

4. An arrangement as defined in claim 3 for mounting a rotary electrical machine wherein each of said plurality of tie bars is adjustable in length.

5. An arrangement as defined in claim 1 for mounting a rotary electrical machine further comprising a plurality of cross braces, said rigid rectilinear arms being divided into a number of sections of which pairs of said sections are joined together at junction points, and the pair of sections are joined in circumferential directions at the junction points by the cross-braces.

6. An arrangement as defined in claim 1 wherein one of said inner rings forms part of a bearing housing structure for the rotor of said rotary electrical machine.

7. An arrangement for mounting a generally rotationally symmetrical component of a rotary electrical machine of the vertical axis type, comprising:

an outer ring, said outer ring being rigid and fixedly secured;

a first inner ring arranged concentrically within the outer ring, said first inner ring supporting a rotor of said rotary electrical machine;

means for interconnecting said outer ring with said first inner ring including a plurality of rigid arms, each of the plurality of rigid arms having a first and a second end, the first end of each of the plurality of rigid arms being connected at a first respective junction point to the outer ring and the second end of each of the plurality of rigid arms being connected at a second respective junction point to the first inner ring, each of said plurality of the rigid arms defining a first acute angle with the first inner ring which first acute angle is greater than a second acute angle formed by a line tangent to the first inner ring at the second respective junction point, with all of the rigid arms being oriented similarly in the same rotational sense.

8. The arrangement of claim 7 wherein each of the plurality of rigid arms remains inflexible throughout its entire length when subjected to a load.

9. The arrangement of claim 8 wherein all of said first acute angles are substantially identical to one another.

10. The arrangement of claim 7 further comprising means for hingedly securing the plurality of rigid arms to the first inner ring.

11. The arrangement of claim 7, further comprising:

a second inner ring axially spaced relative to the first inner ring and arranged concentrically within the outer ring, said second inner ring further supporting the rotor of the rotary electrical machine; and

second means for interconnecting said outer ring with said second inner ring including a plurality of second rigid arms, each of the plurality of the second rigid arms having a first and a second end, the first end of each of the plurality of the second rigid arms being connected at a third respective junction point to the outer ring and the second end of each of the plurality of the second rigid arms being connected at a fourth respective junction point to the second inner ring, each of said plurality of the second rigid arms defining a third acute angle with the second inner ring which third acute angle is greater than a fourth acute angle formed by a line tangent to the second inner ring at the fourth respective junction point, with all of the rigid arms being oriented similarly in the same rotational sense.

12. The arrangement of claim 11 wherein the first and third acute angles are all substantially identical.

13. The arrangement of claim 11 wherein the second inner ring includes a thrust bearing for the rotor of the rotary electrical machine.

14. An arrangement for mounting a generally rotationally symmetrical component of a rotary electrical machine of the vertical axis type, comprising:

an outer ring, said outer ring being rigid and fixedly secured;

a first inner ring arranged concentrically within the outer ring, said first inner ring supporting a rotor of said rotary electrical machine;

means for interconnecting said outer ring with said first inner ring including a plurality of rigid arms, each of the plurality of rigid arms having a first and a second end, the first end of each of the plurality of rigid arms being connected at a first respective junction point to the outer ring and the second end of each of the plurality of rigid arms being connected at a second respective junction point to the first inner ring, each of said plurality of the rigid arms defining a first acute angle with the first inner ring, which first acute angle is greater than a second acute angle formed by a line tangent to the first inner ring at the second respective junction point, with all of the rigid arms being oriented similarly in the same rotational sense; and

a plurality of tie bars, each of said tie bars joining together a pair of adjacent rigid arms at a pair of adjacent first respective junction points on the outer ring.

15. The arrangement of claim 14 wherein each of the plurality of tie bars is adjustable in length.

16. The arrangement of claim 14 further comprising a plurality of cross braces for joining adjacent ones of the plurality of rigid arms together, said plurality of cross braces being arranged in circumferential directions.

17. An electrical machine of vertical construction comprising:

a stator;

a rotor;

an outer ring foundation structure surrounding the stator;

upper guide bearing means for supporting the rotor;

lower thrust bearing means for further supporting the rotor;

both bearing means together include central bodies forming a concentric inner ring structure and a plurality of circumferentially extending and uniformly distributed spoke-like arms, the spoke-like arms being located intermediate said inner ring structure and said outer ring foundation structure;

means for joining opposite ends of said arms to said inner and outer ring structures with respective axes of said arms forming identical acute angles with radial lines extending respectively from the common center of said inner ring structure and said outer ring foundation structure through corresponding joints which join outer ends of said arms with said outer ring foundation structure;

the axes of said arms also forming identical acute angles with lines tangent to a circle at corresponding joints with the inner ring structure;

said arms being inflexible over their whole effective length in the longitudinal direction corresponding to the applied load; and

all of said arms being inclined in the same rotational sense so as to accomodate torsional stresses imposed upon said inner ring structure caused by thermally induced expansion thereof.