End shield for an electrical machine having coplanar brackets and bearing opening
View Patent ↗In an arrangement in an electrical machine, the electrical machine includes a rotor rotating around its shaft, a stator located from the rotor at an air gap, and a frame around the outer surface of the stator. A stator opening is formed in the end of the frame, and the stator opening is closeable with a cast end shield. The end shield includes at least three brackets protruding from the outer edge of the end shield. The brackets are fittable onto the end junctions where axially continuing structures are connected to the end at the junctions.
1. A cast end shield configured for an electrical machine, for closing a stator opening formed in an end of a frame of the electrical machine and for supporting a bearing that is to support a rotor, the end shield comprising:
an opening in a middle for a bearing supporting a shaft of a rotor;
an inner rim limited by the opening;
a further rim connecting to the inner rim, the further rim extending up to an outer edge of the end shield; and
at least three brackets protruding smoothly from the outer edge of the end shield in a radial direction for transferring a bending stiffness to a side of the end shield, the brackets being fitted for an electrical machine frame end, wherein the opening for the bearing, and a plane perpendicular to the shaft and passing through a face of the at least three brackets configured to be facing the electrical machine, are arranged to be co-planar.
2. The end shield according to claim 1 , wherein the further rim comprises:
reinforcements in the radial direction, protruding in an axial direction and connecting to the brackets.
3. The end shield according to claim 2 , comprising:
a ring for at least partially surrounding a bearing and surrounding the opening; and
at least three reinforcements connected to the ring that is to surround the bearing, the cross-section of the reinforcements being substantially U-shaped.
4. An end shield according to claim 3 , wherein sidewalls of the reinforcements are joined during a casting of the end shield to a surface of the further rim.
5. The end shield according to claim 2 , wherein sidewalls of the reinforcement are joined during a casting of the end shield to a surface of the further rim.
6. The end shield according to claim 2 , wherein a width of the reinforcements, measured in a direction of circumference, changes in the radial direction.
7. An end shield according to claim 2 , wherein the end shield includes a bracketless sector, the sector formed of an angle (α) of at least 150°.
8. The end shield according to claim 1 , wherein the end shield includes a bracketless sector, the sector formed of an angle (α) of at least 150°.
9. The end shield according to claim 1 , wherein the bracket's axial height (s) is equal with or larger than an axial height (w) of an outer edge at the bracket.
10. The end shield according to claim 1 , wherein the brackets are made of solid material.
11. The end shield according to claim 1 , comprising:
an additional reinforcement attached to a ring that is to at least partially surround a bearing, wherein the additional reinforcement reaches the outer ring of the end shield, and a cross-section of the additional reinforcement is substantially U-shaped, solid or flat.
12. The end shield according to claim 1 , wherein three brackets are on a same side of a centerline (k) dividing the end shield into two.
13. An electrical machine, comprising:
a rotor for rotating around a shaft;
a stator spaced from the rotor at an air gap;
a frame around an outer surface of the stator, a stator opening being formed in an end of the frame;
a cast end shield for closing the stator opening wherein the end shield comprises:
an opening in a middle for a bearing supporting the shaft, the opening being surrounded by a ring that is to at least partially surround the bearing; and
at least three brackets protruding smoothly from an outer edge of the end shield for transferring a bending stiffness to a side of the end shield, the brackets being fittable onto end junctions where axially continuing structures are connected to the frame end at the junctions, wherein the opening for the bearing, and a plane perpendicular to the shaft and passing through a face of the at least three brackets facing to the electrical machine, are arranged to be co-planar.
14. The electrical machine according to claim 13 , wherein the end of the frame includes a flat plate.
15. The electrical machine according to claim 13 , wherein the frame is a housing formed of plates.
16. The electrical machine according to claim 15 , wherein the axially continuing structures comprise:
a roof plate;
a side plate; and
a bottom plate.
17. The electrical machine according to claim 16 , wherein part of a bracketless sector of the end shield is on a junction of the frame end and the bottom plate.
18. The electrical machine according to claim 15 , wherein the end shield, comprises:
four brackets, two of the brackets being fitted onto the junction of the frame end and a roof plate.
19. The electrical machine according to claim 13 , wherein the brackets are fitted onto the junction of the frame end and a support plate, and the support plate connects to a next cross-directional wall in the axial direction.
20. The electrical machine according to claim 13 , wherein the end shield comprises:
at least three reinforcements connected to the ring that is to surround the bearing, a cross section of the reinforcements being substantially U-shaped, and the reinforcements reaching the outer ring of the end shield, and the reinforcements connecting to a fastener in the outer ring, and the fastener forming a bracket.