Alternator and method of manufacture

• US 20040169429A1
• Filed: 03/05/2004
• Published: 09/02/2004
• Est. Priority Date: 03/16/2001
• Status: Active Grant

• Current Assignee: Altech Generating Systems LLC
• Original Assignee: Altech Generating Systems LLC
• Inventors: Howe, Steven E., Lipscomb, Donald C. Jr.
• Granted Patent: US 6,849,974 B2
• Time in Patent Office: Days
• US Class Current: 310/89
• CPC Class Codes: F16C 19/06 with a single row or balls
• CPC Class Codes: F16C 2226/30 Material joints
• CPC Class Codes: F16C 2380/26 Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators
• CPC Class Codes: F16C 35/045 with a radial flange to mount the housing
• CPC Class Codes: F16C 35/067 Fixing them in a housing with interposition of an element F16C35/07
• CPC Class Codes: F16C 41/002 Conductive elements, e.g. to prevent static electricity
• CPC Class Codes: H02K 11/0141 Shields associated with casings, enclosures or brackets
• CPC Class Codes: H02K 15/14 Casings; Enclosures; Supports
• CPC Class Codes: H02K 19/36 Structural association of synchronous generators with auxiliary electric devices influencing the characteristic of the generator or controlling the generator, e.g. with impedances or switches
• CPC Class Codes: H02K 5/08 Insulating casings
• CPC Class Codes: H02K 5/141 for cooperation with slip-rings
• CPC Class Codes: H02K 5/15 Mounting arrangements for bearing-shields or end plates
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine
• CPC Class Codes: Y10T 29/49012 Rotor

Abstract

An alternator has a molded plastic, electrically conductive D.E. frame in which a sealed bearing is molded in place with the formation of the D.E. frame 14. When the D.E. frame is removed from its plastics injection mold and while the frame is still hot, the stator is installed in the D.E. frame and the frame allowed to cool and constrict about the stator. The companion S.R.E. frame is preferably fabricated of non-conductive plastics material.

Claims

1. A method of fabricating an alternator comprising:

preparing a stator;

molding a drive-end (D.E.) frame of plastics material in a mold;

removing the molded D.E. frame from the mold and, while the D.E. frame is still hot from heat imparted by molding, installing the stator in the D.E. frame and permitting the D.E. frame to cool and constrict about the stator to secure the stator to the D.E. frame

2. The method of claim 1 in which the stator includes a plurality of channels, and forming the D.E. frame with a locator rib.

3. The method of claim 2 wherein prior to installing the stator in the D.E. frame, manipulating the stator to locate the stator in a predetermined angular position relative to the D.E. frame corresponding to angular alignment of a portion of the stator with the locator rib, and securing the stator in the predetermined angular position by disposing the locator rib in an associated one of the channels of the stator corresponding to such predetermined angular position upon installing the stator in the D.E. frame.

4. The method of claim 1 including molding a sealed bearing having an inner race, and outer race, and rolling elements between the inner and outer races in the D.E. frame during the molding of the D.E. frame and controlling the temperature of the bearing to prevent damage to the bearing from molding.

5. The method of claim 1 including forming a grounding portion on the D.E. housing and forming an electrically conductive ground circuit from the stator to the grounding portion of the D.E. frame.

6. The method of claim 5 wherein the ground circuit is formed by molding the D.E. frame from an electrically conductive plastics composite material as the plastics material.

7. The method of claim 5 wherein the ground circuit is formed by molding an electrically conductive wire in the D.E. frame during the molding of the frame.

8. A method of fabricating an alternator comprising:

providing a sealed bearing having an inner race, an outer race, and lubricated rolling elements disposed between the inner and outer races;

inserting the sealed bearing in a mold configured to form a plastics drive-end (D.E.) frame of the alternator; and

introducing hot, flowable plastics material into the mold and molding the plastics material about the outer race of the sealed bearing to secure the bearing to the resultant molded plastics D.E. frame, while controlling the heat in the mold to protect the bearing against heat damage.

9. The method of claim 8 including molding a bearing well in the D.E. frame including side walls surrounding an outer surface of the outer race of the bearing and a retainer portion projecting radially inwardly from the wall at opposite ends thereof in overlying relation to opposite end faces of the outer race to capture the bearing axially in the bearing well.

10. A method of securing a sealed roller bearing having an inner race, an outer race and lubricated rolling elements disposed between the inner and outer races in a molded plastic housing member, comprising:

inserting the sealed bearing in a mold configured to form the housing member;

introducing hot, flowable plastics material into the mold and allowing the material to flow about the outer race of the sealed bearing to fix the sealed bearing in the resultant housing member; and

during molding, maintaining the temperature of the sealed roller bearing at a temperature below which the sealed bearing would be damaged by heat.

11. The method of claim 10 in which the outer race has an outer surface and opposite end faces, and wherein the plastics material flows about the outer surface and end faces during molding to circumferentially and axially encapsulate the outer race.

12. A method of remanufacturing spent alternators having a metallic drive-end (D.E.) frame, a stator secured to the D.E. frame, and a sealed bearing received in a bearing well of the D.E. frame and retained axially against removal by a spun-over lip of the D.E. frame overlying an outer race of the sealed bearing, said method comprising:

removing the stator and bearing from the metal D.E. frame of the spent alternator;

inserting a sealed bearing in a mold configured to form a plastics D.E. frame;

introducing hot, flowable plastics material into the mold and flowing the plastics material about the inserted bearing while maintaining the bearing at a temperature below which the bearing would be damaged from heat to mold the bearing in place in the resultant plastics D.E. frame; and

removing the plastics D.E. frame from the mold; and

while the plastics D.E. frame is still hot out of the mold, inserting a stator in the plastics D.E. frame and allowing the plastics D.E. frame to cool and constrict about the stator to secure the stator to the plastics D.E. frame.

13. A method of remanufacturing spent alternators having a drive-end (D.E.) frame molded of plastics material, a stator secured to the D.E. frame, and a sealed bearing secured to the frame, said method comprising:

fracturing the D.E. frame of the spent alternator to separate the stator and bearing from the D.E. frame;

introducing hot, flowable plastics material to a mold to form a new D.E. frame;

removing the new D.E. frame from the mold while the plastics material is still hot; and

before the new D.E. frame cools to ambient temperatures, inserting a stator in the new D.E. frame and allowing the plastics material to cool and constrict about the stator.

14. A housing assembly comprising:

a sealed bearing having an inner race, an outer race, and lubricated roller elements disposed between the inner and outer races;

a molded plastics housing body having a bearing well within which said sealed roller bearing is molded in place including an inner wall surface engaging an outer surface of said outer race, and axial restraining portions extending radially inwardly from said inner wall in overlying relation to axially opposite end faces of said outer race for restraining said bearing axially against removal from said bearing wall.

15. A housing assembly, comprising:

a first housing member fabricated of injection molded plastics material;

a second housing member joinable to said first housing member;

said first housing member having an end wall portion and an outer peripheral side wall portion extending from said end wall portion to provide a generally cup-shaped configuration to said first housing member;

a shaft opening formed in said end wall portion in radially inwardly spaced relation to said outer peripheral side wall portion;

a bearing well wall portion extending from said end wall portion to an upper end in surrounding relation to said shaft opening, said bearing wall portion having an inner wall surface spaced from and concentric with said shaft opening;

an annular end flange section of said end wall portion extending between said shaft opening and said inner wall surface of said bearing well wall portion and providing, together with said bearing well portion, a cup-shaped bearing well;

a bearing disposed in said bearing well, said bearing having an outer race engaging said inner wall surface of said bearing well wall portion and said annular end flange section of said end wall portion; and

an annular retaining flange portion molded as one piece with said bearing well wall portion of said first housing member and extending radially inwardly of said inner wall surface of said bearing well wall portion in overlying, confronting relation to said outer race of said bearing to retain said bearing against removal from said bearing well.

16. The housing assembly of claim 15 wherein said outer race of said bearing has a generally cylindrical outer surface and includes a plurality of recesses extending into said outer surface, said bearing well wall portion including interlocking retaining projections extending into said recesses in radially inwardly projecting relation to said inner wall surface of said bearing well wall portion.

17. The housing assembly of claim 16 wherein said recesses of said outer race comprise a series of grooves disposed transverse to a longitudinal axis of said shaft opening.

18. The housing assembly of claim 16 wherein said recesses comprises a plurality of crisscrossing grooves disposed transverse to a longitudinal axis of said shaft opening and transverse to a plane normal to said longitudinal axis.

19. The housing assembly of claim 18 wherein said crisscrossing grooves intersect one another.

20. The housing assembly of claim 18 wherein said interlocking retaining projections fill said grooves.

21. The housing assembly of claim 15 wherein said bearing includes an inner race supported for free rotation relative to said outer race.

22. The housing of claim 15 wherein said bearing comprises a sealed bearing.

23. The housing assembly of claim 22 wherein said sealed bearing includes an inner race spaced from said outer race, a plurality of bearing elements disposed in a space between said inner and outer races, and a seal extending between said inner and outer race and sealing said space from the external environment.

24. A method of making a housing assembly, comprising:

fabricating a first housing member;

fabricating a second housing member by injecting hot plastics material into a mold cavity and molding the plastics material around an outer race of a sealed bearing to secure the outer race to the second housing member while retaining relative rotational movement of an inner race of the bearing.

25. The method of claim 24, including forming recesses in an outer surface of the outer race and flowing the plastics material into the recesses during molding.

26. The method of claim 25 wherein the recesses are formed by forming a series of crisscrossing grooves in the outer surface and filling such grooves with the plastics material during molding.

27. The method of claim 24 including molding the plastics material around opposite ends of the outer race.

28. The method of claim 26 including spacing the plastics material from the inner race.

29. A housing of an electrical device, comprising:

a housing body molded of plastics material; and

a ground path of conductive material different than that of said plastics material molded in place and embedded in said plastics material.