BRUSH HOLDER FOR DYNAMOELECTRIC MACHINE

• US 3,745,393 A
• Filed: 04/28/1972
• Issued: 07/10/1973
• Est. Priority Date: 04/28/1972
• Status: Expired due to Term

• Current Assignee: James A. Spors
• Original Assignee: James A. Spors
• Inventors: Spors, James A.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/248,447
• Time in Patent Office: 438 Days
• Field of Search: 310/239,242,247
• US Class Current: 310/239
• CPC Class Codes: H02K 5/148 Slidably supported brushes

Abstract

A brush holder for a dynamoelectric machine comprises a molded carrier and a stamped washer-like member. The carrier is annular and has radially elongated brush receiving recesses, each of which opens radially inwardly and also opens unrestrictedly to one axial surface of the carrier so that it can be molded without need for movable cores. The washer-like member flatwise overlies said surface of the carrier, closing said recesses. Screws fasten the carrier and washer-like member into an end bell and also serve as terminals for grounded brush leads.

Claims

1. Means for mounting brushes of a dynamoelectric machine having a rotor with a shaft and having a generally cup-shaped end bell that concentrically supports a bearing for the shaft and comprises an enclosure for the brushes and the brush mounting means, said brush mOunting means comprising:

A. a substantially annular brush carrier of insulating material received in the end bell and closely embraced by its circumferential wall to be held concentric therewith, said carrier having circumferentially spaced apart radially elongated recesses, each defined by 1. opposed radially extending and circumferentially facing surface portions on the carrier between which a brush is lengthwise slidably confined against circumferential displacement, and 2. a wall portion near one axial side of the carrier that connects portions of the carrier at opposite sides of the recess and confines the brush against axial motion in one direction, each of said recesses opening radially inwardly relative to the carrier and also opening unrestrictedly to the other axial side of the carrier so that the carrier can be molded without the need for movable coring;

B. a flat washer-like member of insulating material in the end bell, closely embraced by said circumferential wall to be confined against edgewise motion thereby and confined in flatwise overlying relationship to said other axial side of the carrier to close the open axial side of each recess and confine a brush therein to lengthwise sliding motion; and

C. means securing the carrier and the washer-like member against rotational and axial displacement relative to the end bell.

2. a wall portion near one axial side of the carrier that connects portions of the carrier at opposite sides of the recess and confines the brush against axial motion in one direction, each of said recesses opening radially inwardly relative to the carrier and also opening unrestrictedly to the other axial side of the carrier so that the carrier can be molded without the need for movable coring;

B. a flat washer-like member of insulating material in the end bell, closely embraced by said circumferential wall to be confined against edgewise motion thereby and confined in flatwise overlying relationship to said other axial side of the carrier to close the open axial side of each recess and confine a brush therein to lengthwise sliding motion; and

C. means securing the carrier and the washer-like member against rotational and axial displacement relative to the end bell.

3. The dynamoelectric machine of claim 2, further characterized by:

E. said means spacing said washer-like member axially inwardly from the bearing comprising a plurality of circumferentially spaced, radially extending lands on the inner surface of the end bell end wall.

4. The dynamoelectric machine of claim 3, further characterized by said means securing the carrier and the washer-like member comprising:

F. a plurality of bosses projecting axially inwardly from the end wall of the end bell through registering holes in the washer-like member and the carrier, the holes in the carrier being spaced from said recess-defining portions thereof;

G. a screw threaded into each of said bosses from the axially inner end thereof; and

H. a wave washer surrounding each boss and co-operating with the head of the screw therein to confine the washer-like member and the carrier axially against one another and said lands on the end bell end wall.

5. The dynamoelectric machine of claim 4, further characterized by:

I. each of said recesses in the carrier being closed at its radially outer end by another wall portion of the carrier that extends circumferentially relative thereto;

J. a compression spring in each recess, reacting between said other wall portion and the brush in the recess to bias the brush radially inwardly; and

K. each of said first mentioned wall portions having a slot that is elongated radially relative to the carrier and which opens radially toward the center of the carrier, through which slot a conductor lead extends that is connected with the brush in the recess.

6. The dynamoelectric machine of claim 5, further characterized by:

L. at least one conductor lead being connected with one of said screws to ground its brush to the end bell.

7. The dynamoelectric machine of claim 6, further characterized by:

M. another screw extending through the circumferential wall of the end bell, with its head at the interior thereof, to provide a terminal to which a supply lead can be connected;

N. means insulating said other screw from the end bell; and

O. means connecting at least one other of the conductor leads to said other screw.

8. Means for mounting brushes of a dynamoelectric machine having a rotor with a shaft and having a cup-shaped end bell that concentrically supports a bearing for the shaft and comprises an enclosure for the brushes and the brush mounting means, said brush mounting means comprising:

A. a substantially annular brush carrier of insulating material having circumferentially spaced radially elongated grooves therein that open radially inwardly and also open unrestrictedly to only one axial side of the carrier, each of said grooves being of a size to receive a brush and a compression spring by which the brush is biased radially inwardly, and said carrier having a circumferentially extending wall portion across the radially outer end of each of said grooves against which the spring can react and other wall portions that define the bottoms of said grooves and guidingly confine the brushes against displacement toward the other axial side of the carrier;

B. a flat washer-like member overlying the first mentioned axial side of the carrier to close said grooves at said side of the carrier and thereby cooperate with said other wall portions to confine a brush in each groove to motion lengthwise of it; and

C. cooperating means on the carrier, the washer-like member and the end bell for holding the carrier and washer-like member concentric to the end bell and with the washer-like member normal to the axis of the bearing and flatwise contiguous to said side of the carrier.