The present invention is directed generally to linear brushless DC motors, and in particular to a composite armature assembly for linear brushless DC motors.
A typical linear brushless motor of a rectangular configuration consists essentially of two parts: an armature assembly and a field assembly separated from each other by a small air gap.
An armature assembly, in turn, consists of a stack 10 of laminations with a three-phase winding positioned in its slots 12. Such a stack 10 is shown in
Slot openings 14 for the armature assembly are normally selected to be as small as possible to minimize cogging (detent) forces.
Additionally, in order to attach an armature assembly to a mechanical structure, the top surface 16 of the stack 10 should have drilled and tapped holes. Since laminations are not suitable for such holes, locking wedges 18 with mounting holes are provided, as shown in FIG. 1. Once the laminations are punched with the slots 20 for these locking wedges 18, the distance between locking wedges becomes fixed and cannot be changed without re-tooling the punch for the laminations.
It is therefore desirable to have an armature assembly design which facilitates winding of coils, while also minimizing cogging forces. It is also desirable to have an armature assembly design in which attachment to mechanical structures is simplified yet flexible.
The above and other desirable features are provided by the present invention of an armature assembly design comprising a base portion, a plurality of teeth extending from the base portion and about which the windings can be positioned, and in which the plurality of teeth are spaced apart from each other to define slot openings at ends of and between adjacent teeth, and magnetic material shaped and positionable to enclose one or more of the slot openings between adjacent teeth.
In another embodiment of the armature assembly of the present invention includes a base portion, a plurality of teeth extending from the base portion and about which windings can be positioned, and magnetic material shaped to be positioned upon and extend beyond outer edges of the base portion.
In a further embodiment of the present invention, an armature assembly includes a base portion, a plurality of teeth extending from the base portion and about which windings can be positioned, and in which the plurality of teeth are spaced apart from each other so as to define slot openings at ends of and between adjacent teeth, and magnetic material in the shape of wedges which are fitted into notches formed in the adjacent teeth to enclose the slot openings between adjacent teeth.
The design goals and features of the present invention include the following:
These and other features and advantages of the present invention will be more readily understood upon consideration of the detailed description and accompanying drawings.
Referring now to
According to the present invention, the top portion 108 of each tooth 102 has two additional notches 110, as can be seen in
According to a further embodiment of the present invention, illustrated in
This preferred dovetail arrangement is further illustrated in FIG. 5B. At the ends of stack 100 it can be seen that the base portion 106 has a surface which is angled outwardly in a direction toward the outer surface of base portion 106. It can also be seen that the ends of mounting bracket 120 have portions 122 and 124 which extend downwardly in the direction of teeth 102, and which have inner surfaces which are shaped to be compliments of the ends of base portion 106. In particular, the inner surfaces of portions 122 and 124 flare inwardly so that portions 122 and 124 capture the outwardly flared ends of base portion 106. While a dovetail arrangement has been disclosed as a preferred arrangement, it is to be understood that other arrangements can be used to position mounting bracket 120 on base portion 106 of stack assembly 100 within the spirit of the present invention.
Since not all of the back iron (base 106 and mounting bracket 120) is laminated in the embodiment of the invention shown in
With the configuration of the mounting bracket of the present invention there is no need for retooling of a lamination punch in order to accommodate changes in distance between mounting holes, and mounting hole configurations can be changed by replacing a single bracket instead of the multiple wedges of the prior art.
While a dovetail arrangement has been disclosed as a preferred arrangement, it is to be understood that other arrangements can be used to position wedge 112 between adjacent teeth 102 within the spirit of the present invention.
The terms and expressions which have been employed herein are intended as terms of description and not of limitation, and there is no intent in the use of such terms and expressions of excluding equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible within the scope of the invention claimed.
The present application claims priority under 35 U.S.C. §119(e) from provisional to application No. 60/282,546, filed Apr. 9, 2001.
Number | Name | Date | Kind |
---|---|---|---|
3746899 | Eastham | Jul 1973 | A |
3770995 | Eastham et al. | Nov 1973 | A |
4049983 | Attwood et al. | Sep 1977 | A |
4107558 | Brown | Aug 1978 | A |
4131812 | English | Dec 1978 | A |
4392073 | Rosenberry, Jr. | Jul 1983 | A |
4642493 | Wallace | Feb 1987 | A |
4665329 | Raschbichler | May 1987 | A |
RE32654 | Jackson | Apr 1988 | E |
4793263 | Basic et al. | Dec 1988 | A |
5128569 | Gladish | Jul 1992 | A |
5191246 | Roxborough | Mar 1993 | A |
5252877 | Sawa et al. | Oct 1993 | A |
5300846 | Miller | Apr 1994 | A |
5864187 | Gonzalez | Jan 1999 | A |
6433446 | Sedgewick et al. | Aug 2002 | B1 |
Number | Date | Country |
---|---|---|
4040116 | Jun 1992 | DE |
233838 | May 1925 | GB |
4-125054 | Apr 1992 | JP |
05-83924 | Apr 1993 | JP |
10-323012 | Dec 1998 | JP |
2000-308328 | Nov 2000 | JP |
Number | Date | Country | |
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20020145358 A1 | Oct 2002 | US |
Number | Date | Country | |
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60282546 | Apr 2001 | US |