This invention relates to controlling endplay and alignment of a shaft of an electric motor.
In conventional motors, one of a number of endplates is selected to take-up a gap between an end of a shaft and a gear housing. The endplay plates vary in thickness by 0.1 mm. Visual inspection is done to optimize the gap and the correct thickness endplay plate is picked up via automation to meet the constant endplay plate gap of between 0.02–0.20 mm. Disadvantages of this configuration include the requirement of providing numerous parts (endplay plates) with different thickness. In addition, a constant process check is needed to select the optimum endplay plate 10 based on the gap between the end of the shaft 12 and endplay plate 10. Furthermore, with these configurations, a separate cylindrical bushing is needed to locate the shaft. Thus, conventional motors require numerous parts with regard to controlling shaft location and endplay.
Thus, there is a need to reduce the number of parts for controlling shaft location and endplay.
An object of the present invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is obtained by providing a bushing structure constructed and arranged to be operatively associated with a shaft of an electric motor. The motor has a housing including a generally elliptical recess therein defined along an axis of the shaft. The bushing structure includes a generally cylindrical bushing member constructed and arranged to engage an end of the shaft so as to locate the shaft with respect to the housing and to prevent lockup of the motor. An endplay member is associated with the bushing member and with the end of the shaft. The endplay member includes a spherical portion constructed and arranged to be received in the elliptical recess so as to control endplay of the shaft.
In accordance with another aspect of the invention, an electric motor includes a housing and a shaft mounted for rotation with respect to the housing. The housing includes a generally elliptical recess therein. The recess is disposed generally adjacent to an end of the shaft. A generally cylindrical bushing member is engaged with an end of the shaft so as to locate the shaft with respect to the housing and to prevent lockup of the motor. An endplay member is associated with the end of the shaft and includes a spherical portion received in the elliptical recess so as to control endplay of the shaft.
Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.
The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which:
With reference to
The bushing structure 10 is shown in
The end of the shaft 24 is received in the recess 14 of the bushing member 12 such that the bushing member 12 locates the shaft and prevents lock up of the motor. The assembly force from the shaft 24 will force the endplay member 20 into the proper location for automatic adjustment of the end gap between the shaft 24 and gearhousing 30. Thus, the single component of the bushing structure 10 functions to locate the shaft 24 and controls endplay of the shaft instead of the many components needed for these functions in the conventional bushing-endplate configuration as described above. Thus, the invention provides cost-savings, reduction of parts, and ease of assembly.
Thus, the embodiments of the invention reduce the number of parts for controlling shaft location and endplay of a bi-directional motor.
The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.
This application is based on U.S. Provisional Application No. 60/520,015, filed on Nov. 14, 2003 and claims the benefit thereof for priority purposes.
Number | Name | Date | Kind |
---|---|---|---|
4900960 | Becker et al. | Feb 1990 | A |
5144738 | Oyafuso | Sep 1992 | A |
5213000 | Saya et al. | May 1993 | A |
5747911 | Kikly | May 1998 | A |
5811903 | Ueno et al. | Sep 1998 | A |
6541886 | Mayumi | Apr 2003 | B2 |
6886678 | Acosta | May 2005 | B2 |
20050081667 | Oh et al. | Apr 2005 | A1 |
Number | Date | Country |
---|---|---|
4128110 | Feb 1993 | DE |
19513970 | Oct 1996 | DE |
19537503 | Mar 1997 | DE |
0998013 | May 2000 | EP |
1122863 | Aug 2001 | EP |
2016213 | Sep 1979 | GB |
10066296 | Mar 1998 | JP |
Number | Date | Country | |
---|---|---|---|
20050104463 A1 | May 2005 | US |
Number | Date | Country | |
---|---|---|---|
60520015 | Nov 2003 | US |