The present invention relates to a motor structure and, more particularly, to a motor structure with improved positioning device for positioning a stator and a bearing of the motor structure.
A need exists for a motor structure with a positioning device to reliably position the stator relative to the bearing.
The present invention solves this need and other problems in the field of motor stator positioning devices by providing, in a preferred form, a motor structure includes a housing having a shaft tube receiving a bearing. The shaft tube includes a positioning section on an outer periphery thereof. A rotor includes a shaft rotatably extending through the bearing. A stator is mounted around the shaft tube and includes an upper bobbin, a lower bobbin, a plurality of silicon steel plates sandwiched between the upper and lower bobbins, and a winding wound around the plurality of silicon steel plates. The upper bobbin includes an abutting portion, and the lower bobbin includes an engaging portion. The positioning section of the shaft tube provides the engaging portion of the lower bobbin with an axial supporting force along a longitudinal axis of the shaft tube to position the stator in a fixed axial position relative to the bearing along the longitudinal axis of the shaft tube. And the abutting portion of the upper bobbin abuts the bearing to prevent the bearing from disengaging from the shaft tube.
In an example, the shaft tube includes an upper section and a lower section having an outer diameter larger than that of the upper section. An annular shoulder is formed between the upper and lower sections and forms the positioning section. The engaging portion of the lower bobbin includes an annular flange on an inner periphery thereof. The annular flange rests on and is positioned by the annular shoulder to position the stator in the fixed axial position relative to the bearing.
In another example, the positioning section of shaft tube includes a plurality of annularly spaced blocks on the outer periphery thereof, and the engaging portion of the lower bobbin includes an annular flange on an inner periphery thereof. The annular flange rests on and is positioned by the blocks to position the stator in the fixed axial position relative to the bearing.
In a further example, the positioning section of shaft tube includes a plurality of annularly spaced protrusions on the outer periphery thereof, and the engaging portion of the lower bobbin includes an annular groove on an inner periphery thereof. The protrusions are engaged in the annular groove to position the stator in the fixed axial position relative to the bearing.
In still another example, the positioning section of the shaft tube includes a plurality of annularly spaced ribs extending in a direction parallel to the longitudinal axis of the shaft tube. Each rib has a top face spaced from a top edge of the shaft tube. The engaging portion of the lower bobbin includes an annular flange on an inner periphery thereof. The annular flange rests on and is positioned by the top faces of the ribs to position the stator in the fixed axial position relative to the bearing. The outer periphery of the shaft tube further includes a limiting rib extending between and spaced from two of the ribs adjacent to each other. The limiting rib has an upper end extending to the top edge of the shaft tube. The annular flange of the lower bobbin includes a through-hole through which the limiting rib extends, preventing rotation of the stator. The stator includes a limiting groove in an inner periphery thereof and aligned with the through-hole for receiving and positioning the limiting rib.
The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings.
The illustrative embodiments may best be described by reference to the accompanying drawings where:
All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the Figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiment will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood.
Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “lower”, “upper”, “end”, “portion”, “section”, “longitudinal”, “axial”, “annular”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the invention.
A motor structure of a first embodiment according to the preferred teachings of the present invention is shown in
Rotor 20 includes a shaft 21 in a central portion thereof. Shaft 21 is rotatably extended through bearing 22. Thus, rotor 20 can rotate on top of housing 10.
Stator 30 includes an assembling hole 31 so as to allow stator 30 to be mounted around shaft tube 11. Preferably, stator 30 is coupled to the outer periphery of shaft tube 11 by tight coupling, bonding, or other suitable ways to reliably fix stator 30 on shaft tube 11. Stator 30 includes upper and lower bobbins 32 and 33, a plurality of silicon steel plates 34 sandwiched between upper and lower bobbins 32 and 33, and a winding 35 wound around silicon steel plates 34. Upper bobbin 32 includes an annular wall 321 extending upward from an upper end thereof to provide a shielding wall preventing dust from entering an interior of shaft tube 11 after stator 30 is coupled with shaft tube 11. An abutting portion 322 is formed on an inner periphery of annular wall 321. Abutting portion 322 can be in the form of a plurality of annularly spaced plates or an annular ring to abut bearing 12, preventing disengagement of bearing 12 from shaft tube 11. Lower bobbin 33 includes an engaging portion 36 in the most preferred form shown as an annular flange 361 on an inner periphery of lower bobbin 33. Annular flange 361 rests on and is positioned by annular shoulder 151. Namely, annular shoulder 151 of shaft tube 11 provides annular flange 361 of lower bobbin 33 with an axial supporting force along a longitudinal axis of shaft tube 11. Thus, stator 30 is positioned in a fixed axial position relative to bearing 12 along the longitudinal axis of shaft tube 11 so that stator 30 is in an appropriate assembling position neither too high nor too low relative to bearing 12. It assures abutting portion 322 of upper bobbin 32 to abut bearing 12, so as to prevent bearing 12 from disengaging from shaft tube 11.
Namely, ribs 154 of shaft tube 11 provide annular flange 364 of lower bobbin 33 with an axial supporting force along the longitudinal axis of shaft tube 11. Thus, stator 30 is positioned in the fixed axial position relative to bearing 12 with abutting portion 322 abutting bearing 12 to prevent bearing 12 from disengaging from shaft tube 11. Limiting rib 155 prevents stator 30 from rotating while mounting stator 30 around shaft tube 11, improving assembling convenience.
Due to the specific location of positioning section 15 on the outer periphery of shaft tube 11, engaging portion 36 of stator 30 is coupled with and positioned by positioning section 15 so that stator 30 is in the fixed axial position relative to bearing 12 with abutting portion 322 of upper bobbin 32 abutting bearing 12. Thus, loosening of bearing 12 due to higher assembling position of stator 30 and breakage of abutting portion 322 due to lower assembling position of stator 30 are avoided. Assembling convenience and reliable assembly are, thus, provided.
Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.
This application is a continuation-in-part application of U.S. patent Ser. No. 12/155,959, filed on Jun. 12, 2008.
Number | Date | Country | |
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Parent | 12155959 | Jun 2008 | US |
Child | 12174687 | US |