Patent Application
20060028088
The present invention generally relates to the field of motors and more particularly to a bearing mounting having an integrated brush holding capability and direct support for a stator, or field magnet, wire for universal motors.
Motors and in particular, universal motors proliferate everyday life in modern societies. Universal motors are particularly effective for utilization in devices in which size and weight are of concern. Power tools such as portable compressors, hand power tools (e.g., drills, circular saws, and the like), and the like typically implement universal motors. Due to the extensive use of motors in everyday situations, the efficient manufacture of these devices is critical. Assembly of the various motor components may require significant labor/expense to assemble. For example, the assembly of the shaft/brushes in a motor may require that the brushes be assembled prior to the motor/shaft assembly being incorporated into the housing. Additionally, brushes are assembled by inserting the components through an interior recess of a cap or housing. In a further example, the brushes may have to be positioned in an “open” or non-contacting position for connection of the motor shaft/commutator/rotor core into the mounting. Manufacturing a motor in this fashion may be time consuming as personnel are required to manipulate the components to ensure proper alignment. This may increase labor and the overall time required to assemble the motor.
Furthermore, current motors may require a significant number of electrical terminals (connections) to make the motor operable. Electrical connecting lead wires to the brushes in a motor may be time consuming and require the assembly of multiple components as part of motor assembly. In some instances, several wire ties are implemented to secure the lead wires to the main body of the brush. These procedures may decrease overall motor manufacturing capability and require personnel having high levels of dexterity and skill, as well as increasing the overall cost of the motor due to the inclusion of numerous terminals.
Therefore, it would be desirable to provide a motor mounting, a motor and a simplified and efficient method of manufacture.
Accordingly, the present invention is directed to a motor mounting, motor, and a method of manufacture for simplified motor assembly.
In an aspect of the invention, a mounting for an electrical motor is described. The mounting may be formed of electrically insulating material and includes an end recess for accepting a bearing for supporting a received rotor shaft. The mounting includes a brush assembly receiving structure for accepting a brush assembly such as in a tool-less snap-fit securing arrangement. The motor mounting is configured so a brush assembly may be received from an exterior direction. In the foregoing instance, the mounting is configured such that a received brush assembly may be accepted from the exterior of the mounting and directed generally toward an interior recess constructed to accept the rotor. In a particular embodiment, a cleat may be formed on the housing for mechanically securing a field or stator lead wire.
In an additional aspect of the invention, a motor including a motor mounting and brush assembly is disclosed. The mounting includes a bearing recess for accepting a bearing for supporting a rotor shaft included in a rotor for being accepted in an at least partial recess formed by the mounting. The mounting further includes a brush aperture which extends from an outer surface of the mounting toward the at least partial recess for accepting the rotor in order for the brush assembly to be inserted from the outer surface. The brush assembly and mounting being configured to receive the brush assembly in a frictionally secured relationship.
In a further aspect, a method of manufacturing a motor includes the steps of securing a rotor shaft bearing to a motor mounting, inserting a rotor shaft included as part of the rotor into the bearing and assembling a brush assembly from the exterior of the mounting by inserting the brush toward the rotor.
It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention.
The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which:
Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. It is to be appreciated that generally corresponding structures are provided with corresponding reference numbers.
Referring to
In the present embodiment, the mounting 102 is formed of a molded plastic. In additional embodiments, the mounting may be formed from a phenolic, a polymer/glass reinforced polymer, such as a phenolic with glass fill, or the like. Preferably, the mounting 102 is formed of an electrically insulating type material or a non-conductive material. Forming the mounting 102 from an insulating material may permit the implementation of lead wires which are not insulated. For example, a non-insulated or bare lead wire from the stator windings connected to a brush shunt may promote efficient assembly as insulation removal, or stripping of the wire, or utilization of a partially insulated wire is not required.
With reference to
In the present embodiment, support brackets 118 (one is referenced) extend outwardly from the end portion for securing the mounting in a motor housing, or the like. In further embodiments, the mounting 102 may be shaped as a partial cap or generally hollow cylinder for at least partially containing the rotor 116. For example, the mounting 102 may at least partially enclose the commutator 126, and/or the rotor winding 128. In the current example, the mounting including the end portion and support brackets are unitary. The support brackets 118 may extend generally away from the portion including the bearing recess, with the brackets directed so as to form a cap-like structure or partial enclosure forming a central recess 146 for encompassing at least a portion of the rotor 116. For example, the terminal portions of the support brackets are substantially parallel with a primary axis extending through the motor shaft 112 in order to accommodate stator components, promote efficient molding, and the like. Thus, the stator windings, or field windings, are generally coaxially disposed with respect to the rotor. For example, the wire windings forming the stator, or field, are wound and secured to the brackets by a plastic tie (i.e., a friction lock strip). The stator winding 122 may be secured to the interior surface of the bracket 118 to provide the desired gap between the stator and the rotor. The mounting 102 may be shaped to permit airflow over heat generating portions such as by including airflow openings in a support bracket. Additionally, a cross member 120 may be included in the bracket 118 for securing the stator components thereto, via a mechanical fastener, or the like. Those of skill in the art will appreciate the mounting/support brackets may be shaped as desired based on design preferences, to accommodate the functional requirements of the motor, to conform to an exterior motor housing, or the like. It is the intention of this application to encompass and include such variation.
Referring now to
In an aspect of the invention, the mounting 102 defines a brush receiving structure for retaining a brush assembly 108 to the mounting. Two brush assemblies are illustrated, with the brush assemblies being substantially similar. Those of skill in the art will appreciate that multiple brush holders may be formed in the bearing support and be disposed (e.g., angular orientation or the like) to promote efficiency or other motor design factors. Preferably, the brush receiving structure permits assembly from an exterior of the mounting or away from a central 146, at least partial recess, for receiving a rotor and stator components. In this manner, the rotor may be preassembled to the mounting prior to the brush assembly being accepted to the mounting. Such configuration avoids the difficulties previously experienced. The mounting/brush assembly of the present invention may minimize the number of terminals required for assembly as multiple connections required for assembly through the central 146, or rotor, recess may be avoided.
For example, the mounting includes a through aperture 140 (which extends radially away from the commutator 126, included in the received rotor 116) for accepting a brush assembly 108 including a brush housing 134. In the present embodiment, the aperture 108 has a generally rectangular cross-section. In additional examples, a through aperture is shaped as desired. In further embodiments, other suitable mounting structures include interconnecting grooves/rails formed on the mounting 102/brush assembly 108 and the like for securing the brush assembly are implemented. A tool-less mechanical securing mechanism may be included on the mounting 102/brush housing 134. For instance, the brush assembly is retained by a snap-fit device. With particular reference to
A biasing device such as a roll spring 132 may be included in the brush assembly 108 for directing the brush 130 into contact with the commutator 126 contacts. For example, the roll spring 132 includes an end tab, which engages with the brush housing adjacent the contact portion of the brush 130 and may extend in a channel to engage a side of the brush 130 generally opposite the contact portion. The foregoing arrangement permits efficient brush removal for replacement without having to remove the brush assembly from the mounting 102. It is to be appreciated that a wide variety of biasing devices may be implemented. In alternative embodiments, a biasing device is implemented to bias the brush and brush housing which are fixedly secured. Preferably, the mounting is configured with integrated brush holders to allow for the insertion and retention of the motor brushes in proper orientation with respect to the motor shaft/commutator, such as for utilization in a universal motor.
Referring to
It is believed that the present invention and many of its attendant advantages will be understood by the forgoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.
The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 60/599,405, entitled: Bearing Support for Motors, filed on Aug. 6, 2004, which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60599405 | Aug 2004 | US |
