The present invention relates to an electrically-operated mirror actuator assembly which is used in vehicles for remote adjustment of a reflective mirror element in a rearview mirror assembly, especially an exterior rearview mirror assembly.  More particularly, the present invention relates to the housing for the mirror actuator assembly in which weather seals and motor noise dampeners are integrally formed with the housing, preferably by injection molding. 
Today most adjustable exterior rearview mirror assemblies include a mirror actuator assembly.  The mirror actuator assembly is powered by a 12-volt supply from the vehicle or vehicle ignition system and is supported and housed in the mirror assembly casing.  The actuator assembly comprises an actuator housing and one or more motors with appropriate gearing, which are supported in the actuator housing.  Conventional actuator housings typically include upper and lower housing members, with the actuator motor and gearing supported in the lower housing member.  The actuator motor drives the gearing, which in turn drives a positioning member.  During operation, actuator motors tend to generate noise that can be heard by the operator and passengers of the vehicle.  Since the trend in automobile design is to reduce noise so that the operator and passengers can enjoy a peaceful ride, noise dampeners are employed to reduce the motor noise.  Heretofore, these noise dampeners have been manually inserted into and affixed to the housing; therefore, their installation is labor intensive, which increases the cost of the actuator assemblies. 
The positioning member of the actuator assembly is drivingly coupled to the gearing and projects through the upper housing member through openings formed in the housing to engage the back of a mirror element backing plate.  The mirror backing plate is pivotally mounted to the upper housing member by a ball mount or semi-spherical structure which engages a corresponding pivot structure provided on the upper housing member of the actuator assembly.  In this manner, the mirror element and mirror backing plate pivot as a unit about the pivot structure in response to the movement of the positioning member, which is driven to extend and withdraw in and out of the actuator housing by the actuator motor and gearing. 
Since actuator assemblies are used in exterior rearview mirror assemblies they are exposed to numerous elements, such as rain and road spray, which could adversely affect their operation and functionality.  Consequently, conventional actuators used in exterior rearview mirrors include weather seals, which are needed to seal the openings in the housing, for example, the openings in the upper housing through which the mirror positioning member extends and the connection between the upper and lower housing members.  These weather seals prevent moisture and debris, which are typically encountered during use of the vehicle, from entering the actuator housing.  The positioning member opening of the upper housing is typically sealed with a flexible boot.  Boots typically include a first open end engaging the upper housing member over the mirror positioning member opening and a second open end engaging the positioning member wherein the second open end moves in and out of the opening in the upper housing member in response to the movement of the positioning member.  These boots require manual installation and must be accurately seated on the upper housing member in order to assure proper sealing. 
Conventional perimeter or gasket seals comprise a die cut gasket which is positioned between the upper and lower housing members.  Die cut gaskets are labor intensive.  First, the gasket cutting is subject to tight tolerance control--otherwise, there may be fit-up problems in the assembly line.  Furthermore, they require careful alignment between the housing members to assure the integrity of the seal.  Heretofore, all these seals have required manual insertion into the mirror actuator assembly and careful alignment in their respective openings to assure proper sealing.  Hence, these seals add considerable cost to the manufacture and assembly process. 
In some actuators, the gasket seal is eliminated.  To eliminate the gasket seal, these actuator housings include a tongue and groove connection, with one of the upper and lower housing members including the groove, and the other member including the tongue.  However to achieve the desired sealing characteristics, the tongue requires a knife edge on the perimeter of the respective housing member.  These knife edge perimeters are difficult to tool and mold because the upper and lower housing members are subject to tight tolerance control--again, the need for proper fit-up in the assembly line. 
Consequently, there is a need for an actuator housing that requires fewer manual steps to assemble and yet provides seals to protect the actuator housing from the elements and, optionally, dampeners to reduce the motor noise characteristics of the actuator assembly.  Furthermore, there is a need for an actuator assembly that produces less noise.