Optical: systems and elements – Mirror – With support
Reexamination Certificate
1999-09-29
2001-06-05
Sikder, Mohammad (Department: 2872)
Optical: systems and elements
Mirror
With support
C359S871000, C359S872000, C359S841000
Reexamination Certificate
active
06243218
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to exteriorly mounted rearview mirrors for vehicles and, more particularly, to power folding exterior rearview mirrors which fold between an operable position and a folded position in response to an electronic actuator, and to motors for positioning the field of view of exterior rearview mirror reflectors.
Exterior rearview mirrors are located on one or both sides of a vehicle to provide a vehicle operator with a view rearward and to either side of the vehicle. Many vehicles provide rearview mirrors which are foldable between an operable position, where the rearview mirror extends outwardly from the side of the vehicle, and a folded position, where the rearview mirror is folded alongside the vehicle. Conventional folding mirrors typically include a folding portion and a substantially fixed, non-folding portion, which is mounted adjacent to a side or side window of the vehicle. The folding portion pivots about a pivot axis defined by a pivot spindle, which is typically secured to the non-folding portion. While many of these folding mirrors may be manually folded between the operable and folded positions, or may move towards the folded position if impacted such as in breakaway mirrors, many vehicles now include power folding mirrors to facilitate pivoting of the mirror housing via a manual control within the vehicle or in response to an electronic signal.
Power folding mirrors and electrically operated mirror reflector positioning power packs typically include an electronic actuator, such as a conventional motor with a rotating output shaft. Moreover, powerfold actuators and mirror reflector positioning power packs/actuators commercially used utilize conventional armature motors which consist typically of an armature that is surrounded by a coil or coils (typically consisting of multi-wire windings) passing electrical current. The shaft of the motor turns by the actuator responding to electromagnetic fields generated by passage of electricity through the coil(s) of the motor. The need to accommodate at least an armature and coil(s) in the motor housing can lead to a relatively large package that in turn presents difficulties accommodating the actuator in the restricted space available in exterior rearview mirror assemblies. Thus, there is a need for a contact motor for such applications.
In powerfold mirror actuator applications, the motor is operable to rotate the output shaft, which engages multiple gears or worm drives which further engage the pivot spindle on the non-folding portion of the mirror. Rotation of the output shaft causes relative rotation between the motor and the spindle to thus pivot the mirror housing about the spindle. Such standard motors operate at relatively high RPMs and have a low output torque. Accordingly, multiple gears are required between the output shaft and the pivot spindle in order to generate enough torque to move the mirror about the pivot spindle. This results in multiple moving parts within the system, which may further result in increased weight and reliability concerns with respect to the mirror system.
Because there is relative movement between the folding portion and non-folding portion of the mirror as the mirror is folded inwardly toward or outwardly from the vehicle, difficulties may arise in routing an electronic cable or wiring from within the vehicle or door to the actuator positioned within the folding portion of the mirror assembly. Typically, corresponding openings or slots must be formed through one or both of the folding portion and the non-folding portion of the mirror assembly. This allows the cable to be routed from the non-folding portion into the folding portion such that the cable may move relative to one or both portions as the mirror is folded, with minimal interference with the movement of the folding portion of the mirror.
SUMMARY OF THE INVENTION
The present invention is intended to provide a compact, efficient non-armature motor drive for exterior rearview mirror assemblies, such as for a powerfold mirror actuator or for a mirror reflector positioning actuator. The mirror actuator does not require multiple gears or the like, and thus is highly efficient and reliable.
According to an aspect of the present invention, an exterior rearview mirror assembly for a vehicle comprises a movable portion and a non-movable portion, and an actuator comprising a non-armature electrical motor operable to move the movable portion relative to the non-movable portion. Preferably, the non-armature electrical motor comprises an ultrasonic motor and, most preferably, a traveling wave ultrasonic motor. In one form, the mirror assembly comprises a power folding mirror assembly. The movable portion comprises a mirror housing and the non-movable portion comprises a mirror mount. The actuator is operable to pivot the mirror housing relative to the mirror mount between an operable position and a folded position. In another form, the movable portion comprises a reflective element and the non-movable portion comprises a mirror housing. The actuator is operable to pivot the reflective element relative to the mirror housing.
According to another aspect of the present invention, an exterior mirror assembly for a vehicle comprises a mirror system comprising a folding portion and a non-folding portion and a mirror actuator operable to pivot the folding portion relative to the non-folding portion. The folding portion comprises a reflective element and the non-folding portion is adapted to mount to the vehicle. The folding portion is pivotable relative to the non-folding portion between an operating position and a folded position. The mirror actuator comprises a non-armature motor, preferably an ultrasonic motor. Most preferably, the mirror actuator comprises a traveling wave ultrasonic motor, which is operable to pivot a rotating member mounted to the folding portion of the mirror in response to a vibrational wave produced in a piezo-electric element mounted to the non-folding portion. The vibrational wave is produced by applying a phased voltage to the piezo-electric element, which may be fixedly secured to an elastic stator. A resultant flexural vibration of the stator produced by the piezo-electric element frictionally drives and rotates the rotating member relative to the piezo-electric element. In one form, a passageway is formed through a shaft of the rotating member. A vehicle wiring may be connected to at least one electronic mirror accessory via the passageway.
According to another aspect of the present invention, a reflective element positioning actuator comprises a non-armature electrical motor for adjustably positioning a reflective element of a mirror relative to a housing of the mirror. The non-armature electrical positioning actuator preferably comprises an ultrasonic motor and, most preferably, a linear traveling wave ultrasonic motor. The ultrasonic positioning actuator comprises a base, at least two piezo-electric strips, and a movable member. The base provides a phased voltage to the piezo-electric strips. The piezo-electric strips extend and retract as a traveling wave along a length of the strips in response to the phased voltage. The piezo-electric strips extend to impact the movable member to cause linear movement of the movable member in a direction generally opposite to the traveling wave. The movable member is movable to adjust a position of the reflective element relative to the housing of the mirror.
These and other objects, advantages, purposes and features of this invention will become apparent upon review of the following specification in conjunction with the drawings.
REFERENCES:
patent: 5210651 (1993-05-01), Shibuya et al.
patent: 5424898 (1995-06-01), Larson et al.
patent: 5579178 (1996-11-01), Mochizuki
patent: 5659423 (1997-08-01), Schierbeek et al.
patent: 5670935 (1997-09-01), Schofield et al.
patent: 5796176 (1998-08-01), Kramer et al.
patent: 5900999 (1999-05-01), Huizenga et al.
Figure A: Design Picture of an Allied Signal Aerospace Traveli
Donnelly Corporation
Sikder Mohammad
Van Dyke Gardner, Linn & Burkhart, LLP
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