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US 5,852,352 AGranted
Reduced speed growth in windshield wiper motor
AssigneeITT Automotive Electrical Systems, Inc.
InventorJohn Riden Suriano
Life of this patent
Estimating the term…
Abstract
In an ordinary DC motor in a windshield wiper, operating speed tends to increase as the motor brushes become seated. The invention counteracts this tendency by providing a brush geometry which causes the effective angular position of a brush to change during seating. The change is in a direction which tends to reduce speed.
Claims8
An electric motor in which brush seating occurs, comprising:
- a) brush means which
- i) causes motor speed to increase during early stages of brush seating;
- and
- ii) causes motor speed to decrease during later stages of brush seating.
1 more element
An electric motor, comprising:
- a) a commutator;
- b) brush means, which
- i) contacts the commutator, and
- ii) experiences brush seating as the motor operates, which causes
- A) motor speed to increase during initial stages of brush seating;
- B) motor speed to peak at about 40 percent of brush seating, at a peak speed of about 104.2 percent, or less, of motor speed at an initial brush seating, and
- C) motor speed to decrease after peaking, to a motor speed at full brush seating of about 102.3 percent, or less, of motor speed at initial brush seating.
4 more elements
An electric motor, comprising:
- a) a commutator;
- b) a brush
- i) which contacts the commutator at a contact surface,
- A) of length 2.times.ALPHA, and
- B) which is centered at a point which defines an effective brush angle, BETA;
- wherein ALPHA is one-half the length of said contact surface and BETA defines said effective brush angles;
- ii) which wears during operation of the motor, causing ALPHA to increase, thereby tending to cause motor speed to change;
- and
- iii) in which the wear causes BETA to change in a manner which compensates for the change in ALPHA, thereby opposing the change in motor speed.
6 more elements
Dependencies are inferred from the claim text.