Vibration noise suppressive rain sensor for a wiper control system

A rain sensor for an automotive wiper control system, comprising:

• a sensor housing;
• a vibrator with a sensor surface onto which rain drops can impinge and suspended in said sensor housing for vibration in response to the impact of rain drops onto the sensor surface, the resonant frequency of said vibrator being in a range outside of the vibration frequency range within which vibrations may be transmitted through the vehicle body;
• means for converting the vibrator vibrations into electric signals which vary according to the variation of the vibrator vibrations;
• wherein the resonant frequency of the vibrator is higher than the audible frequency range;
• and
• wherein said vibrator is of a generally discshaped configuration with a projecting rib concentric to and inside the circumferential edge of said vibrator, said rib defining the resonant frequency of the vibrator.

A rain sensor for an automotive wiper control system, comprising:

• a sensor housing;
• a vibrator with a sensor surface onto which rain drops can impinge and suspended in said sensor housing for vibration in response to the impact of rain drops onto the sensor surface, the resonant frequency of said vibrator being in a range outside of the vibration frequency range within which vibrations may be transmitted through the vehicle body;
• means for converting the vibrator vibrations into electric signals which vary according to the variation of the vibrator vibrations;
• wherein the resonant frequency of the vibrator is higher than the audible frequency range;
• and
• wherein said vibrator is of a generally discshaped configuration with a rib projecting from one surface of said vibrator for defining the resonant frequency of said vibrator outside of the audible frequency range.

A rain sensor for an automotive wiper control system, having a sensor surface exposed outside at a position adjacent a front windshield and adapted to produce a sensor signal representative of a magnitude of impact of rain drops on said sensor surface, and thus indicative of rain conditions, comprising:

• a sensor housing;
• a vibrator having said sensor surface and suspended in said sensor housing for vibration in response to the impact of the rain drops onto the sensor surface, said vibrator being formed of a single piece of essentially flat plate with a bend extending around said essentially flat sensor surface, said bend being so formed as to determine a resonant frequency of said vibrator outside of the vibration frequency range within vibrations may be transmitted through the vehicle body;
• and
• means for converting the vibrator vibrations into said sensor signal.

A rain sensor for an automotive wiper control system which is adapted to control wiper operation depending upon rain conditions, said rain sensor having a sensor surface exposed outside of the vehicle and positioned adjacent a windshield of the vehicle, and adapted to produce a sensor signal representative of impact exerted by rain drop onto said sensor surface, comprising:

• a hollow sensor housing;
• a vibrator of generally disc-shaped configuration and having said sensor surface in substantially flat section, the periphery of said vibrator being resiliently suspended within said sensor housing for oscillation depending upon impact exerted by the rain drops, and said vibrator having a bent section extending substantially along said periphery, said bent section being so arranged as to place the resonant frequency of said vibrator in a frequency range outside of a resonant frequency range of the vehicle body;
• and
• means for converting the vibrator vibrations into said sensor signal.