Abstract: An HVAC blower motor (10) includes a stator (12) and a rotor (14). The stator (12) include electro-magnets (12a) energized at pre-determined energizing frequency. The rotor (14) angularly moves relative to the stator (12) due to pulsating magnetic field between the stator (12) and the rotor (14). The rotor (14) includes an output shaft (24), a magnet holder (14a) and a plurality of permanent magnets (20). The permanent magnets (20) are configured to interact with the cyclically energized electro-magnets (12a) to cause pulsating magnetic field between the stator (12) and the rotor (14) to cause angular movement of the rotor (14) relative to the stator (12). The magnet holder (14a) includes a strip (15) of vibration damping material secured thereto along an outer periphery thereof to change the natural frequency characteristic of the wall portion 14c is subjected to.

Abstract: A HVAC system includes a housing including at least one wall, an air flow path defined at least partially by the at least one wall, and a door disposed in the air flow path, where the door is configured to i) block a flow of air through the air flow path when the door is in at least one closed position, and ii) allow the flow of air through the air flow path when the door is in a position other than the at least one closed position. A gap is formed between the door and the at least one wall when the door is in the position other than the at least one closed position. The HVAC system further includes a noise-reducing feature defined on at least a portion of the at least one wall. The noise-reducing feature configured to break up, into several smaller structures, an air flow structure formed when air flowing through the gap contacts an end of the door, thereby reducing air vibration in the gap and reducing noise of the HVAC system during operation thereof.

Abstract: A HVAC system includes a housing including at least one wall, an air flow path defined at least partially by the at least one wall, and a door disposed in the air flow path, where the door is configured to i) block a flow of air through the air flow path when the door is in at least one closed position, and ii) allow the flow of air through the air flow path when the door is in a position other than the at least one closed position. A gap is formed between the door and the at least one wall when the door is in the position other than the at least one closed position. The HVAC system further includes a noise-reducing feature defined on at least a portion of the at least one wall. The noise-reducing feature configured to break up, into several smaller structures, an air flow structure formed when air flowing through the gap contacts an end of the door, thereby reducing air vibration in the gap and reducing noise of the HVAC system during operation thereof.