1. Field of the Invention
This invention relates to a damper door for a heating and cooling system for a vehicle and, more particularly, to a damper door with an integral seal. The invention also relates to a method for manufacturing the damper door with an integral seal.
2. Related Art
Vehicle heating and cooling systems have an air conduit with multiple outlets for discharging flow to the air into a cabin of the vehicle, dampers for selectively opening or closing the outlets, and a drive device for each damper. These dampers may include a carrier plate having a foam seal formed on one or both faces of the carrier plate, preferably near the periphery of the faces, or about the peripheral edge of the carrier plate. The seal, when the damper is rotated to a closed position, blocks air from passing about the periphery of the damper. The sealing material is adhered to the carrier plate by a conventional adhesive applied between the carrier plate and the sealing material. This method of assembly is time and labor intensive. Even if the process is automated, application of the adhesive to the carrier plate and aligning the sealing material with the carrier plate are additional steps in the assembly process.
A conventional heating and cooling system includes an air conduit connecting a blower, an evaporator, and a heater core. The blower generates an air flow directed to the cabin of the vehicle. The evaporator is in a refrigeration cycle whereby a heat exchange of the air flow with a cooling medium inside the evaporator cools the air flow. The heater core has an inner passageway connected to a cooling water passageway of an internal combustion engine so that hot engine cooling water from the passageway is introduced into the inner passageway of the heater core, whereby a heat exchange of the air flow of the engine cooling water warms the air flow to obtain a desired temperature of the air. A hot air passageway includes a damper positioned upstream of the heater core for controlling the ratio of air passing through the heater core to the amount of air bypassing the heater core, whereby a desired temperature of the air directed to the cabin is obtained. Similarly, a cool air passageway is opened or closed by a damper for introducing cooled air from the evaporator to various outlets or vents in the passenger cabin according to the operator""s temperature selection The degree of opening of the dampers in the air passageways to the evaporator or heater core controls the temperature in the passenger cabin.
According to the invention, a damper for selectively opening or closing an air passageway in a vehicle heating and cooling system includes a rigid carrier plate having opposed faces defined by a periphery with a shape generally corresponding to but smaller than the shape of a cross-section of the air passageway and formed of a material having a melting point above an activation temperature range. A heat-expandable sealing material, which is adapted to expand at a temperature in the activation temperature range, is mounted to at least one of the opposed faces of the rigid carrier plate. The sealing material, when activated, expands radially from the rigid carrier plate to form an integral seal with the carrier plate.
Further according to the invention, a damper for selectively opening or closing an air passageway in a vehicle heating and cooling system includes a rigid carrier plate having opposed faces defined by a periphery with a shape generally corresponding to but smaller than the shape of a cross-section of the air passageway and formed of a material having a melting point above an activation temperature range. A heat-expanded foam sealing material, which has been expanded at a temperature in the activation temperature range, is mounted to at least one of the opposed faces of the rigid carrier plate. The sealing material forms an integral seal with the carrier plate.
In one embodiment of the invention, the sealing material is integrally molded to at least one of the opposed faces of the rigid carrier plate. In another embodiment, the opposed faces include a peripheral edge and the seal is formed about the peripheral edge. In a further embodiment of the invention, the heat-expandable sealing material is integrally molded to the outer periphery of the rigid carrier plate.
A process for forming a damper with an integral seal according to the invention includes forming a rigid carrier plate with a material that has a melting point above an activation temperature range and having an outer periphery with a shape generally corresponding to but smaller than the shape of a cross-section of the air passageway; integrally molding a heat-expandable sealing material to the outer periphery of the carrier plate, the heat-expandable sealing material being adapted to expand in the activation temperature range; heating the sealing material into the activation temperature range; and expanding the sealing material radially from the carrier plate to fill a peripheral space between the sealing material and walls of a mold restricting expansion of the sealing material.
In one embodiment of the invention, the forming step includes injection molding. In another embodiment, the integrally molding step comprises injection molding. A further embodiment includes sequentially molding the carrier plate and the sealing material in a two-step molding operation.