"Blower Fan" for this development, in order to shorten the length of the front and rear HVAC damper does not use switch-mode, instead of using a sliding door. Moreover, in order to maximize the size of the effect, and the driving part throttle damper the required rack (gear) is integrally molded part. The choice of material will take a lot of work. Rack portion need to have the drive without distortion rigidity (stiffness), while the throttle section will need the wind pressure deformation can be tightly sealed soft. That is hard and soft at the same time meet two contradictory characteristics.