초록 ▼

In an air passage switching device, suitable for use for example in a vehicle air conditioning apparatus, for switching a flow of air among a plurality of air passages by moving a film door in one direction by a stepping motor and in another direction by the spring force of coil spring, when the fil

In an air passage switching device, suitable for use for example in a vehicle air conditioning apparatus, for switching a flow of air among a plurality of air passages by moving a film door in one direction by a stepping motor and in another direction by the spring force of coil spring, when the film door is moved in the direction in which it winds up the coil spring the pulse rate of the stepping motor is reduced to thereby increase the motor torque and prevent the occurrence of a shortage of motor torque. When the film door is moved in the other direction the pulse rate of the stepping motor is increased to reduce the motor torque.

대표청구항 ▼

[ What is claimed is:] [1.]1. An air passage switching device for switching a plurality of air passages, comprising:a film having a first end and a second end for switching the air passages;a first rotation shaft to which said first end of said film is connected;a second rotation shaft to which said

[ What is claimed is:] [1.]1. An air passage switching device for switching a plurality of air passages, comprising:a film having a first end and a second end for switching the air passages;a first rotation shaft to which said first end of said film is connected;a second rotation shaft to which said second end of said film is connected, said second rotation shaft having an elastic member; anda stepping motor connected to said first rotation shaft for rotating said first rotation shaft, wherein;said elastic member is deformed to increase its elastic force as said second rotation shaft rotates when said first rotation shaft is rotated in a first rotational direction by said stepping motor such that said first end of said film is wound up by said first rotation shaft;said second rotation shaft is rotated by said elastic force of said elastic member such that said second end of said film is wound up by said second rotation shaft when said first rotation shaft is rotated in a second rotational direction opposite to said first rotational direction by said stepping motor and when said first end of said film is unwound from said first rotation shaft; anda relation between a first pulse rate applied to said stepping motor when said first end of said film is wound up by said first rotation shaft and a second pulse rate applied to said stepping motor when said second end of said film is wound up by said second rotation shaft is established in such a manner that said first pulse rate is less than said second pulse rate.