Ventilation – Vehicle – Condensation preventer
Reexamination Certificate
1999-08-19
2001-10-02
Lu, Jiping (Department: 3749)
Ventilation
Vehicle
Condensation preventer
C454S156000, C454S159000, C454S160000, C251S901000
Reexamination Certificate
active
06296562
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims priority from Japanese Patent Application Nos. Hei 10-254021 filed Sep. 8, 1998, and Hei 10-312327 filed Nov. 2, 1998, and Hei 10-348780 filed Dec. 8, 1998, and Hei 10-350310 filed Dec. 9, 1998, and Hei 11-66946 filed Mar. 12, 1999, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an air passage switching device for switching air passages by moving in the air passages a film member (film door) in which are formed openings for air to pass through, and an air conditioning apparatus in which this air passage switching device is used.
2. Related Art
Air passage switching devices for switching air passages by moving a film door of this kind in related art include for example that disclosed in Japanese Patent Application Laid-Open No. H8-2238. In this related art, the ends of a flexible film door such as a resin film are joined to a driving shaft (first rotating shaft) and a driven shaft (second rotating shaft) rotatably mounted in an air-conditioner case; the ends of the two shafts are coaxially connected to pulleys, and the ends of a wire are wound around these pulleys. A motor is connected to the driving shaft and rotates the driving shaft.
When the driving shaft rotates in the direction in which it takes up the film door, the driving shaft directly takes up the film door and the film door moves. Conversely, when the driving shaft rotates in the direction in which it lets out the film door, this rotation of the driving shaft is transmitted to the driven shaft via the pulleys and the wire, and the driven shaft rotates in the direction in which it takes up the film door and the film door is thus moved and taken up by the driven shaft.
By the film door being moved in forward and reverse directions inside the air conditioner case in this way, air passages such as ventilation air passages leading to a vehicle passenger compartment can be switched freely.
However, in this related art, interference between moving members, such as the pulleys and the wire, and parts such as a ventilation duct around the air conditioner case has been a problem, and the freedom of design of these parts has diminished, resulting in increased manufacturing cost.
Furthermore, because a mechanism connecting two pulleys with a wire is provided as described above to make the driving shaft and the driven shaft cooperate, there has been the problem that the number of parts in the apparatus as a whole is increased, its assembly is complicated, and its cost is increased.
In German Patent No. 3,514,358, an air passage switching device using a film door in which it is possible to dispense with the above-mentioned connecting mechanism (pulleys and wire) is disclosed.
FIG. 29
shows schematically the basic construction of this related art dispensing with the connecting mechanism. As shown in
FIG. 29
, it has a driving motor
100
, a driving shaft
101
, a film door
102
and a driven shaft
103
, and a driving coil spring
104
is connected to the driven shaft
103
.
According to this related art, when the driving shaft
101
is rotated by the driving motor
100
in the direction {circle around (1)} in which it takes up the film door
102
, the driven shaft
103
is rotated by the film door
102
and winds up the coil spring
104
. And when the driving shaft
101
is rotated by the driving motor
100
in the opposite direction {circle around (2)} in which it lets out the film door
102
, because the coil spring
104
unwinds under its own spring force, the driven shaft
103
is rotated back in that direction by the spring force of the coil spring
104
and the film door
102
is taken up by the driven shaft
103
.
According to this related art, because when the driving shaft
101
is driven by the driving motor
100
to rotate in the direction {circle around (1)} in which it takes up the film door
102
the coil spring
104
is wound up, the spring force due to winding of the coil spring
104
increases in proportion to the distance moved (stroke) of the film door
102
. In other words, the operating force on the film door
102
increases in proportion to the distance moved by the film door
102
.
This will now be explained with reference to
FIG. 5
, in which {circle around (1)} and {circle around (2)} respectively correspond to the direction {circle around (1)} in which the film door
102
is taken up by the driving shaft
101
and the direction {circle around (2)} in which it is returned to the driven shaft
103
in FIG.
29
. When the film door
102
is taken up by the driving shaft
101
(movement direction {circle around (1)},) the wound up amount of the coil spring
104
increases as the movement distance of the film door
102
increases. Accordingly, the torque T
1
necessary for the winding up of the coil spring
104
increases.
Here, the torque T
0
required to move the film door
102
is always fixed, irrespective of the distance moved by the film door
102
, and therefore, when the film door
102
is taken up by the driving shaft
101
, the film door take-up torque required of the driving motor
100
increases as the distance moved by the film door
102
increases, as shown with the solid line {circle around (1)} in FIG.
5
.
When on the other hand the film door
102
is returned from the driving shaft
101
to the driven shaft
103
(movement direction {circle around (2)}), the coil spring
104
unwinds under its own spring force and the driven shaft
103
is rotated in the opposite direction by the spring force of the coil spring
104
and the driven shaft
103
takes up the film door
102
, and therefore the film door take-up torque required of the driving motor
100
becomes zero, as shown with the solid line {circle around (2)} in FIG.
5
.
However, in this related art, there is no mention of countermeasure for the operating force on the film door
102
, which increases with the stroke of the film door
102
. Consequently, there may be a risk of a torque shortage of the driving motor
100
during the process of moving the film door
102
in the direction {circle around (1)} in which the coil spring
104
is wound up and of consequent defective operation of the film door
102
.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to, in an air passage switching device which switches air passages by moving a film door and moves the film door in one direction by means of a driving motor and moves the film door in another direction by means of an elastic force, prevent a shortage of driving motor torque arising when the film door is moved in the direction in which the elastic force increases as the distance moved by the film door increases.
It is another object of the present invention to, in an air conditioning apparatus for use in a vehicle, make it possible for switching to a defroster mode to be carried out rapidly.
The present invention is applicable to a device which uses as the motor for driving the film door a stepping motor whose motor rotation (rotation angle) is regulated by pulse number of steps (input pulse count); with this stepping motor, the torque changes as shown in
FIG. 6
with variation in the pulse rate PPS, which is the number of pulses per unit time (normally one second). That is, the motor torque decreases as the pulse rate PPS increases.
Accordingly, the present invention focuses on the pulse rate PPS in the stepping motor, and achieves the above-mentioned objects by associating this pulse rate PPS with the direction of movement of the film door in control.
According to an aspect of the present invention, a first pulse rate which is applied to a stepping motor when one end of a film door is taken up by a first rotating shaft and a second pulse rate which is applied to the stepping motor when the other end of the film door is taken up by a second shaft are set in such a manner that the first pulse rate is less than the second pulse rate.
Accordingly, when one end of the film door is taken
Ohfuji Noboru
Uemura Yukio
Denso Corporation
Harness Dickey & Pierce PLC
Lu Jiping
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