JPH0470540B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an air passage switching device that switches between a plurality of air passages using a damper.

Conventional structure and its problems Conventionally, this type of air path switching device was constructed as shown in Figs.
As shown in the figure, a blowing means 1, a heating means 2, blowing paths 3a and 3b, a damper 4 for switching between the plurality of blowing paths 3a and 3b, a solenoid 5 for driving the damper 4, a return spring 6, and a control means. It consists of 7. In Fig. 1, air can be blown to the air passage 3a,
On the other hand, FIG. 2 shows a state in which air can be blown into the air passage 3b.

The above configuration has the disadvantage that the air path switching device becomes large because a solenoid is used to drive the damper.

Further, FIGS. 3 and 4 are configuration diagrams of the main body for driving the damper 4 using the shape memory alloy 8. FIG. 5 is a control circuit diagram, including a terminal 9 for passing current through the shape memory alloy 8, and a relay contact (switch) 10 forming a parallel circuit with the shape memory alloy.
(normally closed), alternating current 11, bidirectional trigger element group 12, transistor group 13, air path switching command means 1
It consists of 4. FIG. 6 is a control sequence diagram of a conventional example.

In the above configuration, in order to switch the air path from the state shown in FIG. 3 to the state shown in FIG. The driving point temperature of the shape memory alloy 8 must be created by self-heating (because the resistance of the shape memory alloy is several ohms). This is because hot air does not reach the shape memory alloy 8 in the hot air path 3a, making it impossible to create a driving point temperature. Therefore, without creating a special power supply circuit to flow 4A, the shape memory alloy 8 and the relay contact (switch) 10 can be configured in a parallel circuit, and the parallel circuit and
By configuring the heating means 2 as a series circuit and opening the relay contact (switch) 10 for a certain period of time, if the wattage of the heating means is, for example, 400 W, a current of about 4 A will flow through the shape memory alloy 8. The driving point temperature is reached and a contraction force is generated. (Figure 6 15)
Therefore, the damper 4 opposes the restoring force of the return spring 6 and forms the hot air path 3b. After the hot air path 3b is formed, the relay contact (switch) 10
Even if the shape memory alloy 8 is closed and no current is passed through the shape memory alloy 8,
This time, the shrinkage force of the shape memory alloy 8 is maintained by the temperature of the hot air produced by the blowing means 1 and the heating means 2, and the hot air path 3b continues to be formed.

Next, when switching from the hot air path 3b in FIG. 4 to the hot air path 3a in FIG.
Stop the heating means 2. (FIG. 6, 16) Then, the shape memory alloy 8 is no longer able to hold itself, and the restoring force of the return spring 6 forms the hot air path 3a. Thereafter, the control means 7 energizes the blower means 1 and the heating means 2 again, and warm air is blown into the hot air path 3a. However, in the above configuration, while the blower fan 1 and the heating means 2 are temporarily stopped, the damper 4 is activated by the return spring 6, and the control means 7 is activated by the blower before the hot air path 3b is completely closed. 1. When the heating means 2 is energized, hot air hits the shape memory alloy 8, and due to the shrinkage force, a problem arises in that the hot air path 3a that should originally be formed becomes a hot air path 3b. . In addition, the time management for temporarily stopping the blowing means 1 and the heating means 2 and creating the hot air passage 3a is affected by the ambient temperature around the shape memory alloy 8, and the time required to switch the air passage is long. This is a difficult design, and the fact that the blower means 1 and the heating means 2 are stopped sufficiently to prevent malfunctions gives rise to the problem of giving the user a feeling of anxiety that something might be wrong.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a device which solves the above-mentioned conventional objects and which allows smooth air passage switching without malfunctions with an extremely simple control sequence.

Structure of the Invention In order to achieve this object, the present invention includes a blowing means, a heating means, two hot air passages provided downstream of the heating means, and a damper for switching between the two hot air passages. , a shape memory alloy provided in one of the two hot air paths and provided at one end of the damper, and a return acting in the opposite direction to the force generated on the shape memory alloy to open/close and balance the damper. The shape memory alloy and the switch are composed of a spring, a switch that applies a current to create a driving point temperature of the shape memory alloy, a control means that energizes the switch, and an air path switching command means, and the shape memory alloy and the switch: The parallel circuit and the heating means are constructed as a series circuit, and the control means opens the contacts of the switch for a predetermined period of time in response to a signal from one of the air path switching command means, thereby causing the shape memory alloy to The heating means is configured to be energized, and the heating means is stopped for a predetermined period of time in response to a signal from the other side of the air path switching command means, and only the blowing means is energized.

With this configuration, the hot air path can be switched simply by temporarily opening and closing the contacts of the switch and temporarily stopping the heating means.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the main body configuration diagrams shown in FIGS. 3 and 4, the control circuit diagram shown in FIG. 5, and the control sequence diagram shown in FIG. 7.

The difference from the conventional example is that the signal from the air path switching command means 14 shown in FIG.
When switching to the hot air path 3a shown in the figure, the cold air is blown onto the shape memory alloy while the blowing means 1 remains energized and the heating means 2 is not energized for a certain period of time. (FIG. 7) Then, the shape memory alloy is unable to retain its shape and is forcibly expanded by the restoring force of the return spring 6, switching to the hot air path 3a of FIG. 3 much faster than in the conventional example. Thereafter, when the heating means 2 is energized again, the hot air flows through the hot air path 3a. Note that the switching of the air path from the hot air path 3a to the hot air path 3b in FIG. 3 is the same as in the conventional example, and will therefore be omitted.

In addition, in Figure 5, a relay contact was used as a switch to send current to the shape memory alloy, but
It may be a semiconductor switch, and is not limited to the above embodiment.

Effects of the Invention According to the present invention, the blowing means, the heating means,
a damper that switches hot air paths; a shape memory alloy that drives the damper; and a force that acts in the opposite direction to the shape memory alloy to open and close the damper.
It consists of a return spring for balance, a switch that sends current to the shape memory alloy, a control means that energizes the switch, and an air path switching command means.The shape memory alloy and the switch are configured in a parallel circuit, and the parallel circuit and the heating Since the means is composed of a series circuit, the heating means can be switched for a certain period of time by a signal from the air passage switching command means. Since the damper is driven by blowing cold air onto the shape memory alloy while the air blowing means is energized without being energized, the hot air path can be switched with a simple control sequence of the control means, and two hot air paths can be switched. Mutual switching of the air passages is performed instantly, and the opening/closing mechanism of the air passage switching device and the damper can be made smoothly and compactly. Furthermore, since the two hot air paths can be switched quickly, there is no malfunction due to a mistake in switching between the hot air paths, so the user does not feel uneasy.

In addition, since the shape memory alloy is located in the hot air path after the damper is switched, the structure only requires electricity to be applied to the shape memory alloy for a limited period of time, which prevents deterioration of the shape memory alloy and increases reliability. Improves sex. Furthermore, when switching the air path, if the predetermined time for blowing cold air and the amount of electricity applied to the heating means are made minute, for example, the restoring force of the return spring and the force generated in the shape memory alloy will be balanced, and the It has the effect of being able to simultaneously blow cold air onto the road.

[Brief explanation of the drawing]

FIGS. 1 and 2 are main part configuration diagrams of a conventional example of an air path switching device, and FIGS. 3 and 4 are main part configuration diagrams of another conventional example and an air path switching device of an embodiment of the present invention. , 5th
FIG. 6 is a circuit diagram of the same control circuit, FIG. 6 is a conventional control sequence diagram, and FIG. 7 is a control sequence diagram of an air path switching device according to an embodiment of the present invention. 1... Air blowing means, 2... Heating means, 3a, 3b
... Warm air path, 4 ... Damper, 7 ... Control means,
8... Shape memory alloy, 10... Switch (relay), 14... Air path switching command means, 15... Flow part that opens the switch only for a certain time, 17...
A flow section that does not energize the heating means for a certain period of time.

Claims (1)

[Claims] 1. A blowing means, a heating means, a pair of hot air passages provided downstream of the heating means, a damper for switching between the pair of hot air passages, and a damper provided on one of the pair of hot air passages. a shape memory alloy provided at one end of the damper; a return spring that acts in the opposite direction to the force generated on the damper to open, close, and balance the damper; and the shape memory alloy for driving the shape memory alloy. The shape memory alloy and the switch are configured in a parallel circuit, and the parallel circuit and the heating device are connected in series. The control means is configured to open the contacts of the switch for a predetermined period of time in response to one signal from the air path switching command means and energize the shape memory alloy; An air path switching device configured to stop a heating means for a certain amount of time and energize only a blowing means.