JPS60135673A - Reciprocating driving device - Google Patents

Abstract

PURPOSE:To permit to hold the stroke and period of reciprocating motion of a driving member of shape-memory alloy in constant by a method wherein the amount of conduction of electricity for the driving member of shape-memory alloy is changed in accordance with an ambient temperature to keep the temperature of the driving member constant. CONSTITUTION:A coil spring 20, as the driving member, is conducted and heated alternately by the output signals of a conduction and heating periods setting circuit to drive airflow direction panels 14. The amount of conduction of electricity for the coil spring 20 is reduced by reducing the duty ratio of said output signal when the ambient temperature of the coil spring 20 is high while the same amount is increased by increasing the duty ratio of said output signal when the ambient temperature is low on the contrary. According to this method, the temperature of the driving member may be kept constant in spite of the variation of the ambient temperature and the stroke as well as the period of the reciprocating motion of driving member may be maintained constant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reciprocating drive device, and more particularly to a drive device using shape memory alloy means that changes shape into a predetermined shape due to temperature changes as a reciprocating drive source.

2. Description of the Related Art Various configurations of reciprocating drive devices for reciprocating a predetermined member are known. These include those that use a motor as a drive source and convert its rotational motion into reciprocating motion, and those that use fluid pressure to directly generate reciprocating motion, such as diaphragms and cylinders. However, these have inherent problems such as requiring a speed reducer and space for piping, and are not necessarily suitable for all uses. For example, in an automatic wind direction adjustment device that is installed at the wind outlet of an air conditioner and is designed to periodically change the wind blowing direction, the reciprocating motion is used to swing the blades to control the wind direction. However, if a motor using a speed reducer is used as a drive source for the reciprocating drive system for such an automatic wind direction adjustment device, the operating sound of the motor and speed reducer will generate noise and cause problems during use. However, if the diaphragm is used as a driving source, there will be problems in securing space for the piping.

On the other hand, it is conceivable to use a shape memory alloy means whose shape changes into a predetermined shape due to temperature changes as a drive source of the reciprocating drive device. If shape memory alloy means are used as a drive source, reciprocating motion can be achieved by heating and dissipating heat, so noise will not be a problem as with motors, and electrical wiring for energized heating will not be a problem. However, since the required space is smaller than that for fluid piping such as a diaphragm, securing space is not so much of a problem. However, when such a shape memory alloy means is used as a drive source for a reciprocating drive device, a problem arises in that the stroke of the reciprocating motion changes depending on the surrounding environmental temperature. This is extremely inconvenient in cases where the environmental temperature varies significantly depending on the temperature of the air blown out, such as in equipment.

That is, when a shape memory alloy means is used as a driving source, the force that tends to change the shape of the shape memory alloy means to the memorized shape changes depending on the temperature, so usually,
It is possible to keep the period and stroke of the reciprocating motion constant by keeping the cycle of the energization heating period constant and the amount of current applied within the energization heating period constant, but it is possible to keep the cycle and stroke of the reciprocating motion constant. If the amount of current applied during that period is kept constant, if the surrounding environment temperature is too low, the temperature of the shape memory alloy means may rise to a predetermined temperature even at the end of the current applied heating period. ,
Therefore, the shape change is insufficient, making it impossible to obtain the desired stroke.On the other hand, if the surrounding environment temperature is too high, the temperature will rise more than necessary at the end of the current heating period, causing the reciprocating movement. Not only will the stroke become too large, but there is also a risk that the memory of the shape memory alloy means will fade, ie, so-called memory blur.

The present invention has been made in view of the above circumstances, and its purpose is to provide a reciprocating drive device using a shape memory alloy means as a drive source, and to provide a reciprocating drive device using a shape memory alloy means as a drive source. An object of the present invention is to provide a reciprocating drive device capable of keeping the cycle and stroke of reciprocating motion constant regardless of changes in the environmental temperature around the location.

In order to achieve this object, the present invention uses a shape memory alloy means that changes shape into a predetermined shape due to temperature changes, and uses the shape change effect to cause a predetermined member to reciprocate. (a) energization heating period setting means for setting an energization heating period for the shape memory alloy means at a predetermined cycle;
(b) an environmental temperature detection means that is provided in the vicinity of the arrangement position of the shape memory alloy means and detects the environmental temperature around the shape memory alloy means; Based on the environmental temperature, the amount of current applied to the shape memory alloy means during the current heating period set by the current heating period setting means is determined so that the temperature of the shape memory alloy means is always approximately constant regardless of the environmental temperature. The present invention is configured to include a current supply amount control means for controlling the temperature so that the temperature reaches .

In this way, if the shape memory alloy means is used as the drive source of a reciprocating drive device, the operating noise will not be a problem unlike a motor, and there will be no problem of securing space for piping such as a diaphragm. There are no words that arise.

Further, an environmental temperature detecting means for detecting the ambient temperature around the shape memory alloy means is provided in the vicinity of the disposed position of the shape memory alloy means, and the shape of the shape during the current heating period is determined based on the environmental temperature detected by the environmental temperature detecting means. Since the amount of electricity supplied to the memory alloy means is controlled so that the temperature of the shape memory alloy means is always kept at a substantially constant temperature, the shape memory alloy means can reliably maintain a predetermined shape even if the surrounding environmental temperature changes. A constant stroke can be obtained by changing the shape, and even if the environmental temperature becomes high, the temperature of the shape memory integration means will not rise too much and cause memory blur. Note that the period of the reciprocating motion is kept constant at the period set by the energization heating period setting means.

Hereinafter, in order to clarify the present invention more specifically,
One embodiment thereof will be described in detail based on the drawings.

First, FIG. 1 is an explanatory diagram showing an example of an automatic wind direction adjustment device equipped with a reciprocating drive device, which is an embodiment of the present invention. A housing provided at an air outlet, the opening 1 of which
The wind is blown out from 2,
A plurality of wind direction plates 14 are provided within the opening 12 to control the direction of wind blowing. These wind direction plates 14
are supported by a support shaft 16 pivotally supported by the housing 10 at their center portions so as to be parallel to each other, and their end portions on the inner side of the housing are pivotally supported by a connecting plate 18. Coil springs 20 are arranged between the connecting plate 18 and the picture side wall of the housing 10, and in this embodiment, these coil springs 20 are made of Cu.
The shape memory alloy means is made of a shape memory alloy such as -Zn-AA type or Nt-Ti type.

As shown in the coil spring 20 on the right side of FIG. 1, each of these coil springs 20 has a shape shortened to a predetermined length memorized in advance, and also has a shape that is shortened to a predetermined length. An energization heating circuit 22 is connected, and both coil springs 20 are alternately energized and heated by this energization heating circuit 22 at a predetermined period.

Then, due to a change in the balance of forces of both coil springs 20, which try to change their shape to a memorized shape according to the heating state due to the alternating current heating, the connecting plate 18 is reciprocated from side to side in the figure, and the wind direction plate 14 can be oscillated around a support shaft 16.

The energization heating circuit 22 has a configuration as shown in FIG. 2, for example.

In FIG. 2, reference numeral 24 denotes an energization heating period setting circuit, and as shown in FIG. is directly supplied to one input terminal of the first AND circuit 26, and is inverted by the inverter 28 as an inverted energization heating period signal sc' as shown in FIG. 3(b). It is designed to be supplied to one input terminal of 30.

Further, in FIG. 2, reference numeral 32 denotes an intermittent signal generation circuit, in which a capacitor 36 is connected between the input terminal of a Schmitt circuit 34 having hysteresis characteristics and the ground, and the capacitor 36 is connected between the output terminal of the Schmitt circuit 34 and the capacitor 36.
(input terminal of Schmitt circuit 34), thermistor 38. A charging circuit 42 consisting of a fixed resistor 39 and a diode 40, a fixed resistor 44 and a diode 4
The intermittent signal SI has a duty ratio that changes depending on the resistance value of the thermistor 38 of the charging circuit 42.
and outputs this to the first and second AND circuits 26.
30 remaining input terminals. The thermistor 38 has a so-called NTC characteristic in which the resistance value decreases as the temperature rises, and as shown in FIG. ing. That is, the intermittent signal ST supplied to the AND circuit 26.30 is such that when the temperature of the wind blown out from the opening 12 of the housing 10 is low, the combined resistance value of the charging circuit 42 becomes large.
As shown in FIG. 3(c), the duty ratio increases, and when the wind temperature is high, the combined resistance value of the charging circuit 42 decreases, and the duty ratio increases as shown in FIG. 3(C)'. It is designed to become smaller.

Both AND circuits 26.30 are (d+, (d)) in FIG.
' and (el, as shown in (el'), when the energization heating period signal SC is at the ■] level,
and when the inverted energization heating period signal SC" is at H level,
The intermittent signal sr is passed through and supplied as first and second energization heating signals SHI and SH2 to the first and second energization amplifier circuits 50 and 52, respectively. Each of the energizing amplifier circuits 50 and 52 alternately energizes and heats the pair of coil springs 20 in accordance with the supplied energizing heating signals SHI and SH2.

That is, each coil spring 20 is alternately energized and heated according to the cycle of the energization heating cycle signal SC, which is the output of the energization heating cycle setting circuit 24. Therefore, the wind direction plate 14
In other words, the connecting plate is made to reciprocate in a period determined by the period per day, but in this embodiment, the amount of current applied to each coil spring 20 during the energization heating period is as follows:
When the environmental temperature around the coil spring 20 is high, it is reduced by decreasing the duty ratio of the intermittent signal S as described above, and when the surrounding environmental temperature is low, the duty ratio of the intermittent signal SI is increased. As shown in (f), (fl' and (6), fgl' in FIG. The temperature of the spring 20 is always maintained at a substantially constant temperature (the temperature indicated by T in FIG. 3), and as a result, the swing angle of the wind direction plate 14 is adjusted to the reciprocating motion of the connecting plate 18. The stroke is maintained almost constant.

Note that, as is clear from the above description, in this embodiment, the energization heating period setting circuit 24. The AND circuits 26 and 30 and the inverter 28 constitute energization heating period setting means, the thermistor 38 constitutes temperature detection means, and the intermittent signal generation circuit 32 constitutes energization amount control means.

As described above, according to this embodiment, since the coil spring 20 made of shape memory alloy is used as the drive source for reciprocating the connecting plate 1B, the operating noise is extremely quiet, and the coil spring 20 is used as the drive source for reciprocating the connecting plate 1B. This has the advantage that it requires less space than when using a motor, diaphragm, etc., and the automatic wind direction adjustment device can be configured compactly.

In addition, since the temperature at the end of the energization heating period is always kept almost constant, not only is the stroke of the reciprocating motion kept constant, but also memory loss may occur in the coil spring 20 due to an unnecessarily increased temperature. The fear of being attacked is gone.

Moreover, according to the present embodiment, since the coil spring 20 is intermittently heated by electricity, the temperature distribution of the coil spring 20 is averaged and temperature deviation is eliminated. This has the advantage that memory blur due to a partial temperature rise can be avoided.

Although one embodiment of the present invention has been described above, this is a literal illustration, and the present invention should not be interpreted as being limited to this embodiment.

For example, in the embodiment described above, the pair of coil springs 20 as shape memory alloy means directly drive the connecting plate 18 to give it reciprocating motion, but such a shape memory alloy means is not necessarily required. It is not necessary to directly drive the reciprocating motion by interposing a predetermined intermediate member, and the a-alloy means may have a shape other than a coil spring shape. It is also possible to adopt Furthermore, the shape memory alloy means does not need to utilize the shape change of two shape memory alloys, but may be constructed by combining a normal spring member and one shape memory alloy. Furthermore, the memorized shape during electrical heating does not necessarily have to be a shortened shape, and can be changed as appropriate depending on the situation.

Further, in the above embodiment, the thermistor 38 having NTC characteristics is used as the temperature detection means, and this thermistor 38 is inserted into the charging circuit 42 of the intermittent signal generating circuit 32, so that the resistance value of the thermistor 38 changes due to temperature. Based on this, the H level time of the intermittent signal 31 from the intermittent signal generation circuit 32 is controlled, thereby controlling the energization heating signal SHI,
The duty ratio of SH2 was controlled to control the amount of current flowing through the coil spring 20 as a shape memory alloy means, but the thermistor 38 was equipped with a PTC characteristic in which the resistance value increases as the temperature rises. This is provided on the discharge amount path 48 side of the intermittent signal generation circuit 32, and the duty ratio of the energization heating signals SH1 and SH2 is controlled by controlling the time of the 14 levels of the intermittent signal Sl.
In this manner, the amount of current flowing through the coil spring 20 may be controlled, or the amount of current flowing through the coil spring 20 may be controlled by simultaneously controlling the times of the H level and L level. Note that the thermistor 38 does not necessarily need to be connected in series with a fixed resistor as in the above embodiment, and may be used as part of a composite resistance circuit in combination with a plurality of fixed resistors. Further, it is also possible to use something other than a thermistor as the temperature detection means, and furthermore, various oscillation circuits can be used as the intermittent signal generating circuit 32.

Furthermore, the amount of energization within the energization heating period does not necessarily have to be controlled by controlling the duty ratio of the intermittent signal SI, and may be performed by controlling the amplification factor of each energization amplifier circuit 50, 52. In this way, a continuous signal is generated instead of the intermittent signal Sl, and each energizing amplifier circuit 50 . The amount of energization may be controlled by controlling the amplification factor in '52.

In addition, in the embodiment described above, the present invention is applied to a reciprocating drive device of an automatic wind direction adjustment device, but it goes without saying that the present invention can also be applied to a reciprocating drive device of other devices.

Although not listed here, it goes without saying that the present invention can be practiced with various modifications and improvements within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of an automatic wind direction adjustment device equipped with a reciprocating drive device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an example of the energization heating circuit of FIG. 1. 3 is a time chart showing a comparison of the signal waveforms of various parts of the energization heating circuit of FIG. 2 and the state of temperature change of the coil spring in two states in which the environmental temperature of the coil spring of FIG. 1 is different. 18: Connecting plate 20: Coil spring (shape memory alloy means) 22: Current supply heating circuit 32: Intermittent signal generation circuit (current supply amount control means) 38: Thermistor (temperature detection means) Applicant: Kojima Press Kogyo Co., Ltd. Figure 1 Figure 3

Claims (1)

[Scope of Claims] A reciprocating drive device that uses shape memory alloy means that changes shape into a predetermined shape due to temperature changes, and uses the shape change effect to cause a predetermined member to reciprocate, energization heating period setting means for setting the energization heating period for the shape memory alloy means at a predetermined cycle; an environmental temperature detection means to detect; and an amount of current applied to the shape memory alloy means within the energization heating period set by the energization heating period setting means based on the environmental temperature detected by the environmental temperature detection means;
A reciprocating drive device comprising: an energization amount control means for controlling the temperature of the shape memory alloy means so that the temperature is always substantially constant regardless of the environmental temperature.