JPS59168282A - Heat responsive device utilizing shape memory spring - Google Patents

Abstract

PURPOSE:To permit to be used for an use which is narrow in an operating temperature range by providing a stopper stopping the shape memory spring at a predetermined operating stroke to reduce the temperature hysteresis of the spring. CONSTITUTION:When temperature is low, a load for a weight 3 tries to compress the spring 1, whose spring constant is weakened, to the lower side of the stopper 5; however, the first stopper 5 receives it. Accordingly, the load of the weight 3 is supported by the resilient force of the spring 1 and the first stopper 5. On the other hand, when the temperature is high, the spring 1 tries to expand more than the operating stroke L thereof; however, the second stopper 6 precludes the restoration exceeding the operating stroke L. Accordingly, the temperature hysteresis may be restricted to a small amount.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal bidynamic device using a shape memory spring made of a shape memory alloy.

If this skeleton's device is dissected, it will be used for things like heat-responsive valves. In other words, this conventional insert device operates a driven object, such as a valve body, with a predetermined operating stroke by utilizing the change in the output load of the shape memory spring between low and high temperatures. , As schematically shown in FIG. 1, ζ2, a coiled shape memory spring a, and this shape memory spring a?
A weight that applies a load in the direction of deflection (load applying body)
When the temperature is low, the output load of the shape memory spring a is small, so the amount of deflection of the spring increases and the way b) falls, while at the crystal temperature, the output load of the shape memory spring a is large. Therefore, way) b rises.

That is, at each temperature, the output load and the spring force of spring a are balanced.

By the way, it has been known for a long time that shape memory alloys have temperature hysteresis (temperature difference in phase transformation). This temperature hysteresis is 10°C to 30°C for the shape memory alloy itself.
'C, which is a relatively small value, but when used as a spring, the temperature hysteresis becomes even larger due to the effect of strain.

In other words, when measuring with 4F hysteresis by changing the weight of load (way) b) in the device shown in Fig. 1, the result shown in Fig. 2 (
5), (to), and (C). Figure 2 (5) shows the case where the load is small, and the temperature hysteresis Δ
T1 is also relatively small, but as the load increases as shown in Figure 2 (F3) and (C1), the temperature hysteresis ΔT gradually increases.
It can be seen that teΔT3 becomes large.

For further understanding, the conventional product will be explained below with specific figures. For example, when the required operating stroke L is 9 wI and the load applied to the spring (weight of weight b) is 75 gf, the shape memory spring a is - As an example, the wire diameter is 0.611 IJI%, the coil average diameter is 8 ld% Effective number of turns: 10, free height: 24U, contact height: 7.3tam'
It is a spring made of l' i-N i alloy, and the phase transformation temperature is
A s = 25°C, A f = 36'C, M s
= 32°C, Mf = 26°C. As shown in FIG. 3, the above-mentioned operating stroke L is the difference L (91! Jl).

As above (two strokes are 9u, the load is 75gf)
The load-deflection diagram in this case is as shown in the $4 diagram.

That is, it means that the difference between the amount of deflection at low temperature and the amount of deflection at high temperature is 9v1.

By the way, the temperature hysteresis when using the 'l'1-Ni shape memory layer a having the above phase transformation temperature is as shown in FIG. In Fig. 2, T indicates the operation start temperature when the temperature is increased, T is the operation end temperature when the temperature is increased, sTs is the operation start temperature when the temperature is decreased, and T4 is the operation end temperature when the temperature is decreased. Also, what is the adhesion height Hs? , 81.

As can be seen from Fig. 5, the conventional shape memory spring a
Then, the difference between T and T4, that is, the temperature (9) hysteresis ΔT
is 32℃, which is more than three times the temperature hysteresis (A/-M, f=10℃) of the shape memory alloy itself.
It will be very large. Is the reason as mentioned above?
- When a shape memory alloy is used as a spring, there is a region where the height of the spring hardly changes even if the temperature changes, between the start temperature and the end temperature due to the addition of strain. be.

As is clear from the above explanation (-1) in the conventional thermal response device, the temperature hysteresis ΔT is very large.Therefore, it was sometimes impossible to use it in a narrow operating range. Because the output load of spring a and the external force (for example, the weight of way b) are balanced.

The operating position is likely to change due to minute fluctuations in external force.

Therefore, it is unsuitable for environments where there are many external force fluctuations, such as outdoors, equipment systems where there are many mechanical vibrations, or valves where there are many fluid pressure fluctuations, which limits its use.

The present invention has been made based on the above circumstances.

The purpose of this is to reduce temperature hysteresis so that it can be used in applications with a narrow operating temperature range, and to use a shape memory spring that does not change its operating position due to external force fluctuations and has high operating stability. An object of the present invention is to provide a thermal response device.

That is, the gist of the present invention is to provide a shape memory spring made of a shape memory alloy, a load applying body such as a weight or a bias spring that applies a load in a direction that causes the shape memory spring to deflect, and a shape memory spring made of a shape memory alloy at low temperatures. It is characterized by comprising at least one of a first stopper that prevents the spring from deflecting beyond a predetermined operating stroke, and a second stopper that prevents the shape memory spring from restoring beyond a predetermined operating stroke at high temperatures. This is a thermal response device using a shape memory spring.

An embodiment of the present invention will be described below with reference to FIGS. 6 to 8.

Figure 6 (F3) shows the state of the thermal response device at low temperature and at high temperature, respectively. 1 in M diagram
In the figure, reference numeral 1 indicates a coiled shape memory spring made of a shape memory alloy.
) [J, average coil diameter 3, lfl, effective number of turns 10. Free height 30u(7)'I'1-Ni spring, or as another example, wire diameter 0.51, coil average diameter 6,41171.
T i -N with effective number of turns 9.75% free height 22.5 mm
Use springs manufactured by i.

However, the specific values of each dimension, such as the number of turns per turn, vary depending on the required specifications, and are not limited to the examples.

Further, the phase transformation temperature of the shape memory spring I is - for example, A
s = 25°C, A, f = 36°C, M s = 32°C
, Mf=26°C, and the temperature hysteresis of this alloy itself is kf−Mf=lo°C.

The shape memory spring 1 is designed to have a shape memory effect so that it reaches its maximum elongation (free height) in the temperature range exceeding a predetermined temperature.

Further, in FIGS. 6(5) and 6(B), numeral 2 in the drawings indicates a rod-shaped IIA moving body. This driven body 2 has a shape memory spring 1 inserted through it, and a weight 3 as an example of a load applying body is absorbed on the upper end thereof, and a second stopper 6, which will be described later, is attached on the lower end thereof. A receiver 54 that approaches and separates is formed.

A first stopper 5 is provided between the weights 3 and the receiving portion 4, and a second stopper 6 is provided below the first stopper 5, and the shape memory spring is provided between the second stopper 6 and the weight 3. 1 is provided in a compressed state.

As shown in the 6th section, the stopper 5 of @l is placed on the lower surface of the weight 3 at low temperatures, that is, in a state where the output load of the shape memory spring I is small and the deflection ()E contraction amount of the spring 1 is large. This is to prevent the spring I from deflecting beyond a predetermined operating stroke L (for example, 911113).

On the other hand, as shown in FIG. 6 (I3), the second stopper 6 is activated when the receiving portion 4 By this contact, the spring I is prevented from restoring beyond a predetermined operating stroke L (for example, 91).

In other words, at the low temperature shown in FIG. 6 (5).

The load of the weight 3 tries to compress the spring 1 whose spring constant is weaker than the first stopper 5, but the first stopper
The stopper 5 stops receiving this. Therefore, the load on weight 3 is.

It is supported by the repulsive force of the spring I and the first stopper 5. On the other hand, when the spring is at high temperature (see FIG. 6), the spring 1 tries to extend beyond the operating stroke L (9 hours), but the second stopper 6 prevents it from restoring any further.

To explain the above with reference to Fig. 7, the load (weight including weight 3, driven body 2, receiving part 4, etc.) is 75F.
Since it is constant at lf, the spring characteristic at low temperature is the deflection (
Since the compression is restricted by the first stopper 5, a load difference ΔP acts on the first stopper 5. Conversely, with the spring characteristics at high temperatures, the restoring force is regulated by the second stopper 6, so that a load difference ΔP acts on the receiving portion 4.

Therefore, in the states shown in Figure 6 (8) and (B), even if the load fluctuates slightly, it is possible to absorb this load fluctuation within the range of ΔP or ΔP2 above, making it extremely stable against external force fluctuations. It becomes what it is.

In addition, FIG. 8 shows the temperature hysteresis of the above-mentioned thermally responsive device. That is, by regulating the operating stop length L by the first and second stoppers 5.6 as described above, the solid line in the figure shows the temperature hysteresis. As shown in , the operation start temperature T when the temperature is increased,
' is around 35℃, operation end temperature T when temperature rises, / is 37℃
The operating start temperature 11Z/ when the temperature drops is around 26℃.

The operation end temperature T4' when the temperature is set and lowered is around 23°C, and the temperature hysteresis ΔT is 37°C - 23"C = 14°C, which is much smaller than the conventional product. In other words, ΔT = 14 The value of °C is close to the temperature hysteresis of the alloy itself (A I-M f = 10 °C), which means that it can be used sufficiently for applications in a narrow temperature range. In the case of a product, the operating temperature TI, T, , T3 as shown by the broken line in FIG.
, T4, and the hot ejection hysteresis T, -T4 is more than twice that of the present example. In addition, the adhesion height Hs in Figure '$8 is 7. B Jl, operating stroke L
is 9U.

Also, ΔLt (see Figure 7) at this time is 3a and Δ
P, is 14gf=Also, ΔL, is 3tl, ΔP.

was 32 gf.

As is clear from the above description, this embodiment can reduce the temperature hysteresis to less than half that of the conventional device by cutting out the region where the spring height hardly changes even if the temperature changes in a conventional heat-responsive device. , it is possible to obtain a thermally responsive device that is stable against external force fluctuations. Therefore, use outdoors, equipment systems with a lot of mechanical vibration, gas fields, water! E
The 6-tooth function can also be applied to valves that fluctuate frequently.

Applications will expand significantly.

In addition, FIG. 9 shows a case where a bias band f') 10 is used instead of a weight as an example of the load applying body.

The load-deflection diagram is as shown in FIG. In other words, in the case of a bias spring, there is a weight and a dormer, and the load changes according to the change in deflection, but the operation t1'
+ The principle is the same as in the case of weights. In other words, the first
As shown in Figure 0, when the temperature is low, the pressing of ΔP1 generates a force when it hits the first stopper, while when the temperature is high, the pressing of ΔP1 generates a force.
L + ΔL for the required stroke L so that the pressing force of ΔP is exerted when it hits the stopper of .

Deflection of +452 or more? It may be a spring shape that can be bent.

Further, according to the present invention, the purpose of the south gate can be achieved if at least one of the l-th stopper and the $2 stopper is provided. Further, the specific shape of the shape memory spring can be modified in various ways, such as a shape memory spring in the shape of a plate spring or a torsion spring.

As explained above, according to the present invention, it is possible to significantly narrow the temperature hysteresis compared to conventional products,
It can also be used in applications with a narrow temperature range. In addition, it is very stable against fluctuations in fi 7 even under low congestion conditions and high temperatures.

It has a great effect on obtaining a versatile and high-performance heat c;, *Nh device that can be used even in environments with many external force fluctuations.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a conventional thermal cutoff device, Figure 2 (5),'
@Figure 2 (B), Figure 2 (Q is a diagram showing temperature hysteresis when external force is changed, Figure 3 is a schematic diagram showing the operating state at low temperature and high temperature in a conventional thermal response device, Figure 4 shows the load on a shape memory spring in a conventional thermal response device.
The deflection diagrams and FIG. 5 are the same. FIG. Figure 7 is a load-deflection diagram of the shape memory spring in the same example, Figure 8 is a diagram showing temperature hysteresis in one example, and Figure 9 is a schematic diagram when a bias spring is used as a load applying body. Figure 10 is a load-deflection diagram for the device in Figure 9. 1... Shape memory spring, 3... Weight (load applying body), 5... First stopper, 6... ...Second stopper, 10...Bias spring (loading body) 6) Chief agent Patent attorney Suzue Takehiko Patent Office Director General
Kazuo Wakasugi Tono 1゜ Indication Patent Application No. 1987-40495 2 Name of the invention Thermal response device using shape memory spring 3, relationship to the amended person case Patent applicant (464) Nichihatsujo Co., Ltd. Mainland 4. Agent Address: 17th Mori Building, 1-26-5 Toranomon, Minato-ku, Tokyo 6. Full text of the subject specification of supplementary IF 7. Engraving of the amended specification (no changes to the content)

Claims (1)

[Claims] A shape memory spring made of a shape memory alloy, a load applying body that applies a load in a direction to cause the shape memory spring to deflect, and a first stopper that prevents the shape memory spring from deflecting beyond a predetermined operating stroke at low temperatures or at high temperatures. A thermal response device using a shape memory spring, characterized in that the device further comprises at least one of a second stopper that prevents the shape memory spring from restoring beyond a predetermined operating stroke.